[Functional recovery after recurrent laryngeal nerve injury on different electromyography thresholds during thyroid...

Objective: To discuss the functional recovery after recurrent laryngeal nerve injury (RLNI) on different electromyography thresholds during thyroid surgery. Methods: The prospective experimentally were induced in 12 acute recurrent laryngeal traction animals (porcine) from December 2014 to December 2015, the amplitude and latency of electromyography, even time course during RLNI and recovery of 24 recurrent laryngeal nerves(RLN) were continuous intraoperative neuromonitoring(IONM), including 12 RLN releasing traction after 50% amplitude decrease (AD) and other 12 RLN after 70% AD. The IONM data and postoperative laryngoscopy result of 1 119 thyroid cancer patients, involved 237 male and 882 female, aged 45.2 years in average, who underwent thyroidectomy in Department of Thyroid Surgery, China-Japan Union Hospital Affiliated to Jilin University from July to December in 2016 were analyzed retrospectively. Results: The porcine model of traction lesion showed that the time of 50% AD was (59±4) s, latency increase (LI) was (8± 4)%, was recovered in 10 minutes; the time of 70% AD was (75±6)s, LI was (11±5)% , was recovered (43±23)% of baseline even during 20 minutes. Among the IONM of 1 632 recurrent laryngeal nerves in clinic, the mechanism of 64 RLNI is clear, including traction injury accounted for 62.5% (40/64), thermal injury was 12.5% (8/64), compression injury was 23.4% (15/64), clamp injury was 1.6% (1/64). When 50%≤AD <70% (8.8%), the rate of abnormal vocal fold movement (AVCM) was 8.8% (6/68), while AD≥70% (37.2%), the rate of AVCM was 37.2% (19/51), but LOS was 5/13. Conclusion: Releasing the injury before AD≥50% in surgery, is a more effective indicator to avoid postoperative AVCM and promote nerve function recovery.