Department of Surgery, Tulane University, School of Medicine, New Orleans, LA.
Surgery. 2011 Jun;149(6):820-4. doi: 10.1016/j.surg.2011.02.012. Epub 2011 Apr 17.
Recognition of extralaryngeal branching of the recurrent laryngeal nerve (RLN) is crucial, because inadvertent operative division may lead to significant postoperative morbidity. The purpose of this study was to examine the incidence of extralaryngeal bifurcation of the RLN and to demonstrate the location of the motor fibers within the branches of the RLN.
Prospective study on 99 patients over 1 year with operative data collected on the branching of a total of 137 RLNs. Operative data obtained included the type of operation, incidence of nerve bifurcation, the distance from the inferior border of the cricothyroid to the point of bifurcation, and the location of the motor fibers to the intrinsic muscles of the larynx within the branches of the RLN.
The RLN was seen intra-operatively in all patients. A total of 137 (right 69, left 68) RLNs in 99 patients undergoing thyroidectomy (total 29; hemi 51), parathyroidectomy (16) and central lymph node dissection (3) were studied. Overall, 46 RLNs (34%) bifurcated prior to entry into the larynx. These bifurcations occurred on the right in 27 (59%) and left 19 (41%). Bilateral bifurcation occurred in 12 (27%) of the 44 patients who underwent bilateral dissections. The median branching distance from the cricothyroid membrane on the right was 8.3 ± 2.5 mm, and on the left was 7.5 ± 1.8 mm. In all bifurcated RLNs, the motor fibers to the vocal cords were located exclusively in the anterior branches.
Extralaryngeal bifurcation was found in 34% of the RLNs in this case series. The motor fibers of RLN are located in the anterior branch while the posterior branch is only sensory in function. Great caution is, therefore, required after the presumed identification of the RLN to ensure there is no unidentified anterior branch. Identification of the anterior branch may lead to decreased risk of postoperative nerve injury.
识别喉返神经（RLN）的喉外分支至关重要，因为手术中误切可能导致严重的术后并发症。本研究的目的是检查 RLN 喉外分支的发生率，并展示 RLN 分支内运动纤维的位置。
对 99 例超过 1 年的患者进行前瞻性研究，收集了总共 137 条 RLN 的分支手术数据。手术数据包括手术类型、神经分支的发生率、从环状软骨下缘到分支点的距离，以及 RLN 分支内的运动纤维到喉内固有肌的位置。
所有患者均在手术中观察到 RLN。99 例接受甲状腺切除术（总 29 例；半甲状腺切除术 51 例）、甲状旁腺切除术（16 例）和中央淋巴结清扫术（3 例）的患者中，共研究了 137 条 RLN（右侧 69 条，左侧 68 条）。总体而言，46 条 RLN（34%）在进入喉前分支。这些分支在右侧发生 27 次（59%），左侧发生 19 次（41%）。在接受双侧手术的 44 例患者中，有 12 例（27%）出现双侧分支。右侧环甲膜分支距离的中位数为 8.3 ± 2.5mm，左侧为 7.5 ± 1.8mm。在所有分支的 RLN 中，声带的运动纤维仅位于前支。
在本病例系列中，34%的 RLN 存在喉外分支。RLN 的运动纤维位于前支，而后支仅具有感觉功能。因此，在假定识别 RLN 后，需要非常小心，以确保没有未识别的前支。识别前支可能会降低术后神经损伤的风险。
