Cryoanalgesia. Ultrastructural study on cryolytic lesion of sciatic nerve in rat and rabbit.

The sciatic nerve was exposed to cryoinjury at different freezing patterns in albino rats and rabbits and the frozen nerves were serially examined with electron microscopy from the time of cryolitic lesion (--60 degrees C for 3 minutes) for up to 28 days. The cryolesion was characterized by a total degeneration of the myelin fibers, while non-myelin fibers and vessels seemed less affected. Regeneration began 8 days after cryolysis. A peculiar pattern was the absence of Schwann cells, while the basal membrane around regenerating axons remained intact. The hypothesis that the basal membrane might play a role is discussed.

Surgical treatment of spasticity in cerebral palsy.

Since 1971, we have surgically treated spasticity in 109 cases of cerebral palsy with posterior rhizotomy. The best results have been obtained with functional posterior rhizotomy, an original modification of Foerster's technique, in which the selection of the roots/rootlets to be sectioned is based on functional exploration of the spinal circuits involved in the maintenance of spasticity, using intraoperative electrostimulation on dorsal roots. This method makes selective sections possible, thereby saving a larger number of normal proprioceptive afferents, with consequent reduction in negative side effects. No recurrencies have been observed in our 3-year follow-up. The main indication is Little's disease.

[Functional posterior radiculotomy, in the treatment of cerebral spasticity. peroperative electric stimulation of posterior roots and its use in the choice of the roots to be sectioned]. / La radicotomie postérieure fonctionnelle dans le traitement de la spasticité cérébrale Premieres observations sur la stimulation électrique peropératoire des racines postérieures, et leur utilisation dans le choix des racines ã sectionner

The authors present a modification of Foerster's Rhizotomy for the treatment of spasticity in cerebral palsy: functional posterior rhizotomy. The selection of the roots/rootlesses to be sectioned, is accomplished on functional data, based upon the analysis of the reflex responses to the intraoperative lumbar dorsal roots stimulation. With this method it is possible to selectively interfere with the pathological circuits responsible for hypertonia, saving proprioceptive afferences necessary for motor reeducation. The clinical results on hypertonia are the same as for total or partial rhizotomies, but sides effects (ataxia, hypotonia) are considerably reduced.