[show abstract][hide abstract] ABSTRACT: The retrosigmoid approach is a work-horse approach to the cerebellopontine angle (CPA), providing access from the foremen magnum to the tentorium. Indications for this approach are variable such as resection of meningiomas, acoustic neuromas and epidermoid tumors, treatment of vascular lesions of vertebrobasilar system, vascular decompression of cranial nerves (V, VII, IX, X), cranial nerve neurectomies, and intrinsic lesions of the cerebellum and brainstem. In this video, we demonstrate the use of retrosigmoid craniotomy for resection of a large CPA meningioma, delineating all steps including positioning, mapping. The video can be found here: http://youtu.be/kISkYS16Brk .
[show abstract][hide abstract] ABSTRACT: The pupose of this study is to assess the long-term outcome and toxicity of fractionated stereotactic radiation therapy (FSRT) and stereotactic radiosurgery (SRS) for 100 vestibular schwannomas treated at a single institution. From 1993 to 2007, 104 patients underwent were treated with radiation therapy for vestibular schwannoma. Forty-eight patients received SRS, with a median prescription dose of 12.5 Gy for SRS (range 9.7-16 Gy). For FSRT, two different fraction schedules were employed: a conventional schedule (ConFSRT) of 1.8 Gy per fraction (Gy/F) for 25 or 28 fractions to a total dose of 45 or 50.4 Gy (n = 19); and a once weekly hypofractionated course (HypoFSRT) consisting of 4 Gy/F for 5 fractions to a total dose of 20 Gy (n = 37). Patients treated with FSRT had better baseline hearing, facial, and trigeminal nerve function, and were more likely to have a diagnosis of NF2. The 5-year progression free rate (PFR) was 97.0 after SRS, 90.5 % after HypoFSRT, and 100.0 % after ConFSRT (p = NS). Univariate analysis demonstrated that NF2 and larger tumor size (greater than the median) correlated with poorer local control, but prior surgical resection did not. Serviceable hearing was preserved in 60.0 % of SRS patients, 63.2 % of HypoFSRT patients, and 44.4 % of ConFSRT patients (p = 0.6). Similarly, there were no significant differences in 5-year rates of trigeminal toxicity facial nerve toxicity, vestibular dysfunction, or tinnitus. Conclusions:Equivalent 5-year PFR and toxicity rates are shown for patients with vestibular schwanoma selected for SRS, HypoFSRT, and ConFSRT after multidisciplinary evaluation. Factors correlating with tumor progression included NF2 and larger tumor size.
Journal of Neuro-Oncology 10/2013; · 3.12 Impact Factor
[show abstract][hide abstract] ABSTRACT: BACKGROUND:: Primary central nervous system posttransplantation lymphoproliferative disorder (PCNS-PTLD) is a rare complication after solid organ transplantation (SOT). With increasing rates of SOT, PCNS-PTLD incidence is increasing. OBJECTIVE:: To describe the characteristics of PCNS-PTLD patients requiring neurosurgical intervention. METHODS:: From 2000 to 2011, 10 patients with prior SOT underwent biopsy for evaluation of brain lesions and were diagnosed with PCNS-PTLD. Data collected included imaging characteristics, pathology, treatments administered, and survival outcomes. RESULTS:: All patients had kidney transplantation, and 3 had concurrent pancreas transplantation. Median age at diagnosis was 49 years, with a median of 4.5 years from SOT to diagnosis (range, 1.8-11.4 years). Presenting symptoms most often included focal neurological deficits (n = 6), although several patients had nonspecific symptoms of headache and altered mental status. Brain lesions were generally multiple (n = 7), supratentorial (n = 8), and lobar or periventricular in distribution with ring enhancement. Diagnosis was established by stereotactic (n = 4) and open surgical (n = 6) biopsy. Treatments most frequently administered included reduction of immunosuppression (n = 10), dexamethasone (n = 10), rituximab (n = 8), high-dose methotrexate (n = 3), and whole-brain radiotherapy (n = 6). Six patients remain alive without PCNS-PTLD relapse, including 4 patients who have sustained remissions beyond 2 years from diagnosis of PCNS-PTLD. Of 4 observed deaths, 1 was related to progressive PCNS-PTLD. CONCLUSION:: PCNS-PTLD must be considered in the differential diagnosis of any patient with prior SOT presenting with an intracranial lesion. Histological diagnosis with brain biopsy is imperative, given the risk for opportunistic infections that may have similar imaging findings and presentation. Prognosis is variable, although long-term survival has been reported. ABBREVIATIONS:: EBER, Epstein-Barr virus--encoded RNAEBV, Epstein-Barr virusPCNS-PTLD, primary central nervous system posttransplantation lymphoproliferative disorderSOT, solid organ transplantation.
