Neuromonitoring Of Recurrent Laryngeal Nerve Research Articles

Standardization of Intraoperative Neuromonitoring of Recurrent Laryngeal Nerve in Thyroid Operation: To the Editor

The high average of equipment, dexterity, information, conscientious care and self-sacrificing humanity in operating rooms, great and small, here and abroad, are matters which some years of planned travel and laborious note-taking heartily attest; but evidence is not lacking that advance is very irregular where it might be all along the line, and erratic rather than on any studied and unified plan [1].

Randomized clinical trial of visualization versus neuromonitoring of recurrent laryngeal nerves during thyroidectomy

Randomized clinical trial of visualization versus neuromonitoring of recurrent laryngeal nerves during thyroidectomy

Standardization of Intraoperative Neuromonitoring of Recurrent Laryngeal Nerve in Thyroid Operation

The lack of standardized procedures of intraoperative neuromonitoring (IONM) during thyroid operations may lead to highly variable results, and many of these results can cause misleading information and, conversely, increase the risk of recurrent laryngeal nerve (RLN) injury. Therefore, standardization of IONM procedures is necessary. A total of 289 patients (435 nerves at risk) who underwent thyroidectomy by the same surgeon were enrolled in this study. Each patient was intubated with EMG endotracheal tube by the same anesthesiologist. Standardized IONM procedures were applied in each patient. The procedures include preoperative and postoperative video-recording of vocal cord movement, ensuring the correct position of electrodes after the neck was placed at full extension, vagal stimulation and registration of EMG signals before and after RLN dissection, and photographic documentation of the exposed RLN. Five patients encountered dysfunction of IONM, which was caused by malposition of electrodes and the problem was detected at once. One patient with non-RLN was detected at the earlier stage of operation. Eighteen nerves experienced loss of EMG signals during thyroid dissection, and the causes of nerve injuries were well elucidated with the application of our standardized IONM procedures. The standardized IONM procedures are useful and helpful not only to eliminate false IONM results, but also to elucidate the mechanism of RLN injury. After ascertaining the surgical pitfalls and improving the surgical techniques, the palsy rate was significantly reduced in this study.

Randomized clinical trial of visualization versus neuromonitoring of recurrent laryngeal nerves during thyroidectomy

The aim of this study was to test the hypothesis that identification of the recurrent laryngeal nerve (RLN) during thyroid surgery reduces injury, and that intraoperative nerve monitoring may be of additional benefit. One thousand consenting patients scheduled to have bilateral thyroid surgery were randomized to standard protection or additional nerve monitoring. The primary outcome measure was prevalence of RLN injury. Of 1000 nerves at risk in each group, transient and permanent RLN injuries were found respectively in 38 and 12 nerves without RLN monitoring (P = 0.011) and 19 and eight nerves with RLN monitoring (P = 0.368). The prevalence of transient RLN paresis was lower in patients who had RLN monitoring by 2.9 per cent in high-risk patients (P = 0.011) and 0.9 per cent in low-risk patients (P = 0.249). The negative and positive predictive values of RLN monitoring in predicting postoperative vocal cord function were 98.9 and 37.8 per cent respectively. Nerve monitoring decreased the incidence of transient but not permanent RLN paresis compared with visualization alone, particularly in high-risk patients. NCT00661024 (http://www.clinicaltrials.gov).

The role of intraoperative neuromonitoring of recurrent laryngeal nerve during thyroidectomy: A comparative study on 1000 nerves at risk

The role of intraoperative neuromonitoring of recurrent laryngeal nerve during thyroidectomy: A comparative study on 1000 nerves at risk

The role of intraoperative neuromonitoring of recurrent laryngeal nerve during thyroidectomy: A comparative study on 1000 nerves at risk

The role of intraoperative neuromonitoring of recurrent laryngeal nerve during thyroidectomy: A comparative study on 1000 nerves at risk

甲状腺手術における術中反回神経モニタリングシステムの有用性の検討

Introduction : Recurrent laryngeal nerve (RLN) palsy is one of the most serious complications in thyroid surgery. Intraoperative identification and preservation of the RLN is essential during thyroid surgery. The latest methods of intraoperative monitoring involve the use of special disposable endotracheal tubes with integrated electrodes. In Japan, no studies were available that evaluated whether the introduction of intraoperative neuromonitoring reduced the rate of RLN palsy. We reported our experience in using this monitoring system.Methods : Between October 2006 and June 2007, thyroid tumor surgery with intraoperative identification with and without additional intraoperative RLN neuromonitoring was performed on 53 patients. These cases were examined for postoperative nerve palsy, intraoperative blood loss and operation time.Result : The rates of RLN palsy based on nerves with or without intraoperative neuromonitoring at risk were 7.7% and 3.7% respectively. All nerve palsies were transient. These rates were not significantly different. Intraoperative blood loss and operation time were not significantly different in both group.Conclusions : The incidence of RLN palsy was not decrease by the use of intraoperative neuromonitoring; however, this monitoring system is not injurious to patients. Intraoperative neuromonitoring is recommended for high risk surgeries such as re-operation, the presence of a huge tumor, and low-volume surgeons.

