Progressive scoliosis in early, non-progressive CNS injuries: role of axial muscles.

Forty-three patients with progressive neurological deficits involving axial musculature, starting 3-6 years after non-progressive brain injuries insults are described. Losses of function followed period of several years of stable motor deficits. Subsequent losses were stereotypic, with loss of ambulation and scoliosis, followed by loss of word articulation, malalignment of the mandible and ultimately neurogenic impairment of swallowing. Physical therapy, serial castings and spinal instrumentation palliated specific musculoskeletal problems but did not alter the relentless loss of various functions. The balanced action of paired axial muscles (i.e. spine, proximal muscle groups of the lower extremities, oropharynx, mastication) is regulated by the brainstem with modulation by the cerebral hemispheres. The clinical evolution in these patients suggest that, in the absence of normal input from the cerebral hemispheres, some patients have a progressive loss of these brainstem mechanisms. The most resistant functions (last ones to be lost), seem to be the ones phylogenetically most relevant for survival, such as suction and swallowing.