[show abstract][hide abstract] ABSTRACT: Background Laminoplasty in the case of intramedullary spinal tumor requires care to avoid neurologic injury. The harmonic bone scalpel provides a method of laminoplasty that can be done safely and quickly for this and other indications.Patients Five cases are presented, each of which required operative intervention, namely laminoplasty. The pathologies presented are one cervical intramedullary tumor, one thoracic intramedullary spinal mass, one lumbar extramedullary intradural tumor, and two cases of multiple lower brachial plexus nerve root avulsions requiring dorsal root entry zone (DREZ) lesion.Results These five patients underwent laminoplasty for either tumor resection or DREZ lesion. The laminotomies were performed using the BoneScalpel™ (Misonix Inc., Farmingdale, NY, USA), which is a harmonic bone scalpel instrument. This obviated the need to place any instrument under the intact lamina. Kerrison punches and various instruments were still used, but for purposes other than the bony removal of the laminoplasty.Conclusion These cases demonstrate that the BoneScalpel™ can be used to facilitate the laminar cuts while still allowing a safe and effective operation, even in cases as delicate as an intramedullary thoracic spinal cord tumor. The mechanism of action of the harmonic bone scalpel allows osteotomies without cutting or penetrating soft tissue and also leaves minimal bony defect.
Journal of neurological surgery. Part A, Central European neurosurgery. 03/2013;
[show abstract][hide abstract] ABSTRACT: True hemodynamic assessment of the posterior communicating artery (PComA) by preoperative angiography in terms of its perforators and configuration (adult vs. fetal vs. transitional) can be challenging in the surgical treatment of aneurysms involving the PComA, posterior cerebral artery, and basilar artery. Indocyanine green videoangiography (ICG-VA) is a widely accepted new technique in the surgical treatment of intracranial aneurysms to assess the patency of the parent artery, branches, and residual flow within the aneurysm after clipping.
Here we report two cases in which ICG-VA was utilized to assess either the direction of flow in the PComA or preservation of the PComA perforators with temporary clip application before dividing the PComA.
Our experience is that ICG-VA can be used to assess the main trunk, and perforating branches of the PComA providing real-time, dynamic intraoperative information of the surgical field. Therefore we suggest that ICG-VA may increase the safety of surgical treatment of aneurysm involving PComA.
[show abstract][hide abstract] ABSTRACT: Isolated Blastomyces dermatitidis infection of the central nervous system is an uncommonly encountered entity. If left untreated it can be fatal; thus accurate diagnosis in a timely manner is critical. A 37-year-old white male presented with a severe headache. An MRI scan revealed a rightsided enhancing cerebellopontine angle mass with extension into the internal acoustic canal and diffuse basilar enhancement. After thorough assessment of the patient, an open surgical biopsy of the lesion was performed for pathological evaluation. The biopsy demonstrated broadbased budding yeasts. The cerebrospinal fluid antigen enzyme immunoassay (EIA) (MVista®) for Blastomyces dermatitidis was also positive with a level of 4.28 EIA units.
[show abstract][hide abstract] ABSTRACT: INTRODUCTION: Indocyanine green video angiography (ICG-VA) has been recently introduced into neurovascular surgery and gained a role in assessing vessel patency and obliteration of intracranial aneurysms (IA) after clipping. Although its correlation with intra-postoperative angiography was demonstrated in previous studies, difficulties in evaluating aneurysm obliteration have not been reported. We report reliability and accuracy of ICG-VA in 109 clipped aneurysms with attention given to five cases in which ICG-VA evaluation resulted in false indication that aneurysms were secure in terms of complete obliteration. MATERIALS AND METHODS: A retrospective chart review was performed of IAs surgically treated by a single surgeon from January 2009. In all cases, aneurysm obliteration was confirmed by a combination of microdoppler ultrasonography (MUSG), ICG-VA, and post-operative angiography. RESULTS: ICG-VA appropriately assessed vessel patency and aneurysm obliteration in 93.5% of aneurysms clipped. In four cases (3.6%), puncturing the dome of the aneurysm after satisfactory clipping revealed persistent flow within the aneurysm despite ICG-VA showing no flow after clipping. In one case (0.9%), ICG-VA showed persistent flow within the aneurysm and MUSG did not, and puncture of the dome confirmed no flow within the aneurysm. In one case (0.9%), ICG-VA failed to demonstrate residual neck. CONCLUSION: ICG-VA is a simple and safe procedure and an important adjunct to microsurgical clipping of aneurysm. Although ICG-VA assesses vessel patency and obliteration of aneurysms in most cases, applying the principles of microsurgery in aneurysm clipping remains a main tool for obtaining the complete obliteration of aneurysm along with preservation of the normal vasculature.
