Background

Image-guided procedures for treatment of liver diseases can be painful and require heavy sedation of the patient. Local-regional nerve blocks improve pain control and reduce oversedation risks, but there are no documented liver-specific nerve blocks.

Purpose

To develop a safe and technically simple liver-specific nerve block.

Materials and Methods

Between March 2017 and October 2019, three cadavers were dissected to evaluate the hepatic hilar anatomy. The hepatic hilar nerves were targeted with transhepatic placement of a needle adjacent to the main portal vein, under US guidance, and evaluated with use of an injection of methylene blue. A hepatic nerve block, using similar technique and 0.25% bupivacaine, was offered to patients undergoing liver tumoral ablation. In a prospective pilot study, 12 patients who received the nerve block were compared with a control group regarding complications, safety, pain scores, and intraoperative opioid requirement. Student t tests were used to compare the groups’ characteristics, and Mann-Whitney U tests were used for the measured outcomes.

Results

Cadaver results confirmed that the hepatic nerves coursing in the hepatic hilum can be targeted with US for injection of anesthetic agents, with adequate spread of injected methylene blue around the nerves in the hepatic hilar perivascular space. The 12 participants (mean age ± standard deviation, 66 years ± 13; eight men) who received a hepatic hilar block before liver thermal ablations demonstrated reduced pain compared with a control group of 12 participants (mean age, 63 years ± 15; eight men) who received only intravenous sedation. Participants who received the nerve block had a lower mean visual analog scale score for pain than the control group (3.9 ± 2.4 vs 7.0 ± 2.8, respectively; P = .01) and decreased need for intraprocedural fentanyl (mean dose, 152 μg ± 78.0 vs 235.4 μg ± 58.2, respectively; P = .01). No major complications occurred in the hepatic hilar nerve block group.

Conclusion

A dedicated hepatic hilar nerve block with 0.25% bupivacaine can be safely performed to provide anesthesia during liver tumoral ablation.

© RSNA, 2021

中文翻译：

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用于肝介入的肝门神经阻滞：肝脏肿瘤热消融的解剖学、技术和初步临床经验

背景

用于治疗肝脏疾病的图像引导程序可能会很痛苦，并且需要对患者进行大量镇静。局部神经阻滞可改善疼痛控制并降低过度镇静的风险，但没有记录在案的肝脏特异性神经阻滞。

目的

开发一种安全且技术上简单的肝脏特异性神经阻滞。

材料和方法

2017 年 3 月至 2019 年 10 月期间，解剖了三具尸体以评估肝门解剖结构。在 US 引导下，通过肝穿刺放置一根针靠近主门静脉，靶向肝门神经，并使用亚甲蓝注射进行评估。使用类似技术和 0.25% 布比卡因为接受肝脏肿瘤消融术的患者提供肝神经阻滞。在一项前瞻性试验研究中，12 名接受神经阻滞的患者与对照组在并发症、安全性、疼痛评分和术中阿片类药物需求方面进行了比较。Student t检验用于比较各组的特征，Mann-Whitney U检验用于测量结果。

结果

尸体结果证实，在肝门中的肝神经可以通过超声靶向注射麻醉剂，注射的亚甲蓝在肝门血管周围空间的神经周围充分扩散。在肝脏热消融术前接受肝门阻滞的 12 名参与者（平均年龄 ± 标准差，66 岁 ± 13 岁；8 名男性）与对照组 12 名参与者（平均年龄，63 岁 ± 15 岁；8 名男性）相比疼痛减轻) 只接受静脉镇静。接受神经阻滞的参与者疼痛的平均视觉模拟量表评分低于对照组（分别为 3.9 ± 2.4 和 7.0 ± 2.8；P = .01），并且对术中芬太尼的需求减少（平均剂量，152 μg ± 78.0分别与 235.4 μg ± 58.2 相比；P = .01）。肝门神经阻滞组未发生严重并发症。

结论

在肝脏肿瘤消融过程中，可以安全地使用含有 0.25% 布比卡因的专用肝门神经阻滞来提供麻醉。

©北美放射学会，2021