A quantitative comparative surgical analysis of the endoscopic transorbital approach and frontotemporal-orbitozygomatic approach for extradural exposure of the cavernous sinus

OBJECTIVE

Recently, the endoscopic superior eyelid transorbital approach (SETA) has emerged as a potential alternative to access the cavernous sinus (CS). Several previous studies have attempted to quantitatively compare the traditional open anterolateral skull base approaches with transorbital exposure; however, these comparisons have been limited to the area of exposure provided by the bone opening and trajectory, and fail to account for the main avenues of exposure provided by subsequent requisite surgical maneuvers. The authors quantitatively compare the surgical access provided by the frontotemporal-orbitozygomatic (FTOZ) approach and the SETA following applicable periclinoid surgical maneuvers, evaluate the surgical exposure of key structures in each, and discuss optimal approach selection.

METHODS

SETA and FTOZ approaches were performed with subsequent applicable surgical maneuvers on 8 cadaveric heads. The lengths of exposure of cranial nerves (CNs) II-VI and the cavernous internal carotid artery; the areas of the space accessed within the supratrochlear, infratrochlear, and supramaxillary (anteromedial) triangles; the total area of exposure; and the angles of attack were measured and compared.

RESULTS

Exposure of the extradural CS was comparable between approaches, whereas access was significantly greater in the FTOZ approach compared with the SETA. The lengths of extradural exposure of CN III, V1, V2, and V3 were comparable between approaches. The FTOZ approach provided marginally increased exposure of CNs IV (20.9 ± 2.36 mm vs 13.4 ± 3.97 mm, p = 0.023) and VI (14.1 ± 2.44 mm vs 9.22 ± 3.45 mm, p = 0.066). The FTOZ also provided significantly larger vertical (44.5° ± 6.15° vs 18.4° ± 1.65°, p = 0.002) and horizontal (41.5° ± 5.40° vs 15.3° ± 5.06°, p < 0.001) angles of attack, and thus significantly greater surgical freedom, and provided significantly greater access to the supratrochlear (p = 0.021) and infratrochlear (p = 0.007) triangles, and significantly greater exposure of the cavernous internal carotid artery (17.2 ± 1.70 mm vs 8.05 ± 2.37 mm, p = 0.001). Total area of exposure was also significantly larger in the FTOZ, which provided wide access to the lateral wall of the CS as well as the possibility for intradural access.

CONCLUSIONS

This is the first study to quantitatively identify the relative advantages of the FTOZ and transorbital approaches at the target region following requisite surgical maneuvers. Understanding these data will aid in selecting an optimal approach and maneuver set based on target lesion size and location.

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.

The complete anterior petrosectomy: an expanded extended-middle fossa approach with removal of the infratrigeminal petrous apex and drilling of the lateral clivus

Intradural exposure in the extended middle fossa anterior transpetrosal approach is traditionally limited to the inferior petrosal sinus inferomedially. Expanding bone removal of the petrous apex around the petrous internal carotid artery (ICA), underneath the trigeminal ganglion/mandibular nerve, and into the lateral component of the clivus can significantly expand the limits of this approach beyond the inferior petrosal sinus and allows for exposure of the midline structures, aspects of the contralateral inferior clival region, and, when high riding, the vertebrobasilar junction. To date, no descriptive techniques for drilling into the lateral clivus in this approach have been published. The authors provide a detailed stepwise description of their complete anterior petrosectomy, in use at their institution, that involves skeletonization of the posteromedial petrous ICA, gentle elevation of the trigeminal ganglion/mandibular nerve, removal of the infratrigeminal petrous apex, and two techniques for drilling into the lateral clivus along the petroclival fissure. These techniques provide a direct and unobstructed corridor to the midpetroclival region and ventral brainstem with greater maneuverability and enhanced control of the midline structures, which is especially useful for resection of petroclival meningiomas, chondrosarcomas, and giant vascular lesions of the mid- and upper basilar artery and its proximal branches.

Quantitative analysis of external carotid artery bypass donor vessels by recipient and approach

INTRODUCTION

Utilization an in-situ pedicle of the external carotid artery (ECA) as an arterial donor can allow for the successful augmentation or replacement of flow to a large vascular territory. We propose a mathematical model for quantitatively analyzing and grading the suitability of donor and recipient bypass vessels based on a set of anatomical and surgical variables in order to predict which pair has the greatest possibility for success. Using this method, we analyze all of the potential donor-recipient pairs for each ECA donor vessel-including the superficial temporal (STA), middle meningeal (MMA), and occipital (OA) arteries.

METHODS

The ECA pedicles were dissected in frontotemporal, middle fossa, subtemporal, retrosigmoid, far lateral, suboccipital, supracerebellar, and occipital transtentorial approaches. For each approach, every potential donor-recipient pair was identified, and donor length and diameter were measured as well as depth of field, angle of exposure, ease of proximal control, maneuverability, and length and diameter of the recipient segment. Anastomotic pair scores were determined by adding the weighted donor and recipient.

RESULTS

The best overall anastomotic pairs were OA-vertebral artery (V3, 17.1) and STA-insular (M2, 16.3) and STA-sylvian (M3, 15.9) segments of the middle cerebral artery. Other strong anastomotic combinations were OA- telovelotonsillar (15) and OA- tonsilomedullary (14.9) segments of the posterior inferior cerebellar artery, and MMA-lateral pontomesencephalic segment of the superior cerebellar artery (14.2).

CONCLUSIONS

This novel model for anastamotic pair scoring can serve as a useful clinical tool for selecting the optimal donor, recipient, and approach combination that can help facilitate a successful bypass.

Safety and efficacy of Cesium-131 brachytherapy for brain tumors

BACKGROUND

The introduction of Cesium-131 (Cs-131) as a radiation source has led to a resurgence of brachytherapy for central nervous system (CNS) tumors. The aim of this study was to evaluate the safety and efficacy of the largest cohort of Cs-131 patients to-date.

METHODS

A retrospective review of all CNS tumors treated with resection and adjuvant Cs-131 brachytherapy at New York-Presbyterian/Weill Cornell from 2010 to 2021 was performed. Overall survival (OS) and local control (LC) were assessed with Kaplan-Meier methodology. Univariable analysis was conducted to identify patient factors associated with local recurrence or radiation necrosis.

RESULTS

Adjuvant Cs-131 brachytherapy following resection was performed in 119 patients with a median follow-up time of 11.8 (IQR 4.7-23.6) months and a mean of 22.3 +/-30.3 months. 1-year survival rates were 53.3% (95%CI 41.9-64.6%) for brain metastases (BrM), 45.9% (95%CI 24.8-67.0%) for gliomas, and 73.3% (95%CI 50.9-95.7%) for meningiomas. 1-year local control rates were 84.7% for BrM, 34.1% for gliomas, and 83.3% for meningiomas (p < 0.001). For BrM, local control was superior in NSCLC relative to other BrM pathologies (90.8% versus 76.5%, p = 0.039). Radiographic radiation necrosis (RN) was identified in 10 (8.4%) cases and demonstrated an association with smaller median tumor size (2.4 [IQR 1.8-2.7 cm] versus 3.1 [IQR 2.4-3.8 cm], p = 0.034). Wound complications occurred in 14 (11.8%) patients.

CONCLUSIONS

Cs-131 brachytherapy demonstrated a favorable safety and efficacy profile characterized by high rates of local control for all treated pathologies. The concept of brachytherapy has seen a resurgence given the excellent results when Cs-131 is used as a source.

Affordability impacts therapeutic intensity of acute management of severe traumatic brain injury patients: An exploratory study in Tanzania

Introduction

Quality health care in low and middle-income countries (LMICs) is constrained by financing of care.

Research question

What is the effect of ability to pay on critical care management of patients with severe traumatic brain injury (sTBI)?

Material and Methods

Data on sTBI patients admitted to a tertiary referral hospital in Dar-es-Salaam, Tanzania, were collected between 2016 and 2018, and included payor mechanisms for hospitalization costs. Patients were grouped as those who could afford care and those who were unable to pay.

Results

Sixty-seven patients with sTBI were included. Of those enrolled, 44 (65.7%) were able to pay and 15 (22.3%) were unable to pay costs of care upfront. Eight (11.9%) patients did not have a documented source of payment (unknown identity or excluded from further analysis). Overall mechanical ventilation rates were 81% (n=36) in the affordable group and 100% (n=15) in the unaffordable group (p=0.08). Computed tomography (CT) rates were 71.6% (n=48) overall, 100% (n=44) and 0% respectively (p<0.01); Surgical rates were 16.4% (n=11) overall, 18.2% (n=8) vs. 13.3% (n=2) (p=0.67) respectively. Two-week mortality was 59.7% overall (n=40), 47.7% (n=21) in the affordable group and 73.3% (n=11) in the unaffordable group (p=0.09) (adjusted OR 0.4; 95% CI: 0.07-2.41, p=0.32).

Discussion and Conclusion

Ability to pay appears to have a strong association with the use of head CT and a weak association with mechanical ventilation in the management of sTBI. Inability to pay increases redundant or sub-optimal care, and imposes a financial burden on patients and their relatives.

A novel 3D surgical neuroanatomy course for medical students: Outcomes from a pilot 6-week elective

BACKGROUND

Developing and maintaining a three-dimensional working knowledge of neuroanatomy is an essential skill in neurosurgery. However, conventional 2D head, neck, and neuroanatomy education is typically characterized by the separate rote learning of constituent tissues and often fails to provide learners with a contextual understanding of the relationships between these highly complex and interconnected structures. This can pose a significant challenge to medical students entering neurosurgery who lack a topographic understanding of intracranial anatomy.

