Treatment of pediatric intracranial aneurysms: institutional case series and systematic literature review

INTRODUCTION

Pediatric intracranial aneurysms (IAs) are rare and have distinct clinical profiles compared to adult IAs. They differ in location, size, morphology, presentation, and treatment strategies. We present our experience with pediatric IAs over an 18-year period using surgical and endovascular treatments and review the literature to identify commonalities in epidemiology, treatment, and outcomes.

METHODS

We identified all patients < 20 years old who underwent treatment for IAs at our institution between 2005 and 2020. Medical records and imaging were examined for demographic, clinical, and operative data. A systematic review was performed to identify studies reporting primary outcomes of surgical and endovascular treatment of pediatric IAs. Demographic information, aneurysm characteristics, treatment strategies, and outcomes were collected.

RESULTS

Thirty-three patients underwent treatment for 37 aneurysms over 18 years. The mean age was 11.4 years, ranging from one month to 19 years. There were 21 males (63.6%) and 12 females (36.4%), yielding a male: female ratio of 1.75:1. Twenty-six (70.3%) aneurysms arose from the anterior circulation and 11 (29.7%) arose from the posterior circulation. Aneurysmal rupture occurred in 19 (57.5%) patients, of which 8 (24.2%) were categorized as Hunt-Hess grades IV or V. Aneurysm recurrence or rerupture occurred in five (15.2%) patients, and 5 patients (15.2%) died due to sequelae of their aneurysms. Twenty-one patients (63.6%) had a good outcome (modified Rankin Scale score 0-2) on last follow up. The systematic literature review yielded 48 studies which included 1,482 total aneurysms (611 with endovascular treatment; 656 treated surgically; 215 treated conservatively). Mean aneurysm recurrence rates in the literature were 12.7% and 3.9% for endovascular and surgical treatment, respectively.

CONCLUSIONS

Our study provides data on the natural history and longitudinal outcomes for children treated for IAs at a single institution, in addition to our treatment strategies for various aneurysmal morphologies. Despite the high proportion of patients presenting with rupture, good functional outcomes can be achieved for most patients.

Optimizing suction force in mechanical thrombectomy: Priming the aspiration tubing with air versus saline

Objective

We sought to investigate how priming the tube between air versus air mixed with saline ex vivo influenced suction force. We examined how priming the tube influenced peak suction force and time to achieve peak suction force between both modalities.

Methods

Using a Dwyer Instruments (Dwyer Instruments Inc., Michigan City, IN, USA), INC Digitial Pressure Gauge, we were able to connect a .072 inch aspiration catheter to a rotating hemostatic valve and to aspiration tubing. We recorded suction force measured in negative inches of Mercury (inHg) over 10 iterations between having the aspiration tube primed with air alone versus air mixed with saline. A test was used to compare results between both modalities.

Results

Priming the tube with air alone compared to air mixed with saline was found to have an increased average max suction force (-28.60 versus -28.20 in HG, p<0.01). We also identified a logarithmic curve of suction force across time in which time to maximal suction force was more prompt with air compared with air mixed with saline (13.8 seconds versus 21.60 seconds, p<0.01).

Conclusions

Priming the tube with air compared to air mixed with saline suggests that not only is increased maximal suction force achieved, but also the time required to achieve maximal suction force is less. This data suggests against priming the aspiration tubing with saline and suggests that the first pass aspiration primed with air may have the greatest suction force.

Safety of middle meningeal artery embolization for treatment of subdural hematoma: A nationwide propensity score matched analysis

OBJECTIVE

Middle meningeal artery embolization (MMAe) has burgeoned as a treatment for chronic subdural hematoma (cSDH). This study evaluates the safety and short-term outcomes of MMAe patients relative to traditional treatment approaches.

METHODS

In this retrospective large database study, adult patients in the National Inpatient Sample from 2012-2019 with a diagnosis of cSDH were identified. Cost of admission, length of stay (LOS), discharge disposition, and complications were analyzed. Propensity score matching (PSM) was utilized.

RESULTS

A total of 123,350 patients with cSDH were identified: 63,450 without intervention, 59,435 surgery only, 295 MMAe only, and 170 surgery plus MMAe. On PSM analysis, MMAe did not increase the risk of inpatient complications or prolong the length of stay compared to conservative management (p>0.05); MMAe had higher cost ($31,170 vs. $10,768, p<0.001) than conservative management, and a lower rate of nonroutine discharge (53.8% vs. 64.3%, p=0.024). Compared to surgery, MMAe had shorter LOS (5 vs. 7 days, p<0.001), and lower rates of neurological complications (2.7% vs. 7.1%, p=0.029) and nonroutine discharge (53.8% vs. 71.7%, p<0.001). There was no significant difference in cost (p>0.05).

CONCLUSIONS

MMAe had similar LOS and decreased odds of adverse discharge with a modest cost increase compared to conservative management. There was no difference in inpatient complications. Compared to surgery, MMAe treatment was associated with decreased LOS and rates of neurological complications and nonroutine discharge. This nationwide analysis supports the safety of MMAe to treat cSDH.

Characterizing the frequency, morbidity, and types of traumatic brain injuries after the Mexico-San Diego border wall extension: a retrospective cohort review

OBJECTIVE

The aim of this study was to investigate the impact of the US-Mexico border wall height extension on traumatic brain injuries (TBIs) and related costs.

METHODS

In this retrospective cohort study, patients who presented to the UC San Diego Health Trauma Center for injuries from falling at the border wall between 2016 and 2021 were considered. Patients in the pre-height extension period (January 2016-May 2018) were compared with those in the post-height extension period (January 2020-December 2021). Demographic characteristics, clinical data, and hospital charges were analyzed.

RESULTS

A total of 383 patients were identified: 51 (0 TBIs, 68.6% male) in the pre-height extension cohort and 332 (14 TBIs, 77.1% male) in the post-height extension cohort, with mean ages of 33.5 and 31.5 years, respectively. There was an increase in the average number of TBIs per month (0.0 to 0.34) and operative TBIs per month (0.0 to 0.12). TBIs were associated with increased Injury Severity Score (8.8 vs 24.2, p < 0.001), median (IQR) hospital length of stay (5.0 [2-11] vs 8.5 [4-45] days, p = 0.03), and median (IQR) hospital charges ($163,490 [$86,369-$277,918] vs $243,658 [$136,769-$1,127,920], p = 0.04). TBIs were normalized for changing migration rates on the basis of Customs and Border Protection apprehensions.

CONCLUSIONS

This heightened risk of intracranial injury among vulnerable immigrant populations poses ethical and economic concerns to be addressed regarding border wall infrastructure.

The use of robot-assisted surgery for the unstable traumatic spine: A retrospective cohort study

Background

Robotic assistance has been shown to increase instrumentation placement accuracy in open and minimally invasive spinal fusion. These gains have been achieved without increases in operative times, blood loss, or hospitalization duration. However, most work has been done in the degenerative population and little is known of the utility of robotic assistance when applied to spinal trauma. This is largely due to the uncertainty stemming from the disruption of normal anatomy by the traumatic injury. Since the robot depends upon registration for instrumentation guidance according to the fiducials it uses, trauma can introduce unique challenges. The present study sought to evaluate the safety and efficacy of robotic assistance in a consecutive cohort of spine trauma patients.

Methods

All patients with Thoracolumbar Injury Classification and Severity Scale (TLICS) >4 who underwent robot-assisted spinal fusion using the Globus ExcelsiusGPS at a single tertiary care center for trauma between 2020 and 2022 were identified. Demographic, clinical, and surgical data were collected and analyzed; the primary endpoints were operative time, fluoroscopy time, estimated blood loss, postoperative complications, admission time, and 90-day readmission rate. The paired t-test was used to compare differences between mean values when looking at the number of surgical levels.

Results

Forty-two patients undergoing robot-assisted spinal surgery were included (mean age 61.3±17.1 year; 47% female. Patients were stratified by the number of operative levels, 2 (n = 10), 3-4 (n = 11), 5 to 6 (n = 13), or >6 (n = 8). There appeared to be a positive correlation between number of levels instrumented and odds of postoperative complications, admission duration, fluoroscopy time, and estimated blood loss. There were no instances of screw malposition or breach.

Conclusions

This initial experience suggests robotic assistance can be safely employed in the spine trauma population. Additional experiences in larger patient populations are necessary to delineate those traumatic pathologies most amenable to robotic assistance.

