Department of Anesthesia, Hospital de Clinicas, Universidad de la Republica, Montevideo, Uruguay.
Department of Anesthesiology and Pain Medicine, Toronto Western Hospital, University of Toronto, McL 2-405, TWH 399 Bathurst Street, Toronto, ON, Canada.
Can J Anaesth. 2020 Aug;67(8):942-948. doi: 10.1007/s12630-020-01613-8. Epub 2020 Mar 9.
Despite the popularity of the erector spinae plane (ESP) block, both the mechanism of the block and the extent of injectate spread is unclear. This study used magnetic resonance imaging (MRI) to evaluate the spread of local anesthetic injectate following ESP blocks in six patients with pain.
Six patients received a left-sided ultrasound-guided ESP block at the T10 level. The injectate contained 29.7 mL of 0.25% bupivacaine and 0.3 mL of gadolinium in the first patient, with an additional 5 mL (50 mg) of triamcinolone in the subsequent five patients. Sensory block to pinprick and cold as well as pain score (with 0 indicating no pain and 10 being maximum pain) were assessed 20 and 30 min respectively following the ESP block. MRI was performed one hour after the block.
The injectate spread into the intercostal space and neural foramina in all six patients, but the extent of cephalocaudal spread was variable, with a median [interquartile range] spread of 9 [5-11] and 3 [2-6] levels for the intercostal space and neural foramina, respectively. The injectate also spread extensively within the erector spinae muscles. Spread to the epidural space was seen in two patients. Sensory block was achieved in both ventral and dorsal dermatomes in all patients, though the extent was variable.
Our study showed that the ESP block injectate consistently spread to the erector spinae muscles, neural foramina, and intercostal space. It was associated with sensory changes and pain relief in the dorsal and ventral thoracic and abdominal walls. Nevertheless, the extent of spread to the neural foramina and intercostal space, and the sensory block itself, was highly variable.
尽管竖脊肌平面（ESP）阻滞术广受欢迎，但该阻滞术的机制和注射剂扩散范围仍不清楚。本研究使用磁共振成像（MRI）评估了 6 例疼痛患者接受超声引导下左侧 T10 水平 ESP 阻滞术时局部麻醉注射剂的扩散情况。
6 例患者接受了左侧超声引导下 ESP 阻滞术，第 1 例患者的注射剂中含有 29.7ml 0.25%布比卡因和 0.3ml 钆，随后 5 例患者分别额外加入 5ml（50mg）曲安奈德。ESP 阻滞后 20 分钟和 30 分钟分别评估针刺和冷觉感觉阻滞以及疼痛评分（0 表示无痛，10 表示剧痛）。ESP 阻滞后 1 小时进行 MRI 检查。
6 例患者的注射剂均扩散至肋间和神经孔，但头侧-尾侧扩散程度不同，肋间和神经孔的中位[四分位间距]扩散范围分别为 9[5-11]和 3[2-6]个节段。注射剂也在竖脊肌内广泛扩散。2 例患者的注射剂扩散至硬膜外腔。所有患者均在腹侧和背侧皮节获得感觉阻滞，但程度不同。
本研究表明，ESP 阻滞术的注射剂可稳定扩散至竖脊肌、神经孔和肋间，可引起胸腹壁背侧和腹侧的感觉变化和疼痛缓解。然而，神经孔和肋间的扩散程度以及感觉阻滞本身高度可变。
