Do expandable cage size and number of cages matter in transforaminal lumbar interbody fusion at L5-S1? A comparative biomechanical analysis using finite element modeling

OBJECTIVE

Expandable transforaminal lumbar interbody fusion (TLIF) cages were designed to address the limitations of static cages. Bilateral cage insertion can potentially enhance stability, fusion rates, and segmental lordosis. However, the benefits of unilateral versus bilateral expandable cages with varying sizes in TLIF remain unclear. This study used a validated finite element spine model to compare the biomechanical properties of L5-S1 TLIF by using differently sized expandable cages inserted unilaterally or bilaterally.

METHODS

A finite element model of X-PAC expandable lumbar cages was created and used at the L5-S1 level. This model had cage dimensions of 9 mm in height, 15° in lordosis, and varying widths and lengths. Various placements (unilateral vs bilateral) and sizes were examined under pure moment loading to evaluate range of motion, adjacent-segment motion, and endplate stress.

RESULTS

Stability at the L5-S1 level decreased when smaller cages were used in both the unilateral and bilateral cage models. In the unilateral model, cage 1 (the smallest cage) resulted in 47.9% more motion at the L5-S1 level compared to cage 5 (the largest cage) in flexion, as well as 64.8% more motion in extension. Similarly, in the bilateral TLIF model, bilateral cage 1 led to 49.4% more motion at the L5-S1 level in flexion and 73.4% more motion in extension compared to bilateral cage 5. Unilateral insertion of cage 5 provided superior stability in flexion and surpassed cages 1-3 in extension when compared to cages inserted either unilaterally or bilaterally. Reduced motion at L5-S1 correlated with increased adjacent-segment motion at L4-5. Bilateral TLIF resulted in greater adjacent-segment motion compared to unilateral TLIF with the same-size cages. Inferior endplates experienced higher stress during flexion and extension than superior endplates, with this difference being more pronounced in the bilateral model. In bilateral cage placement, stress differences ranged from 46.3% to 60.0%, while they ranged from 1.1% to 9.6% in unilateral cages. Qualitative analysis revealed increased focal stress in unilateral cages versus bilateral cages.

CONCLUSIONS

The authors' study shows that using a large unilateral TLIF cage may offer better stability than the bilateral insertion of smaller cages. While large bilateral cages increase adjacent-segment motion, they also provide a uniform stress distribution on the endplates. These findings deepen our understanding of the biomechanics of the available expandable TLIF cages.

Large cervical spinal schwannoma requiring anterior and posterior decompression and fusion with careful dissection of the vertebral artery

We report a challenging case of a high cervical schwannoma with involvement of the right vertebral artery that could not be sacrificed. We discuss the clinical presentation, surgical approach/techniques, and brief literature review of cervical schwannomas. Our case includes a 58-year-old male referred to neurosurgery due to worsening pain and ataxia, who was found to have a large right sided cervical mass. Early challenges such as C4 vertebral body erosion and vertebral artery encasement were demonstrated on imaging. While vertebral artery endovascular sacrifice was considered[1], a balloon occlusion test elicited significant neurologic deficits for our patient, making potential sacrifice high risk. He underwent resection of the tumor with careful dissection of the tumor off the vertebral artery, thus allowing for its preservation, followed by spinal fixation. Schwannomas are a benign tumor of Schwann Cells and can be insidious in onset with the capability to cause serious neurologic deficits if unchecked[2]. The surgical treatment of such masses is classically done with resection and fixation with instrumentation if necessary[3]. Safe access to the tumor without avulsing nerve roots requires extensive bony resection, often times necessitating facetectomies and pediculectomies[4]. A series evaluating similar tumors determined that the extent of involvement of the vertebral artery predicts the extent of resection[5]. Our case demonstrates the key steps required for dissecting the vertebral artery in order to safely achieve gross total resection. The patient provided consent for treatment and to allow his interesting case to be utilized for scientific review and publication.

Management of a recurrent spinal arachnoid cyst presenting as arachnoiditis in the setting of spontaneous spinal subarachnoid hemorrhage: illustrative case

BACKGROUND

Spontaneous spinal subarachnoid hemorrhage is a rare pathological entity with a variety of presentations depending on the underlying etiology, which often remains cryptogenic. The literature is sparse regarding the most efficacious treatment or management option, and there is no consensus on follow-up time or modalities. Additionally, there are very few reports that include operative videos, which is provided herein.

