Effects of Mastectomy on Shoulder and Spinal Kinematics During Bilateral Upper-Limb Movement

Background. Shoulder movement impairment is a commonly reported consequence of surgery for breast cancer. Objective. The aim of this study was to determine whether shoulder girdle kinematics, including those of the scapula, spine, and upper limb, in women who have undergone a unilateral mastectomy for breast cancer are different from those demonstrated by an age-matched control group. Design. An observational study using 3-dimensional kinematic analysis was performed. Methods. Women who had a unilateral mastectomy on their dominant-arm side (n=29, mean [+/- SD] age=62.4 +/- 8.9 years) or nondominant-arm side (n=24, mean [+/- SD] age=59.8 +/- 9.9 years), as well as a control group of age-matched women without upper-limb, shoulder, or spinal problems (n=22, mean [+/- SD] age=58.1 +/- 11.5 years), were measured while performing bilateral arm movements in the sagittal, scapular, and coronal planes. All of the women were free of shoulder pain at the time of testing. Data were collected from the glenohumeral joint, the scapulothoracic articulation, and the spine (upper and lower thoracic and lumbar regions) using an electromagnetic tracking system. Results. Women following mastectomy displayed altered patterns of scapular rotation compared with controls in all planes of movement. In particular, the scapula on the mastectomy side rotated upward to a markedly greater extent than that on the nonmastectomy side, and women following mastectomy displayed greater scapular excursion than controls. Conclusions. The findings suggest that altered motor patterns of the scapula are associated with mastectomy on the same side. Whether these changes are harmful or not is unclear. Investigation of interventions designed to restore normal scapulohumeral relationships on the affected side following unilateral mastectomy for breast cancer is warranted.