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Surgical management of complex spinal cord lipomas: how, why, and when to operate. A review
Abstract
This review summarizes the classification, anatomy, and embryogenesis of complex spinal cord lipomas, and it describes in some detail the new technique of total lipoma resection and radical reconstruction of the affected neural placode. Its specific mission is to tackle two main issues surrounding the management of complex dysraphic lipomas: whether total resection confers better long-term benefits than partial resection and whether total resection fares better than conservative treatment—i.e., no surgery—for asymptomatic lipomas. Accordingly, the 24-year progression-free survival data of the author and colleagues’ series of over 300 cases of total resection are compared with historical data from multiple series (including the author and colleagues’ own) of partial resection, and total resection data specifically for asymptomatic lesions are compared with the two known series of nonsurgical treatment of equivalent numbers of patients. These comparisons amply support the author’s recommendation of total resection for most complex lipomas, with or without symptoms. The notable exception is the asymptomatic chaotic lipoma, whose peculiar anatomical relationship with the neural tissue defies even this aggressive surgical approach and consequently projects worse results (admittedly of a small number of cases) than for the other two lipoma subtypes of dorsal and transitional lesions. Prophylactic resection of asymptomatic chaotic lipomas is therefore not currently endorsed.
... Traction on the conus determines the age of onset of symptoms in patients with SCM as a consequence of repetitive movements due to acute trauma or the aging process [29,30]. Spinal cord lipomas are progressive congenital disorders of the spinal cord [31]. Asymptomatic lipomas have a likelihood of 33-40% to deteriorate over 9-10 years [32,33]. ...
... Asymptomatic lipomas have a likelihood of 33-40% to deteriorate over 9-10 years [32,33]. Surgery, even in asymptomatic subjects, should be aimed to resect spinal cord lipomas as much as possible [31]. There are subtypes of spinal cord lipomas depending on how they develop during embryogenesis: dorsal lipoma, transitional lipoma, terminal lipoma, and chaotic lipoma [31]. ...
... Surgery, even in asymptomatic subjects, should be aimed to resect spinal cord lipomas as much as possible [31]. There are subtypes of spinal cord lipomas depending on how they develop during embryogenesis: dorsal lipoma, transitional lipoma, terminal lipoma, and chaotic lipoma [31]. Details of each lipoma type are beyond the scope of the present study. ...
Purpose: Split cord malformation (SCM) presenting concomitant with spinal teratoma without any open spinal dysraphism has rarely been reported in the literature. We aimed to make a systematic review and qualitative analysis of the literature about the topic and present the first case of SCM concomitant with spinal teratoma harboring papillary thyroid carcinoma (PTC) component.
Methods: Two big search tools (Pubmed/MEDLINE) and Scopus were used. The search strategy was compatible to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). An exemplary case of ours was also presented.
Results: There were 30 patients (15 pediatric and 15 adult). Female and male distribution was even. Median age of the patients was 18 years (range= 0-66 years). The most common presenting symptoms were back pain and lower limb weakness. Spinal teratoma and SCM mostly presented at thoracic/thoracolumbar region in children and lumbar region in adults. Surgical outcome was better in the children compared to the adults.
Conclusion: Thoracolumbar region is the most common location for such entity in children,
whereas lumbar region for the adults. Surgical resection should be done as much as possible under neuromonitorization. The resected material should be evaluated thoroughly not to miss any malign pathology. Surgical outcome is better when it is done at an early age.
... The role of lumbosacral lipoma surgery is to address these mechanical changes and mitigate the progressive neuro-uroorthopaedic symptoms. Following the publications of Pang et al. demonstrating excellent short-and long-term outcome with a radical lipoma resection approach [7][8][9], we adopted this technique in 2011. The goal of this technique is maximal lipoma resection guided by electrophysiology combined with expansion duraplasty in order to obtain optimal cord/ sac ratio. ...
... The last pre-operative MRI was reviewed independently by two assessors (PDV and DT) and the lipoma type was classified as dorsal, transitional, caudal, or chaotic [8,14] When there was disagreement, the scans were re-reviewed until a consensus was reached. Although we acknowledge that there can sometimes be a discrepancy between imaging and the actual peroperative findings, in this cohort we did not find any discrepancies between the imaging-based classification and the operative notes on, e.g. the presence of lipoma ventral to the dorsal root entry zone. ...
... Furthermore, a number of studies have indicated that this risk is similar between patients managed conservatively (typically with PFSs of 70-80% at 5 years and 60% at 10 years follow-up) [6,26] and for those undergoing conventional untethering surgery with partial lipoma resection (resection (typically ≤ 70-80% at 5 years and < 50% at 10 years [2,26,29,30]; Fig. 2) With only 2/81 patients (2%) with > 1 year follow-up and 2/34 patients (6%) with > 5 years follow-up requiring re-intervention for symptomatic retethering, our recurrence rate using total/near total resection is in line with that of other groups performing radical resections [16,17]. Pang et al. reported a 1% recurrence rate at 5 years postoperatively in virgin lipomas [8,16]. ...
Purpose
In 2009, Pang described a radical resection technique for congenital lumbosacral lipomas, with lower long-term symptomatic re-tethering rates compared with partial resections and conservative management, and low surgical morbidity. We adopted this technique in 2011, and aim to describe our first results.
Methods
In this monocentric retrospective audit, we included dorsal, transitional, chaotic, and caudal-type lumbosacral lipomas. Exclusion criteria were previously operated lipomas, pure filar lipomas, and concomitant major congenital anatomical urogenital/gastrointestinal abnormalities. Neuro-uro-orthopaedic status at presentation and at three months, one year and last postoperative follow-up, intraoperative electrophysiology, and extent of resection were collected.
Results
From January 2011 to September 2019, 91 patients were operated (median age 2y2m; 63 transitional; 14 caudal; 8 dorsal; 6 chaotic). Preoperatively, 67% were symptomatic. Preoperative and one-year postoperative rates of impaired ambulation (44% to 43%), hypoesthesia (8% to 5%), urodynamic/uroradiological abnormalities (49% to 37%), and foot/ankle deformities (8% to 5%) were comparable, whilst pain improved (25% to 5%) but catheterisation rates increased (21% to 36%). 23/92 (25%) suffered wound-related complications. 2/91 (2%) developed symptomatic re-tethering requiring second surgery. Mean cord/sac ratio was 0.47. 43% had > 20 mm³ residual fat, which improved with increasing surgical experience.
Conclusion
Radical lipoma resection, guided by intraoperative neuromonitoring, with reconstruction of the neural placode and expansion duraplasty is technically feasible and results in low rates of late deterioration and re-tethering. Lipoma-type and pre-operative status are important outcome predictors. Operative risks are not insignificant. Future studies need to determine appropriate selection criteria for surgery.
... CSF leaks are devastating complications that can lead to infection, inflammation and arachnoiditis, resulting in cord retethering [4], and subsequent neurosurgical sequelae. Previously, Pang described the surgical technique of performing a safe resection of complex spinal cord lipomas in detail, along with the nuances of reducing the risk of retethering [2]. However, the authors note that there is a paucity of literature given to the prevention and treatment of CSF leaks, particularly for this condition. ...
... Spinal lipomas are classified by Pang into dorsal, transitional, chaotic, and terminal types depending on the attachment of lipoma and involvement of conus, dorsal root entry zone (DREZ) and the nerve roots [2] (Fig. 1). A thorough understanding of the preoperative magnetic resonance imaging (MRI) to identify the subtype (and hence its resectability) and the ease of reconstruction of the neural placode is mandatory. ...
... A thorough understanding of the preoperative magnetic resonance imaging (MRI) to identify the subtype (and hence its resectability) and the ease of reconstruction of the neural placode is mandatory. Intraoperatively, deliberate exposure and identification of the cord, conus, DREZ, nerve roots, fusion line and the so-called 'white plane' as described by Pang [2], via meticulous circumferential dissection of the lipoma from the spinal cord is the key in performing a safe and radical dissection. These anatomical landmarks are summarized in Fig. 2. ...
Background
Congenital complex spinal lipomas (CSL) are challenging lesions to treat. Cerebrospinal fluid (CSF) leaks are feared complications due to the risk of infection, and subsequent scarring that may promote retethering. Much has been written in the literature on the surgical technique of CSL resection with less emphasis placed on the prevention and management of CSF leak.Method
The authors describe the nuances in the prevention and management of CSF leaks in the context of CSL, including the operative approach, resection, closure and recommended postoperative care.Conclusion
CSF leaks are complications that can be minimized with deliberate steps and meticulous surgical technique.
... Frequently, LMMC needs to be surgically resolved by way of untethering from the spinal cord and meninges in order to prevent or minimize neurological symptoms and allow normal development and growth of the CE. The role of prophylactic untethering in asymptomatic LMMC is a matter of debate [3]; however, most surgeons advocate it [4]. ...
... The implication of eCUSA in spinal LMMC as described in this study is relevant for chaotic and transitional lipomas (according to the classification of Pang, [4]). Dorsal lipomas, on the other hand, have a fusion line with the spinal cord or conus medularis, while the DREZ and nerve roots are located ventral to this fusion line. ...
... However, chaotic lipomas, and some of the transitional ones too, may include functional nerve roots which transvers the fatty tissue and should be identified and spared. Pang has also shown the importance of aggressive lipoma resection on reducing the rates of retethering [4]. Using the eCUSA, which elicits continuous EMG response during CUSA resection of the tissue could potentially enable a safer and more radical lipoma resection, improving untethering ability, and reducing the rates of retethering. ...
Background
Intraoperative neurophysiologic monitoring (IONM) is an established technique and adjunct of brain and spinal lesion resection surgery. In spina bifida syndrome surgery, mapping of the surgical wound is a common and accepted method in determining the position and functionality of nerve roots of the cauda equina (CE), especially when the anatomy is not straightforward and roots are splayed across or entangled within the lesion. Here, we describe a novel technique of continuous CE mapping using an electrified cavitron ultrasonic aspirator (eCUSA) in children with lipomyelomeningocele (LMMC) lesions.Methods
We assessed a method of dynamic CE mapping using an eCUSA as a stimulation probe. Twenty children (0.5–18 years) were included in this study, diagnosed with occult spina bifida LMMC in which the eCUSA stimulator was applied. IONM data and 2-weeks post-operative data were collected.ResultsLMMC lesions were located in the lumbar, sacral, and lumbosacral spine. eCUSA stimulation at 0.3–3.0 mA intensities elicited positive lower extremity muscle responses in 12 of the 20 patients included in the study. These responses allowed the surgeon real-time identification of the nerve roots tangent at the LMMC-cauda equina structure and intensive removal of the fat tissue in the area non-responding to the eCUSA stimulation.Conclusion
Continuous eCUSA-based stimulation of the cauda equina during LMMC resection is a feasible mapping technique with potential added value improving safety of untethering. Future studies evaluating extension of untethering, as well as the rates of retethering and long-term neurological and urological outcomes, are warranted.
... Lumbosacral lipoma (LSL) is one of the more severe forms of occult spinal dysraphism and may be associated with neurological, urological and orthopaedic complications [1][2][3][4]. In contrast to the spectrum of open neural tube defects (including myelomeningocoele), the abnormality is typically locoregional rather than pan central nervous system (CNS) [5]. ...
... In contrast to the spectrum of open neural tube defects (including myelomeningocoele), the abnormality is typically locoregional rather than pan central nervous system (CNS) [5]. Hydrocephalus and the Chiari II malformation are rarely seen in association with LSL or other occult dysraphic states [6,7], which is explained by the differing embryological origins of these dysraphic abnormalities [1,4]. ...
... Morphological type of LSL was classified according to the Pang classification [4], which is a modification of the Chapman classification based on x-ray myelography before advent of MRI [12]. Lipomas are classified based on their location and anatomy, distal conus and/or nerve root involvement. ...
Purpose
Lumbosacral lipoma (LSL) is a severe occult spinal dysraphism, frequently associated with neurological, urological and orthopaedic complications. Whole spine imaging is typically performed to identify concomitant, but spatially separate, congenital anomalies. Our hypothesis: the incidence of additional, clinically significant abnormalities of the neuraxis is low; thus, imaging should be optimised at the lumbosacral region. We aim to assess the prevalence and relevance of LSL-associated lesions.
Method
A single-centre, retrospective, radiological review using a prospectively maintained operative database. Inclusion criteria: children (< 16 years) with confirmed diagnosis of LSL and received whole spine MRI. Fatty filum, syndromic cases and cutaneous stigmata above lesion level were excluded. Data was extracted from radiological imaging, reports and clinical correspondence.
Results
One hundred twelve patients (40:72, M:F) aged 0.5 years (0.2–2.7) (median ± IQR) with LSL had whole spine MRI between 2001 and 2017. Classification of LSL: transitional 48 (43%); dorsal 30 (27%); caudal 28 (25%) and chaotic 6 (5%). Additional anomalies included syringohydromyelia 44 (39%), subcutaneous tract 19 (17%), abnormal vertebral segmentation 18 (16%), dermoid cyst 1 and 1 Chiari I deformity. There were no Chiari II malformations. No child required surgery for an associated lesion. Binary logistic regression revealed no factors associated with predicting secondary lesions.
