Journal of orthopaedic science : official journal of the Japanese Orthopaedic Association
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We studied the efficacy of mexiletine as a sodium channel blocker for neuropathic pain by investigating the effect of mexiletine on the pathological ectopic firing pattern in a chronic constriction nerve injury (CCI) model. The experiment was conducted with 60 male Wistar rats. The CCI model was created by loosely ligating the sciatic nerve. ⋯ Mexiletine did not influence the amplitude of A-delta component in the antidromic sensory nerve-evoked potential. Mexiletine suppressed ectopic firing by blocking activity of the abnormal sodium channel at the nerve-injured site and dorsal root ganglion without blocking nerve conduction. This study suggests that mexiletine is useful for treating neuropathic pain in peripheral neuropathy.
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We have developed a new intramedullary nail (All-in-One Nail) that is specifically designed for elastic fixation of a surgical neck fracture of the humerus. This nail has three pins and a plate, and the pins become divergent as the nail is inserted into the marrow cavity through the deltoid tuberosity and then advanced to the humeral head. ⋯ Bony union was obtained in 29 patients, and these patients had a Japanese Orthopaedic Association shoulder score of 60-92 (mean 78) in a follow-up examination performed 6-32 months (mean 13 months) postoperatively. The All-in-One Nail system is easy to use, provides an acceptable clinical outcome, and is a treatment option for unimpacted surgical neck fractures and valgus-impacted fractures of the humerus.
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Spinal implants retrieved from 11 patients with scoliosis were examined. All the implants were posterior instrumentation systems made of 316L stainless steel and composed of rods, hooks, and crosslink connectors. Corrosion was classified into grades 0 to 3 based on macroscopic findings of the rod surface at the junction of each hook or crosslink connector. ⋯ It is thought that intergranular corrosion and fretting contributed to the corrosion of implants. The current study demonstrated that corrosion takes place at many of the rod junctions in long-term implantation. We recommend removal of the spinal implants after solid bony union.
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To investigate the nerve root distribution of deltoid and biceps brachii muscle, compound muscle action potentials (CMAPs) were recorded intraoperatively following nerve root stimulation in cervical spondylotic myelopathy. A total of 19 upper limbs in 12 patients aged 55-72 years (mean, 65.5 years) with cervical spondylotic myelopathy were examined. CMAPs were recorded from deltoid and biceps brachii muscle following C5 and C6 root stimulation. ⋯ The C5 root predominantly innervated both deltoid and biceps brachii in patients with symptomatic cord lesions at the C4-C5 intervertebral level compared to patients with symptomatic cord lesions at the C5-C6 intervertebral level. Although no patients sustained postoperative radiculopathy in our study, severe weakness and unfavorable recovery are expected when the C5 root in patients with C4-C5 myelopathy is damaged. From the electrophysiological aspect, C4-C5 cord lesions are likely to be a potential risk factor for postoperative shoulder muscle weakness in patients with compressive cervical myelopathy.
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Review Case Reports
Transient talipes equinus deformity of bilateral lower limbs following malignant hyperthermia: a case report and review of literature.
Malignant hyperthermia (MH) is a potentially fatal disease triggered by general anaesthesia. Four cases of compartment syndrome complicating MH have been reported. ⋯ MRI revealed high intensity in the bilateral soleus muscles but not in the gastrocnemius muscles. We discuss the possible mechanisms of the deformity of the lower limbs after the MH crisis.