The ClearPoint Array Frame: An MRI Compatible System that Supports Non-craniotomy, Multi-trajectory (NCMT) Stereotactic Procedures.

BACKGROUND: With continued evolution in stereotactic techniques and an expanding armamentarium of surgical therapeutic options, non-craniotomy stereotactic procedures in neuro-oncology are becoming increasingly complex, often requiring multi-trajectory approaches. Here we demonstrate that the ClearPoint SmartFrame Array (Solana Beach, California, USA), a second-generation magnetic resonance imaging-compatible stereotactic frame, supports such non-craniotomy, multi-trajectory (NCMT) stereotactic procedures. METHODS: We previously published case reports demonstrating the feasibility of NCMT through the ClearPoint SmartFrame Array. Here we prospectively followed the next 10 consecutive patients who underwent such multi-trajectory procedures to further establish procedural safety and clinical utility. RESULTS: Ten patients underwent complex, multi-trajectory stereotactic procedures, including combinations of needle biopsy ± cyst drainage and laser interstitial thermal therapy targeting geographically distinct regions of neoplastic lesions under the same anesthetic event. The median maximal radial error of stereotaxis was 1.0 mm. In all cases, definitive diagnosis was achieved, and >90% of the intended targets were ablated. The average stereotaxis time for the multi-trajectory procedure was 119 ± 22.2 minutes, comparing favorably to our previously published results of single-trajectory procedures (80 ± 9.59 minutes, P = 0.125). There were no procedural complications. Post-procedure, the neurologic condition of 1 patient improved, while the remaining 9 patients remained stable. All patients were discharged home, with a median hospital stay of 1 day (range: 1-12 days). With a median follow-up of 376 days (range: 155-1438 days), there were no 30-day readmissions or wound complications. CONCLUSIONS: Geographically distinct regions of brain cancer can be safely and accurately accessed through the ClearPoint Array frame in NCMT stereotactic procedures.

Stereotactic needle biopsy and laser ablation of geographically distinct lesions through a novel magnetic resonance imaging-compatible cranial stereotaxic frame: illustrative case.

BACKGROUND: Current technologies that support stereotactic laser ablation (SLA) of geographically distinct lesions require placement of multiple bolts or time-consuming, intertrajectory adjustments. OBSERVATIONS: Two geographically distinct nodular lesions were safely biopsied and laser ablated in a 62-year-old woman with recurrent glioblastoma using the ClearPoint Array frame, a novel magnetic resonance imaging-compatible stereotactic frame designed to support independent parallel trajectories without intertrajectory frame adjustment. LESSONS: Here, the authors provide a proof-of-principle case report demonstrating that geographically distinct lesions can be safely biopsied and ablated through parallel trajectories supported by the ClearPoint Array frame without intertrajectory adjustment.

Persistent racial and ethnic disparities as a potential source of epilepsy surgery underutilization: Analysis of large national datasets from 2006-2016.

OBJECTIVE: High volume surgical epilepsy centers have reported a decrease in surgical resections and an increase in intracranial monitoring. Despite this increase in complexity, epilepsy surgery remains significantly underutilized. The goal of this study is to examine the utilization of and access to epilepsy surgery in the United States from 2006 to 2016. METHODS: We used administrative datasets from the National Inpatient Sample (NIS) and Center for Medicare and Medicaid Services (CMS) to report national estimates of epilepsy surgery and changes in surgery types. We also examined disparities and barriers in access to epilepsy surgery. RESULTS: Inpatient epilepsy admissions increased from 2.41 to 5.78 per 100,000 between 2006 and 2016, while surgical epilepsy admissions plateaued after 2011. Open resections comprised 75 % of all surgical cases from 2006 to 2011 then decreased each year to 50 % in 2016 with both temporal and extratemporal resections decreasing proportionally. Intracranial monitoring increased in the last two years of the study due to an increase in SEEG/depth electrode cases. The multivariate analysis showed that patients with Medicaid (OR 0.75, 95 % CI 0.67-0.83) and Medicare (OR 0.62, 95 % CI 0.54-0.70) were significantly less likely to undergo epilepsy surgery compared to those with private insurance. Black patients were less likely to undergo epilepsy surgery than White or Hispanic patients (OR 0.57, 95 % CI 0.49-0.67). No significant difference was found in epilepsy surgery rates after implementation of the Affordable Care Act (ACA) in 2014. CONCLUSION: This study identifies recent trends in epilepsy surgical approaches and suggests that improving access to care does not necessarily address disparities present in the treatment of epilepsy patients who need surgical care.

Assessment of the Interrater Reliability of the Congress of Neurological Surgeons Microanastomosis Assessment Scale.