Conclusions
In congenital LSL, additional anomalies of the neuraxis are typically loco-regional rather than pan-CNS and additional lesions are rarely clinically significant. The loco-regional distribution of anomalies suggests that only lumbosacral spinal imaging is required in the initial evaluation of LSL. Such a policy would lessen the anaesthetic/sedation time for children and reduce imaging cost per patient. MRI protocols could be refined to optimise imaging quality at the region of interest.
... Therefore, it is necessary to remove lesions that compress or pull the neural tissue [8]. Thorough evaluation and early neurosurgery are recommended to prevent the worsening of neural damage and to alleviate symptoms [9,10]. ...
... Although the presence and progression of symptoms is the basis for deciding to perform surgery [6,9], identifying symptoms in infants may be limited. For example, neurological deterioration, such as lower limb weakness and hypoesthesia, is difficult to detect [6]. ...
Purpose
The presence and progression of symptoms is the basis for deciding to perform surgery in infants with closed spinal dysraphism (CSD); however, identifying symptoms could be limited, making it difficult to decide. This study investigated whether an electrodiagnostic study (EDS) can provide evidence of neural damage in asymptomatic infants with CSD.
Methods
The study group comprised infants with CSD suspected of having neural damage based on structural abnormalities in spinal ultrasound findings. The patients’ medical records were reviewed retrospectively for their clinical presentation, neuroimaging findings, urodynamic study (UDS) results, EDS findings, and surgical status.
Results
Among 125 infants who underwent EDS and UDS, 117 (94%) had no clinical symptoms, except for cutaneous manifestations. Among these asymptomatic patients, 51 individuals (43.6%) had abnormal EDS findings; 33 subjects (28.2%) showed abnormal findings on EDS alone, while 37 (31.6%) on UDS alone, and 18 (15.4%) on both EDS and UDS. Chi-square test showed an opposite relationship between the two test results; when EDS was abnormal, UDS was often normal and vice versa (χ² = 5.328, p = 0.021). In all cases with abnormal EDS, denervation potentials, such as fibrillation and positive sharp waves, were observed on needle electromyography. However, abnormal findings in the nerve conduction study were observed only in six cases.
Conclusion
Subclinical neural damage was identified through EDS in asymptomatic infants with CSD. EDS could be necessary to determine whether follow-up monitoring only or surgical intervention is required for this patient group complementing UDS findings.
... To add interest to this "mixed" LDM-SCM situation, the current patient also harboured a classic terminal lipoma, a well-known defect of secondary neurulation [8][9][10], attached to an otherwise normal-looking conus, exemplifying a spinal cord with developmental defects in all three different stages of neural tube formation. ...
... The less spectacular of the two is the incorporation of malformations of all three main stages of neural tube embryogenesis in the same spinal cord: that of gastrulation (the SCM), primary neurulation (the LDM), and secondary neurulation (the terminal lipoma). Although such crisp display of this "triple entente" of spinal cord dysgenesis is distinctly uncommon, it has been seen and reported before [1][2][3][4][5][8][9][10][11]. ...
This is a case report of an exceedingly rare case of a limited dorsal myeloschisis (LDM) with its stalk inserted on the midline dorsal surface of one of a pair of hemicords in a type II split cord malformation. This entity, literally a “hemi-LDM,” has been seen only once by the senior author in his catalogue of over 200 cases of LDM (Pang et al., 2020), nor has it been reported elsewhere before. We postulate that here the mechanism of focal nondisjunction of the hemi-neural plate during primary neurulation, which produces LDMs, occurs at the cusp of the consecutive developmental stages of gastrulation and primary neurulation, right after the appearance of the hemi-neural plates and hemi-notochords caused by the endomesenchymal tract. This child also had a terminal lipoma attached to the end of the conus, indicating that disruption of all three tandem stages of neural tube formation, namely, gastrulation, primary neurulation, and secondary neurulation, can occur in the same individual.
... All children underwent magnetic resonance imaging (MRI) of the lumbosacral spine with additional T1-weighted axial cuts till the coccyx to look for the presence of a fatty filum terminale. Lipoma morphology was described as dorsal, transitional, chaotic, and terminal [17,18]. Transitional and chaotic lipomas were grouped together as "complex" lipomas for analysis. ...
... Valentini et al. [30] therefore recommend 6-monthly urodynamic assessments in children < 3 years of age undergoing conservative management of complex spinal dysraphisms. However, it must be also be remembered that symptom improvement in several domains is indeed possible after successful de-tethering, particularly when surgery is performed early [16,18,31]. In a prior publication from our institution, postnatally acquired deficits were reversible in 67.7% of children, and postoperative improvement was associated with a shorter latency between symptom onset and surgery [4]. ...
PurposeTo characterize the temporal profile of pre-operative deterioration in children with lipomyelomeningocele (LMMC) including those with congenital deficits and identify risk factors for clinical worsening.Methods
Records of 87 children who underwent surgery for LMMC were retrospectively reviewed to study the temporal profile of pre-operative deterioration, defined by the onset of new neurological dysfunction or progression of a pre-existing deficit. Preoperative magnetic resonance imaging (MRI) studies were examined to identify radiological features associated with deterioration. In children with extra-spinal placodes, the angle subtended by the terminal placode with the cord at the level of the laminar-fascial defect (“J sign”) was assessed.ResultsPre-operative deterioration in function was seen in 37 children (43%), occurring at a median age of 36 months and was more frequent in children without congenital deficits (54% versus 27%; p = 0.016). On Cox regression analysis, extra-spinal location of the placode (p = 0.003) and presence of a congenital deficit (p = 0.009) were positively and negatively associated with deterioration respectively. On Kaplan–Meier analysis, the median deterioration-free survival time was 72 months and was positively associated with presence of congenital deficit (p = 0.026) and negatively associated with presence of an extra-spinal placode (p < 0.001) or a meningocele sac (p = 0.001).Conclusion
Extra-spinal location of the neural placode was associated with higher risk of clinical deterioration in children with LMMC, whereas the presence of a congenital deficit conferred a decreased risk. Risk stratification based on clinical and radiological features can be used to guide decisions regarding early prophylactic surgery in children with LMMC.
... Based on these surgical results, the Paris and London groups concluded that watchful observation was superior to surgery in asymptomatic children with LMMC [20,37]. The better long-term outcomes reported in the more recent series wherein the rates of radical excision of lipomas was higher indicate that radical excision of lipomas should be the aim of surgery [24,33]. Italic font was used to indicate statistically significant p values (< 0.05) Fig. 2 Kaplan-Meier analysis of long-term surgical outcomes based on extent of surgical excision. ...
... Worsening of bladder function is the most common symptom at presentation after re-tethering [15,24]. It was present in all 6 children in our series, who presented with re-tethering. ...
AimTo determine the functional outcomes and risk factors for outcomes following surgery for lipomyelomeningocele (LMMC).Methods
Data from 109 children with LMMC who underwent surgery from January 2008 to December 2017 were retrospectively studied to evaluate functional outcomes and possible risk factors for early- (at discharge from hospital or within 1 month of surgery) and long-term outcomes after surgery.ResultsThere were 53 boys and 56 girls with median age of 36 months (IQR 12-90 months; range, 4 months to 18 years) at surgery. At presentation, neurological function was normal (asymptomatic group) in 28 (25.7%) children while there was neurological dysfunction (symptomatic group) in 81 (74.3%). Near total or radical excision of lipoma was done in 71 (65.1%) children. Six (5.8%) children had deterioration of neurological function in the post-operative period with recovery of function in three of them. There were no statistically significant risk factors for early outcomes. At a mean follow-up of 62.5 months (IQR 35–82 months; range, 12–146 months), 21 (27.6%) of the 76 symptomatic group children (including 59.3% with incomplete bladder dysfunction) showed improvement, 52 (68.4%) remained the same, while 3 (4%) deteriorated. In 31 children (symptomatic group) who developed symptoms after 1 year of age, early surgery after development of symptoms was associated with better chances of recovery (p = 0.0008). In the asymptomatic group, 23 (88.5%) had normal neurological function at mean follow-up of 57.5 months (IQR 30–77 months; range, 12–141 months) and 3 (11.5%) had neurological deterioration. The mean time to late deterioration (re-tethering) from surgery was 51.3 months (IQR 24–75 months; range, 24–84 months). Presence of syrinx on initial MRI (p = 0.008) and partial resection of the lipoma (p = 0.02) were independent risk factors for delayed deterioration.Conclusion
Radical resection of LMMC probably helps in preserving neurological function in > 90% of children at long-term follow-up. Fifty-five percent of children > 2 years of age with incomplete bladder dysfunction regained normal function following surgery. In children who develop symptoms after birth, early surgical intervention can reverse the neurological deficits.
... All patients younger than 19 years of age diagnosed with FFT who underwent intervention by the Neurosurgical Service, KK Women's and Children's Hospital, were included. Exclusion criteria were as follows: patients aged 19 years or older, patients who had other forms of occult spinal dysraphism such as complex spinal lipomas (as previously described 23,24 ), patients with a tethered cord secondary to focal nondisjunction of the primary neural tube (such as congenital dermal sinus tract and limited dorsal myeloschisis), patients with occult TCS, and patients with incomplete clinical information. ...
OBJECTIVE The role of prophylactic detethering a fibrofatty filum terminale (FFT) remains equivocal. Furthermore, long-term studies focusing on urological outcomes are sparse. The aims of this study were to present an institutional experience on the perioperative and long-term outcomes of FFT surgery and to assess for factors that contribute to post-operative clean intermittent catheterization (CIC). METHODS This was a single-institution, retrospective study conducted over a 20-year period. Patients younger than 19 years of age who underwent surgery for FFT were included. Variables of interest included patient demographics, clinical presentation, radiological findings, postoperative complications, and long-term need for CIC. Outcomes were measured using the Necker functional score and modified Hoffer Functional Ambulation scale score at 3, 6, and 12 months postdis-charge. RESULTS A total of 164 surgeries were performed for FFT from 2000 to 2020. The median age at surgery was 1.1 years, and the mean follow-up duration was 8.3 years. There were 115 patients (70.1%) who underwent prophylactic-intent surgery and 49 patients (29.9%) who underwent therapeutic-intent surgery. The proportion of therapeutic-intent surgeries increased significantly with age percentiles (0-20th, 21.9%; 20th-40th, 9.1%; 40th-60th, 18.2%; 60th-80th, 36.4%; and 80th-100th, 63.6% [p < 0.001]). Thirty patients (18.3%) had an associated syndrome, the most common (n = 19, 11.6%) being VACTERL (vertebral defects, anal atresia, cardiac defects, tracheo-esophageal fistula, renal anomalies , and limb abnormalities). Forty-eight patients (29.3%) had an associated malformation (anorectal anomaly = 37, urogenital anomaly = 16, and sacral anomaly = 3). Cutaneous manifestation was the most common presentation (n = 96, 58.5%), followed by lower-limb neurological deficits (n = 21, 12.8%). A low-lying conus was present in 36.0% of patients (n = 59), and 16.5% had an associated syrinx (n = 27). There were 26 patients (18.8%) with an abnormal preoperative urodynamic study. Three patients (1.8%) had postoperative complications that required repeat surgery. There were no cases of CSF leakage. One patient (0.6%) developed retethering requiring another surgery. Postoperative CIC was required in 11 patients (6.7%). Multivariable analyses showed that an abnormal preoperative urodynamic study (adjusted OR 5.5 [95% CI 1.27-23.9], p = 0.023) and having an intraspinal syrinx (adjusted OR 5.29 [95% CI 1.06-26.4], p = 0.042) were associated with the need for CIC. CONCLUSIONS The authors' results demonstrate that detethering surgery for FFT is a relatively safe procedure and can be performed prophylactically. Nonetheless, the risks of postoperative CIC should be emphasized during the preop-erative counseling process. https://thejns.org/doi/abs/
... All patients younger than 19 years of age diagnosed with FFT who underwent intervention by the Neurosurgical Service, KK Women's and Children's Hospital, were included. Exclusion criteria were as follows: patients aged 19 years or older, patients who had other forms of occult spinal dysraphism such as complex spinal lipomas (as previously described 23,24 ), patients with a tethered cord secondary to focal nondisjunction of the primary neural tube (such as congenital dermal sinus tract and limited dorsal myeloschisis), patients with occult TCS, and patients with incomplete clinical information. ...
OBJECTIVE
The role of prophylactic detethering a fibrofatty filum terminale (FFT) remains equivocal. Furthermore, long-term studies focusing on urological outcomes are sparse. The aims of this study were to present an institutional experience on the perioperative and long-term outcomes of FFT surgery and to assess for factors that contribute to postoperative clean intermittent catheterization (CIC).
METHODS
This was a single-institution, retrospective study conducted over a 20-year period. Patients younger than 19 years of age who underwent surgery for FFT were included. Variables of interest included patient demographics, clinical presentation, radiological findings, postoperative complications, and long-term need for CIC. Outcomes were measured using the Necker functional score and modified Hoffer Functional Ambulation scale score at 3, 6, and 12 months postdischarge.
