The Impact of Surgical Experience on Major Intraoperative Aneurysm Rupture and Their Consequences on Outcome: A Multivariate Analysis of 538 Microsurgical Clipping Cases

Abstract

The incidence and associated mortality of major intraoperative rupture (MIOR) in intracranial aneurysm surgery is diverse. One possible reason is that many studies failed to consider and properly adjust the factor of surgical experience in the context. We conducted this study to clarify the role of surgical experience on MIOR and associated outcome. 538 consecutive intracranial aneurysm surgeries performed on 501 patients were enrolled in this study. Various potential predictors of MIOR were evaluated with stratified analysis and multivariate logistic regression. The impact of surgical experience and MIOR on outcome was further studied in a logistic regression model with adjustment of each other. The outcome was evaluated using the Glasgow Outcome Scale one year after the surgery. Surgical experience and preoperative Glasgow Coma Scale (GCS) were identified as independent predictors of MIOR. Experienced neurovascular surgeons encountered fewer cases of MIOR compared to novice neurosurgeons (MIOR, 18/225, 8.0% vs. 50/313, 16.0%, P = 0.009). Inexperience and MIOR were both associated with a worse outcome. Compared to experienced neurovascular surgeons, inexperienced neurosurgeons had a 1.90-fold risk of poor outcome. On the other hand, MIOR resulted in a 3.21-fold risk of unfavorable outcome compared to those without it. Those MIOR cases managed by experienced neurovascular surgeons had a better prognosis compared with those managed by inexperienced neurosurgeons (poor outcome, 4/18, 22% vs. 30/50, 60%, P = 0.013).

Fig 1. The impact of surgical experience and MIOR on outcome.

The experienced surgeon without MIOR was set to be the reference group. Inexperienced surgeon encountered a 1.90-fold risk for poor outcome, while MIOR yielded a 3.21-fold risk. The combined risk of inexperience and MIOR for poor outcome was 6.10 times of the reference group. MIOR, major intraoperative rupture; OR, odds ratio.

Fig 2. The risk of MIOR and associated poor outcome between different surgical experience groups.

The risk of MIOR (total bars) from inexperienced neurosurgeons doubled those from experienced neurovascular surgeons (16% vs 8%, P = 0.009). The risk of poor outcome with MIOR (black bars) was 60% in the inexperienced neurosurgeon group, and 22% in the experienced neurovascular surgeon group (P = 0.013).