METHODS

We report on the design and efficacy of a novel 6-part 3D surgical neuroanatomy pilot elective for medical students that utilized a navigation-based pedagogical technique with the goal of providing students with a framework for developing a 3D mental map of the skull base, neurovasculature, ventricular system, and associated brain regions. Students took on the perspective of physically traveling along the paths of key structures with a 360-degree view of surrounding anatomy such that they could appreciate the integration and relative spatial relationships of the varying tissues within the cranium. Mental navigation exercises and pre- and post-course surveys were used to assess students' baseline and learned familiarity with the different anatomical regions covered.

RESULTS

At the conclusion of the course, all students were able to successfully complete all of the multifaceted mental navigation exercises. Post-course survey data indicated that respondents perceived significant increases in their knowledge of cranial nerves; anterior, middle, and posterior skull base anatomy; anterior and posterior cranial circulation; and the ventricular system.

CONCLUSION

3D navigation-based fly-through instruction is a novel and effective technique for teaching complex anatomy and can provide learners with the foundational skills for developing and maintaining a 3D mental map of intracranial anatomy.

Intracranial Venous Alteration in Patients With Aneurysmal Subarachnoid Hemorrhage: Protocol for the Prospective and Observational SAH Multicenter Study (SMS)

Background

Arterial vasospasm has been ascribed as the responsible etiology of delayed cerebral infarction in patients with aneurysmal subarachnoid hemorrhage (aSAH), but other neurovascular structures may be involved. We present the protocol for a multicenter, prospective, observational study focused on analyzing morphological changes in cerebral veins of patients with aSAH.

Methods and Analysis

In a retrospective arm, we will collect head arterial and venous CT angiograms (CTA) of 50 patients with aSAH and 50 matching healthy controls at days 0–2 and 7–10, comparing morphological venous changes. A multicenter prospective observational study will follow. Patients aged ≥18 years of any gender with aSAH will be enrolled at 9 participating centers based on the predetermined eligibility criteria. A sample size of 52 aSAH patients is expected, and 52 healthy controls matched per age, gender, and comorbidities will be identified. For each patient, sequential CTA will be conducted upon admission (day 0–2), at 7–10 days, and at 14–21 days after aSAH, evaluating volumes and morphology of the cerebral deep veins and main cortical veins. One specialized image collecting center will analyze all anonymized CTA scans, performing volumetric calculation of targeted veins. Morphological venous changes over time will be evaluated using the Dice coefficient and the Jaccard index and scored using the Boeckh–Behrens system. Morphological venous changes will be correlated to clinical outcomes and compared between patients with aSAH and healthy-controls, and among groups based on surgical/endovascular treatments for aSAH.

Ethics and Dissemination

This protocol has been approved by the ethics committee and institutional review board of Ethikkommission, SALK, Salzburg, Austria, and will be approved at all participating sites. The study will comply with the Declaration of Helsinki. Written informed consent will be obtained from all enrolled patients or their legal tutors. We will present our findings at academic conferences and peer-reviewed journals.

Approved Protocol Version and Registration

Version 2, 09 June 2021.

Familial colloid cysts: not a chance occurrence

PURPOSE

Colloid cysts are rare, benign brain tumors of the third ventricle with an estimated population prevalence of 1 in 5800. Sudden deterioration and death secondary to obstructive hydrocephalus are well-described presentations in patients with a colloid cyst. Although historically conceptualized as driven by sporadic genetic events, a growing body of literature supports the possibility of an inherited predisposition.

METHODS

A prospective registry of patients with colloid cysts was maintained between 1996 and 2021. Data pertaining to a family history of colloid cyst was collected retrospectively; self-reporting was validated in each case by medical record or imaging review. Frequency of patients with a documented first-degree family member with a colloid cyst based on self-reporting was calculated. The rate of familial co-occurrence within our series was then compared to a systematic literature review and aggregation of familial case studies, as well as population-based prevalence rates of sporadic colloid cysts.

RESULTS

Thirteen cases with affected first-degree relatives were identified in our series. Of the entire cohort, 19/26 were symptomatic from the lesion (73%), 12/26 (46.2%) underwent resection, and 2/26 (7.7%) had sudden death from presumed obstructive hydrocephalus. The majority of transmission patterns were between mother and child (9/13). Compared with the estimated prevalence of colloid cysts, our FCC rate of 13 cases in 383 (3.4%) estimates a greater-than-chance rate of co-occurrence.

CONCLUSION

Systematic screening for FCCs may facilitate early recognition and treatment of indolent cysts, thereby preventing the rapid deterioration that can occur with an unrecognized third ventricular tumor. Furthermore, identifying a transmission pattern may yield more insight into the molecular and genetic underpinnings of colloid cysts.

Transseptal interforniceal endoscopic removal of superiorly recessed colloid cysts

OBJECTIVE

Transforaminal endoscopic colloid cyst resection is well described. However, some anatomical colloid cyst variants may warrant a modified approach. Rarely, colloid cysts separate the forniceal columns and grow superiorly within the leaflets of the septum pellucidum. Thus, the authors' goal was to characterize the imaging features, clinical presentation, surgical strategy, and outcomes of patients with this superiorly recessed colloid cyst variant.

METHODS

A retrospective evaluation of patients who underwent endoscopic resection of colloid cysts from 1999 to 2020 was performed. The patients were dichotomized depending on whether the cyst was located predominately below the forniceal columns or was superiorly recessed (forniceal column separation with variable intraseptal extension). This comparative cohort study focused on clinical presentation, imaging features, operative technique, and patient outcome.

RESULTS

In total, 182 patients were identified. Seventeen patients had colloid cysts that were defined as superiorly recessed and underwent transseptal interforniceal removal, and 165 patients underwent a standard transforaminal approach. Patients had similar demographic characteristics. However, transseptal cysts were on average larger (17.8 mm vs 11.4 mm, p < 0.0001), and these patients had a greater frontal-occipital horn ratio (0.45 vs 0.41, p = 0.012). They were also more likely to have undergone a previous resection (p = 0.02). The two cohorts had similar surgical outcomes, with no differences in extent of resection, recurrence, or complications.

CONCLUSIONS

Superiorly recessed intraseptal colloid cysts are larger and tend to splay the bodies of the fornix, thus requiring a parasagittal transseptal interforniceal endoscopic approach. This achieves complete removal with comparatively negligible morbidity or rare recurrence (5.9%).

Stereotactic radiosurgery for vestibular schwannomas in neurofibromatosis type 2 patients: a systematic review and meta-analysis

INTRODUCTION

Neurofibromatosis type 2 (NF2) is characterized by often bilateral vestibular schwannomas (VS) that result in progressive hearing loss and compression of nearby brainstem structures causing cranial nerve palsies. Treatment of these tumors remains challenging, as both surgical removal and expectant management can result in symptom progression. Stereotactic radiosurgery (SRS) has been investigated for the management of NF2-associated VS; however, the role, promises, and pitfalls of this treatment modality remain unclear.

METHODS

Ovid MEDLINE, EMBASE, Web of Science, and Cochrane Reviews were searched for studies assessing SRS outcome in NF2-associated VS only. Primary endpoints included tumor control, serviceable hearing, presence of tinnitus, and cranial nerve V and VII symptoms.

RESULTS

A total of 16 studies (589 patients harboring 750 tumors) were analyzed. Clinical tumor control was achieved in 88% of cases (95% CI 80-95%); salvage surgery was needed in 8% (95% CI 4-13%) of cases. Treatment resulted in a worsening of pre-treatment serviceable hearing (OR = 0.26, p < 0.01), increased facial nerve (OR = 1.62, p < 0.01) and trigeminal nerve (OR = 1.42, p = 0.07) impairment. The incidence of vestibular symptoms and hydrocephalus were not consistently reported and thus could not be assessed.

CONCLUSIONS

The treatment of NF2-associated VS continues to pose a challenge, as current SRS regimens result in impaired hearing and worse cranial nerve comorbidities, despite achieving high tumor control. It remains unclear if these findings have to be regarded as treatment complications or, rather, continued disease progression.

Corticothalamic Connectivity in Aneurysmal Subarachnoid Hemorrhage: Relationship with Disordered Consciousness and Clinical Outcomes

BACKGROUND

We present an exploratory analysis of the occurrence of early corticothalamic connectivity disruption after aneurysmal subarachnoid hemorrhage (SAH) and its correlation with clinical outcomes.

METHODS

We conducted a retrospective study of patients with acute SAH who underwent continuous electroencephalography (EEG) for impairment of consciousness. Only patients undergoing endovascular aneurysm treatment were included. Continuous EEG tracings were reviewed to obtain artifact-free segments. Power spectral analyses were performed, and segments were classified as A (only delta power), B (predominant delta and theta), C (predominant theta and beta), or D (predominant alpha and beta). Each incremental category from A to D implies greater preservation of corticothalamic connectivity. We dichotomized categories as AB for poor connectivity and CD for good connectivity. The modified Rankin Scale score at follow-up and in-hospital mortality were used as outcome measures.

RESULTS

Sixty-nine patients were included, of whom 58 had good quality EEG segments for classification: 28 were AB and 30 were CD. Hunt and Hess and World Federation of Neurological Surgeons grades were higher and the initial Glasgow Coma Scale score was lower in the AB group compared with the CD group. AB classification was associated with an adjusted odds ratio of 5.71 (95% confidence interval 1.61-20.30; p < 0.01) for poor outcome (modified Rankin Scale score 4-6) at a median follow-up of 4 months (interquartile range 2-6) and an odds ratio of 5.6 (95% confidence interval 0.98-31.95; p = 0.03) for in-hospital mortality, compared with CD.

