“Validating a Digital Recovery Tool for Autologous Breast Reconstruction”

Abstract Background Recent research aims to leverage technology to further understand surgical recovery by utilising continuous data. Traditional metrics of readmission, flap failure, and patient-reported outcome measures are limited by poor accuracy and subjectivity. This study aimed to validate smartphone-derived physical activity data to objectively measure and analyse trends in recovery following deep inferior epigastric perforator (DIEP) flap breast reconstruction. Methods A single-centre, retrospective study was conducted. Eligible participants who underwent DIEP reconstruction downloaded a bespoke smartphone application, which retrieved data from 1 month pre-operatively to 12 months post-operatively. Physical activity was compared and validated against wearable activity monitor data from a previous study. Temporal trends were visualised using mean daily activity values over predefined intervals. Univariable linear regression assessed associations between clinical variables and short-term recovery. Results Forty-one patients were included in the study. Wearable activity monitor and smartphone datasets (n=10) showed a positive correlation (0.6379, p=0.0105) demonstrating concurrent validity. Analysis of recovery in DIEP patients (n=34) demonstrated a median return to baseline activity at 27 days (IQR 12). Physical activity decreased after DIEP, with mean daily activity dropping to 18% of baseline in the first 2 weeks (S.D=11%, p<0.0001) before improving to 107% at 8-12 weeks (S.D=78%, p=0.9999). Immediate post-operative reconstruction (p=0.046) and lack of post-operative complications (p=0.0063), were short-term predictors of physical activity. Conclusion This study validates smartphone physical activity as an objective recovery metric in DIEP reconstruction. Future applications include developing recovery prediction models for shared decision-making, implementing peri-operative interventions and post-operative monitoring.