Direct Versus Indirect Revascularization for Moyamoya: a Large Multicenter Study

BACKGROUND

Moyamoya is a chronic occlusive cerebrovascular disease of unknown etiology causing neovascularization of the lenticulostriate collaterals at the base of the brain. Although revascularization surgery is the most effective treatment for moyamoya, there is still no consensus on the best surgical treatment modality as different studies provide different outcomes.

OBJECTIVE

In this large case series, we compare the outcomes of direct (DR) and indirect revascularisation (IR) and compare our results to the literature in order to reflect on the best revascularization modality for moyamoya.

METHODS

We conducted a multicenter retrospective study in accordance with the Strengthening the Reporting of Observational studies in Epidemiology guidelines of moyamoya affected hemispheres treated with DR and IR surgeries across 13 academic institutions predominantly in North America. All patients who underwent surgical revascularization of their moyamoya-affected hemispheres were included in the study. The primary outcome of the study was the rate of symptomatic strokes.

RESULTS

The rates of symptomatic strokes across 515 disease-affected hemispheres were comparable between the two cohorts (11.6% in the DR cohort vs 9.6% in the IR cohort, OR 1.238 (95% CI 0.651 to 2.354), p=0.514). The rate of total perioperative strokes was slightly higher in the DR cohort (6.1% for DR vs 2.0% for IR, OR 3.129 (95% CI 0.991 to 9.875), p=0.052). The rate of total follow-up strokes was slightly higher in the IR cohort (8.1% vs 6.6%, OR 0.799 (95% CI 0.374 to 1.709) p=0.563).

CONCLUSION

Since both modalities showed comparable rates of overall total strokes, both modalities of revascularization can be performed depending on the patient's risk assessment.

Patient and procedure selection for mechanical thrombectomy: Toward personalized medicine and the role of artificial intelligence

Mechanical thrombectomy (MT) for ischemic stroke due to large vessel occlusion is standard of care. Evidence-based guidelines on eligibility for MT have been outlined and evidence to extend the treatment benefit to more patients, particularly those at the extreme ends of a stroke clinical severity spectrum, is currently awaited. As patient selection continues to be explored, there is growing focus on procedure selection including the tools and techniques of thrombectomy and associated outcomes. Artificial intelligence (AI) has been instrumental in the area of patient selection for MT with a role in diagnosis and delivery of acute stroke care. Machine learning algorithms have been developed to detect cerebral ischemia and early infarct core, presence of large vessel occlusion, and perfusion deficit in acute ischemic stroke. Several available deep learning AI applications provide ready visualization and interpretation of cervical and cerebral arteries. Further enhancement of AI techniques to potentially include automated vessel probe tools in suspected large vessel occlusions is proposed. Value of AI may be extended to assist in procedure selection including both the tools and technique of thrombectomy. Delivering personalized medicine is the wave of the future and tailoring the MT treatment to a stroke patient is in line with this trend.

A review of mechanical thrombectomy techniques for acute ischemic stroke

Mechanical thrombectomy is established as standard of care in the management of acute ischemic stroke due to large vessel occlusion and evidence-based guidelines for mechanical thrombectomy have been defined. As research continues to further expand the eligibility criteria for thrombectomy and the number of thrombectomy procedures increase worldwide, there is also growing focus on innovation of thrombectomy devices, procedural techniques, and related outcomes. Thrombectomy primarily involves use of stent retrievers and distal aspiration techniques, but variations and different combinations of techniques have been reported. As this is a rapidly evolving area in stroke management, there is debate as to which, if any, of these techniques leads to improved clinical outcomes over another and there is a lack of data comparing them. In this review, currently published and distinct techniques of mechanical thrombectomy are described methodically along with illustrations to aid in understanding the subtle differences between the techniques. The perceived benefits of each variation are discussed.