CONCLUSIONS

EEG spectral-power-based classification demonstrates early corticothalamic connectivity disruption following aneurysmal SAH and may be a mechanism involved in early brain injury. Furthermore, the extent of this disruption appears to be associated with functional outcome and in-hospital mortality in patients with aneurysmal SAH and appears to be a potentially useful predictive tool that must be validated prospectively.

Outcomes following upfront radiation versus monitoring in atypical meningiomas: 16-year experience at a tertiary medical center

Background

The role of postoperative upfront radiotherapy (RT) in the management of gross totally resected atypical meningiomas remains unclear. This single-center retrospective review of newly diagnosed histologically confirmed cases of World Health Organization (WHO) Grade II atypical meningioma at Weill Cornell Medicine from 2004 to 2020 aims to compare overall survival (OS) and progression-free survival (PFS) of postoperative upfront RT versus observation, stratified by resection status (gross total resection [GTR] vs subtotal resection [STR]).

Methods

Ninety cases of atypical meningioma were reviewed (56% women; median age 61 years; median follow-up 41 months).

Results

In patients with GTR, hazard ratio (HR) of PFS was 0.09 for postoperative upfront RT versus observation alone (95% confidence interval [CI] 0.01–0.68; P = .02), though HR for OS was not significant (HR 0.46; 95% CI 0.05–4.45; P = .5). With RT, PFS was 100% at 12 and 36 months (compared to 84% and 63%, respectively, with observation); OS at 36 months (OS36) was 100% (compared to 94% with observation). In patients with STR, though PFS at 36 months was higher for RT arm versus observation (84% vs 74%), OS36 was 100% in both arms. HR was not significant (HR 0.76; 95% CI 0.16–3.5; P = .73).

Conclusions

This retrospective study suggests postoperative upfront RT following GTR of atypical meningioma is associated with improved PFS compared to observation. Further studies are required to draw conclusions about OS.

COVID-19: A Time Like No Other in (the Department of) Neurological Surgery

Coronavirus disease 2019 (COVID-19) has disrupted lives and indelibly impacted the practice of medicine since emerging as a pandemic in March 2020. For neurosurgery departments throughout the United States, the pandemic has created unique challenges across subspecialties in devising methods of triage, workflow, and operating room safety. Located in New York City, at the early epicenter of the COVID-19 crisis, the Weill Cornell Medicine Department of Neurological Surgery was disrupted and challenged in many ways, requiring adaptations in clinical operations, workforce management, research, and education. Through our department's collective experience, we offer a glimpse at how our faculty and administrators overcame obstacles, and transformed in the process, at the height of the COVID-19 pandemic.

Outcomes of stereotactic radiosurgery for large vestibular schwannomas: a systematic review and meta-analysis

Background

Large vestibular schwannomas (VS) pose a treatment challenge for both microsurgery (MS) and stereotactic radiosurgery (SRS). Technical developments have allowed for safer irradiation of large tumors. It remains unclear if SRS can achieve appropriate tumor control and acceptable cranial nerve toxicities. In this study, we assess outcomes of irradiation for large VS.

Methods

PubMed MEDLINE, EMBASE, Web of Science, and Cochrane were searched for all the studies assessing SRS outcome in large VS. Primary endpoints included clinical and radiographic tumor control, need for salvage surgery, serviceable hearing, cranial nerve V and VII impairment, presence of hydrocephalus requiring shunting, and presence of vertigo/dizziness.

Results

Twenty-two studies were identified that met selection criteria for analysis from an initial pool of 1272 reports. They were evaluated according to treatment protocol: 1) single-dose SRS (13 studies, 483 patients), 2) combination of MS and SRS (7 studies, 182 patients), and 3) fractionated SRS (3 studies, 82 patients). Tumor control was achieved in 89%, 94%, and 91% of patients, respectively. Odds ratios (ORs) of post- over pretreatment serviceable hearing were 0.42 (P < .01), 0.47 (P = .05), and 0.60 (P = .22); for facial nerve impairment, these ORs were 1.08 (P = .69), 3.45 (P = .28), and 0.87 (P = .71), respectively.

Conclusions

The management of large VS remains challenging. All treatment modalities resulted in high tumor control rates and worsening of pretreatment hearing. None, however, caused significant facial nerve impairment, suggesting that management strategies incorporating focal irradiation can be successful.

Efficacy and comorbidities of hypofractionated and single-dose radiosurgery for vestibular schwannomas: a systematic review and meta-analysis

Background

Vestibular schwannomas (VS) are tumors of the cerebellopontine angle with significant morbidity, causing hearing loss, tinnitus, and trigeminal and facial nerve compromise. An effective alternative to microsurgical resection is stereotactic radiosurgery (SRS), which can be delivered in either single-fraction (SRS) or hypofractionated stereotactic radiotherapy (hSRT) (3-5 treatments) regimens. It remains unclear which fractionation regimen provides superior outcomes.

Methods

Ovid MEDLINE, EMBASE, CINAHL, and Cochrane Reviews were searched for studies either comparing hSRT with SRS or focusing on hSRT alone in treating VS. Primary endpoints included tumor control, serviceable hearing, tinnitus, and cranial nerve V and VII symptoms. A random-effects analysis was employed to compare pre- and post-treatment effects (hSRT alone) or SRS and hSRT outcomes (two-arm studies).

Results

This analysis included 21 studies focusing on hSRT alone and 13 studies comparing SRS and hSRT. Significant heterogeneity was observed. Overall, when hSRT was analyzed alone, crude tumor control was achieved in 94% (95% CI: 88%, 99%) of 1571 patients. There was no difference between pre- and post-treatment odds ratios (OR) of tinnitus, facial, or trigeminal impairment. Serviceable hearing was diminished following hSRT (OR = 0.60, 95% CI: 0.44, 0.83). Comparison with SRS showed no difference with respect to tumor control, serviceable hearing, trigeminal or facial nerve impairment.

Conclusions

hSRT achieved excellent tumor control and, with the exception of serviceable hearing, did not result in worse post-treatment cranial nerve symptomatology. Analysis of comparative studies between hSRT and SRS did not reveal any significant difference in either tumor control or treatment morbidities.

Severe traumatic brain injury management in Tanzania: analysis of a prospective cohort

OBJECTIVE

Given the high burden of neurotrauma in low- and middle-income countries (LMICs), in this observational study, the authors evaluated the treatment and outcomes of patients with severe traumatic brain injury (TBI) accessing care at the national neurosurgical institute in Tanzania.

METHODS

A neurotrauma registry was established at Muhimbili Orthopaedic Institute, Dar-es-Salaam, and patients with severe TBI admitted within 24 hours of injury were included. Detailed emergency department and subsequent medical and surgical management of patients was recorded. Two-week mortality was measured and compared with estimates of predicted mortality computed with admission clinical variables using the Corticoid Randomisation After Significant Head Injury (CRASH) core model.

RESULTS

In total, 462 patients (mean age 33.9 years) with severe TBI were enrolled over 4.5 years; 89% of patients were male. The mean time to arrival to the hospital after injury was 8 hours; 48.7% of patients had advanced airway management in the emergency department, 55% underwent cranial CT scanning, and 19.9% underwent surgical intervention. Tiered medical therapies for intracranial hypertension were used in less than 50% of patients. The observed 2-week mortality was 67%, which was 24% higher than expected based on the CRASH core model.

CONCLUSIONS

The 2-week mortality from severe TBI at a tertiary referral center in Tanzania was 67%, which was significantly higher than the predicted estimates. The higher mortality was related to gaps in the continuum of care of patients with severe TBI, including cardiorespiratory monitoring, resuscitation, neuroimaging, and surgical rates, along with lower rates of utilization of available medical therapies. In ongoing work, the authors are attempting to identify reasons associated with the gaps in care to implement programmatic improvements. Capacity building by twinning provides an avenue for acquiring data to accurately estimate local needs and direct programmatic education and interventions to reduce excess in-hospital mortality from TBI.

[68Ga]-DOTATATE PET/MRI as an adjunct imaging modality for radiation treatment planning of meningiomas

Background

Meningiomas express high levels of somatostatin receptor 2 (SSTR2). SSTR2-targeted PET imaging with [⁶⁸Ga]-DOTATATE can aid with distinguishing residual meningioma from reactive changes in the postoperative setting. We present initial dosimetric analyses, acute events, and local control data utilizing [⁶⁸Ga]-DOTATATE PET/MRI-assisted target delineation for prospectively-treated intermediate-risk meningiomas.

Methods

Twenty-nine patients underwent DOTATATE PET/MRI meningioma evaluation in 2019. Eight patients with 9 postoperative meningiomas met RTOG 0539 intermediate-risk criteria (recurrent WHO grade I, 1/9; WHO grade II, 8/9). Target volumes were created using DOTATATE PET/MRI to determine residual disease and received a nominal dose of 35.0 Gy over 5 fractions. For comparison, cases were recontoured and planned with MRI alone per RTOG 0539 guidelines. Mean and maximum equivalent 2 Gy doses were generated for target volumes and organs at risk (OAR) within 1 cm of the PTV and compared using Wilcoxon matched pairs signed rank test.

Results

DOTATATE PET/MRI-guided planning significantly reduced mean PTV (11.12 cm³ compared to 71.39 cm³ based on MRI alone, P < .05) and mean and max dose to the whole brain, optic nerves, and scalp. PET/MRI plans resulted in at least 50% reduction of mean and max doses to the lens, eyes, chiasm, cochlea, brainstem, and hippocampi. One patient experienced focal alopecia. There were no local recurrences at 6 months.

