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Anil Nanda, Jai Deep Thakur, Ashish Sonig and Symeon Missios

OBJECTIVE

Cavernous sinus meningiomas (CSMs) represent a cohort of challenging skull base tumors. Proper management requires achieving a balance between optimal resection, restoration of cranial nerve (CN) function, and maintaining or improving quality of life. The objective of this study was to assess the pre-, intra-, and postoperative factors related to clinical and neurological outcomes, morbidity, mortality, and tumor control in patients with CSM.

METHODS

A retrospective review of a single surgeon's experience with microsurgical removal of CSM in 65 patients between January 1996 and August 2013 was done. Sekhar's classification, modified Kobayashi grading, and the Karnofsky Performance Scale were used to define tumor extension, tumor removal, and clinical outcomes, respectively.

RESULTS

Preoperative CN dysfunction was evident in 64.6% of patients. CN II deficits were most common. The greatest improvement was seen for CN V deficits, whereas CN II and CN IV deficits showed the smallest degree of recovery. Complete resection was achieved in 41.5% of cases and was not significantly associated with functional CN recovery. Internal carotid artery encasement significantly limited the complete microscopic resection of CSM (p < 0.0001). Overall, 18.5% of patients showed symptomatic recurrence after their initial surgery (mean follow-up 60.8 months [range 3–199 months]). The use of adjuvant stereotactic radiosurgery (SRS) after microsurgery independently decreased the recurrence rate (p = 0.009; OR 0.036; 95% CI 0.003–0.430).

CONCLUSIONS

Modified Kobayashi tumor resection (Grades I–IIIB) was possible in 41.5% of patients. CN recovery and tumor control were independent of extent of tumor removal. The combination of resection and adjuvant SRS can achieve excellent tumor control. Furthermore, the use of adjuvant SRS independently decreases the recurrence rates of CSM.

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Mayur Sharma, Ashish Sonig, Sudheer Ambekar and Anil Nanda

Object

The aim of this study was to analyze the incidence of adverse outcomes and inpatient mortality following resection of intramedullary spinal cord tumors by using the US Nationwide Inpatient Sample (NIS) database. The overall complication rate, length of the hospital stay, and the total cost of hospitalization were also analyzed from the database.

Methods

This is a retrospective cohort study conducted using the NIS data from 2003 to 2010. Various patient-related (demographic categories, complications, comorbidities, and median household income) and hospital-related variables (number of beds, high/low case volume, rural/urban location, region, ownership, and teaching status) were analyzed from the database. The adverse discharge disposition, in-hospital mortality, and the higher cost of hospitalization were taken as the dependent variables.

Results

A total of 15,545 admissions were identified from the NIS database. The mean patient age was 44.84 ± 19.49 years (mean ± SD), and 7938 (52%) of the patients were male. Regarding discharge disposition, 64.1% (n = 9917) of the patients were discharged to home or self-care, and the overall in-hospital mortality rate was 0.46% (n = 71). The mean total charges for hospitalization increased from $45,452.24 in 2003 to $76,698.96 in 2010. Elderly patients, female sex, black race, and lower income based on ZIP code were the independent predictors of other than routine (OTR) disposition (p < 0.001). Private insurance showed a protective effect against OTR disposition. Patients with a higher comorbidity index (OR 1.908, 95% CI 1.733–2.101; p < 0.001) and with complications (OR 2.214, 95% CI 1.768–2.772; p < 0.001) were more likely to have an adverse discharge disposition. Hospitals with a larger number of beds and those in the Northeast region were independent predictors of the OTR discharge disposition (p < 0.001). Admissions on weekends and nonelective admission had significant influence on the disposition (p < 0.001). Weekend and nonelective admissions were found to be independent predictors of inpatient mortality and the higher cost incurred to the hospitals (p < 0.001). High-volume and large hospitals, West region, and teaching hospitals were also the predictors of higher cost incurred to the hospitals (p < 0.001). The following variables (young patients, higher median household income, nonprivate insurance, presence of complications, and a higher comorbidity index) were significantly correlated with higher hospital charges (p < 0.001), whereas the variables young patients, nonprivate insurance, higher median household income, and higher comorbidity index independently predicted for inpatient mortality (p < 0.001).

