School of Kinesiology, University of Michigan, Ann Arbor, MI, USA.
Section of Plastic Surgery, University of Michigan, Ann Arbor, MI, USA.
J Biomech. 2021 May 7;120:110348. doi: 10.1016/j.jbiomech.2021.110348. Epub 2021 Mar 1.
Immediate two-stage subpectoral implant breast reconstruction after mastectomy requires the surgical disinsertion of the sternocostal fiber region of the pectoralis major (PM). The disinsertion of the PM would need increased contributions from intact shoulder musculature to generate shoulder torques. This study aimed to identify neuromuscular compensation strategies adopted by subpectoral implant breast reconstruction patients using novel muscle synergy analyses. Fourteen patients treated bilaterally with subpectoral implant breast reconstruction (>2.5 years post-reconstruction) were compared to ten healthy controls. Surface electromyography was obtained from sixteen shoulder muscles as participants generated eight three-dimensional (3D) shoulder torques in five two-dimensional arm postures bilaterally. Non-negative matrix factorization revealed the muscle synergies utilized by each experimental group on the dominant and non-dominant limbs, and the normalized similarity index assessed group differences in overall synergy structure. Bilateral subpectoral implant patients exhibited similar shoulder strength to healthy controls on the dominant and non-dominant arms. Our results suggest that 3D shoulder torque is driven by three shoulder muscle synergies in both healthy participants and subpectoral implant patients. Two out of three synergies were more similar than is expected by chance between the groups on the non-dominant arm, whereas only one synergy is more similar than is expected by chance on the dominant arm. While bilateral shoulder strength is maintained following bilateral subpectoral implant breast reconstruction, a closer analysis of the muscle synergy patterns underlying 3D shoulder torque generation reveals that subpectoral implant patients adopt compensatory neuromuscular strategies only with the dominant arm.
即刻双阶段胸肌下假体乳房重建术需要外科分离胸大肌（PM）的胸骨肋纤维区域。PM 的分离需要完整的肩部肌肉做出更大的贡献，以产生肩部扭矩。本研究旨在使用新的肌肉协同分析方法，确定胸肌下假体乳房重建患者采用的神经肌肉补偿策略。将 14 名双侧接受胸肌下假体乳房重建的患者（重建后>2.5 年）与 10 名健康对照者进行比较。参与者在双侧进行了五个二维臂位的八种三维（3D）肩部扭矩生成，同时从 16 个肩部肌肉中获得了表面肌电图。非负矩阵分解揭示了每个实验组在优势和非优势肢体上使用的肌肉协同，归一化相似性指数评估了总体协同结构的组间差异。双侧胸肌下假体患者在优势和非优势手臂上的肩部力量与健康对照组相似。我们的结果表明，3D 肩部扭矩由健康参与者和胸肌下假体患者的三个肩部肌肉协同驱动。在非优势手臂上，三个协同中有两个比预期的更相似，而在优势手臂上只有一个协同比预期的更相似。虽然双侧胸肌下假体乳房重建后双侧肩部力量得以维持，但对 3D 肩部扭矩生成的肌肉协同模式进行更深入的分析表明，胸肌下假体患者仅在优势手臂上采用代偿性神经肌肉策略。