Conclusion

Incorporating DOTATATE-PET/MRI for postoperative target delineation in patients with intermediate-risk intracranial meningiomas results in PTV reduction and decreased OAR dose. Our findings warrant larger studies evaluating DOTATATE-PET/MRI in the radiotherapeutic planning of postoperative meningiomas.

Intracranial Aneurysms: Does Size Really Matter?

BACKGROUND

To stratify the risk of aneurysmal rupture, size remains the primary criterion as proposed by 2 ISUIA (International Study of Unruptured Intracranial Aneurysms) trials that recommend the observation of ≤7 mm aneurysms because of their low propensity to rupture. These recommendations are controversial, given the severe outcomes following hemorrhage.

OBJECTIVE

To retrospectively assess whether size correlates with aneurysmal rupture, and to analyze outcomes of endovascular and microsurgical procedures.

METHODS

All aneurysms presenting between 2016 and 2019 were reviewed. Age, gender, comorbidities, ruptured status, modes of treatment, and their outcomes were noted. Regression analysis was performed to correlate size with rupture. The type of intervention was based on clinical and aneurysmal characteristics and the likelihood of obliteration.

RESULTS

Of the 668 aneurysms, 116 had ruptured. In size groups 0 to 6 mm,  7 to 12 mm,  13 to 18 mm,  18 to 24 mm, and giant, the ruptured aneurysms were 60.3%, 30.2%, 1.7%, 0.9%, and 6.9%, respectively. The majority (423) were managed endovascularly, of which 84 (19.9%) were ruptured. A total of 97 (14.5%) underwent clipping, of which 31 were ruptured. The mean modified Rankin Scale for both treated groups was zero. One death in each group and a single brainstem stroke in the coiled group were noted. A total of 139 were followed, of which none had ruptured. The mean modified Raymond-Roy classification for endovascular therapy was 1.1, with 380 completely occluded; 15 had a score of 2, and 28 of score 3.

CONCLUSION

The ruptured aneurysms were mostly smaller than reported previously. Surgical clipping was at equipoise with endovascular treatments. Further studies to correlate aneurysmal characteristics to the risk of rupture are needed.

Hypertonic Saline is Superior to Mannitol for the Combined Effect on Intracranial Pressure and Cerebral Perfusion Pressure Burdens in Patients With Severe Traumatic Brain Injury

BACKGROUND

Hypertonic saline (HTS) and mannitol are effective in reducing intracranial pressure (ICP) after severe traumatic brain injury (TBI). However, their simultaneous effect on the cerebral perfusion pressure (CPP) and ICP has not been studied rigorously.

OBJECTIVE

To determine the difference in effects of HTS and mannitol on the combined burden of high ICP and low CPP in patients with severe TBI.

METHODS

We performed a case-control study using prospectively collected data from the New York State TBI-trac® database (Brain Trauma Foundation, New York, New York). Patients who received only 1 hyperosmotic agent, either mannitol or HTS for raised ICP, were included. Patients in the 2 groups were matched (1:1 and 1:2) for factors associated with 2-wk mortality: age, Glasgow Coma Scale score, pupillary reactivity, hypotension, abnormal computed tomography scans, and craniotomy. Primary endpoint was the combined burden of ICPhigh (> 25 mm Hg) and CPPlow (< 60 mm Hg).

RESULTS

There were 25 matched pairs for 1:1 comparison and 24 HTS patients matched to 48 mannitol patients in 1:2 comparisons. Cumulative median osmolar doses in the 2 groups were similar. In patients treated with HTS compared to mannitol, total number of days (0.6 ± 0.8 vs 2.4 ± 2.3 d, P < .01), percentage of days with (8.8 ± 10.6 vs 28.1 ± 26.9%, P < .01), and the total duration of ICPhigh + CPPlow (11.12 ± 14.11 vs 30.56 ± 31.89 h, P = .01) were significantly lower. These results were replicated in the 1:2 match comparisons.

CONCLUSION

HTS bolus therapy appears to be superior to mannitol in reduction of the combined burden of intracranial hypertension and associated hypoperfusion in severe TBI patients.

Risk of Ischemic Stroke in Patients With Coronavirus Disease 2019 (COVID-19) vs Patients With Influenza

IMPORTANCE

It is uncertain whether coronavirus disease 2019 (COVID-19) is associated with a higher risk of ischemic stroke than would be expected from a viral respiratory infection.

OBJECTIVE

To compare the rate of ischemic stroke between patients with COVID-19 and patients with influenza, a respiratory viral illness previously associated with stroke.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study was conducted at 2 academic hospitals in New York City, New York, and included adult patients with emergency department visits or hospitalizations with COVID-19 from March 4, 2020, through May 2, 2020. The comparison cohort included adults with emergency department visits or hospitalizations with influenza A/B from January 1, 2016, through May 31, 2018 (spanning moderate and severe influenza seasons).

EXPOSURES

COVID-19 infection confirmed by evidence of severe acute respiratory syndrome coronavirus 2 in the nasopharynx by polymerase chain reaction and laboratory-confirmed influenza A/B.

MAIN OUTCOMES AND MEASURES

A panel of neurologists adjudicated the primary outcome of acute ischemic stroke and its clinical characteristics, mechanisms, and outcomes. We used logistic regression to compare the proportion of patients with COVID-19 with ischemic stroke vs the proportion among patients with influenza.

RESULTS

Among 1916 patients with emergency department visits or hospitalizations with COVID-19, 31 (1.6%; 95% CI, 1.1%-2.3%) had an acute ischemic stroke. The median age of patients with stroke was 69 years (interquartile range, 66-78 years); 18 (58%) were men. Stroke was the reason for hospital presentation in 8 cases (26%). In comparison, 3 of 1486 patients with influenza (0.2%; 95% CI, 0.0%-0.6%) had an acute ischemic stroke. After adjustment for age, sex, and race, the likelihood of stroke was higher with COVID-19 infection than with influenza infection (odds ratio, 7.6; 95% CI, 2.3-25.2). The association persisted across sensitivity analyses adjusting for vascular risk factors, viral symptomatology, and intensive care unit admission.

CONCLUSIONS AND RELEVANCE

In this retrospective cohort study from 2 New York City academic hospitals, approximately 1.6% of adults with COVID-19 who visited the emergency department or were hospitalized experienced ischemic stroke, a higher rate of stroke compared with a cohort of patients with influenza. Additional studies are needed to confirm these findings and to investigate possible thrombotic mechanisms associated with COVID-19.

Risk of Ischemic Stroke in Patients with Covid-19 versus Patients with Influenza

Importance:

Case series without control groups suggest that Covid-19 may cause ischemic stroke, but whether Covid-19 is associated with a higher risk of ischemic stroke than would be expected from a viral respiratory infection is uncertain.

Objective:

To compare the rate of ischemic stroke between patients with Covid-19 and patients with influenza, a respiratory viral illness previously linked to stroke.

Design:

A retrospective cohort study.

Setting:

Two academic hospitals in New York City.

Participants:

We included adult patients with emergency department visits or hospitalizations with Covid-19 from March 4, 2020 through May 2, 2020. Our comparison cohort included adult patients with emergency department visits or hospitalizations with influenza A or B from January 1, 2016 through May 31, 2018 (calendar years spanning moderate and severe influenza seasons).

Exposures:

Covid-19 infection confirmed by evidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the nasopharynx by polymerase chain reaction, and laboratory-confirmed influenza A or B.

Main Outcomes and Measures:

A panel of neurologists adjudicated the primary outcome of acute ischemic stroke and its clinical characteristics, etiological mechanisms, and outcomes. We used logistic regression to compare the proportion of Covid-19 patients with ischemic stroke versus the proportion among patients with influenza.

Results:

Among 2,132 patients with emergency department visits or hospitalizations with Covid-19, 31 patients (1.5%; 95% confidence interval [CI], 1.0%-2.1%) had an acute ischemic stroke. The median age of patients with stroke was 69 years (interquartile range, 66-78) and 58% were men. Stroke was the reason for hospital presentation in 8 (26%) cases. For our comparison cohort, we identified 1,516 patients with influenza, of whom 0.2% (95% CI, 0.0-0.6%) had an acute ischemic stroke. After adjustment for age, sex, and race, the likelihood of stroke was significantly higher with Covid-19 than with influenza infection (odds ratio, 7.5; 95% CI, 2.3-24.9).

Conclusions and Relevance:

Approximately 1.5% of patients with emergency department visits or hospitalizations with Covid-19 experienced ischemic stroke, a rate 7.5-fold higher than in patients with influenza. Future studies should investigate the thrombotic mechanisms in Covid-19 in order to determine optimal strategies to prevent disabling complications like ischemic stroke.

Surgical Management of Posterior Communicating Artery Aneurysms in the Presence of a Low-Coursing Internal Carotid Artery and Narrowed Retrocarotid Window

BACKGROUND

Anatomical variations of the course of the internal carotid artery (ICA) may complicate surgical clipping of posterior communicating artery (PCoA) aneurysms by narrowing the retrocarotid window. We evaluated the efficacy of the periclinoid surgical maneuvers for expanding the retrocarotid window and analyzed computed tomography angiography (CTA) data from patients with PCoA aneurysms to define parameters for low-coursing ICAs.

METHODS

Using cadaveric specimens, standard pterional craniotomies were fashioned and extradural or intradural periclinoid surgical maneuvers-cutting of the meningo-orbital band, anterior clinoidectomy, and cutting of the distal dural ring (DDR)-were performed, and their relative advantages for expanding the retrocarotid window were assessed. Additionally, preoperative CTA data from 24 patients with PCoA aneurysms used to calculate the angles of the ICA relative to the skull base.