OBSERVATIONS

The authors present a case of spontaneous spinal subarachnoid hemorrhage without an underlying etiology in a patient with progressive myelopathy, back pain, and lower-extremity paresthesias. She presented to our institution, and because of progressive worsening of her symptoms and the development of compressive arachnoid cysts, she underwent thoracic laminectomies for evacuation of subdural fluid, fenestration of the arachnoid cysts, and lysis of significant arachnoid adhesions. Her clinical course was further complicated by the recurrence of worsening myelopathy and the development of a large compressive arachnoid cyst with further arachnoiditis. The patient underwent repeat surgical intervention for cyst decompression with an improvement in symptoms.

LESSONS

This case highlights the importance of long-term follow-up for these complicated cases with an emphasis on repeat magnetic resonance imaging. Unfortunately, surgical intervention is associated with short-term relief of the symptoms and no significant nonoperative management is available for these patients.

Effect of Feedback Modality on Simulated Surgical Skills Learning Using Automated Educational Systems- A Four-Arm Randomized Control Trial

OBJECTIVE

To explore optimal feedback methodologies to enhance trainee skill acquisition in simulated surgical bimanual skills learning during brain tumor resections.

HYPOTHESES

(1) Providing feedback results in better learning outcomes in teaching surgical technical skill when compared to practice alone with no tailored performance feedback. (2) Providing more visual and visuospatial feedback results in better learning outcomes when compared to providing numerical feedback.

DESIGN

A prospective 4-parallel-arm randomized controlled trial.

SETTING

Neurosurgical Simulation and Artificial Intelligence Learning Centre, McGill University, Canada.

PARTICIPANTS

Medical students (n = 120) from 4 Quebec medical schools.

RESULTS

Participants completed a virtually simulated tumor resection task 5 times while receiving 1 of 4 feedback based on their group allocation: (1) practice-alone without feedback, (2) numerical feedback, (3) visual feedback, and (4) visuospatial feedback. Outcome measures were participants' scores on 14-performance metrics and the number of expert benchmarks achieved during each task. There were no significant differences in the first task which determined baseline performance. A statistically significant interaction between feedback allocation and task repetition was found on the number of benchmarks achieved, F (10.558, 408.257)=3.220, p < 0.001. Participants in all feedback groups significantly improved their performance compared to baseline. The visual feedback group achieved significantly higher number of benchmarks than the practice-alone group by the third repetition of the task, p = 0.005, 95%CI [0.42 3.25]. Visual feedback and visuospatial feedback improved performance significantly by the second repetition of the task, p = 0.016, 95%CI [0.19 2.71] and p = 0.003, 95%CI [0.4 2.57], respectively.

CONCLUSION

Simulations with autonomous visual computer assistance may be effective pedagogical tools in teaching bimanual operative skills via visual and visuospatial feedback information delivery.

Performance in a Simulated Virtual Reality Anterior Cervical Discectomy and Fusion Task: Disc Residual, Rate of Removal, and Efficiency Analyses

BACKGROUND AND OBJECTIVES

Anterior cervical discectomy and fusion (ACDF) is among the most common spine procedures. The Sim-Ortho virtual reality simulator platform contains a validated ACDF simulated task for performance assessment. This study aims to develop a methodology to extract three-dimensional data and reconstruct and quantitate specific simulated disc tissues to generate novel metrics to analyze performance metrics of skilled and less skilled participants.

METHODS

We used open-source platforms to develop a methodology to extract three-dimensional information from ACDF simulation data. Metrics generated included, efficiency index, disc volumes removed from defined regions, and rate of tissue removal from superficial, central, and deep disc regions. A pilot study was performed to assess the utility of this methodology to assess expertise during the ACDF simulated procedure.

RESULTS

The system outlined, extracts data allowing the development of a methodology which accurately reconstructs and quantitates 3-dimensional disc volumes. In the pilot study, data sets from 27 participants, divided into postresident, resident, and medical student groups, allowed assessment of multiple novel metrics, including efficiency index (surgical time spent in actively removing disc), where the postresident group spent 61.8% of their time compared with 53% and 30.2% for the resident and medical student groups, respectively ( P = .01). During the annulotomy component, the postresident group removed 47.4% more disc than the resident groups and 102% more than the medical student groups ( P = .03).

