Evaluation of the analgesic efficacy of Yamamoto new scalp acupuncture method in castrated dogs

This study aimed to investigate the analgesic efficacy of Yamamoto New Scalp Acupuncture (YNSA) in managing postoperative pain in castrated dogs. Twenty healthy dogs aged (mean ± standard deviation) 22 ± 12 months and weighing 29 ± 7 kg were randomly assigned to either the YNSA or control group (n = 10 per group). Acupuncture was performed 20 minutes before anesthesia induction and continued throughout the surgery using basic B, C, and D acupuncture points. Acute pain was assessed at baseline (T0), 0.5 (T0.5), 1 (T1), 2 (T2), 4 (T4), 6 (T6), 8 (T8), 12 (T12), 16 (T16), 20 (T20), and 24 (T24) hours postoperatively using the Glasgow Acute Pain Scale-Short Form (CMPS-SF) and the Colorado State University Canine Acute Pain Scale (CSU-CAP). Salivary cortisol levels were measured at T0, T0.5, T2, and T24. Postoperative rescue analgesia requirements and fentanyl doses were recorded. The YNSA group showed a significantly shorter time to return of appetite compared to the control group (p = 0.036), as well as significantly lower CMPS-SF scores at T0.5 (p <0.001), and CSU-CAP scores at T0.5 (p <0.001), T16 (p = 0.029), T20 (p = 0.029), and T24 (p = 0.029) postoperatively. The YNSA group required significantly fewer rescue analgesia interventions (1 dog versus 10 dogs, p = 0.002) and significantly fewer fentanyl doses (1 dose versus 12 doses, p <0.001). While salivary cortisol levels did not show a statistically significant difference, the overall decreasing trend observed in the YNSA group suggests a potential stress-reducing effect. In conclusion, perioperative YNSA resulted in reduced pain scores and decreased postoperative rescue analgesia requirements in dogs. These findings support the use of YNSA as an effective adjunct to multimodal analgesic protocols for managing postoperative pain in castrared dogs.