Introduction

Lumbosacral approach has been used for rabbit epidural anesthesia (Hughes et al. 1993). However, the technique was reported to cause intrathecal injection in all studied rabbits (Otero et al. 2012).

Objectives

To evaluate the effects of lidocaine injected into the epidural space via intercoccygeal site percutaneously in rabbits.

Methods

Under general anesthesia with isoflurane following propofol induction, rabbits were placed in ventral recumbency with elevated hip. A 27-gauge spinal needle was inserted percutaneously at dorsal tail base in caudocranial direction. Correct needle placement in the epidural space was confirmed by contrast radiography using iohexol (0.05–0.1 ml/kg). Then, either 0.3 ml/kg of lidocaine 2% (n=4) or normal saline (NS) (n=4) was injected randomly in blinded fashion. Pulse rate and blood pressure (non-invasive monitoring) were recorded before and after the injection. One minute after the injection, general anesthesia was discontinued. Neurological examination was performed in blinded fashion before and every 20 minutes after general anesthesia until all findings back to normal; and reassessed one week later.

Results

Lidocaine group has significant longer recovery time to normal anal tone, gait, conscious proprioception (CP), and deep pain perception (DPP) of hindlimbs, compared to NS group. No difference was observed for the recovery time of mentation and forelimbs’ CP and DPP between two groups. Blood pressure significantly decreased after lidocaine injection, but not changed after NS injection. No complications were observed during the one week follow-up period.

Conclusions

Percutaneous lidocaine injection technique into the epidural space via intercoccygeal site may be used for rabbit hindlimb anesthesia.