RESULTS

Periclinoid maneuvers, especially the anterior clinoidectomy, provided additional exposure of the retrocarotid space. Cutting of the DDR allowed for partial mobilization of the ICA and widened the retrocarotid surgical window, enhancing maneuverability. The anterior clinoidectomy with cutting of the DDR allowed for enhanced exposure of the medial, middle, and posterolateral aspects of the retrocarotid space. Cutting the anterior petroclinoid fold and mobilizing cranial nerve III provided wide exposure of the lateral aspect of retrocarotid space.

CONCLUSION

When clipping PCoA aneurysms in the presence of normal-coursing ICAs (approximately ≥30° ICA angle), a standard pterional craniotomy with anterior clinoidectomy and cutting of the DDR allows for substantial expansion of the retrocarotid window.

Non-Traumatic Subdural Hemorrhage and Risk of Arterial Ischemic Events

Background and Purpose- The risk of arterial ischemic events after subdural hemorrhage (SDH) is poorly understood. This study aimed to evaluate the risk of acute ischemic stroke and myocardial infarction among patients with and without nontraumatic SDH. Methods- We performed a retrospective cohort study using claims data from 2008 through 2014 from a nationally representative sample of Medicare beneficiaries. The exposure was nontraumatic SDH. Our primary outcome was an arterial ischemic event, a composite of acute ischemic stroke and acute myocardial infarction. Secondary outcomes were ischemic stroke alone and myocardial infarction alone. We used validated International Classification of Diseases, Ninth Revision, Clinical Modification diagnosis codes to identify our predictor and outcomes. Using Cox regression and corresponding survival probabilities, adjusted for demographics and vascular comorbidities, we computed the hazard ratio in 4-week intervals after SDH discharge. We performed secondary analyses stratified by strong indications for antithrombotic therapy (composite of atrial fibrillation, peripheral vascular disease, valvular heart disease, and venous thromboembolism). Results- Among 1.7 million Medicare beneficiaries, 2939 were diagnosed with SDH. In the 4 weeks after SDH, patients' risk of an arterial ischemic event was substantially increased (hazard ratio, 3.6 [95% CI, 1.9-5.5]). There was no association between SDH diagnosis and arterial ischemic events beyond 4 weeks. In secondary analysis, during the 4 weeks after SDH, patients' risk of ischemic stroke was increased (hazard ratio, 4.2 [95% CI, 2.1-7.3]) but their risk of myocardial infarction was not (hazard ratio, 0.8 [95% CI, 0.2-1.7]). Patients with strong indications for antithrombotic therapy had increased risks for arterial ischemic events similar to patients in the primary analysis, but those without such indications did not demonstrate an increased risk for arterial ischemic events. Conclusions- Among Medicare beneficiaries, we found a heightened risk of arterial ischemic events driven by an increased risk of ischemic stroke, in the 4 weeks after nontraumatic SDH. This increased risk may be due to interruption of antithrombotic therapy after SDH diagnosis.

Differences in Admission Blood Pressure Among Causes of Intracerebral Hemorrhage

Background and Purpose- It is unknown whether admission systolic blood pressure (SBP) differs among causes of intracerebral hemorrhage (ICH). We sought to elucidate an association between admission BP and ICH cause. Methods- We compared admission SBP across ICH causes among patients in the Cornell Acute Stroke Academic Registry, which includes all adults with ICH at our center from 2011 through 2017. Trained analysts prospectively collected demographics, comorbidities, and admission SBP, defined as the first recorded value in the emergency department or on transfer from another hospital. ICH cause was adjudicated by a panel of neurologists using the SMASH-U criteria. We used ANOVA to compare mean admission SBP among ICH causes. We used multiple linear regression to adjust for age, sex, race, Glasgow Coma Scale score, and hematoma size. In secondary analyses, we compared hourly SBP measurements during the first 72 hours after admission, using mixed-effects linear models adjusted for the covariates above plus antihypertensive agents. Results- Among 484 patients with ICH, admission SBP varied significantly across ICH causes, ranging from 138 (±24) mm Hg in those with structural vascular lesions to 167 (±35) mm Hg in those with hypertensive ICH (P<0.001). The mean admission SBP in hypertensive ICH was 17 (95% CI, 11-24) mm Hg higher than in ICH of all other causes combined. These differences remained significant after adjustment for age, sex, race, Glasgow Coma Scale score, and hematoma size (P<0.001), and this persisted throughout the first 72 hours of hospitalization (P<0.001). Conclusions- In a single-center ICH registry, SBP varied significantly among ICH causes, both on admission and during hospitalization. Our results suggest that BP in the acute post-ICH setting is at least partly associated with ICH cause rather than simply representing a physiological reaction to the ICH itself.

On-Demand Intraoperative 3-Dimensional Printing of Custom Cranioplastic Prostheses

BACKGROUND

Currently, implantation of patient-specific cranial prostheses requires reoperation after a period for design and formulation by a third-party manufacturer. Recently, 3-dimensional (3D) printing via fused deposition modeling has demonstrated increased ease of use, rapid production time, and significantly reduced costs, enabling expanded potential for surgical application. Three-dimensional printing may allow neurosurgeons to remove bone, perform a rapid intraoperative scan of the opening, and 3D print custom cranioplastic prostheses during the remainder of the procedure.

OBJECTIVE

To evaluate the feasibility of using a commercially available 3D printer to develop and produce on-demand intraoperative patient-specific cranioplastic prostheses in real time and assess the associated costs, fabrication time, and technical difficulty.

METHODS

Five different craniectomies were each fashioned on 3 cadaveric specimens (6 sides) to sample regions with varying topography, size, thickness, curvature, and complexity. Computed tomography-based cranioplastic implants were designed, formulated, and implanted. Accuracy of development and fabrication, as well as implantation ability and fit, integration with exiting fixation devices, and incorporation of integrated seamless fixation plates were qualitatively evaluated.

RESULTS

All cranioprostheses were successfully designed and printed. Average time for design, from importation of scan data to initiation of printing, was 14.6 min and average print time for all cranioprostheses was 108.6 min.

CONCLUSION

On-demand 3D printing of cranial prostheses is a simple, feasible, inexpensive, and rapid solution that may help improve cosmetic outcomes; significantly reduce production time and cost-expanding availability; eliminate the need for reoperation in select cases, reducing morbidity; and has the potential to decrease perioperative complications including infection and resorption.

Association of Seizure Occurrence with Aneurysm Treatment Modality in Aneurysmal Subarachnoid Hemorrhage Patients

BACKGROUND

Data on new-onset seizures after treatment of aneurysmal subarachnoid hemorrhage (aSAH) patients are limited and variable. We examined the association between new-onset seizures after aSAH and aneurysm treatment modality, as well their relationship with initial clinical severity of aSAH and outcomes.

METHODS

This is a retrospective cohort study of all aSAH patients admitted to our institution over a 6-year period. 'Seizures' were defined as any observed clinical seizure or electrographic seizure on continuous electroencephalogram (cEEG) recordings, as determined by the reviewing neurophysiologist. Subgroup analyses were performed in low-grade (Hunt-Hess 1-3) and high-grade (Hunt-Hess 4-5) patients. Outcomes measures were Glasgow Coma Score (GCS) at intensive care unit (ICU) discharge and modified Rankin Scale (mRS) at outpatient follow-up.

RESULTS

There were 282 patients with aSAH; 203 (72.0%) suffered low-grade and 79 (28%) high-grade aSAH. Patients were treated with endovascular coiling (N = 194, 68.8%) or surgical clipping (N = 66, 23.4%). Eighteen (6.4%) patients had seizures, of whom 10 (5.5%) had aneurysm coiling and 7 (10.6%) underwent clipping (p = 0.15). In low-grade patients, seizures occurred less frequently (p = 0.016) and were more common after surgical clipping (p = 0.0089). Seizures correlated with lower GCS upon ICU discharge (p < 0.001), in clipped (p = 0.011) and coiled (p < 0.001) patients and in low-grade aSAH (p < 0.001). Seizures correlated with higher mRS on follow-up (p < 0.001), in clipped (p = 0.032) and coiled (p = 0.004) patients and in low-grade aSAH (p = 0.003).

CONCLUSIONS

New-onset seizures after aSAH occurred infrequently, and their incidence after aneurysm clipping versus coiling was not significantly different. However, in low-grade patients, new seizures were more frequently associated with clipping than coiling. Additionally, non-convulsive seizures did not occur in low-grade patients treated with coiling. These findings may explain, in part, previous work suggesting better outcomes in coiled patients and encourage physicians to have a lower threshold for cEEG utilization in low-grade patients suspected to have acute seizures after surgical clipping.

On the Surgical Implications of Peritrigeminal Perforating Vessels in Microvascular Decompression

BACKGROUND

Perforating branches arising from the superior cerebellar artery (SCA) or anterior inferior cerebellar artery (AICA) that pierces the brainstem within 5 mm of the trigeminal root may limit offending vessel transposition during microvascular decompression for trigeminal neuralgia.

OBJECTIVE

To investigate the microsurgical anatomy of peritrigeminal perforators and evaluate their effect on the mobility of the SCA and AICA. Additionally, we propose strategies for mitigating the potential complications caused by the presence of short peritrigeminal perforators.

METHODS

Retrosigmoid approaches and exposure of the upper cerebellopontine angle were performed on 11 cadaveric heads (22 sides). The number, origin, and course of perforators were recorded and each was classified as either type I, short straight (<3 mm); type II, long straight perforators (>3 mm); or type III, long circumflex (>3 mm). Transposition of each SCA and AICA away from trigeminal nerve was performed, and degree of mobilization was evaluated and graded.

