Predictors of Surgical Site Infection After Nonemergent Craniotomy: A Nationwide Readmission Database Analysis

Objective: Surgical site infections (SSIs) carry significant patient morbidity and mortality and are a major source of readmissions after craniotomy. Because of their deleterious effects on health care outcomes and costs, identifying modifiable risk factors holds tremendous value. However, because SSIs after craniotomy are rare and most existing data comprise single-institution studies with small sample sizes, many are likely underpowered to discern for such factors. The objective of this study was to use a large hetereogenous patient sample to determine SSI incidence after nonemergent craniotomy and identify factors associated with readmission and subsequent need for wound washout. Methods: We used the 2010–2014 Nationwide Readmissions Database cohorts to discern for factors predictive of SSI and washout. Results: We identified 93,920 nonemergent craniotomies. There were 2079 cases of SSI (2.2%) and 835 reoperations for washout (0.89%) within 30 days of index admission and there were 2761 cases of SSI (3.6%) and 1220 reoperations for washout (1.58%) within 90 days. Several factors were predictive of SSI in multivariate analysis, including tumor operations, external ventricular drain (EVD), age, length of stay, diabetes, discharge to an intermediate-care facility, insurance type, and hospital bed size. Many of these factors were similarly implicated in reoperation for washout. Conclusions: SSI incidence in neurosurgery is low and most readmissions occur within 30 days. Several factors predicted SSI after craniotomy, including operations for tumor, younger age, hospitalization length, diabetes, discharge to institutional care, larger hospital bed size, Medicaid insurance, and presence of an EVD. Diabetes and EVD placement may represent modifiable factors that could be explored in subsequent prospective studies for their associations with cranial SSIs.