Emotional Lability as a Symptom of Extra-axial Posterior Fossa Tumors: a Case-Control Review of Neuroanatomy and Patient-Reported Quality of Life

Introduction  Emotional lability (EL), the uncontrollable and unmotivated expression of emotion, is a rare and distressing symptom of brainstem compression. In published case reports, EL from an extra-axial posterior fossa tumor was alleviated by tumor resection. The primary aim herein was to radiographically establish the degree of compression from mass lesions onto brainstem structures. Secondarily, we compared changes in patient-reported quality of life (QOL) pre- and postoperatively. Methods  A retrospective review of posterior fossa tumors treated between 2002 and 2018 at Vancouver General Hospital revealed 11 patients with confirmed EL. Each case was matched to three controls. A lateral brainstem compression scale characterized mass effect at the level of the medulla, pons, and midbrain in preoperative axial T2-weighted fluid-attenuated inversion recovery magnetic resonance imaging (FLAIR MRI) scans. Compression and clinical variables were compared between patient groups. Short Form-36 version 1 health surveys were retrospectively obtained from patient charts to compare pre- versus postoperative changes in survey scores between EL and control patients. Results  EL symptoms ceased postoperatively for all EL patients. EL tumors exert greater compression onto the pons ( p  = 0.03) and EL patients more commonly have cerebellar findings preoperatively ( p  = 0.003). Patients with EL-causing tumors experienced greater improvement postoperatively in "Health Change" ( p  = 0.05), which was maintained over time. Conclusion  Findings suggest that compression onto the pons inhibits control over involuntary, stereotyped expression of emotion. This adds to evidence that EL may be attributed to cerebellum deafferentation from cortical and limbic structures through the basis pontis, leading to impaired modulation of emotional response. QOL results augment benefits of offering patients EL-alleviating tumor resection surgery.

neuroGPT-X: toward a clinic-ready large language model

OBJECTIVE

The objective was to assess the performance of a context-enriched large language model (LLM) compared with international neurosurgical experts on questions related to the management of vestibular schwannoma. Furthermore, another objective was to develop a chat-based platform incorporating in-text citations, references, and memory to enable accurate, relevant, and reliable information in real time.

METHODS

The analysis involved 1) creating a data set through web scraping, 2) developing a chat-based platform called neuroGPT-X, 3) enlisting 8 expert neurosurgeons across international centers to independently create questions (n = 1) and to answer (n = 4) and evaluate responses (n = 3) while blinded, and 4) analyzing the evaluation results on the management of vestibular schwannoma. In the blinded phase, all answers were assessed for accuracy, coherence, relevance, thoroughness, speed, and overall rating. All experts were unblinded and provided their thoughts on the utility and limitations of the tool. In the unblinded phase, all neurosurgeons provided answers to a Likert scale survey and long-answer questions regarding the clinical utility, likelihood of use, and limitations of the tool. The tool was then evaluated on the basis of a set of 103 consensus statements on vestibular schwannoma care from the 8th Quadrennial International Conference on Vestibular Schwannoma.

RESULTS

Responses from the naive and context-enriched Generative Pretrained Transformer (GPT) models were consistently rated not significantly different in terms of accuracy, coherence, relevance, thoroughness, and overall performance, and they were often rated significantly higher than expert responses. Both the naive and content-enriched GPT models provided faster responses to the standardized question set than expert neurosurgeon respondents (p < 0.01). The context-enriched GPT model agreed with 98 of the 103 (95%) consensus statements. Of interest, all expert surgeons expressed concerns about the reliability of GPT in accurately addressing the nuances and controversies surrounding the management of vestibular schwannoma. Furthermore, the authors developed neuroGPT-X, a chat-based platform designed to provide point-of-care clinical support and mitigate the limitations of human memory. neuroGPT-X incorporates features such as in-text citations and references to enable accurate, relevant, and reliable information in real time.

CONCLUSIONS

The present study, with its subspecialist-level performance in generating written responses to complex neurosurgical problems for which evidence-based consensus for management is lacking, suggests that context-enriched LLMs show promise as a point-of-care medical resource. The authors anticipate that this work will be a springboard for expansion into more medical specialties, incorporating evidence-based clinical information and developing expert-level dialogue surrounding LLMs in healthcare.

Vertebral Artery Mobilization During Transcondylar Extreme Far Lateral Approach for Excision of Large Foramen Magnum Meningioma: 2-Dimensional Operative Video

Foramen magnum meningiomas are challenging lesions owing to their proximity to the lower brainstem, vertebrobasilar system, and lower cranial nerves.1,2 Tumor size, origin, morphology, relationship to neurovascular structures, and bony anatomy determine the optimal surgical approach.2,3 Classically, far lateral approaches have been the workhorse approach to the foramen magnum. Variations of the far lateral including transcondylar and extended transcondylar (paracondylar), with or without transposition of the vertebral artery, are sometimes used for a more lateral approach to the brainstem and clivus. Here, we present a 60-year-old male patient presenting with a large foramen magnum meningioma. Preoperative workup includes computed tomography and MRI with angiography to assess for posterior circulation dominance, anatomic variants including posterior inferior cerebellar artery origin, venous, and bony anatomy.1,4 An extreme far lateral provides access anterior to the vertebral artery to extend exposure beyond the standard far lateral approach. This comprised transcondylar drilling, bony mobilization of the V3 Vertebral artery from C1 foramen transversarium, and dural mobilization of vertebral artery with a dural cuff at its site of dural entry. The patient tolerated the procedure, gross total resection was achieved, and the patient was discharged home. This video demonstrates in detail the steps of exposure, condylar drilling, vertebral artery transposition, and dural opening. These maneuvers can be difficult to conceptualize yet are key to successful extended transcondylar exposure. The patient gave informed consent for surgery and video recording. Institutional Review Board approval was deemed unnecessary.