The Accuracy of the TRICKS MRI in Diagnosing and Localizing a Spinal Dural Arteriovenous Fistula: A Feasibility Study

OBJECTIVE

Spinal vascular malformations (SVMs) are a heterogenous group of vascular abnormalities. The gold standard for diagnosis of SVMs is spinal digital subtraction angiography (DSA), which can be challenging because of the large number of segmental arteries that need to be catheterized and the limitations in term of contrast volume used and fluoroscopy time. We describe and compare the use of the time-resolved imaging of contrast kinetics (TRICKS) sequence and DSA in the diagnosis of spinal dural arteriovenous fistulas (SDAVFs) in our institution.

METHODS

This is a retrospective cohort study of 27 patients who had a TRICKS MRI followed by a DSA for the diagnosis of their SDAVFs between November 2003 and November 2021.

RESULTS

A total of 19 (70.4%) patients were positive for a SDAVF on both TRICKS MRI and DSA. Out of those 19, 9 (47.4%) were in the exact location on both TRICKS MRI and DSA whereas 10 (52.6%) were in different locations. With respect to the 10 patients who had discrepancies in their SDAVF localization between the 2 modalities, 9 (90%) patients had a 1-level difference and 1 (10%) had a 2-level difference.

CONCLUSIONS

TRICKS MRI represents an accurate screening tool to be performed before a spinal DSA in order to guide the interventionalist to focus on the correct level ±2 levels; this extra noninvasive screening tool will decrease the risk of a kidney injury from an overuse of contrast and minimize the fluoroscopy/radiation overexposure.

A comparative study of transradial versus transfemoral approach for flow diversion

PURPOSE

Data in neurointerventional literature is extremely limited regarding the safety and efficacy of flow diversion using transradial access (TRA). We aim to demonstrate the safety and efficacy of intracranial aneurysm treatment with the Pipeline Embolization Device (PED) using TRA compared to transfemoral access (TFA).

METHODS

We conducted a retrospective analysis of a prospectively maintained database and identified 79 consecutive patients who underwent neuroendovascular embolization for cerebral aneurysms using the PED from April 2018 through October 2019. Patients were divided into 2 groups: TRA (32 patients) and TFA (47 patients). A comparative analysis was performed between the two groups.

RESULTS

There was no significant difference in postoperative intracranial hemorrhage (p>.99), symptomatic ischemic stroke (p=.512), access site complications (p=.268), or other complications (p=.512). However, there was a significant increase in overall complications (14.9% vs. 0.0%, p=.038) and procedure duration (71.4 min ± 31.2 vs. 58.5 ± 20.3, p=.018) in the TFA group. There was no significant difference in complete occlusion at latest follow-up (19/25, 76.0% vs. 35/40, 87.5%; p=.311), 6-month follow-up (17/23, 73.9% vs. 33/38, 86.8%; p=.303), or 12-month follow-up (8/8, 100.0% vs. 5/6, 83.3%; p=.429). There was also no significant difference in rate of retreatment (p>.99), morbidity (p=.512), mortality (p>.99), latest follow-up (p=.985), or loss of follow-up (p=.298).

CONCLUSIONS

The feasibility and efficacy of flow diversion with the PED via TRA for the treatment of intracranial aneurysms is comparable to TFA. Widespread adoption of this approach may be facilitated by improvements in device navigation and manipulation via radial-specific engineering.

Carotid cutdown for mechanical thrombectomy in the setting of intravenous tissue plasminogen activator: A technical report

Acute ischemic stroke (AIS) is a leading cause of mortality and morbidity in the world. Patients are usually treated with endovascular methods and access is often gained trans-femoral or trans-radial. In patients with difficult anatomy, in rare cases the approach must be done trans-cervical. Our case illustrates a patient who received IVTPA prior to attempted endovascular treatment, leading to a direct carotid cutdown for mechanical thrombectomy. Our patient presented with a left M1 occlusion and had received intravenous thrombolytic at the presentation of his symptoms. Due to unfavorable anatomy and tortuous aortic arch, conventional access could not be obtained. In order to achieve reperfusion while maintaining hemostasis, a decision was made to perform an open carotid cutdown to catherize the left internal carotid artery to successfully retrieve the thrombus. This resulted in a TICI2B revascularization. This is the first reported case of direct carotid access in the setting of acute ischemic stroke with IVTPA. Open technique allowed us to maintain hemostasis while bypassing the tortuous arch and achieving reperfusion and give the patient the best chance for a functional recovery.

