Preoperative Lower Back Pain is a Risk Factor for Worse Physical Well-Being of the Abdomen After Breast Reconstruction.

Abdominally based free flap breast reconstruction offers excellent long-term outcomes, but donor-site morbidity remains a concern. Lower back pain is a prevalent musculoskeletal condition that may impair core stability and abdominal donor-site recovery after surgery. This study evaluated the association between a preexisting diagnosis of lower back pain and long-term physical well-being of the abdomen after surgery.We conducted a retrospective study of patients who underwent abdominally based free flap breast reconstruction between 2017 and 2024. Patients were categorized by the presence or absence of a preexisting diagnosis of lower back pain. The primary outcome was physical well-being of the abdomen, assessed using the BREAST-Q. Multivariable linear mixed-effects models evaluated the association between lower back pain and abdominal well-being.A total of 2,594 patients were included. Donor-site complications occurred in 15% of patients, including wound dehiscence (9.1%), surgical site infection (4.3%), palpable bulge (2.4%), seroma (2.2%), and hematoma (0.5%). Patients with preexisting lower back pain (n = 298, 11.5%) had significantly lower abdominal well-being scores compared with those without at 1 year (62 vs. 69; p < 0.001) and 5 years (65 vs. 76; p = 0.014). On multivariable analysis, lower back pain was independently associated with worse abdominal well-being (β = -5, 95% confidence interval [CI]: -8.9 to -0.97; p = 0.015), exceeding the minimal clinically important difference of ≥4.Preexisting lower back pain is associated with significantly worse long-term abdominal well-being after breast reconstruction. Future studies should investigate targeted interventions such as pre- and postoperative core rehabilitation protocols to improve outcomes in these high-risk patients.