Susan R. Durham

Comparison of posterior fossa decompression with and without duraplasty for the surgical treatment of Chiari malformation Type I in pediatric patients: a meta-analysis

OBJECT Surgery for Chiari malformation Type I (CM-I) is one of the most common neurosurgical procedures performed in children, although there is clearly no consensus among practitioners about which surgical method is preferred. The objective of this meta-analysis was to compare the outcome of posterior fossa decompression with duraplasty (PFDD) and posterior fossa decompression without duraplasty (PFD) for the treatment of CM-I in children. METHODS The authors searched Medline-Ovid, The Cochrane Library, and the conference proceedings of the American Association of Neurological Surgeons and the Congress of Neurological Surgeons (2000-2007) for studies meeting the following inclusion criteria: 1) surgical treatment of CM-I; 2) surgical techniques of PFD and PFDD being reported in a single cohort; and 3) patient age < 18 years. RESULTS Five retrospective and 2 prospective cohort studies involving a total of 582 patients met the criteria for inclusion in the meta-analysis. Of the 582 patients, 316 were treated with PFDD and 266 were treated with PFD alone. Patient age ranged from 6 months to 18 years. Patients undergoing PFDD had a significantly lower reoperation rate (2.1 vs 12.6%, risk ratio [RR] 0.23, 95% confidence interval [CI] 0.08-0.69) and a higher rate of cerebrospinal fluid-related complications (18.5 vs 1.8%, RR 7.64, 95% CI 2.53-23.09) than those undergoing PFD. No significant differences in either clinical improvement (78.6 vs 64.6%, RR 1.23, 95% CI 0.95-1.59) or syringomyelia decrease (87.0 vs 56.3%, RR 1.43, 95% CI 0.91-2.25) were noted between PFDD and PFD. CONCLUSIONS Posterior fossa decompression with duraplasty is associated with a lower risk of reoperation than PFD but a greater risk for cerebrospinal fluid-related complications. There was no significant difference between the 2 operative techniques with respect to clinical improvement or decrease in syringomyelia.

Age-Related Differences in Acute Physiologic Response to Focal Traumatic Brain Injury in Piglets

Introduction: The goal of the present study was to determine whether age-related differences in the acute physiologic response to scaled cortical impact injury contribute to differences in vulnerability to traumatic brain injury (TBI). Methods: Heart rate (HR), mean arterial pressure (MAP), brain temperature (BrT) and cerebral blood flow (CBF) were measured in 22 piglets (7 of age 5 days, 8 of age 1 month, 7 of age 4 months) at baseline and for 3 h following scaled cortical impact injury. Results: There were no age-dependent variations from baseline in HR, MAP or BrT following injury. CBF increased in the 5-day-old animals following injury while CBF in the 1- and 4-month-old animals decreased following injury (p = 0.0049). Conclusion: CBF was shown to have a significant age-dependent response to TBI with the youngest animals exhibiting increased CBF following injury.

A 15-year review of pediatric neurosurgical fellowships: implications for the pediatric neurosurgical workforce

OBJECT The Accreditation Council for Pediatric Neurosurgical Fellowships (ACPNF) was established in 1992 to oversee fellowship training in pediatric neurological surgery. The present study is a review of all graduates from 1992 through 2006 to identify predictors of American Board of Pediatric Neurological Surgery (ABPNS) certification. METHODS Basic demographic information including sex, year of graduation from residency, residency training program, year of fellowship training, and fellowship program was collected on each graduate from each of the 22 ACPNF programs. Individuals who did not meet ACPNF requirements (39 trainees) and those currently practicing in Canada (11 individuals) were excluded. Univariate and multivariate analysis were used to identify predictors of ABPNS certification. RESULTS Of the 193 ACPNF graduates, 143 individuals met the criteria for analysis. Currently, 70 (49%) are ABPNS certified. There is a mean period of 5.1 +/- 2.4 years (range 2-13 years) between finishing fellowship and ABPNS certification. If those who are not expected to be sitting for the boards yet (2002-2006 graduates, 57 individuals) are removed, the rate of ABPNS certification is 66.3%. On average, 9.5 +/-3.0 (range 4-16) fellows are trained per year. There is no statistically significant relationship between fellowship or residency training program and ABPNS certification. CONCLUSIONS Although the present training infrastructure has the theoretical capacity to train > 20 pediatric neurosurgeons each year, this analysis suggests that current levels will provide approximately 6 ABPNS-certified pediatric neurosurgeons annually. This raises the question of the sufficiency of the future pediatric neurosurgical workforce.

