Comprehensive Analysis of Post-Pipeline Endothelialization and Remodeling.

BACKGROUND AND PURPOSE: Successful post-flow-diverter endoluminal reconstruction is widely believed to require endothelial overgrowth of the aneurysmal inflow zone. However, endothelialization/neointimal overgrowth is a complex process, over which we currently have very limited influence. Less emphasized is vascular remodeling of the target arterial segment, the dynamic response of the vessel to flow-diverter implantation. This process is distinct from flow modifications in covered branches. It appears that basic angiographic methods allow simple and useful observations. The purpose of this article was to quantitatively evaluate observable postimplantation changes in target vessels following deployment of Pipeline endoluminal constructs. MATERIALS AND METHODS: One hundred consecutive adults with unruptured, previously untreated, nondissecting aneurysms treated with the Pipeline Embolization Device with Shield Technology and the availability of follow-up conventional angiography were studied with 2D DSA imaging. Target vessel size; Pipeline Embolization Device diameter; endothelial thickness; and various demographic, antiplatelet, and device-related parameters were recorded and analyzed. RESULTS: The thickness of neointimal overgrowth (mean, 0.3 [SD, 0.1] mm; range, 0.1-0.7 mm) is inversely correlated with age and is independent of vessel size, smoking status, sex, and degree of platelet inhibition. The decrease in lumen diameter caused by neointimal overgrowth, however, appears counteracted by outward remodeling (dilation) of the target arterial segment. This leads to an increase in the diameter with a corresponding decrease in length (foreshortening) of the implanted Pipeline Embolization Device. This physiologic remodeling process affects optimally implanted devices and is not a consequence of stretching, device migration, vasospasm, and so forth. A direct, linear, statistically significant relationship exists between the degree of observed outward remodeling and the diameter of the implanted Pipeline Embolization Device relative to the target vessel. Overall, remodeled arterial diameters were reduced by 15% (SD, 10%) relative to baseline and followed a normal distribution. Clinically relevant stenosis was not observed. CONCLUSIONS: Vessel healing involves both outward remodeling and neointimal overgrowth. Judicial oversizing could be useful in specific settings to counter the reduction in lumen diameter due to postimplant neointimal overgrowth; however, this overszing needs to be balanced against the decrease in metal coverage accompanying the use of oversized devices. Similar analysis for other devices is essential.

Learning Curve of Robotic End-to-Side Microanastomoses.

BACKGROUND AND OBJECTIVES: Robotics are becoming increasingly widespread within various neurosurgical subspecialties, but data pertaining to their feasibility in vascular neurosurgery are limited. We present our novel attempt to evaluate the learning curve of a robotic platform for microvascular anastomoses. METHODS: One hundred and sixty one sutures were performed and assessed. Fourteen anastomoses (10 robotic [MUSA-2 Microsurgical system; Microsure] and 4 hand-sewn) were performed by the senior author on 1.5-mm caliber tubes and recorded with the Kinevo 900 (Zeiss) operative microscope. We separately compared interrupted sutures (from needle insertion until third knot) and running sutures (from needle insertion until loop pull-down). Average suture timing across all groups was compared using an unpaired Student's t test. Exponential smoothing (α = 0.2) was then applied to the robotic data sets for validation and a second set of t tests were performed. RESULTS: We compared 107 robotic sutures with 54 hand-sewn sutures. There was a significant difference between the average time/stitch for the robotic running sutures (n = 55) and the hand-sewn running sutures (n = 31) (31.2 seconds vs 48.3 seconds, respectively; P-value = .00052). Exponential smoothing (α = 0.2) reinforced these results (37.6 seconds vs 48.3 seconds; P-value = .014625). Average robotic running times surpassed hand-sewn by the second anastomosis (38.8 seconds vs 48.3 seconds) and continued to steadily decrease with subsequent stitches. The average of the robotic interrupted sutures (n = 52) was significantly longer than the hand-sewn (n = 23) (171.3 seconds vs 70 seconds; P = .000024). Exponential smoothing (α = 0.2) yielded similar results (196.7 seconds vs 70 seconds; P = .00001). However, average robotic interrupted times significantly decreased from the first to the final anastomosis (286 seconds vs 105.2 seconds; P = .003674). CONCLUSION: Our results indicate the learning curve for robotic microanastomoses is short and encouraging. The use of robotics warrants further study for potential use in cerebrovascular bypass procedures.

