Implant Size Versus Mastectomy Weight in Breast Reconstruction: Does Matching Matter?

During nipple-sparing mastectomy with direct-to-implant based breast reconstruction, if the size of the chosen implant is smaller than the mastectomy specimen, a volumetric mismatch occurs creating dead space. This study evaluates the effect of volumetric mismatch between chosen implant size and mastectomy weight on postoperative complications after breast reconstruction.

A multicenter retrospective cohort study was conducted on patients undergoing nipple-sparing mastectomy with direct-to-implant based breast reconstruction. The effect of volumetric mismatch [mastectomy weight (g) - implant size (mL)] on postoperative complications were evaluated using receiver operating characteristic analysis and multivariable regression analyses.

A total of 1617 breast reconstructions were performed in 1031 patients. The mean mastectomy weight was 442.6 g (±219.1), the mean implant size was 403.2 mL (±152.0) and the mean volumetric mismatch was 37.1 (±108.2). The mean follow-up was 25.3 months (±15.2). Total complication rate was 8.3%. A volumetric mismatch of ≥78 was associated with increased complications when controlled for mastectomy weight and implant size, with higher rates of any complication (14.6% vs 6.4%, P < 0.0001), explantation due to infection (2.9% vs 1.1%, P = 0.05), infection (4.5% vs 1.6%, P = 0.01), and seroma (6.9% vs 1.9%, P < 0.0001). On multivariable regression for any complication, volumetric mismatch [odds ratio 1.9 (95% CI 1.0-3.4) P = 0.043], smoking and age were significant predictors.

A greater mismatch between implant size and mastectomy weight was a significant predictor of postoperative complications, including explantation. Knowing this, surgeons may choose to match implant size more evenly to mastectomy weight, opt for skin sparing mastectomies or consider operative techniques to minimize dead space.