Helical coils augment embolization of the middle meningeal artery for treatment of chronic subdural hematoma: A technical note

Embolization of the middle meningeal artery (MMA) is a safe and effective adjunct in the treatment of chronic subdural hematoma. While prior authors describe the use of coils to assist embolization by preventing reflux through eloquent collaterals, we de- scribe the use of coils to further open the MMA, allowing the administration of greater amounts of embolisate for a more robust embolization. The objective of this study was to demonstrate that helical coils can safely open the MMA following the administration of polyvinyl alcohol (PVA) particles. This allows for more embolisate to be administered into the MMA for more effective treatment. A retrospective review was conducted at our institution including intraoperative images and postoperative clinical and radiographic follow up. Failure rates using MMA embolization with PVA and helical coil augmentation were compared to failure rates in the literature of MMA embolization with PVA or ethylene vinyl-alcohol copolymer alone. A total of 8 cases were reviewed in which this technique was implemented. There were no immediate complications after treatment. All patients that underwent helical coil embolization following the administration of PVA had increased amount of embolisate delivered into the MMA. All patients at follow up had resolution of the subdural hematoma on outpatient imaging. Helical coil embolization allows for more embolisate administration into the MMA and provides a technical advantage for patients that fail traditional techniques of embolization. Case series are taking place to further test this hypothesis and identify the ideal patient population that may gain maximal yield from this novel technique.

Viz.ai Implementation of Stroke Augmented Intelligence and Communications Platform to Improve Indicators and Outcomes for a Comprehensive Stroke Center and Network

BACKGROUND AND PURPOSE

Comprehensive stroke centers continually strive to narrow neurointerventional time metrics. Although process improvements have been put in place to streamline workflows, complex pathways, disparate imaging locations, and fragmented communications all highlight the need for continued improvement.

MATERIALS AND METHODS

This Quality Improvement Initiative (VISIION) was implemented to assess our transition to the Viz.ai platform for immediate image review and centralized communication and their effect on key performance indicators in our comprehensive stroke center. We compared periods before and following deployment. Sequential patients having undergone stroke thrombectomy were included. Both direct arriving large-vessel occlusion and Brain Emergency Management Initiative telemedicine transfer large-vessel occlusion cases were assessed as were subgroups of OnHours and OffHours. Text messaging thread counts were compared between time periods to assess communications. Mann-Whitney U and Student t tests were used.

RESULTS

Eighty-two neurointerventional cases were analyzed pre vs. post time periods: (DALVO-OnHours 7 versus 7, DALVO-OffHours 10 versus 5, BEMI-OnHours 13 versus 6, BEMI-OffHours 17 versus 17). DALVO-OffHours had a 39% door-to-groin reduction (157 versus 95 minutes, P = .009). DALVO-All showed a 32% reduction (127 versus 86 minutes, P = .006). BEMI-All improved 33% (42 versus 28 minutes, P = .036). Text messaging thread counts improved 30% (39 versus 27, P = .04).

CONCLUSIONS

There was an immediate improvement following Viz.ai implementation for both direct arriving and telemedicine transfer thrombectomy cases. In the greatest opportunity subset (direct arriving large-vessel occlusion-OffHours: direct arriving cases requiring team mobilization off-hours), we noted a 39% improvement. With Viz.ai, we noted that immediate access to images and streamlined communications improved door-to-groin time metrics for thrombectomy. These results have implications for future care processes and can be a model for centers striving to optimize workflow and improve thrombectomy timeliness.

Racial and ethnic disparities in brain tumour survival by age group and tumour type

PURPOSE

The extent to which racial/ethnic brain tumour survival disparities vary by age is not very clear. In this study, we assess racial/ethnic brain tumour survival disparities overall by age group and type.

METHODS

Data were obtained from the Surveillance, Epidemiology, and End Results (SEER) 18 registries for US-based individuals diagnosed with a first primary malignant tumour from 2007 through 2016. Cox proportional hazards regression was used to compute adjusted hazard ratios (HRs) and 95% confidence intervals (95% CIs) for the association between race/ethnicity and brain tumour survival, stratified by age group and tumour type.

RESULTS

After adjusting for sex, socioeconomic status, insurance status, and tumour type, non-Hispanic (NH) Blacks (HR: 1.26; 95% CI: 1.02-1.55), NH Asian or Pacific Islanders (HR: 1.29; 95% CI: 1.01-1.66), and Hispanics (any race) (HR: 1.28; 95% CI: 1.09-1.51) all showed a survival disadvantage compared with NH Whites for the youngest age group studied (0-9 years). Furthermore, NH Blacks (HR: 0.88; 95% CI: 0.91-0.97), NH Asian or Pacific Islanders (HR: 0.84; 95% CI: 0.77-0.92), and Hispanics (any race) (HR: 0.91; 95% CI: 0.85-0.97) all showed a survival advantage compared with NH Whites for the 60-79 age group. Tests for interactions showed significant trends, indicating that racial/ethnic survival disparities disappear and even reverse for older age groups (P < 0.001). This reversal appears to be driven by poor glioblastoma survival among NH Whites (P < 0.001).

CONCLUSION

Disparities in brain tumour survival among minorities exist primarily among children and adolescents. NH White adults show worse survival than their minority counterparts, which is possibly driven by poor glioblastoma biology.

Application of Antibiotic-Impregnated Polymethyl-Methacrylate Bone Cement for the Treatment of Infected Cranioplasties: Initial Experience

BACKGROUND

Management of infected cranioplasty implants remains a surgical challenge. Surgical debridement, removal of the infected implant, and prolonged antibiotic therapy are part of the acute management. In addition, cranioplasty removal poses the risk of dural tear. Reconstruction of the cranial defect is usually delayed for several months to years, increasing the difficulty due to soft tissue contraction and scarring.

OBJECTIVE

The aim of the study was to propose an alternative to delayed reconstruction in the face of infection with a dual purpose: treat the infection with a material which delivers antibiotic to the area (polymethyl-methacrylate antibiotic) and which functions as a temporary or permanent cranioplasty.

METHODS

We reviewed the records of 3 consecutive patients who underwent single-stage polymethyl-methacrylate antibiotic salvage cranioplasty.

RESULTS

All patients underwent debridement of infected tissue. Titanium mesh was placed over the bony defect. Polymethyl methacrylate impregnated with vancomycin and tobramycin was then spread over the plate and defect before closure. Patients also received extended treatment with systemic antimicrobials. Early outcomes have been encouraging for both cosmesis and treatment of infection.

CONCLUSIONS

Benefits of this treatment strategy include immediate reconstruction rather than staged procedures and delivery of high concentrations of antibiotics directly to the affected area in addition to systemic antibiotics.

Microsurgical Resection of a Giant Posterior Fossa Aneurysmal Malformation in a 21-Month-Old

Pediatric aneurysms commonly occur in the vertebrobasilar circulation with complex morphologies.¹ "Aneurysmal malformations," or fistulous vessel dilations without a nidus, have also been described.² Vessel friability and sensitivity to blood loss can complicate surgery. A 21-month-old male with motor and speech delay was found to have a giant posterior fossa aneurysmal malformation. He was lethargic, with minimal speech, and moved all extremities with mild hypotonia. Imaging demonstrated a 6.9 × 5.1 × 4.6 cm aneurysm arising from a fenestrated right V4 segment. This communicated via a single connection with the deep venous system, draining through the superior vermian cistern veins, posterior mesencephalic vein, basal vein of Galen, and inferior sagittal sinus, consistent with an arteriovenous fistula with secondary aneurysmal dilatation. Endovascular sacrifice was not feasible, in addition to concern for swelling after embolization. Three-dimensional modeling confirmed close proximity of the single inflow and outflow tracts. A suboccipital and left far lateral craniotomy for clip trapping and excision of the aneurysmal arteriovenous malformation was performed in a lateral position to completely decompress the brainstem (Video 1). Angiography before closure and postoperative vascular imaging demonstrated complete aneurysmal resection and fistula disconnection, with patency of normal vasculature. The postoperative course was notable for transient swallowing difficulties likely from lower cranial nerve irritation and refractory hydrocephalus requiring a shunt. The patient was meeting all developmental milestones at 2-year follow-up. This case highlights the complex vascular pathology often seen in pediatric patients, as well as the importance of presurgical planning and careful microsurgical technique in achieving a successful outcome.

Surgical revascularization for Moyamoya disease in the United States: A cost-effectiveness analysis

Objective

Moyamoya disease (MMD) is a vasculopathy of the internal carotid arteries with ischemic and hemorrhagic sequelae. Surgical revascularization confers upfront peri-procedural risk and costs in exchange for long-term protective benefit against hemorrhagic disease. The authors present a cost-effectiveness analysis (CEA) of surgical versus non-surgical management of MMD.

