Dose-Escalated Radiation Therapy Is Associated With Improved Outcomes for High-Grade Meningioma

PURPOSE

The optimal modern radiation therapy (RT) approach after surgery for atypical and malignant meningioma is unclear. We present results of dose escalation in a single-institution cohort spanning 2000 to 2021.

METHODS AND MATERIALS

Consecutive patients with histopathologic grade 2 or 3 meningioma treated with RT were reviewed. A dose-escalation cohort (≥66 Gy equivalent dose in 2-Gy fractions using an α/β = 10) was compared with a standard-dose cohort (<66 Gy). Outcomes were progression-free survival (PFS), cause-specific survival, overall survival (OS), local failure (LF), and radiation necrosis.

RESULTS

One hundred eighteen patients (111 grade 2, 94.1%) were identified; 54 (45.8%) received dose escalation and 64 (54.2%) standard dose. Median follow-up was 45.4 months (IQR, 24.0-80.0 months) and median OS was 9.7 years (Q1: 4.6 years, Q3: not reached). All dose-escalated patients had residual disease versus 65.6% in the standard-dose cohort (P < .001). PFS at 3, 4, and 5 years in the dose-escalated versus standard-dose cohort was 78.9%, 72.2%, and 64.6% versus 57.2%, 49.1%, and 40.8%, respectively, (P = .030). On multivariable analysis, dose escalation (hazard ratio [HR], 0.544; P = .042) was associated with improved PFS, whereas ≥2 surgeries (HR, 1.989; P = .035) and older age (HR, 1.035; P < .001) were associated with worse PFS. The cumulative risk of LF was reduced with dose escalation (P = .016). Multivariable analysis confirmed that dose escalation was protective for LF (HR, 0.483; P = .019), whereas ≥2 surgeries before RT predicted for LF (HR, 2.145; P = .008). A trend was observed for improved cause-specific survival and OS in the dose-escalation cohort (P < .1). Seven patients (5.9%) developed symptomatic radiation necrosis with no significant difference between the 2 cohorts.

CONCLUSIONS

Dose-escalated RT with ≥66 Gy for high-grade meningioma is associated with improved local control and PFS with an acceptable risk of radiation necrosis.

Virtual Reality Simulation for the Middle Cranial Fossa Approach: A Validation Study

BACKGROUND AND OBJECTIVES

Virtual reality (VR) surgical rehearsal is an educational tool that exists in a safe environment. Validation is necessary to establish the educational value of this platform. The middle cranial fossa (MCF) is ideal for simulation because trainees have limited exposure to this approach and it has considerable complication risk. Our objectives were to assess the face, content, and construct validities of an MCF VR simulation, as well as the change in performance across serial simulations.

METHODS

Using high-resolution volumetric data sets of human cadavers, the authors generated a high-fidelity visual and haptic rendering of the MCF approach using CardinalSim software. Trainees from Neurosurgery and Otolaryngology-Head and Neck Surgery at two Canadian academic centers performed MCF dissections on this VR platform. Randomization was used to assess the effect of enhanced VR interaction. Likert scales were used to assess the face and content validities. Performance metrics and pre- and postsimulation test scores were evaluated. Construct validity was evaluated by examining the effect of the training level on simulation performance.

RESULTS

Twenty trainees were enrolled. Face and content validities were achieved in all domains. Construct validity, however, was not demonstrated. Postsimulation test scores were significantly higher than presimulation test scores ( P < .001 ). Trainees demonstrated statistically significant improvement in the time to complete dissections ( P < .001 ), internal auditory canal skeletonization ( P < .001 ), completeness of the anterior petrosectomy ( P < .001 ), and reduced number of injuries to critical structures ( P = .001 ).

CONCLUSION

This MCF VR simulation created using CardinalSim demonstrated face and content validities. Construct validity was not established because no trainee included in the study had previous MCF approach experience, which further emphasizes the importance of simulation. When used as a formative educational adjunct in both Neurosurgery and Otolaryngology-Head and Neck Surgery, this simulation has the potential to enhance understanding of the complex anatomic relationships of critical neurovascular structures.

Delayed neurological improvement in a patient with Duret hemorrhage secondary to an acute subdural hematoma: illustrative case

BACKGROUND

Duret hemorrhage is a rare phenomenon wherein rapid transtentorial herniation results in brainstem injury and hemorrhage. It is usually regarded as a poor prognostic factor representing irreversible and often catastrophic brain injury. The authors report an unusual case of Duret hemorrhage with spontaneous delayed neurological recovery postoperatively after surgical treatment of an acute subdural hematoma (SDH).

OBSERVATIONS

The authors present the case of a 65-year-old male who initially presented to the hospital with a large acute left-sided SDH causing 1.3 cm of midline shift. He was taken urgently for a craniotomy, with no significant intraoperative swelling or visible contusions. Postoperative imaging revealed an unexpected pontine hyperdensity concerning for a Duret hemorrhage. He initially had no neurological improvement; however, at 3 weeks postoperatively, he gradually recovered and was able to follow commands and was extubated. At 10 weeks after surgery, his Glasgow Coma Scale score improved to 15, with mild residual left hemiparesis.

LESSONS

This case challenges a classic dogma that Duret hemorrhage carries a universally poor outcome. In select cases, patients can make meaningful recoveries in a delayed fashion. The lack of intraoperative contusions and swelling may have contributed to this patient's recovery.

Outcomes Following Dose Escalated Radiotherapy for High Grade Meningioma

PURPOSE/OBJECTIVE(S)

Conventionally fractionated radiotherapy (RT) is a defined treatment following surgery for atypical and malignant meningioma. However, the optimal radiotherapeutic approach is not well defined. We present the results of our dose-escalation strategy.

MATERIALS/METHODS

Consecutive patients with a histopathologic grade 2 or 3 meningioma treated with RT were retrospectively reviewed. The primary outcome was progression-free survival (PFS), and secondary outcomes included cause-specific survival (CSS), overall survival (OS), local failure and incidence of radiation necrosis. We specifically compared the dose-escalation cohort, defined as those treated with ≥66 Gy EQD2 (equivalent dose in 2 Gy fractions, a/b = 10), to the standard dose cohort receiving <66 Gy EQD2. We defined adjuvant as RT delivered within 6 months of surgery otherwise the treatment was salvage.