Battle-Tested Guidelines and Operational Protocols for Neurosurgical Practice in Times of a Pandemic: Lessons Learned from COVID-19

The COVID-19 outbreak has led to fundamental disruptions of health care and its delivery with sweeping implications for patients and physicians of all specialties, including neurosurgery. In an effort to conserve hospital resources, neurosurgical procedures were classified into tiers to determine which procedures have to be performed in a timely fashion and which ones can be temporarily suspended to aid in the hospital's reallocation of resources when equipment is scarce. These guidelines were created quickly based on little existing evidence, and thus were initially variable and required refinement. As the early wave can now be assessed in retrospect, the authors describe the lessons learned and the protocols established based on published global evidence to continue to practice neurosurgery sensibly and minimize disruptions. These operational protocols can be applied in a surge of COVID-19 or another airborne pandemic.

Posterior circulation tandem occlusions: Classification and techniques

BACKGROUND

Posterior circulation tandem occlusions are poorly characterized in current literature. Data regarding endovascular approaches and outcomes in this patient subgroup is extremely limited.

METHODS

We conducted a retrospective analysis of a prospectively maintained database and identified 17 patients with posterior circulation tandem occlusions who underwent mechanical thrombectomy between 2014 and 2019.

RESULTS

Of 17 patients with posterior circulation tandem occlusion, the mean age was 55.76 ± 11.8 with 35.3% female. The mean NIHSS score on presentation was 17.2 ± 9.2. Tissue plasminogen activator was administered in 7 (41.2%) patients, stent-retrievers alone were used in 2 (11.8%), aspiration catheters alone were used in 2 (11.8%), a combination was used 12 (70.6%), and a self-expandable stent in 5 (29.4%). The mean number of device passes was 2.24 ± 2.02, recanalization failure occurred in 4 (23.5%) patients, the mean time from stroke onset to puncture was 6.9 ± 2.4 h, and the mean time from puncture to recanalization was 59.3 ± 26.6 min. Postprocedural symptomatic ICH occurred in 1 (5.9 %) patient, periprocedural ICH/SAH occurred in 2 (11.8%), periprocedural distal emboli occurred in 0 (0%), periprocedural vessel dissection occurred in 1 (5.9%), and periprocedural vessel perforation occurred in 1 (5.9%) patient. TICI score>2b was achieved in 13 (76.5%) patients. An improvement in NIHSS>3 at discharge occurred in 10 (58.8%) patients, and good outcomes (mRS score < 2) occurred in 7 (41.2%). The mean length of stay was 11.6 ± 12.2 days, and the mortality rate was 41.2%.

CONCLUSION

Endovascular intervention with mechanical thrombectomy is safe and feasible in patients with posterior circulation tandem occlusions.

The impact of the implementation of a mobile stroke unit on a stroke cohort

BACKGROUND

Mobile stroke units (MSUs), specialized ambulances with a built-in computed tomography (CT) scanner and telemedicine connected stroke team, have been on the rise in recent years largely due to the 'time is brain' concept. We aim to report our initial experience since establishing our MSU, the first unit in the Tri-state area, and assess its impact on the stroke standards of care timeline.

METHODS

We conducted a retrospective analysis of a prospectively maintained database of all MSU dispatched cases from August 2019 to March 2020.