Conclusions

The independent predictors of adverse discharge disposition were as follows: elderly patients, female sex, black race, lower median household income, nonprivate insurance, higher comorbidity index, presence of complications, larger hospital size, Northeast region, and weekend and nonelective admissions. The predictors of higher cost incurred to the hospitals were as follows: young patients, higher median household income, nonprivate insurance, presence of complications, higher comorbidity index, hospitals with high volume and a large number of beds, West region, teaching hospitals, and weekend and nonelective admissions.

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Jai Deep Thakur, Imad Saeed Khan, Cedric D. Shorter, Ashish Sonig, Gale L. Gardner, Bharat Guthikonda and Anil Nanda

Object

The goal of this study was to perform a systematic quantitative comparison of the surgical outcomes between cystic vestibular schwannomas (CVSs) and solid vestibular schwannomas (SVSs).

Methods

A review of English-language literature published between 1990 and 2011 was performed using various search engines including PubMed, Google Scholar, and the Cochrane database. Only studies that reported surgical results of CVSs in comparison with SVSs were included in the analysis. The primary end point of this study was surgical outcomes, defined by the following: 1) facial nerve outcomes at latest follow-up; 2) mortality rates; or 3) non–facial nerve complication index. Secondary end points included extent of resection and brainstem adherence.

Results

Nine studies comprising 428 CVSs and 1287 SVSs were included in the study. The mean age of patients undergoing surgery was 48.3 ± 6.75 and 47.1 ± 9 years for CVSs and SVSs, respectively (p = 0.8). The mean tumor diameter for CVSs was 3.9 ± 0.84 cm and that for SVSs was 3.7 ± 1.2 cm (p = 0.7). There was no significant difference in the extent of resection among CVSs and SVSs (81.2% vs 80.7%, p = 0.87) Facial nerve outcomes were significantly better in the cohort of patients with SVSs than in those with CVSs (52.1% vs 39%, p = 0.0001). The perioperative mortality rates for CVSs and SVSs were not significantly different (3% and 3.8%, respectively; p = 0.6). No significant difference was noted between the cumulative non–facial nerve complication rate (including mortality) among patients with CVSs and SVSs (24.5% and 25.6%, respectively; p = 0.75)

Conclusions

Facial nerve outcomes are worse in patients undergoing resection for CVSs than in patients undergoing resection for SVSs. There were no significant differences in the extent of resection or postoperative morbidity and mortality rates between the cohorts of patients with vestibular schwannomas.

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Ashish Sonig, Jai Deep Thakur, Prashant Chittiboina, Imad Saeed Khan and Anil Nanda

Object

Various factors have been reported in literature to be associated with the development of posttraumatic meningitis. There is a paucity of data regarding skull fractures and facial fractures leading to CSF leaks and their association with the development of meningitis. The primary objective of this study was to analyze the US Nationwide Inpatient Sample (NIS) database to elucidate the factors associated with the development of posttraumatic meningitis. A secondary goal was to analyze the overall hospitalization cost related to posttraumatic meningitis and factors associated with that cost.

Methods

The NIS database was analyzed to identify patients admitted to hospitals with a diagnosis of head injury from 2005 through 2009. This data set was analyzed to assess the relationship of various clinical parameters that may affect the development of posttraumatic meningitis using binary logistic regression models. Additionally, the overall hospitalization cost for the head injury patients who did not undergo any neurosurgical intervention was further categorized into quartile groups, and a regression model was created to analyze various factors responsible for escalating the overall cost of the hospital stay.

Results

A total of 382,267 inpatient admissions for head injury were analyzed for the 2005–2009 period. Meningitis was reported in 0.2% of these cases (708 cases). Closed skull base fractures, open skull base fractures, cranial vault fractures, and maxillofacial fractures were reported in 20,524 (5.4%), 1089 (0.3%), 5064 (1.3%), and 88,649 (23.2%) patients, respectively. Among these patients with fractures, meningitis was noted in 0.17%, 0.18%, 0.05%, and 0.10% admissions, respectively. Cerebrospinal fluid rhinorrhea was reported in 453 head injury patients (0.1%) and CSF otorrhea in 582 (0.2%). Of the patients reported to have CSF rhinorrhea, 35 (7.7%) developed meningitis, whereas in the cohort with CSF otorrhea, 15 patients (2.6%) developed meningitis. Cerebrospinal fluid rhinorrhea (p < 0.001, OR 22.8, 95% CI 15.6–33.3), CSF otorrhea (p < 0.001, OR 9.2, 95% CI 5.2–16.09), and major neurosurgical procedures (p < 0.001, OR 5.6, 95% CI 4.8–6.5) were independent predictors of meningitis. Further, CSF rhinorrhea (p < 0.001, OR 2.0, 95% CI 1.6–2.7), CSF otorrhea (p < 0.001, OR 2.3, 95% CI 1.9–2.7), and posttraumatic meningitis (p < 0.001, OR 3.1, 95% CI 2.5–3.8) were independent factors responsible for escalating the cost of head injury in cases not requiring any major neurosurgical intervention.

