Is Tranexamic Acid an Effective Prevention in the Formation of Epidural Fibrosis? Histological Evaluation in the Rats

Abstract

Objective: The present study aimed to determine the topical and systemic efficacy of tranexamic acid (TXA) on epidural fibrosis in a rat laminectomy model.

Methods: Thirty-two 12-month-old adult Sprague-Dawley rats were used in this study. Each rat underwent bilateral laminectomy at the L1 and L2 vertebral levels. Rats were divided into four groups : in group I (control group, n=8), a laminectomy was performed and saline solution was applied into the surgical space. In group II (topical group, n=8), laminectomy was performed and 30 mg/ kg TXA was applied to the surgical site before skin closure. In group III (systemic group, n=8), 30 mg/kg TXA was administered intravenously via the tail vein in the same session as the surgical procedure. In group IV (topical and systemic group, n=8), TXA was administered 30 mg/kg both topical and intravenous. The rats were sacrificed at 4 weeks postoperatively. Masson's trichrome and hematoxylin and eosin were used to assess acute inflammatory cells, chronic inflammatory cells, vascular proliferation, and epidural fibrosis.

Results: Epidural fibrosis, acute inflammation, chronic inflammation, and sum histologic score value were significantly lower in the systemic TXA group, systemic and topical TXA groups than in the control group (p<0.05). In addion, the sum histologic score was significantly lower in the topical TXA group than in the control group (p<0.05).

Conclusion: In this study, epidural fibrosis formation was prevented more by systemic application, but the topical application was found to be effective when compared to the control group. As a result, we recommend the systemic and topical use of TXA to prevent epidural fibrosis during spinal surgery.

Keywords: Epidural fibrosis; Laminectomy; Rats; Tranexamic acid.

Fig. 1.

Laminectomy at the L1 and L2 vertebral levels.

Fig. 2.

A and B : Grade 1 epidural fibrosis (EF) section from the systemic and topical tranexamic acid (TXA) group thin arrows designate the stage 3 vascular proliferation site at the interface between the dura and scar tissue. Thick arrows indicate dura mater was free of scar tissue. A residual hemostatic agent was not observed (A : Hematoxylin and Eosin [H&E], ×40; B : Masson’s trichrome, ×40). C and D : Grade 3 EF section from the control group. EF covered the whole laminectomy defect with a wide adherence to dura mater (arrows). The mass effect of a large amount of scar tissue is observed in the control group, which causes deformation of the dural tube (C : H&E, ×100; D : Masson’s trichrome, ×100). SC : spinal cord.

Fig. 3.

Comparison of the mean histologic sum score among groups. ^*Mann-Whitney U test. TXA : tranexamic acid.