A large number of clinical studies have reported that the different materials used in
breast implants were a possible cause of the different incidence rates of capsular
contracture observed in patients after implantation. However, this theory lacks comprehensive support from evidence-based medicine, and considerable controversy remains.
OBJECTIVES: We conducted a comprehensive search of literature databases, including PubMed and EMBASE, for clinical reports on the incidence of capsular
contracture after the implantation of breast
prostheses. We performed a cumulative meta-analysis on the incidence of capsular
contracture in order from small to large sample sizes and conducted subgroup analyses according to the prosthetic material used, the implant pocket placement, the incision type and the duration of follow-up. Relative risks (RR) and 95% confidence intervals (CI) were used as the final pooled statistics.
RESULTS: This meta-analysis included 16 randomized controlled trials (RCTs) and two retrospective studies. The cumulative comparison of textured and smooth
breast implants showed statistical significance at 2.13 (95% CI, 1.18-3.86) when the fourth study was entered into the analysis. With the inclusion of more reports, the final results indicated that smooth
breast implants were more likely to be associated with capsular
contracture, with statistical significance at 3.10 (95% CI, 2.23-4.33). In the subgroup analyses, the subgroups based on implant materials included the
silicone implant group and the saline implant group, with significant pooled statistical levels of 4.05 (95% CI, 1.97-8.31) and 3.12 (95% CI, 2.19-4.42), respectively. According to implant pocket placement, a subglandular group and a submuscular group were included in the analyses, and only the subglandular group had a statistically significant pooled result of 3.59 (95% CI, 2.43-5.30). Four subgroups were included in the analyses according to incision type: the inframammary incision group, the periareolar incision group, the transaxillary incision group and the
mastectomy incision group. Among these groups, only the pooled results of the inframammary and
mastectomy incision groups were statistically significant, at 2.82 (95% CI, 1.30-6.11) and 2.30 (95% CI, 1.17-4.50), respectively. Three follow-up duration subgroups were included in the analyses: the one-year group, the two- to three-year group and the ≥ five-year group. These subgroups had statistically significant results of 4.67 (95% CI, 2.35-9.28), 3.42 (95% CI, 2.26-5.16) and 2.71 (95% CI, 1.64-4.49), respectively.
CONCLUSION: In
mammaplasty, the use of textured implants reduces the incidence of postoperative capsular
contracture. Differences in implant pocket placement and incision type are also likely to affect the incidence of capsular
contracture; however, this conclusion awaits further study.