Muscle & nerve
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This review addresses the issue of how axotomy of peripheral nerve fibers leads to pain and hyperalgesia. The point of axotomy (the nerve injury site), the dorsal root ganglia, and the dorsal horn of the spinal cord are candidate sites for generation of the pain signal that is likely to be critical for maintaining the neuropathic pain state. This review considers neuropathic pain from a "systems" perspective, tracing concepts of neuropathic pain from the work of Henry Head to the present. ⋯ These abnormalities in the intact nociceptor, which arise in the context of Wallerian degeneration, probably play a role in creating or maintaining the abnormal pain state. These considerations probably also apply to the understanding of pain arising in other neuropathies. The findings relative to the "intact" nociceptor provide a rationale by which to understand how therapies distal to the nerve injury site may diminish pain.
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Phrenic nerve conduction studies were performed to assess the ipsilateral nerve in 100 patients with traumatic brachial plexus palsy. Open exploration and intraoperative recordings of somatosensory evoked potentials and nerve action potentials were used to confirm the level of root lesions. ⋯ We found C-5 preganglionic root lesions in 13 (100%) patients with severely injured, 5 (71.4%) with partially injured, and 24 (30%) with normal phrenic nerves. This correlation suggests phrenic nerve conduction study is a useful tool in the diagnosis of C-5 preganglionic root lesions in patients with traumatic brachial plexopathy.
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Case Reports
Brachial plexus neoplastic lesions assessed by conduction study of medial antebrachial cutaneous nerve.
Two cases of neoplastic involvement of the lower brachial plexus are reported. This condition was due to recurrence of lymphoma in one case and to axillary node spread of breast cancer in the other. ⋯ All other electrodiagnostic tests were normal. Such a finding suggests the need for imaging of the lower brachial plexus region by computed tomography or magnetic resonance imaging.
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Randomized Controlled Trial Clinical Trial
An innovative hand brace for carpal tunnel syndrome: a randomized controlled trial.
We developed a hand brace and studied its efficacy and tolerability in patients with carpal tunnel syndrome (CTS). We randomized 83 subjects into a treated group, which wore the hand brace at night for 4 weeks, and a control group, which received no treatment. The primary efficacy measure was change in the Boston Carpal Tunnel Questionnaire (BCTQ) score. ⋯ SGICQ documented improvement in all treated subjects (P = 0.006). No significant difference was found in electrophysiological measurements, but overall neurophysiological classification shifted to less severe classes in the treated group (P < 0.05). Thus, the study demonstrates that this hand brace is highly efficient in relieving symptoms and functional loss in CTS.
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We present the results of subcutaneous microdialysis, a new minimally invasive biochemical monitoring technique, in mitochondrial cytopathy. We studied 6 ambulatory patients with mitochondrial cytopathy and 6 controls without mitochondrial disease using a subcutaneous probe for continuous microdialysis, and obtained measurements of lactate, pyruvate, and glucose from samples gathered at 30-60 min intervals during the day and at 3-h intervals at night. The lactate:pyruvate ratio (LPR) was calculated and related to disease severity and metabolic stress. ⋯ Increases in the LPR coincided with metabolic stress in individual cases. We conclude that subcutaneous microdialysis is well tolerated and enables continuous metabolic monitoring of patients with mitochondrial cytopathy. It has particular potential for use in the identification of metabolic risk factors and may help to assess the impact of therapeutic regimens.