RESULTS
A total of 164 surgeries were performed for FFT from 2000 to 2020. The median age at surgery was 1.1 years, and the mean follow-up duration was 8.3 years. There were 115 patients (70.1%) who underwent prophylactic-intent surgery and 49 patients (29.9%) who underwent therapeutic-intent surgery. The proportion of therapeutic-intent surgeries increased significantly with age percentiles (0–20th, 21.9%; 20th–40th, 9.1%; 40th–60th, 18.2%; 60th–80th, 36.4%; and 80th–100th, 63.6% [p < 0.001]). Thirty patients (18.3%) had an associated syndrome, the most common (n = 19, 11.6%) being VACTERL (vertebral defects, anal atresia, cardiac defects, tracheo-esophageal fistula, renal anomalies, and limb abnormalities). Forty-eight patients (29.3%) had an associated malformation (anorectal anomaly = 37, urogenital anomaly = 16, and sacral anomaly = 3). Cutaneous manifestation was the most common presentation (n = 96, 58.5%), followed by lower-limb neurological deficits (n = 21, 12.8%). A low-lying conus was present in 36.0% of patients (n = 59), and 16.5% had an associated syrinx (n = 27). There were 26 patients (18.8%) with an abnormal preoperative urodynamic study. Three patients (1.8%) had postoperative complications that required repeat surgery. There were no cases of CSF leakage. One patient (0.6%) developed retethering requiring another surgery. Postoperative CIC was required in 11 patients (6.7%). Multivariable analyses showed that an abnormal preoperative urodynamic study (adjusted OR 5.5 [95% CI 1.27–23.9], p = 0.023) and having an intraspinal syrinx (adjusted OR 5.29 [95% CI 1.06–26.4], p = 0.042) were associated with the need for CIC.
CONCLUSIONS
The authors’ results demonstrate that detethering surgery for FFT is a relatively safe procedure and can be performed prophylactically. Nonetheless, the risks of postoperative CIC should be emphasized during the preoperative counseling process.
... All patients younger than 19 years of age diagnosed with FFT who underwent intervention by the Neurosurgical Service, KK Women's and Children's Hospital, were included. Exclusion criteria were as follows: patients aged 19 years or older, patients who had other forms of occult spinal dysraphism such as complex spinal lipomas (as previously described 23,24 ), patients with a tethered cord secondary to focal nondisjunction of the primary neural tube (such as congenital dermal sinus tract and limited dorsal myeloschisis), patients with occult TCS, and patients with incomplete clinical information. ...
... The treatment of spinal lipomas depends on the severity and location of the tumor. In 2019, Pang et al. demonstrated that PFS was higher with total resection of complex dysraphic lipomas than partial resection [38]. In addition, the investigators show that PFS is higher with prophylactic total resection of asymptomatic dorsal and transitional lipomas than conservative treatment (no surgery). ...
The prevalence of spinal tumors is rare in comparison to brain tumors which encompass most central nervous system tumors. Tumors of the spine can be divided into primary and metastatic tumors with the latter being the most common presentation. Primary tumors are subdivided based on their location on the spinal column and in the spinal cord into intramedullary, intradural extramedullary, and primary bone tumors. Back pain is a common presentation in spine cancer patients; however, other radicular pain may be present. Magnetic resonance imaging (MRI) is the imaging modality of choice for intradural extramedullary and intramedullary tumors. Plain radiographs are used in the initial diagnosis of primary bone tumors while Computed tomography (CT) and MRI may often be necessary for further characterization. Complete surgical resection is the treatment of choice for spinal tumors and may be curative for well circumscribed lesions. However, intralesional resection along with adjuvant radiation and chemotherapy can be indicated for patients that would experience increased morbidity from damage to nearby neurological structures caused by resection with wide margins. Even with the current treatment options, the prognosis for aggressive spinal cancer remains poor. Advances in novel treatments including molecular targeting, immunotherapy and stem cell therapy provide the potential for greater control of malignant and metastatic tumors of the spine.
... BCR, according to these authors, could be used to assess the anatomical and functional integrity of the sensorimotor reflex arc, which includes both parasympathetic and pudendal innervation (33,34) and thus show how intraoperative BCR changes could be used to predict bladder function. The autonomic nervous system (pelvic parasympathetic) and the somatic nervous system (pudendal nerve) are both governed by very similar but distinct pathways (35). Interneuronal networks promote the integration of these systems. ...
Background
Tumors of the pre-sacral and sacral spaces are a rare occurrence in children. Total tumor excision is required due to the significant risk of relapse in the event of partial surgery, but the surgical procedure may lead to postoperative problems such as urinary, sexual, and anorectal dysfunctions. Intraoperative neuromonitoring (IONM) has gained popularity in recent years as a strategy for preventing the onset of neurologic impairments by combining several neurophysiological techniques. The aim of our study is to describe the experience of Bambino Gesù Children’s Hospital in the use of IONM in pediatric pelvic surgery.Materials and Methods
The data of patients treated for pelvic malignancies at Bambino Gesù Children’s Hospital from 2015 to 2019 were retrospectively collected. All patients were assessed from a neurologic and neuro-urologic point of view at different time-points (before and immediately after surgery, after 6 months, and 1-year follow-up). They were all monitored during a surgical procedure using multimodal IONM including transcranial motor evoked potentials (TcMEP), triggered-EMG (t-EMG), pudendal somatosensory evoked potentials (PSSEP), and bulbocavernosus reflex (BCR).ResultsDuring the study period, ten children underwent pelvic tumor removal at our Institution. In all cases, intraoperative neurophysiological recordings were stable and feasible. The preservation of neurophysiological response at the same intensity during surgical procedures correlated with no new deficits for all neurophysiological techniques.DiscussionAlthough the impact of the IONM on surgical strategies and clinical follow-up is unknown, this preliminary experience suggests that the appropriate use of several neurophysiological techniques can influence both the radicality of pelvic tumor removal and the neurological and urological outcome at clinical follow-up. Finally, because of the highly complex anatomy and inter-individual variances, this is especially useful in this type of surgery.
... In type 2 caudal regression, the sacral hypogenesis is usually less severe with a tethered and low-lying cord. These have been described with chaotic lipomas, in which the cord-lipoma interface is irregular and suggests disorganized secondary neurulation, a feature that helps to direct surgical planning but would be better assessed with MRI [52]. Caudal regression, given its basis in the abnormal development of the caudal cell mass, is associated with other hindgut and genitourinary malformations [4]. ...
Ultrasonography (US) is the first-line imaging modality for screening neonates and young infants with suspected spinal abnormalities. Whether performed for a suspicious congenital skin lesion, such as a lumbosacral tract or lipomatous mass, or abnormal neurological findings, US can help define spinal anatomy, characterize congenital spine malformations, and direct further work-up and management. The purpose of this article is to review the diagnostic imaging approach to infant spine US, including technique and indications, normal anatomy and variants with a focus on embryological origins, and classification and diagnosis of congenital spine malformations.
... There is a growing belief among surgeons that aggressive total resection of intradural lipomas is associated with poor out come and not required for neurologic improvements 5) . Though controversial, there is some evidence to suggest there is a high rate of recurrence, roughly 50% with partial resection at 2-10 years postoperativley, though many of these studies analyzed outcomes in patients with lumbosacral lipomyelomeningoceles, which may have a different natural history than presented in this rare case report 12,13) . ...
An unusual case of a thoracic spine lipoma presenting with profound progressive numbness along with difficult to interpret preoperative imaging is discussed. A uniquely minimally invasive surgical treatment approach with successful outcome and improved neurologic symptoms is presented. A literature review and discussion of the benefits and limitations of a minimally invasive surgical technique are provided. A male presented with several months of progressive bilateral lower extremity numbness that ascended to the mid-thoracic spine. Spine magnetic resonance imaging demonstrated a 9 mm intradural, thoracic spinal mass, which was thought preoperatively to represent an arachnoid cyst with an adhesion or a localized dural ectasia. Subsequent imaging demonstrated a band at the cranial margin of the mass appearing to tether the spinal cord to the dorsal-lateral spinal canal without an arachnoid cyst or osseous defect. Surgical exploration revealed an intradural exophytic, intramedullary fatty mass tethering the spinal cord to the dorsolateral dura. An abnormal patch of dura was observed overlying the fatty attachment but no dural defect was identified. Pathology demonstrated fragments of fibroconnective tissue, scattered mature adipocytes, and entrapped meningeal cells, yielding the diagnosis of a spinal cord lipoma. Follow up imaging demonstrated no residual tethering of the spinal cord.
... Although there exist controversy over the indication of surgery in the case of complex lipomas, Pang recommends total resection for most complex lipomas with or without symptoms. With respect to asymptomatic chaotic lipomas, prophylactic resection is not currently endorsed (85). ...
Introduction:
Defective closure of the neural tube affects different systems and generates sequelae, such as neurogenic bladder (NB). Myelomeningocele (MMC) represents the most frequent and most severe cause of NB in children. Damage of the renal parenchyma in children with NB acquired in postnatal stages is preventable given adequate evaluation, follow-up and proactive management. The aim of this document is to update issues on medical management of neurogenic bladder in children.
Materials and methods:
Five Pediatric Urologists joined a group of experts and reviewed all important issues on "Spina Bifida, Neurogenic Bladder in Children" and elaborated a draft of the document. All the members of the group focused on the same system of classification of the levels of evidence (GRADE system) in order to assess the literature and the recommendations. During the year 2020 the panel of experts has met virtually to review, discuss and write a consensus document.
Results and discussion:
The panel addressed recommendations on up to date choice of diagnosis evaluation and therapies. Clean intermittent catheterization (CIC) should be implemented during the first days of life, and antimuscarinic drugs should be indicated upon results of urodynamic studies. When the patient becomes refractory to first-line therapy, receptor-selective pharmacotherapy is available nowadays, which leads to a reduction in reconstructive procedures, such as augmentation cystoplasty.
... El empleo de estimulación directa de raíces nerviosas a nivel lumbosacro ha sido sobre todo descrito en casos de rizotomías dorsales selectivas para el tratamiento de la espasticidad en la parálisis cerebral infantil 11 , así como en los lipomas espinales complejos 12 y en la liberación de la médula anclada 13 . Las características radiológicas y las relaciones anatómicas del caso que nos ocupa hicieron que la cirugía fuera planificada como la de un lipoma del filum terminale 12 . Tal y como se desprende de la literatura 11-13 y de la descripción realizada en nuestro caso, resulta crucial el empleo de la estimulación directa para reconocer la funcionalidad de las raíces nerviosas relacionadas con la lesión y llevar a cabo la extirpación quirúrgica de una forma segura. ...
Resumen
Varón de 45 años, sin antecedentes de interés, que acudió a urgencias con cuadro progresivo de pérdida de fuerza en miembros inferiores a nivel distal con imposibilidad para la flexión dorsal del pie izquierdo, acompañado de disfunción neurógena de vejiga. En la RM se objetivó una lesión a nivel del filum terminale que interesaba completamente el diámetro transversal del saco dural, siendo la impresión diagnóstica radiológica de lipoma del filum terminale. Se llevó a cabo cirugía con monitorización neurofisiológica intraoperatoria empleando estimulación directa de raíces nerviosas, lo que permitió la extirpación de una tumoración compuesta por material sebáceo, grasa y pelo. El diagnóstico anatomopatológico fue de teratoma quístico maduro. El paciente presentó evolución postoperatoria favorable.
... In 2009 and 2010 59,60) , my colleagues and I published our early series of 238 patients who had total/near-total resection of complex lipomas and compared their short and long term outcomes with our prior series of 116 patients with partial resection. In 2013, we updated our series of total resection to 315 cases 60) , and recently, our number has risen to over 450 cases 53,55) . Our ever enlarging data pool unfailingly shows an overwhelming advantage of total over partial resection in almost all respects, but the subset of asymptomatic virgin lipomas continues to pique uncertainties and controversies among some paediatric neurosurgeons. ...
This review summarises the classification, anatomy and embryogenesis of complex spinal cord lipomas, and describes in some detail the new technique of total lipoma resection and radical reconstruction of the affected neural placode. Its specific mission is to tackle two main issues surrounding the management of complex dysraphic lipomas : whether total resection confers better long term benefits than partial resection, and whether total resection does better than conservative treatment, i.e., no surgery, for asymptomatic lipomas. Accordingly, the 24 years progression-free survival data of the author and colleagues' series of over 350 cases of total resection are compared with historical data from multiple series (including our own) of partial resection, and total resection data specifically for asymptomatic lesions are compared with the two known series of non-surgical treatment of equivalent patients. These comparisons amply support the author's recommendation of total resection for most complex lipomas, with or without symptoms. The notable exception is the asymptomatic chaotic lipoma, whose peculiar anatomical relationship with the neural tissue defies even our aggressive surgical approach, and consequently projects worse results (admittedly of small number of cases) than for the other two lipoma subtypes of dorsal and transitional lesions. Prophylactic resection of asymptomatic chaotic lipomas is therefore not currently endorsed.
