Recurrent nerve monitoring for thyroid and parathyroid surgery contraindicates the pharmacologically active presence of muscle relaxant agents at the time of dissection. A recent formalized expert guideline (RFE 2018) from the French Society of Anesthesia and Resuscitation, SFAR recommends administering a curare to facilitate tracheal intubation and limit laryngeal trauma . This study aims to determine if the level of neuromuscular recovery is consistent with monitoring the recurrent nerve after the use of rocuronium for intubation.

Primary endpoint: Achievement of quality intraoperative laryngeal recurrent nerve monitoring.

The monitoring of the recurrent nerves, innervating the vocal cords, in thyroid and parathyroid surgery has developed in recent years because of its interest as a parameter to reduce the risk of recurrent paralysis.

Monitoring of the recurrent nerves requires contraction of the laryngeal muscle and therefore contraindicates the pharmacologically active presence of muscle relaxants at the time of dissection. Thus, intubation was performed either without curare or with a depolarizing curare (Succinylcholine) whose short duration of action allowed optimal intubation conditions without intraoperative residual effect.

This practice is being questioned due to :

(i) a recent formalized expert referential (RFE) of the French Society of Anesthesia and Resuscitation, SFAR, which recommends administering a curare to facilitate intubation of the trachea and limit laryngeal trauma (grade 1 +) and (ii) a restriction of the indications of succinylcholine by the French National Agency for the Safety of Medicines and Health Products, ANSM, as an adjuvant of general anaesthesia (induction in rapid sequence and electroconvulsive therapy).

In summary, thyroid surgery requires curarisation for intubation and sufficient intraoperative decurarisation to allow monitoring of the recurrent nerves. We hypothesize that the time between intubation and the actual start of recurrent monitoring is consistent with the time to recovery of laryngeal adductor neuromuscular block after injection of rocuronium at a dosage of 0.5 mg/kg.

Inclusion Criteria:

• Adult subjects requiring general anesthesia for cephalic surgery (thyroid and parathyroid) with an NIM-type intubation tube.
• Subject informed of the study and not having opposed it

Exclusion Criteria:

• Allergy to any of the products used
• Morbidly obese subjects (BMI> 35)
• Pregnancy
• Predictive criteria for difficult intubation in pre-anesthetic consultation
• Subjects under tutorship or curatorship
• Subjects not affiliated to social security

Major, non-morbidly obese patients (BMI<35) requiring general anesthesia with intubation with a Nerve Integrity Monitor (NIM) tube for thyroid and parathyroid surgery.