Conclusions

Cerebrospinal fluid rhinorrhea and CSF otorrhea are independent predictors of posttraumatic meningitis. Furthermore, meningitis and CSF fistulas may independently lead to significantly increased cost of hospitalization in head injury patients not undergoing any major neurosurgical intervention.

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Ashish Sonig, Jai Thakur, Monica Grass, Imad Saeed Khan, Viraj Gandhi and Anil Nanda

The anatomical description of the fifth cranial nerve ganglion lacked detail before the work of Antonius Balthazar Raymundus Hirsch (1744–1778). Hirsch used new dissection techniques that resulted in the most meticulous report of the trigeminal ganglion (the gasserian ganglion) to have been reported. In 1765, the 21-year-old published these findings in a thesis, Paris Quinti Nervorum Encephali Disquisitio Anatomica In Quantum Ad Ganglion Sibi Proprium, Semilunare, Et Ad Originem Nervi Intercostalis Pertinet [An anatomical inquiry of the fifth pair of the nerves of the brain, so far as it relates to the ganglion unto itself, the semilunar, and to the source of the intercostal nerve].

Hirsch wrote his thesis as a paean to his ailing teacher, Johann Lorenz Gasser, but Gasser died before Hirsch was able to defend his thesis. Thereafter, Hirsch applied to teach anatomy at his alma mater, the University of Vienna, but the university did not consider his application, deeming him too young for the position. Oddly, Hirsch died at the young age of 35. For the present paper, the library at the University of Vienna (Universität Wien), Austria, was contacted, and Anton Hirsch's thesis was digitized and subsequently translated from Latin into English. The authors here attempt to place the recognition of the fifth cranial nerve ganglion within a historical perspective and trace the trajectory of its anatomical descriptions.

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Ashish Sonig, Hussain Shallwani, Bennett R. Levy, Hakeem J. Shakir and Adnan H. Siddiqui

OBJECTIVE

Publication has become a major criterion of success in the competitive academic environment of neurosurgery. This is the first study that has used departmental h index–and e index–based matrices to assess the academic output of neuroendovascular, neurointerventional, and interventional radiology fellowship programs across the continental US.

METHODS

Fellowship program listings were identified from academic and organization websites. Details for 37 programs were available. Bibliometric data for these programs were gathered from the Thomson Reuters Web of Science database. Citations for each publication from the fellowship's parent department were screened, and the h and e indices were calculated from non–open-surgical, central nervous system vascular publications. Variables including “high-productivity” centers, fellowship–comprehensive stroke center affiliation, fellowship accreditation status, neuroendovascular h index, e index (h index supplement), h10 index (publications during the last 10 years), and departmental faculty-based h indices were created and analyzed.

RESULTS

A positive correlation was seen between the neuroendovascular fellowship h index and corresponding h10 index (R = 0.885; p < 0.0001). The mean, median, and highest faculty-based h indices exhibited positive correlations with the neuroendovascular fellowship h index (R = 0.662, p < 0.0001; R = 0.617, p < 0.0001; and R = 0.649, p < 0.0001, respectively). There was no significant difference (p = 0.824) in the median values for the fellowship h index based on comprehensive stroke center affiliation (30 of 37 programs had such affiliations) or accreditation (18 of 37 programs had accreditation) (p = 0.223). Based on the quartile analysis of the fellowship h index, 10 of 37 departments had an neuroendovascular h index of ≥ 54 (“high-productivity” centers); these centers had significantly more faculty (p = 0.013) and a significantly higher mean faculty h index (p = 0.0001).

