Morphometric and neurophysiological analysis of skeletal muscle in paraplegic patients with traumatic cord lesion.

Morphometric and electrophoretic properties of soleus and medialis gastrocnemius fibres from paraplegic patients were studied 1 to 10 months following complete traumatic cord transection (spinal cord level C5-T1). In the short term of paraplegia (1-6 months) gastrocnemius medialis and soleus muscles showed predominant atrophy of IIA fibre types. In long term paraplegia (8-10 months) atrophy and reduction of type 1 fibres, with presence of high percentages of type IIB fibres, were seen in both studied muscles. The consistence in both muscles of IIB intermediate fibres in long term paraplegia, seems to indicate the initial stage of a mechanism of fibre transformation reflecting the adaptative capacity of the paretic muscle to spasticity. Electrophysiological studies of the H-reflex and the H/M ratio values reveal an increase of the H-reflex excitability in the soleus and gastrocnemius muscles during a 1 to 10 months follow-up.