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. 2024 Feb 1;94(2):369-378.
doi: 10.1227/neu.0000000000002689. Epub 2023 Sep 21.

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

Richard Drexler  1 , Thomas Sauvigny  1 , Tobias F Pantel  1 , Franz L Ricklefs  1 , Joshua S Catapano  2 , John E Wanebo  2 , Michael T Lawton  2 , Aminaa Sanchin  3 , Nils Hecht  3 , Peter Vajkoczy  3 , Kunal Raygor  4 , Daniel Tonetti  4 , Adib Abla  4 , Kareem El Naamani  5 , Stavropoula I Tjoumakaris  5 , Pascal Jabbour  5 , Brian T Jankowitz  6 , Mohamed M Salem  6 , Jan-Karl Burkhardt  6 , Arthur Wagner  7 , Maria Wostrack  7 , Jens Gempt  1   7 , Bernhard Meyer  7 , Michael Gaub  8 , Justin R Mascitelli  8 , Philippe Dodier  9 , Gerhard Bavinzski  9 , Karl Roessler  9 , Nico Stroh  10 , Matthias Gmeiner  10 , Andreas Gruber  10 , Eberval G Figueiredo  11 , Antonio Carlos Samaia da Silva Coelho  11 , Anatoliy V Bervitskiy  12 , Egor D Anisimov  12 , Jamil A Rzaev  12 , Harald Krenzlin  13 , Naureen Keric  13 , Florian Ringel  13 , Dougho Park  14 , Mun-Chul Kim  14 , Eleonora Marcati  15 , Marco Cenzato  15 , Manfred Westphal  1 , Lasse Dührsen  1
Affiliations

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

Richard Drexler et al. Neurosurgery. .

Abstract

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.

Trial registration: ClinicalTrials.gov NCT00502994.

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Figures

FIGURE 1.
FIGURE 1.
Variations in the proportion of benchmark cases performed across the 15 centers. UIA, unruptured intracranial aneurysms.
FIGURE 2.
FIGURE 2.
Stacked bar charts of mRS results at admission, discharge, 6 months, 12 months, and 24 months in the A, benchmark cohort and B, nonbenchmark cohort after surgical clipping. mRS, modified Rankin scale.
FIGURE 3.
FIGURE 3.
Representation of occlusion rates from time of discharge until 24 months after surgical clipping. Aneurysms of the posterior circulation and the posterior communicating artery were excluded in this analysis.
See this image and copyright information in PMC

References

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