CONCLUSIONS

The departmental h index and analysis of its publication topics can be used to calculate the h index of an associated subspecialty. The analysis was focused on the neuroendovascular specialty, and this methodology can be extended to other neurosurgical subspecialties. Individual faculty research interest is directly reflected in the research productivity of a department. High-productivity centers had significantly more faculty with significantly higher individual h indices. The current systems for neuroendovascular fellowship program accreditation do not have a meaningful impact on academic productivity.

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Ashish Sonig, Imad Saeed Khan, Rishi Wadhwa, Jai Deep Thakur and Anil Nanda

Object

Hospitalization cost and patient outcome after acoustic neuroma surgery depend on several factors. There is a paucity of data regarding the relationship between demographic features such as age, sex, race, insurance status, and patient outcome. Apart from demographic factors, there are several hospital-related factors and regional issues that can affect outcomes and hospital costs. To the authors' knowledge, no study has investigated the issue of regional disparity across the country in terms of cost of hospitalization and discharge disposition.

Methods

The authors analyzed the Nationwide Inpatient Sample (NIS) database over the years 2005–2009. Several variables were analyzed from the database, including patient demographics, comorbidities, and surgical complications. Hospital variables, such as bedsize, rural/urban location, teaching status, federal or private ownership, and the region, were also examined. Patient outcome and increased hospitalization costs were the dependent variables studied.

Results

A total of 2589 admissions from 242 hospitals were analyzed from the NIS data over the years 2005–2009. The mean age was 48.99 ± 13.861 years (± SD), and 304 (11.7%) of the patients were older than 65 years. The cumulative cost incurred by the hospitals from 2005 to 2009 was $948.77 million. The mean expenditure per admission was $76,365.09 ± $58,039.93. The mean total charges per admission rose from $59,633.00 in 2005 to $97,370.00 in 2009. The factors that predicted most significantly with other than routine (OTR) disposition outcome were age older than 65 years (OR 2.22, 95% CI 1.411–3.518; p < 0.001), aspiration pneumonia (OR 16.085, 95% CI 4.974–52.016; p < 0.001), and meningitis (OR 11.299, 95% CI 3.126–40.840; p < 0.001). When compared with patients with Medicare and Medicaid, patients with private insurance had a protective effect against OTR disposition outcome. Higher comorbidities predicted independently for OTR disposition outcome (OR 1.409, 95% CI 1.072–1.852; p = 0.014). The West region predicted negatively for OTR disposition outcome. Large hospitals were independently associated with higher hospital charges (OR 4.269, 95% CI 3.106–5.867; p < 0.001). The West region had significantly higher (p < 0.001) mean hospital charges than the other regions. Patient factors such as meningitis and aspiration pneumonia were strong independent predictors of increased hospital charges (p < 0.001). Higher comorbidities (OR 1.297, 95% CI 1.036–1.624; p = 0.023) and presence of neurofibromatosis Type 2 (OR 2.341, 95% CI 1.479–3.707; p < 0.001) were associated with higher hospital charges.

Conclusions

The authors' study shows that several factors can affect patient outcome and hospital charges for patients who have undergone acoustic neuroma surgery. Factors such as younger age, higher ZIP code income, less comorbidity, private insurance, elective surgery, and the West region predicted for better disposition outcome. However, the West region, higher comorbidities, and weekend admissions were associated with higher hospitalization costs.

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Jai Deep Thakur, Ashish Sonig, Prashant Chittiboina, Imad Saeed Khan, Rishi Wadhwa and Anil Nanda

Humphrey Ridley, M.D. (1653–1708), is a relatively unknown historical figure, belonging to the postmedieval era of neuroanatomical discovery. He was born in the market town of Mansfield, 14 miles from the county of Nottinghamshire, England. After studying at Merton College, Oxford, he pursued medicine at Leiden University in the Netherlands. In 1688, he was incorporated as an M.D. at Cambridge. Ridley authored the first original treatise in English language on neuroanatomy, The Anatomy of the Brain Containing its Mechanisms and Physiology: Together with Some New Discoveries and Corrections of Ancient and Modern Authors upon that Subject.

Ridley described the venous anatomy of the eponymous circular sinus in connection with the parasellar compartment. His methods were novel, unique, and effective. To appreciate the venous anatomy, he preferred to perform his anatomical dissections on recently executed criminals who had been hanged. These cadavers had considerable venous engorgement, which made the skull base venous anatomy clearer. To enhance the appearance of the cerebral vasculature further, he used tinged wax and quicksilver in the injections. He set up experimental models to answer questions definitively, in proving that the arachnoid mater is a separate meningeal layer. The first description of the subarachnoid cisterns, blood-brain barrier, and the fifth cranial nerve ganglion with its branches are also attributed to Ridley.

