[Show abstract][Hide abstract] ABSTRACT: A clinicobiomechanical study.
To clarify the clinicobiomechanical characteristics of a segment with lumbar degenerative spondylolisthesis (LDS) using an original intraoperative measurement system.
Although radiographical evaluation of LDS is extensively performed, the diagnosis of segmental instability remains controversial. The intraoperative measurement system used in this study is the first clinically available system that performs cyclic flexion-extension displacement of the segment with all ligamentous structures intact and can determine both the stiffness (N/mm) and neutral zone (NZ, [mm/N]).
Forty-eight patients with LDS (males/females = 19/29, 68.5 yr; group D) were compared with 48 patients with lumbar spinal stenosis without LDS (males/females = 33/15, 64.8 yr, group N) in terms of symptoms, radiological, and biomechanical results. Instability was defined as a segment with NZ more than 2 mm. Symptoms (36-Item Short Form Health Survey), radiographical findings (radiographs, magnetic resonance images, computed tomographic scans), stiffness, NZ, and frequency of instability were also compared. Risk factors for instability were analyzed by multivariate logistic regression with a forward stepwise procedure.
None of the physical function categories or radiological findings of 36-Item Short Form Health Survey and low back pain (visual analogue scale) differed significantly between the groups. Although NZ was significantly greater in group D (1.97) than in group N (1.73) (P < 0.05), the frequency of instability did not differ significantly between groups. Facet opening (odds ratio, 11.0; P < 0.01) and facet type (odds ratio, 6.0; P < 0.05) were significant risk factors for instability.
Neither the symptoms nor the frequency of instability differed significantly between groups. The radiological findings of spondylolisthesis did not indicate instability, but facet opening and sagittally oriented facets were indicative of instability. The results of this study demonstrated that LDS is not always unstable in the measurement setting, suggesting that the instability of LDS can stabilize spontaneously during the natural course.
[Show abstract][Hide abstract] ABSTRACT: OBJECTIVE: To compare the diagnostic efficacy of recumbent magnetic resonance imaging (MRI), computed tomography myelography (CTM), and myelography, with regard to indications for surgery for lumbar stenosis. BACKGROUND DATA: In patients with lumbar spinal stenosis-like disorders, small compressions are sometimes observed in magnetic resonance images acquired in the recumbent position, leading to potential misdiagnosis. Few prospective studies have compared the diagnostic accuracy of MRI, myelography, and CTM. Therefore, it is not clear whether myelography is necessary or not. METHODS: Fifty-four patients fulfilled the criteria. All patients underwent MRI, myelography, and CTM. MRI was performed with the patient in a normal recumbent position, and CTM was performed with the patients in both a recumbent and extended positions. All patients underwent surgery for lumbar spinal stenosis. Findings from visual examinations (sagittal images of MR, axial images of MR, axial reconstruction images of CTM and myelograms) were defined as compression + or -. We analyzed the sensitivity of the different examinations for diagnosis and the relationship among the types of images. RESULTS: Sensitivity was as follows: CTM 94.4 %, myelography 87.0 %, and MRI 75.9 %. In myelography, the images of 37 patients were worsened by dynamic synthesis (Dyn+). Among patients without compression on MRI, 11 showed compression on myelography. Of these 11, 8 of these patients were Dyn+, and 2 patients showed compression on myelography, but not on CTM and were Dyn+. Thus, some compression can be revealed only with myelography. CTM was more sensitive than axial MRI and showed compression in 12 patients that was not detected by axial MRI. CONCLUSION: Myelography revealed stenosis that was not detected by MRI. CTM with extension is more sensitive for detecting stenosis than MRI. Recumbent MRI cannot replace myelography or CTM in terms of dynamic findings and sensitivity.