Spinal cord injury (SCI) affects approximately 1.3 million people living in the United States. Most research efforts have been focused on reversing paralysis, as this is arguably the most defining feature of SCI. The damage due to SCI, however, extends past paralysis and includes other debilitating outcomes including immune dysfunction and gut dysbiosis. Recent efforts are now investigating the pathophysiology of and developing therapies for these more distal manifestations of SCI. One exciting avenue is the spinal cord-gut-immune axis, which proposes that gut dysbiosis amplifies lesion inflammation and impairs SCI recovery. This review will highlight the most recent findings regarding gut and immune dysfunction following SCI, and discuss how the CNS, gut, and immune system all coalesce to form a bidirectional axis that can impact SCI recovery. Finally, important considerations into how the spinal cord-gut-immune axis fits within the larger framework of therapeutic development (i.e., probiotics, fecal transplants, dietary modifications) will be discussed, emphasizing the lack of interdepartmental investigation and the missed opportunity to maximize therapeutic benefit in SCI.
OBJECTIVE
The aims of this study were to characterize syringomyelia in patients with lipomyelomeningocele (LMMC) and investigate the association between the presence of a syrinx and patient neurological deficits.
METHODS
Patients with LMMC who had been admitted between 2007 and 2020 were included in the study. Syringomyelia on magnetic resonance imaging (MRI) was classified into three groups: true syrinx, early syrinx, and presyrinx. The correlation of clinical deficits (at birth, new onset, and progressive) and type of lipoma with the presence and type of syrinx was studied.
RESULTS
Among a total of 140 patients, the median age was 2.5 (IQR 1.3–9) years. Neurological deficits were present at birth in 75 (53.6%) patients, but 67 (47.9%) had new-onset deficits or progression of their birth deficits. The most common type of spinal lipoma was the transitional type (75.7%). Thirty-nine (27.9%) patients had a syrinx (37 with a true syrinx, 2 with an early syrinx), and 25 (17.9%) patients had a presyrinx. There was no significant correlation between the presence of a syrinx and patient neurological deficits. However, patients with a syrinx that was not adjacent to the lipoma (≥ 1 vertebral level away) had a higher incidence of deficits at birth (p = 0.045), whereas those with a syrinx spanning ≥ 5 vertebral levels had a higher incidence of progressive neurological deficits (p = 0.04). Six (75%) of 8 patients in whom serial MRI had shown syrinx progression had clinical worsening.
CONCLUSIONS
Syrinx location with respect to the spinal lipoma, syrinx length, and progressive syringomyelia may have clinical significance in patients with LMMC.
OBJECTIVE
Spinal lipomas are congenital malformations. They do not express tumorous growth but are found to increase in volume like other normal subcutaneous fat tissue during the early postnatal period. To understand the natural course of volume changes in spinal lipomas, the authors measured the changes in size of spinal lipomas together with the normal subcutaneous fat in relation to BMI.
METHODS
A total of 27 patients with conus spinal lipoma excluding lipomyelomeningocele who underwent MRI twice before surgery (on initial diagnosis and immediately preoperatively) were included. Patients’ ages at the time of the first MRI ranged from 0 to 32 months (mean 2.9 months, median 1 month). Candidates were categorized by age into three groups: < 1 month, 1–2 months, and ≥ 3 months. The growth rate of the spinal lipomas (in three directions), change in thickness of the normal subcutaneous fat, growth rate of the normal spinal canal (dorsoventral direction), and change in BMI were retrospectively analyzed between the three groups.
RESULTS
The mean interval between MRI studies was 83.1 days. During this time, the mean lipoma growth rates were 199%, 149%, and 133% in the dorsoventral, lateral, and craniocaudal directions, respectively (with 100% representing the first measurement). The mean change in the thickness of the normal subcutaneous fat was 183%. The mean growth of the normal spinal canal was 111%. The mean increase in BMI was 124%. These rates were all significantly higher in the younger groups. There was no significant difference in the growth rates between the lipoma and the subcutaneous fat in every age group. In contrast, the growth rate of the lipoma significantly exceeded that of the spinal canal in patients younger than 3 months. The subarachnoid space around the lipoma became obstructed in 35.3%, and spinal cord distortion occurred in 48.1% of the patients younger than 3 months.
CONCLUSIONS
Spinal lipomas rapidly increase in volume before the age of 3 months and especially in infants younger than 1 month. Their features closely correlate with the physiological growth of the normal subcutaneous fat and the increase in BMI. The rapid growth of lipomas suggests the importance of close observation in this period, keeping in mind the typical anatomical changes of lipomas and their surrounding structures.
The non dysraphic lipomas are a rare form of congenital spinal anomaly. These are most commonly situated within the filum or attached to the conus and rarely can be subpial or intramedullary in the cervical or thoracic region. The subtype of dorsal lipomas occur due to premature dysjunction during primary neurulation while the conal and filar lipomas occur due to developmental aberration during phases of secondary neurulation. Magnetic Resonance Imaging (MRI) is the primary mode of investigation to see the level, morphology and extent of the lesion as well as to recognise associated anomalies.
Chaotic lipomas are an extremely rare variant of spinal lipomas. This entity was first defined in 2009 by Pang and colleagues. Not much has been written about this variant. Its characteristic is the haphazard distribution of DREZ (Dorsal root entry zone), nerve roots and placode-lipoma interface. Thus complete/near-total excision of this lesion is quite difficult. We describe a case of chaotic spinal lipoma and elucidate the challenges faced in the management of this entity and review the literature. We performed a thorough systematic review with the keyword ‘chaotic’, ‘Lipomyelomeningocele’, ‘Complex Lipomyelomeningocele’, ‘LMMC’, ‘Lumbar lipoma’, ‘spinal lipoma’ in the google scholar and PUBMED data system for indexed literature on the above topic with no particular time frame. The studies quoted range earliest from 1970 till currently. Additional potential relevant articles were further retrieved through a manual search of references from original reports. Out of 42 studies, a total of 21 publications were selected which could have encountered a chaotic variant, but due to the term introduced only recently in 2009, may have been described differently. Studies encompassing true lipomeningomyelocele were excluded from our review. What we found out? Chaotic lipoma may not be a new entity. The scarce description in literature may be in part due to non-introduction and unclear description of this term earlier. The management of this variant is particularly challenging with basic principles remaining the same. Meticulous near-total excision and placode-lipoma construct are the major obstacles.
OBJECTIVE
Lipoma of the conus medullaris (LCM) causes neurological symptoms known as tethered cord syndrome (TCS). The symptoms can be seen at diagnosis and during long-term follow-up. In this report, pediatric patients with LCMs who underwent untethering surgery, under the policy of performing surgery if diagnosed regardless of symptoms, were retrospectively reviewed to evaluate long-term surgical outcomes. Possible risk factors for retethered cord syndrome (ReTCS) were evaluated in the long-term follow-up period.
METHODS
A total of 51 consecutive pediatric patients with LCMs who underwent a first untethering surgery and were followed for > 100 months were retrospectively analyzed. The surgery was performed with the partial removal technique. Pre- and postoperative clinical and radiological data were reviewed to analyze the outcomes of surgery and identify potential risk factors for ReTCS.
RESULTS
During follow-up, 12 patients experienced neurological deterioration due to ReTCS. The overall 10-year and 15-year progression-free survival rates were 82.3% and 75.1%, respectively. On univariate analysis, a lipoma type of lipomyelomeningocele (OR 11, 95% CI 2.50–48.4; p = 0.0014), patient age at the time of surgery (OR 0.41, 95% CI 0.14–1.18; p = 0.0070), and the mean patient growth rate after surgery (OR 2.00, 95% CI 1.12–3.41; p = 0.0040) were significant factors associated with ReTCS. Cox proportional hazard models showed that a lipoma type of lipomyelomeningocele (HR 5.16, 95% CI 1.54–20.1; p = 0.010) and the mean growth rate after surgery (HR 1.88, 95% CI 1.00–3.50; p = 0.040) were significantly associated with the occurrence of ReTCS.
CONCLUSIONS
More complex lesions and a high patient growth rate after surgery seemed to indicate increased risk of ReTCS. Larger prospective studies and registries are needed to define the risks of ReTCS more adequately.
Spina bifida and tethered spinal cord are congenital diseases that can lead to severe disability. At present, most doctors in relevant specialties in China still have insufficient understanding of spina bifida, resulting in high incidence and aggravation of its complications. To provide guidance for the diagnosis and treatment of spina bifida and tethered spinal cord in China, experts from neurosurgery, urology, orthopedics, spine surgery, and rehabilitation departments who have experiences in the diagnosis and treatment of spina bifida discussed and summarized their experiences, and referred to the relevant literature on the diagnosis and treatment of spina bifida at home and abroad. Expert consensus was formed in the following aspects: concept, classification, and pathological changes of spina bifida; diagnosis; treatment process and operation timing; principles and methods of treatment; rehabilitation; and follow up. This expert consensus can provide reference for relevant care providers of spina bifida in China.
The most common surgical procedures for the spine by age group are as follows: myelomeningocele (MMC) repair in neonates, spinal lipoma resection in infants and toddlers, and correction of idiopathic spinal scoliosis in school-age children. Less frequent surgeries include the procedures for congenital spinal deformities, tumors, or vascular anomalies such as spinal arteriovenous malformation (AVM), cavernous malformation, dural arteriovenous fistula (AVF), and capillary telangiectasia. For safe and effective anesthetic management during spine surgery, the child should be placed in a comfortable prone position. An appropriate anesthetic protocol suitable for intraoperative neural monitoring should be chosen to minimize the risk of spinal nerve injury. It is not practical to make a “one size fits all” statement about anesthetic management for pediatric spine surgery since different types of such surgeries have different anesthetic considerations. For example, in patients undergoing MMC repair, attention should be paid to protecting the exposed neural tissue when introducing anesthesia. In patients undergoing spinal lipoma removal and tethered cord release, anesthetic management suitable for intraoperative neurophysiological monitoring (IONM) should be implemented to preserve function. For patients undergoing idiopathic scoliosis correction, the focus should be on appropriate anesthetic management for IONM, preparation for the possibility of bleeding, and postoperative pain management. The following sections will discuss the perioperative management for pediatric patients with common spine diseases like MMC, spinal lipoma, and idiopathic scoliosis and less common conditions like spinal tumors, vascular malformations, and neurofibromatosis.
BACKGROUND: Congenital malformations of the spine and spinal cord can be combined with various clinical manifestations of the spine, spinal cord, and lower extremities. Children with these neurological disorders often lack sensitivity and motor activity of their lower extremities and, in most cases, have bladder infections and incontinence (lack of bladder and bowel control). AIM: This study aims to analyze publications with the diagnostic and treatment results of patients with neurological, orthopedic, neurological, and ophthalmological problems with spina bifida. MATERIALS AND METHODS: We searched PubMed, Web of Science, Scopus, MEDLINE, eLibrary, and RSCI databases and found about 2000 references and 374 articles. We selected 60 articles for review in orthopedics, neurosurgery, urology, and ophthalmology. RESULTS: Neural tube defects are a wide range of congenital malformations, including skull defects and open or closed spinal dysraphism. The incidence of spine and spinal cord malformations in different countries is quite broad and amounts to 0.3199.4 cases per 10,000 births worldwide. Spinal cord malformations often occur in combination with bladder infections and incontinence, limb deformities, and other central nervous system developmental anomalies. Among the orthopedic problems leading to impaired support function, the most common are foot deformities and hip joint instability. Orthopedic monitoring of a patient with spina bifida consists of mainly preventing or correcting deformities according to the rehabilitation potential of the child. The timely completion of treatment allows the child to maintain mobility and independence of movement daily activities. At the same time, such treatment must pursue realistic goals according to the potential motor level of the child. In addition to neurosurgical and orthopedic problems, most children with spina bifida (88%94%) suffer from pelvic disorders. A urologist should observe a patient with spina bifida to perform ultrasound and laboratory monitoring of both the lower and upper urinary tract conditions from an early age. Timely procedures to eliminate urinary retention and sanitation can maintain normal kidney function and contribute to the adequate conduct of motor and neurological rehabilitation of the child. The most common complication of spina bifida is the Chiari II malformation, which is manifested by damage to brain stem structures and internal occlusal hydrocephalus with various symptoms, including neuroophthalmological signs. CONCLUSIONS: A multidisciplinary team of specialists comprising a neurologist, neurosurgeon, urologist, orthopedic surgeon, ophthalmologist, orthosis specialist, and psychologist should be involved in treating the children with the above presented problems. The use of an integrated approach to treat this group is absolutely justified and enabled the maximum rehabilitation potential of the child to be achieved.
Neurochirurgischer Interventionsbedarf bei neuromotorischen Erkrankungen entsteht durch den – drohenden – Funktionsverlust neuronaler Regelkreise. Auslöser sind die vaskulär kompromittierende Kompression, die direkte Zerstörung oder aber die funktionelle Dysbalance intakter Leitungsbahnen. Die strategischen Ziele neurochirurgischer Eingriffe beschränken sich deshalb auf Rekonstruktion, Dekompression oder selektive funktionelle Unterbrechung neuraler Leitungsbahnen. Während im Falle einer peripheren Nervenläsion eine direkte oder indirekte Rekonnektion angestrebt wird, stehen der spinalen oder der kraniellen Neurochirurgie nur die Optionen der Resektion funktionsbedrohender pathologischer Gewebe oder der selektiven Unterbrechung funktionell kontraproduktiver, physiologischer oder pathologischer Impulswege zur Verfügung. Überwiegend handelt es sich bei diesen Eingriffen um komplexe, mikrochirurgische Präparationen, die einer elektrophysiologischen Begleitung bedürfen.