CONCLUSION

The methodology developed in this study generates novel surgical procedural metrics from 3-dimensional data generated by virtual reality simulators and can be used to assess surgical performance.

AI in Surgical Curriculum Design and Unintended Outcomes for Technical Competencies in Simulation Training

Importance

To better elucidate the role of artificial intelligence (AI) in surgical skills training requires investigations in the potential existence of a hidden curriculum.

Objective

To assess the pedagogical value of AI-selected technical competencies and their extended effects in surgical simulation training.

Design, Setting, and Participants

This cohort study was a follow-up of a randomized clinical trial conducted at the Neurosurgical Simulation and Artificial Intelligence Learning Centre at the Montreal Neurological Institute, McGill University, Montreal, Canada. Surgical performance metrics of medical students exposed to an AI-enhanced training curriculum were compared with a control group of participants who received no feedback and with expert benchmarks. Cross-sectional data were collected from January to April 2021 from medical students and from March 2015 to May 2016 from experts. This follow-up secondary analysis was conducted from June to September 2022. Participants included medical students (undergraduate year 0-2) in the intervention cohorts and neurosurgeons to establish expertise benchmarks.

Exposure

Performance assessment and personalized feedback by an intelligent tutor on 4 AI-selected learning objectives during simulation training.

Main Outcomes and Measures

Outcomes of interest were unintended performance outcomes, measured by significant within-participant difference from baseline in 270 performance metrics in the intervention cohort that was not observed in the control cohort.

Results

A total of 46 medical students (median [range] age, 22 [18-27] years; 27 [59%] women) and 14 surgeons (median [range] age, 45 [35-59] years; 14 [100%] men) were included in this study, and no participant was lost to follow-up. Feedback on 4 AI-selected technical competencies was associated with additional performance change in 32 metrics over the entire procedure and 20 metrics during tumor removal that was not observed in the control group. Participants exposed to the AI-enhanced curriculum demonstrated significant improvement in safety metrics, such as reducing the rate of healthy tissue removal (mean difference, -7.05 × 10-5 [95% CI, -1.09 × 10-4 to -3.14 × 10-5] mm3 per 20 ms; P < .001) and maintaining a focused bimanual control of the operative field (mean difference in maximum instrument divergence, -4.99 [95% CI, -8.48 to -1.49] mm, P = .006) compared with the control group. However, negative unintended effects were also observed. These included a significantly lower velocity and acceleration in the dominant hand (velocity: mean difference, -0.13 [95% CI, -0.17 to -0.09] mm per 20 ms; P < .001; acceleration: mean difference, -2.25 × 10-2 [95% CI, -3.20 × 10-2 to -1.31 × 10-2] mm per 20 ms2; P < .001) and a significant reduction in the rate of tumor removal (mean difference, -4.85 × 10-5 [95% CI, -7.22 × 10-5 to -2.48 × 10-5] mm3 per 20 ms; P < .001) compared with control. These unintended outcomes diverged students' movement and efficiency performance metrics away from the expertise benchmarks.

Conclusions and Relevance

In this cohort study of medical students, an AI-enhanced curriculum for bimanual surgical skills resulted in unintended changes that improved performance in safety but negatively affected some efficiency metrics. Incorporating AI in course design requires ongoing assessment to maintain transparency and foster evidence-based learning objectives.

COMPARING THE EFFICIENCY OF A REAL-TIME ARTIFICIAL INTELLIGENCE INSTRUCTOR TO HUMAN EXPERT INSTRUCTORS IN SIMULATED SURGICAL TECHNICAL SKILLS TRAINING– A RANDOMIZED CONTROLLED TRIAL

BTFC travel award recipient

Artificial intelligence systems provide risk-free training on realistically simulated patient cases and objective assessment of surgical technical skills. This randomized controlled study compared a real-time intelligent tutoring system in technical skills learning with human expert instructor-mediated training.