No preview · Article · Mar 2013 · European Journal of Orthopaedic Surgery & Traumatology
[Show abstract][Hide abstract] ABSTRACT: We examined the reliability of radiological findings in predicting segmental instability in 112 patients (56 men, 56 women) with a mean age of 66.5 years (27 to 84) who had degenerative disease of the lumbar spine. They underwent intra-operative biomechanical evaluation using a new measurement system. Biomechanical instability was defined as a segment with a neutral zone > 2 mm/N. Risk factor analysis to predict instability was performed on radiographs (range of segmental movement, disc height), MRI (Thompson grade, Modic type), and on the axial CT appearance of the facet (type, opening, vacuum and the presence of osteophytes, subchondral erosion, cysts and sclerosis) using multivariate logistic regression analysis with a forward stepwise procedure. The facet type was classified as sagittally orientated, coronally orientated, anisotropic or wrapped. Stepwise multivariate regression analysis revealed that facet opening was the strongest predictor for instability (odds ratio 5.022, p = 0.009) followed by spondylolisthesis, MRI grade and subchondral sclerosis. Forward stepwise multivariate logistic regression indicated that spondylolisthesis, MRI grade, facet opening and subchondral sclerosis of the facet were risk factors. Symptoms evaluated by the Short-Form 36 and visual analogue scale showed that patients with an unstable segment were in significantly more pain than those without. Furthermore, the surgical procedures determined using the intra-operative measurement system were effective, suggesting that segmental instability influences the symptoms of lumbar degenerative disease.
No preview · Article · May 2011 · The Bone & Joint Journal
[Show abstract][Hide abstract] ABSTRACT: Retrospective clinical study.
To evaluate clinical results of patients with nontraumatic cervical lesions treated by cervical pedicle screw (PS) fixation and to discuss the surgical indications.
PS fixation provides an outstanding stability for cervical lesions with instability. This technique, however, has a potential risk of vertebral artery, spinal cord, and nerve root injuries, which may be catastrophic.
Fifty-eight patients were divided into 2 groups: patients with cervical kyphosis with vertebral destructive lesions (group D, n = 38) and those without destructive lesions (group ND, n = 20). Clinical results of the 2 groups were compared. The results of decompression and PS fixation for cervical spondylotic myelopathy (CSM) and ossification of the posterior longitudinal ligament (OPLL) in this series were also compared with those of previous laminoplasty alone in patients with CSM and OPLL.
Nape pain in group D improved in 86.7% of the patients. Overall neurologic status was improved in both groups. Bony fusion was confirmed in 100% of the cases that were alive in group D and 95% in group ND. Eight complications including 2 vertebral artery injuries occurred. The incidence of postoperative cervical complications in group ND was significantly higher than that in group D. Although PS fixation significantly corrected cervical kyphosis and maintained in both CSM and OPLL, operation time and intraoperative blood loss in cases treated by PS were significantly higher than those treated by laminoplasty alone. Improvement of nape pain and neurologic status did not differ with and without using PS fixation.
There is an indication of cervical PS fixation for destructive lesions because of a high fusion rate with improvement of nape pain. On the other hand, there is no indication in cases of typical CSM and OPLL if a potential risk of vertebral artery or nerve injury is taken into account.
[Show abstract][Hide abstract] ABSTRACT: In vivo quantitative measurement of lumbar segmental stability has not been established. The authors developed a new measurement system to determine intraoperative lumbar stability. The objective of this study was to clarify the biomechanical properties of degenerative lumbar segments by using the new method.
Twenty-two patients with a degenerative symptomatic segment were studied and their measurements compared with those obtained in normal or asymptomatic degenerative segments (Normal group). The measurement system produces cyclic flexion-extension through spinous process holders by using a computer-controlled motion generator with all ligamentous structures intact. The following biomechanical parameters were determined: stiffness, absorption energy (AE), and neutral zone (NZ). Discs with degeneration were divided into 2 groups based on magnetic resonance imaging grading: degeneration without collapse (Collapse[-]) and degeneration with collapse (Collapse[+]). Biomechanical parameters were compared among the groups. Relationships among the biomechanical parameters and age, diagnosis, or radiographic parameters were analyzed.
The mean stiffness value in the Normal group was significantly greater than that in Collapse(-) or Collapse(+) group. There was no significant difference in the average AE value among the Normal, Collapse(-), and Collapse(+) groups. The NZ in the Collapse(-) was significantly higher than in the Normal or Collapse(+) groups. Stiffness was negatively and NZ was positively correlated with age. Stiffness demonstrated a significant negative and NZ a significant positive relationship with disc height, however.
