Experimental study of the dura mater-bone graft interface

• Grant number: 22/04985-0
• Support Opportunities: Regular Research Grants
• Start date: March 01, 2023
• End date: July 31, 2025
• Field of knowledge: Health Sciences - Medicine - Surgery
• Principal Investigator: Flávio Luís Garcia
• Grantee: Flávio Luís Garcia
• Host Institution: Faculdade de Medicina de Ribeirão Preto (FMRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
• Associated researchers: Ariane Zamarioli
• Associated scholarship(s): 23/04226-5 - Fibrotic tissue formation at the interface of the dura mater with the bone graft, BP.TT

Abstract

Surgical exposure of the dura mater, after removal of the surrounding bone tissue and ligaments in the spine, may induce the development of epidural fibrosis during the post-surgical repair and healing process. Epidural fibrosis causes nerve root traction, restriction of nerve root movements, extradural compression, and decreased arterial supply to the nerve root, resulting in a major cause of spinal surgery failure, with recurrence of pain. The creation of barriers with biological or synthetic materials between the dura mater and the scar tissue has been used to prevent or reduce the formation of epidural fibrosis. However, to date, there is no absolutely effective technique for this purpose. The objective of this study is to evaluate the interface between the dura mater and the bone graft placed on it after the removal of the posterior elements of the vertebral segment (vertebral laminae and ligaments), by light microscopy and in different postoperative periods. The hypothesis to be tested is that the bone graft could act as a biological barrier to reduce epidural fibrosis and that its placement on the dura mater will not induce deleterious effects on adjacent nerve structures, with less fibrosis formation around it. Thirty Wistar rats will have the vertebral laminae and posterior ligaments removed at the T10 and T12 levels and the dura mater exposed. Bone fragments removed from the T10 and T12 vertebral laminae will be cut into small fragments and placed on the dura mater at the level of T10. At the T12 level, no bone graft will be placed on the dura mater, and will be used as a control. To ensure impartiality and experimental randomness, we will alternate the placement of the bone graft on the dura mater at T10 and T12 levels. Experimental groups will be formed according to the moment of euthanasia of the animals in the post-operative period. Each experimental group will consist of six animals and the euthanasia will be performed 4, 6, 8, 12 and 16 weeks after the surgical procedure. The dura mater reaction to the contact with the bone fragments will be evaluated through histological study using light microscopy. (AU)