Methods

A Markov Model was used to simulate a 41-year-old suffering a transient ischemic attack (TIA) secondary to MMD and now faced with operative versus nonoperative treatment options. Health utilities, costs, and outcome probabilities were obtained from the CEA registry and the published literature. The primary outcome was incremental cost-effectiveness ratio which compared the quality adjusted life years (QALYs) and costs of surgical and nonsurgical treatments. Base-case, one-way sensitivity, two-way sensitivity, and probabilistic sensitivity analyses were performed with a willingness to pay threshold of $50,000.

Results

The base case model yielded 3.81 QALYs with a cost of $99,500 for surgery, and 3.76 QALYs with a cost of $106,500 for nonsurgical management. One-way sensitivity analysis demonstrated the greatest sensitivity in assumptions to cost of surgery and cost of admission for hemorrhagic stroke, and probabilities of stroke with no surgery, stroke after surgery, poor surgical outcome, and death after surgery. Probabilistic sensitivity analyses demonstrated that surgical revascularization was the cost-effective strategy in over 87.4% of simulations.

Conclusions

Considering both direct and indirect costs and the postoperative QALY, surgery is considerably more cost-effective than non-surgical management for adults with MMD.

Impact of COVID-19 on a Neurosurgical Service: Lessons from the University of California San Diego

Background

The institution-wide response of the University of California San Diego Health system to the 2019 novel coronavirus disease (COVID-19) pandemic was founded on rapid development of in-house testing capacity, optimization of personal protective equipment usage, expansion of intensive care unit capacity, development of analytic dashboards for monitoring of institutional status, and implementation of an operating room (OR) triage plan that postponed nonessential/elective procedures. We analyzed the impact of this triage plan on the only academic neurosurgery center in San Diego County, California, USA.

Methods

We conducted a de-identified retrospective review of all operative cases and procedures performed by the Department of Neurosurgery from November 24, 2019, through July 6, 2020, a 226-day period. Statistical analysis involved 2-sample z tests assessing daily case totals over the 113-day periods before and after implementation of the OR triage plan on March 16, 2020.

Results

The neurosurgical service performed 1429 surgical and interventional radiologic procedures over the study period. There was no statistically significant difference in mean number of daily total cases in the pre–versus post–OR triage plan periods (6.9 vs. 5.8 mean daily cases; 1-tail P = 0.050, 2-tail P = 0.101), a trend reflected by nearly every category of neurosurgical cases.

Conclusions

During the COVID-19 pandemic, the University of California San Diego Department of Neurosurgery maintained an operative volume that was only modestly diminished and continued to meet the essential neurosurgical needs of a large population. Lessons from our experience can guide other departments as they triage neurosurgical cases to meet community needs.

Robot-assisted stereotactic biopsy of pediatric brainstem and thalamic lesions

OBJECTIVE

Biopsies of tumors located in deep midline structures require highly accurate stereotaxy to safely obtain lesional tissue suitable for molecular and histological analysis. Versatile platforms are needed to meet a broad range of technical requirements and surgeon preferences. The authors present their institutional experience with the robotic stereotactic assistance (ROSA) system in a series of robot-assisted biopsies of pediatric brainstem and thalamic tumors.

METHODS

A retrospective analysis was performed of 22 consecutive patients who underwent 23 stereotactic biopsies of brainstem or thalamic lesions using the ROSA platform at Rady Children's Hospital in San Diego between December 2015 and January 2020.

RESULTS

The ROSA platform enabled rapid acquisition of lesional tissue across various combinations of approaches, registration techniques, and positioning. No permanent deficits, major adverse outcomes, or deaths were encountered. One patient experienced temporary cranial neuropathy, and 3 developed small asymptomatic hematomas. The diagnostic success rate of the ROSA system was 91.3%.

CONCLUSIONS

Robot-assisted stereotactic biopsy of these lesions may be safely performed using the ROSA platform. This experience comprises the largest clinical series to date dedicated to robot-assisted biopsies of brainstem and diencephalic tumors.

Prone Transpsoas Technique for Simultaneous Single-Position Access to the Anterior and Posterior Lumbar Spine

BACKGROUND

Effective decompression, arthrodesis, and correction of spinal conditions frequently utilize operative approaches that expose both the anterior and posterior spinal column. Until now, circumferential spinal column access often requires the surgeon to reposition and drape the patient multiple times or utilize a posterior only approach that has limited anterior correction capability or to utilize a lateral-only approach that complicates otherwise traditional posterior surgical maneuvers.

OBJECTIVE

To describe a technique utilizing a single surgical position that enables minimally disruptive anterior column correction with simultaneous access to the posterior spinal column.

METHODS

The operative technique for accessing the lateral lumbar interbody space from a prone transpsoas (PTP) approach is described. The rationale for this approach and a representative case example are reviewed.

RESULTS

The PTP approach was used to perform an L3-4 and L4-5 interbody fusion in a 71-yr-old female with spondylolisthesis, severe stenosis, and locked facets. The PTP approach enabled efficient completion of an anterior column correction, direct posterior decompression, multi-segment pedicle fixation, and maintenance of alignment, all while in a single prone position. There were no intraoperative or postoperative complications.

CONCLUSION

The authors’ early experience with the described PTP technique suggests it is not only feasible but offers some advantages, as it allows for single-position surgery maximizing both anterior and posterior column access and corrective techniques. Further follow-up studies of this technique are ongoing.

First-in-Man Clinical Experience Using a High-Definition 3-Dimensional Exoscope System for Microneurosurgery

BACKGROUND

During its development and preclinical assessment, a novel, 3-dimensional (3D), high-definition (4K-HD) exoscope system was formerly shown to provide an immersive surgical experience, while maintaining a portable, low-profile design.

OBJECTIVE

To assess the clinical applicability of this 3D 4K-HD exoscope via first-in-man surgical use.

METHODS

The operative workflow, functionality, and visual haptics of the 3D 4K-HD exoscope were assessed in a variety of microneurosurgical cases at 2 US centers.

RESULTS

Nineteen microneurosurgical procedures in 18 patients were performed exclusively using the 3D 4K-HD exoscope. Pathologies treated included 4 aneurysms, 3 cavernous malformations (1 with intraoperative electrocorticography), 2 arteriovenous malformations, 1 foramen magnum meningioma, 1 convexity meningioma, 1 glioma, 1 occipital cyst, 1 chiari malformation, 1 carotid endarterectomy, 1 subdural hematoma, 1 anterior cervical discectomy and fusion, and 2 lumbar laminectomies. All patients experienced good surgical and clinical outcomes. Similar to preclinical assessments, the 3D 4K-HD exoscope provided an immersive 3D surgical experience for the primary surgeon, assistants, and trainees. The small exoscope frame, large depth of field, and hand/foot pedal controls improved exoscope mobility, decreased need to re-focus, and provided unobstructed operative corridors. Flexible positioning of the camera allows the surgeon's posture to be kept in a neutral position with uncompromised viewing angles.

CONCLUSION

The first-in-man clinical experience with the 3D 4K-HD exoscope confirms its excellent optics and ergonomics for the entire operative team, with high workflow adaptability for a variety of microneurosurgical cases. Expanded clinical use of the 3D 4K-HD exoscope is justified.

Role of pregnancy and female sex steroids on aneurysm formation, growth, and rupture: a systematic review of the literature

OBJECTIVE

Women have been shown to have a higher risk of cerebral aneurysm formation, growth, and rupture than men. The authors present a review of the recently published neurosurgical literature that studies the role of pregnancy and female sex steroids, to provide a conceptual framework with which to understand the various risk factors associated with cerebral aneurysms in women at different stages in their lives.

METHODS

The PubMed database was searched for "("intracranial" OR "cerebral") AND "aneurysm" AND ("pregnancy" OR "estrogen" OR "progesterone")" between January 1980 and February 2019. A total of 392 articles were initially identified, and after applying inclusion and exclusion criteria, 20 papers were selected for review and analysis. These papers were then divided into two categories: 1) epidemiological studies about the formation, growth, rupture, and management of cerebral aneurysms in pregnancy; and 2) investigations on female sex steroids and cerebral aneurysms (animal studies and epidemiological studies).

