Department of Veterinary Medicine, Centro Clinico Veterinario e Zootecnico Sperimentale, Università degli Studi di Milano, Milan, Italy.
Department of Veterinary Medicine, Università degli Studi di Milano, Milan, Italy.
Vet Anaesth Analg. 2021 May;48(3):442-450. doi: 10.1016/j.vaa.2020.10.009. Epub 2020 Dec 29.
To compare the peribulbar injectate distribution and probability of regional anaesthesia of four peribulbar anaesthetic techniques in equine cadavers.
Prospective experimental cadaver study.
A total of 12 isolated equine cadaver heads and 24 eyes.
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.
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.
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.
比较四种眼周麻醉技术在马属动物尸体中的球周注射剂分布和区域麻醉概率。
前瞻性实验尸体研究。
总共 12 个孤立的马属动物头颅和 24 只眼睛。
24 个眼眶接受了四种注射技术中的一种（每种技术 6 个眼眶），使用对比剂和生理盐水（CM）的混合物（1:4）：20 毫升外侧球周注射（V-20）、20 毫升外侧球周注射（D-20）、各 10 毫升的外侧和内侧球周联合注射（VD-20）或各 20 毫升的外侧和内侧球周联合注射（VD-40）。为了评估和评分 CM 在基底、眼外肌圆锥内（EOMC）和视神经周围的分布（在眶周区域施加压力前后），进行了计算机断层扫描。为了评估实现局部麻醉的概率，应用了两个标准，并将两者均评为“可能”、“可能”或“不可能”。为了比较注射技术之间的 CM 分布评分，使用了 Kruskal-Wallis 方差分析。当需要时，使用 Mann-Whitney U 检验进行组间的事后比较。p 值<0.05 被认为具有统计学意义。
在 24 个眼眶中的 7 个眼眶（V-20，3 个；D-20，1 个；VD-40，3 个）中，仅在施加压力后才能检测到 EOMC 内和视神经周围的 CM 分布为“可能”。在施加压力前后，它从未被认为是“可能”的。在 EOMC 基底处，50%（V-20）、0%（D-20）、33%（VD-20）、100%（VD-40）和 66%（V-20）、16%（D-20）、50%（VD-20）、100%（VD-40）的 CM 分布被认为提供了区域麻醉，分别在施加压力前后。
使用 VD-40 技术似乎更有可能实现完全的区域麻醉，尽管由于潜在并发症的风险，作者建议谨慎使用。需要进一步的研究来评估该技术在体内的疗效。