A prospective natural history study of nonoperatively managed Chiari I malformation: does follow-up MRI surveillance alter surgical decision making?

OBJECT Chiari malformation Type I (CM-I) in children is a common incidental finding. Resolution of cerebellar tonsil ectopia has been reported, but no studies have followed tonsil position over regular intervals throughout childhood. To better elucidate the clinical and radiological natural history of CM-I in children, the authors prospectively followed up children with nonoperatively managed CM-I for up to 7 years. METHODS The study included all children evaluated for CM-I over a period of 12 years for whom surgery was not initially recommended. The study excluded patients with associated conditions, including syringomyelia and hydrocephalus. For all patients, initial management was nonoperative, and follow-up management consisted of annual cervical spine or brain MRI and clinical examination. At each follow-up examination, the neurological examination findings, subjective symptoms, and the position of the cerebellar tonsils on MR images were recorded. An alteration in tonsillar descent of 2 mm or greater was considered a change. RESULTS Neurological examination findings did not change over the course of the study in the 52 children who met the inclusion criteria. Although radiological changes were common, no surgeries were performed solely because of radiological change. Overall, tonsil position on radiological images remained stable in 50% of patients, was reduced in 38%, and increased in 12%. Resolution was seen in 12% of patients. Radiological changes in tonsil position were seen during every year of follow-up. On average, in any given year, 24% of images showed some form of change in tonsil position. A total of 3 patients, for whom no changes were seen on MR images, ultimately underwent surgery for subjective clinical reasons. CONCLUSIONS CM-I in children is not a radiologically static entity but rather is a dynamic one. Radiological changes were seen throughout the 7 years of follow-up. A reduction in tonsillar descent was substantially more common than an increase. Radiological changes did not correlate with neurological examination finding changes, symptom development, or the need for future surgery. Follow-up imaging of asymptomatic children with CM-I did not alter treatment for any patient. It would be reasonable to follow these children with clinical examinations but without regular surveillance MRI.

Analysis of the 1990–2007 neurosurgery residency match: does applicant gender affect neurosurgery match outcome?

OBJECTIVE With nearly half of graduating US medical students being female, it is imperative to understand why females typically make up less than 20% of the neurosurgery applicant pool, a number that has changed very slowly over the past several decades. Organized neurosurgery has strongly indicated the desire to overcome the underrepresentation of women, and it is critical to explore whether females are at a disadvantage during the residency application process, one of the first steps in a neurosurgical career. To date, there are no published studies on specific applicant characteristics, including gender, that are associated with match outcome among neurosurgery resident applicants. The purpose of this study is to determine which characteristics of neurosurgery residency applicants, including gender, are associated with a successful match outcome. METHODS De-identified neurosurgical resident applicant data obtained from the San Francisco Fellowship and Residency Matching Service for the years 1990-2007 were analyzed. Applicant characteristics including gender, medical school attended, year of application, United States Medical Licensing Exam (USMLE) Step 1 score, Alpha Omega Alpha (AOA) status, and match outcome were available for study. RESULTS Of the total 3426 applicants studied, 473 (13.8%) applicants were female and 2953 (86.2%) were male. Two thousand four hundred forty-eight (71.5%) applicants successfully matched. USMLE Step 1 score was the strongest predictor of match outcome with scores > 245 having an OR of 20.84 (95% CI 10.31-42.12) compared with those scoring < 215. The mean USMLE Step 1 score for applicants who successfully matched was 233.2 and was 210.8 for those applicants who did not match (p < 0.001). Medical school rank was also associated with match outcome (p < 0.001). AOA status was not significantly associated with match outcome. Female gender was associated with significantly lower odds of matching in both simple (OR 0.59, 95% CI 0.48-0.72) and multivariate analyses (OR 0.57, 95% CI 0.34-0.94 CI). USMLE Step 1 scores were significantly lower for females compared to males with a mean score of 230.1 for males and 221.5 for females (p < 0.001). There was no significant difference in medical school ranking or AOA status when stratified by applicant gender. CONCLUSIONS The limited historical applicant data from 1990-2007 suggests that USMLE Step 1 score is the best predictor of match outcome, although applicant gender may also play a role.