6. Summary
The objective of this study was to assess the efficacy of PG as an adjunctive pain medication in dogs suffering from mixed pain, including neuropathic pain after IVDD surgery.
Fifty-four client-owned dogs with thoracolumbar IVDD as well as seven dogs with cervical IVDD were initially assessed for this study. Application of either PG or a placebo was started in both treatment groups 30 minutes to 1 hour before anaesthesia. Treatment was continued every 8 hours over 5 days following surgery. The efficacy of PG as supplementary analgesia was evaluated with a VAS, the canine Colorado State University pain scale, and the short form of the Glasgow composite measure pain scale. In this particular pain scale the category gait was excluded.
Furthermore, algometer data for assessment of mechanical nociceptive threshold in the area of the surgery site were collected. Minimum serum concentrations were measured between two applications. Dogs pre-treated with pain medication or antiepileptics were excluded except for those treated with NSAIDs or corticosteroids. Dogs that had to undergo a reoperation within 5 days of initial surgery, dogs that underwent a second magnetic resonance diagnostic due to lack of improvement, or dogs that were euthanized within 5 days were excluded. Consequently, 46 dogs (aged 5.7 ± 2.5 years and weighing 12.7 ± 9.1 kg) were evaluated.
68 A standardized anaesthesia protocol was used in this study. All dogs were pre-medicated with levomethadone and diazepam. Induction was achieved by propofol followed by maintenance with isoflurane. Opioid analgesia after surgery consisted of a transdermal fentanyl patch applied directly after extubation and levomethadone until expected full effect of the fentanyl patch.
Statistical analysis was performed using mixed models and t-test.
PG as supplementary analgesia (4 mg/kg) after IVD surgery in dogs resulted in significantly less postoperative pain behavior compared to the control group. No major side effects were detected.
Minimum levels of serum PG were above the detection limit in the majority of dogs at both measurement points. Further studies to compare the efficacy of PG to its predecessor gabapentin and evaluation of different dosing regimes of PG are warranted.
69
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