Long-term epidural catheterization of rhesus macaques: loss of resistance technique

A method was developed for implantation of epidural catheters in the pregnant rhesus macaque (Macaca mulatta) for subsequent drug delivery in the fully conscious animal at parturition. Catheters were placed into the epidural space of 23 pregnant monkeys and accessed via a subcutaneously implanted vascular access port. The loss-of-resistance technique, a simple nonsurgical (percutaneous) technique, was used to locate the epidural space. Placement was confirmed at surgery by contrast radiography. There were no perioperative complications, and complications associated with long-term catheterization were limited.