Objective

To develop a technique for ultrasound-guided continuous median and ulnar peripheral nerve block in horses.

Study design

Anatomical and prospective experimental study.

Animals

A total of 16 thoracic limbs from horse cadavers and 18 adult horses.

Method

This study was conducted in three phases. Phase 1: Dissection of median and ulnar nerves in the antebrachial region of two cadaver limbs to identify localizing landmarks. Description of sonoanatomy in 14 cadaver limbs using ultrasound-guided perineural infiltration of a combination of cellulose gel (5 mL), contrast medium (4 mL) and methylene blue (1 mL). Catheters were inserted between the perineural sheath and epineurium in six limbs, followed by computed tomography. Phase 2: Ultrasonographic images of the limbs of 18 healthy horses of different breeds were used to define an acoustic window and optimize the approach to nerves. Phase 3: Two case reports of horses with chronic pain of different etiologies. Catheters were inserted between the epineurium and paraneural sheath of the median and/or ulnar nerves guided by ultrasound, followed by continuous infusion of 0.4% ropivacaine.

Results

Information from phase 1 was used to direct needle insertion, solution dispersion and catheter implantation in phase 2, which resulted in 100% technique accuracy. In response to the peripheral nerve block, pain reduction was apparent in the two clinical cases by increased weight bearing in affected limbs and decreased requirement for systemic analgesic medications. No local reactions were observed.

Conclusions and clinical relevance

The ultrasound technique allowed real-time visualization of needle, catheter and drug dispersion and resulted in a high success rate for nerve blocks. The horses administered a median and ulnar nerve block exhibited no discomfort or signs of infection at the catheter insertion site. Further studies are warranted to validate the efficacy of this technique.

中文翻译：

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超声引导马的正中和尺神经的连续阻滞：该技术的发展。

目的

开发一种超声引导马连续中正和尺骨周围神经阻滞的技术。

学习规划

解剖和前瞻性实验研究。

动物

来自马尸体和18只成年马的总共16条胸肢。

方法

这项研究分三个阶段进行。阶段1：解剖两个尸体肢体前臂区的正中神经和尺神经，以识别局部标志。使用纤维素凝胶（5 mL），造影剂（4 mL）和亚甲蓝（1 mL）的组合进行超声引导的神经周围浸润对14个尸体肢体进行声纳解剖学的描述。将导管插入六个肢体的神经鞘膜和神经外膜之间，然后进行计算机断层扫描。阶段2：使用18种不同品种的健康马的四肢超声图像来定义声窗并优化神经接触方法。阶段3：有两个病因不同的慢性疼痛马匹的两个病例报告。在超声引导下，将导管插入到中神经和/或尺神经的神经外膜和神经外鞘之间，

结果

来自阶段1的信息用于指导阶段2中的针头插入，溶液分散和导管植入，这导致100％的技术准确性。在对周围神经阻滞的反应中，在两个临床病例中，通过增加患肢的负重和减少全身镇痛药物的需求，疼痛明显减轻。没有观察到局部反应。

结论与临床意义

超声技术可以实时观察针头，导管和药物的分散情况，从而使神经阻滞的成功率很高。给予正中和尺神经阻滞的马在导管插入部位未显示不适或感染迹象。有必要进行进一步的研究以验证该技术的有效性。