Sasaki Yasuhito, Ochiai Nobuyasu, Hashimoto Eiko, Sasaki Yu, Yamaguchi Takeshi, Kijima Takehiro, Akimoto Koji, Ohtori Seiji, Takahashi Kazuhisa
Department of Orthopedic Surgery, Graduate School of Medicine, Chiba University, Japan.
Department of Orthopedic Surgery, Graduate School of Medicine, Chiba University, Japan.
J Orthop Sci. 2018 Mar;23(2):414-419. doi: 10.1016/j.jos.2017.12.005. Epub 2018 Jan 12.
Rotator cuff tears are believed to coexist with cervical spine lesions. In cases of preexisting neuropathy, such as cervical spine lesions, fatty degeneration has likely already occurred due to the neuropathy. In these cases, rotator cuff tear is thought to occur easily because of preexisting extensive fatty degeneration and degeneration of the tendons due to neuropathy. This study aimed to evaluate the effects of paralysis due to neuropathy proximal to the suprascapular nerve on the supraspinatus and infraspinatus tendons using a rat model of brachial plexus paralysis.
This study included fifteen, 8-week-old Sprague-Dawley rats. The left shoulder was included in the paralysis group and the contralateral shoulder constituted the sham group. Biomechanical testing (evaluated maximum tear force, maximum displacement and Young's modulus) (n = 10) and histological analyses (n = 5) (using the Bonar scale) were performed at 12 weeks postoperatively to confirm the degeneration of the tendon.
The mean maximum tear force was significantly lower in the paralysis group than in the sham group (P = 0.008), indicating that rotator cuff tears occurred with a lower force in the paralysis group. Additionally, the average Young's modulus was significantly greater in the paralysis group than in the sham group (P = 0.003), indicating that the rotator cuff muscle became hard and inflexible in the paralysis group. The Bonar scales of the histological analyses were significantly higher in the paralysis group (total score = 7.04 ± 0.61) than the sham group (total score = 0) (p < 0.0001).
If neuropathy of proximal to the suprascapular nerve, such as cervical spine or brachial plexus lesion, exists, weakness and degeneration of the rotator cuff tendon and stiffness of the rotator cuff muscle develop. Neuropathy is likely a cause of rotator cuff tears.
肩袖撕裂被认为与颈椎病变并存。在已有神经病变的情况下，如颈椎病变，由于神经病变，脂肪变性可能已经发生。在这些病例中，由于先前存在广泛的脂肪变性和神经病变导致的肌腱变性，肩袖撕裂被认为很容易发生。本研究旨在使用臂丛神经麻痹大鼠模型评估肩胛上神经近端神经病变导致的麻痹对冈上肌和冈下肌腱的影响。
本研究纳入了15只8周龄的Sprague-Dawley大鼠。左侧肩部纳入麻痹组，对侧肩部作为假手术组。术后12周进行生物力学测试（评估最大撕裂力、最大位移和杨氏模量）（n = 10）和组织学分析（n = 5）（使用博纳尔量表），以确认肌腱的变性。
麻痹组的平均最大撕裂力显著低于假手术组（P = 0.008），表明麻痹组肩袖撕裂所需的力较小。此外，麻痹组的平均杨氏模量显著高于假手术组（P = 0.003），表明麻痹组肩袖肌肉变硬且缺乏弹性。组织学分析的博纳尔量表评分在麻痹组（总分 = 7.04 ± 0.61）显著高于假手术组（总分 = 0）（p < 0.0001）。
如果存在肩胛上神经近端的神经病变，如颈椎或臂丛神经损伤，肩袖肌腱会出现无力和变性，肩袖肌肉会出现僵硬。神经病变可能是肩袖撕裂的一个原因。
