Neurotoxic effect of povidone-iodine on the rat spine using a laminectomy-durotomy model.

OBJECTIVE: The efficacy and safety of povidone-iodine in wound dressing and irrigation of some operative cavities were established by many in vitro and in vivo experimental reports and clinical series. However, its use in defective tissue in neural structures has not been confirmed yet. The aim of the present study was to histopathologically investigate its effect on neural tissues when applied on the upper side of defective dura.
METHODS: Wistar rats were randomly divided into two experimental groups: control and povidone-iodine groups. In the control group, durotomy was performed following laminectomy, and the spinal cord was covered with a dry sponge. In the study group, the same procedure was performed, but open duras were covered with a sponge that had been wetted with 0.1 % povidone-iodine solution. Three weeks after surgery, all experimental animals were sacrificed, and histopathological evaluations were conducted.
RESULTS: Myelin changes were absent or minimal in all cases of the control group but were present as markedly increased myelin degeneration in nearly all cases in the study group. Axonal degeneration and hypoxic neuronal damage were absent in the control group, whereas they were marked in half of the study group. No statistically significant differences were established in Schwann cell proliferation, venous congestion, and lymphocytic proliferation between the two groups.
CONCLUSIONS: Based on the present study, 0.1 % povidone-iodine solution cannot be recommended for wound dressing for neural structures such as myelomeningocele cases because of possible damage to underlying neural tissues.