Sepehr Sani

Treatment of a middle cerebral artery bifurcation aneurysm using a double neuroform stent "Y" configuration and coil embolization: technical case report.

OBJECTIVE AND IMPORTANCE: Wide-necked cerebral aneurysms have been particularly difficult to treat using coil embolization. The introduction of the first intracranial flexible stent (Neuroform stent; Boston Scientific/Target, Fremont, CA) has provided a great advantage to this dilemma by forming a bridge across the aneurysm neck and allowing the packing of coils. Despite this advancement, some parent vessel bifurcation aneurysms can still remain elusive to single stent and coiling technique. CLINICAL PRESENTATION: A 55-year-old woman presented for a routine follow-up angiogram. Her past history was significant for a subarachnoid hemorrhage and clipping of an anterior communicating aneurysm with full recovery. An incidental new right middle cerebral artery aneurysm was found on the angiogram. We report here a case of an unruptured asymptomatic wide-neck middle cerebral artery bifurcation aneurysm that was treated with a novel endovascular repair. INTERVENTION: The aneurysm was successfully treated using a double stent “Y” configuration and coil embolization technique using the Neuroform stent. Technical aspects are discussed. Perioperative management issues and potential pitfalls are also considered. CONCLUSION: Double stenting in “Y” configuration and coiling is feasible. This technique should increase the ability to endovascularly treat wide-necked aneurysms.

Factors involved in long-term efficacy of deep brain stimulation of the thalamus for essential tremor

OBJECT Although nucleus ventralis intermedius stimulation has been shown to be safe and efficacious in the treatment of essential tremor, there is a subset of patients who eventually lose benefit from their stimulation. Proposed causes for this phenomenon include tolerance, disease progression, and suboptimal location. The goal of this study was to assess the factors that may lead to both stimulation failure, defined as loss of meaningful tremor relief, and less satisfactory outcomes, defined as leads requiring voltages>3.6 V for effective tremor control. METHODS The authors present their clinical outcomes from 31 leads in 27 patients who had effective tremor control for >1 year following nucleus ventralis intermedius stimulation. All patients postoperatively had a mean decrease in both the writing and drawing subscales of the Fahn-Tolosa-Marin Tremor Rating Scale (p<0.001). RESULTS After a mean follow-up of 40 months, 22 patients continued to have tremor control with stimulation. Four patients eventually lost efficacy of their stimulation at a mean of 39 months. There was no difference in age, duration of disease, or disease severity between the groups. Examination of perioperative factors revealed that suboptimal anteroposterior positioning as evidenced on intraoperative fluoroscopy occurred significantly more frequently in patients with stimulation failure (p=0.018). In patients with less satisfactory outcomes, no difference was seen between group demographics. Fluoroscopy again revealed suboptimal positioning more frequently in these patients (p=0.005). CONCLUSIONS This study provides further evidence that suboptimal lead position in combination with disease progression or tolerance may result in less satisfactory long-term outcomes.

Deep Brain Stimulation for Medically Intractable Cluster Headache

Cluster headache is the most severe primary headache disorder known. Ten to 20% of cases are medically intractable. DBS of the posterior hypothalamic area has shown effectiveness for alleviation of cluster headache in many but not all of the 46 reported cases from European centers and the eight cases studied at the University of California, San Francisco. This surgical strategy was based on the finding of increased blood flow in the posterior hypothalamic area on H(2)(15)O PET scanning during spontaneous and nitroglycerin-induced cluster headache attacks. The target point used, 4-5 mm posterior to the mamillothalamic tract, is in the border zone between posterior hypothalamus, anterior periventricular gray matter, and inferior thalamus. Recently, occipital nerve stimulation has shown efficacy, calling in question the use of DBS as a first line surgical therapy. In this report, we review the indications, techniques, and outcomes of DBS for cluster headache.

Medically intractable temporal lobe epilepsy in patients with normal MRI: surgical outcome in twenty-one consecutive patients.