The role of intraoperative neuromonitoring of recurrent laryngeal nerve during thyroidectomy: A comparative study on 1000 nerves at risk

The role of intraoperative neuromonitoring of recurrent laryngeal nerve (RLN) during thyroidectomy has not been well established. The present study evaluates whether RLN injury can be reduced by the application of this technique during thyroidectomy in a single center. Of 1000 RLNs that were at risk of injury in 639 consecutive patients who underwent thyroidectomy, the outcome of 501 RLNs with the use of neuromonitoring was compared with that of 499 nerves that were operated by routine identification only. The incidences of RLN paralysis were compared between the 2 groups and the assigned risk subgroups. Postoperative palsy was identified in 47 RLNs (4.7%), with complete recovery in 37 of 44 RLNs (84%) without documented injury. The overall incidence of postoperative RLN paralysis was significantly higher during thyroidectomy for malignancy (P = .025) and secondary thyroidectomy (P = .017). There was no significant difference in postoperative, transient, and permanent paralysis rates between the neuromonitoring and control groups. In subgroup analysis, the postoperative RLN palsy rate was higher during reoperative thyroidectomy (19% vs 4.6%; P = .019) in the control group but not in the neuromonitoring group (7.8% vs 3.8%; P > .05). Neuromonitoring of the RLN during thyroid surgery could not be demonstrated to reduce RLN injury significantly, compared with the adoption of routine RLN identification. However, its application can be considered for selected high-risk thyroidectomies.

Intraoperative Monitoring of the Recurrent Laryngeal Nerve Using Acoustic, Free-Run, and Evoked Electromyography

The purpose of this study was to explore advantages and disadvantages of electrodes used for monitoring of the recurrent laryngeal nerve (RLN) and to determine the postoperative outcome in 135 patients. A pilot study examined 11 patients to compare the clinical performance of two commercially available recording electrodes and three stimulation electrodes for RLN neuromonitoring. After determining the most reliable and consistent stimulating/recording electrode combination, 124 patients were then monitored. In a total of 135 patients there was no permanent iatrogenic nerve damage to the RLN, although 2 patients developed transient vocal hoarseness that resolved shortly postoperatively. An initial "searching" current for evoked electromyography (EMG) was delivered at 0.7 mA and then decreased to a value of 0.35 mA, which reliably elicited RLN stimulation with a minimal incidence of false-positive results. The combination of auditory feedback from the mechanically elicited EMG and a control channel involving EMG monitoring of an additional peripheral muscle improved the detection of artifact and improved the clinical efficacy of intraoperative electromyography. A video camera showed the surgical manipulation on the EMG screen, allowing the neurophysiologist to correlate dissection with RLN status and location. Auditory responses from the nerve helped to determine the type of distress the RLN was encountering.

Functional Laryngeal Results after Thyroidectomy and Extensive Recurrent Laryngeal Nerve Dissection without Neuromonitoring

BACKGROUND: Permanent recurrent laryngeal nerve palsy (RLNP) is a major complication after thyroid surgery. Therefore methods are mandatory which reduce this complication. One strategy is the identification and dissection of the recurrent laryngeal nerve (RLN) in all patients as an inflexible rule. It is an ongoing discussion whether RLN neuromonitoring is helpful. METHODS: We prospectively investigated 624 surgical patients with 1076 nerves at risk (NAR) after hemithyroidectomy or total thyroidectomy because of a benign thyroid pathology (BT). In all patients, extensive nerve dissection was performed. Electrophysiological neuromonitoring was not used. All patients were investigated both pre- and postoperatively for regular laryngeal function, using indirect laryngoscopy and videostroboscopy. RESULTS: 2.4 % temporary and 0.3 % permanent RLNPs were documented respectively. CONCLUSIONS: Reviewing the literature, the total rates of (temporary and permanent) RLNPs are identical or lower in studies performing RLN dissection compared to those where no RLN dissection had been performed. Performing RLN dissection reduced the rate of permanent RLNPs. However, our results do not imply that neuromonitoring decreases the rate of permanent RLNP, since studies that included neuromonitoring did not reveal better data. Our observations also suggest that besides indirect laryngoscopy, videostroboscopy should be performed in all patients with no evidently normal bilateral laryngeal function and no normal voice quality. Failing this, the rate of false positive or negative identification of RLNP is likely to increase.

Intraoperative neuromonitoring of surgery for benign goiter.

Recurrent laryngeal nerve (RLN) palsy is one of the most serious complications in thyroid surgery. No prospective studies are available that evaluate if the additional use of intraoperative neuromonitoring reduces the rate of RLN palsy. Between January 1 and December 31, 1998, surgery for histologically benign goiter with intraoperative identification with and without additional intraoperative RLN neuromonitoring was performed on 4,382 patients in 45 hospitals. Data were collected prospectively by questionnaire. The rate of transient and permanent RLN palsy based on nerves at risk were 1.4% and 0.4% with intraoperative neuromonitoring. These rates were significantly lower (P <0.05) compared with intraoperative visual RLN identification without intraoperative neuromonitoring which resulted in rates of 2.1% and 0.8%, respectively. A multivariate logistic regression analysis confirmed that the use of intraoperative neuromonitoring decreases the rate of postoperative transient (P <0.008) and permanent (P <0.004) RLN palsies as an independent factor by 0.58 and 0.30, respectively. Intraoperative neuromonitoring of the RLN in thyroid surgery is recommended because of significantly lower rates of transient and permanent RLN palsy rates in comparison with conventional RLN identification.