International Tuberculum Sellae Meningioma Study: Surgical Outcomes and Management Trends

BACKGROUND AND OBJECTIVES

Tuberculum sellae meningiomas (TSMs) can be resected through transcranial (TCA) or expanded endonasal approach (EEA). The objective of this study was to report TSM management trends and outcomes in a large multicenter cohort.

METHODS

This is a 40-site retrospective study using standard statistical methods.

RESULTS

In 947 cases, TCA was used 66.4% and EEA 33.6%. The median maximum diameter was 2.5 cm for TCA and 2.1 cm for EEA ( P < .0001). The median follow-up was 26 months. Gross total resection (GTR) was achieved in 70.2% and did not differ between EEA and TCA ( P = .5395). Vision was the same or better in 87.5%. Vision improved in 73.0% of EEA patients with preoperative visual deficits compared with 57.1% of TCA patients ( P < .0001). On multivariate analysis, a TCA (odds ratio [OR] 1.78, P = .0258) was associated with vision worsening, while GTR was protective (OR 0.37, P < .0001). GTR decreased with increased diameter (OR: 0.80 per cm, P = .0036) and preoperative visual deficits (OR 0.56, P = .0075). Mortality was 0.5%. Complications occurred in 23.9%. New unilateral or bilateral blindness occurred in 3.3% and 0.4%, respectively. The cerebrospinal fluid leak rate was 17.3% for EEA and 2.2% for TCA (OR 9.1, P < .0001). The recurrence rate was 10.9% (n = 103). Longer follow-up (OR 1.01 per month, P < .0001), World Health Organization II/III (OR 2.20, P = .0262), and GTR (OR: 0.33, P < .0001) were associated with recurrence. The recurrence rate after GTR was lower after EEA compared with TCA (OR 0.33, P = .0027).

CONCLUSION

EEA for appropriately selected TSM may lead to better visual outcomes and decreased recurrence rates after GTR, but cerebrospinal fluid leak rates are high, and longer follow-up is needed. Tumors were smaller in the EEA group, and follow-up was shorter, reflecting selection, and observation bias. Nevertheless, EEA may be superior to TCA for appropriately selected TSM.

International Tuberculum Sellae Meningioma Study: Preoperative Grading Scale to Predict Outcomes and Propensity-Matched Outcomes by Endonasal Versus Transcranial Approach

BACKGROUND AND OBJECTIVES

Tuberculum sellae meningiomas are resected via an expanded endonasal (EEA) or transcranial approach (TCA). Which approach provides superior outcomes is debated. The Magill-McDermott (M-M) grading scale evaluating tumor size, optic canal invasion, and arterial involvement remains to be validated for outcome prediction. The objective of this study was to validate the M-M scale for predicting visual outcome, extent of resection (EOR), and recurrence, and to use propensity matching by M-M scale to determine whether visual outcome, EOR, or recurrence differ between EEA and TCA.

METHODS

Forty-site retrospective study of 947 patients undergoing tuberculum sellae meningiomas resection. Standard statistical methods and propensity matching were used.

RESULTS

The M-M scale predicted visual worsening (odds ratio [OR]/point: 1.22, 95% CI: 1.02-1.46, P = .0271) and gross total resection (GTR) (OR/point: 0.71, 95% CI: 0.62-0.81, P < .0001), but not recurrence ( P = .4695). The scale was simplified and validated in an independent cohort for predicting visual worsening (OR/point: 2.34, 95% CI: 1.33-4.14, P = .0032) and GTR (OR/point: 0.73, 95% CI: 0.57-0.93, P = .0127), but not recurrence ( P = .2572). In propensity-matched samples, there was no difference in visual worsening ( P = .8757) or recurrence ( P = .5678) between TCA and EEA, but GTR was more likely with TCA (OR: 1.49, 95% CI: 1.02-2.18, P = .0409). Matched patients with preoperative visual deficits who had an EEA were more likely to have visual improvement than those undergoing TCA (72.9% vs 58.4%, P = .0010) with equal rates of visual worsening (EEA 8.0% vs TCA 8.6%, P = .8018).

CONCLUSION

The refined M-M scale predicts visual worsening and EOR preoperatively. Preoperative visual deficits are more likely to improve after EEA; however, individual tumor features must be considered during nuanced approach selection by experienced neurosurgeons.

Correlation of Pituitary Descent and Diabetes Insipidus After Transsphenoidal Pituitary Macroadenoma Resection

BACKGROUND

Endoscopic transsphenoidal surgery remains the technique of choice for resection of pituitary adenoma. Postoperative diabetes insipidus (DI) is most often transient and observed in 1.6% to 34% of patients, whereas permanent DI has been reported in 0% to 2.7% of patients. The proposed mechanism was the transduction of traction forces exerted by the surgeon on the descended diaphragma sellae and through the pituitary stalk.