Clinical neurology and neurosurgery 09/2012; · 1.30 Impact Factor
[show abstract][hide abstract] ABSTRACT: Of the presigmoid approaches, the translabyrinthine approach is often used when a large exposure is needed to gain access to the cerebellopontine angle but when hearing preservation is not a concern. At the authors' institution, this approach is done with the aid of ENT/otolaryngology for temporal bone drilling and exposure. In the present article and video, the authors demonstrate the use of the translabyrinthine approach for resection of a large cystic vestibular schwannoma, delineating the steps of positioning, opening, temporal bone drilling, tumor resection, and closure. Gross-total resection was achieved in the featured case. The patient's postoperative facial function was House-Brackmann Grade II on the side ipsilateral to the tumor, although function improved with time. The translabyrinthine route to the cerebellopontine angle is an excellent approach for masses that extend toward the midline or anterior to the pons. Although hearing is sacrificed, facial nerve function is generally spared.
[show abstract][hide abstract] ABSTRACT: To report 3 unique cases of cranial neuropathy after super-selective arterial embolization of jugular foramen vascular tumors with ethylene vinyl alcohol.
Clinical capsule report.
Three tertiary academic referral hospitals.
Three patients who underwent superselective arterial embolization (SSE) of head and neck paragangliomas with ethylene vinyl alcohol are described. One individual was treated with primary SSE, whereas the remaining tumors were treated with preoperative SSE followed by surgical extirpation within 72 hours. All patients were found to have new cranial nerve deficits after SSE.
One patient with isolated complete cranial nerve VII palsy demonstrated partial return of function at 8 months. One individual experienced cranial nerve VII, X, and XII palsies and demonstrated partial recovery of function of the involved facial nerve after 19 months. One subject experienced ipsilateral cranial nerve X and XI palsies after SSE and recovered full function of the spinal accessory nerve within 1 week but failed to demonstrate mobility of the ipsilateral true vocal fold.
We present the first report documenting facial and lower cranial neuropathies after super-selective embolization of head and neck paragangliomas with EVA. Although it is difficult to draw conclusions from this small number of cases, it is plausible that the use of ethylene vinyl alcohol during SSE may result in a higher risk of permanent cranial neuropathy than the use of other well-established and more temporary agents. Knowledge of the arterial supply to the cranial nerves can help the clinician to choose the embolization agent that will provide maximal occlusion while minimizing the risk of complications.
Otology & neurotology: official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology 07/2012; 33(7):1270-5. · 1.44 Impact Factor
[show abstract][hide abstract] ABSTRACT: BACKGROUND: Although, the relationship of spontaneous subarachnoid hemorrhage (SAH) to climatic or circadian factors has been widely studied, epidemiologic, circardian and climatic factors in non-aneurysmal SAH (naSAH), particularly perimesencephalic SAH (PMH), has not been reported before. OBJECTIVE: For the first time, demographic, climatic, and circadian variables are examined together as possible contributing factors comparing aSAH and naSAH. METHODS: We reviewed records for 384 patients admitted to University of Wisconsin Neurosurgery Service from January 2005 to December 2010 with spontaneous non-traumatic SAH. Patients were grouped as aSAH (n=338) or naSAH (n=46) on clinical and radiological criteria. PMH (n=32) was identified as a subgroup of naSAH based on radiological criteria. We logged demographic data, time of SAH, temperature at onset and atmospheric pressure at onset. The three subgroups were compared. RESULTS: Aneurysmal SAH occurred most often from 6am to 12pm (p<0.001); this correlation was not found in naSAH or PMH subgroups. Demographic analysis demonstrated predominance of female gender (p=0.008) and smoking (p=0.002) in aSAH, with predominance of hypercholesterolemia in naSAH (p=0.033). Atmospheric pressure, correlated with aSAH in the main county referral area, where we had detailed weather data (p<0.05); however, there was no weather correlation in the entire referral region taken together. Multivariate analysis supported a statistical difference only in smoking status between aSAH and naSAH groups (p=0.0159). CONCLUSION: Statistical differences in gender, smoking status, and history of hypercholesterolemia support a clinical distinction between aSAH and naSAH. Furthermore, circadian patterning of aSAH is not reproduced in naSAH, supporting pathophysiologic differences. Only smoking status provides a robust difference in aSAH and naSAH groups. Our data prompt further investigation into the relationship between aSAH and atmospheric pressure.
