Faculty Bibliography

BACKGROUND:The coronavirus disease 2019 pandemic necessitated the use of telemedicine for most medical specialties, including neurosurgery, although before the pandemic, neurosurgeons infrequently used telemedicine for outpatient visits. We conducted a patient-centric evaluation of telemedicine in our endovascular neurosurgery practice, covering a 4-month period early in the pandemic. METHODS:Survey e-mails after telemedicine visits were sent to all patients who underwent an outpatient telemedicine visit between March 11, 2020, and June 22, 2020, at an endovascular neurosurgery clinic affiliated with a tertiary care center. RESULTS:Of 140 patients, 65 (46%) completed the e-mail survey. Of the 65 respondents, 35 (54%) agreed or strongly agreed with the statement that even before their telemedicine experience, they thought telemedicine would be a convenient way to receive a neurological consultation. After their telemedicine visit, 47 (72%) agreed or strongly agreed with this statement, and 28 (43%) agreed or strongly agreed that they would prefer telemedicine for future visits. Of the 65 respondents, 61 (94%) rated their telemedicine visit as average or better: 34 (52%) rated it excellent, 12 (18%) rated it above average, and 15 (23%) rated it average. When patients compared their telemedicine visit with a prior in-person clinic visit, only 10 of 44 patients (23%) thought the telemedicine visit was more complicated than an in-person visit, and 21 of 44 (48%) said they would prefer telemedicine for future visits. CONCLUSIONS:Our patients expressed satisfaction with their telemedicine visits, and telemedicine will likely play an important role in future outpatient endovascular neurosurgery consultations.

BACKGROUND:Transradial access (TRA) for neuroendovascular procedures is increasing in prevalence. The safety benefits of TRA at a patient level may be offset at a population level by a paradoxical increase in transfemoral access (TFA) vascular access site complications (VASCs), the so-called "radial paradox." OBJECTIVE:To study the effect of TRA adoption on TFA performance and outcomes in neuroendovascular procedures. METHODS:Data were collected for all procedures performed over a 10-mo period after radial adoption at a single center. RESULTS:Over the study period, 1084 procedures were performed, including 719 (66.3%) with an intent to treat by TRA and 365 (33.7%) with an intent to treat by TFA. Thirty-two cases (4.4%) crossed over from TRA to TFA, and 2 cases (0.5%) crossed over from TFA to TRA. TFA was performed in older patients (mean [standard deviation] TFA, 63 [15] vs TRA, 56 [16] years) using larger sheath sizes (≥7 French; TFA, 56.2% vs TRA, 2.3%) ( P < .001 for both comparisons). Overall, 29 VASCs occurred (2.7%), including 27 minor (TFA, 4.6% [18/395] vs TRA, 1.3% [9/689], P = .002) and 2 major (TFA, 0.3% [1/395] vs TRA, 0.1% [1/689], P > .99) complications. Independent predictors of VASC included TFA (OR 2.8, 95% confidence interval [CI] 1.1-7.4) and use of dual antiplatelet therapy (OR 4.2, 95% CI 1.6-11.1). CONCLUSION:TFA remains an important access route, despite a predominantly radial paradigm, and is disproportionately used in patients at increased risk for VASCs. TFA proficiency may still be achieved in predominantly radial practices without an increase in femoral complications.

BACKGROUND:Although the full transcavernous approach affords extensive mobilization of the oculomotor nerve (OMN) for exposure of the basilar apex and interpeduncular cistern region, this time-consuming procedure requires substantial dural dissection along the anterior middle cranial fossa. OBJECTIVE:To quantify the extent to which limited middle fossa dural elevation affects the carotid-oculomotor window (C-OMW) surgical area during transcavernous exposure after OMN mobilization. METHODS:Four cadaveric specimens were dissected bilaterally to study the C-OMW area afforded by the transcavernous exposure. Each specimen underwent full and limited transcavernous exposure and anterior clinoidectomy (1 procedure per side; 8 procedures). Limited exposure was defined as a dural elevation confined to the cavernous sinus. Full exposure included dural elevation over the gasserian ganglion, extending to the middle meningeal artery and lateral middle cranial fossa. RESULTS:The C-OMW area achieved with the limited transcavernous exposure, compared with full transcavernous exposure, provided significantly less total area with OMN mobilization (22 ± 6 mm2 vs 52 ± 26 mm2, P = .03) and a smaller relative increase in area after OMN mobilization (11 ± 5 mm2 vs 36 ± 13 mm2, P = .03). The increase after OMN mobilization in the C-OMW area after OMN mobilization was 136% ± 119% with a limited exposure vs 334% ± 216% with a full exposure. CONCLUSION:In this anatomical study, the full transcavernous exposure significantly improved OMN mobilization and C-OMW area compared with a limited transcavernous exposure. If a transcavernous exposure is pursued, the difference in the carotid-oculomotor operative corridor area achieved with a limited vs full exposure should be considered.