BACKGROUND: The potential for simulation-based learning in neurosurgical training has led the Congress of Neurosurgical Surgeons to develop a series of simulation modules. The Northwestern Objective Microanastomosis Assessment Tool (NOMAT) was created as the corresponding assessment tool for the Congress of Neurosurgical Surgeons Microanastomosis Module. The face and construct validity of the NOMAT have been previously established. OBJECTIVE: To further validate the NOMAT by determining its interrater reliability (IRR) between raters of varying levels of microsurgical expertise. METHODS: The NOMAT was used to assess residents' performance in a microanastomosis simulation module in 2 settings: Northwestern University and the Society of Neurological Surgeons 2014 Boot Camp at the University of Indiana. At Northwestern University, participants were scored by 2 experienced microsurgeons. At the University of Indiana, participants were scored by 2 postdoctoral fellows and an experienced microsurgeon. The IRR of NOMAT was estimated by computing the intraclass correlation coefficient using SPSS v22.0 (IBM, Armonk, New York). RESULTS: A total of 75 residents were assessed. At Northwestern University, 21 residents each performed microanastomosis on 2 model vessels of different sizes, one 3 mm and one 1 mm. At the University of Indiana, 54 residents performed a single microanastomosis procedure on 3-mm vessels. The intraclass correlation coefficient of the total NOMAT scores was 0.88 at Northwestern University and 0.78 at the University of Indiana. CONCLUSION: This study indicates high IRR for the NOMAT. These results suggest that the use of raters with varying levels of expertise does not compromise the precision or validity of the scale. This allows for a wider adoption of the scale and, hence, a greater potential educational impact.

Mastoid Epidermoid Tumor and Associated Dural Arteriovenous Fistula with Venous Sinus Occlusion.

BACKGROUND: Dural arteriovenous fistula (DAVF) is an abnormal vascular connection between arterial and venous channels within dura mater. Although DAVFs have been linked to other types of intracranial tumors, this is the first case reporting the association between DAVF and an epidermoid tumor. CASE DESCRIPTION: A middle-aged patient with chronic headache presented with Borden type II DAVF draining into the right transverse sigmoid junction and was also found to have an epidermoid tumor over the right mastoid. The patient underwent staged embolization of the fistula through both transvenous and transarterial routes. Continuous intraoperative venous pressure monitoring confirmed marked reduction in intracranial venous pressure, and the patient's symptoms completely resolved. However, the fistula still remained. The residual DAVF was then surgically disconnected, and the epidermoid tumor was resected in the same procedure. CONCLUSIONS: This case demonstrates a DAVF can be associated with an epidermoid tumor. Tumor can compromise the venous outflow, which can then lead to intracranial venous hypertension and development of the DAVF. Venous pressure monitoring offers an objective method to verify resolution of venous hypertension, which might correlate with resolution of clinical symptoms.

Value of Targeted Epidural Blood Patch and Management of Subdural Hematoma in Spontaneous Intracranial Hypotension: Case Report and Review of the Literature.

BACKGROUND: Spontaneous intracranial hypotension (SIH) is a more common than previously noted condition (1-2.5 per 50,000 persons) typically caused by cerebrospinal fluid (CSF) leakage. Initial treatment involves conservative therapies, but the mainstay of treatment for patients who fail conservative management is the epidural blood patch (EBP). Subdural hematoma (SDH) is a common complication occurring with SIH, but its management remains controversial. METHODS: In this report, we discuss a 62-year-old woman who presented with a 5-week history of orthostatic headaches associated with nausea, emesis, and neck pain. Despite initial imaging being negative, the patient later developed classic imaging evidence characteristic of SIH. Magnetic resonance imaging was unrevealing for the source of the CSF leak. Radionuclide cisternography showed possible CSF leak at the right-sided C7-T1 nerve root exit site. After failing a blind lumbar EBP, subsequent targeted EBP at C7-T1 improved the patient's symptoms. Two days later she developed a new headache with imaging evidence of worsening SDH with midline shift requiring burr hole drainage. This yielded sustained symptomatic relief and resolution of previously abnormal imaging findings at 2-month follow-up. RESULTS: A literature review revealed 174 cases of SIH complicated by SDH. This revealed conflicting opinions concerning the management of this condition. CONCLUSIONS: Although blind lumbar EBP is often successful, targeted EBP has a lower rate of patients requiring a second EBP or other further treatment. On the other hand, targeted EBP has a larger risk profile. Depending on the clinic situation, treatment of the SDH via surgical evacuation may be necessary.

Use of a harvested radial artery graft with preservation of the vena comitantes to reduce spasm risk and improve graft patency for extracranial to intracranial bypass: Technical note.