There were no significant differences in stiffness between spines in the Collapse(-) and Collapse(+) groups. The values of a more sensitive parameter, NZ, were higher in Collapse(-) than in Collapse(+) groups, demonstrating that degenerative segments with preserved disc height have a latent instability compared to segments with collapsed discs.
No preview · Article · Apr 2008 · Journal of Neurosurgery Spine
[Show abstract][Hide abstract] ABSTRACT: Retrospective analysis.
To test the hypothesis that spinal cord lesions cause postoperative upper extremity palsy.
Postoperative paresis, so-called C5 palsy, of the upper extremities is a common complication of cervical surgery. Although there are several hypotheses regarding the etiology of C5 palsy, convincing evidence with a sufficient study population, statistical analysis, and clear radiographic images illustrating the nerve root impediment has not been presented. We hypothesized that the palsy is caused by spinal cord damage following the surgical decompression performed for chronic compressive cervical disorders.
The study population comprised 857 patients with chronic cervical cord compressive lesions who underwent decompression surgery. Anterior decompression and fusion was performed in 424 cases, laminoplasty in 345 cases, and laminectomy in 88 cases. Neurologic characteristics of patients with postoperative upper extremity palsy were investigated. Relationships between the palsy, and patient sex, age, diagnosis, procedure, area of decompression, and preoperative Japanese Orthopaedic Association score were evaluated with a risk factor analysis. Radiographic examinations were performed for all palsy cases.
Postoperative upper extremity palsy occurred in 49 cases (5.7%). The common features of the palsy cases were solely chronic compressive spinal cord disorders and decompression surgery to the cord. There was no difference in the incidence of palsy among the procedures. Cervical segments beyond C5 were often disturbed with frequent multiple segment involvement. There was a tendency for spontaneous improvement of the palsy. Age, decompression area (anterior procedure), and diagnosis (ossification of the posterior longitudinal ligament) are the highest risk factors of the palsy.
The results of the present study support our hypothesis that the etiology of the palsy is a transient disturbance of the spinal cord following a decompression procedure. It appears to be caused by reperfusion after decompression of a chronic compressive lesion of the cervical cord. We recommend that physicians inform patients and surgeons of the potential risk of a spinal cord deficit after cervical decompression surgery.
[Show abstract][Hide abstract] ABSTRACT: Description of surgical technique and retrospective review of 13 cases.
To describe the surgical technique of margin-free spondylectomy and the outcome of 13 cases and to discuss the advantages and limitations of the procedure.
Recently, spondylectomy became a standard procedure by several pioneers. For extended malignant spine tumors involving pedicles or epidural space, however, performing an "en bloc" resection with a tumor-free margin remains a challenge.
Our procedure consists of a combined anterior and posterior procedure with one or two stages. In the anterior procedure, tumor vertebrae are covered by the pleura or psoas muscles as a barrier. The posterior procedure includes decompression through the intact posterior elements, coverage of the tumor with all possible soft tissue barriers, and en bloc extirpation by rotating the tumor vertebrae around the spinal cord. We performed this procedure in 13 cases: 3 chondrosarcoma, 3 giant cell tumor, 1 osteosarcoma, 1 chordoma, and 5 metastases.
Neurologic status and pain improved in all cases except asymptomatic cases. There was no local recurrence, except in 2 cases (chondrosarcoma with extirpation of 5 vertebrae, chordoma with multiple previous surgeries). Two cases of chondrosarcoma were disease-free 14 years and 13 years after surgery, respectively.
Although the best chance for a cure in extended malignant tumors of the spine is realized through wide resection, the procedure is not yet standardized. Margin-free spondylectomy is technically demanding, but the procedure can be used with a confidence as a more radical surgery for tumors extending to the epidural space and the unilateral pedicle. A key to success is the surgical technique, including a 360 degree dissection around the tumor vertebrae, instrumentation, and removal of the lesion with all possible soft tissues maintained intact to function as a barrier, like the dura mater.
