Elsevier

Surgery

Volume 128, Issue 6, December 2000, Pages 1082-1087
Surgery

American Association of Endocrine Surgeons
The “false” nonrecurrent inferior laryngeal nerve*,**

Presented at the 21st Annual Meeting of the American Association of Endocrine Surgeons (jointly hosted with the British Association of Endocrine Surgeons), London, United Kingdom, and Lille, France, May 22-25, 2000.
https://doi.org/10.1067/msy.2000.109966Get rights and content

Abstract

Background. Communicating branches between the cervical sympathetic system and the inferior laryngeal nerve (ILN) have been described. They usually originate from the middle cervical sympathetic ganglion (MCSG). These branches (sympathetic-inferior laryngeal anastomotic branch [SILAB]), usually thin, sometimes have the same diameter as the ILN. In this study we prospectively evaluated the frequency of this condition and its implications during surgical neck exploration. Methods. From November 1998 to October 1999, 791 patients underwent surgical neck exploration, and 1253 ILNs were dissected: 656 on the right side (52.3%) and 597 on the left side (47.7%). Results. On the right side, a nonrecurrent ILN was found in 3 cases (0.46%), and a large SILAB was found in 10 cases (1.5%). The SILAB originated from the superior cervical sympathetic ganglion in 2 cases and directly from the sympathetic trunk above the MCSG in 8 cases. No anomalous branch was found on the left side. Conclusions. The SILAB may originate not only from the MCSG but also from the superior cervical sympathetic ganglion or directly from the sympathetic trunk. When the SILAB is as large as the ILN, it could be mistaken for a nonrecurrent ILN. The awareness of this anatomic condition during neck dissection may help to avoid injuries of the genuine ILN running in the usual pathway. (Surgery 2000;128:1082-7.)

Section snippets

Material and methods

All neck dissections that we performed from November 1998 to October 1999 were included in this study. During this period, we performed operations in 791 patients: 677 patients (85.6%) for thyroid lesions, 99 patients (12.5%) for parathyroid lesions, and 15 patients (1.9%) for concomitant lesions. In the case of thyroid lesions, benign diseases accounted for 83.7% of the cases (579/692 patients) and malignant lesions for the remaining 16.3% (113/692 patients). Primary hyperparathyroidism

Results

The ILN was identified in all cases. An NRILN was found on the right side in 3 patients (0.46% of the right ILNs); in all these cases, the presence of an aberrant right subclavian artery (“arteria lusoria”) was observed and documented after operation by the presence of an additional esophageal “notch” on barium swallow test. No left NRILN was encountered. A large SILAB, with the same diameter as the ILN, was found on the right side in 10 cases (1.5% of the right ILNs); no case was observed on

Discussion

The ILN is involved in most claims concerning thyroid surgery complications.5 Its identification and complete exposure during neck dissection is considered the safest approach for thyroid and parathyroid surgery by most authors.6, 7, 8, 9 Thus, a detailed knowledge of its anatomy and of its anatomic variations is of utmost importance to avoid injuries during neck dissection. Besides the difference in origin and course between the 2 sides, numerous anatomic variations are well known (concerning

Conclusions

SILABs may originate not only from the MCSG and ICSG but also from the SCSG and directly from the sympathetic trunk. Their exact function is not very well known, but they may play a role in the vasomotor control of the larynx and perhaps in the vocal cord function.15, 16 A large SILAB may mimic an NRILN and evoke the possible coexistence of a recurrent ILN and an ipsilateral nonrecurrent ILN. Large SILABs are encountered more frequently than NRILNs. Thus, the awareness of this anatomic

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*

Reprint requests: Prof Jean François Henry, University Hospital La Timone, 264 Rue Saint Pierre, 13385 Marseilles Cedex 05, France.

**

Surgery 2000;128:1082-7.

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