BACKGROUND AND SIGNIFICANCE: The vessels of choice for cerebrovascular high-flow direct bypass procedures are the radial artery and the saphenous vein. Radial artery grafts have become favored over saphenous vein grafts because of higher patency rates and better size matching to appropriate recipient vessels. Radial grafts are prone to spasm however, and this may be seen in 4-10% of cases and can be associated with ischemic sequelae. The standard technique for radial artery harvest calls for complete separation of the artery from its adventitial attachments and associated venous network. There is reason to believe that this could contribute to spasm risk and possibly even thrombosis. Radial graft outcomes appear to be improved when the vena comitantes is preserved in cardiac and peripheral applications. We report the novel use of a harvested radial artery graft with preservation of its venae comitantes for extracranial to intracranial bypass. CLINICAL PRESENTATION: The patient is a 59-year-old male who had a blunt head trauma with associated loss of consciousness and who was led to the incidental discovery of a large fusiform middle cerebral artery (MCA) aneurysm. CONCLUSION: Preservation of the vena comitantes when harvesting a radial arterial graft for bypass, along with dual (arterial and venous) anastomoses, and concomitant use of intra-operative vaso-dilatory maneuvers to prevent spasm, may improve overall graft patency and patient outcome.

Increased prevalence and rupture status of feeder vessel aneurysms in posterior fossa arteriovenous malformations.

BACKGROUND: Posterior fossa arteriovenous malformations (AVMs) are considered to have a higher risk of poor outcome, as are AVMs with associated aneurysms. We postulated that posterior fossa malformations may be more prone to associated feeder vessel aneurysms, and to aneurysmal source of hemorrhage. OBJECTIVE: To examine the prevalence and hemorrhagic risk of posterior fossa AVM-associated feeder vessel aneurysms. METHODS: A retrospective review of AVMs was performed with attention paid to location and presence of aneurysms. The hemorrhage status and origin of the hemorrhage was also reviewed. RESULTS: 571 AVMs were analyzed. Of 90 posterior fossa AVMs, 34 (37.8%) had aneurysms (85% feeder vessel, 9% intranidal, 15% with both). Of the 481 supratentorial AVMs, 126 (26.2%) harbored aneurysms (65% feeder vessel, 29% intranidal, 6% both). The overall incidence of feeder aneurysms was higher in posterior fossa AVMs, which were evident in 34.4% of infratentorial AVMs compared to 18.5% of supratentorial malformations (p<0.01). The presence of intranidal aneurysms was similar in both groups (9.2% vs 8.8%). Feeder artery aneurysms were much more likely to be the source of hemorrhage in posterior fossa AVMs than in supratentorial AVMs (30% vs 7.6%, p<0.01). CONCLUSIONS: Posterior fossa AVMs are more prone to developing associated aneurysms, specifically feeder vessel aneurysms. Feeder vessel aneurysms are more likely to be the source of hemorrhage in the posterior fossa. As such, they may be the most appropriate targets for initial and prompt control by embolization or surgery due to their elevated threat.

Comparison of the Efficacy and Safety of Endovascular Coiling Versus Microsurgical Clipping for Unruptured Middle Cerebral Artery Aneurysms: A Systematic Review and Meta-Analysis.

OBJECTIVE: Middle cerebral artery aneurysms (MCAAs) are regularly treated by both microsurgical clipping and endovascular coiling. We performed a systematic meta-analysis to compare the safety and efficacy of these 2 methods. METHODS: Literature was reviewed for all studies reporting angiographic occlusion and/or functional outcomes in adults with unruptured MCAA treated by endovascular coiling or microsurgical clipping. All studies in English that reported results for adults (≥18 years) with unruptured MCAAs, from 1990 to 2011 were considered for inclusion. RESULTS: Twenty-six studies involving 2295 aneurysms treated with clipping or coiling for unruptured MCAAs were included for analysis. There were 1530 aneurysms that were treated with clipping and 765 aneurysms treated with coiling. Pooled analysis revealed failure of aneurysmal occlusion in 3.0% (95% confidence interval [CI] 1.2%-7.4%) of clipped cases. Pooled analysis of 15 studies (606 aneurysms) involving coiling and occlusion revealed lack of occlusion rates of 47.7% (95% CI 43.6%-51.8%) with the fixed-effects model and 48.2% (95% CI 39.0%-57.4%) with the random-effects model. Thirteen studies examined neurological outcomes after clipping and were pooled for analysis. Both fixed-effect and random-effect models revealed unfavorable outcomes in 2.1% (95% CI 1.3%-3.3%) of patients. There were 17 studies evaluating potential unfavorable neurological outcomes after coiling that were pooled for analysis. Fixed-effect and random-effect models revealed unfavorable outcomes in 6.5% (95% CI 4.5%-9.3%) and 4.9% (95% CI 3.0%-8.1%) of patients, respectively. CONCLUSIONS: Based on this systematic review and meta-analysis of unruptured MCAAs, after careful consideration of patient, aneurysmal, and treatment center factors, we recommend surgical clipping for unruptured MCAA.