OBJECTIVE

To quantify and correlate the degree of pituitary gland descent with postoperative DI.

METHODS

Of 374 patients who underwent transsphenoidal resection of a pituitary adenoma between 2010 and 2020 at our institution, we report a cohort of 30 patients (Group A) DI. We also report a matched cohort by tumor volume of 30 patients who did not develop DI (Group B). We quantified the tension on the pituitary stalk by calculating pituitary descent interval (PDI) by comparing preoperative and postoperative position of the pituitary gland and using Pythagoras' formula where , with craniocaudal (CC) and anterior-posterior (AP) representing measurements of pituitary translation in respective directions after resection.

RESULTS

Patients who developed DI had significantly greater pituitary gland translations in the craniocaudal (23.0 vs 16.3 mm, P = .0015) and anteroposterior (2.4 vs 1.5 mm, P = .0168) directions. Furthermore, Group A had a statistically greater PDI, which was associated with development of DI (23.2 vs 16.6 mm, P = .0017).

CONCLUSION

We were able to quantify pituitary descent and subsequent tension on the pituitary stalk, while also associating it with development of postoperative DI after pituitary adenoma resection.

Large Subependymoma Inferior to the Cerebellopontine Angle With Significant Obstructive Hydrocephalus: A Case Report on an Extremely Rare Tumor

Subependymomas are rare yet benign tumors that are commonly found within the ventricular system. We describe the case of a 51-year-old male presenting with hydrocephalus and progressive headaches found to have a right cerebellopontine angle (CPA) lesion encasing multiple blood vessels and cranial nerves (CN). The lesion was resected subtotally via a retrosigmoid approach and was found to be a subependymoma. CPA subependymomas are extremely rare lesions. The neuroimaging and histopathological findings as well as a comprehensive literature review of similar cases are discussed.

The Unified Visual Function Scale Assessments Show Inter- and Intraobserver Agreement and Correlate with Patient Quality of Life in Skull Base Parasellar Tumors

Background The authors have previously described the Unified Visual Function Scale (UVFS). Here, we assessed intra- and interobserver reliability of the scale, and investigated correlations with patient quality of life (QoL).

Methods Eight healthcare practitioners independently applied the UVFS in 20 representative cases from our parasellar meningioma series. Scoring was compared with consensus grades assigned by lead authors. Inter- and intraobserver agreement was measured using intraclass correlation coefficient (ICC), Fleiss's κ, and Cohen's κ, respectively. Patient QoL was assessed Visual Function Questionnaire 25 (VFQ-25) or Activities of Daily Vision Scale (ADVS), and correlated with UVFS grades for each eye.

Results The interobserver ICC was 0.734 (95% confidence interval [CI]: 0.652–0.811), with Fleiss's κ of 0.758, 0.691, and 0.899 for grades A, B, and C, respectively. The intraobserver ICC was 0.758 (95% CI: 0.638–0.872), and Fleiss's κ was 0.604, 0.268, and 0.910 for grades A, B, and C respectively. The Cohen's κ for agreement between UVFS category grades and consensus grades was 0.816 (95 CI: 0.698–0.934). Survey response rate was 51% (27/53). The UVFS demonstrated strong correlation with VFQ-25 subdivisions general vision (r = 0.7712), near activities (r = 0.7262), peripheral vision (r = 0.6722), and driving (r = 0.6608), and also demonstrated strong correlation with the overall ADVS score (r = 0.5902).

Conclusion This study shows that the UVFS is valid within a small subset of observers, and accurately reflects patient QoL. It is robust and practical, which make it suitable for broad implementation.

ICA Occlusion by an ACTH- secreting pituitary adenoma post-TSS and irradiation

Occlusion of intracranial arteries by a pituitary adenoma with ensuing infarction is a rare occurrence. In this case study, we show the instance of a pituitary  macroadenoma and apoplexy causing mechanical obstruction of the internal carot- id artery with consequent infarction following transphenoidal surgery (TSS) and ra- diation therapy in a patient with Cushing’s disease. we report a 44-year-old woman  presented with amenorrhea and headaches. Necessary investigations, resection by  TSS, and microscopic examination revealed an adenocorticotropin (ACTH)-secret- ing pituitary macroadenoma. The pituitary tumour recurred in subsequent years,  resulting in the development of Cushing’s disease and syndrome. despite two more  transphenoidal surgeries, radiotherapy, and medical suppressive therapy, the pi- tuitary adenoma continued to enlarge, and the hypercortisolemia and Cushingoid  symptoms persisted. A craniotomy was arranged as the next step in the treatment strategy. Only hours prior to the scheduled surgery, the patient developed left-sided hemiplegia, was diagnosed with acute occlusion of the right ICA and underwent an emergency bifrontal craniotomy with evacuation of the tumour and decompression.  Pathological examination revealed evidence of apoplexy in the ACTH-secreting pi- tuitary adenoma. This case demonstrates the vast scope of complications that can  arise from pituitary adenomas despite combination therapy and forewarns clinicians to be prepared to manage these infrequent but conceivable occurrences.