RESULTS

A total of 118 patients with Grade 2 (111/118) or 3 (7/118) meningioma were identified. 54/118 (45.8%) received dose-escalation and 64/118 (54.2%) standard dosing. 34/54 (63.0%) dose-escalated and 45/64 (70.3%) standardly dosed were treated adjuvantly. The median follow-up was 45.4 months (IQR: 24.0-80.0 months) and median OS was 9.7 years. Post-operative residual disease was present in all dose-escalated patients, as compared to 65.6% in the standard dose cohort. PFS at 3-, 4- and 5-years in the dose-escalated vs. standard dose cohort were 78.9%, 72.2% and 64.6% vs. 57.2%, 49.1% and 40.8%, respectively, (p = 0.030). On multivariable (MVA) analysis, dose-escalation (HR: 0.544, 95% CI: 0.303-0.977, p = 0.042) was associated with improved PFS, whereas ≥2 surgeries (HR: 1.989, 95% CI: 1.049-3.773, p = 0.035) and older age (HR: 1.035, 95% CI:1.015-1.056, p<0.001) associated with worse PFS. The cumulative risk of local failure at 3-, 4- and 5-years in the dose-escalated vs. standard dose cohort were 16.9%, 23.8% and 31.8% vs. 39.6%, 45.6% and 53.9%, respectively, favoring dose-escalation (p = 0.016). MVA confirmed dose-escalation as predictive of a lower risk of LF (HR: 0.483, 95% CI: 0.263-0.887, p = 0.019), while ≥2 surgeries prior to RT predicted for greater LF rates (HR:2.145, 95% CI:1.220-3.771, p = 0.008). A trend was observed for prolonged CSS and OS in the dose escalation cohort (p = <0.1). Seven patients (5.9%) developed symptomatic radiation necrosis (RN) with no significant difference between the two cohorts.

CONCLUSION

Dose-escalated radiotherapy for high grade meningioma to at least 66 Gy is associated with significantly improved rates of local control and PFS with an acceptable risk of RN.

Malignant Cerebellopontine Angle Peripheral Nerve Sheath Tumor with Divergent Mesenchymal (Cartilaginous) Differentiation Presenting with Catastrophic Hemorrhage: Case Report and Review

Malignant peripheral nerve sheath tumors of the cerebellopontine angle are rare, especially even outside of the context of neurofibromatosis or malignant transformation of previously radiated vestibular schwannomas. This case report describes a case of a presumed vestibular schwannoma without previous radiation or history of neurofibromatosis presenting with progressive hearing loss, facial weakness, growth, and ultimately catastrophic hemorrhage requiring urgent surgery. Histopathology revealed an exceptionally rare malignant peripheral nerve sheath tumor with divergent mesenchymal (chondrosarcomatous) differentiation with few rigorously interrogated cases in the literature. In retrospect, facial weakness, growth, and early intratumoral hemorrhage were harbingers of atypical malignant pathology. We advocate for a heightened index of suspicion, shorter interval follow-up, and consideration of early surgery in such cases in hopes of preventing potentially catastrophic outcomes.

Pre-Injury Antiplatelet Therapy and Risk of Adverse Outcomes after Traumatic Brain Injury: A Systematic Review and Meta-Analysis

There is an increasing number of trauma patients presenting on pre-injury antiplatelet (AP) agents attributable to an aging population and expanding cardio- or cerebrovascular indications for antithrombotic therapy. The effects of different AP regimens on outcomes after traumatic brain injury (TBI) have yet to be elucidated, despite the implications on patient/family counseling and the potential need for better reversal strategies. The goal of this systematic review and meta-analysis was to assess the impact of different pre-injury AP regimens on outcomes after TBI. In accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, the OVID Medline, Embase, BIOSIS, Scopus, and Cochrane databases were searched from inception to February 2022 using a combination of terms pertaining to TBI and use of AP agents. Baseline demographics and study characteristics as well as outcome data pertaining to intracerebral hematoma (ICH) progression, need for neurosurgical intervention, hospital length of stay, mortality, and functional outcome were extracted. Pooled odds ratios (ORs) and mean differences comparing groups were calculated using random-effects models. Thirteen observational studies, totaling 1244 patients receiving single AP therapy with acetylsalicylic acid or clopidogrel, 413 patients on dual AP therapy, and 3027 non-AP users were included. No randomized controlled trials were identified. There were significant associations between dual AP use and ICH progression (OR, 2.81; 95% confidence interval [CI], 1.19–6.61; I², 85%; p = 0.02) and need for neurosurgical intervention post-TBI (OR, 1.61; 95% CI, 1.15–2.28; I², 15%; p = 0.006) compared to non-users, but not between single AP therapy and non-users. There were no associations between AP use and hospital length of stay or mortality after trauma. Pre-injury dual AP use, but not single AP use, is associated with higher rates of ICH progression and neurosurgical intervention post-TBI. However, the overall quality of studies was low, and this association should be further investigated in larger studies.

A phase II pilot randomized controlled trial to assess the feasibility of the "supra-marginal" surgical resection of malignant glioma (G-SUMIT: Glioma supra marginal incision trial) study protocol

Background

High-grade gliomas are the most common primary malignant brain tumor in adults having a median survival of only 13–16 months. This is despite the current standard of maximal safe surgical resection followed by fractionated radiotherapy and chemotherapy. Extending the tumor resection limit beyond the gadolinium (GAD)-enhancing margin (i.e., supra-marginal resection) could in principle provide an added survival benefit as it has been shown that > 80% of post-operative tumor recurrence is within a 2-cm region surrounding the original GAD-enhancing margin. However, this must be weighed against the risk of potential damage to functional brain tissue.

Methods

In this phase II pilot randomized control trial (RCT), we aim to assess the feasibility of “supra-marginal” resection extending 1 cm beyond the enhancing tumor in adults with radiographic evidence of GAD-enhancing intra-axial tumor consistent with high-grade glioma in a safe anatomical location and a Karnofsky Performance Score > 60. With six academic institutions with established neurosurgical oncology practices in participation, we aim to enroll 72 patients over 2 years. Primary outcomes include evaluating the feasibility of performing a large-scale trial with regard to recruitment, allocation, and outcome documentation as well as safety data. Secondary outcomes include determining if there is an increased survival benefit with supra-marginal resection and impact on quality of life (Modified Rankin Scale (mRS), EuroQol-5D (ED-5D), 30-day all-cause mortality).