INTRODUCTION Abnormal MRI findings localizing to the mesial temporal lobe predict a favorable outcome in temporal lobe epilepsy surgery. The purpose of this study is to summarize the surgical outcome of patients who underwent a tailored antero-temporal lobectomy (ATL) with normal 1.5 T MRI. Specifically, factors that may be associated with favorable post-surgical seizure outcome are evaluated. METHODS A retrospective analysis of the Rush University Medical Center surgical epilepsy database between 1992 and 2003 was performed. Patients who underwent an ATL and had a normal MRI study documented with normal volumetric measurements of hippocampal formations and the absence of any other MRI abnormality were selected for this study. Demographic information was collected on all patients. Seizure outcomes were evaluated using Engels classification. A two-sided Fisher exact test with Bonferroni correction was performed in statistical analyses. RESULTS Twenty-one (21) patients met the inclusion criteria of normal 1.5 T MRI and underwent a tailored temporal lobectomy. Mean age at time of surgery was 28 years (SD=8.1, range 11-44) and mean duration of the seizure disorder was 13.4 years (range 2-36). Risk factors for epilepsy included head injury (n=4), encephalitis (n=3), febrile seizures (n=2), and 12 patients had no risk factors. Pathological evaluation of resected tissue revealed no abnormal pathology in 12/21 patients (57%). After a mean 4.8 years follow-up post-surgical period, 15/21 (71%) patients were free of disabling seizures (Engel I outcome). At 8.3 years follow-up, 13/21 (62%) patients had similar results. Absence of prior epilepsy risk factors was the only statistically significant predictor of an Engel class I outcome (p<0.0022). CONCLUSION Patients with medically intractable epilepsy and normal MRI appear to benefit from epilepsy surgery. Absence of prior epilepsy risk factors may be a positive prognostic factor.

A Critical Review of Cervical Laminoplasty

PurposeLaminoplasty was developed in the 1970s as an alternative technique to laminectomy in treating patients with ossified posterior longitudinal ligaments or cervical spondylosis. The proposed advantage was expansion of the spinal canal while preserving spinal stability and preventing the formation of postlaminectomy kyphosis. MethodsA meta-analysis of the laminoplasty literature was performed. Outcome measures included postoperative cervical alignment, change in range of motion (ROM), neurologic outcome, and complications. ResultsSeventy-one studies comprising more than 2000 patients were reviewed. All studies were retrospective and nonrandomized. There was worsening of cervical alignment after laminoplasty in 35% of patients. Ten percent of long-term follow-up patients developed postlaminoplasty kyphosis. There was significant progressive decrease in cervical ROM after laminoplasty, with a mean decrease of 50%. In long-term follow-up studies, the ROMs of laminoplasty patients paralleled those of laminectomy patients. The mean recovery rate was 55% (range: 20%–80%), with approximately 80% of patients improving. There was no difference in neurologic outcome based on laminoplasty versus laminectomy or on the different types of laminoplasty techniques used. Reporting of complications was inconsistent. There was no evidence of postlaminectomy membrane leading to neurologic compromise or deterioration. Postoperative C5 nerve root dysfunction was reported by a few studies, and the incidence was approximately 8%. Axial neck pain after laminoplasty was noted in 6% to 60% of patients. ConclusionsThere is no benefit of laminoplasty over laminectomy and fusion in terms of preservation of spinal alignment, kyphotic deformity, and neurologic outcome, which we identify after this review.

Postoperative acute disseminated encephalomyelitis after exposure to microfibrillar collagen hemostat

Microfibrillar collagen hemostat, known by its trade name Avitene, has been used in neurosurgery for decades. Complications with this product have been documented in other surgical specialties and described as mostly immune-mediated foreign-body reactions that can lead to a granulomatous reaction. There has never been a case of disseminated encephalomyelitis associated with this topical hemostatic agent. In this report the authors present a case of postoperative acute disseminated encephalomyelitis after exposure to Avitene. Possible pathophysiological mechanisms are discussed and the pertinent literature is reviewed.

Acute global ischemic stroke after cranioplasty: case report and review of the literature.

Introduction:Cranioplasty procedures are performed usually after devastating neurological injuries requiring craniectomies. Although relatively safe, global intracerebral infarction is a poorly understood, and most often, lethal complication after cranioplasty. We report here one such case with a thorough literature review with insight as to possible etiologies of this injury. Case Report:A 14-year-old girl underwent a left-sided decompressive hemicraniectomy for treatment of a subdural hematoma and cerebral edema. The patient’s neurological condition eventually improved and she presented for cranioplasty repair of the defect 83 days after her initial operation. Six hours after an uneventful procedure, the patient’s neurological examination declined. Immediate CT scan revealed global edema. Despite all treatment measures, the patient progressed to global ischemia and brain death and expired. Conclusions:Although global intracerebral infarction after cranioplasty is extremely rare, the concepts of vessel injury, venous stasis, and reperfusion into dysfunctional cerebral tissue after cranioplasty should be considered when evaluating the risk of this procedure.