RESULTS

The 20 articles presented in this study include 7 epidemiological articles on pregnancy and cerebral aneurysms, 3 articles reporting case series of cerebral aneurysms treated by endovascular therapies in pregnancy, 3 epidemiological articles reporting the relationship between female sex steroids and cerebral aneurysms through retrospective case-control studies, and 7 experimental studies using animal and/or cell models to understand the relationship between female sex steroids and cerebral aneurysms. The studies in this review report similar risk of aneurysm rupture in pregnant women compared to the general population. Most ruptured aneurysms in pregnancy occur during the 3rd trimester, and most pregnant women who present with cerebral aneurysm have caesarean section deliveries. Endovascular treatment of cerebral aneurysms in pregnancy is shown to provide a new and safe form of therapy for these cases. Epidemiological studies of postmenopausal women show that estrogen hormone therapy and later age at menopause are associated with a lower risk of cerebral aneurysm than in matched controls. Experimental studies in animal models corroborate this epidemiological finding; estrogen deficiency causes endothelial dysfunction and inflammation, which may predispose to the formation and rupture of cerebral aneurysms, while exogenous estrogen treatment in this population may lower this risk.

CONCLUSIONS

The aim of this work is to equip the neurosurgical and obstetrical/gynecological readership with the tools to better understand, critique, and apply findings from research on sex differences in cerebral aneurysms.

Simulator Training for Endovascular Neurosurgery

Simulation-based training has become common practice across medical specialties, especially for learning complex skills performed in high-risk environments. In the field of endovascular neurosurgery, the demand for consequence- and risk-free learning environments led to the development of simulation devices valuable for medical trainees. The goal of this protocol is to provide instructive guidelines for the use of an endovascular neurosurgery simulator in an academic setting. The simulator provides trainees with the opportunity to receive realistic feedback on their knowledge of anatomy, as well as haptic feedback indicative of their success in handling the catheter-based systems without negative consequences. The utility of this specific protocol in relation to other neuroendovascular training modalities is also discussed.

Epidemiology, Natural History, and Clinical Presentation of Large Vessel Ischemic Stroke

Large vessel occlusions (LVOs), variably defined as blockages of the proximal intracranial anterior and posterior circulation, account for approximately 24% to 46% of acute ischemic strokes. Commonly refractory to intravenous tissue plasminogen activator (tPA), LVOs place large cerebral territories at ischemic risk and cause high rates of morbidity and mortality without further treatment. Over the past few years, an abundance of high-quality data has demonstrated the efficacy of endovascular thrombectomy for improving clinical outcomes in patients with LVOs, transforming the treatment algorithm for affected patients. In this review, we discuss the epidemiology, pathophysiology, natural history, and clinical presentation of LVOs as a framework for understanding the recent clinical strides of the endovascular era.

Antiplatelet therapy within 24 hours of tPA: lessons learned from patients requiring combined thrombectomy and stenting for acute ischemic stroke

Objective

Although stroke guidelines recommend antiplatelets be started 24 hours after tissue plasminogen activator (tPA), select mechanical thrombectomy (MT) patients with luminal irregularities or underlying intracranial atherosclerotic disease may benefit from earlier antiplatelet administration.

Methods

We explore the safety of early (<24 hours) post-tPA antiplatelet use by retrospectively reviewing patients who underwent MT and stent placement for acute ischemic stroke from June 2015 to April 2018 at our institution.

Results

Six patients met inclusion criteria. Median presenting and pre-operative National Institutes of Health Stroke Scale scores were 14 (Interquartile Range [IQR] 5.5–17.3) and 16 (IQR 13.7–18.7), respectively. Five patients received standard intravenous (IV) tPA and one patient received intra-arterial tPA. Median time from symptom onset to IV tPA was 120 min (IQR 78–204 min). Median time between tPA and antiplatelet administration was 4.9 hours (IQR 3.0–6.7 hours). Clots were successfully removed from the internal carotid artery (ICA) or middle cerebral artery (MCA) in 5 patients, the anterior cerebral artery (ACA) in one patient, and the vertebrobasilar junction in one patient. All patients underwent MT before stenting and achieved thrombolysis in cerebral infarction 2B recanalization. Stents were placed in the ICA (n=4), common carotid artery (n=1), and basilar artery (n=1). The median time from stroke onset to endovascular access was 185 min (IQR 136–417 min). No patients experienced symptomatic post-procedure intracranial hemorrhage (ICH). Median modified Rankin Scale score on discharge was 3.5.

Conclusions

Antiplatelets within 24 hours of tPA did not result in symptomatic ICH in this series. The safety and efficacy of early antiplatelet administration after tPA in select patients following mechanical thrombectomy warrants further study.

The effect of hospital safety-net burden on outcomes, cost, and reportable quality metrics after emergent clipping and coiling of ruptured cerebral aneurysms

OBJECTIVE

Safety-net hospitals deliver care to a substantial share of vulnerable patient populations and are disproportionately impacted by hospital payment reform policies. Complex elective procedures performed at safety-net facilities are associated with worse outcomes and higher costs. The effects of hospital safety-net burden on highly specialized, emergent, and resource-intensive conditions are poorly understood. The authors examined the effects of hospital safety-net burden on outcomes and costs after emergent neurosurgical intervention for ruptured cerebral aneurysms.

METHODS

The authors conducted a retrospective analysis of the Nationwide Inpatient Sample (NIS) from 2002 to 2011. Patients ≥ 18 years old who underwent emergent surgical clipping and endovascular coiling for aneurysmal subarachnoid hemorrhage (SAH) were included. Safety-net burden was defined as the proportion of Medicaid and uninsured patients treated at each hospital included in the NIS database. Hospitals that performed clipping and coiling were stratified as low-burden (LBH), medium-burden (MBH), and high-burden (HBH) hospitals.

RESULTS

A total of 34,647 patients with ruptured cerebral aneurysms underwent clipping and 23,687 underwent coiling. Compared to LBHs, HBHs were more likely to treat black, Hispanic, Medicaid, and uninsured patients (p < 0.001). HBHs were also more likely to be associated with teaching hospitals (p < 0.001). No significant differences were observed among the burden groups in the severity of subarachnoid hemorrhage. After adjusting for patient demographics and hospital characteristics, treatment at an HBH did not predict in-hospital mortality, poor outcome, length of stay, costs, or likelihood of a hospital-acquired condition.

CONCLUSIONS

Despite their financial burden, safety-net hospitals provide equitable care after surgical clipping and endovascular coiling for ruptured cerebral aneurysms and do not incur higher hospital costs. Safety-net hospitals may have the capacity to provide equitable surgical care for highly specialized emergent neurosurgical conditions.

The Potential Impact of "Take the Volume Pledge" on Outcomes After Carotid Artery Stenting

BACKGROUND

The "Volume Pledge" aims to centralize carotid artery stenting (CAS) to hospitals and surgeons performing ≥10 and ≥5 procedures annually, respectively.

OBJECTIVE

To compare outcomes after CAS between hospitals and surgeons meeting or not meeting the Volume Pledge thresholds.

METHODS

We queried the Nationwide Inpatient Sample for CAS admissions. Hospitals and surgeons were categorized as low volume and high volume (HV) based on the Volume Pledge. Multivariable hierarchical regression models were used to examine the impact of hospital volume (2005-2011) and surgeon volume (2005-2009) on perioperative outcomes.

RESULTS

Between 2005 and 2011, 22 215 patients were identified. Most patients underwent CAS by HV hospitals (86.4%). No differences in poor outcome (composite endpoint of in-hospital mortality, postoperative neurological or cardiac complications) were observed by hospital volume but HV hospitals did decrease the likelihood of other complications, nonroutine discharge, and prolonged hospitalization. From 2005 to 2009, 9454 CAS admissions were associated with physician identifiers. Most patients received CAS by HV surgeons (79.2%). On multivariable analysis, hospital volume was not associated with improved outcomes but HV surgeons decreased odds of poor outcome (odds ratio [OR] 0.76, 95% confidence interval [CI] 0.59-0.97; P = .028), complications (OR 0.56, 95% CI 0.46-0.71, P < .001), nonroutine discharge (OR 0.70, 95% CI 0.57-0.87; P = .001), and prolonged hospitalization (OR 0.52, 95% 0.44-0.61, P < .001).

CONCLUSION

Most patients receive CAS by hospitals and providers meeting the Volume Pledge threshold for CAS. Surgeons but not hospitals who met the policy's volume standards were associated with superior outcomes across all measured outcomes.