A novel scale for describing visual outcomes in patients following resection of lesions affecting the optic apparatus: the Unified Visual Function Scale

OBJECTIVEHistorically, descriptions of visual acuity and visual field change following intracranial procedures have been very rudimentary. Clinicians and researchers have often used basic descriptions, such as "improved," "worsened," and "unchanged," to describe outcomes following resections of tumors affecting the optic apparatus. These descriptors are vague, difficult to quantify, and challenging to apply in a clinical perspective. Several groups have attempted to combine visual acuity and visual fields into a single assessment score, but these are not user-friendly. The authors present a novel way to describe a patient's visual function as a combination of visual acuity and visual field assessment that is simple to use and can be used by surgeons and researchers to gauge visual outcomes following tumor resection.METHODSVisual acuity and visual fields were combined into 3 categories designed around the definitions of legal blindness and fitness to drive in Canada. The authors then applied the scale (the Unified Visual Function Scale, or UVFS) to their previously published case series of perisellar meningiomas to document and test overall visual outcomes for patients undergoing tumor resection. The results were compared with previously documented visual loss scales in the literature.RESULTSUsing the UVFS the authors were able to capture the overall visual change; the scale was sensitive enough to define the overall visual improvement or worsening quantitatively, using categories that are clinically relevant and understandable.CONCLUSIONSThe UVFS is a robust way to assess a patient's vision, combining visual fields and acuity. The implementation of pre- and postoperative assessment is sensitive enough to assess overall change while also providing clinically relevant information for surgeons, and allows for comparisons between treatment groups.

Differential Recovery in Early- and Late-Onset Delayed Facial Palsy Following Vestibular Schwannoma Resection

BACKGROUND

Delayed facial palsy (DFP) after resection of vestibular schwannomas (VS) is worsening of facial nerve function after an initially normal postoperative result.

OBJECTIVE

To characterize different types of DFP, compare recovery rates, and review of series of outcomes in patients following resection of VS.

METHODS

Between 2001 and 2017, 434 patients (51% female) with VS underwent resection. We categorized the patients who developed facial palsy into groups based on timing of onset after surgery, immediate facial palsy (IFP), early-onset DFP (within 48 h), and late-onset DFP (after 48 h). Introduction of facial nerve motor-evoked potentials (fMEP) in 2002 and a change of practice utilizing perioperative minocycline in 2005 allowed for historical analysis of these interventions.

RESULTS

Mean age of study cohort was 49.1 yr (range 13-81 yr), with 19.8% developing facial palsy. The late-onset DFP group demonstrated a significantly faster recovery than the early-onset DFP group (2.8 ± 0.5 vs 47 ± 8 wk, P &lt; .0001), had prolonged latency to palsy onset after initiating perioperative minocycline (7.3 vs 12.5 d, P = .001), and had a nonsignificant trend towards faster recovery from facial palsy with use of minocycline (2.6 vs 3.4 wk, P = .11).

CONCLUSION

Given the timings, it is likely axonal degeneration is responsible for early-onset DFP, while demyelination and remyelination lead to faster facial nerve recovery in late-onset DFP. Reported anti-apoptotic properties of minocycline could account for the further delay in onset of DFP, and possibly reduce the rate and duration of DFP in the surgical cohort.

Sudden neurological deterioration due to repeated intratumoral hemorrhage in a patient with a vestibular schwannoma

Vestibular schwannomas (VS) are the most common tumors involving the cerebellopontine angle (CPA) and the internal auditory canal (IAC). These tumors are usually slow-growing and commonly present with cranial nerve dysfunction such as hearing loss. Repeated intratumoral hemorrhage (ITH) is extremely rare with only four cases previously reported. We report the case of a 30 year old female with a right sided CP angle tumor who presented with vertigo and ataxia due to ITH. Her symptoms initially improved; however, three weeks later, she had acute onset of facial palsy and imaging confirmed rebleeding. Surgical pathology reported typical features of schwannoma. A literature review performed using the PubMed and EMBASE databases yielded four previous reports. A summary of these cases is presented and the features of ITH are discussed. Patients affected by repeated ITH present with sudden headache and ataxia. Rapid worsening of cranial nerve dysfunction such as hearing loss or facial nerve palsy is suggestive of ITH.

Natural History, Multimodal Management, and Quality of Life Outcomes of Trigeminal Schwannomas

