Dipti Kamani

Electrophysiologic recurrent laryngeal nerve monitoring during thyroid and parathyroid surgery: International standards guideline statement

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. Laryngoscope, 121:S1–S16, 2011

Continuous vagal IONM prevents recurrent laryngeal nerve paralysis by revealing initial EMG changes of impending neuropraxic injury: A prospective, multicenter study

Existing intraoperative neuromonitoring (IONM) formats stimulate the recurrent laryngeal nerve (RLN) intermittently, exposing it to risk for injury in between stimulations. We report electrophysiologic parameters of continuous vagal monitoring, utilizing a novel real‐time IONM format, and relate these parameters to intraoperative surgical maneuvers that delineate nascent adverse but reversible electrophysiologic parameters to prevent nerve injury. These results are correlated with postoperative vocal cord functional outcome.

Papillary thyroid carcinoma nodal surgery directed by a preoperative radiographic map utilizing CT scan and ultrasound in all primary and reoperative patients

To study the diagnostic accuracy of physical examination (PE), ultrasonography (US), contrastenhanced computed tomography (CT) and in preoperative detection of macroscopic nodal metastasis in primary/recurrent papillary thyroid carcinoma (PTC) patients to determine if the routine addition of CT would be beneficial in accurate preoperative lymph‐node surgery planning.

Superior laryngeal nerve quantitative intraoperative monitoring is possible in all thyroid surgeries

To report normative electromyography (EMG) data on the external branch of the superior laryngeal nerve (EBSLN) and to compare this to analogous data of the recurrent laryngeal nerve (RLN) and vagus nerve (VN) during intraoperative neural monitoring (IONM) using both the standard monopolar stimulator probe and a novel bipolar stimulator probe.

The nonrecurrent laryngeal nerve: Anatomic and electrophysiologic algorithm for reliable identification

The recurrent laryngeal nerve (RLN) intraoperative monitoring (IONM) provides a new functional dynamic that adds to visual identification of the RLN to optimize its intraoperative management. Intraoperative monitoring has been applied to the initial identification of the RLN. We now apply IONM to the identification of the nonrecurrent laryngeal nerve (NRLN) and provide electrophysiologic and anatomic parameters to facilitate this technique of neural identification for the NRLN, which is at increased risk of injury during thyroid surgery.

Intraoperative monitoring: Normative range associated with normal postoperative glottic function

Despite increasing use of intraoperative nerve monitoring (IONM), there is limited information on normative electrophysiologic electromyographic (EMG) parameters. The objective of this study was to define normative parameters of recurrent laryngeal nerve (RLN) intraoperative neuromonitoring during thyroid surgery associated with normal postoperative vocal cord function.

The vagus nerve, recurrent laryngeal nerve, and external branch of the superior laryngeal nerve have unique latencies allowing for intraoperative documentation of intact neural function during thyroid surgery

To define normative amplitude and latency of vagus, recurrent laryngeal nerve (RLN), and external branch of superior laryngeal nerve (EBSLN) and to apply them to postoperative neural function documentation. To our knowledge, this is the first study to report electrophysiologic characteristics of all three nerves in a consecutive patient series.

The surgical management of goiter: Part II. Surgical treatment and results†‡

Surgery for goiter embodies a unique challenge. Our objective is to provide a comprehensive analysis of cervical and substernal goiter data in two paired articles. This second article focuses on surgical management. The following null hypotheses regarding goiter excision have been tested: 1) there are no goiter‐associated risk factors for difficult intubation; 2) there are no predictive risk factors for recurrent laryngeal nerve injury (RLN) or postoperative hypocalcemia; 3) there is no difference in RLN injury with neural monitoring versus without.

Recurrent Laryngeal Nerve Monitoring during Thyroid Surgery Normative Vagal and Recurrent Laryngeal Nerve Electrophysiological Data

Objective Injury to the recurrent laryngeal nerve (RLN) remains a significant cause of morbidity during thyroid surgery. Intraoperative nerve monitoring (IONM) is being applied in many centers to facilitate nerve identification. The aim of this study was to elucidate normative human vagal and recurrent laryngeal nerve electromyograhic (EMG) parameters during standard IONM application. Study Design A prospective IONM study conducted over an 8-month period. Internal review board (IRB) approval was obtained. Settings Department of Otolaryngology, Division of Thyroid and Parathyroid Surgery, Massachusetts Eye and Ear Infirmary, Boston. Subjects and Methods All patients who were scheduled for routine thyroid, parathyroid, or neck exploration surgery were invited to participate. All patients had a preoperative and postoperative laryngeal examination to assess vocal cord function. Any patient with an abnormal preoperative laryngeal examination was excluded. Results Fifty-eight patients participated in this study. The right and left RLN latencies were similar. The left vagus latency was greater than the right vagus but was not significant. The RLN latency was significantly less than the vagus nerve. The right vagus nerve amplitude was significantly greater than the left. There was no difference between male and female amplitudes for either the RLN or vagus nerve. Conclusion This study highlights the electrophysiological/EMG differences and similarities between the RLN and vagus nerve. Normative amplitude measurements for bilateral RLN and vagus nerve stimulation are presented. There are limited data available in the literature on normal RLN and vagal EMG signals generated during thyroid surgery.

Electrophysiologic Monitoring Characteristics of the Recurrent Laryngeal Nerve Preoperatively Paralyzed or Invaded with Malignancy

Objective To elucidate electrophysiologic responses of the recurrent laryngeal nerves that were preoperatively paralyzed or invaded by malignancy and to use this information as an added functional parameter for intraoperative management of recurrent laryngeal nerves with malignant invasion. Study Design Case series with chart review. Settings Academic, tertiary care center. Subjects and Methods All consecutive neck surgeries with nerve monitoring performed by senior author (GWR) between December 1995 and January 2007 were reviewed after obtaining Institutional Review Board approval from Massachusetts Eye and Ear Infirmary Human Subjects Committee and the Partners Human Research Committee. Electrophysiologic parameters in all cases with preoperative vocal cord paralysis/paresis, and the recurrent laryngeal nerve invasion by cancer, were studied. Results Of the 1138 surgeries performed, 25 patients (2.1%) had preoperative vocal cord dysfunction. In patients with preoperative vocal cord dysfunction, recognizable recurrent laryngeal nerve electrophysiologic activity was preserved in over 50% of cases. Malignant invasion of the recurrent laryngeal nerve was found in 22 patients (1.9%). Neural invasion of the recurrent laryngeal nerve was associated with preoperative vocal cord paralysis in only 50% of these patients. In nerves invaded by malignancy, 60% maintained recognizable electrophysiologic activity, which was more commonly present and robust when vocal cord function was preserved. Conclusion Knowledge of electrophysiologic intraoperative neural monitoring provides additional functional information and, along with preoperative vocal cord function information, aids in constructing decision algorithms regarding intraoperative management of the recurrent laryngeal nerve, in prognosticating postoperative outcomes, and in patient counseling regarding postoperative expectations.