Clinical and genetic characterization of patients with Pierre Robin sequence and spinal disease: review of the literature and novel terminal 10q deletion

INTRODUCTION

The Pierre-Robin sequence (PRS) is a pattern of congenital facial abnormalities comprising micrognathia, glossoptosis, and airway obstruction. Associated spinal pathologies have rarely been reported with PRS.

METHODS

We explore the molecular genetic basis of this association through a systematic review of spinal disease in patients with PRS. We also present an illustrative case of a PRS patient with tethered cord in the setting of chromosome 10q terminal deletion.

RESULTS

Our systematic literature review of spinal disease in patients with PRS revealed several patterns in the underlying genetic syndromes causing these conditions to co-occur. These principles are illustrated in the case of a 6-month-old female with PRS and a 14.34-Mb terminal deletion of chromosome 10q, who was found to have a sacral dimple during a routine outpatient checkup. Magnetic resonance imaging of the spine revealed a lumbar syrinx associated with tethered spinal cord. Surgical de-tethering was undertaken, with subsequent improvement in motor function and decrease in the size of the syrinx. The deletion of chromosome 10q in our patient had not previously been described in association with tethered cord or PRS.

CONCLUSION

Spinal pathologies are understudied contributors to disease burden in patients with PRS. The range of predisposing syndromes and mutations in patients with both PRS and spinal disorders remains poorly characterized but may be more defined than previously conceived. Clinical screening is most critical during neonatal and adolescent developmental periods with continued neurological assessment. This study emphasizes the need for early genetic testing and counseling in this patient population, in parallel with research efforts to develop molecular classifications to guide clinical management.

Risk Factors for Urinary Tract Infection or Pneumonia After Admission for Traumatic Subdural Hematoma at a Level I Trauma Center: Large Single-Institution Series

BACKGROUND

The development of infections such as urinary tract infections (UTIs) or pneumonia after a traumatic subdural hematoma (tSDH) can worsen patient outcomes and increase healthcare costs. We herein identify clinical parameters that influence the risk of infections after tSDH.

METHODS

This single-institution retrospective cohort study examined the incidence and risk factors for UTI and pneumonia among tSDH patients from 1990 to 2015. Multivariate logistic regression assessed the impact of various demographic and clinical variables on these outcomes.

RESULTS

3024 patients with tSDHs were identified (73.1% male); Of those, 208 (6.9%) experienced a UTI and 434 (14.4%) experienced pneumonia. Of the 559 patients (18.5%) who underwent a craniotomy and/or craniectomy for evacuation of a tSDH, 62 (11.1%) experienced a UTI and 222 (39.7%) experienced pneumonia. Risk factors for both pneumonia and UTI included length of stay (LOS) ≥7 days (odds ratio [OR] = 6.0, P < 0.001; OR = 11.2, P < 0.001), intensive care unit LOS ≥7 days (OR = 8.1, P < 0.001; OR = 1.7, P = 0.012), and mechanical ventilation ≥14 days (OR = 3.4, P < 0.001; OR = 1.8, P = 0.007). Craniotomy/craniectomy increased the risk of pneumonia (OR = 1.4, P = 0.019) but not UTI. Glasgow Coma Scale (GCS) ≥13 was associated with a decreased pneumonia risk (OR = 0.5, P = 0.003), and male gender (OR = 0.5, P < 0.001) and age <60 (OR = 0.6, P < 0.001) were associated with a decreased UTI risk.

CONCLUSIONS

Patients with prolonged hospitalizations and/or intensive care unit stays were more likely to experience UTIs and pneumonia. Male gender and younger age were protective against UTI, and higher GCS was protective against pneumonia. These data may aid the identification and treatment of at-risk populations after admission for a tSDH.

Markov modeling for the neurosurgeon: a review of the literature and an introduction to cost-effectiveness research

OBJECTIVE Markov modeling is a clinical research technique that allows competing medical strategies to be mathematically assessed in order to identify the optimal allocation of health care resources. The authors present a review of the recently published neurosurgical literature that employs Markov modeling and provide a conceptual framework with which to evaluate, critique, and apply the findings generated from health economics research. METHODS The PubMed online database was searched to identify neurosurgical literature published from January 2010 to December 2017 that had utilized Markov modeling for neurosurgical cost-effectiveness studies. Included articles were then assessed with regard to year of publication, subspecialty of neurosurgery, decision analytical techniques utilized, and source information for model inputs. RESULTS A total of 55 articles utilizing Markov models were identified across a broad range of neurosurgical subspecialties. Sixty-five percent of the papers were published within the past 3 years alone. The majority of models derived health transition probabilities, health utilities, and cost information from previously published studies or publicly available information. Only 62% of the studies incorporated indirect costs. Ninety-three percent of the studies performed a 1-way or 2-way sensitivity analysis, and 67% performed a probabilistic sensitivity analysis. A review of the conceptual framework of Markov modeling and an explanation of the different terminology and methodology are provided. CONCLUSIONS As neurosurgeons continue to innovate and identify novel treatment strategies for patients, Markov modeling will allow for better characterization of the impact of these interventions on a patient and societal level. The aim of this work is to equip the neurosurgical readership with the tools to better understand, critique, and apply findings produced from cost-effectiveness research.

Neurosurgical Management of a Thoracic Dorsal Arachnoid Web: Case Illustration

Dorsal thoracic arachnoid webs are rare clinical entities caused by a thickened intradural extramedullary band of arachnoid tissue that compresses the spinal cord, and often present with progressive back pain, paresthesias, and lower extremity weakness. In this report, we review the radiographic features of the “Scalpel Sign” and describe the case of a 47-year-old male that failed conservative therapy and was found to have dorsal thoracic arachnoid web. The patient underwent laminectomy and microsurgical release of the compressing arachnoid band. Postoperatively, the patient had complete resolution of his pain. Intraoperatively, the somatosensory evoked potentials were improved once the band was released. The prompt diagnosis of dorsal arachnoid webs remains critical because surgical treatment arrests and potentially reverses the pathology.

Cost-effectiveness of Intraoperative MRI for Treatment of High-Grade Gliomas

Background Intraoperative MRI has been shown to improve gross-total resection of high-grade glioma. However, to the knowledge of the authors, the cost-effectiveness of intraoperative MRI has not been established. Purpose To construct a clinical decision analysis model for assessing intraoperative MRI in the treatment of high-grade glioma. Materials and Methods An integrated five-state microsimulation model was constructed to follow patients with high-grade glioma. One-hundred-thousand patients treated with intraoperative MRI were compared with 100 000 patients who were treated without intraoperative MRI from initial resection and debulking until death (median age at initial resection, 55 years). After the operation and treatment of complications, patients existed in one of three health states: progression-free survival (PFS), progressive disease, or dead. Patients with recurrence were offered up to two repeated resections. PFS, valuation of health states (utility values), probabilities, and costs were obtained from randomized controlled trials whenever possible. Otherwise, national databases, registries, and nonrandomized trials were used. Uncertainty in model inputs was assessed by using deterministic and probabilistic sensitivity analyses. A health care perspective was used for this analysis. A willingness-to-pay threshold of $100 000 per quality-adjusted life year (QALY) gained was used to determine cost efficacy. Results Intraoperative MRI yielded an incremental benefit of 0.18 QALYs (1.34 QALYs with intraoperative MRI vs 1.16 QALYs without) at an incremental cost of $13 447 ($176 460 with intraoperative MRI vs $163 013 without) in microsimulation modeling, resulting in an incremental cost-effectiveness ratio of $76 442 per QALY. Because of parameter distributions, probabilistic sensitivity analysis demonstrated that intraoperative MRI had a 99.5% chance of cost-effectiveness at a willingness-to-pay threshold of $100 000 per QALY. Conclusion Intraoperative MRI is likely to be a cost-effective modality in the treatment of high-grade glioma. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Bettmann in this issue.

Endovascular Flow Diversion for Hemifacial Spasm Induced by a Vertebral Artery Aneurysm: First Experience

BACKGROUND AND IMPORTANCE

Flow diversion for the treatment of aneurysm-induced hemifacial spasm (HFS) has not been previously described.

CLINICAL PRESENTATION

The authors present the case of a 60-yr-old woman who presented with 1 yr of progressive left HFS secondary to a vertebral artery aneurysm compressing the root entry zone of cranial nerve VII. The patient's aneurysm was successfully treated with a flow diverting stent.

CONCLUSION

In the immediate postoperative period, the patient had near complete resolution of her HFS symptoms. At her 6-mo follow-up the patient had no angiographic filling of the aneurysm and her HFS symptoms had completely resolved.