METHODS: Ninety-eight medical students performed six simulated brain tumor resections. Participants were randomly allocated into (1)no-real-time feedback, (2)real-time intelligent instruction, and (3)in- person human instruction. All students performed the first repetition without receiving feedback (baseline). Group-1 received visual feedback only after each procedure based on expert benchmarks. Group-2 was instructed by the intelligent system in real-time. After each task, the students were shown their error-video clips generated by this system alongside expert-level demonstrations on how to improve. Group-3 was instructed by human instructors during the tasks. After each task, instructors summarized the areas of improvement and demonstrated correction techniques. Participant performance was scored by the intelligent system and also by blinded experts using OSATS scores. The performance score was compared within groups and between groups to compare learning. RESULTS: Compared to baseline performance, Group-2 and Group-3 significantly improved in the performance score by the third and second repetition, respectively (p<0.01, p=0.01). The between-groups comparison demonstrated that Group-2 scored significantly higher than Group-3 in the fifth repetition (p<0.01). Group-2 achieved significantly higher OSATS scores than Group-1 in the sixth task. CONCLUSIONS: Artificial intelligence may facilitate trainee learning by providing equally or more efficient learning when compared to human instruction. These systems may aid in developing competency-based standardized curricula in surgical training.

The Central Sulcus of the Insula: A Highly Reliable Radiographic Landmark for Identification of the Rolandic Sulcus

BACKGROUND

Anatomic studies have suggested that the central insular sulcus (CIS) runs in line with the Rolandic sulcus (RS). The radiographic relationship between the RS and CIS has not been systematically studied. This study aims to evaluate the applicability of using the CIS as a radiologic landmark to identify the RS.

METHODS

We retrospectively reviewed 100 consecutive normal magnetic resonance imaging (MRI) scans (200 hemispheres) performed at a single institution. MRI scans with any intracranial pathology or finding were excluded. Sagittal and axial fluid-attenuated inversion recovery sequences were used in this study. Two evaluators independently evaluated the relationship of the CIS and RS in all MRI scans. A predefined 3-step method was then used to identify the CIS, RS, and hand motor area in sagittal and axial images.

RESULTS

The CIS was found to be correlated with the RS in 191 hemispheres (95.5%). In the remaining 9 hemispheres, the postcentral sulcus represented the most correlated sulcus with the CIS (7 hemispheres). The interrater agreement was 0.673 (P < 0.05), indicating a substantial agreement. The hand motor area was identified in the same section as the CIS in 175 hemispheres (87.5%).

CONCLUSIONS

The CIS is a highly reliable radiographic landmark for the identification of the RS. The hand motor area can also be identified reliably using this method.

Nondominant Hand Skills Spatial and Psychomotor Analysis During a Complex Virtual Reality Neurosurgical Task-A Case Series Study

BACKGROUND

Virtual reality surgical simulators provide detailed psychomotor performance data, allowing qualitative and quantitative assessment of hand function. The nondominant hand plays an essential role in neurosurgery in exposing the operative area, assisting the dominant hand to optimize task execution, and hemostasis. Outlining expert-level nondominant hand skills may be critical to understand surgical expertise and aid learner training.

OBJECTIVE

To (1) provide validity for the simulated bimanual subpial tumor resection task and (2) to use this simulation in qualitative and quantitative evaluation of nondominant hand skills for bipolar forceps utilization.

METHODS

In this case series study, 45 right-handed participants performed a simulated subpial tumor resection using simulated bipolar forceps in the nondominant hand for assisting the surgery and hemostasis. A 10-item questionnaire was used to assess task validity. The nondominant hand skills across 4 expertise levels (neurosurgeons, senior trainees, junior trainees, and medical students) were analyzed by 2 visual models and performance metrics.

RESULTS

Neurosurgeon median (range) overall satisfaction with the simulated scenario was 4.0/5.0 (2.0-5.0). The visual models demonstrated a decrease in high force application areas on pial surface with increased expertise level. Bipolar-pia mater interactions were more focused around the tumoral region for neurosurgeons and senior trainees. These groups spent more time using the bipolar while interacting with pia. All groups spent significantly higher time in the left upper pial quadrant than other quadrants.

CONCLUSION

This work introduces new approaches for the evaluation of nondominant hand skills which may help surgical trainees by providing both qualitative and quantitative feedback.