Discussion

Recent studies have revealed survival advantages comparing supra-marginal resection to standard attempt at gross total resection (GTR) with no additional perioperative surgical risk; however, the current quality of evidence is low and under-powered. Therefore, there are no current practice guidelines, and the philosophy of surgical resection is guided by individual surgeon preferences on an individual patient basis. This creates additional uncertainty and is potentially detrimental to our patients. This clinical equipoise supports the need for an adequately powered RCT to determine whether a supra-marginal resection can have a positive impact on survival for patients with HGGs. Our pilot RCT will test the feasibility of comparing the standard gross total resection of GAD-enhancing tumors and supra-marginal resection to prepare for a larger definitive multicenter RCT.

Trial registration

ClinicalTrials.gov, NCT04737577. Registered on February 4, 2021

Supplementary Information

The online version contains supplementary material available at 10.1186/s40814-022-01104-1.

IOTG-02. Glioma Supra Marginal Incision Trial (G-SUMIT): a phase II pilot randomized control trial to assess the feasibility of “supra-marginal” surgical resection of malignant glioma

High grade gliomas are the most common primary malignant brain tumor in adults having a median survival of only 13–16 months. This is despite the current standard of maximal safe surgical resection followed by fractionated radiotherapy and chemotherapy. Extending the tumor resection limit beyond the GAD-enhancing margin (i.e. supra-marginal resection) could in principle provide an added survival benefit as it has been shown that &gt;80% of post-operative tumor recurrence is within a 2cm region surrounding the original GAD-enhancing margin. However, this must be weighed against the risk of potential damage to functional brain tissue. In this phase II pilot randomized control trial (RCT), we aim to assess the feasibility of “supra-marginal” resection extending 1cm beyond the enhancing tumor in adults with radiographic evidence of GAD-enhancing intra-axial tumour consistent with high grade glioma in a safe anatomical location and a Karnofsky Performance Score &gt; 60. With six academic centres participating, we aim to enroll 72 patients over two years. Currently, four patients have already been enrolled in the first four months. Primary outcomes include evaluating the feasibility of performing a large-scale trial with regards to recruitment, allocation and outcome documentation as well as safety data. Secondary outcomes include determining if there is an increased survival benefit with supra-marginal resection and impact on quality of life. Our pilot RCT will test the feasibility of comparing standard gross total resection of GAD-enhancing tumour and supra-marginal resection to prepare for a larger definitive multicentre RCT.

Development and validation of a patient-centered, meningioma-specific quality-of-life questionnaire

OBJECTIVE

Meningiomas can have significant impact on health-related quality of life (HRQOL). Patient-centered, disease-specific instruments for assessing HRQOL in these patients are lacking. To this end, the authors sought to develop and validate a meningioma-specific HRQOL questionnaire through a standardized, patient-centered questionnaire development methodology.

METHODS

The development of the questionnaire involved three main phases: item generation, item reduction, and validation. Item generation consisted of semistructured interviews with patients (n = 30), informal caregivers (n = 12), and healthcare providers (n = 8) to create a preliminary list of items. Item reduction with 60 patients was guided by the clinical impact method, multiple correspondence analysis, and hierarchical cluster analysis. The validation phase involved 162 patients and collected evidence on extreme-groups validity; concurrent validity with the SF-36, FACT-Br, and EQ-5D; and test-retest reliability. The questionnaire takes on average 11 minutes to complete.

RESULTS

The meningioma-specific quality-of-life questionnaire (MQOL) consists of 70 items representing 9 domains. Cronbach's alpha for each domain ranged from 0.61 to 0.91. Concurrent validity testing demonstrated construct validity, while extreme-groups testing (p = 1.45E-11) confirmed the MQOL's ability to distinguish between different groups of patients.

CONCLUSIONS

The MQOL is a validated, reliable, and feasible questionnaire designed specifically for evaluating QOL in meningioma patients. This disease-specific questionnaire will be fundamentally helpful in better understanding and capturing HRQOL in the meningioma patient population and can be used in both clinical and research settings.

Management of Diffuse Low-Grade Glioma: The Renaissance of Robust Evidence

The surgical management of diffuse low-grade gliomas (DLGGs) has undergone a paradigm shift toward striving for maximal safe resection when feasible. While extensive observational data supports this transition, unbiased evidence in the form of high quality randomized-controlled trials (RCTs) is lacking. Furthermore, despite a high volume of molecular, genetic, and imaging data, the field of neuro-oncology lacks personalized care algorithms for individuals with DLGGs based on a robust foundation of evidence. In this manuscript, we (1) discuss the logistical and philosophical challenges hindering the development of surgical RCTs for DLGGs, (2) highlight the potential impact of well-designed international prospective observational registries, (3) discuss ways in which cutting-edge computational techniques can be harnessed to generate maximal insight from high volumes of multi-faceted data, and (4) outline a comprehensive plan of action that will enable a multi-disciplinary approach to future DLGG management, integrating advances in clinical medicine, basic molecular research and large-scale data mining.

Reinitiation of Anticoagulation After Surgical Evacuation of Subdural Hematomas

BACKGROUND

Chronic subdural hematoma (cSDH) is an increasingly common condition due to the growing use of anticoagulation. Currently, there remains a lack of evidence to guide the optimal timing of anticoagulant reinitiation for stroke prevention in atrial fibrillation after cSDH evacuation. We aimed to better understand the perceived risks of hemorrhagic and embolic complications along with current practice patterns on restarting anticoagulation after surgical evacuation of cSDH.

METHODS

We conducted a survey of Canadian neurosurgeons and stroke neurologists using a novel self-administered questionnaire using clinical cases that included questions on clinical experience, practice setting, practice patterns, and perceptions on stroke/bleeding risk with anticoagulation reinitiation after cSDH evacuation. The instrument was evaluated for clinical sensibility by 5 neurosurgeons, neurologists, and intensivists.

