腮腺手术与面神经功能损伤及术后恢复的关系

Correlation of parotidectomy with functional injury of facial nerve and postoperative recovery

目的:以神经电图和临床H-B系统方法联合评价腮腺良性肿瘤手术对面神经的损伤的程度;并按照手术方式、肿瘤大小、术中面神经暴露时间、面神经牵拉程度分组对照比较其与面神经损伤的关系;同时观察神经电图各相关指标在评价面神经损伤中的特定意义。方法:选择2001-07/2003-10山东聊城市人民医院收治的50例单侧型腮腺良性肿瘤患者。①使用神经肌电图机于术前12～24h及术后3,10,20,80,100d评价面神经功能状态,根据H-B评价体系的理论和方法观察面神经受损状况。②按照手术方式、肿瘤大小、术中面神经暴露时间、面神经牵拉程度分组,观察各组术后面神经损伤情况。③检测神经动作电位的波幅、潜伏时和电位持续时间并计算出神经损伤的变性率,以术前健侧结果作正常对照值,评价在面神经损伤中的意义。结果:①H-B系统显示术后3～20d为面神经麻痹的进展期,40d为面神经麻痹逆转的高峰期,60d后面神经麻痹恢复的机率明显减少。②腮腺全切、浅叶全切及功能性浅叶切除3种手术方式术后波幅值、潜伏时、改变程度依次减少。面神经功能减低程度随术中暴露时间增加而增高。③手术后3d起神经损伤的变性率、波幅值、潜伏时、动作电位持续时间均较正常水平有显著性改变,并在10d时达到高峰,20～40d神经功能开始逐渐明显恢复,60d后修复变化明显减少[术后3d变性率(47.20±14.35)%、波幅值(0.98±0.36)mV、潜伏时(6.33±1.58)ms、动作电位持续时间(9.55±1.82)ms,P<0.05或0.01]。结论:①腮腺良性肿瘤手术对面神经的损伤可恢复。面神经的损伤在术后10d表现最明显,20～40d为神经修复的活跃期,60d后为神经修复的缓慢期或静止期。②神经损伤程度随腮腺切除范围增加而增高,面神经解剖前提下的腮腺浅叶局限性切除最有利于保护面神经功能,面神经损伤与术中暴露时间、面神经牵拉程度等因素有直接关系。③动作电位持续时间、潜伏时的变化对反映早期严重的神经结构损害较敏感,神经损伤的变性率、波幅值主要显示原发性损伤后的神经失用水平以及变性与修复的转变过程。

AIM： To assess the injured degree of facial nerve injury caused by parotidectomy with electro-neurogram （ENoG） and H-B system; to compare the relationship with facial nerve injury according to operation method, size of tumor, intraoperative exposure time of facial nerve, extent of nerve stretching; and to observe the special and definite implications of the ENoG contents in evaluating the facial nerve injury. METHODS： A total of 50 patients with unilateral benign parotid gland tumors ware selected from Shandong Liaocheng People＇s Hospital between July 2001 and October 2003. ①Facial nerve function was assessed with ENoG methods at hours 12-24 before operation and at 3-, 10-, 20-, 80-, and 100-day postoperative intervals; Facial nerve injury was observed with H-B system. ②Postoperative injury of facial nerve was observed based on operation method, size of tumor, intraoperative exposure time of facial nerve, extent of nerve stretching. ③Amplitude （Am）, latency time （LT） and duration time （DT） of action potential ware measured. Meanwhile, degeneration rate （DR） of facial nerve was calculated. Result of preoperative uninjured side was used as normal control value. The significance of facial nerve injury was evaluated. RESULTS： ① H-B system showed that prosopoplegic progression was from day 3 to day 20 after operation; prosopoplegic reverse crest-time was at day 40; the probability of prosoplegia recovery markedly decreased from day 60. ②Postoperative Am, LT and changed degree reduced following parotidectomy, superficial lobe parotidectomy, functional superficial lobe parotidectomy. The decreased degree of facial nerve function increased with the increase of intraoperative exposure time. ③DR, Am, LT and DT of nerve injury distinctly changed as compared with the normal level from day 3 after operation and the summit change was at 10-day interval. The most evident recovery of the injured facial nerve was manifested from 20-day to 40-day interval, while a long period after 60 days witnessed the remarkable decreased potentials to recovery [DR at day 3 after operation（47.20±14.35）%, Am（0.98±0.36） mV, LT（6.33±1.58） ms, DT（9.55±1.82） ms, P〈 0.05 or 0.01]. CONCLUSION： ①Parotidectomy can recover the injury of facial nerve. The injury of facial nerve is the most obvious at day 10 after operation; the active phase of nerve repair are from 20-40 days; from 60-day it is the lag phase or stationary phase. ②The injured degree of facial nerve increases with the increase of removal range. The limited superfacial parotidectomy in addition to part d!ssection of facial nerve can conserve the nerve function in the largest measure. The injury of facial nerve has direct relation with intraoperative exposure time, extent of nerve stretching and so on. ③The changes of LT and DT are more sensitive to indicate the structural damages of facial nerve. DR and Am mainly represent the level of nerve apraxia as wall as the transition process of degeneration and repair.