The impact of traveling distance and hospital volume on post-surgical outcomes for patients with glioblastoma

BACKGROUND

High-volume hospitals are associated with improved outcomes in glioblastoma (GBM). However, the impact of travel burden to high-volume centers is poorly understood. We examined post-operative outcomes between GBM patients that underwent treatment at local, low-volume hospitals with those that traveled long distances to high-volume hospitals.

METHODS

The National Cancer Database was queried for GBM patients that underwent surgery (2010-2014). We established two cohorts: patients in the lowest quartile of travel distance and volume (Short-travel/Low-Volume: STLV) and patients in the highest quartile of travel and volume (Long-travel/High-Volume: LTHV). Outcomes analyzed were 30-day, 90-day mortality, overall survival, 30-day readmission, and hospital length of stay.

RESULTS

Of 35,529 cases, STLV patients (n = 3414) traveled a median of 3 miles (Interquartile range [IQR] 1.8-4.2) to low-volume centers (5 [3-7] annual cases) and LTHV patients (n = 3808) traveled a median of 62 miles [44.1-111.3] to high-volume centers (48 [42-71]). LTHV patients were younger, had lower Charlson scores, largely received care at academic centers (84.4% vs 11.9%), were less likely to be minorities (8.1% vs 17.1%) or underinsured (6.9% vs 12.1), and were more likely to receive trimodality therapy (75.6% vs 69.2%; all p < 0.001). On adjusted analysis, LTHV predicted improved overall survival (HR 0.87, p = 0.002), decreased 90-day mortality (OR 0.72, p = 0.019), lower 30-day readmission (OR 0.42, p < 0.001), and shorter hospitalizations (RR 0.79, p < 0.001).

CONCLUSIONS

Glioblastoma patients who travel farther to high-volume centers have superior post-operative outcomes compared to patients who receive treatment locally at low-volume centers. Strategies that facilitate patient travel to high-volume hospitals may improve outcomes.

Nerve transfer versus muscle transfer to restore elbow flexion after pan-brachial plexus injury: a cost-effectiveness analysis

OBJECTIVE Pan-brachial plexus injury (PBPI), involving C5-T1, disproportionately affects young males, causing lifelong disability and decreased quality of life. The restoration of elbow flexion remains a surgical priority for these patients. Within the first 6 months of injury, transfer of spinal accessory nerve (SAN) fascicles via a sural nerve graft or intercostal nerve (ICN) fascicles to the musculocutaneous nerve can restore elbow flexion. Beyond 1 year, free-functioning muscle transplantation (FFMT) of the gracilis muscle can be used to restore elbow flexion. The authors present the first cost-effectiveness model to directly compare the different treatment strategies available to a patient with PBPI. This model assesses the quality of life impact, surgical costs, and possible income recovered through restoration of elbow flexion. METHODS A Markov model was constructed to simulate a 25-year-old man with PBPI without signs of recovery 4.5 months after injury. The management options available to the patient were SAN transfer, ICN transfer, delayed FFMT, or no treatment. Probabilities of surgical success rates, quality of life measurements, and disability were derived from the published literature. Cost-effectiveness was defined using incremental cost-effectiveness ratios (ICERs) defined by the ratio between costs of a treatment strategy and quality-adjusted life years (QALYs) gained. A strategy was considered cost-effective if it yielded an ICER less than a willingness-to-pay of $50,000/QALY gained. Probabilistic sensitivity analysis (PSA) was performed to address parameter uncertainty. RESULTS The base case model demonstrated a lifetime QALYs of 22.45 in the SAN group, 22.0 in the ICN group, 22.3 in the FFMT group, and 21.3 in the no-treatment group. The lifetime costs of income lost through disability and interventional/rehabilitation costs were $683,400 in the SAN group, $727,400 in the ICN group, $704,900 in the FFMT group, and $783,700 in the no-treatment group. Each of the interventional modalities was able to dramatically improve quality of life and decrease lifelong costs. A Monte Carlo PSA demonstrated that at a willingness-to-pay of $50,000/QALY gained, SAN transfer dominated in 88.5% of iterations, FFMT dominated in 7.5% of iterations, ICN dominated in 3.5% of iterations, and no treatment dominated in 0.5% of iterations. CONCLUSIONS This model demonstrates that nerve transfer surgery and muscle transplantation are cost-effective strategies in the management of PBPI. These reconstructive neurosurgical modalities can improve quality of life and lifelong earnings through decreasing disability.

Pipeline embolization device versus coiling for the treatment of large and giant unruptured intracranial aneurysms: a cost-effectiveness analysis

OBJECTIVE Rupture of large or giant intracranial aneurysms leads to significant morbidity, mortality, and health care costs. Both coiling and the Pipeline embolization device (PED) have been shown to be safe and clinically effective for the treatment of unruptured large and giant intracranial aneurysms; however, the relative cost-to-outcome ratio is unknown. The authors present the first cost-effectiveness analysis to compare the economic impact of the PED compared with coiling or no treatment for the endovascular management of large or giant intracranial aneurysms. METHODS A Markov model was constructed to simulate a 60-year-old woman with a large or giant intracranial aneurysm considering a PED, endovascular coiling, or no treatment in terms of neurological outcome, angiographic outcome, retreatment rates, procedural and rehabilitation costs, and rupture rates. Transition probabilities were derived from prior literature reporting outcomes and costs of PED, coiling, and no treatment for the management of aneurysms. Cost-effectiveness was defined, with the incremental cost-effectiveness ratios (ICERs) defined as difference in costs divided by the difference in quality-adjusted life years (QALYs). The ICERs < $50,000/QALY gained were considered cost-effective. To study parameter uncertainty, 1-way, 2-way, and probabilistic sensitivity analyses were performed. RESULTS The base-case model demonstrated lifetime QALYs of 12.72 for patients in the PED cohort, 12.89 for the endovascular coiling cohort, and 9.7 for patients in the no-treatment cohort. Lifetime rehabilitation and treatment costs were $59,837.52 for PED; $79,025.42 for endovascular coiling; and $193,531.29 in the no-treatment cohort. Patients who did not undergo elective treatment were subject to increased rates of aneurysm rupture and high treatment and rehabilitation costs. One-way sensitivity analysis demonstrated that the model was most sensitive to assumptions about the costs and mortality risks for PED and coiling. Probabilistic sampling demonstrated that PED was the cost-effective strategy in 58.4% of iterations, coiling was the cost-effective strategy in 41.4% of iterations, and the no-treatment option was the cost-effective strategy in only 0.2% of iterations. CONCLUSIONS The authors' cost-effective model demonstrated that elective endovascular techniques such as PED and endovascular coiling are cost-effective strategies for improving health outcomes and lifetime quality of life measures in patients with large or giant unruptured intracranial aneurysm.

Impact of preoperative endovascular embolization on immediate meningioma resection outcomes

OBJECTIVE

Preoperative embolization of meningiomas can facilitate their resection when they are difficult to remove. The optimal use and timing of such a procedure remains controversial given the risk of embolization-linked morbidity in select clinical settings. In this work, the authors used a large national database to study the impact of immediate preoperative embolization on the immediate outcomes of meningioma resection.

METHODS

Meningioma patients who had undergone elective resection were identified in the National (Nationwide) Inpatient Sample (NIS) for the period 2002–2014. Patients who had undergone preoperative embolization were propensity score matched to those who had not, adjusting for patient and hospital characteristics. Associations between preoperative embolization and morbidity, mortality, and nonroutine discharge were investigated.

RESULTS

Overall, 27,008 admissions met the inclusion criteria, and 633 patients (2.34%) had undergone preoperative embolization and 26,375 (97.66%) had not. The embolization group was younger (55.17 vs 57.69 years, p < 0.001) with a lower proportion of females (63.5% vs 69.1%, p = 0.003), higher Charlson Comorbidity Index (p = 0.002), and higher disease severity (p < 0.001). Propensity score matching retained 413 embolization and 413 nonembolization patients. In the matched cohort, preoperative embolization was associated with increased rates of cerebral edema (25.2% vs 17.7%, p = 0.009), posthemorrhagic anemia or transfusion (21.8% vs 13.8%, p = 0.003), and nonroutine discharge (42.8% vs 35.7%, p = 0.039). There was no difference in mortality (≤ 2.4% vs ≤ 2.4%, p = 0.82). Among the embolization patients, the mean interval from embolization to resection was 1.49 days. On multivariate analysis, a longer interval was significantly associated with nonroutine discharge (OR 1.33, p = 0.004) but not with complications or mortality.

