Article Abstract

Continuous intraoperative neuromonitoring in minimally invasive video assisted thyroid surgery: first experience

Authors: Elias Karakas, Jakob Hinrichs, Beate Meier, Martin K. Walz, Pier Francesco Alesina


Background: Visual identification of the recurrent laryngeal nerve (RLN) is mandatory in thyroid surgery independent of the approach. Intermittent intraoperative neuromonitoring (ioNM) is broadly in open and minimally invasive thyroid surgery. However, the use of continuous intraoperative neuromonitoring (C-ioNM) has yet not been described for minimally invasive video-assisted thyroidectomy (MIVAT). The correct placement of the vagal electrode and the problem of its dislocation represent the limiting factor due to the narrow space. We describe the technique for correct electrode positioning and report on our first experiences with the C-ioNM in MIVAT.
Methods: C-ioNM was used in 9 patients eligible for MIVAT. To avoid dislocation of the electrode due to traction or interference with the electrode-wires during dissection both the wires and the electrode were pulled through an additional skin incision. MIVAT was then performed using a 5 mm 30° optical device and special instruments according to the original description from Miccoli. Video assisted hemithyroidectomy was performed in 3 patients, while 6 patients underwent total thyroidectomy.
Results: Video-assisted application of the vagal electrode and positioning of the wires via an additional access was feasible in all patients without complications. In 6 cases, the electrode-wires were pulled through an additional skin incision on the dominating side lateral to the sternocleidomastoid muscle. In two patients the wires were pulled through an additional incision in the midline below the surgical approach. In one patient the wires were diverted directly through the primary incision. A significant intermittent decrease of the electromyographic (EMG) amplitude was observed in one patient. However, postoperative RLN palsy rate was zero.
Conclusions: C-ioNM in MIVAT is feasible. An additional skin incision is helpful to avoid electrode dislocation. Traction of the thyroid lobe during thyroid lobe mobilization does not seem to affect RLN function. However, more data has to be collected to definitely estimate the significance of C-ioNM in MIVAT.