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.

Reducing frame rate and pulse rate for routine diagnostic cerebral angiography: ALARA principles in practice

OBJECTIVE

Diagnostic cerebral angiograms (DCAs) are widely used in neurosurgery due to their high sensitivity and specificity to diagnose and characterize pathology using ionizing radiation. Eliminating unnecessary radiation is critical to reduce risk to patients, providers, and health care staff. We investigated if reducing pulse and frame rates during routine DCAs would decrease radiation burden without compromising image quality.

METHODS

We performed a retrospective review of prospectively acquired data after implementing a quality improvement protocol in which pulse rate and frame rate were reduced from 15 p/s to 7.5 p/s and 7.5 f/s to 4.0 f/s respectively. Radiation doses and exposures were calculated. Two endovascular neurosurgeons reviewed randomly selected angiograms of both doses and blindly assessed their quality.

RESULTS

A total of 40 consecutive angiograms were retrospectively analyzed, 20 prior to the protocol change and 20 after. After the intervention, radiation dose, radiation per run, total exposure, and exposure per run were all significantly decreased even after adjustment for BMI (all p<0.05). On multivariable analysis, we identified a 46% decrease in total radiation dose and 39% decrease in exposure without compromising image quality or procedure time.

CONCLUSIONS

We demonstrated that for routine DCAs, pulse rate of 7.5 with a frame rate of 4.0 is sufficient to obtain diagnostic information without compromising image quality or elongating procedure time. In the interest of patient, provider, and health care staff safety, we strongly encourage all interventionalists to be cognizant of radiation usage to avoid unnecessary radiation exposure and consequential health risks.

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.

Direct Transorbital Approach for Treatment of Carotid Cavernous Fistula: An Illustrative Case Series

BACKGROUND AND OBJECTIVES

Endovascular techniques have become the first-line treatment for carotid-cavernous fistulas (CCFs). Direct transorbital venous access may be used if anatomic constraints limit standard transarterial or transvenous access. We describe our institutional experience with the transorbital approach for Barrow Type A-D CCFs.

METHODS

Patients with CCFs undergoing transorbital endovascular treatment at our institution between 2017 and 2019 were retrospectively reviewed. Demographic, treatment, and outcome data were collected.

RESULTS

Eight patients met inclusion criteria, 4 female and 4 male patients. The mean age was 43 years, with 6 right-sided CCF and 2 left-sided CCFs. Symptoms were present for an average of 1.5 months before treatment. All patients presented with eye pain and subjective visual changes. Seven (87.5%) patients presented with proptosis, 6 (75%) patients had elevated intraocular pressure (IOP), and 3 (37.5%) patients had ophthalmoplegia. Six CCFs (75%) were spontaneous, and 2 CCFs (25%) were traumatic. Barrow types were A (n = 1), B (n = 1), C (n = 1), and D (n = 5). All patients underwent direct percutaneous transorbital embolization with coils followed by Onyx. Three patients had undergone prior transarterial and/or transvenous treatment. A radiographic cure was obtained in all patients after direct transorbital embolization. After CCF cure, cranial nerve palsies resolved in 66.7% of patients, visual acuity in the affected eye was improved or stable in 75% of patients, and IOP had normalized in 85.7% of patients. Proptosis improved in all patients, with complete resolution in 75%.

CONCLUSION

Direct transorbital embolization is a safe and potentially curative treatment for all 4 Barrow types of CCFs.

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.

Novel association of blunt cerebrovascular injuries with the San Diego-Mexico border wall height extension

BACKGROUND

The San Diego-Mexico border wall height extension is associated with increased traumatic injuries and related costs after wall falls. We report previous trends and a neurological injury type not previously associated with border falls: blunt cerebrovascular injuries (BCVIs).

METHODS

In this retrospective cohort study, patients who presented to the UC San Diego Health Trauma Center for injuries from border wall falls from 2016-2021 were considered. Patients were included if they were admitted in the pre-height extension period (January 2016-May 2018) or post-height extension period (June 2018-December 2021). Demographics, clinical data, and hospital stay data were compared.