RESULTS

Of 195 MSU responses, 101 were treated and transported by the MSU. The mean time (hr:mm) of dispatch to scene arrival was 0:07+0:03, scene arrival to CT start was 0:10+0:03, CT start to teleneuro start was 0:05+0:03, teleneuro start to scene departure was 0:06+0:05, scene departure to hospital arrival was 0:12+0:06, and hospital arrival to arterial puncture was 2:59+1:01. The mean time of dispatch to arterial puncture was 3:34+1:02. The mean teleneuro consult duration was 0:04+0:02. The mean time of last know well (LKW) to tPA administration was 1:28+0:48 with 4 (57.1 %) patients receiving tPA within 60 min of LKW and 5 (71.4 %) patients receiving tPA within 90 min. The mean time of dispatch to tPA was 0:37+0:09 and scene arrival to tPA administration was 0:28+0:07.

CONCLUSION

MSUs may expedite each step along the stroke standards of care. In theory, this should drastically improve functional outcomes. However, the impact on functional outcomes or reductions in stroke-related morbidity is still unknown.

Transradial approach for diagnostic cerebral angiograms in the elderly: a comparative observational study

Background

The transradial approach (TRA) reduces mortality, morbidity, access site complications, hospital cost, and length of stay while maximizing patient satisfaction. We aimed to assess the technical success and safety of TRA for elderly patients (aged ≥75 years).

Methods

A retrospective chart review and comparative analysis was performed for elderly patients undergoing a diagnostic cerebral angiogram performed via TRA versus transfemoral approach (TFA). Also, a second comparative analysis was performed among the TRA cohort between elderly patients and their younger counterparts.

Results

Comparative analysis in the elderly (TRA vs TFA) showed no significant differences for contrast dose per vessel (43.7 vs 34.6 mL, P=0.106), fluoroscopy time per vessel (5.7 vs 5.2 min, P=0.849), procedure duration (59.8 vs 65.2 min, P=0.057), conversion rate (5.8% vs 2.9%, P=0.650), and access site complications (2.3% vs 2.9%, P=1.00). Radiation exposure per vessel (18.9 vs 51.9 Gy cm2, P=0.001) was significantly lower in the elderly TRA group.

The second comparison (TRA in elderly vs TRA in the young) showed no significant differences for contrast dose per vessel (43.7 vs 37.8 mL, P=0.185), radiation exposure per vessel (18.9 vs 16.5 Gy cm2, P=0.507), procedure duration (59.8 vs 58.3 min, P=0.788), access site complication (2.3% vs 1.7%, P=0.55), and conversation rate (5.8% vs 1.8%, P=0.092). A trend for prolonged fluoroscopy time per vessel (5.7 vs 4.7 min, P=0.050) was observed in the elderly TRA group.

Conclusions

TRA is a technically feasible and safe option for diagnostic neurointerventional procedures in the elderly. Our small elderly cohort was not powered enough to show a significant difference in terms of access site complications between TRA and TFA.

Analysis of the utility of early MRI/MRA in 400 patients with spontaneous intracerebral hemorrhage

OBJECTIVE

MRI and MRA studies are routinely obtained to identify the etiology of intracerebral hemorrhage (ICH). The diagnostic yield of MRI/MRA in the setting of an acute ICH, however, remains unclear. The authors’ goal was to determine the utility of early MRI/MRA in detecting underlying structural lesions in ICH and to identify patients in whom additional imaging during hospitalization could safely be foregone.

METHODS

The authors reviewed data obtained in 400 patients with spontaneous ICH diagnosed on noncontrast head CT scans who underwent MRI/MRA between 2015 and 2017 at their institution. MRI/MRA studies were reviewed to identify underlying lesions, such as arteriovenous malformations, aneurysms, cavernous malformations, arteriovenous fistulas, tumors, sinus thrombosis, moyamoya disease, and abscesses.

RESULTS

The median patient age was 65 ± 15.8 years. Hypertension was the most common (72%) comorbidity. Structural abnormalities were detected on MRI/MRA in 12.5% of patients. Structural lesions were seen in 5.7% of patients with basal ganglia/thalamic ICH, 14.1% of those with lobar ICH, 20.4% of those with cerebellar ICH, and 27.8% of those with brainstem ICH. Notably, the diagnostic yield of MRI/MRA was 0% in patients > 65 years with a basal ganglia/thalamic hemorrhage and 0% in those > 85 years with any ICH location, whereas it was 37% in patients < 50 years and 23% in those < 65 years. Multivariate analysis showed that decreasing age, absence of hypertension, and non–basal ganglia/thalamic location were predictors of finding an underlying lesion.

