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Mastectomy Weight Threshold For Complications In Prepectoral Vs. Subpectoral Tissue Expander Breast Reconstruction
Colby J. Hyland, MD, Smrithi Dhananjaya, BS, Goutam Gadiraju, BS, Lingwei Xiang, MPH, Tanujit Dey, PhD, Yoon S. Chun, MD.
Mass General Brigham, Boston, MA, USA.
PURPOSE: In two-stage implant-based breast reconstruction, prepectoral versus subpectoral tissue expander (TE) placement remains debated. Clinical thresholds that guide the choice of reconstructive plane are needed. This study evaluated whether mastectomy specimen weight influences complication risk by anatomic plane of TE placement.
METHODS: All consecutive women undergoing therapeutic or prophylactic mastectomy with immediate TE placement between 03/2024 - 02/2025 were included. Ninety-day postoperative complications (hematoma, infection, seroma, necrosis, dehiscence, reoperation, explant) were analyzed per breast. Associations between TE location and complications were assessed with multivariable logistic regression, adjusting for covariates. Spline models were applied to determine mastectomy specimen weight threshold at which complication risk differed between planes.
RESULTS: A total of 510 reconstructions in 309 patients were analyzed (334 [65.5%] prepectoral; 176 [34.5%] subpectoral). Demographics, comorbidities, chemotherapy, radiotherapy, and mastectomy type (skin- or nipple-sparing) were comparable. Overall complication rates were similar (26.9% prepectoral vs. 23.9% subpectoral,
p=0.52). Increasing mastectomy weight was independently associated with higher complication risk after controlling for BMI (
p=0.006). Beyond a mastectomy weight >880 gm, subpectoral placement demonstrated significantly lower complication rates than prepectoral placement (Figure 1).
CONCLUSION: While overall complication rates were similar between prepectoral and subpectoral TE placement, increasing mastectomy weight independently elevated complication risk. For patients with high mastectomy weights (>880 gm), subpectoral placement may offer a safer reconstructive strategy and should be considered in operative planning.
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