RESULTS

The response rate after 4 mailings was 40% for neurosurgeons (55/136) and 21% for stroke neurologists (26/122). Almost all participants would restart anticoagulation for stroke prevention in atrial fibrillation after cSDH evacuation (91.8% in low-risk patients, 98.6% in high-risk patients). Time to reinitiation of anticoagulation varied considerably, particularly for high-risk patients where 36% of participants would restart anticoagulation within 1 week of surgery, 44% between 1 and 4 weeks after surgery, and 19% after 4 weeks postoperatively. The perceived risk of stroke and SDH reaccumulation varied considerably among participants and was dependent on timing of anticoagulation reinitiation.

CONCLUSIONS

There is considerable variation in current practice patterns and perceived risks of embolic and hemorrhagic complications with anticoagulation reinitiation after cSDH evacuation. These results demonstrate clinical equipoise that warrant further targeted investigation in large-scale randomized controlled trials.

Novel Statistical Analyses to Assess Hearing Outcomes After ABI Implantation in NF2 Patients: Systematic Review and Individualized Patient Data Analysis

BACKGROUND

Patients with neurofibromatosis type 2 develop bilateral vestibular schwannomas with progressive hearing loss. Auditory brainstem implants (ABIs) stimulate hearing in the cochlear nuclei and show promise in improving hearing. Here, we assess the impact of ABI on hearing over time by systematically reviewing the literature and re-analyzing available individual patient data.

METHODS

A multidatabase search identified 3 studies with individual patient data of longitudinal hearing outcomes after ABI insertion in adults. Data were collected on hearing outcomes of different sound complexities from sound to speech using an ABI ± lip reading ability plus demographic data. Because of heterogeneity each study was analyzed separately using random effects multilevel mixed linear modeling.

RESULTS

Across all 3 studies (n = 111 total) there were significant improvements in hearing over time from ABI placement (P < 0.000 in all). Improvements in comprehension of sounds, words, sentences, and speech occurred over time with ABI use + lip reading but lip reading ability did not improve over time. All categories of hearing complexity had over 50% comprehension after over 1 year of ABI use and some subsets had over 75% or near 100% comprehension. Vowel comprehension was greater than consonant, and word comprehension was greater than sentence comprehension (P < 0.0001 in both). Age and sex did not predict outcomes.

CONCLUSIONS

ABIs improve hearing beyond lip reading alone, which represents baseline patient function prior to treatment, and the benefits continue to improve with time. These findings may be used to guide patient counseling regarding ABI insertion, rehabilitation course after insertion, and future studies.

Anticoagulant prophylaxis against venous thromboembolism following severe traumatic brain injury: A prospective observational study and systematic review of the literature

OBJECTIVES

Venous thromboembolism (VTE) is a serious complication following severe traumatic brain injury (TBI), however, anticoagulant prophylaxis remains controversial due to concerns of intracranial hemorrhage (ICH) progression. We examined anticoagulant prophylaxis practice patterns at a major trauma centre and determined risk estimates for VTE and ICH progression classified by timing of anticoagulant initiation.

PATIENTS AND METHODS

A 1-year prospective analysis of consecutive patients with severe TBI admitted to a Level-I trauma centre was conducted. In addition, we systematically reviewed the literature to identify studies on VTE and anticoagulant prophylaxis after severe TBI.

RESULTS

64 severe TBI patients were included. 83% of patients received anticoagulant prophylaxis, initiated ≥3d post-TBI in 67%. The in-hospital VTE incidence was 16% and there was no significant difference between patients who received early (<3d) versus late (≥3d) prophylaxis (10% vs. 16%). Rates of ICH progression (0% vs. 7%) were similar between groups. Our systematic review identified 5 studies with VTE rates ranging from 5 to 10% with prophylaxis, to 11-30% without prophylaxis. The effect of timing of anticoagulant prophylaxis initiation on ICH progression was not reported in any study.

CONCLUSION

VTE is a common complication after severe TBI. Anticoagulant prophylaxis is often started late (≥3d) post-injury. Randomized trials are justifiable and necessary to provide practice guidance with regards to optimal timing of anticoagulant prophylaxis.

Citation classics in neuro-oncology: assessment of historical trends and scientific progress

Background

Citation classics represent the highest cited works in a field and are often regarded as the most influential literature. Analyzing thematic trends in citation classics across eras enables recognition of important historical advances within a field. We present the first analysis of the citation classics in neuro-oncology.

Methods

The Web of Science database was searched using terms relevant to "neuro-oncology." Articles with >400 citations were identified and the top 100 cited articles were evaluated.

Results

The top 100 neuro-oncology citation classics consisted of 43 clinical studies (17 retrospective, 10 prospective, 16 randomized trials), 43 laboratory investigations, 8 reviews/meta-analyses, and 6 guidelines/consensus statements. Articles were classified into 4 themes: 13 pertained to tumor classification, 37 to tumor pathogenesis/clinical presentation, 6 to imaging, 44 to therapy (15 chemotherapy, 10 radiotherapy, 5 surgery, 14 new agents). Gliomas were the most common tumor type examined, with 70 articles. There was a significant increase in the number of citation classics in the late 1990s, which was paralleled by an increase in studies examining tumor pathogenesis, chemotherapy, and new agents along with laboratory and randomized studies.

Conclusions

The majority of citation classics in neuro-oncology are related to gliomas and pertain to tumor pathogenesis and treatment. The rise in citation classics in recent years investigating tumor biology, new treatment agents, and chemotherapeutics may reflect increasing scientific interest in nonsurgical treatments for CNS tumors and the need for fundamental investigations into disease processes.

Feasibility of real-time intraoperative fluorescence imaging of dural sinus thrombosis

Dural sinus thrombosis is a well-recognized and potentially serious complication following lateral skull base surgery. Methods of diagnosis are limited to post-operative computerized tomography scans or magnetic resonance venography. There are currently no reports of an intraoperative technique used to detect dural sinus thrombosis. Here, we describe the case of a 62-year-old woman who underwent translabyrinthine resection of a right vestibular schwannoma with no evidence of sinus thrombosis on pre-operative scans. Following tumor resection, patency of the sigmoid sinus was assessed intraoperatively using indocyanine green (ICG) videography which revealed a lack of flow in the right sigmoid sinus. Postoperative CT scan confirmed thrombosis of the right sigmoid sinus. We present the first report of real-time intraoperative diagnosis of sigmoid sinus thrombosis during removal of a vestibular schwannoma. ICG videography may be used for intraoperative visualization of dural sinus integrity and patency during prolonged or technically challenging microsurgical procedures. This technique may enable periodic monitoring and early identification of filling defects which can guide further intraoperative strategies and postoperative monitoring.

