Global Outcomes for Microsurgical Clipping of Unruptured Intracranial Aneurysms: A Benchmark Analysis of 2245 Cases.

BACKGROUND AND OBJECTIVES: Benchmarks represent the best possible outcome and help to improve outcomes for surgical procedures. However, global thresholds mirroring an optimal and reachable outcome for microsurgical clipping of unruptured intracranial aneurysms (UIA) are not available. This study aimed to define standardized outcome benchmarks in patients who underwent clipping of UIA. METHODS: A total of 2245 microsurgically treated UIA from 15 centers were analyzed. Patients were categorized into low- ("benchmark") and high-risk ("nonbenchmark") patients based on known factors affecting outcome. The benchmark was defined as the 75th percentile of all centers' median scores for a given outcome. Benchmark outcomes included intraoperative (eg, duration of surgery, blood transfusion), postoperative (eg, reoperation, neurological status), and aneurysm-related factors (eg, aneurysm occlusion). Benchmark cutoffs for aneurysms of the anterior communicating/anterior cerebral artery, middle cerebral artery, and posterior communicating artery were determined separately. RESULTS: Of the 2245 cases, 852 (37.9%) patients formed the benchmark cohort. Most operations were performed for middle cerebral artery aneurysms (53.6%), followed by anterior communicating and anterior cerebral artery aneurysms (25.2%). Based on the results of the benchmark cohort, the following benchmark cutoffs were established: favorable neurological outcome (modified Rankin scale ≤2) ≥95.9%, postoperative complication rate ≤20.7%, length of postoperative stay ≤7.7 days, asymptomatic stroke ≤3.6%, surgical site infection ≤2.7%, cerebral vasospasm ≤2.5%, new motor deficit ≤5.9%, aneurysm closure rate ≥97.1%, and at 1-year follow-up: aneurysm closure rate ≥98.0%. At 24 months, benchmark patients had a better score on the modified Rankin scale than nonbenchmark patients. CONCLUSION: This study presents internationally applicable benchmarks for clinically relevant outcomes after microsurgical clipping of UIA. These benchmark cutoffs can serve as reference values for other centers, patient registries, and for comparing the benefit of other interventions or novel surgical techniques.

Temporary arterial occlusion (TAO) as independent prognostic factor in unruptured aneurysm surgery: A cohort study.

BACKGROUND: Temporary arterial occlusion (TAO) is a technique widely used in cerebrovascular surgery. However, few studies have evaluated the independent long-term effects of TAO or given detailed information about the complications during in-hospital stay. OBJECTIVE: This study aims to investigate the independent impact of TAO during unruptured intracranial aneurysm surgery on short and long-term outcomes. METHODS: The study included surgical elective patients diagnosed with unruptured aneurysm and indication of microsurgical treatment. Outcome assessment included occurrence of intra-operative (IOC) and post-operative (POC) complications, as well as Glasgow Outcome Scale (GOS) score 6 months after discharge. RESULTS: 114 patients were included and 36 were followed. TAO was associated with POC (OR = 2.08; CI 95% 1.12-3.96; p = 0.01). The group with TAO and intraoperative rupture (IOR) did not differ from the group with TAO without IOR in terms of POC (p = 0.65) and IOC (p = 0.78). IOR (p = 0.16) and number of occlusions (p = 0.23) did not change GOS, but the total time of occlusion was associated with neurologic worsening (p = 0.034) during follow-up. The TAO group had larger aneurysm size and higher frequency of irregular lesions, when compared to the entire study group. Aneurysm location was not associated with POC (p = 0.25), IOC (0.17) or GOS (p = 0.75). CONCLUSION: The location of temporary clip placement and the number of clips did not influence the short- and long-term outcomes of patients with unruptured intracranial aneurysms. However, presence of temporary clips was associated with POC regardless of IOR occurrence and increased total time of occlusion was associated with poor outcomes after 6 months.