Sternocutaneous fistulas after cardiac surgery: incidence and late outcome during a ten-year follow-up.

BACKGROUND: Sternocutaneous fistulas (SCFs) after cardiac surgery represent a complex surgical problem involving multiple hospital admissions, prolonged antibiotic treatment, and repeated debridements. Our objective was to identify the incidence of and risk factors for SCF, and to evaluate long-term survival. METHODS: A total of 12,297 patients underwent sternotomy for cardiac surgery between January 1999 and December 2008, and 32 patients were diagnosed as having SCF during follow-up. Risk factors were identified with multivariate analysis and survival was compared using the log-rank test. RESULTS: The cumulative incidence of SCF at one year was 0.23%. There was no significant difference in mean time from sternal closure after cardiac surgery to intervention for SCF with (n = 9) or without (n = 23) preceding sternal wound infection (SWI); 6.1 +/- 4.2 versus 6.9 +/- 4.6 months, (p = ns). Risk factors for developing SCF were previous SWI (odds ratio [OR] = 15.7), renal failure (OR = 12.5), smoking (OR = 4.7), and use of bone wax during cardiac surgery (OR = 4.2). Negative-pressure wound therapy was applied in 20 cases of extensive SCFs. Five-year survival of SCF patients was 58% +/- 1% as compared with 85% +/- 4% in the control group (p = 0.003). CONCLUSIONS: Sternocutaneous fistula is a devastating diagnosis with significant morbidity and mortality. Previous SWI, renal failure, smoking, and use of bone wax are major risk factors. However, in a majority of patients SCF is not preceded by SWI and our results indicate that SCF may be a foreign body infection that develops in susceptible patients with risk factors for poor wound healing. Negative-pressure wound therapy may be a valuable adjunct in the treatment of extensive SCF.