[Real-time intraoperative monitoring of recurrent laryngeal nerve in thyroid surgery under general anesthesia].

Objective: To evaluate the clinical significance and application value of the real-time intraoperative monitoring (RTIM) technique in preventing recurrent laryngeal nerve (RLN) from injury during operation.

Methods: The RTIM of RLNs by nerve integrity monitor were used in 40 cases who underwent thyroid surgery under general anesthesia from Nov. 2002 to May 2005. The endotracheal intubation with laryngeal electrode sited on the tube nerve integrity monitor were adopted for general anesthesia. The RLNs in 7 cases who underwent thyroid gland lobectomy were exposed and explored and not exposed in other operations.

Results: The function of RLNs in 39 cases remained well after-operation. Only 1 patient's left RLN was damaged during operation. The spontaneous non-in-phase CMAP (compound muscle action potential) of larynx muscle in both vocal cords were recorded in all 40 cases who underwent thyroid surgery under general anesthesia. The evoked in-phase CMAP of larynx muscle could be recorded while stimulating the exposed and explored RLNs by monopolar electrode. The minimal stimulus current intensity threshold ranged from 0.08 mA to 0.35 mA (average: 0.25 mA). The range of suitable stimulating current intensity was from 0. 2 mA to 1.0 mA.

Conclusions: This technology had been proved to be more sensitive, voracious and stable. It can provide fore part precaution so that remarkably reduce the damage rate of RLN in surgery and avoid the dispensable medical dissection. It is not necessary to anatomies RLN in surgery in advance.