Large dural graft of bovine pericardium is measured exactly to size and sutured to dural edges with a running 5-0 prolene suture. This is to create a large cord-sac ratio.
OBJECTIVE
The objective of this study was to assess the prevalence and spectrum of spinal dysraphism in a cohort of children with cloacal exstrophy (CEX) using MRI.
METHODS
Children with CEX presenting between 1999 and 2019 with baseline spinal MRI were included. The images were reviewed in consensus to assess the type of dysraphism. The dysraphisms were initially reviewed and described based on their descriptive anatomy, and then classified according to anomalies of gastrulation, primary neurulation, or secondary neurulation.
RESULTS
Thirty-four children were included. Thirty-three of these children had closed spinal dysraphism, and 1 had a normal spine. Of the 33 cases of closed spinal dysraphism, the conus and/or filum terminale were involved in all cases. The most common malformations were spinal lipoma (n = 20) and terminal myelocystocele (n = 11). The lipomas were heterogeneous: 4 dorsal, 9 transitional, 4 chaotic, and 3 terminal. A large subgroup (10/20, 50%) within the lipomas had an unusual morphology of noncontiguous double lipomas, the proximal fat related to the conus and the distal fat within the filum. These were difficult to characterize using existing classifications. In 2 cases, only a thickened filum was noted. The majority of these malformations were compatible with a disorder of secondary neurulation.
CONCLUSIONS
Complex spinal dysraphisms are consistently associated with CEX. The unusual dysraphism patterns found in this group of patients highlight the limitations of current embryological classifications. Given the propensity for neurological deterioration in this group of patients, spinal MRI should be routinely performed. The type and distribution of malformations seen have implications for the wider understanding of the pathogenesis and classification of lumbosacral lipomas.
Spinal meningiomas are classically intradural extramedullary tumors that arise from arachnoid cap cells in close proximity to the dentate ligaments. They have a higher incidence in women and generally affect middle-aged people. They are associated with neurofibromatosis type 2 as well as a history of radiation therapy for unrelated pathologies. They most commonly occupy the antero-lateral compartment of the spinal canal and are predominantly found in the thoracic spine. Diagnosis is often delayed due to slow growth and non-specific presenting complaints. Symptoms of neurologic compression develop when a critical degree of stenosis is reached and are characterized by gait, sensory, and sphincter disturbances. The diagnostic imaging modality of choice is MRI with and without gadolinium, which classically demonstrates a pathognomonic dural tail. Computed tomography imaging is also useful to assess the degree of calcification of the tumor. Surgical approach is usually posterior with laminectomy or laminoplasty. The lesion is localized with intraoperative ultrasound and the surgical microscope and microsurgical techniques are implemented for resection. Surgical outcomes are generally very good with low peri-operative morbidity and mortality and excellent neurologic recovery is typical. The tumors are histologically benign in most cases, and radical resection, including excision of the dural base, offers the highest probability of durable oncological cure. Adjunctive radiosurgery is reserved for more aggressive histological grades or recurrent lesions. Alternative chemotherapeutic options are in their infancy of development.
This chapter explores the details of five intradural extramedullary tumors of the spinal canal, including myxopapillary ependymoma (MPE), ganglioneuroma (GN), paraganglioma (PGL), malignant peripheral nerve sheath tumors (MPNST), and lipomas. While myxopapillary ependymoma, paraganglioma, and lipoma are commonly found in the intradural extramedullary space, ganglioneuroma and MPNST are extremely rare in this location and are more commonly found in other areas of the body. Intradural extramedullary tumors pose the risk of spinal cord compression and associated symptoms, such as pain, weakness, and motor and sensory dysfunction. These tumors are challenging to diagnose due to their rarity, non-specific symptoms, and radiologic similarity to other more common soft tissue tumors, with the exception of lipomas, which are more clearly identifiable and often occur concomitantly with occult spinal dysraphism. Definitive diagnosis of MPE, GN, PGL, and MPNST require histochemical and immunohistochemical assay and analysis for biomarkers, and even so, some are not correctly diagnosed until after they are resected and further analyzed. MPE, GN, PGL, and MPNST are all treated via surgical resection, while adjuvant chemotherapy and radiation for these tumors is still controversial and under investigation. Treatment for lipoma is also surgical resection. Prognosis is generally favorable for MPE, GN, PGL, and lipoma, but very poor for MPNST. This chapter outlines the clinical presentation, demographics, location, pathologic findings, treatment and prognosis, and differential diagnoses of the five tumors, and creates a comprehensive and systematic analysis of rare intradural extramedullary spinal cord tumors.
This article recounts the author's personal views and recollections of the history, conception of embryogenetic theories, application of intraoperative electrophysiology, and development of prospective treatment recommendations of several important spinal dysraphic malformations, including limited dorsal myeloschisis, dermal sinus tract, retained medullary cord, terminal myelocystocoele, and complex spinal cord lipomas.
This article shows the long-term advantage of total resection of complex spinal cord lipomas over partial resection and over non-surgical treatment for children with asymptomatic lipomas. The classification, embryogenesis, and technique of total resection of complex lipomas are described. The 20-year outcome of 315 patients who had total resection is measured by overall progression-free survival (PFS, Kaplan-Meier), and by subgroup Cox multivariate hazard analysis for the influence of four variables: lipoma type, symptoms, prior surgery, and post-operative cord-sac ratio. These results are compared to 116 patients who underwent partial resection, and to two published series of asymptomatic lipomas followed without surgery. The PFS after total resection for all lipomas is 88.1% over 20 years vs. 34.6% for partial resection at 10.5 years (p < 0.0001). The PFS for total resection of asymptomatic virgin lipomas rose to 98.8% vs. 60% and 67% for non-surgical treatment. Partial resection also compares poorly to non-surgical treatment for asymptomatic lipomas. Multivariate analyses show that a low cord-sac ratio is the only independent variable that predicts good outcome. Pre-operative profiling shows the ideal patient for total resection is a young child with a virgin asymptomatic lipoma, who, with a PFS of 99.2%, is essentially cured. The technique of total resection can be learned by any neurosurgeon. Its long-term protection against symptomatic recurrence is better than partial resection and conservative management. The surgery should be done at diagnosis, except for asymptomatic small infants in whom surgery should be postponed till 6 months to minimize morbidity.
Congenital lumbosacral lipomas can be responsible for progressive defects. The general feeling is that tethering of roots,
filum, or cord probably explains this evolution, and that untethering of these structures could prevent late deterioration.
Like the vast majority of neurosurgeons, we too have routinely and systematically operated on lumbosacral lipomas, even in
the absence of neurological deficits. This policy stemmed from our belief that spontaneous neurological deterioration was
frequent, recovery from preoperative deficits rare, and surgery both efficient and benign in nature. After 22 years of experience,
we felt that it was necessary to review our series of 291 lipomas (38 lipomas of the filum and 253 of the conus) operated
on from 1972 to 1994. To reassess the value of pro-phylactic surgery, we attempted an accurate evaluation of (1) the risk
of pathology, (2) the risks involved in surgery, (3) the postoperative outcome with respect to preoperative deficits, and
(4) the postoperative outcome in asymptomatic patients at 1 year and at maximum follow-up. Special attention was paid to 93
patients whose postoperative follow-up was more than 5 years (average 8.7, median 8, range 5–23 years). Of these 93 patients,
39 were asymptomatic preoperatively (7 with lipoma of the filum and 32 with lipoma of the conus). Lipomas of the filum and
of the conus are entirely different lesions and were studied separately. In 6 cases prenatal diagnosis had been possible.
The mean age at surgery was 6.4 years. Low back skin stigmata were present in 89.4% of cases. Preoperative neurological deficits
existed in 57% of the patients and were congenital in 22%. Clinical signs and symptoms recorded were pain in 13.3% of the
patients and/or neurological deficits affecting sphincter (52%), motor (27.6%) and sensory (22.4%) functions. Deficits were
progressive in 22.4% of cases, slowly progressive in 58.8% of these and rapidly progressive in the remaining 41.2%. In 36
patients (13.2%) the lipomas were seen to grow either subcutaneously or intraspinally. Among these patients, 21 were infants,
2 were obese adolescents, and 10 were pregnant women. The metabolism of the fat within the lipomas was studied in 11 patients
and found to be similar to that at other sites. Lipomas were associated with various other malformations, either intra- or
extraspinal. These associated anomalies were rare in the case of lipomatous filum (5.2%) but frequent with lipomas of the
conus, except for intracranial malformations (3.6%). Therapeutic objectives were spinal cord untethering and decompression,
sparing of functional neural tissue and prevention of retethering. Procedures used to achieve these goals were subtotal removal
of the lipoma, intraoperative monitoring, duroplasty, and sometimes closure of the placode. Histologically, lipomas consisted
of normal mature fat. However, 77% of them also included a wide variety of other tissues, originating from ectoderm, mesoderm,
or entoderm. This indicates that lipomas are either simple or complex teratomas. The results of the study are as follows.
(1) Surgery was easy and safe when performed for treatment of lipomas of the filum (no complications), but difficult and hazardous
in the case of lipomas of the conus (20% local, 3.9% neurological complications). (2) All types of deficit could be improved
by surgery, which was beneficial in all cases of lipoma of the filum and 50% of cases of lipoma of the conus. (3) In asymptomatic
patients long-term surgical results depended on the anatomical type of the lipoma. They were excellent in lipomas of the filum.
In lipomas of the conus they were good in the short term but eroded with time. At more than 5 years of follow-up only 53.1%
of the patients were still free of symptoms. (4) Reoperations were performed in 16 patients (5.5%), 5 (31.2%) of whom improved
postoperatively, while in 7 (43.7%) progression stopped, in 3 (18.7%) deterioration continued and in 1 (6.2%) the condition
was worse after surgery. (5) The natural history of the malformation, that is to say the risk of spontaneous aggravation,
has only been evaluated in hospital in-patients, so that the true level of risk remains unknown. This means we cannot interpret
the actuarial curve following surgery for asymptomatic lipoma of the conus. In conclusion, there are two different types of
lipoma: lipoma of the filum, for which surgery is harmless and beneficial in both the short and the long term, and lipoma
of the conus, for which surgery involves considerable risks and is of questionable benefit in the long term. This raises the
question as to whether prophylactic surgery is indicated for patients with asymptomatic lipomas of the conus, and whether
the outcome is any better than it would be if the lipoma were left to take its natural course. The lack of basic information
remains a stumbling block to management of these patients. Until this is remedied, we are unable to recommend prophylactic
surgery in patients with asymptomatic lipomas of the conus.
Inevitable deterioration due to mechanical tethering is perceived as the natural history for complex congenital spinal lipomas of the conus medullaris region, even if asymptomatic at presentation. The conventional wisdom that prophylactic surgical untethering improves outcome has been challenged recently [1, 2]. This study examines the natural history of asymptomatic un-operated children with lumbosacral lipomas (LSL) and investigates whether predictive factors herald deterioration.
Over the past decade, children presenting with complex LSL to a single clinician at Great Ormond Street Hospital (GOSH), London, UK have undergone a thorough assessment focusing on neurological and urological evaluation and MRI of the lumbosacral spine. For children deemed to be asymptomatic, conservative management has been adopted with close periodic surveillance of neurological and urological function, thus avoiding untethering surgery unless symptomatic deterioration occurs. A retrospective review identified this cohort of children asymptomatic of their LSL and their progress closely recorded.
This study suggests that the natural history of this subgroup of dysraphic patients may be more benign than hitherto considered. Conservative management with adoption of a novel surveillance policy and timely intervention only in the presence of symptomatic deterioration resulted in 71 % of this series remaining clinically asymptomatic at mean follow up period of 5.9 years (range, 1.0-19.3 years). At 10 years, the cumulative risk of deterioration determined by the Kaplan-Meier method was 40 %. Children aged <2 years, female, with presence of a transitional type of LSL and associated syrinx were independently associated with a higher risk of deterioration.