Effect of Artificial Intelligence Tutoring vs Expert Instruction on Learning Simulated Surgical Skills Among Medical Students: A Randomized Clinical Trial

IMPORTANCE

To better understand the emerging role of artificial intelligence (AI) in surgical training, efficacy of AI tutoring systems, such as the Virtual Operative Assistant (VOA), must be tested and compared with conventional approaches.

OBJECTIVE

To determine how VOA and remote expert instruction compare in learners' skill acquisition, affective, and cognitive outcomes during surgical simulation training.

DESIGN, SETTING, AND PARTICIPANTS

This instructor-blinded randomized clinical trial included medical students (undergraduate years 0-2) from 4 institutions in Canada during a single simulation training at McGill Neurosurgical Simulation and Artificial Intelligence Learning Centre, Montreal, Canada. Cross-sectional data were collected from January to April 2021. Analysis was conducted based on intention-to-treat. Data were analyzed from April to June 2021.

INTERVENTIONS

The interventions included 5 feedback sessions, 5 minutes each, during a single 75-minute training, including 5 practice sessions followed by 1 realistic virtual reality brain tumor resection. The 3 intervention arms included 2 treatment groups, AI audiovisual metric-based feedback (VOA group) and synchronous verbal scripted debriefing and instruction from a remote expert (instructor group), and a control group that received no feedback.

MAIN OUTCOMES AND MEASURES

The coprimary outcomes were change in procedural performance, quantified as Expertise Score by a validated assessment algorithm (Intelligent Continuous Expertise Monitoring System [ICEMS]; range, -1.00 to 1.00) for each practice resection, and learning and retention, measured from performance in realistic resections by ICEMS and blinded Objective Structured Assessment of Technical Skills (OSATS; range 1-7). Secondary outcomes included strength of emotions before, during, and after the intervention and cognitive load after intervention, measured in self-reports.

RESULTS

A total of 70 medical students (41 [59%] women and 29 [41%] men; mean [SD] age, 21.8 [2.3] years) from 4 institutions were randomized, including 23 students in the VOA group, 24 students in the instructor group, and 23 students in the control group. All participants were included in the final analysis. ICEMS assessed 350 practice resections, and ICEMS and OSATS evaluated 70 realistic resections. VOA significantly improved practice Expertise Scores by 0.66 (95% CI, 0.55 to 0.77) points compared with the instructor group and by 0.65 (95% CI, 0.54 to 0.77) points compared with the control group (P < .001). Realistic Expertise Scores were significantly higher for the VOA group compared with instructor (mean difference, 0.53 [95% CI, 0.40 to 0.67] points; P < .001) and control (mean difference. 0.49 [95% CI, 0.34 to 0.61] points; P < .001) groups. Mean global OSATS ratings were not statistically significant among the VOA (4.63 [95% CI, 4.06 to 5.20] points), instructor (4.40 [95% CI, 3.88-4.91] points), and control (3.86 [95% CI, 3.44 to 4.27] points) groups. However, on the OSATS subscores, VOA significantly enhanced the mean OSATS overall subscore compared with the control group (mean difference, 1.04 [95% CI, 0.13 to 1.96] points; P = .02), whereas expert instruction significantly improved OSATS subscores for instrument handling vs control (mean difference, 1.18 [95% CI, 0.22 to 2.14]; P = .01). No significant differences in cognitive load, positive activating, and negative emotions were found.

CONCLUSIONS AND RELEVANCE

In this randomized clinical trial, VOA feedback demonstrated superior performance outcome and skill transfer, with equivalent OSATS ratings and cognitive and emotional responses compared with remote expert instruction, indicating advantages for its use in simulation training.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04700384.

Ventriculoatrial Shunts: Review of Technical Aspects and Complications

Diversion of cerebrospinal fluid is required in many neurosurgical conditions. When a standard ventriculoperitoneal shunt and endoscopic third ventriculostomy are not appropriate options, placement of a ventriculoatrial shunt is a safe, relatively familiar second-line shunting procedure. Herein we reviewed the technical aspects of ventriculoatrial shunt placement using an illustrative case. We focused on the different modalities for inserting and confirming the location of the distal catheter tip. We discussed how to overcome typical difficulties and significant concerns, such as cardiac arrhythmias and venous thrombosis. In addition, we reviewed the current literature for the different complications associated with ventriculoatrial shunt placement.

