Characteristics of <i>m. Psoas minor</i> and <i>m. Sacrocaudalis (coccygeus)</i> dorsalis lateralis in simultaneous modeling of lateral interbodial spinnylodesis and posterior sacro-iliac joint arthodesis

Abstract

BACKGROUND: Simultaneous surgical interventions on the spine with the use of high-tech instruments and minimally invasive access techniques allow to eliminate several problems all at once, to activate patients at an early date and to reduce the number of complications. AIM: To evaluate morphological changes to evaluate morphological changes in the m. Psoas minor and m. Sacrocaudalis dorsalis lateralis during simultaneous modeling of lateral interbody fusion and posterior sacroiliac joint arthrodesis MATERIALS AND METHODS: Experiments were carried out on 14 outbred dogs; 3 animals formed a control group. The animals underwent consecutive lateral interbody fusion of the lumbar spine and posterior arthrodesis of the sacroiliac joint. The lumbar spine and sacroiliac joint were stabilized with external fixation device. Paraffin sections of muscles were stained with hematoxylin-eosin, according to Van Gieson, and Masson. Biochemical analysis of blood serum was performed during the experiment. RESULTS: The morphological study of the muscles revealed pathohistological features such as an increase in the variety of myosymplast diameters, loss of their profiles polygonality, massive fibers fatty degeneration, endo- and perimysial fibrosis, sclerotization of vessel membranes, obliteration of their lumens. At the end of the experiment, the degree of the small lumbar muscle fibrosis was 161% and of the sacrocaudal dorsal lateral muscle fibrosis was 240% of the control parameters (p 0.05); the rate of the muscle fatty infiltration was 339 and 310% of the normal value, respectively. The sacroiliac-caudal dorsal lateral muscle underwent more marked changes, especially in the early stages of the experiment. A significant increase in the enzymes activity, skeletal muscle damage markers was detected on the 14th day after surgery. CONCLUSION: Simultaneous surgical interventions on the spine should minimize mechanical effects on the paravertebral muscles and use techniques to stimulate their function in the postoperative period, which will reduce the processes of fibrogenesis and fat involution as well as provide an overall shorter rehabilitation period for the target patients.