Background  Trigeminal schwannomas are the second most common among intracranial schwannomas. These can arise from anywhere between the root and the distal extracranial branches of the trigeminal nerve. Clinical presentation depends on location and size, including but not limited to facial hypesthesia or pain, headaches, dizziness, ataxia, and diplopia. Literature is strikingly scant discussing the natural history of these lesions, while the treatment goals are heavily dependent on tumor presentation. Management decisions must be individualized to each tumor and each patient, while attempting to maximize the quality of life. We present the natural history of these lesions as well as their management by surgical resection or radiation therapy, and report long-term quality of life outcomes. Methods  Between 2001 and 2015, 24 patients (66.7% female) with trigeminal schwannomas were diagnosed and managed at Vancouver General Hospital. We analyzed the clinical presentation, surgical results, resection rates, patient quality of life, and complications. To complete the evaluation, we prospectively collected 36-Item Short Form Health Survey (SF-36) quality of life assessments for comparison. Results  We identified 12 patients treated with a craniotomy and surgical resection, 4 were treated with radiation therapy, while 8 patients were followed by observation. Mean age of study cohort was 49.2 years (range, 23-79 years), and most patients presented with facial hypesthesia (54.2%) and headaches (37.5%), while 37.5% were incidental findings. There were no major differences in patient demographics between the three groups. Patients offered surgery had larger lesions (mean diameter, 3.4 ± 1.1 cm) when compared with those that were irradiated or observed, and were more likely to have extracranial extension. Overall patient quality of life improved following treatment (ΔSF-36 + 12.9) at 3.9 years. Conclusions  The treatment goals of trigeminal schwannomas focus on improvement in neurologic symptoms, relief of mass effect, and preservation of cranial nerve function. We demonstrate that smaller lesions found incidentally with minimal symptoms can be followed safely with serial imaging, with 1 of 9 (11.1%) progressing to require treatment over the course of 7.1 years. Management of trigeminal schwannomas should be individualized with an involvement of a multidisciplinary skull base team.

Adult Craniopharyngioma: Case Series, Systematic Review, and Meta-Analysis

BACKGROUND

The optimal therapeutic approach for adult craniopharyngioma remains controversial. Some advocate for gross total resection (GTR), while others advocate for subtotal resection followed by adjuvant radiotherapy (STR + XRT).

OBJECTIVE

To conduct a systematic review and meta-analysis assessing the rate of recurrence in the follow-up of 3 yr in adult craniopharyngioma stratified by extent of resection and presence of adjuvant radiotherapy.

METHODS

MEDLINE (1946-July 1, 2016) and EMBASE (1980-June 30, 2016) were systematically reviewed. From1975 to 2013, 33 patients were treated with initial surgical resection for adult onset craniopharyngioma at our center and were reviewed for inclusion in this study.

RESULTS

Data from 22 patients were available for inclusion as a case series in the systematic review. Eligible studies (n = 21) were identified from the literature in addition to a case series of our institutional experience. Three groups were available for analysis: GTR, STR + XRT, and STR. The rates of recurrence were 17%, 27%, and 45%, respectively. The risk of developing recurrence was significant for GTR vs STR (odds ratio [OR]: 0.24, 95% confidence interval [CI]: 0.15-0.38) and STR + XRT vs STR (OR: 0.20, 95% CI: 0.10-0.41). Risk of recurrence after GTR vs STR + XRT did not reach significance (OR: 0.63, 95% CI: 0.33-1.24, P = .18).

CONCLUSION

This is the first and largest systematic review focusing on the rate of recurrence in adult craniopharyngioma. Although the rates of recurrence are favoring GTR, difference in risk of recurrence did not reach significance. This study provides guidance to clinicians and directions for future research with the need to stratify outcomes per treatment modalities.

Craniotomy for perisellar meningiomas: comparison of simple (appropriate for endoscopic approach) versus complex anatomy and surgical outcomes

OBJECTIVE

Microsurgical resection of perisellar meningiomas has remained the gold standard for treatment, with extended endoscopic endonasal surgery emerging as a viable alternative. Historical microsurgical series do not distinguish based on tumor anatomy, but are being used as a comparison against endonasal surgery. In this study, the authors retrospectively reviewed and compared the anatomy of perisellar meningiomas seen at their institution. The tumors were separated into 2 groups based on whether they would be appropriate for endoscopic resection, and the authors compared the surgical outcomes.

METHODS

Between 2001 and 2013, 53 patients (73.6% women) with perisellar meningiomas underwent open microsurgical resection at Vancouver General Hospital performed by the senior author (R.A.). These tumors were separated into 2 groups based on their anatomy, and the authors analyzed the resection rates, surgical results, patient quality of life, and complications.

RESULTS

Among the 53 patients who presented with perisellar meningiomas, the authors were able to identify 18 lesions with “simple” anatomy suitable for endoscopic resection and 35 lesions with “complex” anatomy suitable for craniotomy resection. The mean age of patients in the study cohort was 57.4 years (range 33–91 years), and most patients presented with visual loss (68.0%) and visual field restriction (64.2%). There were no major differences in patient demographic data between the 2 groups. Patients with simple anatomy had smaller lesions (2.1 vs 3.5 cm; p = 0.004), no optic canal invasion (89% vs 26%; p < 0.0001), minimal vascular encasement (cortical cuff 83% vs 9%; p < 0.0001), and a rounded tumor shape (100% vs 31.8%; p = 0.0001) when compared with those with complex anatomy. The majority of lesions originated from the tuberculum sellae and planum sphenoidale. A greater degree of resection was achieved in the favorable anatomy group (99% vs 87.1%; p < 0.0001). Vision was improved or normalized in 96.6% of patients. Patients in the cohort with complex anatomy had more transient complications; there were no incidents of surgical-site infection, meningitis, or death in this series. One patient who underwent removal of a recurrent lesion experienced a CSF leak that required endoscopic repair. The overall persisting complications rate was higher in the group with complex anatomy (11.1% vs 37.1%; p = 0.0498); overall, 28.3% of patients experienced disabling complications. Patient-perceived quality of life improved in the simple anatomy group following surgery (ΔSF-36 +16.6 vs −8.4; p = 0.0045).