CONCLUSIONS

Relative to meningioma patients who do not undergo preoperative embolization in the same admission, those who do have higher rates of cerebral edema and nonroutine discharge but not higher rates of stroke or death. Thus, meningiomas requiring preoperative embolization represent a distinct clinical entity that requires prolonged, more complex care. Further, among embolization patients, the timing of resection did not affect the risk of in-hospital complications, suggesting that the timing of surgery can be determined according to surgeon discretion.

Improving Door to Groin Puncture Time for Mechanical Thrombectomy via Iterative Quality Protocol Interventions

Introduction: Delays in door to groin puncture time (DGPT) for patients with ischemic stroke caused by acute large vessel occlusions (LVO) are associated with worse clinical outcomes. We present the results of a quality improvement protocol for endovascular stroke treatment at the University of California, San Diego (UCSD) that aimed to minimize DGPT.

Materials and Methods: Our stroke team implemented a series of quality improvement measures to decrease DGPT, with a target of 90 minutes or less. Sixty-three patients treated at our center were retrospectively divided into three groups based on the date of their intervention as a proxy for the implementation of process improvement protocols: 23 patients treated from July to December 2015, 24 patients treated from January to July 2016, and 16 patients treated from July 2016 to December 2016. Multivariate log-linear and logistic regression analyses were used to assess the predictors of prolonged DGPT and compliance with target DGPT (<90 min), respectively.

Results: Date of intervention—a proxy for the implementation of process improvement protocols—was predictive of compliance with target DGPT. Patients treated from July 2016 to December 2016—after the full implementation of process improvements—were 3.2 times more likely to meet or exceed the target DGPT compared to patients treated from July 2015 to December 2015 (p=0.011). When adjusting for potential confounders in a multivariate analysis, patients in the final cohort were associated with shorter DGPT (Exp(B)=0.61, p=0.013) and remained significantly more likely to achieve the DGPT goal (OR=14.2, p=0.007).

Conclusion: An iterative quality improvement process can significantly improve DGPT. This analysis demonstrates the utility of a formal quality improvement system at an academic comprehensive stroke center.

Comprehensive Endovascular and Open Surgical Management of Cerebral Arteriovenous Malformations

Arteriovenious malformations (AVMs) are associated with significant morbidity and mortality, and have a rupture risk of ~3% per year. Treatment of AVMs must be tailored specifically to the lesion, with surgical resection being the gold standard for small, accessible lesions. Pre-operative embolization of AVMs can reduce nidal blood flow and remove high-risk AVM features such as intranidal or venous aneurysms, thereby simplifying a challenging neurosurgical procedure. Herein, we describe our approach for the staged endovascular embolization and open resection of AVMs, and highlight the advantages of having a comprehensively trained neurovascular surgeon leading a multi-disciplinary clinical team. This includes planning the craniotomy and resection to immediately follow the final embolization stage, thereby using a single session of anesthesia for aggressive embolization, and rapid resection. Finally, we provide a representative case of a 22-year-old female with an unruptured right frontal AVM diagnosed during a seizure workup, who was successfully treated via staged embolizations followed by open surgical resection.

Spinal Shortening for Recurrent Tethered Cord Syndrome via a Lateral Retropleural Approach: A Novel Operative Technique

Spine shortening via vertebral osteotomy (SSVO) for recurrent tethered cord syndrome (TCS) is a novel surgical technique that avoids the complication profile associated with revision detethering. While SSVO has previously been described via a posterior approach, we describe a lateral retropleural approach for SSVO in recurrent TCS in a 21-year-old female.

Our patient presented with progressive lower extremity weakness, bowel and bladder incontinence, and back pain in the setting of childhood repair of myelomeningocele and two previous detethering procedures. SSVO was offered to the patient as further detethering was deemed to have significant risk. A discectomy at T11-T12 via the lateral retropleural approach was performed, followed by a T12 partial corpectomy removing the vertebral body down to the inferior aspect of the T12 pedicle, followed by the removal of the ipsilateral pedicle. The T10, T11, L1, and L2 pedicle screws were then placed in the prone position and temporary rods were placed for temporary stability, followed by a laminectomy at T12 and a facetectomy for posterior element release. The remaining pedicle was removed, permanent rods were sequentially placed, and spinal column shortening was achieved by compression against the rods. Standing lateral radiographs demonstrated 19 millimeters (mm) of shortening after the intervention. The patient remained at her neurologic baseline postoperatively. At the six-month follow-up, the patient reported decreased lower extremity radicular pain and improved bowel and bladder function.

This operative report demonstrates that SSVO via a lateral retropleural approach is a viable treatment for the recurrence of TCS. The advantages of this minimally invasive approach compared to the posterior approach are direct access to the vertebral body and disc space, avoiding the need to operate around the spinal cord. Further studies are necessary to assess this minimally invasive approach to spinal shortening and to see if a complete minimally invasive approach is possible.

Vessel wall signal enhancement on 3-T MRI in acute stroke patients after stent retriever thrombectomy

OBJECTIVE In vivo and in vitro studies have demonstrated histological evidence of iatrogenic endothelial injury after stent retriever thrombectomy. However, noncontrast vessel wall (VW)-MRI is insufficient to demonstrate vessel injury. Authors of this study prospectively evaluated iatrogenic endothelial damage after stent retriever thrombectomy in humans by utilizing high-resolution contrast-enhanced VW-MRI. Characterization of VW-MRI changes in vessels subject to mechanical injury from thrombectomy may allow better understanding of the biological effects of this intervention. METHODS The authors prospectively recruited 11 patients for this study. The treatment group included 6 postthrombectomy patients and the control group included 5 subjects undergoing MRI for nonvascular indications. All subjects were evaluated on a Signa HD× 3.0-T MRI scanner with an 8-channel head coil. Both pre- and postcontrast T1-weighted Cube VW images as well as MR angiograms were acquired. Sequences obtained for evaluation of the brain parenchyma included diffusion-weighted, gradient echo, and T2-FLAIR imaging. Two independent neuroradiologists, who were blinded to the treatment status of each patient, determined the presence of VW enhancement. Patient age, National Institutes of Health Stroke Scale score on presentation, location of occlusion, stroke etiology, type of device used, number of device deployments, Thrombolysis in Cerebral Infarction (TICI) reperfusion score, stroke volume, and 90-day modified Rankin Scale score were also noted. RESULTS Postcontrast T1-weighted VW enhancement was detected in the M₂ segment in 100% of the thrombectomy patients, in the M₁ segment in 83%, and in the internal carotid artery in 50%. One patient also demonstrated A₁ segment enhancement, which was attributable to thrombectomy treatment of that vessel segment during the same procedure. None of the control patients demonstrated VW enhancement of their intracranial vasculature on T1-weighted images. CONCLUSIONS The study findings suggest that VW injury incurred during stent retriever thrombectomy can be reliably detected utilizing contrast-enhanced 3-T VW-MRI. The results further demonstrate that endothelial injury is associated with oversizing of stent retrievers relative to the treated vessel. Further studies are needed to evaluate the clinical significance of endothelial injury and to characterize the differential effects of various devices.

The circle of Willis predicts the antihypertensive effects of carotid artery stenting

OBJECTIVE Carotid artery stenting (CAS) has antihypertensive effects, but the durability and degree of this response remain variable. The authors propose that this clinical variability is a function of the presence or absence of a complete circle of Willis (COW). Incomplete COWs perfuse through a higher-resistance pial collateral pathway, and therefore patients may require a higher mean arterial pressure (MAP). Carotid artery revascularization in these patients would reduce the end-organ collateral demand that has been hypothesized to drive the MAP response. METHODS Using a retrospective, nonrandomized within-subject case-control design, the authors compared the postoperative effects of CAS in patients with and without a complete COW by using changes in MAP and antihypertensive medication as end points. They recorded MAP and antihypertensive medications 3 months prior to surgery, preoperatively, immediately postoperatively, and at the 3-month follow-up. RESULTS Data were collected from 64 consecutive patients undergoing CAS. Patients without a complete COW (25%) were more likely to demonstrate a decrease in BP response to stenting (i.e., a drop in MAP of 10 mm Hg and/or a reduction or cessation of BP medications at 3 months postoperatively). Of the patients in the incomplete COW cohort, 75% had this outcome, whereas of those in the complete COW cohort, only 41% had it (p < 0.041). These findings remained statistically significant in a logistic regression analysis for possible confounders (p < 0.024). A receiver operating curve analysis of preoperative data indicated that a MAP > 96.3 mm Hg was 55.5% sensitive and 57.4% specific for predicting a complete COW and that patients with a MAP > 96.3 mm Hg were more likely to demonstrate a good MAP decrease following CAS (p < 0.0092). CONCLUSIONS CAS is associated with a significant decrease in MAP and/or a reduction/cessation in BP medications in patients in whom a complete COW is absent.

