Intraoperative neural monitoring (IONM) during thyroid and parathyroid surgery has gained widespread acceptance as an adjunct to the gold standard of visual nerve identification. Despite the increasing use of IONM, review of the literature and clinical experience confirms there is little uniformity in application of and results from nerve monitoring across different centers. We provide a review of the literature and cumulative experience of the multidisciplinary International Neural Monitoring Study Group with IONM spanning  nearly 15 years. The study group focused its initial work on formulation of standards in IONM as it relates to important areas: 1) standards of equipment setup/endotracheal tube placement and 2) standards of loss of signal evaluation/intraoperative problem-solving algorithm. The use of standardized methods and reporting will provide greater uniformity in application of IONM. In  addition, this report clarifies the limitations of IONM and helps identify areas  where additional research is necessary. This guideline is, at its forefront, quality driven; it is intended to improve the quality of neural monitoring, to translate the best available evidence into clinical practice to promote best practices. We hope this work will minimize inappropriate variations in monitoring rather than to dictate practice options.

BACKGROUND: Recurrent laryngeal nerve (RLN) palsy ranks among the leading reasons for medicolegal litigation of surgeons because of its attendant reduction in quality of life. As a risk minimization tool, intraoperative nerve monitoring (IONM) has been introduced to verify RLN function integrity intraoperatively. Nevertheless, a systematic evidence-based assessment of this novel health technology has not been performed.

METHODS: The present study was based on a systematic appraisal of the literature  using evidence-based criteria.

RESULTS: Recurrent laryngeal nerve palsy rates (RLNPR) varied widely after thyroid surgery, ranging from 0%-7.1% for transient RLN palsy to 0%-11% forpermanent RLN palsy. These rates did not differ much from those reported for visual nerve identification without the use of IONM. Six studies with more than100 nerves at risk (NAR) each evaluated RLNPR by contrasting IONM with visual nerve identification only. Recurrent laryngeal nerve palsy rates tended to be lower with IONM than without it, but this difference was not statisticallysignificant. Six additional studies compared IONM findings with their corresponding postoperative laryngoscopic results. Those studies revealed high negative predictive values (NPV; 92%-100%), but relatively low and variable positive predictive values (PPV; 10%-90%) for IONM, limiting its utility for intraoperative RLN management.

CONCLUSIONS: Apart from navigating the surgeon through challenging anatomies, IONM may lend itself as a routine adjunct to the gold standard of visual nerve identification. To further reduce the number of false negative IONM signals, the causes underlying its relatively low PPV require additional clarification.

OBJECTIVE: This study was designed to provide an update on the pathophysiological concepts and patient management in a common complication of thyroid surgery, unilateral recurrent laryngeal nerve paralysis (URLNP).

METHOD: Recent publications in physiology and head and neck surgery were reviewed. Results: Even for experienced surgeons, URLNP may occur after thyroid surgery, especially for thyroid cancer and in case of reoperation. URLNP is frequently well tolerated but may be life threatening by inducing aspiration pneumonia. Permanent URLNP may decrease quality of life by decreasing voice quality and increasing vocal effort. Spontaneous recovery of vocal function, with or without full recovery of vocal fold motion, may occur due to spontaneous axonal regrowth or other neurological phenomena. In the last decade, several surgical techniques have been developed to treat aspiration and poor voice quality due to URLNP by medialization of the paralyzed vocal fold. These techniques are simple, have a low complication rate, and are highly efficient in  eliminating aspiration and improving voice quality and quality of life.

CONCLUSIONS: The voice and swallowing handicap caused by URLNP may be efficiently treated by safe and simple techniques. The possibility to improve the quality of life should be proposed to all patients with symptomatic URLNP.