电刺激面神经麻痹兔眼轮匝肌诱发闭眼的刺激位点的选择

Comparative study of eyelid closure induced by electric exciting different sites on odoiculads oculi muscle

目的 利用电流直接刺激失神经支配的兔眼轮匝肌诱发闭眼反应,寻找能以最小刺激电流诱发有效闭眼的最佳刺激位点.方法 20只（40侧）新西兰兔,切断双侧面神经制备面神经麻痹模型.刺激电流为双电极、双向交流矩形方波,频率35 Hz,脉宽0.2 ms,电流强度可调.围绕眼轮匝肌,选取眶上缘中点（A）、眶外缘（B）、眶下缘中点（C）三个位点,分别以间距2.5 mm和5.0 mm的双电极进行刺激,再加上双电极分别置于A、B和A、C两种方式,共八种刺激模式,分别标识为A2.5、A5.0、B2.5、B5.0、C2.5、C5.0和AB、AC.以能使眼睑有效闭合的最小刺激电流值为阈电流值.结果 八种刺激方式阈电流值引出率用联组x2检验,差异有统计学意义,C2.5、C50和AC三种刺激方式,有效闭眼引出率低;其余五种方式的阈电流平均值进行ANOVA检验,差异有统计学意义（F =7.92,P＜0.001）.LSD检验,阈电流均值最低的B2.5与A2.5、AB相比,差异具有统计学意义（P值均＜0.001）,与A5.0、B5.0相比,差异无统计学意义（P值均＞0.05）;阈电流平均值第二低的A5.0与A2.5比较,差异有统计学意义（P＜0.05）.B2.5、B5.0和A5.0三种方式获得完美闭睑形态的比率最高.结论 电极置于眶上缘中点和眶外缘时可获得较高的有效闭眼率、较好的闭眼形态和较低的阈电流值,是应该优先采用的技术方案.

Objective Directly excited the denervated orbicularis oculi muscle （OOM） by electric current on rabbits,to induce efficient eyelid closure,and seek the optimal sites for such excitation that can produce efficient eyelid closure with the minimal excitating current in the least channel.Methods Bilateral peripheral facial paralysis model on 20 healthy NewZealand rabbits （40 sides）were prepared.Exciting current was designed for two-way rectangular pulse,35 Hz frequency and 0.2ms pulse width.The current intensity could be adjusted between 0 and 2.5 mA.Middle of upper-orbit （A）,outer orbital rim （B）,and middle of lower-orbit （C） sites were located around the OOM.Each site underwent parallel muscle fiber excitation by 2.5 and 5 mm distance dual-electrode respectively,additional dual-electrodes were also placed in A-B and A-C positions.All resulted in a total of 8 different exciting methods,and were labeled A2.5,A5.0,B2.5,B5.0,C2.5,C5.0,AB and AC.Then the current was adjusted to achieve efficient eyelid closure.The minimal current intensity needed was regarded as threshold value.Results All efficient eyelid closure occurrence rates of 8 methods were compared with combined x2 test and showed significant difference.A crossed x2 test showed the rates of C2.5,C5.0,and AC was significant lower than the highest methods.Except 3 methods above,the mean threshold values of remain 5 methods were compared with ANOVA test and showed significant difference.Further Fisher＇s LSD test showed B2.5 had the lowest mean value,was significant lower than A2.5 and AB,P ＜ 0.001,and had no significant difference with A5.0 and B5.0,P ＞ 0.05.A5.0＇s mean value was significant lower than A2.5 ＇s,P ＜ 0.05.Methods B2.5,B5.0 and A5.0 were more likely to achieve a perfect closure.Conclusions Middle of supraorbital margin （A） and outer orbital rim （B） are the ideal sites for electric excitation.Exciting the two sites can sufficiently induce the contraction of denervated OOM,leading to high efficient eyelid closure occurrence rates,more perfect closure meanwhile with lower threshold current value,which are priority options.