Chitosan Dextran gel as an anti adhesion agent in a postlaminectomy spinal sheep model.

INTRODUCTION: Post-operative peridural adhesions increase morbidity after neurosurgical procedures. Aim of this study is to assess safety and efficacy of Chitosan-Dextran (CD) gel as an anti-adhesion agent in a spinal laminectomy sheep model. METHODS: Eighteen sheep were used in this study with 6 animals in each treatment arm (namely, CD gel, Gelfoam paste and normal saline control). Posterior lumbar laminectomy was performed in all animals and the dura was exposed intact. Test agents were applied over the exposed dura and the wound was closed in layers. Sheep were euthanized at the end of three months. MRI spine was performed after euthanasia to assess epidural fibrosis. Adhesion in the spinal specimen was assessed by Peel test and histopathology was used to assess safety of the agents. RESULTS: Average scores for the Peel test for CD gel, Gelfoam and normal saline control groups were 1.16 (95% CI, 0.5-1.7), 1.5 (95% CI, 0.6-2.3) and 3 (95% CI, 2.1-3.8) respectively. There was significant reduction in adhesions between treatment and normal saline treated groups (p=0.0292), with no difference between Gelfoam and CD gel groups (p=0.56). Average scores on MRI for CD gel, Gelfoam and normal saline groups were 1.4 (95% CI, 0.9-1.8), 1.5 (95% CI, 1.2-1.8) and 1.6 (95% CI, 1.3-1.8) respectively, with no significant difference in fibrosis amongst (p=0.2992). Histopathology did not show any adverse effects. CONCLUSION: CD gel is an effective agent to reduce epidural adhesions with a good safety profile in neural tissue.

The efficacy and safety of chitosan dextran gel in a burr hole neurosurgical sheep model.

BACKGROUND: Achieving and maintaining haemostasis is of paramount importance in neurosurgery. Chitosan has been shown in both animal and human models to be significantly effective in haemostasis as well as in reducing adhesion formation. OBJECTIVES: To evaluate the haemostatic potential and to study histopathological changes caused by novel chitosan dextran gel in a neurosurgical sheep model. METHOD: Ten sheep underwent neurosurgical burr hole procedure. Bleeding control was tested at the level of bone, dura and brain separately with both chitosan gel and Gelfoam paste on separate burr holes. Baseline bleeding was measured at the time of injury using the Boezaart scale, and then every 2 min after the application of each agent until complete haemostasis or 10 min, whichever was earlier. Safety was assessed through MRI scans and histopathological analysis. RESULTS: Mixed modeling showed no statistical difference in time to haemostasis between chitosan gel and Gelfoam paste (means of log-normalized areas under the curve were 1.3688 and 1.3196 respectively) for each burr hole (p = 0.7768). Logistic regression modeling showed that Chitosan significantly decreased the incidence of bleeding beyond the first time point measured after application of the treatment when compared to Gelfoam (OR = 2.7, p = 0.04). Average edema volume (cm(3)) on post-operative MRI was 0.97 for Gelfoam and 1.11 for (p = 0.49) while average histology scores were 2.5 for Gelfoam versus 3.3 for chitosan (p = 0.32). CONCLUSION: Chitosan dextran gel is an effective haemostatic agent to control bleeding in brain tissue. It is safe and nontoxic to neural tissue.