RESULTS

A total of 123 perforators were identified, of which 44 were considered peritrigeminal. Of these, 19 arose from the AICA, 18 from the SCA, and 7 from the basilar artery. Type I peritrigeminal perforators were the most common at 77.3%. Transposition or interposition of the parent vessel was not possible in 8 (47.1%) instances.

CONCLUSION

Identification of inhibiting perforators is essential before performing microvascular decompression to avoid ischemic injury to the brainstem. The presence of type I perforators may necessitate extensive arachnoid dissection and use of an interpositioning technique with minimal repositioning of the offending vessel.

Dynamic contrast-enhanced magnetic resonance imaging perfusion characteristics in meningiomas treated with resection and adjuvant radiosurgery

OBJECTIVE

There is a need for advanced imaging biomarkers to improve radiation treatment planning and response assessment. T1-weighted dynamic contrast-enhanced perfusion MRI (DCE MRI) allows quantitative assessment of tissue perfusion and blood-brain barrier dysfunction and has entered clinical practice in the management of primary and secondary brain neoplasms. The authors sought to retrospectively investigate DCE MRI parameters in meningiomas treated with resection and adjuvant radiation therapy using volumetric segmentation.

METHODS

A retrospective review of more than 300 patients with meningiomas resected between January 2015 and December 2018 identified 14 eligible patients with 18 meningiomas who underwent resection and adjuvant radiotherapy. Patients were excluded if they did not undergo adjuvant radiation therapy or DCE MRI. Demographic and clinical characteristics were obtained and compared to DCE perfusion metrics, including mean plasma volume (vp), extracellular volume (ve), volume transfer constant (Ktrans), rate constant (kep), and wash-in rate of contrast into the tissue, which were derived from volumetric analysis of the enhancing volumes of interest.

RESULTS

The mean patient age was 64 years (range 49–86 years), and 50% of patients (7/14) were female. The average tumor volume was 8.07 cm3 (range 0.21–27.89 cm3). The median Ki-67 in the cohort was 15%. When stratified by median Ki-67, patients with Ki-67 greater than 15% had lower median vp (0.02 vs 0.10, p = 0.002), and lower median wash-in rate (1.27 vs 4.08 sec−1, p = 0.04) than patients with Ki-67 of 15% or below. Logistic regression analysis demonstrated a statistically significant, moderate positive correlation between ve and time to progression (r = 0.49, p < 0.05). Furthermore, there was a moderate positive correlation between Ktrans and time to progression, which approached, but did not reach, statistical significance (r = 0.48, p = 0.05).

CONCLUSIONS

This study demonstrates a potential role for DCE MRI in the preoperative characterization and stratification of meningiomas, laying the foundation for future prospective studies incorporating DCE as a biomarker in meningioma diagnosis and treatment planning.

Preoperative identification of the initial burr hole site in retrosigmoid craniotomies: A teaching and technical note

BACKGROUND

When fashioning a retrosigmoid craniotomy, precise placement of the initial burr hole is crucial to avoid iatrogenic sinusal injury and to facilitate a corridor that allows for minimal cerebellar retraction.

METHODS

3D CT reconstructions of 16 cadaveric sides were used to identify and measure three discrete anatomical points. These three points and distances between them were plotted onto the surface of the skull using a digital caliper to identify the optimal burr hole location. This technique was subsequently applied in 20 clinical cases.

RESULTS

Optimal burr hole placement was achieved in 87.5% of specimens and, with minor refinement, 100% of clinical cases with no significant increase in operative time. Preoperative planning took an average of 10 minutes.

CONCLUSION

This technique for localizing the location of the initial retrosigmoid burr hole is a simple, safe, reliable, rapid, and inexpensive solution for surgeons who do not have regular access to neuronavigation.

Optimizing Patient Access During an Emergency While Using Intraoperative Computed Tomography

BACKGROUND

As minimally invasive spine surgery evolves, spine surgeons increasingly rely on advanced intraoperative computed tomography (iCT). iCT provides rapid acquisition of high-resolution images, reduces radiation exposure, improves surgical accuracy, and decreases operative time. However, all iCT systems currently available pose a patient safety risk as their physical space requirements limit patient access in the event of an emergency, particularly when patients are in the prone position. After a near-cardiac arrest at our institution during posterior cervical spine surgery, it was apparent that the presence of the iCT complicated the ability to rapidly reposition the patient in order to provide appropriate resuscitation.

METHODS

To ensure our ability to provide timely care during an emergency, we determined that a process which included all members of the operating room (OR) team was required. We held an initial planning meeting where a detailed plan-of-action was created, reviewed, and revised in response to feedback from all stakeholders. We then simulated a cardiac arrest to test our resuscitation plan with all members of the neurosurgery team. A mannequin was positioned prone on an OR table within the iCT, and a resuscitation plan was created.

RESULTS

The team orchestrated the mock resuscitation, and the time of cardiac arrest in the prone position to supine repositioning required 110 seconds. The simulation was recorded for post-"code" performance review. Application of the protocol during an actual cardiac arrest was associated with successful restoration of spontaneous circulation and full recovery.

CONCLUSIONS

The development and rehearsal of an emergency plan of action greatly facilitated the timely responsiveness of the neurosurgical OR team during a simulated cardiac arrest and was an effective way to identify and address key logistical issues regarding the use of an iCT system.

Treatment of Unruptured Brain Arteriovenous Malformations: A Single-Center Experience of 86 Patients and a Critique of the A Randomized Trial of Unruptured Brain Arteriovenous Malformations (ARUBA) Trial

OBJECTIVE

The A Randomized Trial of Unruptured Brain Arteriovenous Malformations (ARUBA) trial has received fierce criticism, including considerable selection bias, poor generalizability, questionable clinical practices (only 15.8% underwent surgical resection, the gold standard for arteriovenous malformation [AVM] treatment), and short follow-up (33 months) for a disease process that carries a life-long risk. In this study, we sought to present our own experience treating unruptured brain AVMs to provide supporting evidence of the ARUBA trial criticism.

METHODS

All cases of treated brain AVMs from 2004 to 2017 at our institution were retrospectively reviewed and included in the analysis if they met ARUBA trial inclusion criteria. The primary outcome was symptomatic stroke or death. Secondary outcomes included AVM obliteration, long-term clinical impairment (modified Rankin Scale score >1), and new major or minor postoperative deficit.

RESULTS

Of the 245 reviewed cases, 86 met the ARUBA trial criteria. Treatment included microsurgical resection alone (2.3%), preoperative embolization followed by microsurgical resection (62.8%), stereotactic radiosurgery alone (10.5%), embolization followed by stereotactic radiosurgery (15.1%), and embolization alone (9.3%). The primary outcome was met in 8.3%, new perioperative major and minor complications occurred in 5.8% and 12.8%, and long-term clinical impairment in 4.5%. AVM obliteration was observed in 92.4% overall and in 100% of patients who underwent surgical resection.

CONCLUSIONS

The criticism of the ARUBA trial is warranted, as our study found that treatment of unruptured brain AVMs has an acceptable safety profile when approached in a multidisciplinary manner at an experienced institution, using surgical resection as the primary treatment modality when applicable.

Clinical improvement associated with targeted interruption of the cerebellothalamic tract following MR-guided focused ultrasound for essential tremor

OBJECTIVE

The objective of this study was to evaluate the utility of diffusion tensor imaging (DTI) tractography–based targeting of the dentatorubrothalamic tract (DRT) for magnetic resonance–guided focused ultrasound (MRgFUS) thalamotomy in patients with essential tremor (ET) and correlate postprocedural tract disruption with clinical outcomes.

METHODS

Four patients received preprocedural and immediate postprocedural DTI in addition to traditional anatomical MRI sequences for MRgFUS thalamotomy. Optimal ablation sites were selected based on the patient-specific location of the DRT as demonstrated by DTI (direct targeting) and correlated with traditional atlas-based measurements for thalamic ventral intermediate nucleus (Vim) lesioning (indirect targeting). Fiber tracts were displayed three-dimensionally during the procedure and used in conjunction with clinical signs of tremor control for fine correction of the ablation site. Immediately following the conclusion of the procedure, the MRgFUS head frame was removed and patients were placed in a 32-channel MRI head coil for follow-up DTI and anatomical MRI sequences.

RESULTS

All patients had excellent postoperative tremor control and successful pre- and postprocedural DTI fiber tracking of the corticospinal tract, medial lemniscus, and DRT. Immediate postprocedure DTI failed to track the DRT ipsilateral to the lesion site with a preserved contralateral DRT, coincident with substantial resolution of contralateral tremor.

CONCLUSIONS

DTI can reliably identify the optimal ablation target and demonstrates tract disruption on immediate postprocedural imaging. A clinical improvement of ET was observed immediately following the procedure, correlating with DRT disruption and suggesting that interruption of the DRT is a consequence of clinically successful MRgFUS thalamotomy. These findings may have utility for both MRgFUS procedure planning in surgically naive patients and retreatment of patients who have previously undergone unsuccessful thalamic Vim lesioning.

Neurosurgery in East Africa: Foundations

This article is the first in a series of 3 articles that seek to provide readers with an understanding of the development of neurosurgery in East Africa (Foundations), the challenges that arise in providing neurosurgical care in developing countries (Challenges), and an overview of traditional and novel approaches to overcoming these challenges to improve healthcare in the region (Innovations). We review the history and evolution of neurosurgery as a clinical specialty in East Africa. We also review Kenya, Uganda, and Tanzania in some detail and highlight contributions of individuals and local and regional organizations that helped to develop and shape neurosurgical care in East Africa. Neurosurgery has developed steadily as advanced techniques have been adopted by local surgeons who trained abroad, and foreign surgeons who have dedicated part of their careers in local hospitals. New medical schools and surgical training programs have been established through regional and international partnerships, and the era of regional specialty surgical training has just begun. As more surgical specialists complete training, a comprehensive estimation of disease burden facing the neurosurgical field is important. We present an overview with specific reference to neurotrauma and neural tube defects, both of which are of epidemiologic importance as they gain not only greater recognition, but increased diagnoses and demands for treatment. Neurosurgery in East Africa is poised to blossom as it seeks to address the growing needs of a growing subspecialty.

