Aaron Cohen-Gadol

Resident duty hours reform: results of a national survey of the program directors and residents in neurosurgery training programs.

OBJECTIVE:The new Accreditation Council for Graduate Medical Education (ACGME) requirements regarding resident work hours have been implemented since July 2003. Neurological surgery training programs have been especially affected because of the limited number of residency positions and the residents’ long duty hours. The perceptions of program directors and residents may provide important insight into the evolution of new guidelines for improvement of resident training. METHODS:We conducted a nationwide survey of 93 program directors and 617 residents to characterize their perceptions regarding the changes in their training programs related to compliance with the ACGME requirements. The survey was conducted from July through September 2003 using electronic mail. RESULTS:The response rates were 45% and 23% among the program directors and residents, respectively. Most programs offered one (37%) or two (38%) resident training positions per year. Although 92% of programs had implemented the ACGME work hours requirements before or since July 2003, 8% had not yet implemented these guidelines. Sixty-eight percent of program directors indicated employment of ancillary health care professionals to fulfill the ACGME duty hours reform; 84% (95% confidence interval [CI], 64–94%) thought that this practice has not limited the residents’ clinical experience. Eleven percent of respondents (18 of 164 respondents) who provided Level I trauma coverage were unable to maintain compliance with the ACGME guidelines. Ninety-three percent (95% CI, 89–96%) of all respondents thought that the work hour reform has had a negative impact on the continuity of patient care. Fifty-five percent (95% CI, 46–63%) of the residents and only 33% (95% CI, 20–50%) of the program directors thought that the ACGME requirements are likely to result in improved American Board of Neurological Surgery written test scores. Twenty-nine percent (95% CI, 22–37%) of the residents and 17% (95% CI, 8–32%) of the program directors thought that resident attendance at national conferences would increase. Similarly, although 46% (95% CI, 37–54%) of residents perceived that these work hour limitations would facilitate residents’ research/publication-related activities, only 21% (95% CI, 11–37%) of program directors agreed. Forty-one percent (95% CI, 33–49%) of the residents and 74% (95% CI, 58–86%) of the program directors perceived that the chief residents operate on fewer complex cases since the institution of the ACGME duty hour guidelines. Seventy-five percent of residents think they are less familiar with their patients. Overall, 61% (95% CI, 53–69%) of the residents and 79% (95% CI, 63–89%) of the program directors noted that the ACGME guidelines have had a negative effect on their training programs. CONCLUSION:On the basis of their early experience, the majority of the residents and program directors think that the ACGME duty hour guidelines have had an adverse effect on continuity of patient care and resident training. The effects of these guidelines on neurosurgery programs should be carefully monitored, because more sophisticated solutions may be needed to address house staff fatigue. Strategies to enhance the educational content of the residents’ work hours and to preserve continuity of patient care are necessary.

Surgical Anatomy of Dural Defects in Spontaneous Spinal Cerebrospinal Fluid Leaks

OBJECTIVE: Spontaneous intracranial hypotension is typically caused by a spontaneous spinal cerebrospinal fluid (CSF) leak. The configuration of the related dural defects can be complex. We describe our experience with the surgical anatomy of these defects. METHODS: Thirteen consecutive patients with spontaneous spinal CSF leaks who underwent surgical exploration at Mayo Clinic between 1994 and 2003 were studied. All patients’ records, imaging studies, detailed intraoperative findings, and outcomes were reviewed. RESULTS: There were four men and nine women with an average age of 40 years (range, 12–62 yr). Preoperative imaging studies revealed a single site of CSF leak in eight patients, two sites in three patients, and multiple sites in two patients. Intraoperatively, the exact site of leakage could not be found in four patients. Among the other nine patients, primary closure of a meningeal diverticulum was achieved in one patient. Significant regional attenuation of the dura prevented primary repair of the leak site in eight patients. Muscle, fibrin glue, and Gelfoam (Upjohn Co., Kalamazoo, MI) soaked in patient’s own blood were commonly used to pack the epidural space in an attempt to seal the site of the leak. Ligation of two nonappendicular nerve roots allowed closure of the leak in one of these patients. Postoperatively, resolution of symptoms occurred in eight patients, significant improvement was noted in three patients, and only transient resolution in two. The mean duration of follow-up was 20.5 months. CONCLUSION: Surgery for closure of spontaneous spinal CSF leaks may not be straightforward. Even when extradural CSF leakage is discovered preoperatively by imaging studies, it may not always be possible to identify the exact site of the leakage intraoperatively. Furthermore, the anatomy of the dural defects may be complex and not amenable to primary closure. In such cases, the use of adjuvant techniques during surgical exploration may be effective.

