Complete Nerve Transection Research Articles

Intraorbital transection of the rabbit optic nerve: Consequences for ganglion cells and neuroglia in the retina

Rabbit retinae were stained with antibodies to glial fibrillary acidic protein (GFAP) at various times up to 5 months after complete unilateral intraorbital optic nerve transection, which is known to induce degeneration of ganglion cell axons and perikarya in the retina. A transient immunoreactivity for GFAP was observed in Müller glial cells that normally lack this marker. Müller-cell GFAP immunoreactivity became detectable 4 days after the lesion, but Müller cells were no longer labeled 3 months later. GFAP-labeled astrocytes located in the nerve fiber layer showed no change in immunoreactivity at any stage after transection. Application of horseradish peroxidase to the left and right superior colliculus of a rabbit whose optic nerve had been transected unilaterally 2 years before confirmed the completeness of the transection. Yet electron microscopy showed the presence of some healthy-looking ganglion cell axons in the lesioned retina, although these cells were deprived of their target. Labeling retinal wholemounts with neurofilament antibodies confirmed the presence of some ganglion cell axons and perikarya in the retina more than 2 years after transection. The course of these axons suggested that they were remnants of axons. Using antibodies to galactocerebroside (GC) we found that, as in the normal rabbit, these persisting ganglion cell axons were myelinated in the medullary rays. Although many ganglion cell axons had disappeared after 2 years, the number of neuroglial cells (including astrocytes and oligodendrocytes) present in the medullary ray region was not altered. The cell bodies of some oligodendrocytes were covered with a myelin sheath, an aberrant feature not seen normally.

The effects of polyamines and polyamine inhibitors on rat sciatic and facial nerve regeneration

The effects of exogenous polyamines and polyamine biosynthetic pathway inhibitors on regenerating nerves were examined in adult male rats following nerve transection and surgical repair. Several studies have demonstrated the efficacy of exogenous polyamines in promoting the functional recovery of peripheral nerves following crush or freeze injuries in the rat. In order to simulate clinical peripheral nerve surgery, we studied these effects after complete nerve transection and evaluated regeneration by counting axons. There was no statistical difference in axon number with and without polyamines and in the presence of inhibitors and inhibitors with end product addition. Our study suggests that the difference in recovery seen in previous studies is not mediated by a change in axon number.

Primary neoplasms of the facial nerve.

A series of 30 primary facial nerve tumors is reviewed. Most of them were benign (n = 26); there were four malignant tumors. Neoplasms originating within the temporal bone were found to have preoperative facial paralysis in 84 percent of cases; the extracranial tumors had a 35 percent incidence of preoperative facial paralysis. All tumors in this series were treated surgically--by means of a middle fossa or transmastoid approach for the intratemporal group of tumors; the extracranial tumors were removed by the technique of parotid tumor surgery with complete facial nerve dissection. All the patients with preoperative facial weakness required facial nerve transection. Facial paralysis was rehabilitated with nerve grafts, hypoglossal crossover, or muscle transfers. Because "normal" facial expression is still not attainable following repair of complete facial nerve transection, an early diagnosis, hopefully prior to total neurotmesis, is essential. All patients with unexplained facial weakness, especially that which is progressive and persistent, should have the entire course of the facial nerve investigated for the possibility of treatable etiology.

Interfascicular transplantation in median nerve injuries.

Twenty-four patients operated upon within a 3-year period for complete median nerve transection using the microsurgical interfascicular transplantation technique were examined after a minimum of 3 years' observation. Functional motoricity (M 3 or higher) was achieved by 83 per cent. With the exception of one patient, all achieved protective tactile sensibility (96 per cent). The results were best for distal lesions in children and youths. The outcome was just as satisfactory as that attained with epineurial suture carried out under ideal conditions. The method was found to be superior to epineurial end-to-end suture in cases of nerve defects longer than 2.5 cm.

Acetyl-CoA synthetase, NADP malate dehydrogenase and ATP citrate lyase in the degenerating peripheral nerve

Summary The specific activity (activity/mg protein) of three enzymes has been measured in the distal segment of the rat sciatic nerve during Wallerian degeneration obtained by complete nerve transection. The three enzymes are acetyl-CoA synthetase, NADP malate dehydrogenase and ATP citrate lyase. It has been found that the specific activity of all the three enzymes undergoes an early increase followed by a fast return to normal or subnormal values. An attempt has been made to integrate these findings in the sequential pattern of early enzyme changes which occur in the peripheral nerve of mammals during Wallenrian degeneration.

Neuralgia of the trigeminal, glossopharyngeal and vagus nerves

Os autores apresentam um caso com sintomatologia dolorosa nos territórios de distribuição do 5º, 9º e 10º nervos cranianos à direita, de etiologia não elucidada, e rotulado como neuralgia essencial. O tratamento realizado foi o cirúrgico, sendo praticada, num primeiro tempo, a cavólise9, seguida de neurotomia intracraniana do glossofaríngeo e da porção anterior do pneumogástrico. Como houvesse recidiva 6 meses depois, sugerindo que a neuralgia decorresse da irritação da porção restante do nervo pneumogástrico, foi feita nova intervenção cirúrgica, sendo seccionado o restante dêste nervo, com excelente resultado.