Neurosurgery in East Africa: Innovations

In the last 10 years, considerable work has been done to promote and improve neurosurgical care in East Africa with the development of national training programs, expansion of hospitals and creation of new institutions, and the foundation of epidemiologic and cost-effectiveness research. Many of the results have been accomplished through collaboration with partners from abroad. This article is the third in a series of articles that seek to provide readers with an understanding of the development of neurosurgery in East Africa (Foundations), the challenges that arise in providing neurosurgical care in developing countries (Challenges), and an overview of traditional and novel approaches to overcoming these challenges to improve healthcare in the region (Innovations). In this article, we describe the ongoing programs active in East Africa and their current priorities, and we outline lessons learned and what is required to create self-sustained neurosurgical service.

Do craniopharyngioma molecular signatures correlate with clinical characteristics?

OBJECTIVE

Exome sequencing studies have recently demonstrated that papillary craniopharyngiomas (PCPs) and adamantinomatous craniopharyngiomas (ACPs) have distinct genetic origins, each primarily driven by mutually exclusive alterations: either BRAF (V600E), observed in 95% of PCPs, or CTNNB1, observed in 75%–96% of ACPs. How the presence of these molecular signatures, or their absence, correlates with clinical, radiographic, and outcome variables is unknown.

METHODS

The pathology records for patients who underwent surgery for craniopharyngiomas between May 2000 and March 2015 at Weill Cornell Medical College were reviewed. Craniopharyngiomas were identified and classified as PCP or ACP. Patients were placed into 1 of 3 groups based on their genomic mutations: BRAF mutation only, CTNNB1 mutation only, and tumors with neither of these mutations detected (not detected [ND]). Demographic, radiological, and clinical variables were collected, and their correlation with each genomic group was tested.

RESULTS

Histology correlated strongly with mutation group. All BRAF tumors with mutations were PCPs, and all CTNNB1 with mutations and ND tumors were ACPs. Preoperative and postoperative clinical symptoms and radiographic features did not correlate with any mutation group. There was a statistically significant relationship (p = 0.0323) between the age group (pediatric vs adult) and the mutation groups. The ND group tumors were more likely to involve the sella (p = 0.0065).

CONCLUSIONS

The mutation signature in craniopharyngioma is highly predictive of histology. The subgroup of tumors in which these 2 mutations are not detected is more likely to occur in children, be located in the sella, and be of ACP histology.

The rectus capitis lateralis and the condylar triangle: important landmarks in posterior and lateral approaches to the jugular foramen

OBJECTIVE

The rectus capitis lateralis (RCL) is a small posterior cervical muscle that originates from the transverse process of C-1 and inserts onto the jugular process of the occipital bone. The authors describe the RCL and its anatomical relationships, and discuss its utility as a surgical landmark for safe exposure of the jugular foramen in extended or combined skull base approaches. In addition, the condylar triangle is defined as a landmark for localizing the vertebral artery (VA) and occipital condyle.

METHODS

Four cadaveric heads (8 sides) were used to perform far-lateral, extended far-lateral, combined transmastoid infralabyrinthine transcervical, and combined far-lateral transmastoid infralabyrinthine transcervical approaches to the jugular foramen. On each side, the RCL was dissected, and its musculoskeletal, vascular, and neural relationships were examined.

RESULTS

The RCL lies directly posterior to the internal jugular vein—only separated by the carotid sheath and in some cases cranial nerve (CN) XI. The occipital artery travels between the RCL and the posterior belly of the digastric muscle, and the VA passes medially to the RCL as it exits the C-1 foramen transversarium and courses posteriorly toward its dural entrance. CNs IX–XI exit the jugular foramen directly anterior to the RCL. To provide a landmark for identification of the occipital condyle and the extradural VA without exposure of the suboccipital triangle, the authors propose and define a condylar triangle that is formed by the RCL anteriorly, the superior oblique posteriorly, and the occipital bone superiorly.

CONCLUSIONS

The RCL is an important surgical landmark that allows for early identification of the critical neurovascular structures when approaching the jugular foramen, especially in the presence of anatomically displacing tumors. The condylar triangle is a novel and useful landmark for identifying the terminal segment of the hypoglossal canal as well as the superior aspect of the VA at its exit from the C-1 foramen transversarium, without performing a far-lateral exposure.

Severe Traumatic Brain Injury at a Tertiary Referral Center in Tanzania: Epidemiology and Adherence to Brain Trauma Foundation Guidelines

BACKGROUND

Severe traumatic brain injury (TBI) is a major cause of death and disability worldwide. Prospective TBI data from sub-Saharan Africa are sparse. This study examines epidemiology and explores management of patients with severe TBI and adherence to Brain Trauma Foundation Guidelines at a tertiary care referral hospital in Tanzania.

METHODS

Patients with severe TBI hospitalized at Bugando Medical Centre were recorded in a prospective registry including epidemiologic, clinical, treatment, and outcome data.

RESULTS

Between September 2013 and October 2015, 371 patients with TBI were admitted; 33% (115/371) had severe TBI. Mean age was 32.0 years ± 20.1, and most patients were male (80.0%). Vehicular injuries were the most common cause of injury (65.2%). Approximately half of the patients (47.8%) were hospitalized on the day of injury. Computed tomography of the brain was performed in 49.6% of patients, and 58.3% were admitted to the intensive care unit. Continuous arterial blood pressure monitoring and intracranial pressure monitoring were not performed in any patient. Of patients with severe TBI, 38.3% received hyperosmolar therapy, and 35.7% underwent craniotomy. The 2-week mortality was 34.8%.

CONCLUSIONS

Mortality of patients with severe TBI at Bugando Medical Centre, Tanzania, is approximately twice that in high-income countries. Intensive care unit care, computed tomography imaging, and continuous arterial blood pressure and intracranial pressure monitoring are underused or unavailable in the tertiary referral hospital setting. Improving outcomes after severe TBI will require concerted investment in prehospital care and improvement in availability of intensive care unit resources, computed tomography, and expertise in multidisciplinary care.

Abstract 191: Selective Frontal Lobe Metabolic Dysfunction After Sub-arachnoid Hemorrhage

Aneurysmal SAH results in high morbidity. Patients who make a good neurological recovery report significant neuropsychological impairment such as loss of motivation, interests, and concentration, all of which are commonly associated with frontal lobe dysfunction. We hypothesize that subclinical frontal lobe injury occurs in neurologically intact SAH patients and may be identified by measuring brain energy metabolism using regional N-acetyl aspartate (NAA) as an imaging marker of neuronal integrity and mitochondrial function, and CSF lactate, as a marker of anaerobic metabolism. We utilized MR Spectroscopy (MRS) to measure regional NAA in SAH patients who had suffered neither cerebral infarction nor neurological deficits. Only patients who underwent endovascular aneurysm coiling were included. Measurements were made in frontal, temporal, occipital lobes, lateral ventricles, and averaged in each hemisphere from 3 slices. Matching ROIs were placed on the most proximate CT perfusion maps to measure corresponding rCBF. MR spectra were compared to controls from our data library (7 subjects) and to rCBF. Average age was 58 years, Hunt Hess score was 2.43±1.09, modified Fisher score was 2.79±1.05. 3 patients had DCI and none had cerebral infarction. Median GCS at discharge was 15. MRS was done at 9.93±7.73 days from admission. 1 patient had no MRS data, 3 patients had no CT perfusion. SAH patients demonstrated significantly reduced NAA/RMS in frontal lobes (16.18±4.96 vs. 20.93±5.56, p=0.042) but not in temporal (16.49±4.37 vs. 19.37±4.38, p=0.09) or occipital lobes (20.62±4.50 vs. 21.05±4.23, p=0.41). CSF lactate was significantly higher in SAH patients (7.74±2.27 vs. 4.02±0.76, p=0.001). NAA/RMS did not correlate with CBF in pooled data (R 2 =0.02, p=0.40) or in frontal lobe rCBF (R 2 =0.001, p=0.92); nor with CSF lactate (R 2 =0.02, p=0.53). Total frontal lobe NAA is selectively reduced and CSF lactate is elevated in neurologically intact survivors after SAH. This preliminary data is suggestive of energy depletion and subclinical brain injury, which appears to be independent of cerebral blood flow. In addition to validating this pilot data, we will study the association with cognitive impairment in these patients.

The role of alternative anastomosis sites in occipital artery–posterior inferior cerebellar artery bypass in the absence of the caudal loop using the far-lateral approach

OBJECTIVE

Occipital artery–posterior inferior cerebellar artery (OA-PICA) bypass is a technically challenging procedure for posterior fossa revascularization. The caudal loop of the PICA is considered the optimal site for OA-PICA anastomosis, however its absence can increase the technical difficulty associated with this procedure. The use of the far-lateral approach for accessing alternative anastomosis sites in OA-PICA bypass in patients with absent or unavailable caudal loops of PICA is evaluated.