Spinal cord biopsy: a review of 38 cases.

OBJECTIVENeurosurgeons are frequently asked to evaluate patients for spinal cord biopsies when preoperative magnetic resonance imaging studies demonstrate nonspecific features. These lesions often appear unresectable, but surgeons must decide whether a biopsy is warranted. To determine the best approach to these cases, we evaluated the clinicopathological findings for patients with unknown spinal cord lesions who underwent spinal cord biopsies. METHODSThirty-eight consecutive patients who underwent spinal cord biopsies at the Mayo Clinic (Rochester, MN) between August 1988 and July 1998 were studied. A detailed review of the case histories, radiological results, surgical notes, histological findings, and outcomes was performed. RESULTSSpinal cord biopsies were performed for 21 male and 17 female patients (mean age, 42.1 yr) with progressive neurological deficits related to spinal cord lesions. All patients underwent preoperative magnetic resonance imaging evaluations. High T2-weighted signal intensity and spinal cord expansion were identified in 92 and 87% of cases, respectively. After gadolinium infusion, the majority (94%) of the inflammatory lesions demonstrated patchy and often peripherally situated enhancement. This neuroradiological pattern was less common for neoplasms (50%) and benign lesions (40%). The most common pathological findings were inflammatory changes of demyelination or sarcoidosis, which together accounted for 13 cases (34%). Nonspecific changes or benign lesions were observed in 10 cases (26%). Neoplasms were identified in eight cases (21%). One case of tuberculosis and one of schistosomiasis were found. Overall, 47% of the preoperative diagnoses made by the attending surgeon were correct. For 26% of the patients, specific treatment was based on the biopsy results. The average follow-up period was 12 months (standard deviation, 14 mo; range, 0–50 mo). CONCLUSIONPreoperative laboratory and imaging studies are often diagnostically inconclusive in cases of spinal cord lesions with nonspecific features. Biopsies should be considered for patients with progressive symptomatic lesions.

Neurostimulation Therapy for Epilepsy: Current Modalities and Future Directions

Neurostimulation is a recent development in the treatment of epilepsy. Vagus nerve stimulation (VNS), the only approved neurostimulation therapy for epilepsy to date, has proved to be a viable adjunctive treatment option. The exact mechanism of action of VNS is not fully understood. In 2 randomized double-blind trials, seizure frequency declined approximately 30% after 3 months of treatment. Long-term follow-up studies suggest that response improves over time, with approximately 35% of patients experiencing a 50% reduction and 20% experiencing a 75% reduction in seizure frequency after 18 months of treatment. Unfortunately, the number of patients rendered medication-free and seizure-free with VNS is low. Vagus nerve stimulation is best viewed as an option for patients who are not surgical candidates or who hesitate to take the risk of surgery yet continue to have seizures despite maximal medical therapy. Stimulation of other regions of the central nervous system for treating epilepsy, including the anterior and centromedian nuclei of the thalamus, the hippocampus, the subthalamic nucleus, and the cerebral neocortex, is currently under investigation. We review the history, proposed mechanisms of action, clinical trials, adverse effects, and future direction of VNS and other modalities of neurostimulation therapy for epilepsy.