SUMMARY The notochordal-basichondrocranium relationships have been investigated in cranio- schisis occulta with encephalocoele (CSO-EN) and in cranioschisis aperta with exencephaly (CSA-EX) which represent, respectively, a minimal and a severe form of experimentally induced axial skeletal (dysraphic) disorders. Although apparently different, these two malformations are considered to represent different degrees of the same basic abnormality (mesodermal insufficiency) which affects the paraxial mesoderm early in embryonic develop- ment. Three different experimental models (vitamin A, sodium arsenate and clofibrate) have been used to induce these disorders. The administration of a single dose of each of these three agents during the primitive streak stage of embryonic development in the golden hamster resulted in a variety of axial skeletal (dysraphic) disorders, including the two mentioned above. Regardless of the teratogen used, the basichondrocranium in both CSO- EN and in CSA-EX is shorter than normal and slightly lordotic to the vertebral axis. The shortness of the basichondrocranium in these two disorders is caused mainly by the short- ness of the basioccipital. Both the shortness of the base of the skull and its lordotic or elevated position in relation to the vertebral axis are more pronounced in CSA-EX than in CSO-EN. The intracranial course of the notochord in these two axial disorders is considered to be within normal limits. However, the notochord itself is shorter than normal and depicts terminal folds which are considered to be the result of crowding. Both the shortness of the notochord and its terminal folding are also more pronounced in CSA-EX than in CSO-EN. The sole difference encountered betwesn the abnormal basichondrocraniums of these two disorders is in the severity of their common malformations (quantitative differences), but not in their type or quality. These findings give further support to the idea that these two axial skeletal disorders are not different types of malformations, but different degrees of the same basic abnormality. The CNS involvement (encephalocoele or exencephaly) is also considered to be secondary to the paraxial mesodermal insufficiency. It is believed, and supported by the present findings, that the normal development of the paraxial mesoderm is needed for the normal process of formation and subsequent elevation and closure of the neural folds. A primary paraxial insufficiency could result in the partial (encephalocoele) or the complete (exencephaly) failure of closure of the neural folds which characterizes this type of axial skeletal (dysraphic) disorder. In addition, the normal notochordal-basichondrocranium relationships have been investi- gated in a group of mammalian embryos including man, hamster, mouse, and several others gathered from the literature. The significant developmental variations of the intracranial course of the notochord, and of its relationships to the components of the basichondro- cranium, found among different mammals have been emphasized and illustrated. The 1
In a recent experimental study (Marin-Padilla & Ferm, 1965) of the teratogenic effects of vitamin A, a distinct cellular necrosis in the somites of young hamster embryos was found. This necrosis appeared at 12 h and the maximum degree of damage was reached some 24 h after the administration of the vitamin. The somite damage was considered then to be the earliest alteration induced by vitamin A which, in turn, causes disturbances in the axial mesoderm. Disturbances in the axial mesoderm could explain the vitamin A induced cranioschisis and sacral rhachischisis. The study of human cranioschisis (Marin-Padilla, 1965 b) and craniorhachischisis (Marin-Padilla, 1966) has also shown that unknown mesodermal conditions, affecting the cephalic and the axial mesoderm respectively, are the most likely underlying causes of these two malformations. Similar axial mesodermal conditions may also explain the notochordal alteration encountered in human cranioschisis (Marin-Padilla, 1966).
We herein describe the clinical progress of 42 myelodysplastic patients studied urodynamically and followed for a mean of 7.1 years. Urodynamic evaluation included urethral pressure profilometry, simultaneous determination of urethral pressure, intravesical pressure and external anal or external urethral sphincter electromyography with fluoroscopic voiding cystourethrography. Assessment of urethral function showed 36 patients (86 per cent) with an open vesical outlet and nonfunctional proximal urethra. Cystometrography revealed that 7 of 42 patients (17 per cent) had reflex detrusor activity: 4 with coordinated micturition and 3 with detrusor-sphincter dyssynergia. Thirty-five patients (83 per cent) had areflexic detrusor dysfunction: 5 with atonic detrusor response and 30 with a progressive increase in pressure with increasing volume. The intravesical pressure at the time of urethral leakage was 40 cm. water or less in 20 patients and at pressures greater than this value in 22 patients. No patient in the low pressure group had vesicoureteral reflux and only 2 showed ureteral dilatation on excretory urography. In contrast, of the patients in the higher pressure group 15 (68 per cent) showed vesicoureteral reflux and 18 (81 per cent) showed ureteral dilatation on excretory urography. Thus, a striking relationship between the urethral closure pressure and intravesical pressure at the time of urethral leakage and the clinical course in this group of myelodysplastic patients is demonstrated. Every patient with a normally closed vesical outlet was continent on intermittent catheterization and an anticholinergic agent, while only 60 per cent of patients with open bladder outlets similarly treated achieved good urinary control and none was dry. An artificial sphincter device would seem to be a reasonable method to achieve urinary control in the latter patients but the detrusor response to filling also must be considered. Detrusor hypertonia should be controlled or controllable before a sphincter augmenting device can be used safely. Treatment options for patients with high urethral closure pressures include intermittent catheterization and anticholinergic medications or a sphincter ablative procedure to decrease the outlet resistance combined with anticholinergic therapy and implantation of an artificial sphincter. However, only longer followup will determine if these therapeutic regimens will prevent upper urinary tract deterioration.
Anencephaly (cranioschisis) is the most representative example of a large heterogeneous group of developmental malformations characterized by abnormalities of the central nervous system and surrounding mesodermal structures. Many of these malformations have been known since ancient times and today many can be reproduced experimentally either by the administration of various teratogens or by mechanical means. Some of these malformations, e.g. anencephaly (cranioschisis) and complete cranio-myeloschisis (craniorhachischisis) represent the most severe abnormalities known to man; others, e.g. localized open myeloschisis (rhachischisis) and meningomyelocele (cystic rhachischisis), although compatible with life, require extensive surgical and medical management; while still others, e.g. occult spina bifida (occult rhachischisis), characterized by localized vertebral defects, often escapeclinical detection. This review does not presume to cover a complete classification of these malformations since there are many intermediate morphological variations which are difficult to classify in one or the other group. It includes, however, the most representative examples of these malformations; furthermore, it points to the extraordinary structural differences existing among them and, it indicates the extremes of severity and the extent of the defects which can occur. This communication, which deals with the analysis of only these malformations, assumes that a clear understanding of their basic defects will help to comprehend better the defects which characterize the entire group.
Formation of a precisely organized, functional tissue or organ is the culmination of a complex series of specific cellular events, usually termed morphogenesis. These events involve several common types of cell behavior, notably movement, proliferation, shape change, recognition, and adhesion. At each stage of morphogenesis of an organ or tissue, the macromolecules present in the extracellular matrix or associated with the external cell surface are important in providing structural support for and environmental signals to the cells involved. These contributions in turn exert a considerable influence on the course of morphogenesis.
This paper shows the long-term benefits of total/near-total resection of complex spinal cord lipomas and meticulous reconstruction of the neural placode, and specifically, its advantage over partial resection, and over non-surgical treatment for the subset of children with asymptomatic virgin lipomas.
The technique of total resection and placode reconstruction, together with technical nuances, are described in detail. We added 77 patients with complex lipomas to our original lipoma series published in 2009 and 2010, to a total of 315 patients who had had total or near-total resection and followed for a span of 20 years. Long-term outcome is measured by overall progression-free survival (PFS) with the Kaplan-Meier analysis, and by subgroup Cox proportional recurrence hazard analysis for the influence on outcome of 4 predictor variables of lipoma type, presence of symptoms, prior surgery, and post-operative cord-sac ratio. These results are compared to an age-matched, lesion-matched series of 116 patients who underwent partial lipoma resection over 11 years. The results for total resection is also compared to two large published series of asymptomatic lipomas followed without surgery over 9 to 10 years, to determine whether prophylactic total resection confers better long-term protection over conservative treatment for children with asymptomatic lipomas..
The PFS after total resection for all lipoma types and clinical subgroups is 88.1 % over 20 years versus 34.6 % for partial resection at 10.5 years (p < 0.0001). Culling only the asymptomatic patients with virgin (previously unoperated) lipomas, the PFS for prophylactic total resection for this subgroup rose to 98.8 % over 20 years, versus 67 % at 9 years for one group of non-surgical treatment and 60 % at 10 years for another group of conservative treatment. Our own as well as other published results of partial resection also compare poorly to non-surgical treatment for the subset of asymptomatic virgin lipomas. Multivariate subgroup analyses show that cord-sac ratio is the only independent variable that predicts outcome, with a 96.9 % PFS for ratio <30 % (loosest sac), 86.2 % for ratio between 30 and 50 %, and 78.3 % for ratio >50 % (tightest sac), and a threefold increase in recurrence hazard for high ratios (p = 0.0009). Pre-operative patient profiling using multiple correspondence analysis shows the ideal patient for total resection is a child less than 2 years old with a virgin asymptomatic lipoma, who, with a PFS of 99.2 %, is virtually cured by total resection.
Total/near-total resection of complex lipomas and complete reconstruction of the neural placode achieves far better long-term protection against symptomatic recurrence than partial resection for all lesions; and for the subset of asymptomatic virgin lipomas, also better than non-surgical treatment. Partial resection in many cases produces worse outcome than conservative treatment for asymptomatic lesions.
Formation of the caudal spinal cord in vertebrates is by secondary neurulation, which begins with mesenchyme-epithelium transformation within a pluripotential blastema called the tail bud or caudal cell mass, from thence initiating an event sequence proceeding from the condensation of mesenchyme into a solid medullary cord, intrachordal lumen formation, to eventual partial degeneration of the cavitatory medullary cord until, in human and tailless mammals, only the conus and filum remain.
We describe a secondary neurulation malformation probably representing an undegenerated medullary cord that causes tethered cord symptoms.
We present 7 patients with a robust elongated neural structure continuous from the conus and extending to the dural cul-de-sac, complete with issuing nerve roots, which, except in 2 infants, produced neurological deficits by tethering.
Intraoperative motor root and direct cord stimulation indicated that a large portion of this stout neural structure was "redundant" nonfunctional spinal cord below the true conus. Histopathology of the redundant cord resected at surgery showed a glioneuronal core with ependyma-lined lumen, nerve roots, and dorsal root ganglia, corroborating the picture of a blighted spinal cord.
We propose that these redundant spinal cords are portions of the medullary cord normally destined to regress but are here retained because of late arrest of secondary neurulation before the degenerative phase. Because programmed cell death almost certainly plays a central role during degeneration, defective apoptosis may be the underlying mechanism.
To show the long-term benefits of total and near-total resection of complex spinal cord lipomas and reconstruction of the neural placode.
We analyzed 238 patients with dorsal, transitional, and chaotic lipomas who had total resection as described in part I for overall progression-free survival probability (PFS, Kaplan-Meier analysis) over 16 years. We also analyzed subgroup proportional recurrence hazard (Cox analysis) of 6 outcome predictors of sex, lipoma type, age, preoperative symptoms, previous surgery, and postoperative cord-sac ratio. These results were compared with an age-matched, lesion-matched series of 116 patients followed for 11 years after partial lipoma resection and with the Parisian series of nonsurgical treatment.
The immediate effects of surgery were similar between total and partial resection: both achieved greater than 95% symptom stabilization or improvement rate. The neuro-urologic complication rates for the groups were also similar, 4.2% and 5.2% for total and partial resection, respectively. The combined cerebrospinal fluid leakage and wound complication rate of total resection was much lower at 2.5% than the 6.9% for partial resection, but both were better than published rates. The overall PFS for total resection was 82.8% at 16 years, comparing much more favorably with 34.6% for partial resection at 10.5 years (P < .0001). Culling only the asymptomatic patients with virgin (previously unoperated) lipomas to match the patient profile of the Parisian series, the PFS for prophylactic total resection for this subgroup increased to 98.4% at 16 years, versus 67% at 9 years for no surgery and 43.3% at 10.5 years for our own partial resection series, with a remarkable statistical difference between total and partial resection (P = .00001). Subgroup analyses showed that sex and lipoma type did not affect outcome. For the other predictor variables, while univariate analyses showed that young age, absence of symptom, and virgin lipomas correlated with better statistical PFS than older age, symptoms, and redo lipomas, these effects vanished with multivariate analyses. Cord-sac ratio stood alone as the only influential outcome predictor in multivariate analysis, with a 96.6% PFS for a low ratio of <30% and an 80.6% progression-free probability for a high ratio of >50%, and a 3-fold increase in recurrence hazard for high ratios (P = .0009). This suggested that all the individual effects of the other predictor variables could be reduced to whether a low cord-sac ratio could be achieved with total lipoma resection and placode reconstruction. Cord-sac ratio was the obvious factor that differentiated the outcomes between total and partial resection, the latter associated with a >90% chance of having a high cord-sac ratio.
Total and near-total resection of lipomas and complete reconstruction of the neural placode produced a much better long-term progression-free probability than partial resection and nonsurgical treatment. The perioperative complications for total resection were low and compared favorably with published results. A low postoperative cord-sac ratio and well-executed placode neurulation were strongly correlated with good outcome. The ideal preoperative patient profile with early disease stabilization and the best recurrence-free probability is an asymptomatic child less than 2 years without previous lipoma surgery. There are strong indications that partial resection in many cases produces worse scarring on the neural placode and worse prognosis than no surgery.
Partial resection of complex spinal cord lipomas is associated with a high rate of symptomatic recurrence caused by retethering, presumably promoted by a tight content-container relationship between the spinal cord and the dural sac, and incomplete detachment of the terminal neural placode from residual lipoma. Since 1991, we have performed more than 250 total/near-total resections of complex lipomas with radical reconstruction of the neural placodes. Sixteen years of follow-up have proven the long-term benefits of this technique. Part I of this series introduces our technique of total resection and reports the immediate surgical results. Part II will analyze the long-term outcomes of both total and partial resection and identify the factors affecting outcome.
From 1991 to 2006, 238 patients (age range, 2 months-72 years) with dorsal, transitional, and chaotic lipomas underwent total or near-total lipoma resection and radical placode reconstruction. Eighty-four percent of the patients were children younger than 18 years and 16% were adults. The technique consisted of wide bony exposure, complete unhinging of the lateral adhesions of the lipoma-placode assembly from the inner dura, untethering of the terminal conus, radical resection of the fat off the neural plate along a white fibrous plane at the cord-lipoma interface, meticulous pia-to-pia neurulation of the supple neural placode with microsutures, and expansile duraplasty with a bovine pericardial graft. Elaborate electrophysiological monitoring was used.
