Barczyński Marcin, Stopa Małgorzata, Konturek Aleksander, Nowak Wojciech
Department of Endocrine Surgery, Third Chair of General Surgery, Jagiellonian University Medical College, 37 Prądnicka Street, 31-202, Kraków, Poland.
Third Chair and Department of General Surgery, Jagiellonian University Medical College, 37 Prądnicka Street, 31-202, Kraków, Poland.
World J Surg. 2016 Mar;40(3):629-35. doi: 10.1007/s00268-015-3257-4.
Few small studies reported that motor fibers are located exclusively in the anterior branch of the bifid recurrent laryngeal nerve (RLN). The aim of this study was to investigate the location of the motor fibers to the intrinsic muscles of the larynx among the bifid RLNs, and assess the prevalence of RLN injury with respect to nerve branching in a pragmatic trial.
This was a prospective cohort study of 1250 patients who underwent total thyroidectomy with intraoperative neural monitoring. The primary outcome was the position of the motor fibers in the bifid nerves. Adduction of the vocal folds was detected by the endotracheal tube electromyography and abduction by finger palpation of muscle contraction in the posterior cricoarytenoid. The secondary outcomes were the prevalence of the RLN branching and the prevalence of RLN injury in bifid versus non-bifid nerves.
The bifid RLNs were identified in 613/2500 (24.5%) nerves at risk, including 92 (7.4%) patients with bilateral bifurcations. The motor fibers were present exclusively in the anterior branch in 605/613 (98.7%) bifid nerves, and in both the RLN branches in 8/613 (1.3%) bifid nerves. Prevalence of RLN injury was 5.2 versus 1.6% for the bifid versus non-bifid nerves (p < 0.001), odds ratio 2.98 (95% confidence interval 1.79-4.95; p < 0.001).
The motor fibers of the RLN are located in the anterior extralaryngeal branch in the vast majority of but not in all patients. In rare cases, the motor fibers for adduction or abduction are located in the posterior branch of the RLN. As the bifid nerves are more prone to injury than non-branched nerves, meticulous dissection is recommended to assure preservation of all the branches of the RLN during thyroidectomy.
少数小型研究报道运动纤维仅位于双分支喉返神经（RLN）的前支。本研究的目的是调查双分支RLN中支配喉内肌的运动纤维的位置，并在一项实用性试验中评估RLN损伤相对于神经分支的发生率。
这是一项对1250例行全甲状腺切除术并术中进行神经监测的患者的前瞻性队列研究。主要结局是双分支神经中运动纤维的位置。通过气管插管肌电图检测声带内收，通过手指触诊环杓后肌收缩检测外展。次要结局是RLN分支的发生率以及双分支与非双分支神经中RLN损伤的发生率。
在2500条有风险的神经中，识别出613条（24.5%）双分支RLN，其中92例（7.4%）为双侧分支。在613条双分支神经中，605条（98.7%）的运动纤维仅存在于前支，8条（1.3%）的运动纤维存在于RLN的两个分支中。双分支神经与非双分支神经的RLN损伤发生率分别为5.2%和1.6%（p<0.001），比值比为2.98（95%置信区间1.79 - 4.95；p<0.001）。
绝大多数但并非所有患者的RLN运动纤维位于喉外前支。在极少数情况下，内收或外展的运动纤维位于RLN的后支。由于双分支神经比非分支神经更容易受损，因此建议在甲状腺切除术中进行细致解剖，以确保保留RLN的所有分支。