Clinical neurology and neurosurgery 07/2012; · 1.30 Impact Factor
[show abstract][hide abstract] ABSTRACT: For successful DREZ (dorsal root entry zone) surgery, optimal neuroanatomical orientation and precise microsurgical dissection are required. Although cervical, lumbar, and sacral spinal segments have been studied in detail, such information is not available for thoracic segments. The objective of this anatomical study is to comprehensively illustrate the microanatomical features of the thoracic DREZs and their variations.
Fifteen formalin-fixed adult cadaveric spinal cords from T1 to T12 were used. The dorsal rootlet numbers, distance between the posteromedial and posterolateral sulcus, length of each DREZ, length of each segment, and mean length of the dorsal rootlets were measured under a surgical microscope.
The longest DREZs were observed at the T6, T7, and T8 segments with mean values of 15.3 mm, 15.6 mm, and 15.4 mm, respectively. The longest segment was observed at the T10 segment with a mean value of 21.0 mm, and the shortest segment was observed at the T1 segment with a mean value of 13.5 mm.
The highest dorsal rootlet density is at the T1 segment of the spinal cord, can be easily distinguished visually, and may be a useful surgical landmark. The DREZs in T6-7 segments are longest, while these two segments have the least number of rootlets. Because the dorsolateral tract is remarkably narrow and the dorsal horn is exceedingly deep, DREZ surgery at the thoracic level may be difficult and risky for the dorsal column and corticospinal tract. Acquaintance with the microanatomy of the DREZ in the thoracic spinal cord is crucial to DREZ surgery.
[show abstract][hide abstract] ABSTRACT: The aim of our study is to suggest the sphenoid wing-lesser wing angulation (SWA) importance during surgeries directed to this region. MATERIAL and
SWA on 40 skulls were measured bilaterally (n=80). The depth of the middle cranial fossa (DMCF) at the level of the SWA was determined. The same measurements were done on 40 randomly selected computerized tomography (CT) scans bilaterally (n=80).
The specimens were classified into 3 groups according the degree of SWA; Group-A, SWA was more than 130° (27%), Group-B, SWA was 110-130° (43%) and Group-C, SWA was less than 110° (28%). MCF was measured (mean) as 10.1 mm in Group-A, 6.4 mm in Group-B and 4.6 mm in Group-C. MCF was increasing with the increase in SWA. CT scans were classified into same procedure. Group-A was 26%, Group-B was 42% and Group-C was 31% fitting in the relevant groups. The superior orbital fissure (SOF) was evaluated according to the Sharma's classification.
We suggest that by the preoperative evaluation of CT scans measurements the SWA, it is possible to estimate the MCF and the type of SOF. This knowledge may be important for all surgeries requiring removal of the sphenoid wing and these region pathologies.
[show abstract][hide abstract] ABSTRACT: Pituitary apoplexy is an infrequent but potentially devastating complication in patients with pituitary adenomas. Previous studies have cited an association between MR visualized sphenoid sinus mucosal thickening and apoplexy. However, uncertainties still remain on the significance and temporal association of this finding with pituitary apoplexy. We provide a clinical study that better delineates this temporal association and also provides histopathologic data for sinus thickening compared to control subjects. MATERIAL and
We report on two patients who received serial MR scans leading to the diagnosis of pituitary apoplexy. Patient 1 demonstrated new sphenoid sinus mucosal thickening with the onset of apoplexy. Patient 2 had progressive thickening of sphenoid sinus mucosa from presentation to repeat scanning demonstrating apoplexy. Both patients underwent transsphenoidal resection of their pituitary adenomas with pathology demonstrating inflamed sphenoid sinus mucosa.
Sphenoid sinus mucosal thickening, as demonstrated on MRI, is temporally associated with pituitary apoplexy, likely as an acute and precedent finding.
[show abstract][hide abstract] ABSTRACT: Bilateral fenestration of the A1 segment of anterior cerebral artery (ACA) is an uncommon anomaly. Our objective is to describe two cases with this anomaly and to review the literature.
A 50-year-old woman presented with subarachnoid hemorrhage from a ruptured A1 aneurysm. Angiography revealed bilateral A1 segment fenestration as well as an aneurysm on the proximal end of fenestration on the right side. The second case is that of an 86-year-old woman who was found to have bilateral fenestration of A1 segment at autopsy.
