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 °. 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.