Predegenerated nerve allografts versus fresh nerve allografts in nerve repair.

This study reevaluated the possibility of using predegenerated nerves as donor nerve allografts for nerve repair and compared the results of functional recovery to those obtained after standard, fresh nerve allograft repair. Twenty donor rats underwent a ligature/ section of the left sciatic nerve 4 weeks before nerve graft harvesting. Forty recipient rats underwent severing of the left sciatic nerve leaving a 15-mm gap between the nerve stumps. Graft repair was undertaken using either the predegenerated left sciatic nerve of the 20 donor rats (predegenerated group, 20 recipient rats) or the normal right sciatic nerve of the 20 donor rats (fresh group, 20 recipient rats). Recovery of function was assessed by gait analysis, electrophysiologic testing and histologic studies. Walking tracks measurements at 2 and 3 months, electromyography parameters at 2 and 3 months, peroperative nerve conduction velocity and nerve action potential amplitude measurements at 3 months, as well as assessments of myelinated nerve fiber density and surface of myelination showed that fresh and predegenerated nerve grafts induced a comparable return of function although there was some trend in higher electrophysiologic values in the predegenerated group. The only slight but significant difference was a larger mean nerve fiber diameter in the nerve segment distal to a predegenerated nerve graft compared to a fresh nerve graft. Although our study does not show a dramatic long-term advantage for predegenerated nerve grafts compared to fresh nerve grafts, their use as prosthetic material is encouraging.

Recurrent ganglion cyst of the peroneal nerve: radiological and operative observations. Case report.

This 34-year-old man presented with right leg pain and foot drop of 1-month duration. The preoperative diagnosis of a 10-cm-long ganglion cyst of the peroneal nerve was achieved using ultrasonography (US), computerized tomography and, particularly magnetic resonance (MR) imaging. Surgical exploration disclosed a lobulated cystic mass filled with gelatinous material, which intermingled with the nerve substance of the deep peroneal nerve. The lesion was completely resected, with the sacrifice of some electrically nonfunctioning fascicles. No connection with the knee joint was found. A good postoperative recovery of motor function was obtained. However, routine postoperative MR imaging disclosed a recurrent ganglion cyst that was slightly less extensive than the original. A careful radiological examination of the knee joint was performed, including arthrography. A communication of the cyst with the tibiofibular joint was clearly demonstrated and was meticulously closed at reoperation. The patient's postoperative course was uneventful, and a third MR image, obtained 5 months after reoperation, showed no sign of cyst recurrence. The patient remained free of symptoms 11 months postoperatively. This case illustrates the value of US and MR in diagnostic imaging. The diagnostic efficacy of US and MR imaging in identifying and characterizing a ganglion cyst is described. Close contact between a ganglion cyst and the tibiofibular joint should raise the possibility of an existing cyst-joint communication and lead to an aggressive radiological workup and/or a surgical search for such a communication.

Posterior subscapular approach to the brachial plexus. Report of 102 patients.

A 15-year operative experience with 105 posterior subscapular approaches to the brachial plexus in 102 patients is presented. The procedure is indicated in carefully selected cases, especially where the proximal portions of lower spinal nerves are involved. Its main advantage is proximal exposure of the plexus spinal nerves, particularly at an intraforaminal level. The indications in this series were thoracic outlet syndrome (TOS) in 51 carefully selected procedures, brachial plexus tumor involving proximal roots in 22 patients, post-irradiation brachial plexopathy in 14 cases, and proximal traumatic brachial plexus palsy in 18 patients. Thoracic outlet syndrome associated with neurological loss, recurrent TOS after a prior operation, or proximal brachial plexus surgical lesions involving the spinal nerve(s), especially at an intraforaminal level, can be approached advantageously by such a posterior subscapular approach. The technique should also be considered when prior operation, trauma, or irradiation to the neck or anterior chest wall make a posterior exploration of the plexus easier than an anterior one. Anterior exposure of the plexus is the preferable approach for the majority of lesions needing an operation, but the posterior subscapular procedure can be useful in well-selected cases.

Sciatic nerve regeneration across gaps within collagen chambers: the influence of epidermal growth factor.

The effects of Epidermal Growth Factor (EGF) on axonal regeneration of a sectioned sciatic nerve within collagen tubes were investigated in 15 rats. Following baseline electrophysiologic assessment, bilateral 7-mm nerve gaps were created and repaired by interposition of collagen tubes, into which EGF (left side) or type I collagen (right side) was instilled. After 4 or 8 weeks, axonal regeneration, measured by electrophysiologic and histologic means, was identical for the EGF and control legs. The conclusion is that EGF does not influence nerve regeneration within a collagen chamber.

Is laser repair effective for secondary repair of a focal lesion in continuity?

It is possible to seal nerve ends together with the laser, and this can be effective for sharp injuries that are repaired relatively acutely or primarily. The possibility of utilizing the laser for secondary nerve repair after resection of a lesion in continuity was investigated in a rat sciatic nerve model. After baseline recording of nerve and muscle action potentials (MAP), a 3-mm-long crush injury of the sciatic nerve was performed bilaterally in 12 rats. Two weeks later, the crushed segment was resected, and the nerve on one side was repaired by end-to-end anastomosis using epineurial sutures and on the other side by sealing the nerve ends together with the CO2 laser. At reexploration 50 days postoperatively, all 12 suture repairs were anatomically in continuity and conducted a nerve action potential (NAP), while 10 of the 12 laser-repaired nerves had distracted. Laser repairs not distracted showed electrical and histologic evidence of regeneration. It is concluded that laser repair is not effective for delayed repair of lesions in continuity unless tension at the repair site can be lessened.