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Rosemary T. Behmer Hansen, Nicole A. Silva, Rebecca Cuevas, Samantha Y. Cerasiello, Angela M. Richardson, Antonios Mammis and Anil Nanda

OBJECTIVE

Current data on fellowship choice and completion by neurosurgical residents are limited, especially in relation to gender, scholarly productivity, and career progression. The objective of this study was to determine gender differences in the selection of fellowship training and subsequent scholarly productivity and career progression.

METHODS

The authors conducted a quantitative analysis of the fellowship training information of practicing US academic neurosurgeons. Information was extracted from publicly available websites, the Scopus database, and the Centers for Medicare and Medicaid Services Open Payments website.

RESULTS

Of 1641 total academic neurosurgeons, 1403 (85.5%) were fellowship trained. There were disproportionately more men (89.9%) compared to women (10.1%). A higher proportion of women completed fellowships than men (p = 0.004). Proportionally, significantly more women completed fellowships in pediatrics (p < 0.0001), neurooncology (p = 0.012), and critical care/trauma (p = 0.001), while significantly more men completed a spine fellowship (p = 0.012). Within those who were fellowship trained, the academic rank of professor was significantly more commonly held by men (p = 0.001), but assistant professor was held significantly more often by women (p = 0.017). The fellowships with the largest mean h-indices were functional/stereotactic, pediatrics, and critical care/trauma. Despite more women completing neurooncology and pediatric fellowships, men had significantly greater h-indices in these subspecialties compared to women. Women had more industry funding awards than men in pediatrics (p < 0.0001), while men had more in spine (p = 0.023).

CONCLUSIONS

Women were found to have higher rates for fellowship completion compared with their male counterparts, yet had lower scholarly productivity in every subspecialty. Fellowship choice remains unequally distributed between genders, and scholarly productivity and career progression varies between fellowship choice.

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Michael S. Rallo, Omar Ashraf, Fareed Jumah, Gaurav Gupta and Anil Nanda

OBJECTIVE

Engagement in research and scholarship is considered a hallmark of neurosurgical training. However, the participation of neurosurgical trainees in this experience has only recently been analyzed and described in the United States, with little, if any, data available regarding the research environment in neurosurgical training programs across the globe. Here, the authors set out to identify requirements for research involvement and to quantify publication rates in leading neurosurgical journals throughout various nations across the globe.

METHODS

The first aim was to identify the research requirements set by relevant program-accrediting and/or board-certifying agencies via query of the literature and published guidelines. For the second part of the study, the authors attempted to determine each country’s neurosurgical research productivity by quantifying publications in the various large international neurosurgical journals—World Neurosurgery, Journal of Neurosurgery, and Neurosurgery—via a structured search of PubMed.

RESULTS

Data on neurosurgical training requirements addressing research were available for 54 (28.1%) of 192 countries. Specific research requirements were identified for 39 countries, partial requirements for 8, and no requirements for 7. Surprisingly, the authors observed a trend of increased average research productivity with the absence of designated research requirements, although this finding is not unprecedented in the literature.

CONCLUSIONS

A variety of countries of various sizes and neurosurgical workforce densities across the globe have instituted research requirements during training and/or prior to board certification in neurosurgery. These requirements range in intensity from 1 publication or presentation to the completion of a thesis or dissertation and occur at various time points throughout training. While these requirements do not correlate directly to national research productivity, they may provide a foundation for developing countries to establish a culture of excellence in research.

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Travis Quinoa, Fareed Jumah, Vinayak Narayan, Zhenggang Xiong, Anil Nanda and Simon Hanft

Central nervous system infections in immunosuppressed patients are rare but potentially lethal complications that require swift diagnoses and intervention. While the differential diagnosis for new lesions on neuroradiological imaging of immunosuppressed patients typically includes infections and neoplasms, image-based heuristics to differentiate the two has been shown to have variable reliability.

The authors describe 2 rare CNS infections in immunocompromised patients with atypical physical and radiological presentations. In the first case, a 59-year-old man, who had recently undergone a renal transplantation, was found to have multifocal Nocardia amikacinitolerans abscesses masquerading as neoplasms on diffusion-weighted imaging (DWI); in the second case, a 33-year-old man with suspected recurrent Hodgkin’s lymphoma was found to have a nonpyogenic abscess with cytomegalovirus (CMV) encephalitis.

As per review of the literature, this appears to be the first case of brain abscess caused by N. amikacinitolerans, a recently isolated superbug. Despite confirmation through brain biopsy later on in case 1, the initial radiological appearance was atypical, showing subtle diffusion restriction on DWI. Similarly, the authors present a case of CMV encephalitis that presented as a ring-enhancing lesion, which is extremely rare. Both cases draw attention to the reliability of neuroimaging in differentiating an abscess from a neoplasm.