Microelectrode recording in the posterior hypothalamic region in humans.

INTRODUCTION Deep brain stimulation of the posterior hypothalamic region (PHR) is an emerging technique for the treatment of medically intractable cluster headache. Few reports have analyzed single unit neuronal recordings in the human PHR. We report properties of spontaneous neuronal discharge in PHR for 6 patients who underwent DBS for cluster headaches. METHODS Initial target coordinates, determined by magnetic resonance imaging stereotactic localization, were 2 mm lateral, 3 mm posterior, and 5 mm inferior to the midpoint of the anterior commissure-posterior commissure plane. A single microelectrode penetration was performed beginning 10 mm above the anatomic target, without systemic sedation. Single units were discriminated off-line by cluster cutting in principal components space. Discharge rates, interspike intervals, and oscillatory activity were analyzed and compared between ventromedial thalamic and hypothalamic units. RESULTS Six patients and 24 units were evaluated. Units in the PHR had a slow, regular spontaneous discharge with wide, low-amplitude action potentials. The mean discharge rate of hypothalamic neurons was significantly lower (mean ± standard deviation, 13.2 ± 12.2) than that of medial thalamic units (28.0 ± 8.2). Oscillatory activity was not detected. Microelectrode recording in this region caused no morbidity. CONCLUSION The single-unit discharge rate of neurons in the PHR of awake humans was 13.2 Hz and was significantly lower than medial thalamic neurons recorded dorsal to the target. The findings will be of use for microelectrode localization of the cluster headache target and for comparison with animal studies.

Microsurgical anatomy of the transsylvian translimen insula approach to the mediobasal temporal lobe: Technical considerations and case illustration.

Background: Various vascular, neoplastic, and epileptogenic pathologies occur in the mediobasal temporal region. A transsylvian translimen insula (TTI) approach can be used as an alternative to temporal transcortical approach to the mediobasal temporal region. The aim of this study was to demonstrate the surgical anatomy of the TTI approach, including the gyral, sulcal, and vascular anatomy in and around the limen insula. The use of this approach is illustrated in the resection of a complex arteriovenous malformation. Methods: The TTI approach to the mediobasal temporal region was performed on three silicone-injected cadaveric heads. The gyral, sulcal, and arterial anatomy of the limen insula was studied in six formalin-fixed injected hemispheres. Results: The TTI approach provided access to the anterior and middle segments of the mediobasal temporal lobe region as well as allowing access to temporal horn of the lateral ventricle. Using this approach we were able to successfully resect an arteriovenous malformation of the dominant medial temporal lobe. Conclusion: The TTI approach provides a viable surgical route to the region of mediobasal temporal lobe region. This approach offers an advantage over the temporal transcortical route in that there is less risk of damage to optic radiations and speech area in the dominant hemisphere.

Cervical stenosis presenting with acute Brown-Séquard syndrome: case report.

Study Design. An unusual case report of cervical stenosis presenting with the Brown-Séquard syndrome. Technical considerations and a literature review are discussed. Objective. To evaluate cervical stenosis as an etiology of the Brown-Séquard syndrome and whether surgical decompression is effective for improving neurologic outcome. Summary of Background Data. Of the causes of the Brown-Séquard syndrome, intrinsic cervical spine pathology has rarely been reported in the literature. We report the first case of a chronic cervical stenosis presenting with an acute Brown-Séquard syndrome after a severe coughing episode. Methods. A 75-year-old woman with a previous history of cervical stenosis had sudden onset of weakness develop in the right upper and lower extremities, and disruption of pain and temperature sensation on the left side of her body after an episode of severe coughing associated with pneumonia. Magnetic resonance imaging of the cervical spine revealed severe canal stenosis from C3 through C7, with diffuse intramedullary hyperintensity consistent with myelomalacia of the cervical cord. A decompressive cervical laminectomy with fusion was performed. Results. The patient improved neurologically, with near complete resolution of the right hemiparesis at 6-month follow-up. Conclusion. Multilevel chronic cervical stenosis can present with an acute Brown-Séquard syndrome. Cervical laminectomy and decompression are effective treatments for cervical stenosis with an acute Brown-Séquard syndrome.