A rabbit model for evaluation of spinal anesthesia: chronic cannulation of the subarachnoid space

A rabbit model for evaluation of spinal anesthesia is presented. Chronic cannulation of the subarachnoid space was performed in 44 rabbits using the translumbar approach. An autopsy was performed 24 h after the operation on four of the animals. Intrathecal injections of methylene blue did not reveal any leakage from the spinal space. X-ray examination performed on the second and 30th days after the implantation indicated free spread of the injected solution in the subarachnoid space without any obstruction. Repeated injections of four identical doses of bupivacaine at 3-day intervals showed reproducible pharmacologic effects. Administration of different doses of the anesthetic produced a clear dose-response relationship. The relative activity of the anesthetic agents was found to be identical to that previously obtained in humans. No significant complications after the implantation have been recorded. We suggest the current model as an additional appropriate tool for the investigation of spinal anesthesia.