BACKGROUND:Cerebral arteriovenous malformations (AVMs) with low Spetzler-Martin grades (I and II) are associated with good neurological outcomes after microsurgical resection; however, the use of preoperative embolization for these lesions is controversial. OBJECTIVE:To compare the neurological outcomes of preoperative embolization with no embolization in patients with low-grade AVMs. METHODS:Patients with a Spetzler-Martin grade I or II AVM who underwent microsurgical resection during January 1, 1997, through December 31, 2019, were analyzed. Patients undergoing preoperative embolization were compared with patients not undergoing embolization. A propensity score was constructed from baseline characteristics and used to match intervention (embolization) and control (nonembolization) groups in a 1:1 ratio. The primary outcome was poor neurological status on last follow-up examination, defined as a modified Rankin Scale score >2 and a modified Rankin Scale score worse at follow-up than at the preoperative examination. RESULTS:Of the 603 patients analyzed, 310 (51.4%) underwent preoperative embolization and 293 (48.6%) did not. Patients in the embolization cohort compared with those in the nonembolization cohort had a higher percentage of Spetzler-Martin grade II AVMs (71.6% vs 52.6%, P < .001) and a lower percentage of hemorrhage (41% vs 55%, P = .001). After propensity score matching, no differences were found between paired cohorts (each N = 203) for baseline characteristics with a significant reduction in absolute standardized mean differences. No significant differences were found in primary outcomes between treatment groups in the matched or unmatched cohorts. CONCLUSION:Preoperative embolization of low-grade Spetzler-Martin AVMs is not associated with improved neurological outcomes after microsurgical resection.

BACKGROUND:Middle meningeal artery (MMA) embolization results in fewer treatment failures than surgical evacuation for chronic subdural hematomas (cSDHs). We compared the total 1-year hospital cost for MMA embolization versus surgical evacuation for patients with cSDH. METHODS:Data for patients who presented with cSDHs from January 1, 2018, through May 31, 2020, were retrospectively reviewed. Patients were grouped by initial treatment (surgery vs MMA embolization), and total hospital cost was obtained. A propensity-adjusted analysis was performed. The primary outcome was difference in mean hospital cost between treatments. RESULTS:Of 170 patients, 48 (28%) underwent embolization and 122 (72%) underwent surgery. cSDHs were larger in the surgical (20.5 (6.7) mm) than in the embolization group (16.9 (4.6) mm; P<0.001); and index hospital length of stay was longer in the surgical group (9.8 (7.0) days) than in the embolization group (5.7 (2.4) days; P<0.001). More patients required additional hematoma treatment in the surgical cohort (16%) than in the embolization cohort (4%; P=0.03), and more required readmission in the surgical cohort (28%) than in the embolization cohort (13%; P=0.04). After propensity adjustment, MMA embolization was associated with a lower total hospital cost compared to surgery (mean difference -$32 776; 95% CI -$52 766 to -$12 787; P<0.001). A propensity-adjusted linear regression analysis found that unexpected additional treatment was the only significant contributor to total hospital cost (mean difference $96 357; 95% CI $73 886 to $118 827; P<0.001). CONCLUSIONS:MMA embolization is associated with decreased total hospital cost compared with surgery for cSDHs. This lower cost is directly related to the decreased need for additional treatment interventions.

