Faculty Bibliography

Despite advances in endovascular techniques, microsurgery continues to play an important role in the treatment of cerebral aneurysms. This article reviews the history of surgical treatment of intracranial aneurysms and the evolving role of microsurgery in the endovascular era. Although endovascular tools and techniques have changed significantly since the placement of the first Guglielmi coils in 1990, with the development of endoluminal flow-diverting stents and now endosaccular flow-diverting devices, microsurgical treatment of aneurysms has also continued to evolve. Since the first treatment with Hunterian ligation by Horsley in the 1800s, surgical treatment of intracranial aneurysms has advanced significantly beginning with the introduction of the microscope and microsurgical techniques in the 1950s. More recent advances in microsurgical treatment of aneurysms include microsurgical adjuncts, such as indocyanine green angiography, adenosine, and the exoscope, as well as tailored craniotomies, retractorless surgery, and novel bypass constructs for complex aneurysms. Microsurgery continues to play an important role in the endovascular era.

BACKGROUND:Nationwide study results have suggested varying trends in the incidence of aneurysmal subarachnoid hemorrhage (aSAH) over time. Herein, trends over time for aSAH treated at a quaternary care center are compared with low-volume hospitals. METHODS:Cases were retrospectively reviewed for patients with aSAH treated at our institution. Trend analyses were performed on the number of aSAH hospitalizations, treatment type, Charlson Comorbidity Index (CCI), Hunt and Hess grade, aneurysm location, aneurysm type, and in-hospital mortality. The National Inpatient Sample (NIS) was queried to compare the CCI scores of our patients with those of patients in low-volume hospitals (<20 aSAH/year) in our census division. RESULTS: = 0.220, P = 0.24). Mean (standard deviation) CCI for small-volume hospitals treating aSAH within our division was significantly lower than that of our patient population (1.8 [1.6] vs 2.1 [2.0]) for 2012-2015. CONCLUSIONS:A decreasing number of patients were hospitalized with aSAH throughout the study. Compared with patients with aSAH admitted in 2004, those admitted more recently were sicker in terms of preexisting comorbidity and neurologic complexity. These trends could be attributable to the increasing availability of neurointerventional services at smaller-volume hospitals capable of treating healthier patients.

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:Transradial arterial access (TRA) for cerebral diagnostic angiography is associated with fewer access site complications than transfemoral access (TFA). However, concerns about increased procedure time and radiation exposure with TRA may slow its adoption. Our objective was to measure TRA rates of success and fluoroscopy time per vessel after 'radial-first' adoption and to compare these rates to those obtained with TFA. METHODS:We examined 500 consecutive cerebral angiograms on an intent-to-treat basis during the first full year of radial-first adoption, recording patient and procedural characteristics and outcomes. RESULTS:Over a 9-month period at a single center, 457 of 500 angiograms (91.4%) were performed with intent-to-treat via TRA, and 431 cases (86.2%) were ultimately performed via TRA. One patient (0.2%) experienced a temporary neurologic deficit in the TRA group, and none (0%) did in the TFA group (p=0.80). The mean±SD fluoroscopy time per vessel decreased significantly from the first half of the study to the second half for TRA (5.0±3.8 vs 3.4±3.5 min/vessel; p<0.001), while TFA time remained unchanged (3.7±1.8 vs 3.5±1.4 min/vessel; p=0.69). The median fluoroscopy time per vessel for TRA became faster than that for TFA after 150 angiograms. CONCLUSION/CONCLUSIONS:Of 500 consecutive angiograms performed during the first full year of radial-first implementation, 86.2% were performed successfully using TRA. TRA efficiency exceeded that of TFA after 150 angiograms. Concerns about the length of procedure or radiation exposure should not be barriers to TRA adoption.

OBJECTIVE:The Barrow Ruptured Aneurysm Trial (BRAT) was a single-center trial that compared endovascular coiling to microsurgical clipping in patients treated for aneurysmal subarachnoid hemorrhage (aSAH). However, because patients in the BRAT were treated more than 15 years ago, and because there have been advances since then-particularly in endovascular techniques-the relevance of the BRAT today remains controversial. Some hypothesize that these technical advances may reduce retreatment rates for endovascular intervention. In this study, the authors analyzed data for the post-BRAT (PBRAT) era to compare microsurgical clipping with endovascular embolization (coiling and flow diverters) in the two time periods and to examine how the results of the original BRAT have influenced the practice of neurosurgeons at the study institution. METHODS:In this retrospective cohort study, the authors evaluated patients with saccular aSAHs who were treated at a single quaternary center from August 1, 2007, to July 31, 2019. The saccular aSAH diagnoses were confirmed by cerebrovascular experts. Patients were separated into two cohorts for comparison on the basis of having undergone microsurgery or endovascular intervention. The primary outcome analyzed for comparison was poor neurological outcome, defined as a modified Rankin Scale (mRS) score > 2. The secondary outcomes that were compared included retreatment rates for both therapies. RESULTS:Of the 1014 patients with aSAH during the study period, 798 (79%) were confirmed to have saccular aneurysms. Neurological outcomes at ≥ 1-year follow-up did not differ between patients treated with microsurgery (n = 451) and those who received endovascular (n = 347) treatment (p = 0.51). The number of retreatments was significantly higher among patients treated endovascularly (32/347, 9%) than among patients treated microsurgically (6/451, 1%) (p < 0.001). The retreatment rate after endovascular treatment was lower in the PBRAT era (9%) than in the BRAT (18%). CONCLUSIONS:Similar to results from the BRAT, results from the PBRAT era showed equivalent neurological outcomes and increased rates of retreatment among patients undergoing endovascular embolization compared with those undergoing microsurgery. However, the rate of retreatment after endovascular intervention was much lower in the PBRAT era than in the BRAT.

