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SummaryBackgroundThe global launch of ChatGPT on November 30, 2022 has sparked widespread public interest in large language models (LLMs), and interest in the medical community is growing. Indeed, recent preprints on medRxiv have examined ChatGPT and GPT-3 in the context of standardized exams, such as the United States Medical Licensing Examination. These studies demonstrate modest performance relative to national averages. In this work, we enhance OpenAI’s GPT-3 model through zero-shot learning, anticipating that it outperforms experienced neurosurgeons in written question-answer tasks for common clinical and surgical questions on vestibular schwannoma. We aimed to address LLM accountability by including in-text citations and references to the responses provided by GPT-3.MethodsThe analysis involved (i) creating a dataset through web scraping, (ii) developing a chat-based platform called neuroGPT-X, (iii) enlisting expert neurosurgeons across international centers to create and answer questions and evaluate responses, and (iv) analyzing the evaluation results on the management of vestibular schwannoma. The survey had a blinded and unblinded phase. In the blinded phase, a neurosurgeon with 30+ years of experience curated 15 questions regarding common clinical and surgical contexts of vestibular schwannoma. Then, four neurosurgeons, ChatGPT (January 30, 2023 model, akanaiveGPT), and a context-enriched GPT model independently provided their responses. Three experienced neurosurgeons blindly evaluated the responses for accuracy, coherence, relevance, thoroughness, speed, and overall rating. Then, all seven neurosurgeons were unblinded to all responses and provided their thoughts on the potential of expert LLMs in the clinical setting.FindingsBoth the naive and content-enriched GPT models provided faster responses to the standardized question set (p0.999) or performance across the aforementioned domains (p>0.999). 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. Further, we developed neuroGPT-X, a chat-based platform designed to provide point-of-care clinical support and mitigate 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.InterpretationA context-enriched GPT model provided non-inferior responses compared to experienced neurosurgeons in generating written responses to a complex neurosurgical problem for which evidence-based consensus for management is lacking. We show that context enrichment of LLMs is well-suited to transform clinical practice by providing subspecialty-level answers to clinical questions in an accountable manner.Research in ContextEvidence before this studyWe searched PubMed for “(vestibular schwannoma OR acoustic schwannoma) AND (GPT-3 OR Generative Pretrained Transformer OR large language model)” with no filters and identified no relevant articles. We then searched PubMed using the string “(subspecialty OR neurosurgery OR physician) AND (GPT-3 OR Generative Pretrained Transformer OR large language model) AND (fine-tuning OR context enrichment)” with no filters and identified three studies. One study noted that domain-specific knowledge enhanced pre-trained language models.Added value of this studyTo our knowledge, this is the first study to show the non-inferiority of a context-enriched LLM in a question-answer task on common clinical and surgical questions compared to experienced neurosurgeons worldwide, determined by their neurosurgical colleagues. Furthermore, we developed the first online platform incorporating an LLM, chat memory, in-text citations, and references regarding comprehensive vestibular schwannoma management. To assess the model’s performance, a neurosurgeon with 30+ years of experience managing patients with vestibular schwannoma curated 15 questions to the model, ChatGPT, and four international expert neurosurgeons. A separate, blinded group of three expert neurosurgeons assessed these answers for accuracy, coherence, relevance, thoroughness, speed, and overall rating. This study demonstrated the capability of context-enriched LLMs as point-of-care informational aids. Importantly, all expert surgeons raised questions regarding the nuances and role of human experience and intuition that GPT may not capture in generating opinions or recommendations.Implications of all the available evidenceThe present study, with its subspecialist-level performance and interpretable results, suggests that context-enriched LLMs show promise as a point-of-care medical resource. Evaluations from experienced neurosurgeons showed that a context-enriched GPT model was rated similarly to neurosurgeon responses across evaluation domains in this study. This work serves as a springboard for expanding this tool into more medical specialties, incorporating evidence-based clinical information, and developing expert-level dialogue surrounding LLMs in healthcare.

Background Open surgery has traditionally been preferred for the management of bifurcation middle cerebral artery (MCA) aneurysms. Flow diverting stents present a novel endovascular strategy for aneurysm treatment. Objective To add to the limited literature describing the outcomes and complications in the use of flow diverters for the treatment of these complex aneurysms. Methods This is a multicenter retrospective review of MCA bifurcation aneurysms undergoing flow diversion. We assessed post-treatment radiological outcomes and both thromboembolic and hemorrhagic complications. Results We reviewed the outcomes of 54 aneurysms treated with flow diversion. Four (7.4%) of the aneurysms had a history of rupture (3 remote and 1 acute). Fourteen (25.9%) of the aneurysms already underwent either open surgery or coiling prior to flow diversion. A total of 36 out of the 45 aneurysms (80%) with available follow-up data had adequate aneurysm occlusion with a median follow-up time of 12 mo. There were no hemorrhagic complications but 16.7% (9/54) had thromboembolic complications. Conclusion Flow diverting stents may be a viable option for the endovascular treatment of complex bifurcation MCA aneurysms. However, compared to published series on the open surgical treatment of this subset of aneurysms, flow diversion has inferior outcomes and are associated with a higher rate of complications.

