Hypoglossal nerve monitoring, a potential application of intraoperative nerve monitoring in head and neck surgery.

BACKGROUND: Intraoperative nerve monitoring (IONM) has many applications in different surgical fields. In head and neck surgery, IONM has been used to perform surgery of the parotid, thyroid and parathyroid glands, preserving the facial and recurrent nerves. However, hypoglossal nerve neuromonitoring has not been addressed with such relevance. MATERIAL AND METHODS: A retrospective review of surgeries performed on patients with special tongue and floor of mouth conditions was undertaken to examine the indications that prompted its use. Particular attention was given to the pathology, intraoperative findings and the final outcome of each patient. RESULTS: Four patients, aged between 6 years and 68 years, with complex oral tongue and floor of mouth lesions were reviewed. Three patients were male, aged 22 years and younger, and two of these patients had oral tongue cancers with previous surgery. Oral tongue and neck conditions are challenging since the functions of the hypoglossal nerve are put at risk. The use of IONM technology allowed us to preserve nerve functions, speech and swallowing. CONCLUSIONS: Although IONM of the hypoglossal nerve is not a common indication in tongue and floor of mouth lesions, under special conditions its application can be extrapolated to challenging surgical cases, like the ones described.

Facial nerve monitoring in parotid gland surgery: Design and feasibility assessment of a potential standardized technique.

Background: Even though the use of nerve monitoring during parotid gland surgery is not the gold standard to prevent damage to the nerve, it surely offers some advantages over the traditional approach. Different from thyroid surgery, where a series of steps in intraoperative nerve monitoring have been described to confirm not only the integrity but-most importantly-the function of the recurrent laryngeal nerve, in parotid gland surgery, a formal guideline to follow while dissecting the facial nerve has yet to be described. Methods: A five-year retrospective study was done reviewing the intraoperative records of patients who underwent parotid gland surgery under neural monitoring. The operative findings regarding the neuromonitoring process, particularly in regard to the amplitude of two main branches, were revised. A literature search was done to search for guidelines to follow when a facial nerve loss of signal is encountered. Results: Fifty-five patients were operated on using the Nim 3 Nerve Monitoring System (Medtronic); 31 were female patients, and 47 patients had benign lesions. Minimum changes were observed in the amplitude records after a comparison was made between the first and the last stimulation. There were only three articles discussing the term loss of signal during parotid gland surgery. Conclusion: Today, no sufficient attention has been given to the facial nerve monitoring process during parotidectomy. This study proposes a formal guideline to follow during this procedure as well as an instruction to consider when a loss of signal is observed to develop a uniform technique of facial nerve stimulation.

A randomized trial of hemithyroidectomy versus Dunhill for the surgical management of asymmetrical multinodular goiter.

OBJECTIVE: To assess the immediate and long-term clinical results of 2 different surgical procedures for the treatment of asymmetrical multinodular goiter (AMG). BACKGROUND: Half of the patients presenting with a single benign thyroid nodule have contralateral subclinical disease. There is a controversy whether these patients should be treated with hemithyroidectomy (HMT) or with a more extensive procedure. METHODS: Adult patients with a benign unilateral dominant nodule and contralateral nodule(s) with a diameter of less than 10 mm detected on neck ultrasonography were randomized to HMT or Dunhill (DUN). Rates of complications, remnant growth, incidental carcinoma, and reoperation were assessed. RESULTS: A total of 118 patients (F/M:110/8, mean age 43 years) were included and randomized: 65 to HMT and 53 to DUN. After randomization, 28 patients were excluded leaving 47 HMT and 43 DUN long-term (55 ± 35 months) evaluable patients. Mean nodule size was 38 and 6 mm for the dominant and contralateral nodules, respectively. No differences were found in operative time, accidental parathyroidectomy, parathyroid autotransplantation, or wound complications. Transient hypocalcemia was more common in DUN (30% vs 8%; P < 0.001). No permanent complications were observed. At the last follow-up visit, thyroid-stimulating hormone was similar in both groups. Remnant growth (20 vs 0%; P < 0.001), appearance of new nodules (55 vs 14%; P < 0.001), and overall reoperation rate (9.2 vs 1.8%, P = 0.2) were more common in HMT, mostly because of undiagnosed cancer requiring completion thyroidectomy. Thirty percent of HMTs developed hypothyroidism and required long-term T4 supplementation. CONCLUSIONS: DUN appears superior to HMT for the treatment of AMG in terms of early reoperation for missed carcinomas and disease progression. Both procedures have a similarly uneventful postoperative course.

Phrenic nerve stimulation during neck dissection for advanced thyroid cancer involving level IV: is it worth doing it?

During thyroidectomy and neck dissection surgery for advanced or recurrent metastatic thyroid cancer under intraoperative monitoring, we used the available technology to assess the feasibility of such an intervention to monitor those patients with phrenic nerves at risk. A retrospective review of patients operated on from January 2009 to December 2015 by a single surgeon (CSD) was conducted. Patients who had neck and mediastinal dissection, with or without total thyroidectomy, due to advanced or recurrent metastatic disease to the neck were selected. The procedures were done under intraoperative nerve monitoring using nerve monitoring systems (NIM 2.0 or 3.0; Medtronic, Jacksonville, FL, USA). A total of 19 patients were included in the study, with a mean age of 57.6 years ± 16.3 and a male/female ratio of 10:9. Overall, all patients had an intact phrenic nerve at the conclusion of the surgery. One patient had an aggressive tumor that precluded sacrifice of the left recurrent laryngeal nerve and ipsilateral thoracic duct. The procedure was complicated by a temporary impairment of the diaphragm contraction with intraoperative nerve monitoring as well as a chyle fistula. This was due to the manipulation of the tissue surrounding the phrenic nerve. Intraoperative nerve monitoring of the phrenic nerve offers the surgeon a "potential" method of ensuring phrenic nerve integrity in cases of advanced thyroid cancers with gross level IV metastatic disease. Further prospective studies are needed to assess the risks of this intervention and evaluate the method of recording diaphragm contraction movement.