Change of the Shape of the Dural Sac in the Laminectomy Model at Different Stages of the Reparation in the Experiment

Abstract

Epidural fibrosis is a dynamic pathological process that develops and progresses over time and is a polyetiological and multifactorial complication in the postoperative period during spinal surgery.Aim of the study. To study the reparative process and the formation of epidural fibrosis and its effect on the shape of the dural sac in the area of laminectomy at different periods of wound healing.Materials and methods. To assess the dynamics of the formation of epidural fibrosis and the involvement of the dura mater in this process, laminectomy was performed at the level of the LVI vertebra in 35 male Wistar rats at the age of 4–5 months. The animals were divided into 5 periods of withdrawal from the experiment on days 3, 7, 14, 21, and 28. The histological material was studied by staining with hematoxylin and eosin. To assess the deformation of the dural sac, the ratio of the diameter to the length of the canal was assessed on histological preparations in the laminectomy zone, and these measurements were carried out in a group of intact animals at the level of the LVI vertebra (n = 7). Results. During the observation process, a change in the ratio of the sizes of the dural sac has been observed. In the period from days 3 to 14, the anterior-posterior size of the dural sac progressively decreases, in parallel, the transverse size increases, which leads to a change in its shape. On follow-up, some form correction occurs. It is possible that the change in the shape of the dural sac in terms of up to 14 days is due to edema, plasma saturation of tissues, as well as the growth of connective tissue. The subsequent decrease in edema and the restructuring of the newly formed connective tissue leads to a correction of the shape of the dural sac.Conclusion. In the work, the dynamics of morphological changes in the zone of formation of epidural fibrosis during laminectomy in the experiment was assessed. The dynamics of changes in the lumen of the dural sac was established. The early involvement of the dura mater in the pathological process, its interest during the entire observation period was noted. Also, histological preparations show the involvement of the nerve fibers of the cauda equina in the pathological process from the early stages after surgery: vacuolization and destruction of nerve fibers, adhesion of fibers to each other and to the dura mater, as well as activation of endotheliocytes in the vasa nervorum.

Keywords

• laminectomy
• morphometry
• dural sac
• epidural fibrosis
• dura mater
• reparation
• experiment