Does Antibiotic Irrigation Really Reduce the Risk of Capsular Contracture of the Breast?

Abstract

Awad et al. [1] report a systematic review comparing capsular contracture rates with the type of pocket irrigation. The authors conclude that antibiotic irrigation leads to significantly fewer capsular contractures than saline irrigation. The authors acknowledge that two studies by Pfeiffer et al. [2] and Drinane et al. [3] failed to show a significant advantage for antibiotic pocket irrigation compared with saline. However, with the addition of a cohort of patients, or rather breasts, published in an article by Burkhardt et al., [4] the authors (incorrectly) conclude that the overall rate of capsular contracture was significantly lower in the antibiotic group. It is difficult to compare this study by Burkhardt et al. [4] with the studies by Pfeiffer et al. [2] and Drinane et al. [3] because capsular contractures are reported by breast rather than by patient and each patient received two different treatments. It is therefore necessary to convert the complication rates reported in these more recent studies to per-breast rather than per-patient. Pfeiffer et al. [3] reported 12 capsular contractures among 203 women (406 breasts) who received pocket antibiotic irrigation versus 17 capsular contractures among 211 women (422 breasts) who received saline pocket irrigation. Drinane et al. [4] reported 2 capsular contractures among 27 women (54 breasts) receiving antibiotic irrigation and 2 capsular contractures among 28 women (56 breasts) treated with saline irrigation. The difference in risk for both studies, whether considered individually or combined, is nonsignificant [1]. How is this comparison affected when the data from Burkhardt et al. [4] are added? Burkhardt et al. [4] reported 28 capsular contractures among 144 breasts that received some combination of antibiotics and steroids (19%) versus 15 capsular contractures among 37 control breasts (41%). Pooling the data from the 3 studies, [2-4] a total of 42 capsular contractures were reported for breasts treated with antibiotic solutions among 604 breasts (7.0%). By comparison, 34 capsular contractures were reported among 515 breasts that received either saline irrigation or no irrigation (6.6%). Control breasts actually experienced a slightly lower percentage of capsular contractures overall. A Chisquare test [5] produces a nonsignificant p value of 0.82 for this comparison (Table 1). Awad et al. [1] also compared antibiotic irrigation with no irrigation [1]. Only two studies included such a comparison [7, 8]. In one study, by Blount et al. [7], women receiving antibiotic irrigation experienced a 0.4% rate of capsular contracture versus 3.9% for women treated with no irrigation, a 10-fold difference. However, Blount et al. [7] found that there was no significant difference in capsular contracture rates on multivariate analysis (i.e., after correction for other variables impacting the capsular contracture rate). Giordano et al. [8] reported an advantage for antibiotic irrigation plus povidone-iodine solution, but the sample size (n = 330) was insufficient for a reliable conclusion [9]. The value of antimicrobial pocket irrigation has been challenged [10]. Bottles of Betadine (10% povidoneiodine) are labeled ‘‘Topical Bactericide.’’ The warnings, ‘‘Antiseptic Non-Sterile Solution’’ and ‘‘For External Use Only,’’ appear on the bottles [11]. Adams and Calobrace [12] recently suggested that the inside of the bottle is & Eric Swanson [email protected]