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Richard Menger, Michael Wolf, Jai Deep Thakur, Anil Nanda and Anthony Martino

In 1961, President John F. Kennedy declared that the United States would send a man to the moon and safely bring him home before the end of the decade. Astronaut Michael Collins was one of those men. He flew to the moon on the historic flight of Apollo 11 while Neil Armstrong and Buzz Aldrin walked on its surface. However, this was not supposed to be the case.

Astronaut Collins was scheduled to fly on Apollo 8. While training, in 1968, he started developing symptoms of cervical myelopathy. He underwent evaluation at Wilford Hall Air Force Hospital in San Antonio and was noted to have a C5–6 disc herniation and posterior osteophyte on myelography. Air Force Lieutenant General (Dr.) Paul W. Myers performed an anterior cervical discectomy with placement of iliac bone graft. As a result, Astronaut James Lovell took his place on Apollo 8 flying the uncertain and daring first mission to the moon. This had a cascading effect on the rotation of astronauts, placing Michael Collins on the Apollo 11 flight that first landed men on the moon. It also placed Astronaut James Lovell in a rotation that exposed him to be the Commander of the fateful Apollo 13 flight.

Here, the authors chronicle the history of Astronaut Collins’ anterior cervical surgery and the impact of his procedure on the rotation of astronaut flight selection, and they review the pivotal historic nature of the Apollo 8 spaceflight. The authors further discuss the ongoing issue of cervical disc herniation among astronauts.

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Devi Prasad Patra, Amey Rajan Savardekar, Rimal Hanif Dossani, Vinayak Narayan, Nasser Mohammed and Anil Nanda

OBJECTIVE

Gamma Knife radiosurgery (GKRS) has emerged as a promising treatment modality for patients with classical trigeminal neuralgia (TN); however, considering that almost half of the patients experience post-GKRS failure or lesion recurrence, a repeat treatment is typically necessary. The existing literature does not offer clear evidence to establish which treatment modality, repeat GKRS or microvascular decompression (MVD), is superior. The present study aimed to compare the overall outcome of patients who have undergone either repeat GKRS or MVD after failure of their primary GKRS; the authors do so by conducting a systematic review and meta-analysis of the literature and analysis of data from their own institution.

METHODS

The authors conducted a systematic review and meta-analysis of the PubMed, Cochrane Library, Web of Science, and CINAHL databases to identify studies describing patients who underwent either repeat GKRS or MVD after initial failed GKRS for TN. The primary outcomes were complete pain relief (CPR) and adequate pain relief (APR) at 1 year. The secondary outcomes were rate of postoperative facial numbness and the retreatment rate. The pooled data were analyzed with R software. Bias and heterogeneity were assessed using funnel plots and I2 tests, respectively. A retrospective analysis of a series of patients treated by the authors who underwent repeat GKRS or MVD after post-GKRS failure or relapse is presented.

RESULTS

A total of 22 studies met the selection criteria and were included for final data retrieval and meta-analysis. The search did not identify any study that had directly compared outcomes between patients who had undergone repeat GKRS versus those who had undergone MVD. Therefore, the authors’ final analysis included two groups: studies describing outcome after repeat GKRS (n = 17) and studies describing outcome after MVD (n = 5). The authors’ institutional study was the only study with direct comparison of the two cohorts. The pooled estimates of primary outcomes were APR in 83% of patients who underwent repeat GKRS and 88% of those who underwent MVD (p = 0.49), and CPR in 46% of patients who underwent repeat GKRS and 72% of those who underwent MVD (p = 0.02). The pooled estimates of secondary outcomes were facial numbness in 32% of patients who underwent repeat GKRS and 22% of those who underwent MVD (p = 0.11); the retreatment rate was 19% in patients who underwent repeat GKRS and 13% in those who underwent MVD (p = 0.74). The authors’ institutional study included 42 patients (repeat GKRS in 15 and MVD in 27), and the outcomes 1 year after retreatment were APR in 80% of those who underwent repeat GKRS and 81% in those who underwent MVD (p = 1.0); CPR was achieved in 47% of those who underwent repeat GKRS and 44% in those who underwent MVD (p = 1.0). There was no difference in the rate of postoperative facial numbness or retreatment.

CONCLUSIONS

The current meta-analysis failed to identify any superiority of one treatment over the other with comparable outcomes in terms of APR, postoperative facial numbness, and retreatment rates. However, MVD was shown to provide a better chance of CPR compared with repeat GKRS.

