Related Experiment Video
Updated: Jul 6, 2026
Intra-Operative Neural Monitoring of Thyroid Surgery in a Porcine Model
Published on: February 11, 2019
Ultrastructural and Automated Vocal Fold Tracking Study in Recurrent Laryngeal Nerve Injury Models
Yanli Ma1, Lu Xing2, Xiaoyong Ren3
1Department of Otorhinolaryngology Head and Neck Surgery, the Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, PR China; Department of Voice Medicine, Zhongshan Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen 361004, PR China.
Objective:
This study aims to assess nerve regeneration characteristics and their impact on vocal fold (VF) movement after unilateral recurrent laryngeal nerve (URLN) injuries to inform clinical treatment strategies.
Methods:
Four types of URLN injury models in rabbits were created: clamp, electrocautery, transection, and ligation. Nerve damage and regeneration were evaluated using electron microscopy at 2, 4, 8, and 12 weeks postinjury. VF movement range and speed were assessed using tracking software.
Results:
The N-ratio (the ratio of myelinated axon area to total nerve trunk area) and myelinated axon density (MAD, the number of axons per unit area): clamp group were the highest at all times compared to the other groups. Postinjury, the electrocautery group was higher than the transection and ligation groups, except at 2 weeks. In the clamp and electrocautery groups, N-ratio and MAD increased between 4 and 8 weeks postinjury. At 4 weeks, 100% of the clamp group and 66.7% of the electrocautery group showed partial recovery of injured VF movement. Compared to the normal VF, the affected VF's mean motion range (MMR) was 22% less (P < 0.05), and mean motion speed (MMS) was 58% slower (P < 0.05). At 8 weeks, MMR was 7% less (P < 0.05), and MMS was 41% slower (P < 0.05). At 12 weeks, MAD started to decrease. However, the N-ratio continued to increase. MMR was 2% lower (P > 0.05), and MMS was 24% slower (P < 0.05).
Conclusion:
The severity of RLN injuries was as follows: ligation > transection > electrocautery > clamp injury. Recovery of VF motion range preceded recovery of motion speed. Asynchronous motion of bilateral VFs was a characteristic feature of RLN injury repair.
