A Predictive Model for Determining Permanent Implant Size During 2-Stage Implant Breast Reconstruction

Two-stage tissue expander (TE)/permanent implant (PI) breast reconstruction remains the most commonly performed technique in breast reconstruction. Predictions for the PI size preoperatively impact on the number and range of implants made available at TE exchange. This study aims to identify critical preoperative variables and create a predictive model for PI size.

Patients who underwent 2-stage implant breast reconstruction from 2011 to 2017 were included in the study. Linear and multivariate regression analyses were used to identify significant preoperative variables for PI volume.

During the study period, 826 patients underwent 2-stage TE/PI breast reconstruction. Complete records were available for 226 breasts. Initial TE fill ranged from 0% to 102% with a mean final fill of 100.6% of TE volume. The majority of PIs were smooth round (98.2%), silicone (90%) implants. In a multivariate analysis, significant variables for predicting PI size were TE final fill volume (P < 0.0001), TE size (P = 0.03), and a history of preoperative radiation (P = 0.001). Relationships between these 3 variables were utilized to form a predictive model with a regression coefficient of R² = 0.914.

Significant variables for predicting PI volume were TE final fill volume, TE size, and a history of preoperative radiation. The ability to more accurately predict the PI volume can improve surgical planning, reduce consignment inventory, and simplify operating room workflow.