[Total-endoscopic Thyroid Resection in ABBA-Technique: Comments on the Integration of Intraoperative Neuromonitoring]

Background: Total endoscopic thyroid resections without any scars on the neck are a special challenge for the surgeon. Clinical results of intraoperative neuromonitoring (IONM) in the axillo-bilateral-breast-approach (ABBA) have not been described so far. Methods: 29 female patients (~ 40 years) were operated for one-sided thyroid pathology using the ABBA technique (20 subtotal resections, 9 hemithyroidectomies). Suspected malignoma, size > 35 mL, known thyroiditis and recurrencies were excluded. For stimulation a 30-cm handprobe and for signal deviation a tube adhesive electrode (ISIS; Fa. Inomed, Emmendingen, Germany) were used. Results: The average operation time was 132 minutes. Intraoperative blood loss necessitated conversion to the open procedure in 1 case. A single tube electrode dislocation occurred. In the alternative a bipolar needle electrode was inserted percutaneously through the cricothyroid ligament. One intraoperative signal loss was confirmed by the laryngoscopic finding of vocal cord paresis, which recovered within 6 months. An additional case of incomplete brachial plexus paralysis was observed with a 2-day recovery time. Conclusion: Direct neuromonitoring of the recurrent laryngeal nerve can be easily applied in the total endoscopic ABBA technique for thyroid resection. Vagal stimulation, which is obligatory in open thyroid surgery, cannot consequently be included in this endoscopic operation method. Unexpected tube electrode dislocation may cause IONM misinterpretation. A risk of double-sided vocal cord palsy is theoretically present.