This historical vignette revisits Ridley's life and academic work that influenced neuroscience and neurosurgical understanding in its infancy. It is unfortunate that most of his novel contributions have gone unnoticed and uncited. The authors hope that this article will inform the neurosurgical community of Ridley's contributions to the field of neurosurgery.

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Imad Saeed Khan, Ashish Sonig, Jai Deep Thakur, Papireddy Bollam and Anil Nanda

Object

Transforaminal lumbar interbody fusion (TLIF) has been increasingly used to treat degenerative spine disease, including that in patients in whom earlier decompressive procedures have failed. Reexploration in these cases is always challenging and is thought to pose a higher risk of complications. To the best of the authors' knowledge, there are no current studies specifically analyzing the effects of previous lumbar decompressive surgeries on the complication rates of open TLIF.

Methods

The authors performed a retrospective study of surgeries performed by a single surgeon. A total of 187 consecutive patients, in whom the senior author (A.N.) had performed open TLIF between January 2007 and January 2011, met the inclusion criteria. The patients were divided into two groups (primary and revision TLIF) for the comparison of perioperative complications.

Results

Overall, the average age of the patients was 49.7 years (range 18–80 years). Of the 187 patients, 73 patients had no history of lumbar surgery and 114 were undergoing revision surgery. Fifty-four patients (28.9%) had a documented complication intraoperatively or postoperatively. There was no difference in the rate on perioperative complications between the two groups (overall, medical, wound related, inadvertent dural tears [DTs], or neural injury). Patients who had undergone more than one previous lumbar surgery were, however, more likely to have suffered from DTs (p = 0.054) and neural injuries (p = 0.007) compared with the rest.

Conclusions

In the hands of an experienced surgeon, revision open TLIF does not necessarily increase the risk of perioperative complications compared with primary TLIF. Two or more previous lumbar decompressive procedures, however, increase the risk of inadvertent DTs and neural injury.

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Richard P. Menger, David E. Connor Jr., Jai Deep Thakur, Ashish Sonig, Elainea Smith, Bharat Guthikonda and Anil Nanda

Object

Complications following lumboperitoneal (LP) shunting have been reported in 18% to 85% of cases. The need for multiple revision surgeries, development of iatrogenic Chiari malformation, and frequent wound complications have prompted many to abandon this procedure altogether for the treatment of idiopathic benign intracranial hypertension (pseudotumor cerebri), in favor of ventriculoperitoneal (VP) shunting. A direct comparison of the complication rates and health care charges between first-choice LP versus VP shunting is presented.

Methods

The Nationwide Inpatient Sample database was queried for all patients with the diagnosis of benign intracranial hypertension (International Classification of Diseases, Ninth Revision, code 348.2) from 2005 to 2009. These data were stratified by operative intervention, with demographic and hospitalization charge data generated for each.

Results

A weighted sample of 4480 patients was identified as having the diagnosis of idiopathic intracranial hypertension (IIH), with 2505 undergoing first-time VP shunt placement and 1754 undergoing initial LP shunt placement. Revision surgery occurred in 3.9% of admissions (n = 98) for VP shunts and in 7.0% of admissions (n = 123) for LP shunts (p < 0.0001). Ventriculoperitoneal shunts were placed at teaching institutions in 83.8% of cases, compared with only 77.3% of first-time LP shunts (p < 0.0001). Mean hospital length of stay (LOS) significantly differed between primary VP (3 days) and primary LP shunt procedures (4 days, p < 0.0001). The summed charges for the revisions of 92 VP shunts ($3,453,956) and those of the 6 VP shunt removals ($272,484) totaled $3,726,352 over 5 years for the study population. The summed charges for revision of 70 LP shunts ($2,229,430) and those of the 53 LP shunt removals ($3,125,569) totaled $5,408,679 over 5 years for the study population.

Conclusions

The presented results appear to call into question the selection of LP shunt placement as primary treatment for IIH, as this procedure is associated with a significantly greater likelihood of need for shunt revision, increased LOS, and greater overall charges to the health care system.