Objective

To compare the peribulbar injectate distribution and probability of regional anaesthesia of four peribulbar anaesthetic techniques in equine cadavers.

Study design

Prospective experimental cadaver study.

Animals

A total of 12 isolated equine cadaver heads and 24 eyes.

Methods

The 24 orbits underwent one of four injection techniques (six orbits each) with a mixture (1:4) of contrast medium and saline (CM): 20 mL ventrolateral peribulbar injection (V-20), 20 mL dorsolateral peribulbar injection (D-20), combined ventrolateral and dorsolateral peribulbar injections 10 mL each (VD-20) or 20 mL each (VD-40). To evaluate and score CM distribution at the base of, within the extraocular muscle cone (EOMC), and around the optic nerve (before and after pressure application to the periorbital area), computed tomography was performed. To assess the probability of achieving locoregional anaesthesia, two criteria were applied and both scored as ‘likely’, ‘possible’ or ‘unlikely’. To compare CM distribution scores between injection techniques, Kruskal-Wallis analysis of variance was used. Mann-Whitney U test was used for post hoc comparisons between groups when needed. A p value < 0.05 was considered significant.

Results

The CM distribution within the EOMC and around the optic nerve circumference was detected as ‘possible’ only after pressure application in seven out of 24 orbits (V-20, 3; D-20, 1; VD-40, 3). It was never considered ‘likely’ either before or after pressure application. The CM distribution at the EOMC base was considered ‘likely’ to provide regional anaesthesia in 50% (V-20), 0% (D-20), 33% (VD-20), 100% (VD-40) and in 66% (V-20), 16% (D-20), 50% (VD-20), 100% (VD-40) before and after applying pressure, respectively.

Conclusions and clinical relevance

Complete regional anaesthesia seems more likely using the VD-40 technique, although the authors advise caution due to the risk of potential complications. Future studies are necessary to evaluate the efficacy of the technique in vivo.

中文翻译：

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四种球周麻醉技术的比较：马尸体的初步研究

客观的

比较四种球周麻醉技术在马尸体上的球周注射分布和区域麻醉的概率。

学习规划

前瞻性实验尸体研究。

动物

共有 12 个孤立的马尸体头部和 24 只眼睛。

方法

24 个眼眶接受了四种注射技术中的一种（每个 6 个眼眶），使用对比剂和生理盐水 (CM) 的混合物 (1:4)：20 mL 腹外侧球周注射 (V-20)，20 mL 背外侧球周注射 (D- 20)，联合腹外侧和背外侧球周注射，各 10 mL (VD-20) 或 20 mL (VD-40)。为了评估和评分眼外肌锥 (EOMC) 底部、眼外肌锥 (EOMC) 内和视神经周围的 CM 分布（向眶周区域施加压力之前和之后），进行了计算机断层扫描。为了评估实现局部麻醉的可能性，应用了两个标准，并且都被评分为“可能”、“可能”或“不太可能”。为了比较注射技术之间的 CM 分布得分，使用了 Kruskal-Wallis 方差分析。曼-惠特尼ü当需要时，检验用于组间的事后比较。甲p值<0.05被认为显著。

结果

仅在 24 个轨道中的 7 个（V-20, 3; D-20, 1; VD-40, 3）施加压力后，EOMC 内和视神经周围的 CM 分布才被检测为“可能”。在施加压力之前或之后，它从未被认为是“可能的”。EOMC 基地的 CM 分布被认为“可能”在 50% (V-20)、0% (D-20)、33% (VD-20)、100% (VD-40) 和施压前后分别为 66% (V-20)、16% (D-20)、50% (VD-20)、100% (VD-40)。

结论和临床相关性

使用 VD-40 技术进行完全区域麻醉的可能性更大，但作者建议谨慎行事，因为存在潜在并发症的风险。未来的研究是必要的，以评估该技术在体内的功效。