CONCLUSIONS

The yield of MRI/MRA in ICH is highly variable, depending on patient age and hemorrhage location. The findings of this study do not support obtaining early MRI/MRA studies in patients ≥ 65 years with basal ganglia/thalamic ICH or in any ICH patients ≥ 85 years. In all other situations, early MRI/MRA remains valuable in ruling out underlying lesions.

Access Through the Anatomical Snuffbox for Neuroendovascular Procedures: A Single Institution Series

BACKGROUND

Distal transradial catheterization in the anatomic snuffbox is an alternate route of access that has started to gain consideration for neuroendovascular procedures.

OBJECTIVE

To assess the feasibility and outcomes and present our institution's experience in performing neuroendovascular procedures via distal transradial access (dTRA).

METHODS

We conducted a retrospective analysis and identified 120 patients who underwent consecutive neuroendovascular procedures via dTRA in the anatomic snuffbox. Data collection was performed on indication for procedure, sheath size, number of vessels selectively catheterized, fluoroscopy time, procedure duration, radiation exposure, conversion to femoral approach, access site complication, and procedure success.

RESULTS

Of 120 patients with an average age of 54.7 yr ± 14.7, 73 (60.8%) underwent diagnostic angiograms, 38 (31.7%) underwent follow-up angiograms, and 9 (7.5%) underwent therapeutic procedures. The overall mean number of vessels catheterized was 2.5 ± 0.1 per procedure, the mean procedure time was 68.3 min ± 43.4, the mean fluoroscopy time was 10.8 min ± 7.6, the mean contrast dose was 70.6 mL ± 39.1, and the mean radiation exposure was 27 672.2 mGycm2 ± 42 728.4. Successfully completed therapeutic procedures included aneurysm 1 (0.8%), arteriovenous malformation (AVM)/arteriovenous fistula/carotid cavernous fistula 7 (5.8%), and 1 (0.8%) other treatment. Three patients (2.5%) required adjunct transfemoral endovenous access for AVM embolization. Two minor complications (1.67%) were a local wrist hematoma and a radial artery vasospasm without any sequelae.

CONCLUSION

Distal radial artery catheterization in the anatomic snuffbox is a safe and effective access site to perform neuroendovascular procedures. Complications and conversion rate are low making it a safe alternative.

Coil Embolization of Wide-Neck Bifurcation Aneurysms via Shouldering and Framing: A Safe Alternative to Conventional Techniques

OBJECTIVE

Double stent-assisted coiling of wide-neck bifurcation aneurysms (WNBAs) can be technically challenging with high thromboembolic rates. Single stent-assisted coiling (SSAC) decreases procedural complexity and thromboembolic risk but increases risk of coil prolapse and recanalization. In this study, we present our institution's experience with SSAC of WNBA performed via a "shouldering" and "framing" with a single Atlas stent and a spherical 3-dimensional (3D) Stryker coil.

METHODS

A retrospective review of 35 patients who underwent SSAC of WNBA performed via a shouldering and framing with a single Atlas stent and a spherical 3D Stryker coil from 2018 to 2019. Data collection were performed on baseline demographics, clinical presentation, aneurysm characteristics, angiographic and functional outcomes, and perioperative and postoperative complications.

