Continuous intraoperative vagus nerve stimulation for monitoring of recurrent laryngeal nerve during minimally invasive esophagectomy

Abstract

For squamous cell carcinoma of the esophagus, extended mediastinal lymphadenectomy especially around the bilateral recurrent laryngeal nerves (RLN) is associated with high risk of nerve injury.This does not only result in hoarseness of voice, increase the chance of pulmonary complications, but would also affect the quality of life of patients in the long term. Methods to improve safety of lymphadenectomy are desirable. Continuous intraoperative nerve monitoring (CIONM) based on a system using vagus nerve stimulation was tested. In thyroidectomy, this system has been shown to be useful. Our patient cohort was when the electrical signal is picked by an electrode on the endotracheal tune. It detects the amplitude of the electromyography (EMG) of the vocalis muscle as well as its latency of nerve conduction. Reduction in amplitude and increase in latency of the laryngeal EMG signifies imminent injury to the RLN. In thyroidectomy, this system has been shown to be useful (3,4). We describe the adaptation of a commercially available continuous nerve monitoring equipment-NIM 3.0 with APS (Medtronic Inc., Jacksonville, FL, USA) for use in video-assisted thoracoscopic (VATS) minimally invasive esophagectomy (MIE). A pilot study of ten patients has been published recently (5). Patient selection and workupExtended lymphadenectomy is associated with increased morbidity; many surgeons would be selective in its application only in good risk patients. After neoadjuvant chemoradiotherapy, many would also shy away from RLN dissection, especially in the context of VATS esophagectomy. Radiotherapy may result in more fibrosis with obscured tissue planes and it is hard to differentiate cancer infiltration from post radiation fibrosis. In other cases, the tissue may actually become more edematous, easing dissection (6). In the TIME (Traditional Invasive vs. MIE) trial, the primary end-point is difference in pulmonary infection rates between open and MIE. The pulmonary complication rate and the RLN palsy rate were lower in the minimally invasive group while other complications and mortality rates were not significantly different. Bilateral RLN nodal dissection however was not routinely performed (7). Our patients were unselected; the intent was to perform bilateral RLN dissection in a consecutive group of patients. All patients had VATS esophagectomy and 52.5% had had prior chemoradiotherapy. Given the patient population, a higher RLN injury rate may be expected. The incidence of right RLN injury was expectedly to be low, since the nerve is more constant in its position and the area that requires dissection is small. But for the left side, after chemoradiation nearly twice the rate of nerve palsy was found compared to those who had not although the numbers were still small to make this statistically significant. It is the author's experience that after chemoradiation to the superior mediastinum, dissection in the left paratracheal area is more difficult. To strike a balance between striving for cure and increased morbidity, i...

Review of different approaches of the left recurrent laryngeal nerve area for lymphadenectomy during minimally invasive esophagectomy

“…In the West the trocars are placed between the scapula and the spine whereas in the East surgeons accustomed to put the trocars on lateral of the scapula (5,11). Important point of discussion is the use of an electric device to stimulate the vagal nerve for monitoring the LRLN during this lymphadenectomy (23). More evidence about this technique is needed.…”

Minimally invasive esophagectomy

“…It has no impact K review Fig. 9 Laser-induced fluorescence of indocyanine green tissue angiography for evaluation of the gastric conduit (Pinpoint Camera, Stryker Inc., USA) in operative time, but significantly reduces postoperative vocal cord palsy and consequently pulmonary complications [112][113][114][115][116][117][118][119][120].…”

Lymph Node Dissection along the Recurrent Laryngeal Nerve in Video-Assisted Thoracoscopic Surgery (VATSE) for Esophageal Squamous Cell Carcinoma

“…Wong et al demonstrated that a more aggressive and thorough nodal dissection may be possible with less concern of RLN injury by the availability of intermittent nerve mapping and continuous intraoperative nerve monitoring (CIONM) [36].…”