RESULTS

We identified 383 patients, 51 (68.6% male; mean age 33.5 years) in the pre-height extension cohort and 332 (77.1% male; mean age 31.5 years) in the post-height extension cohort. There were 0 and 5 BCVIs in the pre-height and post-height extension groups respectively. BCVIs were associated with increased injury severity scores (9.16 vs 31.33; p<0.001), median ICU length of stay (0 [IQR 0-3] vs 5 [IQR 2-21]; p=0.022), and total hospital charges ($163,490 [IQR $86,578, $282,036] vs $835,260 [IQR $171,049, $1,933,996]; p=0.048). Poisson modeling found BCVI admissions were 0.21 (95%CI 0.07-0.41; p=0.042) per month higher post-height extension.

CONCLUSIONS

We review the injuries correlated with the border wall extension and reveal an association with rare, potentially devastating BCVIs that were not seen before the border wall modifications. These BCVIs and associated morbidity shed light on the trauma increasingly found at the southern US border, which may be informative for future infrastructure policy decisions.

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.

Physiological Responses and Training Satisfaction During National Rollout of a Neurosurgical Intraoperative Catastrophe Simulator for Resident Training

BACKGROUND

Systematic use of neurosurgical training simulators across institutions is significantly hindered by logistical and financial constraints.

OBJECTIVE

To evaluate feasibility of large-scale implementation of an intraoperative catastrophe simulation, we introduced a highly portable and low-cost immersive neurosurgical simulator into a nationwide curriculum for neurosurgery residents, during years 2016 to 2019.

METHODS

The simulator was deployed at 9 Society of Neurological Surgeons junior resident courses and a Congress of Neurological Surgeons education course for a cohort of 526 residents. Heart rate was tracked to monitor physiological responses to simulated stress. Experiential survey data were collected to evaluate simulator fidelity and resident attitudes toward simulation.

RESULTS

Residents rated the simulator positively with a statistically significant increase in satisfaction over time accompanying refinements in the simulator model and clinical scenario. The simulated complications induced stress-related tachycardia in most participants (n = 249); however, a cohort of participants was identified that experienced significant bradycardia (n = 24) in response to simulated stress.

CONCLUSION

Incorporation of immersive neurosurgical simulation into the US national curriculum is logistically feasible and cost-effective for neurosurgical learners. Participant surveys and physiological data suggest that the simulation model recreates the situational physiological stress experienced during practice in the live clinical environment. Simulation may provide an opportunity to identify trainees with maladaptive responses to operative stress who could benefit from additional simulated exposure to mitigate stress impacts on performance.

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.

Shunt freedom in slit ventricle syndrome: using paradoxical ventriculomegaly following lumbar shunting to our advantage. Illustrative cases

BACKGROUND

The authors present two cases of paradoxical ventriculomegaly after lumboperitoneal (LP) shunting in patients with slit ventricle syndrome (SVS).

OBSERVATIONS

After placement of an LP shunt, both patients rapidly developed radiographic and clinically symptomatic ventricular enlargement. The then generous ventricular corridors allowed both patients to be treated by endoscopic third ventriculostomy (ETV) with concurrent removal of their LP shunt. The patients then underwent staged increases in their shunt resistance to the maximum setting and remain asymptomatic.

LESSONS

The authors suggest that this paradoxical ventriculomegaly may have resulted from a pressure gradient between the shunt systems in the intra- and extraventricular spaces due to a noncommunicating etiology of their hydrocephalus. ETV may successfully exploit this newfound obstructive hydrocephalus and provide resolution of the radiographic and clinical hydrocephalus through allowing for improved communication between the cranial and lumbar cerebrospinal fluid spaces in SVS.

Robotics and Artificial Intelligence in Endovascular Neurosurgery

The use of artificial intelligence (AI) and robotics in endovascular neurosurgery promises to transform neurovascular care. We present a review of the recently published neurosurgical literature on artificial intelligence and robotics in endovascular neurosurgery to provide insights into the current advances and applications of this technology.