CONCLUSIONS

Extended endoscopic surgery is emerging as a viable alternative to microsurgical resection of perisellar meningiomas. The authors identified 2 patient groups based on tumor anatomy, with distinctly separate surgical outcomes. In the future, patients considered for endoscopic resection should be compared against the surgical group with simple anatomy that includes smaller tumors, no vascular encasement, and limited optic canal invasion.

Ipsilateral Motor Innervation Discovered Incidentally on Intraoperative Monitoring: A Case Report

BACKGROUND AND IMPORTANCE: Lesions in the corticospinal tract above the decussation at the medullary pyramids almost universally produce contralateral deficits. Rare cases of supratentorial lesions causing ipsilateral motor deficits have been reported previously, but only ever found secondary to stroke or congenital pyramidal tract malformations.

CLINICAL PRESENTATION: Herein, we report a case of ipsilateral corticospinal tract innervation discovered incidentally with intraoperative monitoring during a microsurgical resection of a vestibular schwannoma. Intraoperative monitoring with electrical transcranial stimulation of the frontal scalp triggered motor-evoked potentials in the ipsilateral arms. The uncrossed pathways were later confirmed with MRI tractography using diffusion tensor imaging.

CONCLUSION: To the best of our knowledge, this is the first case of isolated ipsilateral motor innervation of the corticospinal tract discovered incidentally during a neurosurgical procedure. Given the increasing use of intraoperative monitoring, this case underscores the importance of cautious interpretation of seemingly discordant neurophysiological findings. Once technical issues have been ruled out, ipsilateral motor innervation may be considered as a possible explanation and neurosurgeons should be aware of the existence of this rare anatomic variant.

Use of Tranexamic Acid Is Associated with Reduced Blood Product Transfusion in Complex Skull Base Neurosurgical Procedures: A Retrospective Cohort Study

BACKGROUND

Compared with other procedures, complex skull base neurosurgery has the potential for increased intraoperative blood loss yet coagulation near eloquent cranial structures should be minimized. The safety and efficacy of the antifibrinolytic, tranexamic acid in elective neurosurgical procedures is not known. Our primary objective was to determine the relationship between the use of tranexamic acid and transfusion at our institution. Our secondary objective was to determine the incidence of adverse events associated with the use of tranexamic acid.

METHODS

In this retrospective cohort study, we included all patients who underwent complex skull base neurosurgical procedures at our institution between 2001 and 2013. Tranexamic acid was introduced during these procedures in 2006. Patient and surgical variables, transfusion data, and adverse events in the perioperative period were abstracted from the medical record. The rates of transfusion and adverse events were compared between patients who did and did not receive tranexamic acid. Multivariate regression was used to identify independent predictors of perioperative transfusion.

RESULTS

We compared 245 patients who received tranexamic acid with 274 patients who did not receive the drug during the study period. The 2 groups were similar, with the exception that patients who received tranexamic acid had larger tumors (mean, 3.5 vs 2.9 cm; P < 0.001) and longer procedures (mean, 7.2 vs 6.2 hours, P < 0.001). The rate of perioperative transfusion in patients who received tranexamic acid was lower (7% vs 13%, P = 0.04). After adjusting for preoperative hemoglobin, tumor diameter, and surgical procedure category, the use of tranexamic acid was independently predictive of perioperative transfusion (adjusted odds ratio, 0.32; 95% confidence interval, 0.15-0.65, P = 0.002). The rates of thromboembolic events and seizure were similar between the 2 groups.

CONCLUSIONS

Our results demonstrate that tranexamic acid use is associated with reduced transfusion rates in our study population, with no apparent increase in seizure or thrombotic complications. Our data support the need for further randomized clinical trials to evaluate the efficacy and safety of tranexamic acid on perioperative blood loss during complex skull base neurosurgery.

Clinical and Radiographic Factors Predicting Hearing Preservation Rates in Large Vestibular Schwannomas

Objectives Postoperative hearing preservation rates for patients with large vestibular schwannomas range from 0 to 43%. The clinical and radiographic factors predicting hearing preservation in smaller vestibular schwannomas are well described; however, their importance in larger tumors is unclear. We investigated factors predicting hearing preservation in large vestibular schwannomas. Design Retrospective review. Setting Quaternary care academic center. Participants A total of 85 patients with unilateral vestibular schwannomas > 3 cm underwent retrosigmoid resections. Main Outcomes Measures Preoperative and postoperative serviceable hearing rates. Methods Clinical and radiographic data including preoperative and postoperative audiograms, preoperative symptoms, magnetic resonance imaging features, and postoperative facial weakness were analyzed. Results Hearing was preserved in 41% of patients (17 of 42) with preoperative serviceable hearing. Hypertension and diabetes increased the likelihood of preoperative hearing loss. Preoperative tinnitus predicted a lower likelihood of hearing preservation. No radiographic factors predicted hearing preservation; however, larger tumor size, smaller fourth ventricular width, and the presence of a cerebrospinal fluid cleft surrounding the tumor predicted postoperative facial weakness. Conclusion Systemic comorbidities may influence hearing loss preoperatively in patients with large vestibular schwannomas. The absence of tinnitus may reflect hearing reserve and propensity for hearing preservation. Preoperative radiographic features did not predict hearing preservation despite some associations with postoperative facial weakness.