Somatosensory evoked potentials after decompressive craniectomy for traumatic brain injury

Somatosensory evoked potentials (SSEPs) are used for neuroprognosis after severe traumatic brain injury (TBI). However decompressive craniectomy (DC), involving removal of a portion of the skull to alleviate elevated intracranial pressure, is associated with an increase in SSEP amplitude. Accordingly, SSEPs are not available for neuroprognosis over the hemisphere with DC. We aim to determine the degree to which SSEP amplitudes are increased in the absence of cranial bone. This will serve as a precursor for translation to clinically prognostic ranges. Intra-operative SSEPs were performed before and after bone flap replacement in 22 patients with severe TBI. SSEP measurements were also performed in a comparison non-traumatic group undergoing craniotomy for tumor resection. N20/P25 amplitudes and central conduction time were measured with the bone flap in (BI) and out (BO). Linear regressions, adjusting for skull thickness and study arm, were performed to evaluate the contribution of bone presence to SSEP amplitudes. Latencies were not different between BO or BI trials in either group. Mean N20/P25 amplitudes recorded with BO were statistically different (p = 0.0001) from BI in both cohorts, showing an approximate doubling in BO amplitudes. For contralateral-ipsilateral montages r² was 0.28 and for frontal pole montages r² was 0.62. Cortical SSEP amplitudes are influenced by the presence of cortical bone as is particularly evident in frontal pole montages. Larger, longitudinal trials to assess feasibility of neuroprognosis over the hemisphere with DC in severe TBI patients are warranted.

Timing of Pharmacologic Venous Thromboembolism Prophylaxis in Severe Traumatic Brain Injury: A Propensity-Matched Cohort Study

BACKGROUND

Patients with severe traumatic brain injury (sTBI) are at high risk for developing venous thromboembolism (VTE). Nonetheless, pharmacologic VTE prophylaxis is often delayed out of concern for precipitating extension of intracranial hemorrhage (ICH). The purpose of this study was to compare the effectiveness of early vs late VTE prophylaxis in patients with sTBI, and to characterize the risk of subsequent ICH-related complication.

STUDY DESIGN

Adults with isolated sTBI (head Abbreviated Injury Scale score ≥3 and total Glasgow Coma Scale score ≤8) who received VTE prophylaxis with low-molecular-weight or unfractionated heparin were derived from the American College of Surgeons Trauma Quality Improvement Program (2012 to 2014). Patients were divided into EP (<72 hours) or LP (≥72 hours) groups. Propensity score matching was used to minimize selection bias. The primary end point was VTE (pulmonary embolism or deep vein thrombosis). Secondary outcomes were defined as late neurosurgical intervention (≥72 hours) or death.

RESULTS

We identified 3,634 patients with sTBI. Early prophylaxis was given in 43% of patients. Higher head injury severity, presence of ICH, and early neurosurgery were associated with late prophylaxis. Propensity score matching yielded a well-balanced cohort of 2,468 patients. Early prophylaxis was associated with lower rates of both pulmonary embolism (odds ratio = 0.48; 95% CI, 0.25-0.91) and deep vein thrombosis (odds ratio = 0.51; 95% CI, 0.36-0.72), but no increase in risk of late neurosurgical intervention or death.

CONCLUSIONS

In this observational study of patients with sTBI, early initiation of VTE prophylaxis was associated with decreased risk of pulmonary embolism and deep vein thrombosis, but no increase in risk of late neurosurgical intervention or death. Early prophylaxis may be safe and should be the goal for each patient in the context of appropriate risk stratification.

Obtuse-angled Laminotomy as a Modification of Multilevel Laminectomy for Spinal Cord Decompression

The purpose of this note is to describe an obtuse-angled laminotomy of C7 during cervical decompression that aims to preserve cervicothoracic junction stability and potentially reduce pain. Cervical spondylotic myelopathy can result from degenerative cervical spinal disease including, herniated disk material, osteophytes, redundant ligamentum flavum, or ossification of the posterior longitudinal ligament. Surgical intervention for multilevel myelopathy aims to decompress the spinal cord and maintain stability of the cervical spine. Multilevel laminectomy is traditionally used when degenerative changes affect 3 or more levels and when there is primarily dorsal compressive disease. Traditional laminectomy can result in instability and kyphosis. The C7 lamina can be particularly vulnerable given the location at cervicothoracic junction. We describe an obtuse-angled laminotomy for the most caudal lamina in a planned decompression. This lamina is left attached to ligamentum nuchea, adjacent fascia, and paravertebral muscles. Only the base of spinous process and ventral portion of lamina's cortical and cancellous bone are removed in an obtuse angle through the opening. This variation is aimed to preserve as much of the cervical stability while still achieving the goal of decompression.

A simple method for controlled reduction duraplasty during cranioplasty

BACKGROUND

Bone flap re-approximation during cranioplasty can be complicated by underlying pseudomeningocele or meningoencephalocele. A technique for controlled reduction duraplasty to aid bone flap positioning is suggested.

METHODS

A simple method using bipolar electrocautery in a predetermined radial pattern from the center of defect is described. Localized tissue contraction allows controlled reduction in the surface area and degree of protrusion. This in turn facilitates bone flap positioning.

RESULTS

The main advantage of this technique is slow and evenly distributed pressure conferred by controlled tissue contraction using multiple radial coagulation lines. No technical difficulties or complications have occurred with this method during cranioplasty for 11 patients.

CONCLUSION

This simple technique for controlled reduction duraplasty can provide an easy and efficient method for bone flap re-approximation, and add to the existing techniques for a commonly performed procedure.

Synovial Sarcoma of the Brachial Plexus

BACKGROUND AND IMPORTANCE:

Synovial sarcoma (SS) is a malignant soft-tissue tumor that rarely involves brachial plexus. The authors report a case of brachial plexus SS and review the relevant literature.

CLINICAL PRESENTATION:

A 53-year-old woman presented with gradually enlarging right subclavicular mass over 5 years associated with sharp aching pain radiating down toward the radial 3 fingers. On examination, she had a corresponding firm mass in the supraclavicular region with a positive Tinel sign. There was no objective neurological deficit. She underwent partial excision of this mass without any further adjuvant radiation or chemotherapy. Pathology was consistent with SS.