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Sebastian R. Schreglmann, Kailash P. Bhatia, Stefan Hägele-Link, Beat Werner, Ernst Martin and Georg Kägi

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Vinayak Narayan, Amey R. Savardekar, Devi Prasad Patra, Nasser Mohammed, Jai D. Thakur, Muhammad Riaz and Anil Nanda

OBJECTIVE

Walter E. Dandy described for the first time the anatomical course of the superior petrosal vein (SPV) and its significance during surgery for trigeminal neuralgia. The patient’s safety after sacrifice of this vein is a challenging question, with conflicting views in current literature. The aim of this systematic review was to analyze the current surgical considerations regarding Dandy’s vein, as well as provide a concise review of the complications after its obliteration.

METHODS

A systematic review was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A thorough literature search was conducted on PubMed, Web of Science, and the Cochrane database; articles were selected systematically based on the PRISMA protocol and reviewed completely, and then relevant data were summarized and discussed.

RESULTS

A total of 35 publications pertaining to the SPV were included and reviewed. Although certain studies report almost negligible complications of SPV sectioning, there are reports demonstrating the deleterious effects of SPV obliteration when achieving adequate exposure in surgical pathologies like trigeminal neuralgia, vestibular schwannoma, and petroclival meningioma. The incidence of complications after SPV sacrifice (32/50 cases in the authors’ series) is 2/32 (6.2%), and that reported in various case series varies from 0.01% to 31%. It includes hemorrhagic and nonhemorrhagic venous infarction of the cerebellum, sigmoid thrombosis, cerebellar hemorrhage, midbrain and pontine infarct, intracerebral hematoma, cerebellar and brainstem edema, acute hydrocephalus, peduncular hallucinosis, hearing loss, facial nerve palsy, coma, and even death. In many studies, the difference in incidence of complications between the SPV-sacrificed group and the SPV-preserved group was significant.

CONCLUSIONS

The preservation of Dandy’s vein is a neurosurgical dilemma. Literature review and experiences from large series suggest that obliterating the vein of Dandy while approaching the superior cerebellopontine angle corridor may be associated with negligible complications. However, the counterview cannot be neglected in light of some series showing an up to 30% complication rate from SPV sacrifice. This review provides the insight that although the incidence of complications due to SPV obliteration is low, they can happen, and the sequelae might be worse than the natural history of the existing pathology. Therefore, SPV preservation should be attempted to optimize patient outcome.

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Amey R. Savardekar, Devi P. Patra, Jai D. Thakur, Vinayak Narayan, Nasser Mohammed, Papireddy Bollam and Anil Nanda

OBJECTIVE

Total tumor excision with the preservation of neurological function and quality of life is the goal of modern-day vestibular schwannoma (VS) surgery. Postoperative facial nerve (FN) paralysis is a devastating complication of VS surgery. Determining the course of the FN in relation to a VS preoperatively is invaluable to the neurosurgeon and is likely to enhance surgical safety with respect to FN function. Diffusion tensor imaging–fiber tracking (DTI-FT) technology is slowly gaining traction as a viable tool for preoperative FN visualization in patients with VS.

METHODS

A systematic review of the literature in the PubMed, Cochrane Library, and Web of Science databases was performed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, and those studies that preoperatively localized the FN in relation to a VS using the DTI-FT technique and verified those preoperative FN tracking results by using microscopic observation and electrophysiological monitoring during microsurgery were included. A pooled analysis of studies was performed to calculate the surgical concordance rate (accuracy) of DTI-FT technology for FN localization.

RESULTS

Fourteen studies included 234 VS patients (male/female ratio 1:1.4, age range 17–75 years) who had undergone preoperative DTI-FT for FN identification. The mean tumor size among the studies ranged from 29 to 41.3 mm. Preoperative DTI-FT could not visualize the FN tract in 8 patients (3.4%) and its findings could not be verified in 3 patients (1.2%), were verified but discordant in 18 patients (7.6%), and were verified and concordant in 205 patients (87.1%).

CONCLUSIONS

Preoperative DTI-FT for FN identification is a useful adjunct in the surgical planning for large VSs (> 2.5 cm). A pooled analysis showed that DTI-FT successfully identifies the complete FN course in 96.6% of VSs (226 of 234 cases) and that FN identification by DTI-FT is accurate in 90.6% of cases (205 of 226 cases). Larger studies with DTI-FT–integrated neuronavigation are required to look at the direct benefit offered by this specific technique in preserving postoperative FN function.