Beneragama Tilan, Serpell Jonathan W
Breast, Endocrine Surgery and Surgical Oncology Unit and Monash University, Frankston Hospital, Melbourne, Victoria, Australia.
ANZ J Surg. 2006 Oct;76(10):928-31. doi: 10.1111/j.1445-2197.2006.03899.x.
Extralaryngeal bifurcation and trifurcation of the recurrent laryngeal nerve (RLN) is not well described in anatomical texts. This significant anatomical variation is important because prevention of vocal cord paralysis requires preservation of all branches of the RLN. The aim of this study was to examine the prevalence of extralaryngeal bifurcation of the RLN seen during thyroid/parathyroid surgeries. All patients undergoing total thyroidectomy, hemithyroidectomy and parathyroidectomy (excluding all minimally invasive procedures) carried out by a single endocrine surgeon from November 2003 to December 2004 were included. Operative data obtained prospectively included the location of the nerve, number of branches and the distance in millimetres from the inferior border of the cricothyroid to the point of bifurcation. A total of 213 (right = 114, left = 99) RLN in 137 patients were studied. Seventy-seven (36%) nerves bifurcated or trifurcated before entry into the larynx. Bifurcations were more common on the right (43%) than on the left (28%) (P = 0.05). Trifurcations were seen in eight nerves, seven on the right and one on the left (P = 0.05). Bilaterally branched RLN were observed in 14 (18%) of 77 patients undergoing a bilateral procedure. One non-RLN was identified on the right. The median distance from the cricothyroid to the point of division was 18 mm on the right and 13 mm on the left. Extralaryngeal division of the RLN is a common anatomical variant occurring more frequently on the right. Unseen branches of the RLN are at risk of injury during surgery. Therefore, great care is required following presumed identification of the RLN to ensure that there are no other unidentified branches.
喉返神经（RLN）的喉外分支和三叉分支在解剖学文献中描述不多。这种显著的解剖变异很重要，因为预防声带麻痹需要保留RLN的所有分支。本研究的目的是检查在甲状腺/甲状旁腺手术中观察到的RLN喉外分支的发生率。纳入了2003年11月至2004年12月由一位内分泌外科医生进行的所有甲状腺全切除术、甲状腺半切除术和甲状旁腺切除术（不包括所有微创手术）的患者。前瞻性获得的手术数据包括神经的位置、分支数量以及从环甲肌下缘到分支点的毫米距离。共研究了137例患者的213条RLN（右侧 = 114条，左侧 = 99条）。77条（36%）神经在进入喉部之前发生了分支或三叉分支。右侧分支（43%）比左侧（28%）更常见（P = 0.05）。在8条神经中观察到三叉分支，右侧7条，左侧1条（P = 0.05）。在77例接受双侧手术的患者中，14例（18%）观察到双侧分支的RLN。右侧发现1条非RLN。从环甲肌到分支点的中位距离右侧为18毫米，左侧为13毫米。RLN的喉外分支是一种常见的解剖变异，在右侧更频繁发生。RLN未被发现的分支在手术中有受伤风险。因此，在假定识别出RLN后需要格外小心，以确保没有其他未识别的分支。