Three postoperative observations concern us. The first is that of the 238 patients, 138 (58%) had no residual fat on postoperative magnetic resonance imaging; 81 patients (36%) had less than 20 mm3 of residual fat, the majority of which were small bits enclosed by neurulation; and 19 patients (8%), mainly of the chaotic lipoma group, had more than 20 mm of fat. There are no significant differences in the amount of residual fat among lipoma types, but redo lipomas are more likely than virgin (previously unoperated on) lipomas to have residual fat by a factor of 2 (P = 0.0214). The second concern is that the state of the reconstructed placode is objectively measured by the cord-sac ratio, obtained by dividing the sagittal diameter of the reconstructed neural tube by the sagittal diameter of the thecal sac. A total of 162 patients (68%) had cord-sac ratios less than 30% (low), 61 (25.6%) had ratios between 30% and 50% (medium), and only 15 (6.3%) had high ratios of more than 50%. Seventy-four percent of patients with virgin lipomas had low cord-sac ratios compared with 56.3% in the redo lipoma patients. The overall distribution of cord-sac ratio is significantly different between redo and virgin lipomas (P = 0.00376) but not among lipoma types. Finally, the incidence of combined neurological and urological complications was 4.2%. The combined cerebrospinal fluid leak and wound infection/dehiscence incidence was 2.5%. Both sets of surgical morbidity compared favorably with the published rates reported for partial resection.
Total/near-total resection of spinal cord lipomas and complete reconstruction of the neural placode can be achieved with low surgical morbidity and a high yield of agreeable postoperative cord-sac relationship. Some large rambling transitional lipomas and most chaotic lipomas are the most difficult lesions to resect and tend to have less favorable results on postresection magnetic resonance imaging.
The clinical course of 42 children with lipomatous lesions of the lower spine is reviewed. Good neurological exam, IVP and myelography are considered essential components of the preoperative studies. The surgical aim is to free all intra- to extradural adhesions with dural grafting, if necessary. The results suggest that early corrective surgery within the first few weeks to months of life is the most satisfactory approach to preserving normal neurological and urological function in these children. 88% of children not operated on early developed progressive loss of neurological function and while delayed surgery frequently stopped progression of the disease it rarely returned the children to a normal state.
A documented scheme of the early development of the human vertebrae is presented. It is based on (1) reports of workers who personally studied staged human embryos, and (2) personal observations and confirmations. The necessity of studying staged embryos in order to determine the precise sequence of developmental events is stressed.
Tail bud formation was studied in chick embryos by light and electron microscopy. The caudal part of the neural groove at stage 11 is flanked by widely separated neural folds and merges posteriorly with the shallow primitive groove. The neural groove and primitive streak partially overlap. The depth of the neural groove gradually decreases antero-posteriorly within this overlap zone while the dorso-ventral thickness of the streak progressively increases. The anterior end of the streak begins to form a spherical accumulation of mesenchymal cells, the incipient tail bud, concomitant with closure of the posterior neuropore. Formation of the posterior body fold results in consolidation of the remainder of the streak into the definitive tail bud. The overlap zone between neural groove and primitive streak is retained as the tail bud forms. Thus the posterior end of the neural tube and anterior end of the tail bud overlap. The latter undergoes cavitation to form the ventral part of the spinal cord within this overlap region.The tail bud is initially continuous with an overlying, flattened layer of ectoderm and an underlying, columnar layer of endoderm. A bilaminar ectodermal epithelium forms directly above the developing neural tube as the dorsal portion of the tail bud undergoes cavitation. Most of the endodermal cells are displaced from the ventral surface of the tail bud by the posterior body fold and condensed into a disk-shaped region which ultimately gives rise to tail gut.
31 children with spina bifida occulta who have presented with back pain, scoliosis, a progressive neurological deficit involving lower limbs or a neurogenic bladder have been found to have a tethered spinal cord. Release of the tethered spinal cord has always relieved pain, frequently occrected a progressive scoliosis, and arrested or improved neurogenic foot deformities as well as neurogenic bladder.
From 1986 to 1991, 12 boys and 23 girls underwent surgery for lipomyelomeningocele removal. Of these patients 29 were 15 months old or younger (average age 3 months), while 6 were 4.5 to 19 years old (average age 10 years). Preoperative and postoperative urodynamic studies, including external urethral sphincter electromyography, were done on everyone. All 29 infants had a cutaneous lesion overlying the lower back and 14 had an abnormal neurological examination. Preoperative urodynamic studies were abnormal in 11 patients, consisting of an upper motor neuron lesion in 6, and a mixed upper and lower motor neuron lesion in 5. Postoperatively, 10 of 14 children with an abnormal neurological examination improved, while 9 of 11 with abnormal lower urinary tract function normalized. In 1 of 18 children (6%) with normal preoperative urodynamic studies detrusor-sphincter dyssynergia developed postoperatively. In all 6 older children urinary incontinence developed, and this led to the diagnosis. Everyone had an abnormal neurological examination and abnormal preoperative urodynamic studies. One child had a lower motor neuron lesion, and 5 had a mixed upper and lower motor neuron lesion. Postoperatively, the neurological examination improved in only 1 patient (16%), and the urological symptoms and urodynamic findings improved in another child. Lipomyelomeningocele has a progressive effect on lower spinal cord function because infants tend to present with fewer urinary manifestations and physical findings than older children. Individuals who escape early detection tend to have a more subtle cutaneous abnormality. As a result, older children are more likely to present with urological and neurological complaints. Surgical correction in infancy provides a degree of reversibility not seen in older children. It is imperative that early identification, evaluation and treatment be undertaken to prevent this progression and permanency of neurological changes and urinary dysfunction.
The medical records of patients at Children's Hospital and Medical Center treated for lipomyelomeningocele repair were reviewed to assess the long-term outcome of surgery. In total, 108 children were cared for between 1952 and 1987, and long-term data are available for 80 of 96 children who underwent surgery. Cutaneous manifestations and associated malformations were common. Surgical repair was performed at ages 1 week to 17 years; there was no operative mortality. Thirty-five of 38 children with normal preoperative examination were without deficits on long-term follow-up review. Bowel and bladder paralysis was present in 42 children and did not recover after release of cord tethering. Eleven children had return of symptoms and were reexplored 3 to 8 years after initial surgery. Surgical repair with release of cord tethering at the time of diagnosis is advocated, regardless of patient age.
The authors report on a series of 26 children with spina bifida occulta in combination with intraspinal lipoma and clinical signs of tethered cord syndrome. The age of the children at presentation ranged from 1 month to 12 years. The typical signs and symptoms consisted of skin lesions in the lumbar-sacral region, neurogenic foot deformities, and bladder and bowel disturbances.
The diagnosis was confirmed by neuroradiological investigations including lumbar myelography, computerized tomography, and only recently magnetic resonance imaging. Indications for surgery were based on the radiological evidence of intraspinal lipoma and tethered cord and especially on the clinical signs of neurological deterioration.
The results of the operative treatment are presented and the role of surgery before onset of symptoms as well as during the symptom-free interval is discussed.
Vesical and urethral function are closely controlled by neural activity, both reflex and volitional. Relatively subtle abnormalities have serious consequences. Understanding of the natural history of neurogenic vesical dysfunction has improved over the past few years and is summarized in this review article.
Twenty-four embryos of stage 12 (26 days) were studied in detail and graphic reconstructions of five of them were prepared. The characteristic features of this stage are 21–29 pairs of somites, incipient or complete closure of the caudal neuropore, and the appearance of upper limb buds. The caudal neuropore closes during stage 12, generally when 25 somititc pairs are present. The site of final closure is at the level of future somite 31, which corresponds to the second sacral vertebral level. Non-closure of the neuropore may be important in the genesis of spina bifida aperta at low levels. The primitive streak probably persists until the caudal neuropore closes, when it is replaced by the caudal eminence or end-bud (Endwulst oder Rumpfknospe). The caudal eminence, which appears at stage 9, gives rise inter alia to hindgut, notochord, caudal somites, and the neural cord. The material for somites 30–34 (which appear in stage 13) is laid down during stage 12, and its absence would be expected to result in sacral agenesis. Aplasia of the caudal eminence results in cloacal deficiency and various degrees of symmelia.
The junction of primary and secondary development (primäre und sekundäre Körperentwicklung) is probably at the site of final closure of the caudal neuropore. Secondary neurulation begins during stage 12. The cavity of the already formed spinal cord extends into the neural cord, and isolated spaces are not found within the neural cord. Primary and secondary neurulation are probably coextensive with primary and secondary development of the body, respectively. The telencephalon medium has enlarged two mesencephalic segments (M1 and M2) are distinguishable, and rhombomere 4 is reduced. The sulcus limitans is detectable in the spinal cord and hindbrain (RhD), and in the mesencephalon and diencephalon, where it extends as far rostrally as the optic sulcus in D1. A marginal layer is appearing in the rhombencephalon and mesencephalon. The first nerve fibres are differentiating, chiefly within the hindbrain (from the nucleus of the lateral longitudinal tract). Optic neural crest is at its maximum, and the otic vesicle is giving crest cells to ganglion 7/8. Neural crest continues to develop in the brain and contributes to cranial ganglia 5, 7/8, and 10/11. The spinal crest extends as far caudally as somites 18–19 but shows no subdivision into ganglia yet. Placodal contribution to the trigeminal ganglion is not certain at stage 12. Such a contribution to ganglion 7/8 is not unlikely. Involvement of neural crest in the formation of the derivatives of pharyngeal arches 1 and 2 is possible but has not yet been confirmed in the human embryo.
Ninety-seven children with lipomyelomeningoceles were operated on at the Hospital for Sick Children between January, 1960, and December, 1982. The most common factor that caused these patients to seek help was the cosmetic effect of the mass on their back. However, 22 patients had urinary incontinence and 15 patients had a deformed or weak leg. Sixty of the 97 patients were female and 37 were male. The patients presented for treatment between 6 days and 18 1/2 years of age with a median age of 7 1/2 months. Fifty-six patients presented before the age of 6 months and 35 of these were perfectly normal at the time of presentation. On the other hand, of the 41 patients who were brought for treatment after the age of 6 months, only 12 were normal prior to surgery. When patients were appropriately treated at an early age, with their spinal cords untethered and their dura securely closed with a dural graft, then they remained unchanged neurologically or even improved. However, when treatment was delayed or not done appropriately then they were left with significant neurological sequelae. Lipomyelomeningoceles are serious lesions which without appropriate therapy can result in gross impairment of neurological function.
Extracellular and cell-coat complex carbohydrates play a major role in critical cellular functions, e.g., cell recognition and cell-to-cell adherence, which are involved in neurulation. To date, available evidence suggests that neurulation is a combination of intercellular and extracellular biochemical and morphological events which are under the direction of the genome. To define the carbohydrate components that are essential to neurulation, normal C-57 and abnormal splotch (Sp/Sp) mouse embryos were studied using fluorescein-labeled lectins and computer-aided microspectrophotometric analysis of hyaluronate lyase and chondroitin ABC lyase-sensitive Alcian blue staining. Preliminary results of these studies indicate that the neuroepithelium of the splotch Sp/Sp mutant, a genetic model of a primary neural tube defect, is characterized by alterations in the type and amount of glycoconjugates and in the concentration of individual glycosaminoglycans. This review of mammalian neurulation discusses the importance of complex carbohydrates on the cell surface of the neuroepithelium of the closing neural fold.
We report a case of symptomless diastematomyelia with a bony septum discovered at post-mortem in a woman aged 64 years. It is clearly shown that this condition can exist without interfering with the function of the spinal cord and the implications of this in relation to other anomalies of the spinal cord are discussed. Our conclusion is that there can be no such entity as a tight filum terminale giving rise to symptoms in the absence of some other associated lesion.
The distinction of sacral roots and conus medullaris from lipoma, fibrous adhesions, and an abnormally thickened filum terminale can be difficult during operations on certain complicated dysraphic lesions. We describe a simple, noninvasive method of monitoring external anal sphincter "squeeze pressure" by means of an elongated, fluid-filled, polyethylene anal balloon connected to a pressure transducer. Cutaneous electrocardiographic (ECG) leads on both hips register the stimulus artifact from a monopolar nerve stimulator. The simultaneous display on the oscilloscope screen of the stimulus artifact and the resultant pressure response form an electromechanical coupling that allows the operator to identify a faulty stimulator probe and to distinguish true stimulus-induced external anal sphincter activity from spontaneous rhythmic contractions of the internal anal sphincter. Unilateral stimulation of the S-2, S-3, and S-4 roots generates tall pressure spikes between 40 and 75 torr in peak amplitudes, whereas S-1 and L-5 stimulation produces a stimulus artifact on the ECG but either no pressure response or a mere "ripple wave" of less than 7 torr. During operations on 11 patients with various dysraphic lesions, the S-2, S-3, and S-4 roots were identified easily and preserved, and the caudal extent of functioning neurons was localized within coni grossly distorted by intramedullary lipoma or chronic tethering. We prefer the anal sphincter pressure monitor to anal sphincter electromyography because of its simplicity, the inexpensive equipment, and its noise-free display that is virtually unaffected by other electronic systems in the operating room.
