Are We Ready for an Optimal Neuromuscular Block Management for Neural Monitoring during Thyroid Surgery?

This article refers to:

Precision Neuromuscular Block Management for Neural Monitoring During Thyroid Surgery

In that interesting paper, the authors have showed the benefit of using low-dose sugammadex for intraoperative neural monitoring [1]. The clinical correlation from the experimental laboratory with the porcine model to the human practice is always a challenge and although that situation, the paper aims to show the feasibility of their protocols.

The idea of a balanced NMB by using lowdose sugammadex (0.5 mg/kg) to obtain partially reversal of NMB during IONM in thyroid surgery is excellent and should be implemented in the daily practice if cost can be afforded. Benefits from this strategy result in a better intubation condition, faster neuromuscular recovery and higher EMG signals compared to conventional anesthesia protocol. We need however to accept some of the limitations mentioned by the authors including the problem with dosage in obese patients, patients with higher comorbidities.

I would always consider two major steps during thyroid surgery when IONM is used. First, it is important to focus in the optimal conditions for tracheal intubation in order to have an optimal signal during all the procedure. Second, it is also difficult to ensure a timely neuromuscular function restoration for high-quality EMG signal. However, the development of novel protocols using partial NMB recovery with rocuronium at anesthesia induction and sugammadex [2].

The clinical application shows with low-dose sugammadex (0.5 mg/kg) provided timely and high-quality laryngeal EMG signal after average of 18.5 min from sugammadex injection). The presence of the EMG signal after intubation can be an issue for many surgeons. When operative time is short. Many surgeons might consider that in their practice they obtain V1 stimulation on the first side most commonly at 10–15 min from skin incision and the entire duration of surgery is 50–60 min on average. I believe that we need to have “adaptative” protocols according to each patient and surgical team and previous experience. In fact, sugammadex injection can be adjusted by the surgeon’s preference according to the different surgical experience, disease difficulty and expected surgical time. Previous protocols have been published but we need to be more adaptative and eventually give a “tailored” protocol according to clinical situation, patients characteristics and surgical team performance [2,3].

Another major point discussed is regarding the controversy between routine and selective reversal of NMB with sugammadex in monitored thyroidectomy. However, newer and more cost-effective protocols are needed in order to avoid nerve injury to recurrent laryngeal nerve (RLN) and/or external branches of superior laryngeal nerve (EBSLN) during thyroid and parathyroid surgery. We need to accept that the high cost of sugammadex remains a major hinder to its popularity. Furthermore, the different health systems and economical status of patients will give rise to diverse clinical decision-makings according to each situation.

A better approach to identify anatomical variation in RLN and EBSLN deserves further investigation. The impact of the use of blocking agent to optimize neural monitoring does not impact on mapping of the abnormal situations in RLN or EBSLN. The authors result showed that the precise NMB management ensured timely neuromuscular function restoration for high-quality EMG signal. Novel technologies will be needed in order to preoperatively or intraoperatively generate a neural mapping of the abnormal situations in RLN or EBSLN. Combination of NMB and novel technologies might guaranty the best practice in our daily basis. Novel surgical areas are now introducing neuromonitoring for the radical dissections such as esophagectomy [4].

I would like to emphasize that the benefit and efficiency of precise NMB management on facilitating neural mapping of the abnormal situations in RLN or EBSLN deserve further investigation and novel technologies should be giving better tools to surgeons [5]. Imaging? Robotics? Something still not invented?

Author contributions

RV did all the commentary.

Disclosure statement

The authors report no conflict of interest. There are no sources of support to be reported (from any of the following organizations: National Institutes of Health (NIH); Wellcome Trust; Howard Hughes Medical Institute (HHMI); and others), including no grants for doing the present work.