Biomechanical changes in the low back following reduction mammaplasty surgery

OBJECTIVE: To give evidence of the mechanical consequences of reduction mammaplasty (RM) on the low back. DESIGN: A repeated-measures analysis was implemented to test the effect of RM on the external loads and angular velocity of the back during both static and dynamic lifting tasks. BACKGROUND: Patient follow-up surveys have documented a decrease in the frequency of low back pain following RM, but there is no quantitative data regarding biomechanical changes following surgery. METHODS: Patients were evaluated before and 4-8 weeks following RM. Flexion moment, compression and shear forces at L3-L4 were quantified for isometric flexion angles between 0 and 40 degrees. External loads and angular velocities of the back were studied during rapid dynamic lifting tasks. RESULTS: Isometric external flexion moments at L3-L4 decreased following RM. RM did not effect the applied flexion moment in the lumbar spine, but a trend suggested that RM resulted in increased lifting velocity. CONCLUSIONS: RM does act to reduce the loads on the lumbar spine during simple isometric tasks. During dynamic tasks, subjects may be able to lift faster without generating larger loads.