Abstract 050: Improvements in Door to Groin Puncture Time for Surgical Stroke After Quality Protocol Interventions at the University of California, San Diego

Introduction: Delays in door to groin puncture time (DGPT) for patients with ischemic stroke caused by acute large vessel occlusion (LVO) correlate with worse clinical outcomes. Stroke centers aim to minimize DGPT to facilitate prompt intervention and limit ischemic brain injury. In this study, we present the results of a comprehensive quality assessment at the University of California, San Diego (UCSD). From 2015 to 2016, institutional implementation of a quality improvement protocol significantly reduced DGPT.

Materials and Methods: Beginning July 2015, the UCSD interdisciplinary stroke team implemented a series of quality improvement measures to decrease DGPT, with a target of 90 minutes or less. After each case, areas of inefficiency were identified and changes were implemented based on direct feedback from neurointerventional physicians and ancillary staff. Changes included: 1) creation of a pager group notification system to activate the entire neurointerventional team simultaneously, 2) consistently involving anesthesia with each neurointervention, 3) streamlining communication between the vascular neurology and neurointervention teams, and 4) structuring parallel workflows to enhance mobilization speed. R statistical software was utilized to compare DGPT before and after implementation of these process improvements. Patients were divided into three groups based on the date of their intervention as follows: 23 patients treated from July-December 2015, 24 patients treated from January-July 2016, and 14 patients treated from July 2016-December 2016. A multivariable univariate binary logistic regression model was constructed to capture predictors of compliance with our target DGPT (<90 min). Variables analyzed included: date of intervention, mode of patient admission (i.e. transfer, direct admit from ED, inpatient), hospital location, age, and gender.

Results: 61 patients underwent mechanical thrombectomy for treatment of acute LVO from July 2015 to December 2016. In our analysis, date of intervention—as a proxy for implementation of process improvement protocols—and mode of admission were predictive of compliance with target DGPT. Patients who were treated from July 2016 to December 2016—after full implementation of process improvements— were 9.5 times more likely to meet or exceed the target DGPT compared to patients treated July 2015 to December 2015 (p=0.01). Additionally, arrival via transfer from an outside hospital was determined to be an independent predictor of meeting DGPT goals. (p=0.02).

Conclusion: UCSD’s quality improvement process effected dramatic, statistically significant improvement in DGPT. This analysis demonstrates the utility of a formal quality improvement system at a large, academic comprehensive stroke center.

Low-profile Visualized Intraluminal Support Junior Device for the Treatment of Intracranial Aneurysms

Objective: Early case series suggest that the recently introduced Low-profile Visualized Intraluminal Support Junior (LVIS Jr.) device (MicroVention-Terumo, Inc., Tustin, CA) may be used to treat wide-necked aneurysms that would otherwise require treatment with intrasaccular devices or open surgery. We report our single-center experience utilizing LVIS Jr. to treat intracranial aneurysms involving 1.8-2.5 mm parent arteries.

Methods: We retrospectively reviewed records of patients treated with the LVIS Jr. device for intracranial aneurysms at a single center. A total of 21 aneurysms were treated in 18 patients. Aneurysms were 2-25 mm in diameter; one was ruptured, while three had recurred after previous rupture and treatment. Lesions were distributed across the anterior (n=12) and posterior (n=9) circulations. Three were fusiform morphology.

Results: Stent deployment was successful in 100% of cases with no immediate complications. Seventeen aneurysms were treated with stent-assisted coil embolization resulting in immediate complete occlusion in 94% of cases. Two fusiform aneurysms arising from the posterior circulation were further treated with elective clip ligation after delayed expansion and recurrence; no lesions required further endovascular treatment. Four aneurysms were treated by flow diversion with stand-alone LVIS Jr. stent, and complete occlusion was achieved in three cases. Small foci of delayed ischemic injury were noted in two patients in the setting of antiplatelet medication noncompliance. No in-stent stenosis, migration, hemorrhage, or permanent deficits were observed. Good functional outcome based on the modified Rankin Scale score (mRS ≤ 2) was achieved in 100% of cases.

Conclusion: Our midterm results suggest that the LVIS Jr. stent may be used for a variety of intracranial aneurysms involving small parent arteries (1.8-2.5 mm) with complete angiographic occlusion, parent vessel preservation, and functional clinical outcomes. This off-label expansion would increase the number of aneurysms amenable to endovascular treatment. Future studies may build upon our experiences with flow diversion and treatment of complex or multiple lesions.

Simulator-Based Angiography and Endovascular Neurosurgery Curriculum: A Longitudinal Evaluation of Performance Following Simulator-Based Angiography Training

This study establishes performance metrics for angiography and neuroendovascular surgery procedures based on longitudinal improvement in individual trainees with differing levels of training and experience.

Over the course of 30 days, five trainees performed 10 diagnostic angiograms, coiled 10 carotid terminus aneurysms in the setting of subarachnoid hemorrhage, and performed 10 left middle cerebral artery embolectomies on a Simbionix Angio Mentor™ simulator. All procedures were nonconsecutive. Total procedure time, fluoroscopy time, contrast dose, heart rate, blood pressures, medications administered, packing densities, the number of coils used, and the number of stent-retriever passes were recorded. Image quality was rated, and the absolute value of technically unsafe events was recorded. The trainees’ device selection, macrovascular access, microvascular access, clinical management, and the overall performance of the trainee was rated during each procedure based on a traditional Likert scale score of 1=fail, 2=poor, 3=satisfactory, 4=good, and 5=excellent. These ordinal values correspond with published assessment scales on surgical technique.

After performing five diagnostic angiograms and five embolectomies, all participants demonstrated marked decreases in procedure time, fluoroscopy doses, contrast doses, and adverse technical events; marked improvements in image quality, device selection, access scores, and overall technical performance were additionally observed (p < 0.05). Similarly, trainees demonstrated marked improvement in technical performance and clinical management after five coiling procedures (p < 0.05). However, trainees with less prior experience deploying coils continued to experience intra-procedural ruptures up to the eighth embolization procedure; this observation likely corresponded with less tactile procedural experience to an exertion of greater force than appropriate for coil placement.

Trainees across all levels of training and prior experience demonstrated a significant performance improvement after completion of our simulator curriculum consisting of five diagnostic angiograms, five embolectomy cases, and 10 aneurysm coil embolizations.

Hypoplastic Internal Carotid Artery Co-Presenting with Neurofibromatosis and Intracranial Masses

Neurofibromatosis type 1 (NF1) is associated with systemic vascular disease, and it can also affect intracranial vasculature in a small percentage of patients. Very rarely, NF1 may co-present with hypoplasia of the internal carotid artery (ICA). Prior reports have documented NF1 with bilateral optic gliomas and a unilateral hypoplastic internal carotid artery; however, we report a case with the aforementioned findings in addition to a right-sided lentiform mass. This case report further suggests a common congenital pathway related to neurofibromin loss of function resulting in both nerve sheath tumors and cerebrovascular anomalies.

The Inter-Mammary Sticky Roll: A Novel Technique for Securing a Doppler Ultrasonic Probe to the Precordium for Venous Air Embolism Detection

Venous air embolism is a devastating and potentially life-threatening complication that can occur during neurosurgical procedures. We report the development and use of the “inter-mammary sticky roll,” a technique to reliably secure a precordial Doppler ultrasonic probe to the chest wall during neurosurgical cases that require lateral decubitus positioning. We have found that this noninvasive technique is safe, and effectively facilitates a constant Doppler signal with no additional risk to the patient.

Intracranial Rhabdomyoma: Case Report and Review of the Literature

A 24-year-old male presented with eight months of increasingly severe frontal headaches, decreased right facial sensation, and periodic vertigo. Magnetic resonance imaging demonstrated a heterogeneously contrast-enhancing mass involving and expanding the right foramen ovale.  A biopsy of the lesion was performed, and the final pathologic diagnosis revealed a neoplastic rhabdomyoma. To date, only five cases of intracranial rhabdomyoma have been reported, and a rhabdomyoma involving the trigeminal nerve has never been described in an adult. This manuscript reviews the available literature and highlights the clinical, imaging, pathologic characteristics, and surgical management of these exceedingly rare lesions.