OBJECTIVEDespite efforts toward achieving gender equality in clinical trial enrollment, females are often underrepresented, and gender-specific data analysis is often unavailable. Identifying and reducing gender bias in medical decision-making and outcome reporting may facilitate equitable healthcare delivery. Gender disparity in the utilization of surgical therapy has been exemplified in the orthopedic literature through studies of total joint arthroplasty. A paucity of literature is available to guide the management of lumbar degenerative disease, which stratifies on the basis of demographic factors. The objective of this study was to systematically map and synthesize the adult surgical literature regarding gender differences in pre- and postoperative patient-reported clinical assessment scores for patients with lumbar degenerative disease (disc degeneration, disc herniation, spondylolisthesis, and spinal canal stenosis).METHODSA systematic scoping review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR) guidelines. MEDLINE, Embase, and the Cochrane Registry of Controlled Trials were searched from inception to September 2018. Study characteristics including patient demographics, diagnoses, procedures, and pre- and postoperative clinical assessment scores (pain, disability, and health-related quality of life [HRQoL]) were collected.RESULTSThirty articles were identified, accounting for 32,951 patients. Six studies accounted for 84% of patients; 5 of the 6 studies were published by European groups. The most common lumbar degenerative conditions were disc herniation (59.0%), disc degeneration (20.3%), and spinal canal stenosis (15.9%). The majority of studies reported worse preoperative pain (93.3%), disability (81.3%), and HRQoL (75%) among females. The remainder reported equivalent preoperative scores between males and females. The majority of studies (63.3%) did not report preoperative duration of symptoms, and this represents a limitation of the data. Eighty percent of studies found that females had worse absolute postoperative scores in at least one outcome category (pain, disability, or HRQoL). The remainder reported equivalent absolute postoperative scores between males and females. Seventy-three percent of studies reported either an equivalent or greater interval change for females.CONCLUSIONSFemale patients undergoing surgery for lumbar degenerative disease (disc degeneration, disc herniation, spondylolisthesis, and spinal canal stenosis) have worse absolute preoperative pain, disability, and HRQoL. Following surgery, females have worse absolute pain, disability, and HRQoL, but demonstrate an equal or greater interval change compared to males. Further studies should examine gender differences in preoperative workup and clinical course.

OBJECTIVEThe prevalence of trigeminal neuralgia (TN) in patients with multiple sclerosis (MS-TN) is higher than in the general population (idiopathic TN [ITN]). Glycerol rhizotomy (GR) is a percutaneous lesioning surgery commonly performed for the treatment of medically refractory TN. While treatment for acute pain relief is excellent, long-term pain relief is poorer. The object of this study was to assess the efficacy of percutaneous retrogasserian GR for the treatment of MS-TN versus ITN.METHODSA retrospective chart review was performed, identifying 219 patients who had undergone 401 GR procedures from 1983 to 2018 at a single academic institution. All patients were diagnosed with medically refractory MS-TN (182 procedures) or ITN (219 procedures). The primary outcome measures of interest were immediate pain relief and time to pain recurrence following initial and repeat GR procedures. Secondary outcomes included medication usage and presence of periprocedural hypesthesia.RESULTSThe initial pain-free response rate was similar between groups (p = 0.726): MS-TN initial GR 89.6%; MS-TN repeat GR 91.9%; ITN initial GR 89.6%; ITN repeat GR 87.0%. The median time to recurrence after initial GR was similar between MS-TN (2.7 ± 1.3 years) and ITN (2.1 ± 0.6 years) patients (p = 0.87). However, there was a statistically significant difference in the time to recurrence after repeat GR between MS-TN (2.3 ± 0.5 years) and ITN patients (1.2 ± 0.2 years; p < 0.05). The presence of periprocedural hypesthesia was highly predictive of pain-free survival (p < 0.01).CONCLUSIONSPatients with MS-TN achieve meaningful pain relief following GR, with an efficacy comparable to that following GR in patients with ITN. Initial and subsequent GR procedures are equally efficacious.

Radial artery access has experienced increasing adoption and rapid expansion of indications for neurointerventional procedures. This access is an attractive neurointervention route to be considered, with many advantages over the traditional femoral access in terms of ease of vasculature navigation and decreased risk of complications such as significant bleeding. Although a promising technique for neurointerventional procedures, there are inherent and unique considerations as well as potential complications involved. The following case report highlights some of these vital concepts associated with radial artery access, including appropriate patient selection as well as assessment of arterial size in the context of neurointerventional techniques. Early identification of complications such as arterial injury and compartment syndrome, with an emphasis on appropriate draping and inter-procedure monitoring, is discussed as well as approaches for subsequent management. Finally, the issue of radiation safety in this emerging technique is considered. These concepts are critical for the successful use and the continued growth of radial artery access for neurointervention procedures.

Background: Aneurysmal persistence after flow diversion (FD) occurs in 5% to 25% of aneurysms, which may necessitate retreatment. There are limited data on safety/efficacy of repeat FD—a frequently utilized strategy in such cases. Methods: A series of consecutive patients undergoing FD retreatment from 15 centers were reviewed (2011–2019), with inclusion criteria of repeat FD for the same aneurysm at least 6 months after initial treatment, with minimum of 6 months post-retreatment imaging. The primary outcome was aneurysmal occlusion, and secondary outcome was safety. A multivariable logistic regression model was constructed to identify predictors of incomplete occlusion (90%–99% and Results: Ninety-five patients (median age, 57 years; 81% women) harboring 95 aneurysms underwent 198 treatment procedures. Majority of aneurysms were unruptured (87.4%), saccular (74.7%), and located in the internal carotid artery (79%; median size, 9 mm). Median elapsed time between the first and second treatment was 12.2 months. Last available follow-up was at median 12.8 months after retreatment, and median 30.6 months after the initial treatment, showing complete occlusion in 46.2% and near-complete occlusion (90%–99%) in 20.4% of aneurysms. There was no difference in ischemic complications following initial treatment and retreatment (4.2% versus 4.2%; P >0.99). On multivariable regression, fusiform morphology had higher nonocclusion odds after retreatment (odds ratio [OR], 7.2 [95% CI, 1.97–20.8]). Family history of aneurysms was associated with lower odds of nonocclusion (OR, 0.18 [95% CI, 0.04–0.78]). Likewise, positive smoking history was associated with lower odds of nonocclusion (OR, 0.29 [95% CI, 0.1–0.86]). History of hypertension trended toward incomplete occlusion (OR, 3.10 [95% CI, 0.98–6.3]), similar to incorporated branch into aneurysms (OR, 2.78 [95% CI, 0.98–6.8]). Conclusions: Repeat FD for persistent aneurysms carries a reasonable success/safety profile. Satisfactory occlusion (100% and 90%–99% occlusion) was encountered in two-thirds of patients, with similar complications between the initial and subsequent retreatments. Fusiform morphology was the strongest predictor of retreatment failure.

