Another study compared scalpel and guillotine methods retrospectively by using observational data from students.26 This study is difficult to interpret because multiple students performed the surgeries and recorded the observations.26 Additionally, the closure method was not controlled in the comparison.26 Although specific technique in the hands of an experienced surgeon may not cause more pain than another technique, inexperienced
surgeons may cause more trauma to surrounding tissues and cause more pain with any technique. Regardless of the technique
or skill level, the patient should receive perioperative and postoperative analgesia.
PAIN MANAGEMENT OPTIONS
Table 1. Common Drugs and Dosages for Perioperative Analgesics for Feline Onychectomy
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Several different classes of drugs are used for perioperative analgesia in cats undergoing onychectomy. Opioids, local anesthetics,
nonsteroidal anti-inflammatory drugs (NSAIDs), and α2-agonists have all been used in cats with some benefit. N-Methyl-D-aspartate antagonists, such as ketamine, are often used for anesthesia in cats, but specific studies on the analgesic
effects postoperatively are not available. Table 1 summarizes some of the most common analgesics used perioperatively. Choosing an analgesic protocol may be confusing because
of the multiple advantages and disadvantages of each drug. The duration of action, dosage, cost, side effects, and method
of administration vary for all analgesics. Ideally, the protocol should be tailored to the individual patient, and multimodal
therapy is likely the most beneficial.
Opioids
In general, opioids inhibit neurotransmitters centrally. Opioids are further classified as partial or full agonists or antagonists
of the µ or k receptors.8,9 Side effects of opioids include bradycardia, vomiting, respiratory depression, decreased gastrointestinal motility, and dysphoria.8,9 Although µ-receptor agonists are accompanied by more side effects, they provide more profound analgesia. The more commonly
used µ agonists in veterinary medicine include hydromorphone, oxymorphone hydrochloride, morphine, and fentanyl citrate. Kappa
agonists such as butorphanol, which also has µ antagonistic effects, are associated with less cardiac or respiratory depression
or gastrointestinal upset than µ agonists.8,9 Sedation may still occur. Intravenous, intramuscular, or subcutaneous administration typically produces consistent systemic
drug concentrations; however, transdermal and oral treatment with opioids produces more variable results in cats.7-11,19,27,28
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