Objective: The National Healthcare Safety Network classifies breast operations as clean procedures with an expected 1%-2% surgical site infection (SSI) incidence. We assessed differences in SSI incidence following mastectomy with and without immediate reconstruction in a large, geographically diverse population.
Design: Retrospective cohort study.
Patients: Commercially insured women aged 18-64 years with ICD-9-CM procedure or CPT-4 codes for mastectomy from January 1, 2004 through December 31, 2011 METHODS: Incident SSIs within 180 days after surgery were identified by ICD-9-CM diagnosis codes. The incidences of SSI after mastectomy with and without immediate reconstruction were compared using the χ2 test.
Results: From 2004 to 2011, 18,696 mastectomy procedures among 18,085 women were identified, with immediate reconstruction in 10,836 procedures (58%). The incidence of SSI within 180 days following mastectomy with or without reconstruction was 8.1% (1,520 of 18,696). In total, 49% of SSIs were identified within 30 days post-mastectomy, 24.5% were identified 31-60 days post-mastectomy, 10.5% were identified 61-90 days post-mastectomy, and 15.7% were identified 91-180 days post-mastectomy. The incidences of SSI were 5.0% (395 of 7,860) after mastectomy only, 10.3% (848 of 8,217) after mastectomy plus implant, 10.7% (207 of 1,942) after mastectomy plus flap, and 10.3% (70 of 677) after mastectomy plus flap and implant (P<.001). The SSI risk was higher after bilateral compared with unilateral mastectomy with immediate reconstruction (11.4% vs 9.4%, P=.001) than without (6.1% vs 4.7%, P=.021) immediate reconstruction.
Conclusions: SSI incidence was twice that after mastectomy with immediate reconstruction than after mastectomy alone. Only 49% of SSIs were coded within 30 days after operation. Our results suggest that stratification by procedure type facilitates comparison of SSI rates after breast operations between facilities.