Background:Aneurysmal subarachnoid haemorrhage (aSAH) is associated with significant morbidity and mortality. The International Subarachnoid Aneurysm Trial (ISAT) reported reduced morbidity in patients treated with endovascular coiling versus surgical clipping. However, recent studies suggest that there is no significant difference in clinical outcomes. This study examines the outcomes of either technique for treating aSAH during the 15 years post-ISAT at a Canadian quaternary centre.Methods:We reviewed prospectively collected data of patients admitted with aSAH from January 2002 to December 2017. Glasgow Outcome Scale (GOS) was compared at discharge, 6 months and 12 months’ follow-up using univariate and multivariable ordinal logistic regression. Post-operative complications were assessed using binary logistic regression.Results:Two-hundred and eighty-seven patients were treated with coiling and 95 patients with clipping. The mean age of clipped patients was significantly younger, and hypertension was significantly commoner in coiled patients. A greater proportion of coiled aneurysms were located in the posterior circulation. No difference in the odds of having a favourable GOS was seen between patients who were clipped versus coiled at any of follow-up time points on univariate or multivariable analysis. In both treatment groups, patient recovery to independence (GOS 4–5) was seen from discharge to 6 months, but not from 6 to 12 months’ follow-up, without difference between clipping and coiling.Conclusion:These real-world findings suggest clipping remains an effective and important treatment option for patients with aSAH who do not meet ISAT inclusion criteria. The results can assist in clinical decision-making processes and understanding of the natural recovery progression of aSAH.

Background Aneurysmal persistence after flow-diversion (FD) occurs in 5–25% of aneurysms which might necessitate further treatment. A frequently used retreatment paradigm utilizes the deployment of another flow-diverting device (FDD) in a telescoping fashion within the existing device. There are no current data evaluating this strategy. Methods A retrospective review of patients undergoing FD retreatment from 15 centers was performed, with inclusion criteria being repeat FD occurring for the same aneurysm at least 6 months after initial treatment, with minimum of 6 months of imaging follow-up after retreatment. Primary outcome was aneurysmal occlusion, and secondary outcomes were safety and complications. A multivariable logistic regression model was constructed to identify predictors of persistence/occlusion after retreatment. Comparative Kaplan-Meier curves were developed to assess the effect of early (6–12 months since initial treatment) vs late retreatment (>12 months since initial treatment) on the cumulative incidence of aneurysm occlusion over time. Results Ninety-five patients (median age 57, 81% females) harboring 95 aneurysms underwent 198 treatment procedures. In our cohort, 87.4% of aneurysms were unruptured; 74.7% were saccular and 79% were located in the internal carotid artery (median maximal diameter 9-mm), with 87 patients treated twice and 8 patients treated thrice. Median elapsed-time between first and second treatment was 12.2 months. Last available follow-up was performed at median of 12.8 months after retreatment, and median of 30.6 months after initial treatment, showing complete occlusion in 46.2%, and near-complete occlusion (90–99%) in 20.4% of aneurysms. No difference in ischemic complications following initial treatment and retreatment (4.2% vs 4.2; p>0.99). On multivariable logistic regression, fusiform morphology was associated with higher odds of non-occlusion after retreatment (OR 7.2; p=0.003), with history of hypertension and incorporated branch into aneurysms trending toward incomplete occlusion (p=0.055 and p=0.054; respectively). Family history of aneurysms and positive smoking history were associated with higher odds of complete occlusion (p=0.019 and p=0.026; respectively). Kaplan-Meier curves comparative estimators showed no significant difference in time-to-occlusion between the two groups (log rank test, p=0.48). Conclusion Repeat flow diversion for persistent aneurysms is safe and effective. Fusiform morphology is the strongest predictor of aneurysmal persistence after repeat flow diversion. Disclosures M. Salem: None. A. Sweid: None. A. Kuhn: None. A. Dmytriw: None. S. Gomez-Paz: None. G. Maragkos: None. M. Waqas: None. C. Parra-Farinas: None. A. Salehani: None. N. Adeeb: None. P. Brouwer: None. G. Pickett: None. M. Ghuman: None. V. Yang: None. A. Weill: None. C. Cognard: None. L. Renieri: None. P. Kan: None. N. Limbucci: None. V. Mendes Pereira: None. M. Harrigan: None. A. Puri: None. E. Levy: None. J. Moore: None. C. Ogilvy: None. T. Marotta: None. P. Jabbour: None. A. Thomas: None.

Introduction: We sought to train and validate an automated machine learning algorithm for ICH segmentation and volume calculation using multicenter data. Methods: An open-source 3D deep machine learning algorithm “DeepMedic” was trained using manually segmented ICH from 208 CT scans (129 patients) from the multicenter PREDICT study. The algorithm was then validated with 125 manually segmented CT scans (48 patients) from the SPOTLIGHT study. Manual segmentation was performed with Quantomo semi-automated software. ABC/2 was measured for all studies by two neuroradiologists. Accuracy of DeepMedic segmentation was assessed using the Dice similarity coefficient. Analysis was stratified by presence of IVH. Intraclass correlation (ICC) with 95% confidence intervals (CI) assessed agreement between manual vs. DeepMedic segmentation volume; and manual segmentation and ABC/2 volume. Bland-Altman charts were analyzed for ABC/2 and DeepMedic vs. manual segmentation volumes. Results: DeepMedic demonstrated high segmentation accuracy in the training cohort (median Dice 0.96; IQR 0.95 - 0.97) and in the validation cohort (median Dice 0.91; IQR 0.86 - 0.94). Dice coefficients were not significantly different between patients with IVH in the training cohort; however was significantly worse in the validation cohort in patients with IVH (Wilcoxon p Conclusion: ICH machine learning segmentation with DeepMedic is feasible and accurate; and demonstrates greater agreement with manual segmentation compared to ABC/2 volumes. Accuracy of the machine learning algorithm however is limited in patients with IVH.

