Long-standing facial paralysis rehabiltation.

Abstract

AbstractA group of 32 patients with severe facial paralysis from 2 to 30 years and of different etiologies were studied. Various degrees of nerve and muscle atrophy were noted in this group. A new concept relative to the status of the paralyzed face, its nerve and muscle system and their capacity for rehabilitation was acquired.The treatment of long‐standing paralysis has been relegated to fascial stripping, muscle slings, tarsorrhaphies and face‐lift operations. This investigation indicates that the situation is not totally irreversible. The determinant factors are the number of surviving axones and the viability of the facial muscles supplied by them. Regardless of the electrical testing, the facial nerve never totally disappears nor do the facial muscles. On surgical exploration, the facial nerve and the posterior belly of the digastric muscle were always recognizable in varying degrees of atrophy and fibrosis. A range of 20‐90 percent of normal size was noted.Electron microscopy of the nerve and muscles demonstrated axone degeneration still taking place and muscle fibers present in cases 20‐30 years post injury to the nerve. The degree of atrophy and fibrosis was dependent upon the length of the paralysis. It was also noted that the degree of severity was less as the site of injury became more peripheral. This was probably related to the rich extratemporal nerve interconnections from the sympathetics, cervical plexus, and cranial nerves V and IX. These findings verified the existence of a subliminal system which is non‐functional, but in certain instances had the potential for rehabilitation.Some of the most interesting aspects of facial rehabilitation in longstanding facial paralysis are beginning to unfold themselves in the recognized potential of a regrowth of axones in a depleted but not annihilated facial nerve system by nerve crossover and nerve grafting techniques. When the peripheral facial nerve system is absent, nerve implantation into the residual mimetic muscles or transposed masticatory muscles is indicated. The introduction of masticatory muscles into the face to accommodate this neural regrowth, when mimetic muscle potential remains subclinical, adds a new neuromuscular facility in the rehabilitation.