Transpalpebral/Blepharoplasty Incision and Supraorbital Craniotomy for the Treatment of Ethmoidal Dural Arteriovenous Fistulas: A Case Series.

BACKGROUND AND OBJECTIVES: Inherent complex angioarchitecture associated with ethmoidal dural arteriovenous fistulas (dAVFs) can make endovascular treatment methods challenging. Many surgical approaches are accompanied by unfavorable cosmetic results such as facial scarring. Blepharoplasty incision of the eyelid offers a minimal, well-hidden scar compared with other incision sites while offering the surgeon optimal visualization of pathogenic structures. This case series aims to report an initial assessment of the safety and efficacy of supraorbital craniotomy by blepharoplasty transpalpebral (eyelid) incision for surgical disconnection of ethmoidal dAVFs. METHODS: Retrospective chart review was conducted for all patients who underwent blepharoplasty incision and craniotomy for disconnection of ethmoidal dAVFs at our institution between October 2011 and February 2023. Patient charts and follow-up imaging were reviewed to report clinical and angiographic outcomes as well as periprocedural and follow-up complications. RESULTS: Complete obliteration and disconnection of ethmoidal dAVF was achieved in all 6 (100%) patients as confirmed by intraoperative angiogram with no resulting morbidity or mortality. Periprocedural complications included one case of transient nasal cerebrospinal fluid leak that was self-limiting and resolved before discharge without intervention. CONCLUSION: Surgical treatment for ethmoidal dAVFs, specifically by transpalpebral incision and supraorbital craniotomy, is a safe and effective treatment option and affords the surgeon greater access to the floor of the anterior fossa when necessary. In addition, blepharoplasty incision addressed patient concerns for facial scarring compared with other incision sites by creating a more well-hidden, minimal scar in the natural folds of the eyelid for patients with an eyelid crease.

Assessing superficial temporal artery-middle cerebral artery anastomosis patency using FLOW 800 hemodynamics.

OBJECTIVE: The objective of this study was to investigate the use of indocyanine green videoangiography with FLOW 800 hemodynamic parameters intraoperatively during superficial temporal artery-middle cerebral artery (STA-MCA) bypass surgery to predict patency prior to anastomosis performance. METHODS: A retrospective and exploratory data analysis was conducted using FLOW 800 software prior to anastomosis to assess four regions of interest (ROIs; proximal and distal recipients and adjacent and remote gyri) for four hemodynamic parameters (speed, delay, rise time, and time to peak). Medical records were used to classify patients into flow and no-flow groups based on immediate or perioperative anastomosis patency. Hemodynamic parameters were compared using univariate and multivariate analyses. Principal component analysis was used to identify high risk of no flow (HRnf) and low risk of no flow (LRnf) groups, correlated with prospective angiographic follow-ups. Machine learning models were fitted to predict patency using FLOW 800 features, and the a posteriori effect of complication risk of those features was computed. RESULTS: A total of 39 cases underwent STA-MCA bypass surgery with complete FLOW 800 data collection. Thirty-five cases demonstrated flow after anastomosis revascularization and were compared with 4 cases with no flow after revascularization. Proximal and distal recipient speeds were significantly different between the no-flow and flow groups (proximal: 238.3 ± 120.8 and 138.5 ± 93.6, respectively [p < 0.001]; distal: 241.0 ± 117.0 and 142.1 ± 103.8, respectively [p < 0.05]). Based on principal component analysis, the HRnf group (n = 10) was characterized by high-flow speed (> 75th percentile) in all ROIs, whereas the LRnf group (n = 10) had contrasting patterns. In prospective long-term follow-up, 6 of 9 cases in the HRnf group, including the original no-flow cases, had no or low flow, whereas 8 of 8 cases in the LRnf group maintained robust flow. Machine learning models predicted patency failure with a mean F1 score of 0.930 and consistently relied on proximal recipient speed as the most important feature. Computation of posterior likelihood showed a 95.29% chance of patients having long-term patency given a lower proximal speed. CONCLUSIONS: These results suggest that a high proximal speed measured in the recipient vessel prior to anastomosis can elevate the risk of perioperative no flow and long-term reduction of flow. With an increased dataset size, continued FLOW 800-based ROI metric analysis could be used to guide intraoperative anastomosis site selection prior to anastomosis and predict patency outcome.