The PubMed database was searched for "neurosurgery" OR "endovascular" OR "interventional" AND "robotics" OR "artificial intelligence" between January 2016 and August 2021. A total of 1296 articles were identified, and after applying the inclusion and exclusion criteria, 38 manuscripts were selected for review and analysis. These manuscripts were divided into four categories: 1) robotics and AI for the diagnosis of cerebrovascular pathology, 2) robotics and AI for the treatment of cerebrovascular pathology, 3) robotics and AI for training in neuroendovascular procedures, and 4) robotics and AI for clinical outcome optimization.

The 38 articles presented include 23 articles on AI-based diagnosis of cerebrovascular disease, 10 articles on AI-based treatment of cerebrovascular disease, two articles on AI-based training techniques for neuroendovascular procedures, and three articles reporting AI prediction models of clinical outcomes in vascular disorders of the brain. Innovation with robotics and AI focus on diagnostic efficiency, optimizing treatment and interventional procedures, improving physician procedural performance, and predicting clinical outcomes with the use of artificial intelligence and robotics. Experimental studies with robotic systems have demonstrated safety and efficacy in treating cerebrovascular disorders, and novel microcatheterization techniques may permit access to deeper brain regions. Other studies show that pre-procedural simulations increase overall physician performance. Artificial intelligence also shows superiority over existing statistical tools in predicting clinical outcomes.

The recent advances and current usage of robotics and AI in the endovascular neurosurgery field suggest that the collaboration between physicians and machines has a bright future for the improvement of patient care. The aim of this work is to equip the medical readership, in particular the neurosurgical specialty, with tools to better understand and apply findings from research on artificial intelligence and robotics in endovascular neurosurgery.

First-in-Human Clinical Experience Using High-Definition Exoscope with Intraoperative Indocyanine Green for Clip Reconstruction of Unruptured Large Pediatric Aneurysm

The operative exoscope is a novel tool that combines the benefits of surgical microscopes and endoscopes to yield excellent magnification and illumination while maintaining a comparatively small footprint and superior ergonomic features. Until recently, current exoscopes have been limited by 2-dimensional viewing; however, recently a 3-dimensional (3D), high-definition (4K-HD) exoscope has been developed (Sony-Olympus, Tokyo, Japan).¹ Our group had previously described the first in-human experiences with this novel tool including microsurgical clipping of intracranial aneurysms. We have highlighted the benefits of the exoscope, which include providing an immersive experience for surgeons and trainees, as well as superior ergonomics as compared with traditional microsurgery.² To date, exoscopic 3D high-definition indocyanine green (ICG) video angiography (ICG-VA) has not been described. ICG-VA, now a mainstay of vascular microsurgery, uses intravenously injected dye to visualize intravascular fluorescence in real time to assess the patency of arteries and assess clip occlusion of aneurysms.^3,4 The ability to safely couple this tool with the novel exoscope has the potential to advance cerebrovascular microsurgery. Here, we present a case of a 11-year-old male with Alagille syndrome, pancytopenia, and peripheral pulmonary stenosis found to have a 12 × 13 × 7 mm distal left M1 aneurysm arising from the inferior M1/M2 junction. The patient was neurologically intact without evidence of rupture. In order to prevent catastrophic rupture, the decision was made to treat the lesion. Due to the patients underlying medical conditions including baseline coagulopathy, surgical management was felt to be superior to an endovascular reconstruction, which would require long-term antiplatelet therapy. Thus the patient underwent a left-sided pterional craniotomy with exoscopic 3D ICG-VA. As demonstrated in Video 1, ICG-VA was performed before definitive clip placement in order to understand flow dynamics with particular emphasis on understanding the middle cerebral artery outflow. Postoperatively, the patient remained at his neurologic baseline and subsequent imaging demonstrated complete obliteration of the aneurysm without any neck remnant. The patient continues to follow and remains asymptomatic and neurologically intact without radiographic evidence of residual or recurrence.