Accuracy of Pedicle Screw Placement Using Intraoperative CT-Guided Navigation and Conventional Fluoroscopy for Lumbar Spondylosis

Background

Transpedicular screws are a common adjunct for lumbar spine fusion. Accurate screw placement to prevent neurological injury has been the subject of many studies. The adoption of spine neuronavigation has shown a significant decrease in screw malposition morbidity. We aim to evaluate the accuracy of pedicle screw insertion using intraoperative CT-guided navigation in lumbar spondylosis.

Methods

We reviewed a prospective registry-based cohort study. This included patients who underwent transpedicular screws insertion for lumbar spondylosis under intraoperative CT-guided navigation (iCT-Nav) and compared it to another group operated using conventional fluoroscopy (FS) over one year. In addition, the correlation between clinical outcome using the visual analog scale (VAS) and short 12 physical component scores (SF-12 PCS) and hospital stay was reported.

Results

Fifteen patients were included in the iCT-Nav group compared to 42 patients in the FS group. The median age of the iCT-Nav group was 59.3 years old (27-76 years) versus 45 years old (20-60 years) in the FS group. The number of screws was 98 in the iCT-Nav group and 252 screws in the FS group. Based on more than 2-mm breach increments measured on CT images, lumbar pedicular screw placement accuracy was 100% in the iCT-Nav group and 86.9% in the FS group. None of the patients in the iCT-Nav group had to undergo any postoperative revisions. On the other hand, two patients of the FS group developed new postoperative symptoms related to displaced screws and required readmission and revision surgery.

Conclusion

In a commonly performed pedicular fixation in lumbar spondylosis, iCT-Nav has been shown to improve the accuracy of pedicle screw placement, hospital stay, and functional outcomes compared to FS. 

Best Practices Using Ex Vivo Animal Brain Models in Neurosurgical Education to Assess Surgical Expertise

BACKGROUND

Ex vivo animal brain simulation models are being increasingly used for neurosurgical training because these models can replicate human brain conditions. The goal of the present report is to provide the neurosurgical community interested in using ex vivo animal brain simulation models with guidelines for comprehensively and rigorously conducting, documenting, and assessing this type of research.

METHODS

In consultation with an interdisciplinary group of physicians and researchers involved in ex vivo models and a review of the literature on the best practices guidelines for simulation research, we developed the "ex vivo brain model to assess surgical expertise" (EVBMASE) checklist. The EVBMASE checklist provides a comprehensive quantitative framework for analyzing and reporting studies involving these models. We applied The EVBMASE checklist to the studies reported of ex vivo animal brain models to document how current ex vivo brain simulation models are used to train surgical expertise.

RESULTS

The EVBMASE checklist includes defined subsections and a total score of 20, which can help investigators improve studies and provide readers with techniques to better assess the quality and any deficiencies of the research. We classified 18 published ex vivo brain models into modified (group 1) and nonmodified (group 2) models. The mean total EVBMASE score was 11 (55%) for group 1 and 4.8 (24.2%) for group 2, a statistically significant difference (P = 0.006) mainly attributed to differences in the simulation study design section (P = 0.003).

CONCLUSIONS

The present findings should help contribute to more rigorous application, documentation, and assessment of ex vivo brain simulation research.

Dural Venous Sinus Thrombosis in Patients Presenting with Blunt Traumatic Brain Injuries and Skull Fractures: A Systematic Review and Meta-Analysis

BACKGROUND

Dural venous sinus thrombosis (DVST) is an increasingly recognized complication of blunt traumatic brain injury (TBI) and skull fractures. However, data concerning epidemiology and clinical significance of DVST are unclear. Determining the disease burden in patients with TBI is an important first step to guide future studies assessing the natural course of traumatic DVST or the effects of its treatment. Therefore, we performed to our knowledge the first systematic review and meta-analysis evaluating the prevalence of DVST in patients with TBI and skull fractures.

METHODS

MEDLINE and Embase databases were systematically searched for relevant studies published up to March 2018. All studies that assessed the prevalence of DVST among patients with TBI who underwent a vascular imaging study were included. The primary outcome was the presence or absence of DVST on imaging. A random-effects meta-analysis was used to pool studies.