Ten patients with ages ranging from 4 weeks to 21 years presented with a subcutaneous lumbosacral mass noted at birth. After spinal high resolution ultrasonography or computed tomography to determine the extent of neural involvement and the length of the tumor mass in the spinal canal, the patients underwent operation. Rectal electromyographic continuous monitoring was used in all for assessment of the S-2 and S-3 function during dissection. Carbon dioxide laser microneurosurgery was used in all operations. Radiating energy was used for the subcutaneous mass removal (40 to 60 W), the intracanalicular dissection (1 to 5 W), and the intraconus dissection (1 to 3 W). A radical removal was obtained in all. Postoperative cerebrospinal fluid fistula occurred in 1 patient and was successfully treated. Wound dehiscence that healed with secondary closure occurred in 2 patients. Would infection that required treatment with systemic antibiotics and topical therapy occurred in 1 patient. Paraplegia occurred in 1 patient. This was the single very significant complication of this series. It was thought to have occurred because of the polymer used to seal the tenuous dura mater at the time of closure. We conclude that, with carbon dioxide laser microneurosurgery, the lipomatous tumors can be removed safely from the neural structures of the conus and cauda.
The histological and ultrastructural features of secondary neurulation in C57BL/6 mouse embryos were examined as a first step in the analysis of how this process occurs in mammalian embryos. Secondary neurulation involves two major events in mouse embryos: (1) formation of the medullary rosette (9.5- to 10-day embryos) or plate (11- to 12-day embryos), and (2) cavitation. These two events occur simultaneously. The medullary rosette consists of elongated tail bud cells, radially arranged around a central lumen formed by cavitation. The secondary portion of the neural tube forms in 9.5- to 10-day embryos by progressive enlargement of the central lumen and addition (by cell recruitment or mitosis) of tail bud cells to the rosette. The medullary plate likewise consists of elongated tail bud cells, but these cells do not surround a central cavity. Instead, cells of the medullary plate extend ventrad from the basal aspect of the dorsal surface ectoderm to a slit-like cavity formed by cavitation. Formation of the secondary neural tube occurs in 11- to 12-day embryos, principally by the recruitment of more lateral and ventral tail bud cells into the medullary plate. Free cells and cellular debris are frequently encountered in the forming lumen of the secondary neural tube, but cells exhibiting signs of necrosis were absent in cavitating regions. Numerous small intercellular junctions form at the inner ( juxtaluminal ) ends of tail bud cells as the medullary rosette or plate is forming and cavitation is occurring. These observations suggest that cavitation per se (i.e., formation of a lumen) during secondary neurulation is a relatively passive phenomenon, which results principally from neighboring cells becoming polarized apicobasally and incorporated into a primitive neuroepithelium. The latter constitutes the walls of the forming secondary neural tube.
Day 9 rat embryos were cultured during the period of cranial neurulation in medium containing 1 mm beta-d-xyloside, a substance which inhibits proteoglycan synthesis while stimulating the synthesis of free chains of chondroitin sulphate. The purpose of this investigation was to elucidate the morphogenetic role of chondroitin sulphate, a component of the neuroepithelial basement membrane and other extracellular regions, and to discover whether it was present in the form of proteoglycan. The histochemical results indicated a great reduction in chondroitin/chondroitin sulphate and in heparan sulphate in the neuroepithelial basement membrane and elsewhere, in beta-D-xyloside-cultured embryos. Ultrastructural studies showed an effect on the structural integrity of the neuroepithelium, with breaks in the basement membrane and abnormal form of apical microfilament bundles. These observations were correlated morphogenetically with failure of the convex neural folds to be converted to flat-concave structures, and to change their epithelial organization from columnar to pseudostratified. Neural crest cell migration was slightly retarded but apparently normal. The results are interpreted as indicating that the sulphated glycosaminoglycans, chondroitin/chondroitin sulphate and heparan sulphate, are present in the form of proteoglycan in the neuroepithelial basement membrane and elsewhere in the cranial region of day 9/day 10 rat embryos, and that they have a morphogenetic function during cranial neurulation.
The often extensive nature of intraspinal lipomas and their complex relationship to neural elements can make spinal cord untethering difficult to achieve. Based on anatomic observations at operation, we have adopted a systematic surgical approach which permits untethering with minimal risk of injury to nervous tissue. By considering the site of attachment of lipoma to cord and the position of the posterior nerve roots in relationship to the mass, the location of neural elements can be predicted. We have used this approach in 14 recently operated cases. Our experience corroborates the views of others that the high incidence of progressive neurologic deficits in these patients warrants prophylactic surgical intervention.
Patients with tethered cord syndrome (TCS) rarely have symptomatic onset in adulthood. Twenty-three adult patients with TCS were studied with respect to the clinical, radiological, and pathological features of this syndrome. Specific circumstances involving either additional tugging of the already tight conus, narrowing of the spinal canal, or direct trauma to the back or buttocks precipitated symptomatic onset in 60% of patients. Diffuse and non-dermatomal leg pain, often referred to the anorectal region, was the most common presenting symptom. Progressive sensorimotor deficits in the lower extremities as well as bladder and bowel dysfunction were also common findings; but, unlike TCS in children, progressive foot and spinal deformities were not seen. As in TCS with onset in childhood, the most common tethering lesions were thickened filum, intradural lipoma, and fibrous adhesions. The degree of cord traction, rather than the type or distribution of the tethering lesions, probably determines the age of symptom onset: less severe traction remains asymptomatic in childhood but results in neurological dysfunction in later life due to repeated tugging of the conus during natural head and neck flexion, or when abnormal tension is aggravated by trauma or spondylotic canal stenosis. Metrizamide myelography revealed the diagnosis of tethered conus in most cases, but the addition of computerized tomographic imaging provided valuable structural details concerning the tethering lesion. The surgical outcome was gratifying in relation to pain and motor weakness but disappointing in the resolution of bowel and bladder dysfunction. Early diagnosis and adequate release of the tethered conus are the keys to successful management.
The administration of a single dose of vitamin A to pregnant hamsters, early during the morning of their 8th day of gestation, induces types I and II Arnold--Chiari malformation (ACM), as well as various types of axial skeletal-dysraphic disorders known to be associated with the human disease. This new model provides a means of carrying comparative studies between the axial skeletal defects and neurological anomalies of this complex developmental malformation with those which characterize the other induced disorders related to it. Study of this experimental model has demonstrated that the basichondrocranium of fetuses with ACM is shorter than normal and slightly elevated (lordotic) in relation to the axis of the vertebral column. The shortness of the basichondrocranium of these fetuses is caused by the underdevelopment of the occipital bone specially noticeable in its basal component (basioccipital). This basic defect has resulted in a short and small posterior cerebral fossa which is inadequate to contain the developing nervous structures of that region. The developing cerebellum is displaced downward to an anomalous position just above the foramen magnum; and, the developing medulla is compressed or crowded into the small posterior cerebral fossa of affected fetuses. The lordotic elevation of the basichondrocranium is also responsible for the reduction of the pontine flexure and the increased angle of the cervical flexure of the hindbrain found in these fetuses. All of these neurological anomalies, which are characteristic and diagnostic of clinical ACm as well, are considered here to be secondary to the axial skeletal defects rather than primary abnormalities, as is generally believed. The peculiar type of protrusion of the odontoid process into the cranial cavity found in fetuses with ACM, as well as in those with cranioschisis aperta and occulta, is also considered to be caused by the slight depression of the underdeveloped basioccipital and therefore, comparable to the so-called basilar impression often described in clinical ACM. This study has emphasized various developmental features which are closely related with the morphogenesis of ACM, including: the somitic origin of the occipital bone, and the late growth of the cerebellum which is predominantly postnatal in almost all experimental animals. It has been pointed out that some developmental defects involving the occipital bone and the caudal vertebral column, such as those which characterize ACM type II, may be more closely related than previously recognized. It has been also pointed out that the so-called cerebellar herniation into the cervical spinal canal described in the human disease represents a late addition to this disorder which is related to the relatively late growth of the cerebellum...
The structural organization of experimentally induced encephaloceles has been studied with both light and electron microscopy to ascertain the nature and origin of this type of axial dysraphic disorder. Three different experimental models (vitamin A, sodium arsenate and clofibrate) have been used to induce encephaloceles in hamster embryos. Regardless of the teratogen used, the induced encephaloceles are morphologically similar types of defects. An encephalocele is necessarily accompanied by a defect in the cranial vault (cranioschisis occulta) which is considered to be the result of an incomplete or faulty closure of the membranous neurocranium at the level of the defect. In addition, the basichondrocranium of these affected embryos is shorter than normal and lordotic to the axis of the vertebral column. The shortness of the base of the skull in these experimental encephaloceles is considered to be the result of an early mesodermal insufficiency resulting in a reduction in the number of para-axial mesodermal cells. The experimental encephalocele consists of a herniated portion of the mesencephalic roof through the defect of the cranial vault. It is usually located in the mid-line and posterior to the pineal invagination. The present study has demonstrated a central zone, in all encephaloceles, in which the neuroectoderm is fenestrated, suggesting an incomplete or faulty closure of the neural tube at that level. The surface ectoderm and small amount of hypoplastic mesodermal tissue are closed above the neural tube defect. Through the gaps formed between the fenestrated lamina of neuroectodermal cells, neuronal processes (predominantly growing axons) and some glial elements escape and enter into the ventricular cavity (cerebral aqueduct). Through these gaps the neuronal and glial processes also come in contact with the collagen and the mesodermal tissue which surrounds the neural tube. These gaps represent, therefore, microscopic meningoceles. Growing neuronal and glial processes of the developing mesencephalic centers when they arrive at the central zone of the encephalocele, penetrate directly into the ventricle and the surrounding mesodermal tissue through these gaps. In view of these observations, a new hypothesis concerning the morphogenesis of encephaloceles is advanced in this study. This new hypothesis proposes that the encephalocele is only one component of a complex type of axial dysraphic disorder which also involves the formation of the membranous neurocranium (cranioschisis occulta) and of the base of the skull (short basichondrocranium). It also proposes that a primary mesodermal insufficiency which could explain all these developmental abnormalities is the fundamental defect in this type of axial dysraphic disorder. A primary mesodermal insufficiency (reduction of the number of available para-axial mesodermal cells) could result in: (a) longitudinal growth impairment of the affected region of the axial skeleton resulting in its shortness; (b) growth impairment of the formation and progressive elevation of the neural folds necessary for their apposition and eventual closure, resulting in complete or incomplete (faulty) closure of all or only some of its components; (c) growth impairment of the cephalic dorsal mesoderm resulting in complete (schisis) or partial (lacunae) failure of closure of the membranous neurocranium; and (d) growth impairment of somites resulting in segmental abnormalities. All of these developmental abnormalities are found and characterize the experimental encephaloceles studied here. The hypothesis further proposes that encephaloceles are not primary malformations of the nervous tissue (neural tube) as is generally believed, but secondary developmental defects resulting from an incomplete or faulty closure of the neuroectoderm of the neural folds caused by an insufficient amount of supporting mesodermal tissue which is primarily affected.
Mouse embryo neurulae were exposed in vitro to phospholipase C to examine the role of carbohydrate-rich extracellular material (ECM) during neurulation. Exposure of embryos to this agent for 12 h resulted in failure of closure of the neural tube. Ultrastructural examination revealed an absence of ECM from regions of the neural tube which failed to close.
Lipomyelomeningocele is one of the more common forms of occult spinal dysraphism seen in clinical practice. It is now universally accepted that prophylactic surgery is indicated in most cases, but areas of controversy remain. These include the diagnosis and management of retethering, the value of intraoperative physiological monitoring, and indications for surgery in stable adults and when the conus is in the normal position.
Human tails have been described intermittently in the literature, typically as isolated cases with varying forms of malformation. Attempts have been made to differentiate "true" tails from "tail-like" appearances. Unless identified, underlying occult spinal disorders, mass effect, and/or tethering of the spinal cord may lead to progressive neurologic damage. We report three patients with "tails" and the associated spinal anomalies.
Eighteen children under the age of 1 year underwent surgery for lipomeningocele at our institution between 1983 and 1991. All the patients had neurologic exams and urodynamic studies (UDS) including a cystometrogram and electromyography of the external urethral sphincter pre- and postoperatively. The surgical procedure performed included an untethering of the spinal cord, laser debulking of the lipoma and placement of a dural graft. All the infants presented with a lesion on their back. Two of 10 infants with a normal neurological exam had abnormal UDS preoperatively. Early surgery normalized abnormal preoperative UDS in 5 of 6 (83%) infants with abnormal UDS. Moreover, 3 of 8 (38%) infants with an abnormal neurological exam preoperatively improved after surgery and none worsened. These observations suggest that abnormal urinary tract function in infants with lipomeningocele may be reversible with early prophylactic surgery.
We assessed the normal movement of the lumbar spinal cord using phase-contrast MR imaging, and also the movement of the spinal cord in patients with spinal lipoma pre- and postoperatively. Phase-contrast MR imaging proved to be a valuable tool in this context.