A previously healthy right-handed 39-year-old man presented to the emergency department with a 5-month history of self-described personality changes, including anger issues. He had a 6-day history of expressive dysphasia, word substitution and slurring of speech. His medical history was notable only

Background The flow diverting stent is a new and expansive tool in the endovascular therapy of complex intracranial aneurysms. We present our experience using SILK flow diverter (SFD) in patients with complex intracranial aneurysms, and a cost analysis. Methods Between September 2010 and May 2012, 19 consecutive patients with 29 complex intracranial aneurysms were treated with SFD without the adjunctive use of coils. We retrospectively evaluated the technical aspects, thromboembolic events, adjunctive therapies, and short term results in patients with complex intracranial aneurysms treated with SFD. A cost analysis of patients who were treated with SFD was performed and compared with similar sized aneurysms coiled with stent assisted coiling. Results The primary technical success rate was 100%. An adjunctive device was required in two of our patients. The technique related complication rate and the 30 day mortality and morbidity rates were 5% (1/20) and 10% (2/20), respectively. We had a total of 263 patient months of clinical and 166 patient months of imaging follow-up. Follow-up imaging revealed two asymptomatic occlusions of the parent artery. Complete occlusion of the aneurysm with fully patent parent artery was observed in 59% of patients where follow-up images were available. The cost analysis showed that the mean cost of treatment with SFD was significantly cheaper compared with the presumed cost of stent assisted coiling (p Conclusions The SFD provides a very feasible, efficient, relatively safe, and cost effective method to treat complex intracranial aneurysms without the use of adjunct coiling.

Objective and Design:There is controversy among neurosurgeons regarding whether double burr hole craniostomy (DBHC) is better than single burr hole craniostomy (SBHC) in the treatment of chronic subdural hematoma (CSH), in terms of having a lower revision rate. In order to compare the revision rates after SBHC versus DBHC, we performed a meta-analysis of the available studies in the literature.Materials and Methods:Multiple electronic health databases were searched to identify all the studies published between 1966 and December 2010 that compared SBHC and DBHC. Data were processed in Review Manager 5.0.18. Effect sizes were expressed in pooled odds ratio (OR) estimates, and due to heterogeneity between studies we used random effect of the inverse variance weighted method to perform the meta-analysis.Results:Five observational retrospective cohort studies were identified: four published studies and one unpublished, describing the outcomes of 355 DBHC and 358 SBHC to evacuate 713 CSH in 631 patients. Meta-analysis showed that there was no significant difference in the revision rates between double burr hole craniostomy and single burr hole craniostomy when performed to evacuate CSH. Pooled odds ratio for all the studies was 0.62 (95% confidence interval 0.26 - 1.46).Conclusions:The results of this meta-analysis suggest that SBHC is as good as DBHC in evacuating chronic subdural hematoma and is not associated with a higher revision rate compared to DBHC.

Background: Diffusion weighted imaging (DWI) has useful diagnostic and predictive value in the assessment of glial tumors. Most studies evaluating the use of DWI in glioblastomas have done so in regions that overlap with abnormal T2/fluid attenuation inversion recovery (FLAIR) signal or contrast enhancement. Isolated DWI abnormalities, which do not overlap with contrast enhancing lesions, are less commonly described. Their relationship with the tumour, and implications for prognosis, are not well understood, though it has been speculated that these lesions may represent infiltrative tumour cells. To our knowledge, this is the first reported case where the presence of infiltrative tumour cells in an area of diffusion restriction has been confirmed via biopsy. Methods: A ring enhancing lesion and isolated DWI hyperintensity from a newly diagnosed patient were biopsied separately. Results: Pathological specimens from both targets were identified as glioblastoma (WHO Grade IV), negative for IDH-1 R132H mutation, with methylated MGMT promoter. Conclusions: In patients with glioblastoma, DWI hyperintensities distant from areas of abnormal T2/FLAIR or contrast enhancement can contain infiltrative tumour cells. The presence of isolated diffusion restriction may be a useful predictor of disease progression and prognosis but further investigation into the nature and behavior of isolated DWI lesions is required.

Background context Cervical arthroplasty is designed to maintain cervical motion of the functional spinal unit after cervical discectomy. The impact of the ProDisc-C (Synthes Spine, Paoli, PA) on in vivo kinematics and sagittal alignment requires further assessment. Purpose The purpose of this study is to test the hypothesis that the ProDisc-C increases range of motion (ROM) in flexion and extension at the surgical level, and assess its impact on cervical alignment. Study design Clinical study. Patient sample Fifteen patients with a mean age of 49 years were included in this study. Each patient had a single-level arthroplasty. Patients with multilevel arthroplasty, previous cervical spine surgery, and length of follow-up less than 6 months were excluded from this study. Outcome measure Lateral dynamic radiographs of the cervical spine were analyzed using quantitative measurement analysis (QMA) preoperatively and postoperatively. QMA software was also used to determine the ROM and sagittal translation at the surgical level. Methods Flexion/extension lateral radiographs of the cervical spine were prospectively collected and reviewed in 15 patients preoperatively and at early (1–3 months) and late (6–14 months) follow-up after placement of the ProDisc-C. Shell angle (SA) and C2–C7 Cobb angles were measured. Sagittal translation and ROM were calculated at each time point. Preoperative values were compared with early and late follow-up values using paired Student t tests and Pearson's correlation. Results The C2–C7 Cobb angle did not change significantly after surgery. Segmental ROM increased significantly from neutral to flexion (p=.02) and neutral to extension (p=.002) at late follow-up. SA correlated significantly with ROM from neutral to extension (Pearson's r =−0.55; p=.02) and translation from neutral to extension (Pearson's r =−0.58; p=.02). Conclusions The ProDisc-C increased overall segmental ROM. A lordotic SA may be associated with restricted segmental ROM and translation in extension. This study did not detect any change in overall cervical spinal alignment after insertion of the device.

