ACVS Surgery STAT: Tips for reducing the pain of amputations in dogs
Amputation is a painful procedure, so aggressive, multimodal analgesia is necessary. The patient should receive a premedication that includes a pure mu agonist opioid such as morphine, fentanyl, oxymorphone or hydromorphone.
The epineurium of each nerve is injected, using a 25-22G needle. The nerve will swell characteristically when the injection is administered correctly and balloons out. The nerves are injected first and then the brachial artery and vein are ligated. After ligation, the block has taken effect and you can return to cutting the nerves. If they are blocked, the muscles should not twitch when the nerve is cut.Post-operative pain control and post-operative support are essential.
If there are no contraindications, a COX-1 sparing NSAID should be administered post-operatively. The patient also should be maintained on an opioid or intermittent doses of oxymorphone or hydromorphone every five to six hours.
Patients should be on intravenous fluids during surgery and post operatively at 1.5 times maintenance rates.
An in-dwelling urinary catheter and closed-collection system should be used for the first eight to 12 hours because these patients usually are nonambulatory immediately post operatively, allowing quantification of urine production and hydration status.
After the first 24 hours, patients can start on oral pain medications. A good combination is continuing the NSAID that was administered parentally, along with an opioid. The opioid can be oral tramadol or a fentanyl patch. If a fentanyl patch is used, it must be applied 12 to 24 hours before it is to be relied upon for analgesia.
Post-operative analgesia should be continued for five to seven days after the patient has gone home, depending on the pain level.
Dr. Boston is a board-certified ACVS small-animal surgeon. She completed her residency training at the University of Guelph and a post-doctoral fellowship in surgical oncology at Colorado State University. Her main area of interest is surgical oncology. Dr. Boston is currently a professor of small-animal surgery at the Ontario Veterinary College, University of Guelph.