Can the Weight of an External Breast Prosthesis Influence Trunk Biomechanics during Functional Movement in Postmastectomy Women?

INTRODUCTION: Recent papers indicate that one-side mastectomy can produce deleterious effects on the posture and musculoskeletal system. This study was conducted to better understand the underlying mechanisms involved in trunk motion in external prosthesis users. OBJECTIVE: The aim was to evaluate the changes in surface electromyographic (SEMG) activity of the erector spinae muscles (ES) in postmastectomy women with and without breast prostheses during functional body movement tests. METHODS: In 51 one-side postmastectomy women the SEMG muscle activity of bilateral ES was measured during symmetrical and asymmetrical dynamic activities in a counterbalanced manner with different weights of the breast prosthesis. Range-of-motion measurements were taken for forward bending, backward bending, lateral bending, and rotation. RESULTS: The mean level of the ES activity in the lumbar region was not affected by the weight of the external breast prosthesis during most of the functional body tests (P > 0.05). The activity of ES during functional body tests with and without different external breast prostheses did not differ between the two sides of the trunk (mastectomy and nonmastectomy) for most of the movement tests (P > 0.05). CONCLUSION: The lumbar ES activity during functional tests is not associated with the weight of the external breast prosthesis in postmastectomy women.