Background Anterior cervical corpectomy provides the most direct and thorough surgical approach for anterior decompression when spinal cord compression is found directly behind the vertebral body. However, anterior cervical fusion has been shown to be associated with the development of new degenerative changes at levels immediately adjacent to the fused segments. The incidence of adjacent segment disease (ASD) following anterior cervical corpectomy has not been widely reported. We set out to determine the incidence of clinical ASD following anterior cervical corpectomy. Methods We retrospectively reviewed all available medical charts and radiographic studies of all cases of anterior cervical corpectomy performed at the Barrow Neurological Institute over a 4-year period with a minimum 24-month follow-up. Factors assessed included the success of arthrodesis, the presence of degenerative changes on serial follow-up radiographs, and the development of new neurological symptoms. Results Seventy-six patients met the criteria for inclusion: 54 had undergone a 1-level corpectomy, 18 underwent a 2-level corpectomy, and 4 underwent a 3- or 4-level corpectomy. Arthrodesis was performed with either allograft or autograft and anterior cervical plating. All patients achieved successful fusion. Follow-up was available for a minimum of 2 years in all cases, with a mean length of 3.6 years. Sixteen patients (21%) eventually developed radiological and clinical evidence of degenerative changes at adjacent levels. In 10 of 11 patients who developed clinical symptoms within 2 years, the changes represented progression of pre-existing, asymptomatic degenerative disease. Five patients developed degenerative changes more than 5 years after surgery; these were all associated with an unrelated new insult to the cervical spine such as trauma. Conclusions Anterior cervical corpectomy with fixation can accelerate degenerative changes identified preoperatively at adjacent, asymptomatic levels of the cervical spine. Level of Evidence Retrospective cohort study (level 2b).

OBJECTIVE: Anterior cervical discectomy and fusion (ACDF) for the management of cervical spondylosis may contribute to further degenerative changes at adjacent levels secondary to abnormal spinal motion. Insertion of a Bryan Cervical Disc (AD) (Medtronic Sofamor Danek, Memphis, TN) may prevent this accelerated degeneration. This retrospective study compares the in vivo x-ray cervical spine kinematics in patients with ACDF and AD. METHODS: Ten patients with single-level AD were matched to 10 patients with single-level ACDF based on age and sex. Lateral neutral, flexion and extension cervical x-rays were obtained preoperatively and at regular intervals up to 24 months postoperatively. Kinematic parameters, including range of motion, anteroposterior translation, and disc height, were assessed for all cervical functional spinal units using quantitative motion analysis software. Changes in these parameters were compared between matched patients from both groups using paired Student's t tests. RESULTS: The range of motion at the operated level was greater in the AD group compared with the ACDF group at early (6.9 versus 0.89 degrees, P < 0.01) and late (8.4 versus 0.53 degrees, P < 0.01) follow-up evaluations. Translation was greaterat the operated level in patients with AD at late follow-up (6.8 versus 0.8%, P< 0.03) evaluation. No significant between-group kinematic differences were seen at adjacent levels. CONCLUSION: Patients with AD and those with ACDF demonstrated similar in vivo adjacent level kinematics within the first 24 months after anterior cervical decompression.

STUDY DESIGN: Retrospective review. OBJECTIVE: To describe the incidence, clinical features, and treatment of traumatic spinal cord injury (SCI) treated at a Canadian tertiary care center. SUMMARY OF BACKGROUND DATA: Understanding the current epidemiology of acute traumatic SCI is essential for public resource allocation and primary prevention. Recent reports suggest that the mean age of patients with SCI may be increasing. METHODS: We retrospectively reviewed hospital records on all patients with traumatic SCI between January 1997 and June 2001 (n = 151). Variables assessed included age, gender, length of hospitalization, type and mechanism of injury, associated spinal fractures, neurologic deficit, and treatment. RESULTS: Annual age-adjusted incidence rates were 42.4 per million for adults aged 15-64 years, and 51.4 per million for those 65 years and older. Motor vehicle accidents accounted for 35% of SCI. Falls were responsible for 63% of SCI among patients older than 65 years and for 31% of injuries overall. Cervical SCI was most common, particularly in the elderly, and was associated with fracture in only 56% of cases. Thoracic and lumbar SCI were associated with spinal fractures in 100% and 85% of cases, respectively. In-hospital mortality was 8%. Mortality was significantly higher among the elderly. Treatment of thoracic and lumbar fractures associated with SCI was predominantly surgical, whereas cervical fractures were equally likely to be treated with external immobilization alone or with surgery. CONCLUSION: A large proportion of injuries was seen among older adults, predominantly as a result of falls. Prevention programs should expand their focus to include home safety and avoidance of falls in the elderly. Language: en

STUDY DESIGN Prospective cohort study. OBJECTIVE To assess the biomechanical profile of the cervical spine following cervical arthroplasty. SUMMARY OF BACKGROUND DATA Spinal arthroplasty offers the promise of maintaining functional spinal motion, thereby potentially avoiding adjacent segment disease. Disc replacement may become the next gold standard for the treatment of degenerative cervical spine disease, and must be studied rigorously to ensure in vivo efficacy and safety. METHODS A total of 20 patients underwent single or 2-level implantation of the Bryan artificial cervical disc (Medtronic Sofamor Danek, Memphis TN) for treatment of cervical degenerative disc disease producing radiculopathy and/or myelopathy. Lateral neutral, flexion, and extension cervical radiographs were obtained before surgery and at intervals up to 24 months after surgery. Kinematic parameters, including sagittal rotation, horizontal translation, change in disc height, and center of rotation (COR), were assessed for each spinal level using quantitative motion analysis software. RESULTS Motion was preserved in the operated spinal segments (mean range of motion 7.8 degrees) up to 24 months following surgery. The relative contribution of each spinal segment to overall spinal sagittal rotation differed depending on whether the disc was placed at C5-C6 or C6-C7. Overall cervical motion (C2-C7) was moderately but significantly increased during late follow-up. Sagittal rotation, anterior and posterior disc height, translation, and COR coordinates did not change significantly following surgery. The COR was most frequently located posterior and inferior to the center of the disc space. CONCLUSIONS The Bryan artificial cervical disc provided in vivo functional spinal motion at the operated level, reproducing the preoperative kinematics of the spondylotic disc.