Stereotactic Radiosurgery versus Natural History in Patients with Growing Vestibular Schwannomas

Objective To describe our experience with stereotactic radiosurgery and its efficacy on growing tumors, and then to compare this result with the natural history of a similar cohort of non-radiation-treated lesions. Study Design A retrospective chart review and cohort comparison. Methods The long-term control rates of patients having undergone radiosurgery were collected and calculated, and this population was then compared with a group of untreated patients from the same period of time with growing lesions. Results A total of 61 patients with growing vestibular schwannomas treated with radiosurgery were included. After a mean of 160 months, we observed a control rate of 85.2%. When compared with a group of 36 patients with growing tumors who were yet to receive treatment (previously published), we found a corrected control rate or relative risk reduction of only 76.8%. Conclusion Radiosurgery for growing vestibular schwannomas is less effective than previously reported in unselected series. Although radiosurgery still has a role in managing this disease, consideration should be given to the actual efficacy that may be calculated when the natural history is known. We hope other centers will similarly report their experience on this cohort of patients.

Lack of Association between Human Herpesvirus and Vestibular Schwannoma

Objective

To assess for the presence of human herpesvirus (HHV) using immunohistochemical and polymerase chain reaction (PCR) assay in surgically excised vestibular schwannoma (VS) samples.

Study Design

Cross-sectional study.

Setting

A retrospective laboratory-based study of tumors from patients with vestibular schwannoma.

Subjects and Methods

Tissue microarrays (TMAs) representing sporadic and NF2-associated VS from 121 patients, as well as appropriate positive and negative controls, were studied. TMA sections were immunostained using antibodies directed against HHV-1, HHV-2, HHV-3, HHV-4, HHV-5, and HHV-8. PCR was used for the detection of all 8 known human herpesviruses.

Results

There was no detectable HHV (HHV-1, HHV-2, HHV-3, HHV-4, HHV-5, HHV-8) by immunohistochemistry in any of the 121 cases of sporadic and NF2 cases analyzed. These data were further validated by DNA sequence analyses using PCR in a subset of the VS samples, all of which were found to be negative for all HHV.

Conclusions

The data offer no support for an association between HHV and the development of sporadic or NF2-associated VS in humans.

Long-term outcomes of fractionated stereotactic radiation therapy for pituitary adenomas at the BC Cancer Agency

PURPOSE

To assess the long-term disease control and toxicity outcomes of fractionated stereotactic radiation therapy (FSRT) in patients with pituitary adenomas treated at the BC Cancer Agency.

METHODS AND MATERIALS

To ensure a minimum of 5 years of clinical follow-up, this study identified a cohort of 76 patients treated consecutively with FSRT between 1998 and 2007 for pituitary adenomas: 71% (54/76) had nonfunctioning and 29% (22/76) had functioning adenomas (15 adrenocorticotrophic hormone-secreting, 5 growth hormone-secreting, and 2 prolactin-secreting). Surgery was used before FSRT in 96% (73/76) of patients. A median isocenter dose of 50.4 Gy was delivered in 28 fractions, with 100% of the planning target volume covered by the 90% isodose. Patients were followed up clinically by endocrinologists, ophthalmologists, and radiation oncologists. Serial magnetic resonance imaging was used to assess tumor response.

RESULTS

With a median follow-up time of 6.8 years (range, 0.6 - 13.1 years), the 7-year progression-free survival was 97.1% and disease-specific survival was 100%. Of the 2 patients with tumor progression, both had disease control after salvage surgery. Of the 22 patients with functioning adenomas, 50% (11/22) had complete and 9% (2/22) had partial responses after FSRT. Of the patients with normal pituitary function at baseline, 48% (14/29) experienced 1 or more hormone deficiencies after FSRT. Although 79% (60/76) of optic chiasms were at least partially within the planning target volumes, no patient experienced radiation-induced optic neuropathy. No patient experienced radionecrosis. No secondary malignancy occurred during follow-up.

CONCLUSION

In this study of long-term follow-up of patients treated for pituitary adenomas, FSRT was safe and effective.

Hearing preservation after microsurgical resection of large vestibular schwannomas

BACKGROUND

Hearing, which is often still clinically useful at presentation even with larger tumors, is a major determinant of quality of life in vestibular schwannoma (VS) patients.

OBJECTIVE

To present the hearing preservation rate after surgery in patients with large (>or=3 cm) VSs and identify clinical or radiologic predictors of hearing preservation.

METHODS

From April 2003 to March 2009, 192 patients underwent resection of a VS, including 46 large (>or=3 cm) tumors, of whom 28 had serviceable hearing preoperatively. Six of 28 patients (21.4%) had preserved hearing postoperatively.

RESULTS

Mean tumor diameter was 3.6 cm (range, 3.0-5.0 cm) and tumor volume was 17.2 mL (range, 6.9-45.2 mL). For patients with grade A Sanna-Fukushima hearing, the hearing preservation rate was 4 of 11 (36.4%). Complete resection was achieved in 6 of 6 cases with hearing preservation (41/47 for all patients). Six of 6 patients with preserved hearing had a cerebrospinal fluid cleft in the internal auditory canal (IAC) compared with 9 of 16 patients without preoperative hearing and 9 of 20 for patients with serviceable hearing that was lost postoperatively (P=.045). Six of 6 patients with preserved hearing had less than 35% of the tumor anterior to the longitudinal axis of the IAC compared with 13 of 20 in the serviceable hearing that was lost group (P=.036).