Transient cortical abnormalities on magnetic resonance imaging after status epilepticus: Case report

INTRODUCTION Transient neuroimaging findings associated with seizure activity have received relatively little attention in the neurosurgical literature. These abnormalities may mimick neoplastic or ischemic changes on magnetic resonance imaging (MRI), possibly leading to additional studies and surgical treatment. CASE DESCRIPTION A 17-year-old right-handed male was transferred to emergency room in status epilepticus. A MRI obtained 5 months before admission was negative. On the day of admission, he had multiple intermittent upper-left extremity partial seizures and prolonged secondary generalized seizures. An electroencephalogram (EEG) showed frequent epileptiform discharges over the right hemisphere posteriorly. A MRI study performed 2 days after admission revealed non-hemorrhagic abnormalities involving the right occipital region that were hyperintense on fluid-attenuated inversion recovery (FLAIR) and T2 weighted sequences. The apparent diffusion coefficient map was unremarkable. Follow-up MRIs, 3 and 11 months after admission, showed complete resolution of these lesions. CONCLUSION Imaging findings after status epilepticus may raise suspicion of ischemic or neoplastic lesions. These findings may be reversible. Further follow-up imaging may prevent unnecessary intervention.

Frontal lobe epilepsy: diagnosis and surgical treatment

Frontal lobe epilepsy has been better understood during the past two decades with the advent of technologies with improved localizing capabilities. Major technological advances in the ability to delineate structural and functional brain regions have led to a resurgence of interest in epilepsy surgery. Neuroimaging modalities have broadened the scope of what are now considered surgically remediable syndromes. In the following article, we attempt to review the current concepts regarding diagnosis and surgical management of frontal lobe epilepsy.

Non-enhancing de novo glioblastoma: report of two cases.

Malignant gliomas arise from two distinct pathways, as de novo lesions or from secondary transformation from low-grade lesions. Herein, we describe the cases of two patients to illustrate the proposition that de novo malignant gliomas can originate as non-enhancing tumors and rapidly progress to a pattern of ring enhancement characteristic of a glioblastoma. Both patients presented with new-onset seizures (simple partial and generalized). Their neurological examinations were unremarkable. Initial MRI evaluations revealed a right precentral gyrus and right medial temporal lobe lesions in each case, respectively. These lesions demonstrated increased T2 signal changes without contrast enhancement. The biopsy of the right frontal lesion in the first patient was consistent with an anaplastic astrocytoma; the second patient was followed expectantly. Repeat MRI for both patients within 17 weeks disclosed ring-enhancing lesions, consistent with an unusually rapid evolution to glioblastoma multiforme (GBM). Subsequent resection of the right medial temporal lesion in the second patient revealed a GBM. Neither tumor displayed abnormal overexpression of P53 by immunohistochemistry. Early MRI of de novo glioblastomas may demonstrate a non-enhancing tumor suggestive of a low-grade lesion. These tumors can rapidly evolve into ring-enhancing lesions more consistent with the traditional imaging findings.

Circumferential decompression of the foramen magnum for the treatment of syringomyelia associated with basilar invagination.

Posterior fossa decompression utilizing suboccipital craniectomy and duraplasty remains the standard surgical treatment for Chiari-associated syringomyelia. In the presence of basilar invagination, anterior decompression, typically transoral odontoidectomy, or posterior decompression may be performed. We report two cases in which anterior and posterior (circumferential) decompression of the foramen magnum was used to treat cervical syringomyelia successfully. These cases demonstrate that circumferential decompression of the foramen magnum may be necessary in some cases of cervical syringomyelia associated with basilar invagination and Chiari malformation.

Cortical Resection for Epilepsy in Children with Linear Sebaceous Nevus Syndrome

Linear sebaceous nevus syndrome (LSNS) is a rare neurocutaneous syndrome that is associated with seizures and mental retardation. The cortical abnormalities that are associated with this syndrome include focal cortical dysplasia, partial hemimegalencephaly and holohemispheric hemimegalencephaly. Few reports have addressed the utility of cortical resections for epilepsy treatment in the setting of LSNS. We report 3 children with this syndrome who underwent extensive cortical resections and experienced significant improvement in seizure frequency. Our results support the utility of extensive cortical resections for children with this condition.

Intramedullary spinal cord gangliocytoma: case report and a review of the literature.

We present a case of intramedullary spinal gangliocytoma in a 19-year-old woman who presented with a long history of hyperhidrosis of the face and neck areas and intermittent pain of the hands. The tumor involved the cervico-thoracic region of the spinal cord from C7-T3. The patient underwent debulking of the lesion and remains neurologically stable at two years follow-up. A discussion of this case is followed by a review of the literature surrounding this rare clinicopathological entity.