Object Spinal arthroplasty may become the next gold standard for the treatment of degenerative cervical spine disease. This new modality must be studied rigorously to ensure in vivo efficacy and safety. The authors review the preliminary clinical experience and radiographic outcomes following insertion of the Bryan Cervical Disc Prosthesis (Medtronic Sofamor Danek, Memphis, TN). Methods This prospective cohort study included 26 patients undergoing single- or two-level implantation of the Bryan artificial cervical disc for treatment of cervical degenerative disc disease resulting in radiculopathy and/or myelopathy. Radiographic and clinical assessments were made preoperatively 1.5, 3 months, and at 6, 12, and up to 24 months postoperatively. The Neck Disability Index (NDI) and Short Form–36 (SF-36) questionnaires were used to assess pain and functional outcomes. Segmental sagittal rotation from C2–3 to C6–7 was measured using quantitative motion analysis software. A total of 30 Bryan discs were placed in 26 patients. A single-level procedure was performed in 22 patients and a two-level procedure in the other four. Follow-up duration ranged from 1.5 to 27 months, with a mean duration of 12.3 months. A statistically significant improvement in the mean NDI scores was seen between pre- and late postoperative follow-up evaluations. A trend toward improvement in the SF-36 physical component was also found. Motion was preserved in the treated spinal segments (mean range of motion 7.8°) for up to 24 months postsurgery. The relative contribution of each segment to overall spinal sagittal rotation differed depending on whether the disc was placed at C5–6 or C6–7. Overall cervical motion (C2–7) was moderately increased on late follow-up evaluations. Conclusions The Bryan artificial cervical disc provided in vivo functional spinal motion at the treated level. Overall cervical spinal motion was not significantly altered. Sagittal rotation did not change significantly at any level after surgery.

Object Cervical arthroplasty offers the promise of maintaining motion of the functional spinal unit (FSU) after anterior cervical discectomy. The impact of cervical arthroplasty on sagittal alignment of the FSU needs to be addressed, together with its effect on overall sagittal balance of the cervical spine. Methods The authors prospectively reviewed radiographic and clinical outcomes in 14 patients who received the Bryan Cervical Disc prosthesis (Medtronic Sofamor Danek, Memphis, TN), for whom early (< 6 months) and late (6–24 months) follow-up data were available. Static and dynamic radiographs were measured by hand and computer to determine the angles formed by the endplates of the natural disc preoperatively, those formed by the shells of the implanted prosthesis, the angle of the FSU, and the C2–7 Cobb angle. The range of motion (ROM) was also determined radiographically, whereas clinical outcomes were assessed using the Neck Disability Index (NDI), and Short Form–36 (SF-36) questionnaires. The ROM was preserved following surgery, with a mean preoperative sagittal rotation angle of 8.96°, which was not significantly different from the late postoperative value of 8.25°. When compared with the preoperative disc space angle, the shell endplate angle in the neutral position became kyphotic in the early and late postoperative periods (mean change −3.8° in the late follow-up period; p = 0.0035). The FSU angles also became significantly more kyphotic post-operatively, with a mean change of −6° (p = 0.0006). The Cobb angles varied widely preoperatively and did not change significantly after surgery. There was no statistical correlation between the NDI and SF-36 outcomes and cervical kyphosis. Conclusions Cervical arthroplasty preserves motion of the FSU. Both the endplate angle of the treated disc space and the angle of the FSU became kyphotic after insertion of the Bryan prosthesis. The overall sagittal balance of the cervical spine, however, was preserved.

Background: Focal cortical dysplasia (FCD) refers to malformation of cortical development featuring abnormalities of cortical layering, neuronal differentiation and maturation. It is a common cause of medically refractory epilepsy. The coexistence of FCD and low-grade glial neoplasms such as ganglioglioma and dysembryoplastic neuroepithelial tumour is classified by the International League Against Epilepsy as “FCD Type IIIb”. We present a case of FCD Type IIIb associated with low grade oligodendroglioma (WHO grade II) in a seizure free patient. Methods: A 20-year-old male presented with suspected arteriovenous malformation of the right pinna. Imaging revealed an incidental right frontal lobe mass. Surgical resection was performed. Pathologic analysis revealed FCD Type IIIb associated with low grade oligodendroglioma (WHO grade II). Results: The patient recovered uneventfully. Only 4 prior cases of FCD Type IIIb associated with oligodendroglioma have been reported. This is the first reported case of FCD Type IIIb discovered incidentally in a seizure free patient. Conclusions: FCD Type IIIb associated with oligodendroglioma is rare. The mechanism(s) by which glioneuronal neoplasms and perilesional cortical tissue jointly contribute to epileptogenicity have not been clearly defined. There may be a reduced risk of seizures with oligodendroglioma rather than tumors with a neuronal component.

Purpose We present a series of cases featuring re-rupture of posterior communicating artery aneurysms in the immediate post-coiling period, where clots obscured the neck of the aneurysm during the procedure. We report on the incidence of re-rupture and discuss possible mechanisms behind this phenomenon. Methods This study included 462 aneurysms over a 10-year period which were treated with endovascular coiling. 137 of these were ruptured aneurysms. Radiographic and clinical information pertaining to the patients was collected. The immediate post-coiling period was defined as ≤3 days following the procedure. Results The incidence of re-rupture in the immediate post-coiling period was 1.4% (2/137). Of these two, one received recombinant tissue plasminogen activator and both received acetylsalicylic acid. One patient presented with adjacent hematoma on re-rupture. In both cases, clot obscured the aneurysm neck during the procedure. Conclusions Re-rupture of intracranial aneurysms in the immediate post-coiling period is an exceedingly rare complication, and the events leading to it have not been discussed at length. Repeat treatment, follow-up imaging and close observation are merited in the setting of re-rupture of a posterior communicating artery aneurysm.

A case of incidentally diagnosed fenestration of the supraclinoid internal carotid artery (ICA) with an associated aneurysm is presented. We present appearances on magnetic resonance angiography, which have not been previously described. Careful interrogation of the data in volume-rendered and multiplanar reformats was required to make the diagnosis. The relationship between fenestrations and aneurysms in the anterior circulation is discussed both in general terms and with specific regard to the supraclinoid ICA. We also review the embryology of the distal ICA, which may help explain the adult anatomy of this rare lesion as a failure of caudal separation of the rostral and caudal divisions of the primitive distal ICA.