CONCLUSION:

Lack of any recurrence in this case 6 years after incomplete excision with no adjuvant therapy suggests slow clinical course in some of these sarcomas.

Aspergillosis of the Petrous Apex and Meckel's Cave

Cranial cerebral aspergillosis is a rare entity in immunocompetent patients. Invasive disease involving the petrous apex and Meckel's cave has rarely been described. We present a case of localized invasive petrous apical and Meckel's cave disease in an immunocompetent patient who presented with hemicranial neuralgic pain.

The epidemiological trends of head injury in the largest Canadian adult trauma center from 1986 to 2007

Object

This study documents the epidemiology of head injury over the course of 22 years in the largest Level I adult trauma center in Canada. This information defines the current state, changing pattern, and relative distribution of demographic factors in a defined group of trauma patients. It will aid in hypothesis generation to direct etiological research, administrative resource allocation, and preventative strategies.

Methods

Data on all the trauma patients treated at Sunnybrook Health Sciences Centre (SHSC) from 1986 to 2007 were collected in a consecutive, prospective fashion. The authors reviewed these data from the Sunnybrook Trauma Registry Database in a retrospective fashion. The aggregate data on head injury included demographic data, cause of injury, and Injury Severity Score (ISS). The collected data were analyzed using univariate techniques to depict the trend of variables over years. The authors used the length of stay (LOS) and number of deaths per year (case fatality rate) as crude measures of outcome.

Results

A total of 16,678 patients were treated through the Level I trauma center at SHSC from January 1986 to December 2007. Of these, 9315 patients met the inclusion criteria (ISS > 12, head Abbreviated Injury Scale score > 0). The median age of all trauma patients was 36 years, and 69.6% were male. The median ISS of the head-injury patients was 27. The median age of this group of patients increased by 12 years over the study period. Motorized vehicle accidents accounted for the greatest number of head injuries (60.3%) although the relative percentage decreased over the study period. The median transfer time of patients sustaining a head injury was 2.58 hours, and there was an approximately 45 minute improvement over the 22-year study period. The median LOS in our center decreased from 19 to 10 days over the study period. The average case fatality rate was 17.4% over the study period. In multivariate analysis, more severe injuries were associated with increased LOS as was increasing time from injury to hospital presentation. Age and injury severity were independently predictive of mortality.

Conclusions

These data will provide useful information to guide future studies on the changing patterns of head injury, possible mechanisms of injury, and efficient resource allocation for management of this condition.

Preoperative stereotactic body radiotherapy to a skull renal cell metastasis: an alternative to preoperative embolization?

INTRODUCTION

This is the first case study to report on using stereotactic body radiotherapy as an alternative and novel treatment modality for embolization to reduce the risk of operative bleeding for a metastatic renal cell tumor.

CASE PRESENTATION

A 58-year-old woman presented with an asymptomatic large 7-cm tumor on the parieto-occipital vertex of the skull. Given the location of this lesion along with its vascular histology, it was a challenge to provide safe and effective treatment using conventional management strategies.

CONCLUSION

We report on a rare presentation of a metastatic renal cell cancer and the use of stereotactic body radiotherapy as an innovative radiation approach to deliver high-dose radiation safely to control this large aggressive and vascular metastasis. The success of this management strategy allowed for minimal intraoperative blood loss, and the patient continues with local control 1-year posttreatment.

Epidemiological trends of spine and spinal cord injuries in the largest Canadian adult trauma center from 1986 to 2006

Object

In this study the author documents the epidemiology of spine and spinal cord injuries (SCIs) over 2 decades at the largest Level I adult trauma center in Canada. He describes the current state of spine injuries (SIs), their changing patterns over the years, and the relative distribution of different demographic factors in a defined group of trauma patients.

Methods

Data on all trauma patients admitted to Sunnybrook Health Sciences Centre between 1986 and 2006 were collected from the Sunnybrook Trauma Registry Database. Aggregate data on SIs and SCIs, including demographic information, etiology, severity of injuries (injury severity score [ISS]), and associated injuries, were recorded. The data were analyzed in a main category of spinal fracture and/or dislocation with or without SI and in two subgroups of patients with SIs, one encompassing all forms of SCIs and the other including only complete SCIs (CSCIs). Collected data were evaluated using univariate techniques to depict the trend of variables over the years. The number of deaths per year and the length of stay (LOS) were used as crude measures of outcome. Several multivariate analysis techniques, including Poisson regression, were used to model the frequency of death and LOS as functions of various trauma variables.

Results

There were 12,192 trauma patients in the study period with 23.2% having SIs, 5.4% having SCIs, and 3% having CSCIs. The SCIs constituted 23.3% of all SIs. The respective characteristics of the SI, SCI, and CSCI groups were as follows: median age 36, 33, and 30 years; median LOS 18, 27, and 29 days; median ISS 29, 30, and 34; female sex ratio 34, 24, and 23%; and case fatality rate 16.7, 16.6, and 21%. Seventy-nine percent of patients had associated head injuries; conversely, 24% of patients with head injuries had SIs. The mean admission age of patients increased by ~ 10 years over the study period, from the early 30s to the early 40s. The relative incidence of SIs remained stable at ~ 23%, but the incidence of SCIs decreased ~ 40% over time to 4.5%. Motor vehicle accidents remained the principal etiology of trauma, although falling and violence became more frequent contributors of SIs. The average annual ISS remained stable over time, but the LOS was reduced by 50% in both the SI and SCI groups. Age, ISS, and SCIs were associated with a longer LOS. The case fatality rate remained relatively unchanged over time. Poisson analysis suggested that the presence of an SCI does not change the case fatality rate.

Conclusions

Data in this analysis will provide useful information to guide future studies on changing SI patterns, possible etiologies, and efficient resource allocation for the management of these diseases.

Vascularized mastoid bone flap cranioplasty after translabyrinthine vestibular schwannoma surgery

OBJECTIVE

We describe a novel technique of cranioplasty using a vascularized mastoid bone flap in patients after translabyrinthine excision of vestibular schwannomas (VS). Postoperative outcomes in terms of pinna and postauricular deformity are evaluated.

STUDY DESIGN

Retrospective study.

SETTING

Tertiary referral center.