Femoral versus radial access for middle meningeal artery embolization for chronic subdural hematomas: multicenter propensity score matched study.

BACKGROUND: With transradial access (TRA) being more progressively used in neuroendovascular procedures, we compared TRA with transfemoral access (TFA) in middle meningeal artery embolization (MMAE) for chronic subdural hematoma (cSDH). METHODS: Consecutive patients undergoing MMAE for cSDH at 14 North American centers (2018-23) were included. TRA and TFA groups were compared using propensity score matching (PSM) controlling for: age, sex, concurrent surgery, previous surgery, hematoma thickness and side, midline shift, and pretreatment antithrombotics. The primary outcome was access site and overall complications, and procedure duration; secondary endpoints were surgical rescue, radiographic improvement, and technical success and length of stay. RESULTS: 872 patients (median age 73 years, 72.9% men) underwent 1070 MMAE procedures (54% TFA vs 46% TRA). Access site hematoma occurred in three TFA cases (0.5%; none required operative intervention) versus 0% in TRA (P=0.23), and radial-to-femoral conversion occurred in 1% of TRA cases. TRA was more used in right sided cSDH (58.4% vs 44.8%; P<0.001). Particle embolics were significantly higher in TFA while Onyx was higher in TRA (P<0.001). Following PSM, 150 matched pairs were generated. Particles were more utilized in the TFA group (53% vs 29.7%) and Onyx was more utilized in the TRA group (56.1% vs 31.5%) (P=0.001). Procedural duration was longer in the TRA group (median 68.5 min (IQR 43.1-95) vs 59 (42-84); P=0.038), and radiographic success was higher in the TFA group (87.3% vs 77.4%; P=0.036). No differences were noted in surgical rescue (8.4% vs 10.1%, P=0.35) or technical failures (2.4% vs 2%; P=0.67) between TFA and TRA. Sensitivity analysis in the standalone MMAE retained all associations but differences in procedural duration. CONCLUSIONS: In this study, TRA offered comparable outcomes to TFA in MMAE for cSDH in terms of access related and overall complications, technical feasibility, and functional outcomes. Procedural duration was slightly longer in the TRA group, and radiographic success was higher in the TFA group, with no differences in surgical rescue rates.

General Versus Nongeneral Anesthesia for Middle Meningeal Artery Embolization for Chronic Subdural Hematomas: Multicenter Propensity Score Matched Study.