Object Spinal arthroplasty is becoming more widely performed in the treatment of degenerative cervical disc disease. Although this new technology may offer benefits over arthrodesis, it also requires that the surgeon acquire new operative techniques, and new potential complications are introduced. To determine the incidence and distribution of perioperative complications, the authors analyzed their early data obtained in a series of patients treated with the Bryan Cervical Disc prosthesis. Methods The authors prospectively recorded operative data, complications, and clinical and radiographic outcome data in all patients treated with Bryan prosthesis–based arthroplasty at two tertiary care centers since 2001. Patients underwent standard anterior cervical discectomy followed by one- to three-level arthroplasty. Ninety-six discs were implanted in 74 patients. The perioperative complication rate was 6.2% per treated level. In one patient a retropharyngeal hematoma developed, requiring evacuation. Neurological worsening occurred in three patients. Intraoperative migration of the prosthesis was observed in one two-level case, whereas delayed migration occurred in one patient with postoperative segmental kyphosis. In another patient with severe postoperative segmental kyphosis, revision was required with a customized lordotic prosthesis. Heterotopic ossification and spontaneous fusion occurred in two cases; motion was preserved in the remaining 94 prostheses. Partial dislocation of the prosthesis in extension occurred in one patient with preoperative segmental hypermobility, the first reported failure of a Bryan prosthesis. Twenty-five percent of patients reported neck and shoulder pain during the late follow-up period. There was a trend toward increased kyphosis of the C2–7 curvature postoperatively. Conclusions The Bryan prosthesis was effective in maintaining spinal motion. Major perioperative and device-related complications were infrequent.

This article focuses on the clinical results of three prostheses (the Bryan Cervical Disc, the Bristol Disc, and the ProDisc-C) for cervical total disc replacement. Background on the development, design, and biomechanical characteristics of each prosthesis is given and surgical indications and clinical results are summarized and analyzed.

Objectifs : La meilleur technique d'arthrodese et de prise en charge des patients qui subissent une dyscectomie cervicale anterieure (DCA) n'est pas bien etablie. Nous rapportons les pratiques courantes parmi les chirurgiens canadiens concernant la chirurgie pour spondylarthrose cervicale degenerative unique. Methodes : Nous avons effectue une enquete electronique aupres des neurochirurgiens et des orthopedistes pratiquant des chirurgies spinales au Canada. Le questionnaire comprenait des questions sur le traitement de la discopathie degenerative cervicale unique causant une radiculopathie et ou une myelopathie, sur la frequence de l'arthrodese apres une dyscectomie unique, la technique d'arthrodese de choix, les indications et la frequence d'utilisation d'une plaque d'osteosynthese anterieure et d'une orthese cervicale externe apres la chirurgie. Les facteurs demographiques recueillis comprenaient la formation du chirurgien, son type de pratique et la duree de celle-ci. Resultats : Soixante repondants qui ont indique que la chirurgie spinale constituait au moins 5% de leur pratique ont ete inclus dans l'etude. Parmi eux, 59% etaient des neurochirurgiens et 41% des orthopedistes. L'arthrodese etait utilisee chez 93% des patients apres une DCA; le materiau de choix etait l'os autologue utilise chez 76% des cas. Les neurochirurgiens utilisaient des plaques d'osteosynthese dans 42% des discectomies cervicales anterieures et des cas d'arthrodese alors que les orthopedistes l'utilisaient chez 70% des cas. Chez 92% des patients qui n'avait pas recu de plaque d'osteosynthese, on recommandait une orthese cervicale externe de meme que chez 61% des patients qui en avaient recu une. Les chirurgiens qui etaient en pratique depuis moins de cinq ans etaient ceux qui avaient le plus souvent recours a la chirurgie spinale, utilisaient une plaque d'osteosynthese cervicale anterieure et recommandaient l'utilisation d'une orthese cervicale apres la chirurgie. Conclusion : Bien qu'il existe des variations dans les techniques utilisees par les chirurgiens canadiens, presque tous utilisent l'arthrodese et plusieurs utilisent l'instrumentation pour la DCA unique. La formation du chirurgien, son type de pratique et la duree de celle-ci influencent ses choix.

Patients with multiple sclerosis (MS) have a relatively high incidence of tic douloureux (TD) and often do not tolerate medical therapy well. The minimally invasive nature of percutaneous retrogasserian glycerol rhizotomy (PRGR) renders it ideal for first-line surgical treatment of TD. We sought to ascertain the benefits of PRGR in patients with MS and to determine whether hypalgesia after PRGR correlates with efficacy.We assessed 97 glycerol procedures performed in 53 patients followed prospectively for treatment of TD associated with MS. Factors assessed included degree of pain relief, postoperative hypalgesia, procedural morbidity, medication use, time to pain recurrence, and number and type of subsequent procedures.Complete pain relief was obtained in 78% of patients after the initial glycerol injection, and partial relief was obtained in 13% of patients. Long-term follow-up (mean, 81 mo) demonstrated a recurrence rate of 59%, with a mean time to recurrence of 17 months. Actuarial recurrence rates were 50% at 12 months and 60% at 24 months. Twenty-four patients underwent a second or subsequent PRGR for recurrent pain and achieved similar rates of pain relief and time to recurrence. Facial sensory loss was associated with a higher likelihood of pain relief (P0.05), with longer time to pain recurrence (P0.05), and with decreased use of medication after surgery (P0.01.)PRGR is an effective, low-morbidity surgical procedure in the management of TD complicating MS. The presence of facial sensory loss after PRGR is associated with prolonged efficacy.