Rotation flap distraction osteogenesis for unicoronal synostosis

Unicoronal craniosynostosis is notoriously difficult to treat, with long-term studies demonstrating high rates of relapse and the need for reoperation using open fronto-orbital advancement. Applying the principles of distraction osteogenesis to cranial vault remodeling has demonstrated promising short-term results that compare favorably with traditional methods, with simultaneous correction of both frontofacial and endocranial morphology, along with significant increases in intracranial volume. Here, the authors demonstrate their technique for rotation flap distraction osteogenesis in the treatment of unicoronal synostosis and provide case examples.

The video can be found here: https://vimeo.com/519505008.

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.

Evidence-Based Recommendations for Seizure Prophylaxis in Patients with Brain Metastases Undergoing Stereotactic Radiosurgery

Symptomatic epilepsy is frequently encountered in patients with brain metastases (BM), affecting up to 25% of them. However, it generally remains unknown whether the risk of seizures in such cases is affected by stereotactic radiosurgery (SRS), which involves highly conformal delivery of high-dose irradiation to the tumor with a minimal effect on adjacent brain tissue. Thus, the role of prophylactic administration of antiepileptic drugs (AED) after SRS remains controversial. A comprehensive review and analysis of the available literature reveals that according to prospective studies, the incidence of seizures after SRS for BM varies from 8% to 22%, and there is no evidence that SRS increases the incidence of symptomatic epilepsy. Therefore, routine prophylactic administration of AED prior to, during, or after SRS in the absence of a seizure history is not recommended. Nevertheless, short-course administration of an AED may be judiciously considered (on the basis of class III evidence) for selected high-risk individuals.

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.

Management of Giant Sacral Pseudomeningocele in Revision Spine Surgery

BACKGROUND

Giant pseudomeningoceles are an uncommon complication of spine surgery. Surgical management and extirpation can be difficult, and guidelines remain unclear.

METHODS

Here, we present a 56-year-old female patient with a history of grade III L5-S1 spondylolisthesis who was treated with 2 prior spine surgeries. The patient was treated with bone grafting for pseudarthrosis and instrumentation from L4 to ilium. After unsuccessful intraoperative and postoperative cerebrospinal fluid drainage and dural repair, the patient presented to the emergency room with debilitating positional headaches.

RESULTS

The patient underwent dural repair with bovine pericardial patch inlay sutured with 7-0 prolene, blood patch, and a dural sealant. Plastic surgery performed a layered closure, using acellular dermal matrix over the dural closure. The bilateral paraspinal flaps were advanced medially to cover the entirety of the acellular dermal matrix, and the fasciocutaneous flaps were then advanced to the midline for a watertight closure. At 3-month follow-up, the patient was headache free and had returned to her activities of daily living.

CONCLUSIONS

We conclude that early consultation with plastic surgery can be greatly beneficial to effectively extirpate dead space and resolve giant sacral pseudomeningoceles, especially if there is concern of persistent cerebrospinal fluid leakage due to relatively immobile avascular soft tissue as a result of prior revision surgery.

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.

Efficacy of riluzole in the treatment of spinal cord injury: a systematic review of the literature

OBJECTIVERiluzole is a glutamatergic modulator that has recently shown potential for neuroprotection after spinal cord injury (SCI). While the effects of riluzole are extensively documented in animal models of SCI, there remains heterogeneity in findings. Moreover, there is a paucity of data on the pharmacology of riluzole and its effects in humans. For the present study, the authors systematically reviewed the literature to provide a comprehensive understanding of the effects of riluzole in SCI.METHODSThe PubMed database was queried from 1996 to September 2018 to identify animal studies and clinical trials involving riluzole administration for SCI. Once articles were identified, they were processed for year of publication, study design, subject type, injury model, number of subjects in experimental and control groups, dose, timing/route of administration, and outcomes.RESULTSA total of 37 studies were included in this study. Three placebo-controlled clinical trials were included with a total of 73 patients with a mean age of 39.1 years (range 18-70 years). For the clinical trials included within this study, the American Spinal Injury Association Impairment Scale distributions for SCI were 42.6% grade A, 25% grade B, 26.6% grade C, and 6.2% grade D. Key findings from studies in humans included decreased nociception, improved motor function, and attenuated spastic reflexes. Twenty-six animal studies (24 in vivo, 1 in vitro, and 1 including both in vivo and in vitro) were included. A total of 520 animals/in vitro specimens were exposed to riluzole and 515 animals/in vitro specimens underwent other treatment for comparison. The average dose of riluzole for intraperitoneal, in vivo studies was 6.5 mg/kg (range 1-10 mg/kg). Key findings from animal studies included behavioral improvement, histopathological tissue sparing, and modified electrophysiology after SCI. Eight studies examined the pharmacology of riluzole in SCI. Key findings from pharmacological studies included riluzole dose-dependent effects on glutamate uptake and its modified bioavailability after SCI in both animal and clinical models.CONCLUSIONSSCI has many negative sequelae requiring neuroprotective intervention. While still relatively new in its applications for SCI, both animal and human studies demonstrate riluzole to be a promising pharmacological intervention to attenuate the devastating effects of this condition.