[Show abstract][Hide abstract] ABSTRACT: The mechanism underlying cervical flexion myelopathy (CFM) is unclear. The authors report the results of anterior decompression and fusion (ADF) in terms of neurological status and radiographically documented status in young patients and discuss the pathophysiological mechanism of the entity.
Twelve patients underwent ADF in which autogenous iliac bone graft was placed. The fusion area was one segment in four cases, two segments in seven, and three segments in one. Neurological status, as determined by the Japanese Orthopaedic Association (JOA) score, radiographic findings, and intraoperative findings were evaluated. The mean follow-up period was 63.3 months (range 20-180 months). Grip strength was significantly improved and sensory disturbances resolved completely. Intrinsic muscle atrophy, however, persisted in all patients at the final follow-up examination. Local kyphosis in the flexed-neck position at the fusion levels was corrected by surgery. Preoperative computerized tomography myelography revealed that the cord compression index, which was calculated by anteroposterior and transverse diameters of the spinal cord, decreased to 33 +/- 6.2% in the flexed-neck position from 39.7 +/- 9.9% in the extended-neck position. The anterior dura mater-spinal cord distance decreased to 1.9 +/- 0.7 mm in the flexed-neck position from 4 +/- 1.2 mm in extended-neck position. The posterior dura mater-spinal cord distance increased to 2.5 +/- 1.1 mm in the flexed-neck position from 1.3 +/- 0.5 mm in the extended-neck position.
Postoperative neurological status was improved in terms of grip strength, sensory disturbance, and JOA score, and local kyphosis in the flexed-neck position at the fusion levels was reduced and stabilized by ADF. In most cases local kyphosis in the flexed-neck position was demonstrated at the corresponding disc level, as were cervical cord compression and decrease of the anterior wall of the dura mater-spinal cord distance in the flexed-neck position. Therefore, the contact pressure between the spinal cord and anterior structures (intact vertebral bodies and intervertebral discs) in the mobile and kyphotic segments was considered to contribute to the onset of CFM. The ADF-related improvement of the clinical symptoms, preventing kyphotic alignment in flexion and decreasing movement of the cervical spine, supports the idea of a contact pressure mechanism. Furthermore, short ADF performed only at the corresponding segments can preserve more mobile segments compared with posterior fusion. Thus, ADF should be the first choice in the treatment of CFM.
No preview · Article · Sep 2005 · Journal of Neurosurgery Spine
[Show abstract][Hide abstract] ABSTRACT: Surgery for degenerative lumbar kyphoscoliosis (DLKS) is very challenging because the curve has become rigid due to circumferential osteoarthritic changes. Therefore, a standard procedure involving correction and fusion after decompression of the nerves has not yet been established. The authors have been searching for an effective procedure that provides adequate decompression and three-dimensional (3D) correction for symptomatic DLKS. In this report they describe a new 3D correction and fusion technique involving multilevel posterior lumbar interbody fusion. They analyze the results obtained in the first 23 cases and discuss the advantages and disadvantages of the procedure. The correction effect was excellent, and compared with other instrumentation-assisted procedures, this surgery is not remarkably invasive. Although the procedure is limited in achieving normal sagittal alignment and the acceleration rate of adjacent-disc degeneration remains relatively high, it is an option for the rigid deformity characterized by DLKS.
No preview · Article · Aug 2003 · Journal of Neurosurgery
[Show abstract][Hide abstract] ABSTRACT: The objective of this study was to compare efficacy of cervical surgery for myelopathy in patients > or = 70 and < or = 60 years of age. Forty patients > or = 70 years and 50 patients < or = 60 years of age with MRI and CT proven myelopathy were neurologically assessed using the JOA score. Three operative procedures were performed: anterior spinal fusion, laminoplasty, and laminectomy. Postoperatively, patients exhibited comparable outcomes irrespective of age or operative procedure performed. The only exception was the increase in postoperative neurologic complications noted for the older individuals with greater comorbidities.
