Nerve dysfunction leads to muscle morphological abnormalities in chronic inflammatory demyelinating polyneuropathy assessed by MRI

Neuropathic features of chronic inflammatory demyelinating polyneuropathy (CIDP) have been well documented, however very little is known about the implication of this neuropathy on skeletal muscle, and whether nerve lesions in CIDP lead to uniform disruptions in skeletal muscles. In this study, we assessed the triceps surae complex, using magnetic resonance imaging (MRI) in a group (n = 10) of CIDP patients compared with a healthy age-matched control group (n = 9). MRI (T1 and T2) of the leg musculature as well as plantar flexion strength measurements were obtained from both groups. CIDP patients compared with controls had ∼28% lower plantar flexion strength and ∼19% less total muscle volume (T1) of the triceps surae. When strength was normalized to fat corrected triceps surae volume CIDP patients were ∼30% weaker than controls. Relaxation times from the T2 scans were significantly longer in CIDP with the soleus, medial head of gastrocnemius and lateral head of gastrocnemius showing ∼37%, ∼38% and ∼26% longer relaxation times, respectively. CIDP patients were significantly weaker compared to controls and despite normalizing strength to total triceps surae contractile tissue volume this difference remained. CIDP patients had significantly longer T2 times, reflecting increased noncontractile tissue infiltration. These results indicate reduced muscle quantity and quality as a result of alterations in axonal function. Furthermore, when present study results are considered together with a prior report on the anterior compartment (Gilmore et al. 2016, Muscle Nerve 3:413–420), it is clear that both anterior and posterior leg compartments are affected similarly in CIDP despite different terminal nerve innervation and functional properties. Clin. Anat. 32:77–84, 2019. © 2019 Wiley Periodicals, Inc.     

Achilles Tendon Lengthening for Equinus Foot with Miyoshi Myopathy: A Case Report

A 17-year-old male presented with reduced muscle strength in both lower limbs and demonstrated equinus foot (ankle equinus) in the right lower limb. Using dysferlin immunostaining, the patient was diagnosed with Miyoshi myopathy by the neurologist. Achilles tendon lengthening was performed, and a plantigrade foot without ankle equinus was achieved.     

C5和C6水平脊髓损伤的四肢瘫患者在伸肘活动中上肢和躯干的运动学分析

目的 分析C5，和C6水平脊髓损伤（SCI）的四肢瘫患者在与伸肘有关的日常生活活动中上肢和躯干运动的特点，为制定康复治疗方案提供理论依据。方法 选择15例完全性或不完全性C5，和C6水平SCI的四肢瘫患者，作为四肢瘫组，另选择15例正常人作为对照组。应用Peak Motus运动解析系统对所有受试者抓取杯子、触摸开关、驱动轮椅和利用上肢负重等4项伸肘活动的摄像资料进行三维运动学分析。结果 与对照组相比，四肢瘫组在4项伸肘活动中的运动速度明显减慢（P〈0．05或0．01）；除了利用上肢负重外，2组受试者在其余3项活动中上肢和躯干各标志点的位移比较，差异均无统计学意义（P〉0．05）。结论 在C5～C6水平SCI四肢瘫患者的康复治疗中，应加强肱三头肌和其它残存肌的力量训练并改善患者的躯干稳定性；运动学检测是定量评定四肢瘫患者运动功能及康复疗效的一种新方法。     

Effective and selective stretching of the medial head of the gastrocnemius

Muscle injury frequently occurs in the medial head of the gastrocnemius (MG), and stretching is used for treatment. However, there are no studies based on anatomical considerations and biomechanics. This study therefore examined the macroscopic anatomical structure of the triceps surae muscle to design an effective and selective MG stretching method, before quantitatively verifying that method by ultrasonography. The macroscopic anatomy was analyzed in 16 Japanese cadavers (25 legs). Based on the anatomical findings and the arrangement of fascicles in the MG, we concluded that ankle inversion might be advantageous for selective stretching of the tendon fiber bundles into which the MG inserts. We devised a method in which the limb was initially positioned with the knee joint in extension and the ankle joint in plantar flexion. Then, the ankle was dorsiflexed and inverted. The proposed method was compared with standard stretching and verified by ultrasonography in eight healthy adult males. This method effectively and selectively stretched the MG, producing a significantly decreased pennation angle and increased muscle fiber length. This method may be beneficial for preventing future injuries and may enhance the effect of therapy on the MG.     

Assessment of plantar flexors activation capacity: nerve versus muscle stimulation by single versus double pulse

This study was designed to investigate if the relationship between the interpolated twitch-torque (IT) and voluntary torque (VT) is affected by the number of electrical stimuli (single vs. double) and the stimulation site (nerve trunk vs. muscle). The results showed that the IT–VT relationship of the plantar flexors is appropriately described by a composite (linear + curvilinear) model. Indeed, whatever the stimulation method, the IT–VT relationship was linear between approximately 25 and 75% of the maximal voluntary torque (MVT) and curvilinear for higher contraction intensities. The four stimulation conditions are equivalent in assessing the maximal voluntary activation (VA% range 96.2 ± 5.0 to 98.5 ± 3.1%) as well as in determining the true maximal torque expected for total twitch occlusion (MT_exp range 171.4 ± 21.2 to 179.0 ± 26.8 Nm). The gap between the MVT and MT_exp should be viewed as an index of muscle inactivation. This gap was comparable for the four stimulation methods (2–6%) and close to the deficit in VA% (2–4%). No pulse-number effect was found on the IT–VT relationship when the nerve was stimulated but an effect on the concavity of the composite relationship was observed when the stimulation was applied over the muscle. Even though the four stimulation techniques are equivalent in assessing the maximal activation capacity our results demonstrate that the neural stimulation method is the most consistent as it guarantees the same motor pool recruitment independently from the number of pulses.