Handling the recurrent laryngeal nerve (RLN) in thyroid surgery: Intraoperative versus postoperative knowledge of RLN function

Abstract

Dear Editor,Dr. Stevens and associates [1] reported their comprehensive experience in the use of intraoperative neuromonitoring (NM). Current standards for recurrent laryngeal nerve (RLN) management during thyroid surgery consist of an extensive knowledge of RLN anatomy, routine visual identification, and exposure of the nerve, experience as well as pre-and post-operative laryngoscopy [2].Standards of care do change over time, and innovations have been applied in thyroid surgery [1,3]. We are in transition period from the era of visualization to the era of neurophysiology of the RLN [4]. With current technology, today it is feasible to monitor intraoperatively (not longer postoperatively) the RLN function with NM [3,4].De facto, which are the fundamental difference between an intraoperative versus postoperative knowledge of a RLN preserved function? Therefore, which are the difference between NM versus a postoperative videolaryngoscopy, or a composite of acoustic measurements, and clinician-perceived voice quality performed after thyroidectomy [1]?In addition to reducing the risk of RLN deficits [5], the use of neurophysiological techniques can provide information and guidance that can help the surgeon carry out safely the operation and make better decisions (surgical strategy) about next step in the operation [6,7]. Wang et al. [6] revealed that a dose of intraoperative corticosteroids did shorten the recovery time for patients suffering from temporary RLN palsy. Goretzki et al. [7] demonstrated that a failed NM stimulation after resection of the first thyroid lobe is specific enough to reconsider the surgical strategy in patients with bilateral thyroid disease to surely prevent bilateral RLN palsy. In its simplest form, NM may consist of identifying the exact anatomical location of the nerve that cannot be identified visually (anatomical nerve lesions are only exceptional reasons for postoperative vocal cord palsy) [4], or it may consist of identifying where (and how) in the RLN a block of transmission has occurred (to repair the nerve) [3,8]. Moreover, NM adds early and definite localization and confirmation of RLN during dissection, to prevent visual misidentification, to avoid excessive traction, to identify extralaryngeal branches, anatomical variation, distored RLN, non-RLN.The intraoperative assessment of RLN function with NM is important for several other reasons: (a) intraoperative prediction of postoperative function (prognosis); (b) early differentiation between RLN-related and unrelated voice changes; (c) documentation [3,8].Finally, NM in thyroid surgery aids the anesthesiologist as (a) indicates periods of light anestesia; (b) eliminates the need for visual assessment of vocal cord function at the time of extubation (c) indicates the potential for bilateral vocal cord paralysis [7,8].Thus, intraoperative knowledge of RLN function is useful and strongly advised in the modern era of surgery. However, videolaryngoscopy is essential in all cases while NM is in the development phase to improve the prog...

Risk of Recurrent laryngeal Nerve Injury In Complete Resection OF Recurrent Multi-nodular Goiter

“…In addition, most nerve injuries are not recognized intraoperatively and visualization of the nerve is insufficient to assess nerve damage. 1 Injury of RLN is generally unilateral and transient, but occasionally it can be bilateral and permanent and it may be either accidental. The permanent lesion of damaged RLN often manifests as an irreversible dysfunction of phonation and is the most common complication following surgery.…”