Pataky Joshua, Graves Camille L, Heitzenrater Jared, Caru Maxime, Vidt Meghan E
Department of Biomedical Engineering, Pennsylvania State University, University Park, PA, USA.
Department of Public Health Sciences, Penn State College of Medicine, Hershey, PA, USA.
Support Care Cancer. 2025 Apr 16;33(5):390. doi: 10.1007/s00520-025-09454-1.
Mastectomy and reconstruction are treatment components for many breast cancer patients, resulting in long-term shoulder dysfunction. Computational models specific to surgical approach would enable study of underlying mechanisms of shoulder dysfunction, but none exist. Our objectives were as follows: (1) develop and validate models representing lumpectomy, implant-based, and autologous flap-based reconstruction; and (2) determine how muscle contribution to hand acceleration during functional movements differs across models.
The upper limb model in OpenSim was scaled to force-generating properties and anthropometry of adult females. A 405-cc wrapping surface was placed beneath the pectoralis major muscle path representing subpectoral implant placement. For model validation, shoulder moment was predicted in five postures, with an external load applied equal to mean strength measured from a breast cancer patient cohort. Induced acceleration analysis was used to identify primary muscle contributors to hand acceleration during functional movements.
Following model development, pectoralis major moment arm was reduced in the implant model compared to lumpectomy and flap models. Predicted shoulder moments fell within 1 standard deviation of experimental moments (i.e., external rotation: lumpectomy model, 15.1Nm; implant model, 14.1Nm; flap model, 17.5Nm; experimentally measured, 14.1Nm ± 5.4Nm; 13.0Nm ± 3.6Nm; 15.5Nm ± 5.3Nm, respectively), except horizontal abduction (all groups) and elevation (lumpectomy group), providing validation. Large shoulder muscles, including deltoid, infraspinatus, and subscapularis, were the largest contributors to hand acceleration. Pectoralis major was also identified, possibly relating to post-surgical functional deficits.
This work identified muscle moment arm changes for implant-based reconstruction. These models can be used to predict functional outcomes of differing reconstruction surgeries.
乳房切除术和乳房重建是许多乳腺癌患者的治疗组成部分，会导致长期的肩部功能障碍。针对手术方式的计算模型能够研究肩部功能障碍的潜在机制，但目前尚无此类模型。我们的目标如下：（1）开发并验证代表乳房肿瘤切除术、植入物重建和自体皮瓣重建的模型；（2）确定在功能运动过程中，不同模型的肌肉对手部加速的贡献有何差异。
将OpenSim中的上肢模型按成年女性的力产生特性和人体测量学进行缩放。在胸大肌路径下方放置一个405立方厘米的包裹表面，代表胸肌下植入物的放置。为进行模型验证，预测了五个姿势下的肩部力矩，并施加等于从一组乳腺癌患者测量的平均力量的外部负荷。采用诱导加速度分析来确定功能运动过程中对手部加速起主要作用的肌肉。
模型开发后，与乳房肿瘤切除术和皮瓣模型相比，植入物模型中胸大肌的力臂减小。预测的肩部力矩落在实验力矩的1个标准差范围内（即，外旋：乳房肿瘤切除术模型，15.1牛米；植入物模型，14.1牛米；皮瓣模型，17.5牛米；实验测量值分别为14.1牛米±5.4牛米、13.0牛米±3.6牛米、15.5牛米±5.3牛米），水平外展（所有组）和抬高（乳房肿瘤切除组）除外，从而验证了模型。包括三角肌、冈下肌和肩胛下肌在内的肩部大肌肉是手部加速的最大贡献者。胸大肌也被确定为贡献者，这可能与术后功能缺陷有关。
本研究确定了基于植入物重建的肌肉力臂变化。这些模型可用于预测不同重建手术的功能结果。
