Intraoperative nerve monitoring during thyroid surgery

Effects of Intraoperative Nerve Monitoring Techniques on Voice and Swallowing Disorders after Uncomplicated Thyroidectomy: Preliminary Report of a Bi-Institutional Prospective Study

Background: Voice and swallowing problems are frequently associated with thyroidectomy. Intermittent nerve monitoring (i-IONM) seems to provide a positive effect in reducing its prevalence. The aim of this study was to test the hypothesis that continuous intraoperative nerve monitoring (c-IONM) may reduce the prevalence of these disorders even further than i-IONM. Methods: This 3-arm prospective bi-institutional study compared 179 consecutive patients that underwent thyroidectomy: 56 without IONM, 55 with i-IONM and 67 with c-IONM. Neck dissections and laryngeal nerve palsies were excluded. Two questionnaires (VHI-10 for voice disorders and EAT-10 for swallowing disorders; both validated for Italian language use) were administered before and 1 month after surgery. Statistical significance was analyzed by the chi-squared test. Results: After thyroidectomy, no statistically significant differences were found in the three groups concerning EAT-10. although these symptoms seemed to be influenced by gastro-esophageal reflux. VHI-10 worsened in the “no-IONM” group compared with both i-IONM (p < 0.09, not quite statistically significant) and c-IONM (p < 0.04). Conclusion: Both i- and c-IONM improve voice quality independently of laryngeal nerve integrity. Reduced dissection and particularly restrained manipulation could explain these results, being particularly favorable for c-IONM.

Study on Changes in Immune Function After Microwave Ablation of Papillary Thyroid Microcarcinoma

Background

In recent years, papillary thyroid microcarcinoma (PTMC) has been a main cause of the high incidence of thyroid carcinoma. No existing study has reported whether microwave ablation (MWA) affects patients' immunity. Therefore, this study explored the effects of MWA treatment on the immune functions of patients with PTMC.

Methods

This study included 50 patients diagnosed with PTMC who received MWA treatment under ultrasound guidance at the ultrasound department of our hospital from January 2019 to October 2020. Changes in immune function after MWA treatment in PTMC patients were detected by T lymphocyte subsets and cytokines secreted by T helper cells.

Results

At 1 day and 2 weeks after MWA treatment, the proportions of CD3⁺, CD4⁺ and CD4⁺/CD8⁺ T lymphocyte subsets and the levels of the cytokines interleukin (IL)-2 and interferon (IFN)-γ in the peripheral blood of the patients were significantly higher than those before MWA treatment (P<0.05). The levels of CD8⁺ T lymphocytes, tumour necrosis factor (TNF)-α, IL-4, IL-6, IL-10 and IL-17A were not significantly different from those before MWA treatment (P>0.05). One month after MWA treatment, the proportions of CD3⁺, CD4⁺, CD8⁺ and CD4⁺/CD8⁺ T lymphocytes and the levels of the cytokines IL-2, IL-4, IL-6, IL-10, IFN-γ, TNF-α and IL-17A were not significantly different from those before MWA treatment (P>0.05).

Conclusion

The immune functions of patients with PTMC are temporarily enhanced after MWA treatment, which has important clinical significance for patients' anti-PTMC ability.

A new anesthesia scheme for parathyroidectomy under neuromonitoring: a retrospective cohort study

Background

Parathyroidectomy under nerve monitoring has been carried out for nearly ten years in the China-Japan Union Hospital of Jilin University. We retrospectively evaluated patients' prognosis with secondary hyperparathyroidism (SH) under neuro- and non-neuro-monitored parathyroidectomy anesthesia. The purpose of this study is to summarize and introduce a new anesthesia scheme for parathyroidectomy under nerve monitoring.

Methods

From January 2000 to December 2019, 200 patients with SH in the China-Japan Union Hospital of Jilin University were retrospectively analyzed. Among them, 100 patients underwent parathyroidectomy under neurological monitoring (Group A), and 100 patients underwent parathyroidectomy without neurological monitoring (Group B). The dosage of muscle relaxant, parathyroid hormone (PTH), serum calcium, phosphorus, urea, creatinine, and alkaline phosphatase (ALP) was recorded before surgery (T0), after surgery (T1), at discharge (T2), during skin incision (Ta), at four parathyroidectomies (Tb), and 10 min after total removal. The levels of PTH were measured at four-time points (Tc) and 30 minutes (Td) after complete resection.

