Degeneration and regeneration of nerves following cryosurgery.

Ventral epithelium of the tongue was frozen by means of a surface applied cryosurgical probe. Nerves in the sub-epithelial connective tissue were examined in the electron microscope at various time intervals after thawing. Degeneration commenced immediately on thawing of the tissues and regeneration was well advanced within one week of the injury. Degeneration occurred before ischaemia could be expected to have produced nerve damage and it is suggested that the initial insult is a cryolytic one. Although nerve function was not studied in the present experiments, the structural changes were in accord with clinical findings of reduced sensitivity during and immediately following cyrosurgery and also with recovery of function within 7-14 days of the injury.