No preview · Article · Dec 2002 · Journal of Spinal Disorders & Techniques
[Show abstract][Hide abstract] ABSTRACT: Segmental neurofibromatosis is a rare disease characterized by neurofibromas with or without café au lait spots localized to one segment of the body. The majority of reported cases have had cutaneous neurofibromas, and patients with deep involvement have rarely been described. We report on two patients with deep-seated segmental plexiform neurofibromatosis and review the literature. All reviewed cases including the present two had no café au lait spots, axillary freckling, Lisch nodules, family history or malignant progression of disease. Differential diagnoses from neuro-fibromatosis 1 (von Recklinghausen disease) and malignant peripheral nerve sheath tumor are important for genetic counseling and avoiding overtreatment.
No preview · Article · Oct 2000 · Skeletal Radiology
[Show abstract][Hide abstract] ABSTRACT: Patients with cervical compression myelopathy were studied to elucidate the mechanism underlying boomerang deformity, which results from the migration of the cervical spinal cord between split laminae after laminoplasty with median splitting of the spinous processes (boomerang sign). Thirty-nine cases, comprising 25 patients with cervical spondylotic myelopathy, 8 patients with ossification of the posterior longitudinal ligament, and 6 patients with cervical disc herniation with developmental canal stenosis, were examined. The clinical and radiological findings were retrospectively compared between patients with (B group, 8 cases) and without (C group, 31 cases) boomerang sign. Moderate increase of the grade of this deformity resulted in no clinical recovery, although there was no difference in clinical recovery between the two groups. Most boomerang signs developed at the C4/5 and/or C5/6 level, where maximal posterior movement of the spinal cord was achieved. Widths between lateral hinges and between split laminae in the B group were smaller than in the C group. Flatness of the spinal cord in the B group was more severe than in the C group. In conclusion, the boomerang sign was caused by posterior movement of the spinal cord, narrower enlargement of the spinal canal and flatness of the spinal cord.
Preview · Article · May 2000 · European Spine Journal
[Show abstract][Hide abstract] ABSTRACT: Two case reports of sciatica that was considered to be caused by cervical and thoracic spinal cord compression.
To point out that sciatica can be an initial major symptom in patients with cervical or thoracic spinal cord lesions.
Usually, tract pain caused by cord compression is considered to be diffuse and does not resemble sciatica.
Medical history, physical findings, and the results of imaging studies were reviewed in one case of cervical cord tumor and one case of thoracic kyphosis.
In both cases, sciatica was the initial and major symptom. Imaging studies showed no lesion in the lumbar spine. In one patient, a cervical dumbbell tumor was found to compress the cervical cord, and in the other the spinal cord was severely compressed at the thoracic kyphosis. The sciatica disappeared immediately after decompression surgery in both cases.
Leg pain resembling sciatica can be caused by cord compression at the cervical and thoracic level. Thoracic kyphosis may be a causative factor in sciatica, in addition to spinal cord tumor and disc herniation, which have been reported previously.
[Show abstract][Hide abstract] ABSTRACT: To elucidate the involvement of NO in pain transmission in humans, we measured NO metabolites (nitrite/nitrate) in the CSF of patients with painful diseases using an NO analyzer based on the Griess method. The nitrite/nitrate levels in patients with degenerative lumbar disease (DLD), but not those with fracture or appendicitis, were significantly higher than those in an age-matched control group. The duration of pain in the DLD group was much longer than that in the fracture or appendicitis group. The nitrite/nitrate levels in the middle-aged and elderly DLD patients depended on the duration of pain. These data probably suggest that the duration of pain is critical for the elevation in nitrite/nitrate levels.
[Show abstract][Hide abstract] ABSTRACT: This is a retrospective study of the morphologic limitations of posterior decompression for ossification of the posterior longitudinal ligament in the cervical spine.
To determine the morphologic limitations of the posterior approach in the management of ossification of the posterior longitudinal ligament.
Thirty-eight patients who underwent laminoplasty by midsagittal splitting for ossification of the posterior longitudinal ligament were reviewed. Fifteen patients were included in the noncontact group, in which the spinal cord was free of the ossified lesion after posterior decompression. Twenty-three patients were included in the contact group, in which the spinal cord was not free of the ossified lesion even after posterior decompression.
