Longitudinal and vertical ultrastructural lesion of crural muscle in post-thrombotic syndrome.

The vertical and longitudinal ultrastructural changes of the crural muscle (triceps surae) were studied in a selected patient material of 18 patients suffering from post-thrombotic syndrome. The transmission and scanning electron microscopic method helped in revealing that the damage had affected the contractile system, the mitochondria and the endoplasmic reticulum and in addition marked degenerative phenomena occurred. It was shown that vertically the impairments of the fine structure were localized in foci and involved the muscle layers to the same extent. Longitudinally--distally--the muscle changes displayed an increasingly aggravating diffuse appearance. Of the several factors responsible for the development of the pathological ultrastructural picture, tissue hypoxia and metabolic disorder, as well as a decreased microcirculation (hypoperfusion) and chronic inactivity are to be emphasized.