METHODS

A morphometric analysis of OA-PICA bypass with anastomosis on each segment of the PICA was performed on 5 cadaveric specimens through the conventional midline foramen magnum and far-lateral approaches. The difficulty level associated with anastomoses at each segment was qualitatively assessed in each approach for exposure and maneuverability by multiple surgeons. A series of 8 patients who underwent OA-PICA bypass for hemodynamic ischemia or ruptured dissecting posterior fossa aneurysms are additionally reviewed and described, and the clinical significance of the caudal loop of PICA is discussed.

RESULTS

Anastomosis on the caudal loop could be performed more superficially than on any other segment (p < 0.001). A far-lateral approach up to the medial border of the posterior condylar canal provided a 13.5 ± 2.2–mm wider corridor than the conventional midline foramen magnum approach, facilitating access to alternative anastomosis sites. The far-lateral approach was successfully used for OA-PICA bypass in 3 clinical cases whose caudal loops were absent, whereas the midline foramen magnum approach provided sufficient exposure for caudal loop bypass in the remaining 5 cases.

CONCLUSIONS

The absence of the caudal loop of the PICA is a major contributing factor to the technical difficulty of OA-PICA bypass. The far-lateral approach is a useful surgical option for OA-PICA bypass when the caudal loop of the PICA is unavailable.

Cesium-131 brachytherapy for recurrent brain metastases: durable salvage treatment for previously irradiated metastatic disease

OBJECTIVE Managing patients whose intraparenchymal brain metastases recur after radiotherapy remains a challenge. Intraoperative cesium-131 (Cs-131) brachytherapy performed at the time of neurosurgical resection may represent an excellent salvage treatment option. The authors evaluated the outcomes of this novel treatment with permanent intraoperative Cs-131 brachytherapy. METHODS Thirteen patients with 15 metastases to the brain that recurred after stereotactic radiosurgery and/or whole brain radiotherapy were treated between 2010 and 2015. Stranded Cs-131 seeds were placed as a permanent volume implant. Prescription dose was 80 Gy at 5-mm depth from the resection cavity surface. The primary end point was resection cavity freedom from progression (FFP). Resection cavity freedom from progression (FFP), regional FFP, distant FFP, median survival, overall survival (OS), and toxicity were assessed. RESULTS The median duration of follow-up after salvage treatment was 5 months (range 0.5-18 months). The patients' median age was 64 years (range 51-74 years). The median resected tumor diameter was 2.9 cm (range 1.0-5.6 cm). The median number of seeds implanted was 19 (range 10-40), with a median activity per seed of 2.25 U (range 1.98-3.01 U) and median total activity of 39.6 U (range 20.0-95.2 U). The 1-year actuarial local FFP was 83.3%. The median OS was 7 months, and 1-year OS was 24.7%. Complications included infection (3), pseudomeningocele (1), seizure (1), and asymptomatic radionecrosis (RN) (1). CONCLUSIONS After failure of prior irradiation of brain metastases, re-irradiation with intraoperative Cs-131 brachytherapy implants provides durable local control and limits the risk of RN. The authors' initial experience demonstrates that this treatment approach is well tolerated and safe for patients with previously irradiated tumors after failure of more than 1 radiotherapy regimen and that it results in excellent response rates and minimal toxicity.

Vincent du Vigneaud: following the sulfur trail to the discovery of the hormones of the posterior pituitary gland at Cornell Medical College

In 1955, Vincent du Vigneaud (1901–1978), the chairman of the Department of Biochemistry at Cornell University Medical College, was awarded the Nobel Prize for Chemistry for his research on insulin and for the first synthesis of the posterior pituitary hormones—oxytocin and vasopressin. His tremendous contribution to organic chemistry, which began as an interest in sulfur-containing compounds, paved the way for a better understanding of the pituitary gland and for the development of diagnostic and therapeutic tools for diseases of the pituitary. His seminal research continues to impact neurologists, endocrinologists, and neurosurgeons, and enables them to treat patients who had no alternatives prior to du Vigneaud’s breakthroughs in peptide structure and synthesis. The ability of neurosurgeons to aggressively operate on parasellar pathology was directly impacted and related to the ability to replace these hormones after surgery. The authors review the life and career of Vincent du Vigneaud, his groundbreaking discoveries, and his legacy of the understanding and treatment of the pituitary gland in health and disease.

Postoperative imaging for detection of recurrent arteriovenous malformations in children

OBJECT The optimal method for detecting recurrent arteriovenous malformations (AVMs) in children is unknown. An inherent preference exists for MR angiography (MRA) surveillance rather than arteriography. The validity of this strategy is uncertain. METHODS A retrospective chart review was performed on pediatric patients treated for cerebral AVMs at a single institution from 1998 to 2012. Patients with complete obliteration of the AVM nidus after treatment and more than 12 months of follow-up were included in the analysis. Data collection focused on recurrence rates, associated risk factors, and surveillance methods. RESULTS A total of 45 patients with a mean age of 11.7 years (range 0.5-18 years) were treated for AVMs via surgical, endovascular, radiosurgical, or combined approaches. Total AVM obliteration on posttreatment digital subtraction angiography (DSA) was confirmed in 27 patients, of whom the 20 with more than 12 months of follow-up were included in subsequent analysis. The mean follow-up duration in this cohort was 5.75 years (median 5.53 years, range 1.11-10.64 years). Recurrence occurred in 3 of 20 patients (15%). Two recurrences were detected by surveillance DSA and 1 at the time of rehemorrhage. No recurrences were detected by MRA. Median time to recurrence was 33.6 months (range 19-71 months). Two patients (10%) underwent follow-up DSA, 5 (25%) had DSA and MRI/MRA, 9 (45%) had MRI/MRA only, 1 (5%) had CT angiography only, and 3 (15%) had no imaging within the first 3 years of follow-up. After 5 years posttreatment, 2 patients (10%) were followed with MRI/MRA only, 2 (10%) with DSA only, and 10 (50%) with continued DSA and MRI/MRA. CONCLUSIONS AVM recurrence in children occurred at a median of 33.6 months, when MRA was more commonly used for surveillance, but failed to detect any recurrences. A recurrence rate of 15% may be an underestimate given the reliance on surveillance MRA over angiography. A new surveillance strategy is proposed, taking into account exposure to diagnostic radiation and the potential for catastrophic rehemorrhage.

Selective Patch Angioplasty and Intraoperative Shunting in Carotid Endarterectomy: A Single-Center Review of 141 Procedures

Objective: Open surgical treatment of carotid artery stenosis, namely, carotid endarterectomy (CEA), has evolved since its inception in 1953. Despite improvements in the treatment of carotid occlusive disease through technological and surgical innovations, the use of patch grafting in CEA’s remains controversial. We evaluate the durability of the primary closure and the safety of selective shunting during carotid endarterectomy (CEA) as determined by intraoperative EEG and postoperative outcomes.

Methods: A consecutive series of CEA’s performed by the senior author at a single academic medical center from 2001 to 2012 were reviewed. All cases were performed under continuous intraoperative electroencephalography (EEG). Patch angioplasty was used in cases where there was tortuosity of the vessel within the region of the endarterectomy and narrow vessel diameter at the distal end of the arteriotomy. Shunting was used when intraoperative EEG showed a > 50% reduction in a waveform in any lead. Patients were evaluated for restenosis via imaging or ultrasound at six months and subsequently annual follow-up.

Results: One hundred and forty-one CEA’s were performed on 132 (76 male, 56 female) patients with an average age of 71 years (range: 40–95 years). Four (3%) cases required patch angioplasty and three (2%) required intraoperative shunts. The cross-clamp time ranged from 22 to 74 minutes, and the duration increased with the use of shunts and patches. Complications were rare and included recurrent stenosis (n=2), postoperative transient ischemic attack (n=1), ischemic stroke in (n=1), temporary hypoglossal nerve weakness (n=2), temporary marginal mandibular nerve weakness (n=6), and neck hematoma (n=1).

Conclusion: Intraoperative EEG data suggests that primary closure and selective shunting in CEA can result in outcomes comparable with routine patch angioplasty and shunting.

Surgical Technique and Clinically Relevant Resection Cavity Dynamics Following Implantation of Cesium-131 (Cs-131) Brachytherapy in Patients With Brain Metastases

BACKGROUND

Cesium-131 (Cs-131) brachytherapy is used to reduce local recurrence of resected brain metastases. In order to ensure dose homogeneity and reduce risk of radiation necrosis, inter-seed distance and cavity volume must remain stable during delivery.

OBJECTIVE

To investigate the efficacy of the "seeds-on-a-string" technique with intracavitary fibrin glue in achieving cavity volume stability.

METHODS

We placed intra-operative Cs-131 brachytherapy in 30 cavities post-resection of brain metastases. Seeds-on-a-string were placed like barrel staves within the cavity with fibrin glue. Serial MRI imaging occurred post-operatively. Pre-operative tumor volumes were compared with post-operative cavity volumes to evaluate volume stability. Thirty patients who underwent post-resective stereotactic radiosurgery (SRS) were used as a control group for volumetric comparison.

RESULTS

Cs-131 and SRS patients exhibited consistent cavity shrinkage over the median 110-day follow-up (p<.001), with total median shrinkage of 56.5% (Cs-131) and 84.8% (SRS). During the first month when ~88% of Cs-131 dosage is delivered, however, there was non-significant volume decrease in the Cs-131 group (median 22.0%; p=.063), while SRS patients showed significantly more shrinkage (46.7%; p=.042). No events of radiation necrosis occurred in either group.

CONCLUSION

Cs-131 patients exhibited significantly less cavity shrinkage than SRS patients during the first critical month with 88% Cs-131 dose delivery. This significant difference in shrinkage suggests that the intracavitary seeds-on-a-string technique facilitates increased cavity stability, promoting more homogenous dose delivery.