RESULTS

Seventeen patients underwent cranioplasty with bone flap after translabyrinthine VS excision. At minimum follow-up of 12 months, none had a cerebrospinal fluid (CSF) leak. The measured pinna projections between the operated and non-operated sides had a mean difference of 0.80 mm (+/-1.70), which is not statistically significant (p > 0.05). The mean depth of the postauricular depressions was 1.38 mm (+/-0.93). Over the same period, 10 patients underwent translabyrinthine VS surgery without cranioplasty. In this group, there was a significant difference of 4.71 mm (+/-1.53) in mean pinna underprojections on the operated sides compared with the non-operated sides. Compared with patients who have undergone cranioplasty, the retroauricular depressions were significantly deeper (p < 0.05) with a mean depth of 2.92 mm (+/-1.21).

CONCLUSIONS

Vascularized mastoid cortical bone flap cranioplasty is a simple and effective technique to ameliorate the pinna and retroauricular deformities after translabyrinthine VS excision without increased surgical cost or the use of alloplastic materials.

Neurosurgical rescue of bradycardia induced by intracerebral hypertension: a case report and review of the literature

Brain metastases usually occur secondary to lung, breast, unknown primary, melanoma, and colon cancers. A growing tumor in the brain is commonly associated with edema and increased intracranial pressure (ICP). Common signs and symptoms due to increased ICP or brain edema include headache, nausea, and vomiting. One of the main treatment modalities in the management of brain metastases is whole-brain radiation. However, increased ICP may lead to acute deterioration of the neurologic status due to development of radiation-induced edema. Therefore, alternative management options should be considered for these patients to avoid complications from whole-brain radiation treatment. We discuss the case of a brain metastases patient who presented with bradycardia induced by brain edema.

Brain Metastasis from an Unknown Primary, or Primary Brain Tumour? A Diagnostic Dilemma

Brain metastasis is increasingly common, affecting 20%–40% of cancer patients. After diagnosis, survival is usually limited to months in these patients. Treatment for brain metastasis includes whole-brain radiation therapy, surgical resection, or both. These treatments aim to slow progression of disease and to improve or maintain neurologic function and quality of life. Although less common, primary brain tumours produce symptoms that are similar to those of brain metastasis. Glioblastoma, the most common malignant tumour of the brain, has a median survival of less than 12 months. Patients are often treated with surgical resection followed by radical radiation therapy and chemotherapy. Here, we present 2 separate cases of lesions in the brain radiologically compatible with brain metastasis. In both cases, no primary cancer site had been established, and neurosurgical intervention was sought to obtain a pathologic diagnosis. Both cases were pathologically confirmed as glioblastoma. These cases demonstrate the importance of differentiation between brain metastases and primary brain tumours to ensure that the appropriate management strategy is implemented.

The incidence trends of primary brain tumors in Saskatchewan from 1970 to 2001

OBJECTIVE

There has been a paucity of information on the epidemiology of primary brain tumors (BTs) in Canada. This study documents epidemiology of primary BTs in Saskatchewan over three decades to define their current state, changing pattern over years and relative distribution in two geographically defined areas of the province.

METHODS

Data on all primary BTs from 1970 to 2001 from the Brain Tumor Registry in Saskatchewan was collected. The aggregate data on primary BTs including the time-series for incidence, age, geographic location and sex were statistically analyzed using SPSS 13. Poisson regression was used to model the incidence as a function of decade of diagnosis and age at the time of diagnosis.

RESULTS

The average annual incidence of primary BTs was 11.1 per 100,000 person-years (male 12.5 per 100.000 and female 9.8 per 100.000). Males constituted 54.5% of all these tumors. The age distribution of tumors was bimodal with peaks at 5 years and 65 years. During this time, the incidence of primary BTs has increase predominantly in non-malignant types. No difference was found in the rate of all the diagnosed primary BTs combined, meningioma and lymphoma between the northern part (Regina) and southern part (Saskatoon) of the province.

CONCLUSIONS

The incidence of BTs in Saskatchewan is more than previously reported in Canada. There is a temporal trend in increasing incidence of some of the BTs predominantly in the non-malignant types. No spatial difference in the incidence of primary BTs was shown in this province. These data will provide useful information to guide the future studies on BTs changing patterns, possible etiologies and efficient resource allocation for management of these diseases.

N. paucivorans infection presenting as a brain abscess

We report an intracerebral abscess caused by a recently identified nocardial species, in an immunocompetent individual without extraneural involvement.

A 63-year-old non-smoking Caucasian male with an unremarkable history of hypertension, presented with a 2-week history of personality changes including apathy, some difficulty walking, a tendency to veer to the left and a possible seizure. Preliminary assessment, including laboratory investigations were unremarkable. Computed tomography (CT) of his brain revealed a right frontal lobe multi-loculated, ring-enhancing lesion with vasogenic edema and associated mass effect (Figure 1). He was then referred to our institution.

A Novel Method in Predicting Immediate Postoperative Facial Nerve Function Post Acoustic Neuroma Excision

To determine whether the percentage calculated by dividing the amplitude of postexcision direct facial nerve stimulus responses (at pontomedullary junction) by the amplitude of distal ipsilateral transcutaneous (stylomastoid region) maximal stimulus responses and response amplitude progression by increasing stimulus intensities have predictive value for determining normal or near-normal (House-Brackmann Grade 1 or 2) immediate postoperative facial nerve function.

STUDY DESIGN

Intraoperative recordings of three muscle groups: 1) frontalis, 2) orbicularis oculi, and 3) orbicularis oris. Postexcision direct facial nerve stimulation at the pontomedullary junction and transcutaneous maximal facial nerve stimulation at the ipsilateral stylomastoid region and their associated response amplitudes were recorded.

SETTING

Tertiary referral center.

PATIENTS AND METHODS

Patients who underwent acoustic neuroma surgery from January 2004 to March 2006 with intraoperative facial nerve monitoring and an intact facial nerve after tumor excision were included. Recordings were available for 38 patients.

RESULTS

With a stimulus intensity of 0.3 mA at the root exit zone, there was an 81% positive predictive value in patients that exhibited a compound action potential of greater than 20% of maximum (sensitivity, 81%). This increased to 93% when the compound action potential was greater than 50% of maximum. When the amplitude increase was greater than 5 microV, there was a 77% positive predictive value (sensitivity, 87%).