Bilateral A1 fenestration is an uncommon anomaly that may be associated with an aneurysm. In surgical clipping of such cases, extreme caution should be exercised to inspect both arms of the fenestration since both may have multiple perforators as demonstrated in our autopsy specimen. This will be the first published pictorial demonstration of these perforators arising from the arms of fenestration.
[show abstract][hide abstract] ABSTRACT: Surgical approaches to Meckel's cave (MC) are often technically difficult and sometimes associated with postoperative morbidity. The relationship of surgical landmarks to relevant anatomy is important. Therefore, we attempted to delineate quantitatively their anatomy and the relationships between MC and surrounding structures.
With the aid of a surgical microscope, MC and its contents were studied in 15 formalin-fixed cadaver head specimens. Measurements were made and their relationships were observed.
The distance from the zygomatic arch and the lateral end of the petrous ridge to MC was 26.5 and 34.4 mm, respectively. The distance from the arcuate eminence, the facial nerve hiatus, and the foramen spinosum to MC was 16.6, 12.8 and 7.46 mm respectively. The TG lay 5.81 mm posterior to the foramen ovale. The distance from the abducens, trochlear and oculomotor nerves to the trigeminal ganglion was 1.87, 5.53 and 6.57 mm respectively. The distance from the posterior and the anterior walls of the sigmoid sinus to the trigeminal porus was 43.6 and 33.1 mm respectively. The trigeminal porus was on average 7.19 mm from the anterior wall of the internal acoustic meatus.
The anatomical landmarks as presented herein regarding MC may be used for a safer skull base approach to the region.
[show abstract][hide abstract] ABSTRACT: Fusiform intracranial aneurysms (FIAs) are challenging to treat by surgical and endovascular means because of their complex morphology and configurations. Various surgical techniques, including clip reconstruction, wrapping with or without clip enforcement, and trapping with or without bypass, have been described extensively. The objective of this study is to describe the application of a new fenestrated clip (Yaşargil T-bar clip) for the treatment of FIAs.
An FIA on the M1 segment of the middle cerebral artery was diagnosed incidentally in a 23-year-old man. The aneurysm was visualized after wide dissection of the sylvian fissure. The M1 segment of the middle cerebral artery, its branches, and its lenticulostriate arteries were identified and dissected. A single fenestrated T-bar clip was applied to reconstruct this long FIA after one of the lenticulostriate arteries was dissected free of the aneurysm. Postoperative angiography confirmed reconstruction of the M1 segment and obliteration of the aneurysm.
Clip reconstruction of an FIA with a fenestrated Yaşargil T-bar clip is a new application option that effectively reconstructs the parent artery. Application of this type of a clip might be advantageous over conventional fenestrated or nonfenestrated clip applications, especially in tight surgical fields, because a single clip might be sufficient to reconstruct the long segment of the artery.
[show abstract][hide abstract] ABSTRACT: Although craniofacial approaches to the midline skull base have been defined and surgical results have been published, clear descriptions of these complex approaches in a step-wise manner are lacking. The objective of this study is to demonstrate the surgical technique of craniofacial approaches based on Barrow classification (Levels I-III) and to study the microsurgical anatomy pertinent to these complex craniofacial approaches.
Ten adult cadaveric heads perfused with colored silicone and 24 dry human skulls were used to study the microsurgical anatomy and to demonstrate craniofacial approaches in a step-wise manner. In addition to cadaveric studies, case illustrations of anterior skull base meningiomas were presented to demonstrate the clinical application of the first 3 (Levels I-III) approaches.
Cadaveric head dissection was performed in 10 heads using craniofacial approaches. Ethmoid and sphenoid sinuses, cribriform plate, orbit, planum sphenoidale, clivus, sellar, and parasellar regions were shown at Levels I, II, and III. In 24 human dry skulls (48 sides), a supraorbital notch (85.4%) was observed more frequently than the supraorbital foramen (14.6%). The mean distance between the supraorbital foramen notch to the midline was 21.9 mm on the right side and 21.8 mm on the left. By accepting the middle point of the nasofrontal suture as a landmark, the mean distances to the anterior ethmoidal foramen from the middle point of this suture were 32 mm on the right side and 34 mm on the left. The mean distance between the anterior and posterior ethmoidal foramina was 12.3 mm on both sides; the mean distance between the posterior ethmoidal foramen and distal opening of the optic canal was 7.1 mm on the right side and 7.3 mm on the left.
Barrow classification is a simple and stepwise system to better understand the surgical anatomy and refine the techniques in performing these complex craniofacial approaches. On the other hand, thorough anatomical knowledge of the midline skull base and variations of the neurovascular structures is crucial to perform successful craniofacial approaches.