Novel use of a double lumen balloon catheter for venous sinus thrombolysis and venoplasty.

We describe the novel use of a double lumen balloon catheter for venous sinus thrombolysis and venoplasty. Cerebral venous sinus thrombosis is a rare disease that is usually treated with medical anticoagulation. In certain refractory cases, surgical or endovascular thrombolysis and thrombectomy may be required. A 48 year-old man on anticoagulation for cerebral venous sinus thrombosis presented with nausea, vomiting and worsening hemiparesis. The patient underwent endovascular venous sinus thrombolysis and venoplasty with continuous in situ tissue plasminogen activator (tPA) infusion over 48 hours. This novel approach to the endovascular treatment of venous sinus thrombosis, including the use of a double lumen balloon was advantageous, as it allowed direct infusion of tPA through the balloon catheter without having to exchange the balloon for a microcatheter.

Microsurgical Treatment of Previously Coiled Intracranial Aneurysms: Systematic Review of the Literature.

OBJECTIVE: To assess indications, complications, clinical outcomes, and technical nuances of microsurgical treatment of previously coiled intracranial aneurysms. METHODS: A systematic review of the literature was performed using PubMed/MEDLINE and EMBASE databases from January 1990 to December 2013. English-language articles reporting on microsurgical treatment of previously coiled intracranial aneurysms were included. Articles that involved embolization materials other than coils were excluded. Data on aneurysm characteristics, indications for surgery, techniques, complications, angiographic obliteration rates, and clinical outcomes were collected. RESULTS: The literature review identified 29 articles reporting on microsurgical clipping of 375 previously coiled aneurysms. Of the aneurysms, 68% were small (<10 mm). Indications for clipping included the presence of a neck remnant (48%) and new aneurysmal growth (45%). Rebleeding before clipping was reported in 6% of cases. Coil extraction was performed in 13% of cases. The median time from initial coiling to clipping was 7 months. The angiographic cure rate was 93%, with morbidity and mortality of 9.8% and 3.6%, respectively. CONCLUSIONS: Microsurgical clipping of previously coiled aneurysms can result in high obliteration rates with relatively low morbidity and mortality in select cases. Considerations for microsurgical strategies include the presence of sufficient aneurysmal tissue for clip placement and the potential need for temporary occlusion or flow arrest. Coil extraction is not needed in most cases.

Technology and simulation to improve patient safety.

Improving the quality and efficiency of surgical techniques, reducing technical errors in the operating suite, and ultimately improving patient safety and outcomes through education are common goals in all surgical specialties. Current surgical simulation programs represent an effort to enhance and optimize the training experience, to overcome the training limitations of a mandated 80-hour work week, and have the overall goal of providing a well-balanced resident education in a society with a decreasing level of tolerance for medical errors.

The cognitive and technical skills impact of the Congress of Neurological Surgeons simulation curriculum on neurosurgical trainees at the 2013 Neurological Society of India meeting.

OBJECTIVE: To assess the impact of a simulation-based educational curriculum of 4 modules on neurosurgical trainees at the Neurological Societies of India annual meeting, which was held in Mumbai, India, in December 2013. METHODS: We developed a microanastomosis, anterior cervical discectomy and fusion (ACDF), posterior cervical fusion (PCF), and durotomy repair and their corresponding objective assessment scales. Each module was divided into 3 components: 1) a before didactic cognitive knowledge and technical skills testing, 2) a didactic lecture, and 3) an after didactic cognitive knowledge and technical skills testing. We compared the trainees' cognitive and technical scores from the before and after testing phases. Wilcoxon sum rank test was used to test statistical significance. The incorporation of a simulation-based educational program into neurosurgical education curriculum has faced a number of barriers. It is essential to develop and assess the success and feasibility of simulation-based modules on neurosurgical residents. RESULTS: The knowledge test median scores increased from 60%, 69% to 72%, and 60% to 80%, 85%, 90%, and 75% on the microanastomosis, ACDF, PCF, and durotomy modules, respectively (P < 0.05). The practical hands-on scores increased from 45%, 45% to 60%, and 65% to 62%, 68%, 81%, and 70% on the microanastomosis, ACDF, PCF, and durotomy modules, respectively (P < 0.05). CONCLUSIONS: Our course suggests that a simulation-based neurosurgery curriculum has the potential to enhance resident knowledge and technical proficiency.