CONCLUSION

The percentage of the response amplitude of direct facial nerve stimulation at the pontomedullary junction when compared with the maximum response amplitude of ipsilateral transcutaneous stimulation at the stylomastoid foramen is a good predictor of normal to near-normal immediate postoperative facial nerve function. Progression of amplitude response also seems to be a good predictor of normal to near-normal immediate postoperative facial nerve function.

Primary localized bilateral conjunctival amyloidosis and epiphora

BACKGROUND

Conjunctival amyloidosis is a rare entity, which can present with epiphora. The management options, including the surgical treatment of this disease, are illustrated with a case study.

METHODS

A combination of retrospective and prospective review of a patient's clinical findings, course and treatment outcome.

RESULTS

A middle-aged patient with epiphora due to localized conjunctival amyloidosis is described. The clinical course of the epiphora during a 10-year period revealed a decrease on the initially symptomatic side and involvement of the opposite side despite bilateral progressive lacrimal drainage stenosis. The pathophysiology of this phenomenon is discussed. The progressive conjunctival deposits in this patient eventually required operative debulking through a conjunctival approach. Medial ectropion and punctal stenoses were also simultaneously corrected. The patient became symptom free one week after these operative interventions.

CONCLUSIONS

Localized conjunctival amyloidosis is a chronic, slowly progressive disease, which is frequently bilateral. Associated ocular involvement does not seem to be a part of this disease, even with long-term follow-up. The treatment of associated epiphora requires an organized approach to the underlying cause(s). The epiphora may be managed by a staged correction of its pathogenic mechanisms.

Management of hydrocephalus associated with vestibular schwannoma and other cerebellopontine angle tumors

OBJECTIVE

Hydrocephalus (HCP) resulting from cerebellopontine angle (CPA) tumors is not rare. This retrospective study was designed to investigate the incidence of HCP and the clinical presentations, management options, and outcomes of HCP in 284 patients with CPA tumors.

METHODS

A retrospective study of 284 consecutive patients with CPA tumors (mostly vestibular schwannomas) treated from 1985 to 1996 at Toronto Western Hospital managed by one surgical team consisting of a neurosurgeon and a neuro-otologist.

RESULTS

Thirty-nine patients (13.7%) had radiographic and/or clinical evidence of HCP, 37 preoperatively and 2 postoperatively. Tumor type distribution was 33 vestibular schwannomas, 5 meningiomas, and 1 cavernous hemangioma. Only five patients (12%) had obvious obstruction at the fourth ventricular level. In 36 patients (92%), symptoms were mostly chronic and mild, consistent with normal pressure hydrocephalus. Multivariate analysis confirmed the strong association of tumor size and incidence of HCP (P < .0001). Four patients underwent permanent shunting before microsurgical tumor excision, mainly because of florid symptoms of HCP. Microsurgical tumor excision without preoperative shunting was performed in 23 patients, 5 of whom required postoperative shunting in the first 2 months after tumor excision. Eighteen patients (78%) did not need shunts after tumor resection. With regard to tumor size, the postoperatively shunted group did not differ from the patients who had surgery but did not require shunt treatment (P < 0.50). The remaining 10 patients with preoperative HCP received shunts as the only treatment (3 patients), stereotactic radiosurgery (3 patients), or expectant management (4 patients). Two other patients without preoperative HCP developed postoperative HCP and required shunts. Postoperatively, we observed a significant (P < 0.001) increase in the incidence of pseudomeningocele and a nonsignificant (P < 0.1) increase in cerebrospinal fluid leaks (rhinorrhea and/or otorrhea) in patients without shunts as compared with postoperative patients without HCP. The patients were followed after any treatment for a mean of 3.2 years (range, 6 mo-10 yr). Follow-up in the patients who had surgery but did not require a shunt revealed a 61% decrease in clinical symptoms related to HCP and a 75% decrease in radiographic signs of HCP.

CONCLUSION

In the presence of HCP, operative resection of CPA tumors can be performed without permanent cerebrospinal fluid shunting. Precautionary measures to decrease the incidence of postoperative complications related to cerebrospinal fluid leak in patients with preoperative HCP include meticulous obliteration of any exposed air cells, including those around the internal auditory canal, accurate restoration of the dural barrier, and temporary lowering of intracranial pressure with a ventricular or lumbar drain. Patients with persistent symptomatic HCP after tumor excision should be treated with a ventriculoperitoneal shunt. Delaying this decision until the postoperative period is safe and avoids unnecessary shunting in the majority of patients.

Subacute femoral compressive neuropathy from iliacus compartment hematoma

BACKGROUND

Traumatic retroperitoneal hematoma in the iliacus muscle is an unusual but potentially serious cause of femoral compression neuropathy.

CASE REPORT

We describe the clinical, imaging, and management features of a case of traumatic iliacus retroperitoneal hematoma with delayed manifestation of femoral neuropathy.

DISCUSSION

The anatomical substrate for hematoma formation with subacute compression of the femoral nerve is emphasized. A subacute compartment syndrome with progressive edema, swelling and ischemia of iliacus compartment is suggested as the underlying cause. Early fasciotomy with or without hematoma evacuation should be considered in order to provide rapid decompression and to minimize the chance of permanent nerve injury.

Intraoperative reduction of locked facets in the cervical spine by use of a modified interlaminar spreader: technical note

OBJECTIVE

Facet dislocations commonly require intraoperative reduction after closed reduction with traction has failed. Reduction should be performed in a gradual, controlled fashion to prevent additional inadvertent spinal cord compromise.

METHODS

We describe a new technique for safe and simple dorsal reduction of facet dislocations by use of a modified interlaminar spreader. This technique requires only minimal controlled manipulation of the spine.

RESULTS

We have used this technique in 52 consecutive patients with no complications or failures related to its use in open reduction. This technique increases the stability of the cervical spine after reduction because it limits bone removal from the facet joints.

CONCLUSION

This technique provides a feasible and reliable approach to open reduction of cervical facet dislocations via the posterior approach.

Spinal epidural arteriovenous fistula with intramedullary reflux. Case report

A spinal epidural arteriovenous fistula with secondary reflux into the perimedullary veins is a rare entity. The authors present such a case with a discussion of its pathophysiology and treatment. The mechanism for formation of a spinal dural arteriovenous fistula is outlined based on the anatomical substrates in this region.