RESULTS

Our systematic review yielded 638 articles, and 13 articles met inclusion criteria. In patients with skull fractures adjacent to a venous sinus, the prevalence was 26.2% (95% confidence interval = 19.4%-34.4%). This elevated risk was similar between adult (pooled estimate 23.8%; 95% CI = 16.2%-33.5%) and pediatric (pooled estimate 31.3%; 95% CI = 19.1%-46.9%) populations.

CONCLUSIONS

We found an unexpectedly high and consistent frequency of DVST among patients with skull fractures regardless of age group or severity of brain injury. These findings are important and highlight the need for further understanding the natural history of DVST and providing better guidelines on its management.

Intracranial Dystrophic Calcification of Ventriculoperitoneal Shunt: A Case Report

Ventriculoperitoneal (VP) shunting is one of the most common simple neurosurgical procedures. VP shunt catheters are made of silicone-coated Silastic tubes, which are made to be inert and hardly induce any reaction in normal tissue. We report a rare case of an extensive intracranial calcification of a VP shunt. This is a very rare case of a documented extensive calcification around the ventricular catheter of a VP shunt. We review the previously reported cases in the literature and present our management of the case. We discuss the possible mechanisms for such a dystrophic calcification around a VP shunt.

Invasive Orbital Apex Aspergillosis with Mycotic Aneurysm Formation and Subarachnoid Hemorrhage in Immunocompetent Patients

BACKGROUND

Invasive orbital apex aspergillosis (IOAA) is an aggressive form of aspergillus infection that usually affects immunocompromised patients. It can cause orbital apex syndrome and, if not treated promptly, may progress rapidly causing fatal complications. Subarachnoid hemorrhage (SAH) secondary to ruptured mycotic aneurysms is a very rare complication of invasive aspergillosis. We aim to describe our management and the outcome of six immunocompetent patients with IOAA with subsequent SAH secondary to ruptured mycotic aneurysms.

PATIENTS AND METHODS

A retrospective review was undertaken of charts of patients treated for orbital involvement with aspergillosis between January 2003 and December 2015 at King Abdulaziz University Hospital, Jeddah, Saudi Arabia. We identified all immunocompetent patients with IOAA who developed vascular complications.

RESULTS

Six immunocompetent patients with IOAA complicated by SAH secondary to ruptured mycotic aneurysms were identified in the study period. Four patients were female, and patients' age ranged between 14 and 53 years (mean, 33.7 ± 13.4 years). All patients presented with progressive retro-orbital headache, visual impairment, and ophthalmoplegia; four had proptosis. Two patients had vasospasm and brain infarction. Antifungal therapy was used in all patients, and 4 underwent emergency craniotomy and clipping of an aneurysm. Five patients died as a consequence of SAH and infarction.

CONCLUSIONS

IOAA is a serious disease that commonly causes catastrophic and fatal vascular complications.

Human Immunodeficiency Virus-Associated Cerebral Aneurysmal Vasculopathy: A Systematic Review

BACKGROUND

Human immunodeficiency virus (HIV)-associated cerebral aneurysmal vasculopathy is a rare complication of HIV affecting pediatric and adult patients and has been the subject of many case reports and case series.

METHODS

We performed a systematic literature search of PubMed, EMBASE, Scopus, Web of Science, Science Direct, and Google Scholar up to April 10, 2015. Our inclusion criteria encompassed all reported original case series and reports of HIV-associated cerebral aneurysms diagnosed radiologically. We analyzed the clinical characteristics and management of the reported cases.

RESULTS

We identified 61 patients reported in the literature (45 pediatric and 16 adult patients). The median age was 9.8 years for pediatric patients and 36.5 years for adult patients. Weakness was the most common presenting symptom in adult and pediatric patients. The most common affected artery was the middle cerebral artery. Approximately 87.2% of pediatric patients and 42.9% of adult patients were on antiretroviral therapy (ART) at presentation. The mortality rate was 60% and 35.7% among pediatric and adult patients, respectively. The optimal management is not well established. Variable response to ART was reported with possible survival benefits when ART was initiated early.

CONCLUSIONS

HIV-associated cerebral aneurysmal arteriopathy is associated with high mortality. The optimal management is not well established, but early initiation of ART may improve the survival rate.