以豬隻模式探討電生理監測與喉返神經受熱損傷之相關性

Electrophysiologic monitoring correlates of recurrent laryngeal nerve heat thermal injury in a porcine model

林逸筑(Yi-Chu Lin)

指導教授 ： 江豐裕

高雄醫學大學/醫學院/臨床醫學研究所/碩士(2015年)

摘要

背景：
溫度傷害(thermal injury)是甲狀腺手術中喉返神經受傷常見的機轉之一。此熱傷害通常是無形的且容易在術中被忽略。本實驗主要探討喉返神經的溫度耐受性(thermal tolerance)，並且藉由使用連續性術中監測評估喉返神經熱損傷時之肌電圖表現。
方法：
本實驗採用十隻迷你豬(n= 20條喉返神經)進行研究。術中神經監測採用迷走神經自動周期性刺激(automated periodic stimulation)；所誘發的聲門肌肌電圖經由氣管內管表面電極接收，同時連續性紀錄神經受到不同溫度之生理食鹽水沖洗時所對應之肌電圖訊號變化。
結果：
在此試驗性研究(n=4)中發現，以逐漸增溫(40/45/50/55℃)之生理食鹽水沖洗喉返神經60秒之過程中，肌電圖訊號均維持穩定；但當水溫升至60℃時，肌電圖出現快速的訊號喪失(n=4)。另16條喉返神經用於進一步深入探討及比較神經受到固定溫度但暴露於不同時間(60/70℃，20/30秒) (各n=4)之熱損傷時肌電圖的表現。研究發現肌電圖訊號在以60℃和70℃熱水沖洗時呈現快速訊號喪失，且所有受損之神經呈第一型節段性(segmental “type 1”)之病灶。八條以60℃熱水傷害之喉返神經有6條出現部分訊號恢復(16–35%)，但所有以70℃傷害之神經皆無恢復情形。所有神經訊號喪失點雖肉眼不可見但卻能以神經偵測儀探查。
結論：
本研究顯示60℃是喉返神經熱損傷之臨界溫度。術中神經監測可用於早期偵測及評估急性熱損害情形，並指導甲狀腺手術中與能量裝置(energy-based devices)相關或熱能治療之應用。

關鍵字

喉返神經 ； 連續性術中神經監測儀 ； 甲狀腺手術 ； 神經熱損傷 ； 能量裝置

並列摘要

Objective:
Thermal injury to the recurrent laryngeal nerve (RLN) may not be visually apparent and may go unrecognized intraoperatively. This study aimed to investigate the heat thermal tolerance of RLN and evaluate the electrophysiologic correlates of electromyographic (EMG) signal change during an acute RLN heat damage.
Study Design and Methods:
Prospective porcine model with continuous intraoperative neuromonitoring (CIONM). Ten pigs (20 RLNs) undergoing CIONM had their EMG tracings recorded and correlated with heated normal saline (NS) irrigation of varying temperature and duration.
Results:
In the initial pilot study, the EMG was without change during incremental heated NS irrigation (40/45/50/55℃ for 60 seconds), but adverse EMG combined events (CE) (amplitude decrease with a concordant latency increase) occurred and degraded to loss of signal (LOS) (by 17.5±1.3 seconds) when the temperature was elevated to 60℃ (n=4). Another 16 RLNs were evaluated to further compare the EMG pattern after various degrees of thermal stress (60/70℃ for 30/20 seconds). EMG recordings showed CEs and LOS in all RLNs, and only six of eight RLNs with 60℃ exposure showed slight EMG amplitude recovery (16%–35%) after 20 minutes. None of the injured nerve segments were visually apparent but all were detectable by IONM.
Conclusion:
Sixty degrees Celsius is a critical temperature to cause RLN thermal injury. CIONM can be used as a tool for the early detection of acute thermal stress and may guide use of energy-based devices during thyroid procedures.

並列關鍵字

Recurrent laryngeal nerve ； continuous intraoperative neuromonitoring ； thyroid surgery ； nerve thermal injury ； energy-based devices

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