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.

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.

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.

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.