CONCLUSION

Our series demonstrates hearing preservation is possible for patients with large VSs and should be attempted in all patients with preoperative hearing. The quality of preoperative hearing, a cerebrospinal fluid cleft at the apex of the IAC, and a smaller proportion of tumor anterior to the IAC were positively associated with hearing preservation.

ICA Occlusion by an ACTH-secreting pituitary adenoma post-TSS and irradiation

Occlusion of intracranial arteries by a pituitary adenoma with ensuing infarction is a rare occurrence. In this case study, we show the instance of a pituitary macroadenoma and apoplexy causing mechanical obstruction of the internal carotid artery with consequent infarction following transphenoidal surgery (TSS) and radiation therapy in a patient with Cushing's disease. We report a 44-year-old woman presented with amenorrhea and headaches. Necessary investigations, resection by TSS, and microscopic examination revealed an adenocorticotropin (ACTH)-secreting pituitary macroadenoma. The pituitary tumour recurred in subsequent years, resulting in the development of Cushing's disease and syndrome. Despite two more transphenoidal surgeries, radiotherapy, and medical suppressive therapy, the pituitary adenoma continued to enlarge, and the hypercortisolemia and Cushingoid symptoms persisted. A craniotomy was arranged as the next step in the treatment strategy. Only hours prior to the scheduled surgery, the patient developed left-sided hemiplegia, was diagnosed with acute occlusion of the right ICA and underwent an emergency bifrontal craniotomy with evacuation of the tumour and decompression. Pathological examination revealed evidence of apoplexy in the ACTH-secreting pituitary adenoma. This case demonstrates the vast scope of complications that can arise from pituitary adenomas despite combination therapy and forewarns clinicians to be prepared to manage these infrequent but conceivable occurrences.

An incidence of anteroinferior cerebellar artery/posteroinferior cerebellar artery anatomic variants penetrating the subarcuate fossa dura: operative technique and identification with 3-dimensional fast imaging employing steady-state acquisition magnetic resonance imaging

OBJECTIVE

This case series reports an incidence of anomalous vascular anatomy within the cerebellopontine angle. The relevant literature effectively describes techniques for mobilization yet underestimates the incidence. There has been no literature on the use of magnetic resonance imaging (MRI) to preoperatively identify this anatomic variant.

METHODS

We identify 8 cases of anomalous vascular anatomy within the cerebellopontine angle over a period of 6 years. They were uniformly identified through a retrosigmoid approach. Retrospective review of available 3-dimensional fast imaging employing steady-state acquisition (3D-FIESTA) sequences was performed. Intraoperative video capture of technique for mobilization was obtained. Institutional neurosurgical database review identified retrosigmoid craniotomies performed by the senior surgeon.

RESULTS

We identify 8 of 192 cases (4.2%) as having this anomalous vascular anatomy. This aberrant vascular loop resulted in subtotal resection in 3 of 8 cases (37.5%) and significant morbidity in 1 of 8 cases (12.5%). The retrospective review of the 3D-FIESTA MRI sequences positively identified this aberrant vascular course in 5 of 5 cases (100%). The digital video recording is of high quality and demonstrates proper technique for mobilization.

CONCLUSION

The presence of this vessel creates the potential for technical difficulty and significant complications. We report the incidence and techniques of mobilization. This variant can potentially be identified on preoperative 3D-FIESTA MRI sequences. Knowledge of this anatomy may guide neurosurgeons in their case preparation.

Prospective comparison of quality of life before and after observation, radiation, or surgery for vestibular schwannomas

OBJECT

The best management strategy for small-to medium-sized vestibular schwannomas (VSs) remains controversial between observation, radiation, and microsurgical resection (surgery). The authors undertook a prospective observational cohort study comparing all 3 therapeutic modalities in patients with VSs, focusing on quality of life (QOL) outcomes.

METHODS

All patients in the study completed the 36-Item Short Form Health Survey at regular intervals, with a mean follow-up of 31.8 months. Two hundred five (77.7%) of 264 patients completed questionnaires, including 47 who underwent observation, 48 who received either linear accelerator radiosurgery or fractionated radiotherapy (radiation group), and 134 who underwent surgery (of whom 37 had tumors > 3 cm in diameter). Patients allocated to the observation group had smaller tumors than those in the other groups (mean 1.3 cm; p < 0.001). Patients who received radiation were older than patients in the other groups (mean 60.0 years; p < 0.001).

RESULTS

There were no baseline QOL differences between the observation, radiation, and surgery (tumors <or= 3 cm) groups. Quality of life remained unchanged for the observation and radiation groups throughout the follow-up period. In the surgery group with tumors <or= 3 cm, a significant improvement in total score and composite mental dimension was observed at 24 months. In the surgery group with tumors > 3 cm, there was an early improvement in composite mental dimension at 1.5 months, as well as at 24 months; total score and composite physical dimension were improved at 24 months in this group as well.

CONCLUSIONS

Based on the current management protocol, patients with VSs enjoy similar QOL throughout the follow-up period after undergoing observation, radiation therapy, or surgery.