IONM and minimally invasive videoassisted thyroidectomy.

BACKGROUND: We know that benefits of MIVAT are related to a better cosmetic result and lower post-operative pain in comparison to CT. The incidence of nerve cold palsy is related to a correct identification of the recurrent laringeal nerve (RLN) as standard procedure in thyroid surgery. From September 2014 we have introduced the use of intraoperative neural monitoring(I-IONM) in all thyroidectomies in the Unit of General Surgery of University Hospital of Parma, including in MIVAT.

PATIENTS AND METHODS: We have considered all patients treated from September 2014 to September 2017 for thyroid diseases using MIVAT and IONM. Intermittent neuromonitoring with NIM-3.0 equipment (Medtronic, Jacksonville, FL, USA) was used during all operations. We have recorded all data about age, sex, diagnosis, surgical time, i-IONM signal, postoperative pain, postoperative hypocalcemia after 24 hours, haematoma and vocal cord palsy. The mean hospital stay was collected from surgical procedure to hospital discharge. We have considered vocal dysfunctions that persist six months after surgery as permanent.

RESULTS: From September 2014 to September 2017 we treated consecutively with both MIVAT and i-IONM 100 patients. Considering the extent of surgery, 26 pts underwent to hemithyroidectomy and 74 pts to total thyroidectomy. The mean surgical time was 61.8 minutes. In 7 cases the patients were affected by preoperative clinical dysphonia. Using I-IONM during thyroidectomy, we recorded in 5 cases (5%) a loss of signal; in two cases (2%) we experienced a temporary postoperative vocal cord palsy.

DISCUSSION: In our experience the use of IONM has improved the safety during thyroidectomy because precision that can be achieved by endoscopic procedures is further improved by complementary use of IONM. The costs associated to a potential reduction of medical litigation have not been investigated.