Objective

To evaluate the efficacy, duration and safety of greater auricular and auriculotemporal nerve blocks in rabbits.

Study design

Prospective, randomized, crossover, experimental study.

Animals

A total of 11 healthy adult Dutch-belted rabbits.

Methods

The rabbits underwent general anesthesia and injections of the greater auricular and auriculotemporal nerves using either bupivacaine (0.3 mL kg^–1, 0.5%) or the same volume of saline. After anesthesia, the efficacy and duration of nerve blocks were assessed using analgesiometry forceps on the pinna and cotton-tipped applicators within the vertical ear canal. Rabbits were monitored for abnormal carriage of the ear and auriculopalpebral nerve block of the ipsilateral eye. Body weight, food intake, fecal output and fecal pellet diameter were measured daily for 6 days after the nerve blocks were performed and compared with baseline to assess short-term effects.

Results

The greater auricular nerve was successfully blocked in 12/16 (75%) ears for mean ± standard deviation duration of 88 ± 52 minutes. In successfully blocked ears, altered ear position was noted in five/16 (31%) cases. The auriculotemporal nerve was blocked in one/16 ears for 120 minutes. The auriculopalpebral nerve was inadvertently blocked in three/16 ears. Food intake and fecal output decreased significantly during the treatment day but returned to pretreatment values after 24 hours. There was no change in body weight or fecal pellet diameter for either treatment.

Conclusions and clinical relevance

The results suggest that duration of the greater auricular nerve block with 0.5% bupivacaine was short-lived in the live rabbit. Auriculotemporal nerve block was only achieved in one ear; therefore, further studies are warranted to evaluate the contribution of these blocks in the pain management of rabbits undergoing auricular surgery.

中文翻译：

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在兔中执行较大的耳廓和耳颞神经阻滞的功效。

目的

评估兔耳廓和耳颞神经阻滞的疗效，持续时间和安全性。

学习规划

前瞻性，随机，交叉，实验研究。

动物

共有11只健康的成年荷兰带状兔。

方法

对兔子进行全身麻醉，并用布比卡因（0.3 mL kg ^–1，0.5％）或等量的生理盐水注射较大的耳和耳颞神经。麻醉后，使用垂直耳道内耳廓上的止痛钳和棉签涂药，评估神经阻滞的疗效和持续时间。监测兔子耳朵和同侧眼的耳睑神经神经传导异常。在进行神经阻滞后的6天内每天测量体重，食物摄入量，粪便排出量和粪便颗粒直径，并与基线进行比较以评估短期效果。

结果

在12/16（75％）的耳朵中成功阻塞了较大的耳神经，其平均±标准差持续时间为88±52分钟。在成功阻塞的耳朵中，有五分之十六（31％）的病例发现耳朵位置发生了改变。耳颞神经在1/16耳中阻塞120分钟。三/ 16耳无意中阻塞了耳睑神经。在治疗期间，食物摄入量和粪便排出量显着下降，但在24小时后恢复到治疗前的水平。两种治疗的体重或粪便颗粒直径均无变化。

结论与临床意义

结果表明，在活兔中，含0.5％布比卡因的大耳神经阻滞持续时间短。耳颞神经阻滞仅在一只耳朵中完成；因此，有必要进行进一步的研究来评估这些阻滞在耳科手术兔子的疼痛管理中的作用。