Peripheral nerve injury occasionally causes chronic neuropathic pain with hyperalgesia and allodynia. However, its treatment is difficult. Here, we used a chronic constriction injury (CCI) model in rats to investigate the effects on experimental neuropathic pain of the human hepatocyte growth factor (HGF) gene delivered into the nervous system by retrograde axonal transport following its repeated intramuscular transfer, using liposomes containing the hemagglutinating virus of Japan (HVJ). CCI (control) rats exhibited marked mechanical allodynia and thermal hyperalgesia, and decreased blood flow in sciatic nerve and hind paw. All these changes were significantly reversed by HGF gene transfer. In the sciatic nerve in HGF-treated rats, the size-frequency distributions for myelinated and unmyelinated axons each showed a rightward shift, the number of myelinated axons >5 microm in diameter was significantly increased, and the mean diameter of unmyelinated axons was significantly increased (versus CCI rats). Levels of P2X3, P2X4, and P2Y1 receptor mRNAs, and of interleukin-6 (IL-6) and activating transcription factor 3 (ATF3) mRNAs, were elevated in the ipsilateral dorsal root ganglia and/or sciatic nerve by CCI, and these levels were decreased by HGF gene transfer. These results may point toward a potential new treatment strategy for chronic neuropathic pain in this model.

Background:Shoulder rotational muscles act as dynamic stabilizers of the glenohumeral joint, and the recovery of muscle strength plays an important role in stabilizing the joint during postoperative rehabilitation. However, temporal changes in muscle strength after arthroscopic Bankart repair have not been clarified.Purpose:To better understand the temporal recovery of shoulder rotational muscle strength after arthroscopic Bankart repair.Study Design:Case series; Level of evidence, 4.Methods:Isokinetic concentric shoulder rotational muscle strength was evaluated in 50 patients who were diagnosed with recurrent dislocations of the glenohumeral joint and treated with arthroscopic Bankart repair.Results:The mean peak torque/weight and total work were reduced significantly at 1.5 months after surgery (P < .0001) and returned to preoperative levels by 6 months for external rotation and 4.5 months for internal rotation. The contralateral peak torque ratios reached preoperative levels by 6 months after surgery. The ipsilateral peak torque ratios were reduced between 1.5 and 3 months after surgery and returned to preoperative levels at 6 months for external rotation and 4.5 months for internal rotation.Conclusion:Isokinetic shoulder rotational muscle strength after arthroscopic Bankart repair recovered to preoperative levels by 6 months for external rotation and 4.5 months for internal rotation.

Glucagon-like peptide-1 (GLP-1) is glucose-dependent insulinotropic hormone secreted from enteroendocrine L cells. Its long-acting analogue, exendin-4, is equipotent to GLP-1 and is used to treat type 2 diabetes mellitus. In addition, exendin-4 has effects on the central and peripheral nervous system. In this study, we administered repeated intraperitoneal (i.p.) injections of exendin-4 to examine whether exendin-4 is able to facilitate the recovery after the crush nerve injury. Exendin-4 injection was started immediately after crush injury and was repeated every day for subsequent 14 days. Rats subjected to sciatic nerve crush exhibited marked functional loss, electrophysiological dysfunction, and atrophy of the tibialis anterior muscle (TA). All these changes, except for the atrophy of TA, were improved significantly by the administration of exendin-4. Functional, electrophysiological, and morphological parameters indicated significant enhancement of nerve regeneration 4 weeks after nerve crush. These results suggest that exendin-4 is feasible for clinical application to treat peripheral nerve injury.

Most injuries to the femoral nerve are iatrogenic in origin and occur during resection of large retroperitoneal tumours. When the defect is considerable a nerve graft is mandatory to avoid tension across the suture line. We describe two cases of iatrogenic femoral nerve injury which recovered well after reconstruction with long sural nerve grafts. The probable reasons for success were that we performed the grafting soon after the injury, the patients were not too old, the nerve repairs were reinforced with fibrin glue and electrical stimulation of the quadriceps was administered to prevent muscle atrophy. Good functional results may be obtained if these conditions are satisfied even if the length of a nerve graft is more than 10 cm.

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