經皮肝腫瘤射頻消融術的區域麻醉及疼痛管理

在小型肝腫瘤的消融療法中，經皮肝腫瘤射頻消融術被建議為治療首選且已被廣泛的應用在臨床。近來由於其優異的療效及對於多重共病症的病人具有相對較小的侵入性，治療的標的更擴及到較大或者是多發性肝腫瘤。此外，消融的方式也從腫瘤內熱療進化到腫瘤旁來避免針尖置於腫瘤中熱療時引起腫瘤爆出至正常肝組織的現象。上述這些有關於經皮肝腫瘤射頻消融術在目標以及治療方法上的進化使得病人常常需要同時使用多支且因同軸心調節溫度而較粗的針體來達成消融的目標，而這樣的背景組合對於鎮靜麻醉產生了挑戰。

區域神經阻斷對於經皮肝腫瘤射頻消融術中的穩定以及術後恢復佔有重要角色。了解肝臟以及其相關組織的神經支配以及經皮肝腫瘤射頻消融術可能在術中產生的併發症有助於圍術期的處理。遵從人體工適學並應用無菌姿勢可以使得相對應區域的胸椎旁神經阻斷術變得較容易執行且在超音波導引下具有可視性注射前後指標。難治型肩部牽涉痛雖然不常見但可能發生於經皮肝腫瘤射頻消融術在熱療時所引起的橫膈膜刺激，在麻醉恢復室可能需要膈神經阻斷來提供適當的止痛。在這種情況下，我們建議在上神經幹高度從前斜角肌平面入針的方式同時合併超音波及改良版的雙管壓力設置來避免相關的併發症，包括若在橫膈高度進行膈神經阻斷所產生的不完全止痛，非預期的筋膜外其他頸部神經的阻斷，以及神經受損(針尖引起的機械性創傷、神經束內注射、膈神經所在空間壓力上升所引起的神經失用症等等)的最重要考量。

Regional Anesthesia and Pain Management for Percutaneous Radiofrequency Ablation of Liver Tumors

Percutaneous radiofrequency ablation (PRFA) of liver tumors has gained its popularity since it was recommended as the main ablative treatment for tumors less than 5 cm. Recently, the targets for liver PRFA underwent a transition from smaller toward larger and multiple lesions due to effectiveness and less invasiveness for patients with multiple comorbidities. Moreover, the technique also underwent a transition from intra-tumoral toward no-touch lesioning to prevent popcorn effect. Therefore, multiple co-axial needles at the same time are required to accomplish the missions, which challenges the perioperative management when it is performed under monitored anesthesia care. 

Regional blocks are of utmost importance for stable maintenance during the ablative procedure as well as patient recovery. Knowledge of peri-hepatic innervation and adverse events caused by liver PRFA facilitates perioperative management. Abiding by physical ergonomics in the aseptic position, thoracic paravertebral block for corresponding innervation areas can be more easily carried out with visible ultrasound endpoints. Intractable referred shoulder pain following diaphragm irritation, uncommon but may happen, possibly requires phrenic nerve block to achieve adequate pain relief in the postoperative care unit. Under such circumstances, we recommend anterior scalene plane approach at the level of superior trunk with both ultrasound guidance and modified half-the-air setting to avoid potential complications such as incomplete analgesia when blocking it at the diaphragm level, unwanted extra-fascial spread, and, above all, nerve injury secondary to mechanical needle trauma, intra-fascicular injection as well as pressure-induced neuropraxia.