Contribution of denervated muscle to contractures after neonatal brachial plexus injury: Not just muscle fibrosis

Nikolaou, Sia; Hu, Liangjun; Tuttle, Lori J.; Weekley, Holly; Wylie, Christopher; Lieber, Richard L.; Cornwall, Roger

doi:10.1002/mus.23927

Cited by 51 publications

(46 citation statements)

References 40 publications

(45 reference statements)

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“…Some studies reported muscular fibrosis after central or peripheral nervous system disorders [2,35] and are consistent with our results. In our animal study, muscular fibrosis after spinal cord injury was not improved by any treatments, but stretching after heat improved the muscular factor of contractures.…”

Section: Discussionsupporting

confidence: 93%

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Stretching After Heat But Not After Cold Decreases Contractures After Spinal Cord Injury in Rats

Iwasawa

Nomura

Sakitani

et al. 2016

Clinical Orthopaedics &Amp; Related Research

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Background Contractures are a prevalent and potentially severe complication in patients with neurologic disorders. Although heat, cold, and stretching are commonly used for treatment of contractures and/or spasticity (the cause of many contractures), the sequential effects of these modalities remain unclear. Questions/purposes Using an established rat model with spinal cord injury with knee flexion contracture, we sought to determine what combination of heat or cold before stretching is the most effective for treatment of contractures derived from spastic paralyses and investigated which treatment leads to the best (1) improvement in the loss of ROM; (2) restoration of deterioration in the muscular and articular factors responsible for contractures; and (3) amelioration of histopathologic features such as muscular fibrosis in biceps femoris and shortening of the joint capsule. Methods Forty-two adolescent male Wistar rats were used. After spasticity developed at 2 weeks postinjury, each animal with spinal cord injury underwent the treatment protocol daily for 1 week. Knee extension ROM was measured with a goniometer by two examiners blinded to each other's scores. The muscular and articular factors contributing to contractures were calculated by measuring ROM before and after the myotomies. We quantitatively measured the muscular fibrosis and the synovial intima length, and observed the distribution of collagen of skeletal muscle. The results were confirmed by a blinded observer. Results The ROM of heat alone (34°± 1°) and cold alone (34°± 2°) rats were not different with the numbers available from that of rats with spinal cord injury (35°± 2°) (p = 0.92 and 0.89, respectively). Stretching after heat (24°± 1°) was more effective than stretching alone (27°± 3°) at increasing ROM (p \ 0.001). Contrastingly, there was no difference between stretching after cold (25°± 1°) and stretching alone (p = 0.352). Stretching after heat was the most effective for percentage improvement of muscular (29%) and articular (50%) factors of contractures. Although quantification of muscular fibrosis in the rats with spinal cord injury (11% ± 1%) was higher than that of controls (9% ± 0.4%) (p = 0.01), no difference was found between spinal cord injury and each treatment protocol. The total synovial intima length of rats with spinal cord injury (5.9 ± 0.2 mm) became shorter than those of the controls (7.6 ± 0.2 mm) (p \ 0.001), and those of stretching alone (6.9 ± 0.4 mm), stretching after heat (7.1 ± 0.3 mm), and stretching after cold (6.7 ± 0.4 mm)

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Section: Discussionsupporting

confidence: 93%

“…We evaluated muscular fibrosis, which contributes to poor muscle extensibility in muscular contracture [2,35], by a slight modification of the method according to Hadi et al [13]. Four samples of biceps femoris were randomly selected from each group.…”

Section: Quantification Of Fibrosis In Muscle Tissuementioning

confidence: 99%

Stretching After Heat But Not After Cold Decreases Contractures After Spinal Cord Injury in Rats

Iwasawa

Nomura

Sakitani

et al. 2016

Clinical Orthopaedics &Amp; Related Research

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“…Nikolaou has shown that functional shortening of denervated muscle plays a primary role in contracture pathogenesis [32]. However, the mechanism of contracture development in denervated muscle remains unanswered [33,34].…”

Section: Natural Historymentioning

confidence: 99%

The natural history and management of brachial plexus birth palsy

Buterbaugh

Shah

2016

Curr Rev Musculoskelet Med

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Brachial plexus birth palsy (BPBP) is an upper extremity paralysis that occurs due to traction injury of the brachial plexus during childbirth. Approximately 20 % of children with brachial plexus birth palsy will have residual neurologic deficits. These permanent and significant impacts on upper limb function continue to spur interest in optimizing the management of a problem with a highly variable natural history. BPBP is generally diagnosed on clinical examination and does not typically require cross-sectional imaging. Physical examination is also the best modality to determine candidates for microsurgical reconstruction of the brachial plexus. The key finding on physical examination that determines need for microsurgery is recovery of antigravity elbow flexion by 3-6 months of age. When indicated, both microsurgery and secondary shoulder and elbow procedures are effective and can substantially improve functional outcomes. These procedures include nerve transfers and nerve grafting in infants and secondary procedures in children, such as botulinum toxin injection, shoulder tendon transfers, and humeral derotational osteotomy.

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“…In fact, shoulder contracture appeared only after the first week of the neural injury. Subscapularis thickness and weight decrease were also substantially higher than those in the imbalance model with a severe subscapularis muscle fiber atrophy . In our model of complete neurotmesis of both superior and inferior subscapularis nerves, reinnervation was impossible.…”

Section: Discussionmentioning

confidence: 51%

“…Subscapularis thickness loss is a consistent MRI finding in patients with an internal rotation contracture and glenohumeral joint dysplasia . The pathogenesis of subscapularis changes seems to be multifactorial and derived from an alteration in muscle growth both in length and thickness, by either shoulder rotation imbalance, subscapularis denervation, or both …”

Section: Discussionmentioning

confidence: 93%

The role of subscapularis muscle denervation in the pathogenesis of shoulder internal rotation contracture after neonatal brachial plexus palsy: A study in a rat model

et al. 2014

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We assessed the role of subscapularis muscle denervation in the development of shoulder internal rotation contracture in neonatal brachial plexus injury. Seventeen newborn rats underwent selective denervation of the subscapular muscle. The rats were evaluated at weekly intervals to measure passive shoulder external rotation. After 4 weeks, the animals were euthanized. The subscapularis thickness was measured using 7.2T MRI axial images. The subscapularis muscle was then studied grossly, and its mass was registered. The fiber area and the area of fibrosis were measured using collagen-I inmunostained muscle sections. Significant progressive decrease in passive shoulder external rotation was noted with a mean loss of 58° at four weeks. A significant decrease in thickness and mass of the subscapularis muscles in the involved shoulders was also found with a mean loss of 69%. Subscapularis muscle fiber size decreased significantly, while the area of fibrosis remained unchanged. Our study shows that subscapularis denervation, per se, could explain shoulder contracture after neonatal brachial plexus injury, though its relevance compared to other pathogenic factors needs further investigation.

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Contribution of denervated muscle to contractures after neonatal brachial plexus injury: Not just muscle fibrosis

Abstract: Contractures after NBPI cannot be explained solely by muscle fibrosis, arguing for investigation of alternate pathophysiologic targets for contracture prevention and treatment.

Cited by 51 publications

References 40 publications

Stretching After Heat But Not After Cold Decreases Contractures After Spinal Cord Injury in Rats

Stretching After Heat But Not After Cold Decreases Contractures After Spinal Cord Injury in Rats

The natural history and management of brachial plexus birth palsy

The role of subscapularis muscle denervation in the pathogenesis of shoulder internal rotation contracture after neonatal brachial plexus palsy: A study in a rat model

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