Objective

To describe an ultrasound-guided lateral quadratus lumborum (LQL) block technique and the spread characteristics of lidocaine–dye injected in the LQL plane using a transversal (LQL-T) or a longitudinal (LQL-L) approach.

Study design

Experimental anatomic study.

Animals

A total of eight canine cadavers.

Methods

Bilateral ultrasound-guided injections in the fascial plane lateral to the quadratus lumborum muscle and medial to the thoracolumbar fascia (LQL plane) with the needle directed at the first lumbar (L1) transverse process were performed using lidocaine–dye (0.3 mL kg⁻¹). Anatomical dissection determined the dye distribution, sympathetic trunk staining and number of spinal nerves stained circumferentially >1 cm.

Results

The LQL fascial plane was ultrasonographically recognized in all cadavers and filled with lidocaine–dye in all eight cadavers with the LQL-T approach and in six with LQL-L. The injectate spread ventral to the lumbar transverse processes, around the quadratus lumborum muscle and dorsal to the transversalis fascia, affecting the ventral branches of the spinal nerves and the sympathetic trunk. A median (range) of 4 (3–5) and 3 (0–4) ventral branches of the thoracolumbar nerves were dyed with LQL-T and LQL-L approaches, respectively (p = 0.04). The most cranial nerve stained was the twelfth thoracic (T12) with the LQL-T approach and T13 with LQL-L, and the most caudal was L3 with both approaches. The incidence of sympathetic trunk staining was significantly higher using LQL-T (six injections) compared with LQL-L (one injection; p = 0.04). Dye was not observed in the lumbar plexus, epidural space or abdominal cavity.

Conclusions and clinical relevance

Ultrasound-guided LQL-T approach resulted in a more consistent spread toward the spinal nerves and sympathetic trunk compared with LQL-L approach. Further studies are necessary to assess the LQL block effectiveness and success rate in live dogs.

中文翻译：

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一种新型的超声引导下狗的外侧方方腰部阻滞：两种方法的比较尸体研究

目的

描述一种超声引导的侧方腰方（LQL）阻滞技术，以及使用横向（LQL-T）或纵向（LQL-L）方法在LQL平面内注射的利多卡因染料的扩散特性。

学习规划

实验性解剖学研究。

动物

共有八只犬尸。

方法

使用利多卡因-染料（0.3 mL kg ^-1），在四头肌腰部肌外侧的筋膜平面和胸腰部筋膜的内侧（LQL平面）的双侧超声引导下注射，针头指向第一个腰椎（L1）横向过程。）。解剖解剖确定了染料分布，交感神经干染色和在圆周上染色的脊髓神经数量> 1 cm。

结果

LQL筋膜平面在所有尸体中均得到了超声检查，并使用LQL-T方法在所有8具尸体中用利多卡因-染料填充，在LQL-L中用6填充了利多卡因染料。注射物从腹侧到腰椎横突，遍及腰方肌，背侧到横筋膜，影响脊髓神经和交感神经的腹侧分支。分别用LQL-T和LQL-L方法对胸腰神经的4个（3-5）和3（0-4）个腹侧支的中位（范围）进行染色（p = 0.04）。颅神经最多的是LQL-T入路的第十二胸椎（T12），LQL-L的是T13入路，两种入路的尾部最多均为L3。与LQL-L（一次注射；p  = 0.04）相比，LQL-T（六次注射）交感躯干染色的发生率明显更高。在腰丛，硬膜外腔或腹腔中未观察到染料。

结论与临床意义

与LQL-L方法相比，超声引导的LQL-T方法导致更均匀地向脊神经和交感神经干扩散。需要进一步的研究来评估活狗的LQL阻滞效果和成功率。