Results

After screening and propensity score match (PSM), the data of 92 patients were analyzed. Group A's muscle relaxant dose was significantly less than Group B; the length of hospital stay in Group A was significantly lower than in Group B (P<0.05). The serum calcium levels, phosphorus, urea, and creatinine at T2 in Group A were lower than those in Group B (P<0.05).

Conclusions

Parathyroid nerve monitoring technology combined with preoperative complete anesthesia scheme, anesthesia induction with one time ED95 (95% effective drug dose) cis-atracurium, end breath gas, and sevoflurane maintenance anesthesia under BIS monitoring can improve the prognosis of patients, shorten the length of hospital stay, and is effective and safe.

Low-Dose of Rocuronium During Thyroid Surgery: Effects on Intraoperative Nerve-Monitoring and Intubation

BACKGROUND

Intraoperative Neurophysiological Monitoring (IONM) reduces the incidence of Recurrent Laryngeal Nerve (RLN) injuries during thyroid surgery. To preserve nerve function, long acting neuromuscular blocking agents (NMBA) should be avoided. However, NMBA are necessary for laryngoscopy and endotracheal intubation. We designed this double-blinded, randomized, placebo-controlled trial to assess if a low-dose of rocuronium given at intubation would affect the IONM data recorded before the thyroid dissection.

METHODS

Hundred patients undergoing elective thyroid surgery were randomized to receive either 0.3 mg kg^-1 of low dose rocuronium (intervention) or no-NMBA (control). Intubation was performed with video-laryngoscopy. IONM was placed on RLN and nerve stimulation was performed before and after thyroid dissection. The presence of a valid amplitude prior to dissection was defined when the IONM signal was >100 μV. Occurrence of difficult laryngoscopy was reported together with intubation details including time, difficulty and failure. The lowest peripheral saturation (SpO₂) and the number of desaturation episodes during the intubation were also registered.

RESULTS

No patients showed impaired IONM signal before dissection in both groups. Cormack-Lehane grade was higher in the intervention group (1^1;2) compared to control one (1^1;1; P = 0.046). No-NMBA patients had increased number of difficult laryngoscopies (21% versus 6%, P = 0.041) and intubations (34% versus 8%; P = 0.003) as well as a longer time to intubation (78 [55; 175] versus 55 [31; 110] sec; P = 0.006). Lower values of peripheral SpO₂ during intubation attempt were registered in the no NMBA group (99 [97; 100] versus 99 [99; 100] %; P = 0.020). However, the number of intubation failure was similar between groups (p=0.495).

CONCLUSIONS

Low-dose of rocuronium does not compromise pre-dissection IONM signal and improves intubation condition when compared to a relaxant free strategy.

Predictors and consequences of recurrent laryngeal nerve injury during open thyroidectomy: An American College of Surgeons National Surgical Quality Improvement Project database analysis

BACKGROUND

Recurrent laryngeal nerve (RLN) injury is a serious complication of thyroidectomy. The purpose of this study is to determine the predictors and consequences of RLN injury during thyroidectomy.

METHODS

A retrospective analysis was conducted using the ACS-NSQIP 2016-2017 main and thyroidectomy targeted procedure databases. Data was analyzed by multivariate logistic regression resulting in risk-adjusted odds ratios of RLN injury and morbidity/mortality.

RESULTS

Age ≥65, black race, neoplastic indication, total or subtotal thyroidectomy, concurrent neck surgery, operation time > median, hypoalbuminemia, and anemia were associated with RLN injury. Use of intraoperative nerve monitoring was associated with decreased RLN injuries. RLN injury is a risk factor for overall morbidity, hypocalcemia, hematoma, pulmonary morbidity, readmission, reoperation, and length of stay > median.

CONCLUSION

Several predictors of RLN injury during thyroidectomy are identified, while use of intraoperative nerve monitoring was associated with a decreased risk of RLN injury. RLN injury is associated increased postoperative complications.