BACKGROUND:Few reports discuss variables associated with improved outcomes after middle meningeal artery (MMA) embolization for chronic subdural hematomas (cSDHs). We analyzed radiographic evidence of cSDH clearance after MMA embolization to elucidate optimal techniques, hematoma clearance rates, and suitable length of follow-up. METHODS:Patients who underwent MMA embolization for cSDH from January 1, 2018 through December 31, 2020 were analyzed. Patient characteristics, demographics, and technical procedural details were examined. Outcomes for cSDHs analyzed included complete or near-complete resolution at 30, 90, and 180 days following embolization. A multivariable logistic regression analysis identified variables predictive of rapid clearance and resolution of hematomas at 90 days. RESULTS:The study cohort comprised 66 patients with 84 treated cSDHs. The mean (SD) cSDH size differed significantly at 30-day (8.8 (4.3) mm), 90-day (3.4 (3.0) mm), and 180-day (1.0 (1.7) mm) follow-up (p<0.001). More cSDHs had complete or near-complete resolution at 180 days (92%, 67/73) than at 90 (63%, 45/72) and 30 days (18%, 15/84) post-embolization (p<0.001). Only distal embolysate penetration was independently associated with rapid clearance (OR 3.9, 95% CI 1.4 to 11.1; p=0.01) and resolution of cSDHs at 90 days (OR 5.0, 95% CI 1.7 to 14.6; p=0.003). CONCLUSION/CONCLUSIONS:Although 63% of cSDHs with MMA embolization had complete or near-complete resolution by 90 days post-procedure, 92% reached this stage by 180 days. Therefore, 90-day follow-up may be insufficient to determine the effectiveness of MMA embolization for cSDHs, particularly compared with surgical evacuation alone. Also, distal MMA penetration may be associated with more rapid hematoma clearance.

OBJECTIVE:Supplemented Spetzler-Martin grading (Supp-SM), which is the combination of Spetzler-Martin and Lawton-Young grades, was validated as being more accurate than stand-alone Spetzler-Martin grading, but an operability cutoff was not established. In this study, the authors surgically treated intermediate-grade AVMs to provide prognostic factors for neurological outcomes and to define AVMs at the boundary of operability. METHODS:Surgically treated Supp-SM intermediate-grade (5, 6, and 7) AVMs were analyzed from 2011 to 2018 at two medical centers. Worsened neurological outcomes were defined as increased modified Rankin Scale (mRS) scores on postoperative examinations. A second analysis of 2000-2011 data for Supp-SM grade 6 and 7 AVMs was performed to determine the subtypes with improved or unchanged outcomes. Patients were separated into three groups based on nidus size (S1: < 3 cm, S2: 3-6 cm, S3: > 6 cm) and age (A1: < 20 years, A2: 20-40 years, A3: > 40 years), followed by any combination of the combined supplemented grade: low risk (S1A1, S1A2, S2A1), intermediate risk (S2A2, S1A3, S3A1, or high risk (S3A3, S3A2, S2A3). RESULTS:Two hundred forty-six patients had intermediate Supp-SM grade AVMs. Of these patients, 102 had Supp-SM grade 5 (41.5%), 99 had Supp-SM grade 6 (40.2%), and 45 had Supp-SM grade 7 (18.3%). Significant differences in the proportions of patients with worse mRS scores at follow-up were found between the groups, with 24.5% (25/102) of patients in Supp-SM grade 5, 29.3% (29/99) in Supp-SM grade 6, and 57.8% (26/45) in Supp-SM grade 7 (p < 0.001). Patients with Supp-SM grade 7 AVMs had significantly increased odds of worse postoperative mRS scores (p < 0.001; OR 3.7, 95% CI 1.9-7.3). In the expanded cohort of 349 Supp-SM grade 6 AVM patients, a significantly higher proportion of older patients with larger Supp-SM grade 6 AVMs (grade 6+, 38.6%) had neurological deterioration than the others with Supp-SM grade 6 AVMs (22.9%, p = 0.02). Conversely, in an expanded cohort of 197 Supp-SM grade 7 AVM patients, a significantly lower proportion of younger patients with smaller Supp-SM grade 7 AVMs (grade 7-, 19%) had neurological deterioration than the others with Supp-SM grade 7 AVMs (44.9%, p = 0.01). CONCLUSIONS:Patients with Supp-SM grade 7 AVMs are at increased risk of worse postoperative neurological outcomes, making Supp-SM grade 6 an appropriate operability cutoff. However, young patients with small niduses in the low-risk Supp-SM grade 7 group (grade 7-) have favorable postoperative outcomes. Outcomes in Supp-SM grade 7 patients did not improve with surgeon experience, indicating that the operability boundary is a hard limit reflecting the complexity of high-grade AVMs.