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.

Decompression Surgery versus Interspinous Devices for Lumbar Spinal Stenosis: A Systematic Review of the Literature

In this retrospective review study, the authors systematically reviewed the literature to elucidate the efficacy and complications associated with decompression and interspinous devices (ISDs) used in surgeries for lumbar spinal stenosis (LSS). LSS is a debilitating condition that affects the lumbar spinal cord and spinal nerve roots. However, a comprehensive report on the relative efficacy and complication rate of ISDs as they compare to traditional decompression procedures is currently lacking. The PubMed database was queried to identify clinical studies that exclusively investigated decompression, those that exclusively investigated ISDs, and those that compared decompression with ISDs. Only prospective cohort studies, case series, and randomized controlled trials that evaluated outcomes using the Visual Analog Scale (VAS), Oswestry Disability Index, or Japanese Orthopedic Association scores were included. A random-effects model was established to assess the difference between preoperative and the 1–2-year postoperative VAS scores between ISD surgery and lumbar decompression. This study included 40 papers that matched our criteria. Twenty-five decompression-exclusive clinical trials with 3,386 patients and a mean age of 68.7 years (range, 31–88 years) reported a 2.2% incidence rate of dural tears and a 2.6% incidence rate of postoperative infections. Eight ISD-exclusive clinical trials with 1,496 patients and a mean age of 65.1 (range, 19–89 years) reported a 5.3% incidence rate of postoperative leg pain and a 3.7% incidence rate of spinous process fractures. Seven studies that compared ISDs and decompression in 624 patients found a reoperation rate of 8.3% in ISD patients vs. 3.9% in decompression patients; they also reported dural tears in 0.32% of ISD patients vs. 5.2% in decompression patients. A meta-analysis of the randomized controlled trials found that the differences in preoperative and postoperative VAS scores between the two groups were not significant. Both decompression and ISD interventions are unique surgical interventions with different therapeutic efficacies and complications. The collected studies do not consistently demonstrate superiority of either procedure over the other but understanding the differences between the two techniques can help tailor treatment regimens for patients with LSS.

Trends in Spine Surgery Training During Neurological and Orthopaedic Surgery Residency: A 10-Year Analysis of ACGME Case Log Data

BACKGROUND

Spine surgery training in the United States currently involves residency training in neurological or orthopaedic surgery. Because of different core residency surgical requirements, the volume of spine surgery procedures may vary between the 2 residencies.

METHODS

We reviewed the Accreditation Council for Graduate Medical Education resident case logs for both orthopaedic surgery and neurological surgery for exposure to spine surgery procedures for the graduating years of 2009 to 2018.

RESULTS

The average number of spine surgery procedures performed during that 10-year period was 433.8 for neurosurgery residents and 119.5 for orthopaedic surgery residents (p < 0.01). From 2009 to 2018, neurosurgery residents saw an increase of 26.5% in spine surgery procedures (from 389.6 to 492.9 procedures), whereas orthopaedic surgery residents saw a decrease of 41.3% (from 141.1 to 82.8 procedures). The 10-year average percentage of total spine procedures among all total surgical cases was 33.5% for neurosurgery residents compared with 6.2% for orthopaedic surgery residents (p < 0.01). This percentage decreased for both neurosurgery residents (35.8% in 2009 to 31.3% in 2018) and orthopaedic surgery residents (7.2% in 2009 to 4.9% in 2018). Neurosurgical residents performed 3.6 times more total spine procedures than orthopaedic surgery residents on average, a number that increased from 2.8-fold in 2009 to 6.0-fold in 2018.