BACKGROUND:Patients with intraventricular hemorrhage (IVH) are at higher risk of hydrocephalus requiring an external ventricular drain and long-term ventriculoperitoneal shunt placement. OBJECTIVE:To investigate whether intraventricular tissue plasminogen activator (tPA) administration in patients with ventricular casting due to IVH reduces shunt dependence. METHODS:Patients from the Post-Barrow Ruptured Aneurysm Trial (PBRAT) database treated for aneurysmal subarachnoid hemorrhage (aSAH) from August 1, 2010, to July 31, 2019, were retrospectively reviewed. Patients with and without IVH were compared. A second analysis compared IVH patients with and without ventricular casting. A third analysis compared patients with ventricular casting with and without intraventricular tPA treatment. The primary outcome was chronic hydrocephalus requiring permanent shunt placement. RESULTS:Of 806 patients hospitalized with aSAH, 561 (69.6%) had IVH. IVH was associated with a higher incidence of shunt placement (25.7% vs 4.1%, P < .001). In multivariable logistic regression analysis, IVH was independently associated with increased likelihood of shunt placement (odds ratio [OR]: 7.8, 95% CI: 3.8-16.2, P < .001). Generalized ventricular casting was present in 80 (14.3%) patients with IVH. In a propensity-score adjusted analysis, generalized ventricular casting was an independent predictor of shunt placement (OR: 3.0, 95% CI: 1.8-4.9, P < .001) in patients with IVH. Twenty-one patients with ventricular casting received intraventricular tPA. These patients were significantly less likely to require a shunt (OR: 0.30, 95% CI: 0.010-0.93, P = .04). CONCLUSION:Ventricular casting in aSAH patients was associated with an increased risk of chronic hydrocephalus and shunt dependency. However, this risk decreased with the administration of intraventricular tPA.

OBJECTIVE:Ophthalmic artery (OA) aneurysms are surgically challenging lesions that are now mostly treated using endovascular procedures. However, in specialized tertiary care centers with experienced neurosurgeons, controversy remains regarding the optimal treatment of these lesions. This study used propensity adjustment to compare microsurgical and endovascular treatment of unruptured OA aneurysms in experienced tertiary and quaternary settings. METHODS:The authors retrospectively reviewed the medical records of all patients who underwent microsurgical treatment of an unruptured OA aneurysm at the University of California, San Francisco, from 1997 to 2017 and either microsurgical or endovascular treatment at Barrow Neurological Institute from 2011 to 2019. Patients were categorized into two cohorts for comparison: those who underwent open microsurgical clipping, and those who underwent endovascular flow diversion or coil embolization. Outcomes included neurological or visual outcomes, residual or recurrent aneurysms, retreatment, and severe complications. RESULTS:A total of 345 procedures were analyzed: 247 open microsurgical clipping procedures (72%) and 98 endovascular procedures (28%). Of the 98 endovascular procedures, 16 (16%) were treated with primary coil embolization and 82 (84%) with flow diversion. After propensity adjustment, microsurgical treatment was associated with higher odds of a visual deficit (OR 8.5, 95% CI 1.1-64.9, p = 0.04) but lower odds of residual aneurysm (OR 0.06, 95% CI 0.01-0.28, p < 0.001) or retreatment (OR 0.12, 95% CI 0.02-0.58, p = 0.008) than endovascular therapy. No difference was found between the two cohorts with regard to worse modified Rankin Scale score, modified Rankin Scale score greater than 2, or severe complications. CONCLUSIONS:Compared with endovascular therapy, microsurgical clipping of unruptured OA aneurysms is associated with a higher rate of visual deficits but a lower rate of residual and recurrent aneurysms. In centers experienced with both open microsurgical and endovascular treatment of these lesions, the treatment choice should be based on patient preference and aneurysm morphology.