Ultrasound-assisted treatment of sternocutaneous fistula in post-sternotomy cardiac surgery patients

Abstract

OBJECTIVES: Using an ultrasonic debridement system (low frequency, 25 kHz), we aimed to completely remove bacterial biofilms and preserve vital sternal tissue and to compare this procedure with conventional surgical therapy. METHODS: In this retrospective study, we evaluated 37 consecutive patients (25 males) between April 2011 and June 2013 in whom sternocutaneous fistula (SCF) was treated with the ultrasound-assisted wound (UAW) system (Group A, n = 18) or with conventional surgical therapy (Group B, n = 19). Treatment in Group A consisted of a complete dissection of the SCF followed by a multistep UAW debridement session after an interval of 3 days. Our final step in both groups was secondary wound closure with a musculocutaneous flap. RESULTS: Patients in both groups were categorized as high risk with respect to several of the known SCF risk factors. In both groups, a similar variety of bacteria were isolated: 61% were gram-positive species, 16.5% were gram-negative species and 10.5% were Candida albicans. Time to secondary wound closure following eradication was significantly shorter in Group A (10 ± 5.4 vs 15 ± 7.1 days in Group B, P = 0.012). Postoperative antibiotic treatment time (16 ± 9.3 vs 22 ± 10.7 days in Group B, P = 0.078) showed a trend in favour of Group A, but the mean hospitalization time (22 ± 12.0 vs 26 ± 14.3 days in Group B, P = 0.34) did not differ between groups. Recurrence of SCF tended to be less frequent in Group A (6 vs 21% in Group B, P = 0.46). In Group B, one infection-related death was noted. The mean follow-up time was 8 ± 2.7 (Group A) and 10 ± 5.7 (Group B) months. CONCLUSIONS: Ultrasonic debridement is a promising adjunct to SCF treatment. In combination with adequate surgical and antimicrobial therapy, we documented good mid-term results in our trial group.