CONCLUSIONS

The case volume of spine surgery procedures varies greatly, with higher rates for neurological surgery and lower rates for orthopaedic surgery residencies, with an increasing discrepancy over time. Although case volume alone cannot solely determine quality of training, it is one measure to assess opportunities to develop optimal spine education around a certain accepted volume of surgical patient care. Not accounted for here are additional postgraduate spine cases performed by orthopaedic surgery residents who pursue spine fellowship training (an additional 300 to 500 cases). The results described herein may help to explore the various needs of and differences between residents seeking to pursue careers in spine as well as the role of spine surgery fellowships currently and in the future.

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.

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.

Abstract TP286: Efficacy of Quality Improvement Protocols Across Diverse Modes of Arrival for Thrombectomy Patients With Ischemic Stroke

Background: Quality improvement protocols (QI) aim to reduce in-hospital delays that result in prolonged door-to-groin-puncture time (DGPT) for the endovascular treatment of ischemic stroke. At our institution, we implemented a comprehensive QI protocol to reduce DGPT from June 2015 to December 2016. Here we discuss the QI protocol on DGPT across diverse modes of arrival to our interventional suite.

Methods: 61 patients underwent mechanical thrombectomy for ischemic stroke during our QI period. Independent samples t-tests were used to investigate differences in DGPT early in the QI protocol (July 2015 to February 2016, n=30) versus late in the QI protocol (March 2016 to December 2016, n=31) for patients that presented via emergency medical services (EMS), inpatient, and hospital transfers.

Results: Each mode of arrival demonstrated reductions in DGPT (Figure 1). The greatest reduction in DGPT was for the 23 patients within the emergency medical services (EMS) group with a mean reduction of 39 minutes which approached, but didn’t achieve, statistical significance (138 vs. 99; p=0.06).

Discussion: QI interventions impact DGPT across different patient arrival methods. QI protocols accounting for patient presentation allow tailored approaches to institutional measures to reduce DGPT.

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.

Prophylactic anticonvulsants in patients with primary glioblastoma

Glioblastoma is the most common form of primary brain cancer in adults and one of the deadliest of human cancers. Seizures are one of the most frequent presentations of glioblastoma. The use of anti-epileptic drugs (AEDs) in glioblastoma patients suffering from seizures is well accepted. However, the role of long-term AED use in patients with glioblastoma without a history of seizures is controversial. Here, we performed a review of the literature to identify studies that examined the use of AEDs in seizure-free glioblastoma patients. We identified one randomized controlled study suggesting no clinical benefit of seizure prophylaxis in this population. Three of the four retrospective studies identified in our search recapitulated this finding, while the remaining study suggested a benefit for prophylactic AED use. All identified studies were focused on seizure incidence in the post-operative period, ranging from 1 week to long-term follow up. Implications of these findings are reviewed herein.

Vertebroplasty for vertebral compression fractures: Placebo or effective?

Vertebral compression fractures (VCFs) are a major cause of pain and disability. Here, we reviewed six randomized control trials (RCTs) focusing on the efficacy vs. placebo effect of vertebroplasty (VP) for symptomatic VCF. Four RCTs involved a nonsurgically treated control group. Two RCTs compared the use of VP vs. a sham surgery control group. Notably, RCTs comparing nonsurgically treated patients as a control group vs. those undergoing VP uniformly reported that VP contributed to improved pain relief. In contrast, RCTs comparing sham surgery vs. VP uniformly reported no significant differences between the two groups.

