Faculty Bibliography

BACKGROUND:: Surgical resection of epileptic foci relies on accurate localization of the epileptogenic zone, often achieved by subdural and depth electrodes. Our epilepsy center has treated selected children with poorly localized medically refractory epilepsy with a staged surgical protocol, with at least one phase of invasive monitoring for localization and resection of epileptic foci. OBJECTIVE:: To evaluate the safety of staged surgical treatments for refractory epilepsy among children. METHODS:: Data were retrospectively collected, including surgical details and complications of all patients who underwent invasive monitoring. RESULTS:: 161 children underwent 200 admissions including staged procedures (>1 surgery during one hospital admission), and 496 total surgeries. Average age at surgery was 7y (8m-16.5y). 250 surgeries included resections (and invasive monitoring), and 189 involved electrode placement only. Cumulative total number of surgeries per patient was 2-10 (average 3). Average duration of monitoring was 10 days (1-30). There were no deaths. Follow-up ranged from 1m to 10y. Major complications included unexpected new permanent mild neurological deficits (2%/admission), CNS or bone flap infections (1.5%/admission), intracranial hemorrhage, CSF leak, and a retained strip (each 0.5%/admission). Minor complications included bone absorption (5%/admission), positive surveillance sub/epidural cultures in asymptomatic patients (5.5%/admission), non-infectious fever (5%/admission), and wound complications (3%/admission). 30 complications necessitated additional surgical treatment. CONCLUSION:: Staged epilepsy surgery, with invasive electrode monitoring, is safe in children with poorly localized medically refractory epilepsy. The rate of major complications is low, and appears comparable to that associated with other elective neurosurgical procedures.

Object Subependymal giant cell astrocytomas (SEGAs) are benign tumors, most commonly associated with tuberous sclerosis complex (TSC). The vast majority of these tumors arise from the lateral ependymal surface adjacent to the foramen of Monro, therefore potentially encroaching on one or both foramina, and resulting in obstructive hydrocephalus that necessitates surgical decompression. The indications for surgery, intraoperative considerations, and evolution of the authors' management paradigm are presented. Methods Patients with TSC who underwent craniotomy for SEGA resection at New York University Langone Medical Center between January 1997 and March 2011 were identified. Preoperative imaging, clinical characteristics, management decisions, operative procedures, and outcomes were reviewed. Results Eighteen patients with TSC underwent 22 primary tumor resections for SEGAs. The indication for surgery was meaningful radiographic tumor progression in 16 of 21 cases. The average age at the time of operation was 10.3 years. Average follow-up duration was 52 months (range 12-124 months). The operative approach was intrahemispheric-transcallosal in 16 cases, transcortical-transventricular in 5, and neuroendoscopic in 1. Nine tumors were on the right, 9 on the left, and 3 were bilateral. Gross-total resection was documented in 16 of 22 cases in our series, with radical subtotal resection achieved in 4 cases, and subtotal resection (STR) in 2 cases. Two patients had undergone ventriculoperitoneal shunt placement preoperatively and 7 patients required shunt placement after surgery for moderate to severe ventriculomegaly. Two patients experienced tumor progression requiring reoperation; both of these patients had initially undergone STR. Conclusions The authors present their management strategy for TSC patients with SEGAs. Select patients underwent microsurgical resection of SEGAs with acceptable morbidity. Gross-total resection or radical STR was achieved in 90.9% of our series (20 of 22 primary tumor resections), with no recurrences in this group. Approximately half of our patient series required CSF diversionary procedures. There were no instances of permanent neurological morbidity associated with surgery.

BACKGROUND: Glioblastoma multiforme (GBM) is the most common and lethal primary malignancy of the central nervous system (CNS). Despite the proven benefit of surgical resection and aggressive treatment with chemo- and radiotherapy, the prognosis remains very poor. Recent advances of our understanding of the biology and pathophysiology of GBM have allowed the development of a wide array of novel therapeutic approaches, which have been developed. These novel approaches include molecularly targeted therapies, immunotherapies, and gene therapy. METHODS: We offer a brief review of the current standard of care, and a survey of novel therapeutic approaches for treatment of GBM. RESULTS: Despite promising results in preclinical trials, many of these therapies have demonstrated limited therapeutic efficacy in human clinical trials. Thus, although survival of patients with GBM continues to slowly improve, treatment of GBM remains extremely challenging. CONCLUSION: Continued research and development of targeted therapies, based on a detailed understanding of molecular pathogenesis can reasonably be expected to yield improved outcomes for patients with GBM.

A 7-year-old white girl presented with left hemiparesis and ischemic stroke secondary to moyamoya syndrome, a progressive cerebrovascular occlusive disorder of uncertain but likely multifactorial etiology. Past medical history revealed hearing loss and developmental delay/intellectual disability. Routine karyotype demonstrated extra chromosomal material on 6p. Single nucleotide polymorphism microarray revealed a previously unreported complex de novo genetic rearrangement involving subtelomeric segments on chromosomes 6p and 12q. The duplicated/deleted regions included several known OMIM-annotated genes. This novel phenotype and genotype provides information about a possible association of genomic copy number variation and moyamoya syndrome. Dosage-sensitive genes in the deleted and duplicated segments may be involved in aberrant vascular proliferation. Our case also emphasizes the importance of comprehensive evaluation of both developmental delay and congenital anomalies such as moyamoya.

