Finding the Right Fill: The Ideal Tissue Expander Fill in Immediate Prepectoral Breast Reconstruction

Although many factors in prepectoral breast reconstruction such as mastectomy weight and flap quality are out of the plastic surgeon's control, some elements such as intraoperative tissue expander (TE) fill can be optimized. This study assesses the impact of intraoperative TE fill on postoperative complications in prepectoral breast reconstruction and posits the optimal fill.

All consecutive, prepectoral TE reconstructions performed between March 2017 and December 2022 at a single center were reviewed. A "fill ratio" or ratio of intraoperative TE fill to mastectomy weight (TEF/MW) was constructed to quantify deadspace in the breast pocket, with values closer to 1 signifying less deadspace. Major complications include those requiring readmission or reoperation and minor complications include those that could be treated as an outpatient. A P < 0.05 was considered statistically significant.

A total of 200 patients (318 breasts) with average follow-up of 22 months were included. Patients were, on average, 53 years old, were nonsmoker (98%), were nondiabetic (91%), and had a body mass index of 26 kg/m2. Only immediate reconstructions were included and were performed following prophylactic mastectomies in 34% and therapeutic mastectomies in 66% of cases. Seventy-six (24%) breasts were radiated, and 93 (47%) patients received chemotherapy. Mean mastectomy weight was 546 g, median intraoperative TE fill was 175 ± 250 cc, and median final TE fill was 390 ± 220 cc.Major complications occurred in 64 (20%) breasts and were associated with less deadspace (0.49 vs 0.36, P < 0.05). In multivariable models, a higher fill ratio was associated with 2.4 times higher odds of major complications (95% CI, 1.2-4.7; P = 0.01). Optimal intraoperative TE fill for avoiding major complications was 80 cc, and optimal fill ratio was 0.09.Explantation occurred in 44 (14%) breasts and was associated with less deadspace (0.51 vs 0.35, P < 0.05); the optimal fill for avoiding explantation was 80 cc, and optimal ratio was 0.12.

Higher intraoperative TE fill and less deadspace were associated with postoperative complications. Filling a TE to 80 cc or approximately a tenth of mastectomy weight may reduce complications.