[Clinically significant histologic, histochemical and morphometric parameters in the evaluation of muscle biopsies]

Many of the diagnostic advances in the field of myopathies have been achieved by the examination of samples of muscle removed by biopsy. A muscle selected for biopsy must be obtained atraumatically with the fibres orientated longitudinally. Artefacts are avoided by freezing the sample in liquid nitrogen. The typing of muscle fibres by using the ATPase and dehydrogenase reactions is of advantage to the interpretation of muscle diseases. An accurate method for the determination of changes in the size of muscle fibres is a must. The construction of histograms, standard values for mean fibre diameters, the estimation of the proportion of various types of fibres, variability coefficient, atrophy and hypertrophy factors are a help. A few studies have been performed concerning the effect of a physical therapy on the composition of the fibres of skeletal muscles. A more differentiated physiotherapeutic treatment based on the histochemical and morphometrical results of the muscle biopsy is essential for the therapy of the myopathies.