Intradural intramedullary cervical spinal cord tumors pose a significant challenge for the neurosurgeon to resect with minimal morbidity. We present the case of a 12-year-old male with a cervical ependymoma and demonstrate our resection technique. The video can be found here: http://youtu.be/5DHlnxdggU0 .

Subependymal giant cell astrocytomas (SEGAs) are benign tumors, most commonly associated with tuberous sclerosis complex (TSC). Arising from the lateral ependymal surface, these tumors may obstruct one or both foramina of Monro, resulting in hydrocephalus and often requiring treatment. Although interhemispheric-transcallosal and transcortical-transventricular approaches have been the standard methods for resecting these tumors, advances in neuroendoscopic techniques have expanded SEGAs as a potential target for endoscopic resection. The authors present a case of an endoscopically resected SEGA with stereotactic guidance in a 4-year-old girl with TSC. A gross-total resection of an enlarging SEGA was achieved. This represents one of the early case reports of endoscopically resected SEGAs. Although recent advances in medical treatment for SEGAs with mammalian target of rapamycin (mTOR) pathway inhibitors have shown promising initial results, the long-term safety and efficacy of mTOR inhibitors has yet to be determined. The propensity of these tumors to cause obstructive hydrocephalus requires that a surgical option remain. Neuroendoscopic approaches may allow a safe and effective technique.

Purpose: Intracranial monitoring (IM) is a key diagnostic procedure for select patients with treatment-resistant epilepsy (TRE). Seizure focus resection may improve seizure control in both lesional and nonlesional TRE. IM itself is not considered to have therapeutic potential. We describe a cohort of patients with improved seizure control following IM without resective surgery. Methods: Over 12.5 years, 161 children underwent 496 surgeries including intracranial monitoring. We retrospectively reviewed the patients' charts, operative reports, and radiologic scans, under an institutional review board-approved protocol. Key Findings: Seventeen patients underwent only IM, without additional resective surgery, and seven had a dramatic improvement in their epilepsy; six of the seven patients are seizure-free (Engel class I), and one rarely has seizures (Engel class II). All seven patients had frequent seizures that led to IM: either daily (five patients) or 1-2 per week (two patients). The mean age (+/- standard deviation, SD) at seizure onset was 1.6 +/- 1.3 years (range 0.5-4 years). Etiologies were tuberous sclerosis (3 patients), trauma (1 patient), and unknown (3 patients). Mean age at surgery (+/- SD) was 4.1 +/- 2 years (range 1-7 years), and duration of epilepsy 2.5 +/- 1.1 years (range 0.5-4 years). Duration of IM was 11.7 +/- 5.6 days (5-19 days). Six patients had bilateral and one unilateral invasive electrodes. At last follow-up, four patients required fewer antiepileptic drugs (AEDs), one had the same medication but a higher dose, and two patients were taking additional AEDs. Follow-up was 30.6 +/- 9.5 months (range 19-41 months). Significance: Although uncommon, patients with TRE may improve after IM alone. The explanation for this observation remains unclear; however, perioperative medications including steroids, direct cortical manipulation, or other factors may influence the epileptogenic network

OBJECT: Techniques for the placement of intrathecal baclofen (ITB) systems have been described in detail, with special consideration given to complications from hardware placement. Risks including catheter kinking and migration, hardware erosion through the skin, and lumbar CSF leak are elevated given the often-low body mass index and poor nutritional status of this patient population. The bulk of a spinal catheter and fascial connector within the lumbar wound may increase the potential for the aforementioned risks, leading to potential risks for wound infection and breakdown. The authors' experience has led them to develop a novel method of paraspinal subfascial lumbar catheter placement to address these risks. The authors describe a novel lumbar intrathecal catheter placement technique as part of the ITB system. METHODS: All patients undergoing placement of an ITB system by the senior author at New York University Langone Medical Center between July 2010 and March 2011 underwent paraspinal subfascial lumbar catheter placement. Patients were followed-up by the surgeon 2 weeks after implantation and followed up and managed by their physiatrist thereafter, for an average of 5 months (range 0.5-9 months). Results Of the 20 patients who underwent this method of intrathecal catheter placement, none developed any hardware erosion, catheter migration, or CSF leak. One patient developed an abdominal wound infection 3 weeks after implantation, necessitating pump removal. CONCLUSIONS: In this initial short-term experience, subfascial placement of the lumbar spine intrathecal catheter may be an improvement over the traditional method of catheter placement. There is reduced risk of catheter migration or kinking, hardware erosion, CSF leak, and decreased operative time, all yielding a decreased reoperation rate in this vulnerable population.