Efficacy of Transcartilaginous Electrodes for Intraoperative Neural Monitoring During Thyroid Surgery

Objectives.

This study was conducted evaluate the efficacy of electromyography (EMG) using transcartilaginous (TC) electrodes through the thyroid cartilage and perichondrium.

Methods.

We prospectively collected EMG data from intraoperative neuromonitoring (IONM) of 54 nerves at risk in 38 patients during thyroidectomy. We followed standardized IONM procedures in all operations. EMG signals from both endotracheal tube (ET) electrodes and TC needle electrodes were recorded simultaneously. We compared the characteristics of the EMG signals and the efficacy of both methods.

Results.

Significantly higher mean EMG amplitudes were recorded by TC electrodes than by ET electrodes in all four-step procedures (V1-R1-R2-V2, P<0.001). Loss of signal (LOS) occurred in five patients in ET electrodes, but in only two patients in TC electrodes. Postoperative laryngoscopy revealed recurrent laryngeal nerve palsy in the two patients who showed LOS from both the ET and TC electrodes, and vocal cord movement was intact in the other three patients. Therefore, the positive predictive values of LOS in ET and TC electrodes were 40% and 100%, respectively.

Conclusion.

EMG recording using TC needle electrodes is feasible and effective, making it a good alternative technique for IONM.

Minimally invasive esophagectomy and radical lymph node dissection without recurrent laryngeal nerve paralysis

Background

We introduce a novel operative technique to dissect lymph nodes adjacent to the recurrent laryngeal nerve, referred to as the “native tissue preservation” technique. Using this technique, there was no damage to the recurrent laryngeal nerve, which is maintained in its anatomical position.

Methods

From September 2016 to December 2018, minimally invasive esophagectomy was performed in the left lateral decubitus position in 87 patients with esophageal cancer. The native tissue preservation technique for lymphadenectomy around the recurrent laryngeal nerve was used, and all patients were evaluated for recurrent laryngeal nerve paralysis.

Results

Minimally invasive esophagectomy was completed in all patients without conversion to thoracotomy. Although an extended lymphadenectomy was performed in all patients, there were no grade II or higher complications (Clavien–Dindo classification) and no incidence of recurrent laryngeal nerve paralysis.

Conclusion

The native tissue preservation technique may reduce the incidence of recurrent laryngeal nerve paralysis after minimally invasive esophagectomy with radical lymph node dissection.

Electronic supplementary material

The online version of this article (10.1007/s00464-020-07372-3) contains supplementary material, which is available to authorized users.

Effect of nerve monitoring on complications of thyroid surgery

OBJECTIVE:

The most frequent and critical complications of thyroid surgery are recurrent laryngeal nerve palsy and hypocalcemia. In first years of the 21st century, intraoperative neuromonitoring (IONM) was introduced as a new technique to avoid the recurrent laryngeal nerve (RLN) injury. However, the role and the benefits of IONM are still controversial. In this study, we aimed to compare the postoperative complication rates during thyroid surgery with IONM usage (Group 1) and conventional direct visual technique without IONM usage (Group 2).

METHODS:

We conducted retrospective review of all patients undergoing thyroid surgery in Lütfiye Nuri Burat State Hospital General Surgery Department between 2014 and 2016 years. Patients have been classified in to two groups: Group 1 and 2.

RESULTS:

Overall, 191 patients were included in the study; Group 1 comprised 79 patients and Group 2 comprised 112 patients. Unilateral RLN paralysis was observed in 7 patients in Group 1 (8.9%) and 15 patients in Group 2 (13.4%) without any significant difference between the groups (p=0.368). Hypocalcemia was encountered in 5 patients (6.3%) in Group 1 and 18 patients (16.1%) in Group 2; this difference was statistically significant (p=0.045). Other complications (such as hematoma and suture reaction) were not significantly different. Operation time was found to be significantly shorter in Group 1 (Mean time, 93.08 min) than in Group 2 (116.54 min) (p=0.03).

CONCLUSION:

Proven effect of IONM on RLN paralysis is still controversial. However, easy identification of RLN, which gives more confidence to surgeon, and shorter operation time may be factors to lower hypocalcemia rates.