Objective and importance:Fusion following anterior cervical discectomy has been implicated in the acceleration of degenerative changes in the adjacent spinal segments. Discectomy followed by implantation of an artificial cervical disc maintains the functionality of the spinal unit, while still providing excellent symptomatic relief. We describe our preliminary experience with implantation of the Bryan Cervical Disc System in two cases of single-level cervical disc herniation.Clinical presentation:Two male patients presented with a left C6 radiculopathy, without evidence of myelopathy. Magnetic resonance imaging revealed a disc herniation at C5-6 in both cases. Pre-operative flexion and extension radiographs demonstrated preserved motion at the involved levels.Intervention/technique:Following a standard anterior cervical decompression, precision drilling of the vertebral endplates was carried out using a drill attached to a bed-mounted, gravitationally-referenced retraction frame. An artificial cervical disc, composed of a polyurethane nucleus with titanium endplates, was fitted between the contoured endplates without fixation to the vertebral bodies. No complications were experienced during the insertion of the prosthesis, or in the postoperative course. Both patients experienced immediate postoperative resolution of their radicular pain and were discharged from hospital the following day. At nine months following surgery, both patients continue to have complete relief of radicular symptoms. Postoperative radiographs at six months following surgery confirm accurate placement of the prosthesis and preserved mobility of the functional spinal unit.Conclusion:Insertion of the Bryan artificial cervical disc prosthesis following anterior cervical discectomy is a relatively straightforward procedure, which appears to be safe and provides good clinical results, without requiring additional surgical time. Long-term follow-up is required to assess its safety, efficacy, and ability to prevent adjacent segment degeneration.

Purpose Flow diverters are the latest technology in the treatment of difficult/so far untreatable aneurysms. As with all new technologies, there is lots of “hype” factor for flow diverters as well. For a beginner in the field of interventional neuroradiology, it is usually not advisable to venture into the difficult cases in the beginning of the carrier. However for a new technology, every body is a beginner. The purpose of this presentation is to discuss important points that a beginner in the field should know about how to proceed for the SILK flow diverter technology. Materials and Method We treated a total of seven patients with aneurysms which were branded as non-treatables or extremely difficult to treat with the conventional treatment techniques. Before actually starting the treatment, the most important point is to educate and make a consensus among the vascular neurosurgeons and interventional neuroradiology. Organizing an in-service with the company is helpful in this. Getting approval from healthcare regulatory agency (Health Canada) and proctorship are the next steps. The most important part for a new technology is proper case selection. Management of the patient per se starts with talking with the patient about the technology, the rationale for its use and lack of its long term outcome. This is followed by the periprocedural management most important being the anti-platelet medications and steroids. Eventually the follow-up is the most important step to maintain the credibility of both the new treatment and the new operator. Result The aneurysms in our patient group were located at cavernous/ophthalimic segment of internal carotid artery (n=5), basilar trunk (n=1) and A2 segment of anterior cerebral artery (n=1). Five of these patients were done under the guidance of the proctor and last two patients were done independently. We had 100% technical success. No technical complications. One patient had mild hemiparesis which improved over a period of next 5 days. Another patient had spontaneous occlusion of her parent artery 2 months after the treatment as she stopped taking antiplatelet drugs. Other patient had no complications. All patients were followed up using CEMRA to begin with and the confirmation of complete occlusion was validated using DSA. We had an average follow-up of 3 months (0 to 7 months). One patient had confirmed exclusion of his aneurysm on MRI 3 months after the initial treatment and other patient had occlusion of her parent artery 2 months after the initial treatment. Conclusion Education, proper training, proper case selection, patience and team support are the most important factors to consider when venturing into a relatively new territory in the first year of your carrier.

OBJECTIVE Hydrogel-coated coils (MicroVention, Inc., Aliso Viejo, CA) for endovascular aneurysm treatment offer the theoretical advantages of increased volumetric occlusion, thrombus stabilization, and improved neointimal healing. Reports of local inflammation and hydrocephalus after coiling of unruptured aneurysms have raised questions about the safety profile or appropriate usage of these new devices. CLINICAL PRESENTATION Two patients with large ophthalmic aneurysms underwent elective endovascular coiling with HydroCoils. Three to 4 weeks later, they developed profound, progressive bilateral visual loss. Magnetic resonance imaging scans demonstrated extensive enhancement of the coil ball, surrounding brain parenchyma, and optic chiasm, with perianeurysmal edema. INTERVENTION Dexamethasone produced impressive but temporary improvement in vision in one patient; the other experienced only minor improvement. One patient also developed hydrocephalus; ventriculoperitoneal shunting reduced ventricular size but had no effect on vision. Follow-up imaging demonstrated persistent enhancement of the coil ball, as well as recurrence and extension of the abnormal signal in the parenchyma and along the optic tract. CONCLUSION Both patients have been left with no functional vision in the eye ipsilateral to the aneurysm and have experienced marked visual field loss and reduced acuity in the contralateral eye. Ongoing international studies will provide more information on the rate of inflammatory complications. The biological mechanisms underlying the phenomenon also require investigation. Meanwhile, we caution against using HydroCoils in situations in which worsened mass effect or local inflammation would have highly deleterious consequences, such as in large aneurysms adjacent to the visual pathways or the brainstem.

OBJECTIVE: Patients with multiple sclerosis (MS) have a relatively high incidence of tic douloureux (TD) and often do not tolerate medical therapy well. The minimally invasive nature of percutaneous retrogasserian glycerol rhizotomy (PRGR) renders it ideal for first-line surgical treatment of TD. We sought to ascertain the benefits of PRGR in patients with MS and to determine whether hypalgesia after PRGR correlates with efficacy. METHODS: We assessed 97 glycerol procedures performed in 53 patients followed prospectively for treatment of TD associated with MS. Factors assessed included degree of pain relief, postoperative hypalgesia, procedural morbidity, medication use, time to pain recurrence, and number and type of subsequent procedures. RESULTS: Complete pain relief was obtained in 78% of patients after the initial glycerol injection, and partial relief was obtained in 13% of patients. Long-term follow-up (mean, 81 mo) demonstrated a recurrence rate of 59%, with a mean time to recurrence of 17 months. Actuarial recurrence rates were 50% at 12 months and 60% at 24 months. Twenty-four patients underwent a second or subsequent PRGR for recurrent pain and achieved similar rates of pain relief and time to recurrence. Facial sensory loss was associated with a higher likelihood of pain relief (P < 0.05), with longer time to pain recurrence (P < 0.05), and with decreased use of medication after surgery (P < 0.01.) CONCLUSION: PRGR is an effective, low-morbidity surgical procedure in the management of TD complicating MS. The presence of facial sensory loss after PRGR is associated with prolonged efficacy.