Craniotomy improves outcomes for cranial subdural empyemas: computed tomography-era experience with 699 patients.

OBJECTIVE: Uncertainty regarding the best surgical management for subdural empyemas (SDEs) continues. Our unit has considered craniotomy the preferred method of surgical drainage for all cranial SDEs since 1988. We performed an analysis of our previously published, computed tomography-era, experience with 699 patients.
METHODS: Two analyses of the database (1983-1997) were performed. First, analysis of the periods from 1983 to 1987 and from 1988 to 1997 was performed. Second, analysis of the composite database was performed. Outcomes were compared for possible outcome predictors by univariate analysis. Multivariate analysis was used to identify variables that contributed independently to outcomes, using stepwise discriminant analysis.
RESULTS: Significant correlations between the analyzed periods with respect to outcome and type of surgery (P = 0.001) were noted. Analysis of the entire database (1983-1997) revealed a significant relationship between outcome and surgery type (P = 0.05). Pairwise comparison of limited procedures such as burr holes or craniectomies with wide-exposure surgical procedures such as primary craniotomies or procedures proceeding to full craniotomies indicated significant correlation with outcomes (P = 0.027). Reoperation and morbidity rates were increased with limited procedures. Stepwise discriminant analyses revealed that the type of surgery was correlated with outcomes (P = 0.0008, partial r(2) = 0.034).
CONCLUSION: Craniotomy was determined to be the surgical procedure of choice for treatment of cranial SDEs, allowing complete evacuation of the pus and, more importantly, decompressing the underlying cerebral hemisphere. Limited procedures such as burr holes or craniectomies may be performed for patients in septic shock, for patients with parafalcine empyemas, or for children with SDEs secondary to meningitis.