RESULTS

Of 35 patients, the mean age was 59.9 ± 11.6 years and 25/35 (71.4%) were women. The mean aneurysm diameter was 6.3 ± 3.4 mm, the mean neck size was 3.9 ± 1.3 mm, and the mean dome-to-neck ratio was 1.5 ± 0.6. Initial complete/near-complete occlusion was demonstrated in 30/35 (85.7%) patients. On angiographic follow-up at a mean of 6 months, 9/24 (37.5%) patients showed progressive thrombosis, 13/24 (54.2%) showed stable occlusion, and 2/24 (8.5) showed recanalization. Thromboembolic events occurred in 2/35 (5.7%) patients, intraoperative technical complications occurred in 2/35 (5.7%) patients, and access-site complications occurred in 2/35 (5.7%) patients. The were no cases of retreatment, rehemorrhage, or procedural-related permanent morbidity or mortality.

CONCLUSIONS

Coil embolization performed via shouldering with a single Atlas stent and framing with a spherical 3D Stryker coil is a feasible, safe, and effective neuroendovascular treatment for WNBAs.

Endovascular robotic: feasibility and proof of principle for diagnostic cerebral angiography and carotid artery stenting

Background

Robots in surgery aid in performing delicate, precise maneuvers that humans, with inherent physical abilities, may be limited to perform. The CorPath 200 system is FDA approved and is being implemented in the US for interventional cardiology procedures. CorPath GRX robotic-assisted platform is the next-generation successor of CorPath 200.

Objective

To discuss the feasibility and early experience with the use of the CorPath GRX robotic-assisted platform for neuroendovascular procedures, including transradial diagnostic cerebral angiograms and transradial carotid artery stenting.

Methods

The cases of 10 consecutive patients who underwent neuroendovascular robotic-assisted procedures between December 1, 2019 and December 30, 2019, are presented.

Results

Seven patients underwent elective diagnostic cerebral angiography, and three patients underwent carotid artery angioplasty and stenting using the CorPath GRX robotic-assisted platform. All procedures were performed successfully, and no complications were encountered. Conversion to manual control occurred in three diagnostic cases because of a bovine arch that was previously not known. The fluoroscopy time and the procedure time continued to improve with subsequent procedures as we streamlined the workflow.

Conclusion

This series demonstrates the early use of this technology. It could potentially be used in the near future for acute stroke interventions in remote geographic locations and in places where a neurointerventionalist is not available.

Pipeline for Distal Cerebral Circulation Aneurysms

BACKGROUND

Pipeline embolization device (PED; Medtronic, Dublin, Ireland) utilization is not limited to the treatment of giant wide-necked aneurysms. It has been expanded to handle small blisters, fusiforms, and dissecting intracranial aneurysms.

OBJECTIVE

To report the use of the PED in various off-label distal cerebral circulation (DCC) arteries with a follow-up to assess clinical outcomes.

METHODS

Between 2011 and 2016, of 437 consecutive patients, 23 patients with aneurysms located in DCCs were treated with PED. Data on patient presentation, aneurysm characteristics, procedural outcomes, postoperative course, and aneurysm occlusion were gathered. To control confounding, we used multivariable logistic regression and propensity score conditioning.

RESULTS

A total of 437 patients (mean age 52.12 years; 62 women [14.2%]) underwent treatment with PED in our institution. Twenty-three of 437 (5.2%) received a pipeline in a distal artery: 11/23 middle cerebral artery, 6/23 posterior cerebral artery, 3/23 anterior cerebral artery (A1/A2, pericallosal artery), and 3/23 posterior inferior cerebellar artery. Twenty percent of the aneurysms were treated in the past, 10% had previously ruptured, and 5.9% ruptured at presentation to our hospital. The mean aneurysm size was 9.0 ± 6 mm. The mean follow-up was 12 mo (SD = 12.5). In multivariable logistic regression, no associations were found between PED deployment in DCCs and aneurysm occlusion or thromboembolic complications. PED use in DCC was associated with a good clinical outcome. Twenty-two people of 23 (95%) had a good clinical outcome in the latest follow-up.

CONCLUSION

Treatment of DCC aneurysms with PED is technically challenging mainly because of the small caliber and tortuosity of the parent arteries. The results of this study further support the safety of flow diverters in the treatment of various distal aneurysms.