School of Kinesiology, University of Michigan, Ann Arbor, Michigan, United States.
College of Applied Health Sciences, University of Illinois, Urbana-Champaign, Illinois, United States.
J Neurophysiol. 2023 Apr 1;129(4):914-926. doi: 10.1152/jn.00081.2022. Epub 2023 Mar 22.
Muscle stiffness is altered following postmastectomy breast reconstruction and breast cancer treatment. The exact mechanisms underlying these alterations are unknown; however, muscle stretch reflexes may play a role. This work examined short- (SLR) and long-latency (LLR) shoulder muscle stretch reflexes in breast cancer survivors. Forty-nine patients who had undergone postmastectomy breast reconstruction, 17 who had undergone chemoradiation, and 18 healthy, age-matched controls were enrolled. Muscle activity was recorded from the clavicular and sternocostal regions of the pectoralis major and anterior, middle, and posterior deltoids during vertical ab/adduction or horizontal flex/extension perturbations while participants maintained minimal torques. SLR and LLR were quantified for each muscle. Our major finding was that following postmastectomy breast reconstruction, SLR and LLR are impaired in the clavicular region of the pectoralis major. Individuals who had chemoradiation had impaired stretch reflexes in the clavicular and sternocostal region of the pectoralis major, anterior, middle, and posterior deltoid. These findings indicate that breast cancer treatments alter the regulation of shoulder muscle stretch reflexes and may be associated with surgical or nonsurgical damage to the pectoral fascia, muscle spindles, and/or sensory Ia afferents. Shoulder muscle stretch reflexes may be impacted following postmastectomy breast reconstruction and chemoradiation. Here, we examined short- and long-latency shoulder muscle stretch reflexes in two experiments following common breast reconstruction procedures and chemoradiation. We show impairments in pectoralis major stretch reflexes following postmastectomy breast reconstruction and pectoralis major and deltoid muscle stretch reflexes following chemoradiation. These findings indicate that breast cancer treatments alter the regulation of shoulder muscle stretch reflexes.
肌肉僵硬在乳房再造术后和乳腺癌治疗后发生改变。这些改变的确切机制尚不清楚；然而，肌肉拉伸反射可能起作用。这项工作检查了乳腺癌幸存者的短（SLR）和长潜伏期（LLR）肩部肌肉拉伸反射。招募了 49 名接受过乳房再造术后的患者，17 名接受过放化疗的患者和 18 名年龄匹配的健康对照组。参与者保持最小扭矩的同时，在垂直的上下或水平的前后屈伸干扰下，从胸大肌锁骨和胸骨区域记录肌肉活动，在前、中、后三角肌。对每个肌肉的 SLR 和 LLR 进行量化。我们的主要发现是，乳房再造术后，胸大肌锁骨区域的 SLR 和 LLR 受损。接受过放化疗的患者胸大肌锁骨和胸骨区域、前、中、后三角肌的拉伸反射受损。这些发现表明，乳腺癌治疗改变了肩部肌肉拉伸反射的调节，可能与胸筋膜、肌梭和/或感觉 Ia 传入神经的手术或非手术损伤有关。乳房再造术后和放化疗后可能会影响肩部肌肉拉伸反射。在这里，我们在两个实验中检查了两种常见的乳房重建手术后和放化疗后的短潜伏期和长潜伏期肩部肌肉拉伸反射。我们显示乳房再造术后胸大肌拉伸反射受损，以及放化疗后胸大肌和三角肌拉伸反射受损。这些发现表明，乳腺癌治疗改变了肩部肌肉拉伸反射的调节。
