Unruptured cerebral aneurysm clipping: association of combined open and endovascular expertise with outcomes

Background It is often questioned if one physician can conduct both open and endovascular techniques successfully and safely. Objective To investigate the association of combined open and endovascular expertise with the outcomes of unruptured cerebral aneurysm clipping. Methods We performed a cohort study of 100% of Medicare fee-for-service claims data for elderly patients who underwent surgical clipping for unruptured cerebral aneurysms between 2007 and 2012. To control for confounding we used propensity score conditioning, and controlled for clustering at the physician level. Results During the study, 3247 patients underwent clipping for unruptured cerebral aneurysms, and met the inclusion criteria. Of these, 766 (23.6%) underwent treatment by hybrid neurosurgeons, and 2481 (76.4%) by proceduralists, who performed only clipping. Multivariable regression analysis with propensity score adjustment demonstrated a lack of association of combined practice with 1-year postoperative mortality (OR=0.81; 95% CI 0.51 to 1.28), discharge to rehabilitation (OR=0.95; 95% CI 0.72 to 1.25), length of stay (adjusted difference 0.85 days; 95% CI -0.31 to 2.00), or 30-day readmission rate (OR=1.05; 95% CI 0.80 to 1.39). Higher procedural volume was independently associated with improved outcomes. Conclusions In a cohort of Medicare patients with unruptured aneurysms, we did not demonstrate a difference in mortality, discharge to rehabilitation, or readmission rate between hybrid neurosurgeons and surgeons performing only clipping.