The preoperative sagittal alignment of the cervical spine and preoperative maximal thickness of ossification were compared between the two groups. In addition, the morphologic limitations of posterior decompression for ossification of the posterior longitudinal ligament were investigated.
The following factors were found to contribute significantly to contact between the spinal cord and ossification of the posterior longitudinal ligament after posterior decompression: 1) lordosis of less than 10 degrees or kyphosis in the preoperative sagittal alignment, and 2) preoperative maximal thickness of ossification of more than 7 mm.
Patients who exhibit significant risk factors for continued contact of the spinal cord should be morphologically considered for anterior decompression.
[Show abstract][Hide abstract] ABSTRACT: Introduction of a new diagnostic procedure and a report on its usefulness.
To introduce a new endoscope (myeloscope) developed for the examination of the spinal canal and to present a previously unreported subarachnoid condition as a cause of paraparesis revealed by it.
In spite of the availability of advanced imaging technology, there still exists a significant number of patients with spinal diseases in whom a diagnosis cannot be made. Direct visualization of the pathologic area is required in these patients. Recent advances in fiberoptics have made this possible.
The endoscope consisted of a fiberscope with an external diameter of 0.5, 0.9, or 1.4 mm. It was inserted into the subarachnoid space in the lumbar spine and carefully advanced cranially. Since 1987, this examination has been performed on 18 patients aged 7 to 69 years who had pain or other neurologic symptoms of unknown origin.
The surface of the spinal cord, roots, properties of the arachnoid membrane, and small vessels could be observed clearly. The scope could be advanced as far as the upper cervical spine. Cotton-candy-like proliferation of fibrous tissue was identified by myeloscopy in four paraparetic patients who had clinical and radiologic features similar to those of a spinal cord herniation. The fibrous tissue beat on the spinal cord with the pulsation of the spinal fluid. Resection of the fibrous tissue with conventional surgery resulted in neurologic improvement. Complications included one case of meningitis in the early period and five cases of postspinal headache. No nerve injury was apparent.
Myeloscopy provides detailed information about the subarachnoid space and even reveals dynamic conditions that cannot be identified during open surgery or at autopsy. It will bring new concepts to the diagnosis of spinal diseases.
[Show abstract][Hide abstract] ABSTRACT: Radiologic and operative findings of intravertebral cleft in the osteoporotic spine were investigated and the pathomechanism discussed.
To clarify the pathologic features of the intravertebral cleft.
Intravertebral "vacuum" cleft is one of the common radiographic findings in the osteoporotic spine. It is thought that the cleft is a rare lesion of an ununited fracture, or pseudarthrosis. Evidential findings of the disease, however, have never been reported.
Simple bone grafting was performed in five cases (average age, 76.8 years) of thoracolumbar intravertebral cleft in osteoporotic spine in patients who had been suffering from prolonged pain of the back or leg. Preoperative radiologic evaluation using flexion-extension radiograph and magnetic resonance imaging was performed in all patients. At operation, the cleft and the components of the structure were macroscopically and microscopically observed. The fluid content in the cleft was biochemically analyzed.
In all patients, preoperative flexion-extension radiographs showed intravertebral instability at the location of the clefts that indicated gas density in three cases and water density in two cases. Magnetic resonance imaging showed that, for the most part, the cleft was low intensity on the T1-weighted image and high intensity on the T2-weighted scans, regardless of the radiographic findings. At operation, abnormal movement was observed at the cleft of the affected body, which was covered with hypertrophic membrane. The serous fluid within the cleft was aspirated before the excision of soft tissue. The thick membrane was excised and showed that the cleft was lined by smooth fibrocartilaginous tissue and the great degree of motion between the fracture ends that is consistent with the pathologic appearance of pseudarthrosis.
The unstable cleft in the affected vertebral body of the osteoporotic spine with magnetic resonance findings of low intensity on the T1-weighted scans and high intensity on the T2-weighted scans suggests that the cleft is a false joint lined by fibrocartilaginous tissue with notable movement consistent with pseudarthrosis.