Validating a digital recovery tool for autologous breast reconstruction.

[BACKGROUND] Recent research aims to leverage technology to further understand surgical recovery by using continuous data. Traditional metrics of readmission, flap failure, and patient-reported outcome measures are limited by poor accuracy and subjectivity. We aimed to validate smartphone-derived physical activity data to objectively measure and analyze trends in recovery following deep inferior epigastric perforator (DIEP) flap breast reconstruction.

[METHODS] A single-center, retrospective study was conducted. Eligible participants who underwent DIEP reconstruction downloaded a bespoke smartphone application, which retrieved data from 1 month preoperatively to 12 months postoperatively. Physical activity was compared and validated against wearable activity monitor data from a previous study. Temporal trends were visualized 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 days). Physical activity decreased after DIEP, with mean daily activity dropping to 18% of baseline in the first 2 weeks (SD=11%, p<0.0001) before improving to 107% at 8-12 weeks (SD=78%, p=0.9999). Immediate postoperative reconstruction (p=0.046) and lack of postoperative 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 perioperative interventions, and postoperative monitoring.