Clarification of Eponymous Anatomical Terminology: Structures Named After Dr Geoffrey V. Osborne That Compress the Ulnar Nerve at the Elbow

BACKGROUND

In 1957, Dr Geoffrey Osborne described a structure between the medial epicondyle and the olecranon that placed excessive pressure on the ulnar nerve. Three terms associated with such structures have emerged: Osborne's band, Osborne's ligament, and Osborne's fascia. As anatomical language moves away from eponymous terminology for descriptive, consistent nomenclature, we find discrepancies in the use of anatomic terms. This review clarifies the definitions of the above 3 terms.

METHODS

We conducted an extensive electronic search via PubMed and Google Scholar to identify key anatomical and surgical texts that describe ulnar nerve compression at the elbow. We searched the following terms separately and in combination: "Osborne's band," "Osborne's ligament," and "Osborne's fascia." A total of 36 papers were included from 1957 to 2016.

RESULTS

Osborne's band, Osborne's ligament, and Osborne's fascia were found to inconsistently describe the etiology of ulnar neuritis, referring either to the connective tissue between the 2 heads of the flexor carpi ulnaris muscle as described by Dr Osborne or to the anatomically distinct fibrous tissue between the olecranon process of the ulna and the medial epicondyle of the humerus.

CONCLUSIONS

The use of eponymous terms to describe ulnar pathology of the elbow remains common, and although these terms allude to the rich history of surgical anatomy, these nonspecific descriptions lead to inconsistencies. As Osborne's band, Osborne's ligament, and Osborne's fascia are not used consistently across the literature, this research demonstrates the need for improved terminology to provide reliable interpretation of these terms among surgeons.

Analyzing cost-effectiveness of ulnar and median nerve transfers to regain forearm flexion

OBJECTIVE Peripheral nerve transfers to regain elbow flexion via the ulnar nerve (Oberlin nerve transfer) and median nerves are surgical options that benefit patients. Prior studies have assessed the comparative effectiveness of ulnar and median nerve transfers for upper trunk brachial plexus injury, yet no study has examined the cost-effectiveness of this surgery to improve quality-adjusted life years (QALYs). The authors present a cost-effectiveness model of the Oberlin nerve transfer and median nerve transfer to restore elbow flexion in the adult population with upper brachial plexus injury. METHODS Using a Markov model, the authors simulated ulnar and median nerve transfers and conservative measures in terms of neurological recovery and improvements in quality of life (QOL) for patients with upper brachial plexus injury. Transition probabilities were collected from previous studies that assessed the surgical efficacy of ulnar and median nerve transfers, complication rates associated with comparable surgical interventions, and the natural history of conservative measures. Incremental cost-effectiveness ratios (ICERs), defined as cost in dollars per QALY, were calculated. Incremental cost-effectiveness ratios less than $50,000/QALY were considered cost-effective. One-way and 2-way sensitivity analyses were used to assess parameter uncertainty. Probabilistic sampling was used to assess ranges of outcomes across 100,000 trials. RESULTS The authors' base-case model demonstrated that ulnar and median nerve transfers, with an estimated cost of $5066.19, improved effectiveness by 0.79 QALY over a lifetime compared with conservative management. Without modeling the indirect cost due to loss of income over lifetime associated with elbow function loss, surgical treatment had an ICER of $6453.41/QALY gained. Factoring in the loss of income as indirect cost, surgical treatment had an ICER of -$96,755.42/QALY gained, demonstrating an overall lifetime cost savings due to increased probability of returning to work. One-way sensitivity analysis demonstrated that the model was most sensitive to assumptions about cost of surgery, probability of good surgical outcome, and spontaneous recovery of neurological function with conservative treatment. Two-way sensitivity analysis demonstrated that surgical intervention was cost-effective with an ICER of $18,828.06/QALY even with the authors' most conservative parameters with surgical costs at $50,000 and probability of success of 50% when considering the potential income recovered through returning to work. Probabilistic sampling demonstrated that surgical intervention was cost-effective in 76% of cases at a willingness-to-pay threshold of $50,000/QALY gained. CONCLUSIONS The authors' model demonstrates that ulnar and median nerve transfers for upper brachial plexus injury improves QALY in a cost-effective manner.

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.