The Influence of Functional Shoulder Biomechanics as a Mediator of Patient Reported Outcomes Following Mastectomy and Breast Reconstruction.
- 2020
BACKGROUND: Post-mastectomy breast reconstruction techniques differentially influence patient-reported physical and psychosocial well-being. Objective measures of shoulder biomechanics, which are uniquely influenced by reconstruction technique, may provide insight into the influence of reconstruction technique on patient-reported outcomes. CONCLUSIONS: In the current cohort, LD+subpectoral implant breast reconstructions significantly reduced shoulder strength and stiffness when compared to the other techniques. Additionally, objective measures of shoulder biomechanics were predictive of patient-reported physical and psychosocial well-being. Our results emphasize the need for improved peri-operative screening for shoulder functional deficits in patients undergoing breast reconstruction. METHODS: Robot-assisted measures of shoulder strength and stiffness, and patient-reported outcomes surveys (PROMIS-UE, SPADI, QuickDASH, SF12-PCS, SF12-MCS) were obtained from 46 women who had previously undergone mastectomy and a combined latissimus dorsi flap + subpectoral implant (LD + subpectoral implant), subpectoral implant, or DIEP flap breast reconstruction. Mediation analyses examined the role of functional shoulder biomechanics as a mediator between reconstruction technique and patient-reported outcomes. RESULTS: Reconstruction technique uniquely affected shoulder biomechanics, with LD+subpectoral implant patients exhibiting reduced shoulder strength and stiffness compared to subpectoral implant and DIEP flap patients. Increasing external rotation strength was predictive of increasing PROMIS-UE score (p=0.04), indicating improved upper extremity function. Increasing shoulder stiffness while at rest was predictive of increasing QuickDASH score (p=0.03), indicating worsened upper extremity function, while increasing stiffness at rest and during contraction was indicative of decreasing SF12-MCS score (all p<=0.02), indicating worsened psychosocial well-being. Reconstruction technique did not predict survey scores of function directly, or when mediated by functional shoulder biomechanics.