Histochemical and histological changes of paraspinal muscles in patients with thoracic and lumbar spine fractures treated with open and minimally invasive stabilisation

BACKGROUND: Histological and histochemical analyses of muscle samples were used to determine the intensity of paraspinal muscle injury during open (OPEN) and minimally invasive (MIS) procedures due to spinal trauma. OBJECTIVE: A randomised prospective study design was chosen. According to our hypothesis, OPEN procedures will lead to more intensive microscopic changes than MIS. METHODS: Muscle samples were collected during the primary surgery - fracture surgery (FRS) from the left and during material extraction (EXS) from the right side. Complete samples were acquired from 17 OPEN and 18 MIS subjects. We compared them histochemically and histologically; muscle fibre typing and statistical analysis were performed. RESULTS: We statistically confirmed that the increase in fibrosis in the OPEN EXS sample was significantly higher than in the MIS EXS sample, with p< 0.05 (p= 0.000322453). Fibre types in MIS did not differ almost at all in both samples; the changes were statistically insignificant.In OPEN samples, the number of type I fibres differed significantly. In EXS, it was significantly lower (46.23%) than in FRS (60.63%), at a statistically significant level, p< 0.05 (p= 0.0234375000) especially with the increase of the type IIA fibres, less in IIB fibres. CONCLUSIONS: These microscopic findings provide a statistically significant confirmation that OPEN procedures in spinal fracture lead, in most cases, to significant changes in the structure of the corset muscle at the fracture site and surgical access point than MIS procedures.