BACKGROUND AND OBJECTIVES: The choice of anesthesia type (general anesthesia [GA] vs nongeneral anesthesia [non-GA]) in middle meningeal artery embolization (MMAE) procedures for chronic subdural hematomas (cSDH) differs between institutions and left to care team discretion given lack of standard guidelines. We compare the outcomes of GA vs non-GA in MMAE. METHODS: Consecutive patients receiving MMAE for cSDH at 14 North American centers (2018-2023) were included. Clinical, cSDH characteristics, and technical/clinical outcomes were compared between the GA/non-GA groups. Using propensity score matching (PSM), patients were matched controlling for age, baseline modified Rankin Scale, concurrent/prior surgery, hematoma thickness/midline shift, and baseline antiplatelet/anticoagulation. The primary end points included surgical rescue and radiographic success rates (≥50% reduction in maximum hematoma thickness with minimum 2 weeks of imaging). Secondary end points included technical feasibility, procedural complications, and functional outcomes. RESULTS: Seven hundred seventy-eight patients (median age 73 years, 73.2% male patients) underwent 956 MMAE procedures, 667 (70.4%) were non-GA and 280 were GA (29.6%). After running 1:3 PSM algorithm, this resulted in 153 and 296 in the GA and non-GA groups, respectively. There were no baseline/procedural differences between the groups except radial access more significantly used in the non-GA group (P = .001). There was no difference between the groups in procedural technical feasibility, complications rate, length of stay, surgical rescue rates, or favorable functional outcome at the last follow-up. Subsequent 1:1 sensitivity PSM retained the same results. Bilateral MMAE procedures were more performed under non-GA group (75.8% vs 67.2%; P = .01); no differences were noted in clinical/radiographic outcomes between bilateral vs unilateral MMAE, except for longer procedure duration in the bilateral group (median 73 minutes [IQR 48.3-100] vs 54 minutes [39-75]; P < .0001). Another PSM analysis comparing GA vs non-GA in patients undergoing stand-alone MMAE retained similar associations. CONCLUSION: We found no significant differences in radiological improvement/clinical outcomes between GA and non-GA for MMAE.

The Influence of Coagulopathy on Radiographic and Clinical Outcomes in Patients Undergoing Middle Meningeal Artery Embolization as Standalone Treatment for Non-acute Subdural Hematomas.

Middle meningeal artery embolization (MMAE) is emerging as a safe and effective standalone intervention for non-acute subdural hematomas (NASHs); however, the risk of hematoma recurrence after MMAE in coagulopathic patients is unclear. To characterize the impact of coagulopathy on treatment outcomes, we analyzed a multi-institutional database of patients who underwent standalone MMAE as treatment for NASH. We classified 537 patients who underwent MMAE as a standalone intervention between 2019 and 2023 by coagulopathy status. Coagulopathy was defined as use of anticoagulation/antiplatelet agents or pre-operative thrombocytopenia (platelets <100,000/µL). Demographics, pre-procedural characteristics, in-hospital course, and patient outcomes were collected. Thrombocytopenia, aspirin use, antiplatelet agent use, and anticoagulant use were assessed using univariate and multivariate analyses to identify any characteristics associated with the need for rescue surgical intervention, mortality, adverse events, and modified Rankin Scale score at 90-day follow-up. Propensity score-matched cohorts by coagulopathy status with matching covariates adjusting for risk factors implicated in surgical recurrence were evaluated by univariate and multivariate analyses. Minimal differences in pre-operative characteristics between patients with and those without coagulopathy were observed. On unmatched and matched analyses, patients with coagulopathy had higher rates of requiring subsequent surgery than those without (unmatched: 9.9% vs. 4.3%; matched: 12.6% vs. 4.6%; both p < 0.05). On matched multivariable analysis, patients with coagulopathy had an increased odds ratio (OR) of requiring surgical rescue (OR 3.95; 95% confidence interval [CI] 1.68-9.30; p < 0.01). Antiplatelet agent use (ticagrelor, prasugrel, or clopidogrel) was also predictive of surgical rescue (OR 4.38; 95% CI 1.51-12.72; p = 0.01), and patients with thrombocytopenia had significantly increased odds of in-hospital mortality (OR 5.16; 95% CI 2.38-11.20; p < 0.01). There were no differences in follow-up radiographic and other clinical outcomes in patients with and those without coagulopathy. Patients with coagulopathy undergoing standalone MMAE for treatment of NASH may have greater risk of requiring surgical rescue (particularly in patients using antiplatelet agents), and in-hospital mortality (in thrombocytopenic patients).