超声引导耳大神经阻滞在鼓室乳突手术的临床应用与效果评价

目的 探索应用高频超声引导单独阻滞耳大神经的临床实践方法,并对耳大神经阻滞的临床效果进行评价.方法 60例鼓室乳突手术患者随机分为对照组(A组)与耳大神经阻滞组(B组),每组30例,2组均在全身麻醉下完成鼓室乳突手术.B组全麻诱导前应用超声引导平面内技术以0.25％罗哌卡因2 ml阻滞患侧耳大神经.注药后10 min,以针刺法测试耳部各分区阻滞效果.术后随访患者,以针刺法判断耳大神经阻滞消退时间,并记录患者术后24 h的VAS评分.结果 B组30例患者的耳大神经在超声下均可探查确认并成功阻滞.100％阻滞有效的区域为乳突区、耳廓背面、耳轮、耳轮尾、对耳屏、耳垂、下颌角,而耳轮脚、对耳轮、耳甲腔、耳屏、下颌缘、颊部、耳前区域则存在阻滞无效的可能.0.25％罗哌卡因2ml对耳大神经的阻滞时长为(11.70±1.95)h.术后0～12h,B组术后中重度疼痛(VAS≥4分)发生率明显低于A组(2例vs.20例,P＜0.01).结论 应用高频超声探头可以明确探查并成功阻滞耳大神经,耳大神经阻滞范围可以覆盖耳部绝大部分神经支配区.0.25％罗哌卡因2ml对耳大神经的阻滞时长为11.70±1.95 h.耳大神经阻滞可以缓解鼓室乳突手术患者的术后疼痛.

Practice and evaluation of ultrasound guidance in great auricular nerve block in tympanomastoid surgery

Objective To evaluate the effectiveness of ultrasound guidance in great auricular nerve (GAN) block.Methods Sixty patients scheduled to undergo tympanomastoid surgery were randomly assigned into group A and B (30 cases in each group,ASA Ⅰ ～ Ⅱ).All patients received general anesthesia.Patients in group B received GAN block using 0.25％ ropivacaine 2 ml under ultrasound guidance before general anesthesia induction.Sensory block was evaluated by pinprick testing in comparison with the contralateral area 10 min after the injection of ropivacaine.The duration of GAN block was also determined by pinprick testing of bilateral mandibular angle area.The postoperative pain scores evaluated by Visual Analog Scale (VAS) were also recorded.Results The GANs were successfully seen and blocked with ropivacaine in all 30 patients in group B.Mastoid area,dorsal auricle,helix,tail of helix,antitragus,lobule,mandibular angle were 100％ blocked in all cases whereas crus of helix,antihelix,cavity of conchae,tragus,mandibular border,buccal and preauriculary area couldn't be blocked in all cases.Duration of GAN block with 2 ml 0.25％ ropivacaine was (11.70± 1.95)h.The occurance rate of VAS scores≥4 in group B was statistically lower than that in group A in 0～12 h post operation (P＜ 0.01).Conclusion Great auricular nerve can be reliably imaged by ultrasound guidance and successfully blocked with a minor volume of local anesthetic.Most of all the innervation area can be blocked by great auricular nerve block.Duration of great auricular nerve block with 2 ml 0.25％ ropivacaine was (11.70± 1.95)h.Patients received great auricular nerve block can get a relief of postoperative pain.