Histopathological changes in paravertebral muscles by chronic discopathies

Samples of paravertebral muscles were obtained from the lesion sites of forty patients operated on for recurrent lumboischiadic syndrome of discogenic etiology. None of the specimens was physiological. All of them were pathologically altered in various grades of involvement. The histopathological changes were highly varied. The findings included muscle fibre atrophy of a nonspecific type, neurogenic atrophy of typical fascicular distribution. Apart from atrophic fibres there were hypertrophic ones either at the same time or in connection with another histopathological process. Changes of myopathic nature were also present with rounded up muscle fibres and shift of nuclei from the subsarcolemnic spaces into the centre of the muscle fibre, multiplication of the connective tissue and vicarious growth of adipose tissue. The visible neuromuscular spindles contained thickened connective tissue capsules and atrophied intrafusal fibres. The present authors' conclusion of their interpretation of these histopathological changes is that they are not produced by one but by a whole set of factors. What results is a cyclic nature of the changes, when it is hard to decide whether we are facing a primary cause or its sequela. The regular company of discopathies are repeated microtraumas during recurrent paravertebral contractures and spinal blocks. A not negligible part can be played also by primary muscle diseases affecting, among others, back muscles, e.g. progressive muscular dystrophy of Duchenne's and Becker's type, various myopathies, nonspecific myositis and paravertebral polymyositis, and other rheumatological involvement. These muscular diseases with disturbed proprioception causing unphysiological posture and loading the spine can share in the origin degenerative processes on intervertebral disks.