Effectiveness of neurosurgical clip application in patients with aneurysmal subarachnoid hemorrhage

Object. Neurosurgical clip application is the standard method used to prevent rebleeding in patients with aneurysmal subarachnoid hemorrhage (SAH). The authors assessed the magnitude of the reduction in poor outcomes that accompanies a strategy aimed at surgery. Methods. Three hundred forty-six consecutive patients with aneurysmal SAH were studied. The authors estimated the number of surgically treated patients with good outcomes who would have had poor outcomes as a consequence of rebleeding if clip application had not been performed (A). They also assessed the number of patients whose poor outcomes were exclusively caused by operative complications (13). Without an operation some of these patients would have had poor outcomes because of rebleeding (C). The authors represented the number of patients in whom poor outcome was prevented by surgery with the following formula: A - B + C. They assessed the relationships between baseline characteristics of patients and aneurysms and the likelihood that a patient underwent surgery, the risk of operative complications, and the risk of rebleeding. The absolute reduction in the risk of poor outcome found in patients who undergo surgery was 9.7%. This implies that to prevent a poor outcome in one patient, surgery had to be performed in 10. The relative risk of poor outcome following surgery compared with that after conservative treatment was estimated to be 0.81. Logistic regression analysis showed a statistically significant relationship between patient age older than 65 years and the occurrence of operative complications (odds ratio [OR] 2.49; 95% confidence interval [CI] 1.03-6.03), between age older than 65 years and the likelihood of undergoing surgery (OR 0.12; 95% Cl 0.07-0.2), and between a poor clinical condition at admission and the likelihood of undergoing surgery (OR 0.26; 95% Cl 0.14-0.47). The authors did not identify any predictive factors for rebleeding when the Cox proportional hazard model was used. Conclusions. The beneficial effect of a treatment strategy in which the goal is surgery is substantial. If new treatment modalities such as embolization with coils are explored, these should carefully be compared with surgery before they are generally introduced.