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

Richard Drexler, Department of Neurosurgery, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
Thomas Sauvigny, Department of Neurosurgery, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
Tobias F. Pantel, Department of Neurosurgery, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
Franz L. Ricklefs, Department of Neurosurgery, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
Joshua S. Catapano, Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA.
John E. Wanebo, Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA.
Michael T. Lawton, Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, USA.
Aminaa Sanchin, Department of Neurosurgery, Charité - Universitätsmedizin Berlin, Berlin, Germany.
Nils Hecht, Department of Neurosurgery, Charité - Universitätsmedizin Berlin, Berlin, Germany.
Peter Vajkoczy, Department of Neurosurgery, Charité - Universitätsmedizin Berlin, Berlin, Germany.
Kunal Raygor, Department of Neurological Surgery, University of California, San Francisco, San Francisco, California, USA.
Daniel Tonetti, Department of Neurological Surgery, University of California, San Francisco, San Francisco, California, USA.
Adib Abla, Department of Neurological Surgery, University of California, San Francisco, San Francisco, California, USA.
Kareem El Naamani, Department of Neurological Surgery, Thomas Jefferson University Hospital, Philadelphia, Pennsylvania, USA.
Stavropoula I. Tjoumakaris, Department of Neurological Surgery, Thomas Jefferson University Hospital, Philadelphia, Pennsylvania, USA.
Pascal Jabbour, Department of Neurological Surgery, Thomas Jefferson University Hospital, Philadelphia, Pennsylvania, USA.
Brian T. Jankowitz, Department of Neurosurgery, Hospital of the University of Pennsylvania, Pennsylvania Medicine, Philadelphia, Pennsylvania, USA.
Mohamed M. Salem, Department of Neurosurgery, Hospital of the University of Pennsylvania, Pennsylvania Medicine, Philadelphia, Pennsylvania, USA.
Jan-Karl Burkhardt, Department of Neurosurgery, Hospital of the University of Pennsylvania, Pennsylvania Medicine, Philadelphia, Pennsylvania, USA.
Arthur Wagner, Department of Neurosurgery, Klinikum rechts der Isar, School of Medicine, Technical University of Munich (TUM), Munich, Germany.
Maria Wostrack, Department of Neurosurgery, Klinikum rechts der Isar, School of Medicine, Technical University of Munich (TUM), Munich, Germany.
Jens Gempt, Department of Neurosurgery, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
Bernhard Meyer, Department of Neurosurgery, Klinikum rechts der Isar, School of Medicine, Technical University of Munich (TUM), Munich, Germany.
Michael Gaub, Department of Neurosurgery, University of Texas Health and Science Center at San Antonio, San Antonio, Texas, USA.
Justin R. Mascitelli, Department of Neurosurgery, University of Texas Health and Science Center at San Antonio, San Antonio, Texas, USA.
Philippe Dodier, Department of Neurosurgery, Medical University of Vienna, Vienna, Austria.
Gerhard Bavinzski, Department of Neurosurgery, Medical University of Vienna, Vienna, Austria.
Karl Roessler, Department of Neurosurgery, Medical University of Vienna, Vienna, Austria.
Nico Stroh, Department of Neurosurgery, Kepler University Hospital, Johannes Kepler University, Linz, Austria.
Matthias Gmeiner, Department of Neurosurgery, Kepler University Hospital, Johannes Kepler University, Linz, Austria.
Andreas Gruber, Department of Neurosurgery, Kepler University Hospital, Johannes Kepler University, Linz, Austria.

Document Type

Article

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.

Publication Date

9-21-2023

Publication Title

Neurosurgery

E-ISSN

1524-4040

Volume

94

Issue

2

First Page

369

Last Page

78

PubMed ID

37732745

Digital Object Identifier (DOI)

10.1227/neu.0000000000002689

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