Hospital Volume Affects Rates of Complications and Failure To Rescue After Burr Hole Evacuation of Subdural Hematoma

Introduction: Surgical volume may affect complication rates following a given procedure. Furthermore, failure to rescue, defined as the inability to prevent death after a complication, has been shown to affect differences in outcomes between centers. However, the relationship between surgical volume, complications rates, and failure to rescue rates have not been examined for patients undergoing burr hole drainage for subdural hematoma.

Methods: We identified all patients in the Nationwide Inpatient Sample who underwent burr hole drainage for subdural hematoma over a 13-year period. Participating centers were divided into tertiles by the number of times they performed the procedure. The outcomes among patients treated at centers in the highest volume tertile were compared to those of patients treated at centers in the lowest volume tertile. The effect of treatment at a high-volume center versus a low volume center was calculated using propensity score matching while controlling for multiple clinical and demographic characteristics.

Results: 57,258 patients were identified, of whom 16,603 (29.0%) experienced a complication. After propensity score matching, low volume centers had a higher overall complication rate (29.8% vs. 27.9%, p=0.043), representing a modest 6.7% relative increase in overall risk of complications at low-volume centers. This included a 10.1% relative increase in risk of medical complications (p=0.017) at low-volume centers, but no difference in neurologic complications (0.110) or infectious complications (0.477). Low-volume centers had a higher rate of failure to rescue (7.8% vs. 6.7%, p=0.022), corresponding to a significant 16.9% relative increase in risk of death following a complication at low-volume centers.

Conclusion : For patients undergoing burr hole drainage for subdural hematoma, treatment at a low-volume center yields a modest increase in risk of complications, as well as an increase in risk of failure to rescue after a complication occurs.