Ultrasound-Guided Transoral Videolaryngoscopic Surgery for Retropharyngeal Lymph Node Metastasis of Papillary Thyroid Cancer

BACKGROUND: Endoscopic-assisted transoral surgery, including transoral robotic surgery for metastatic retropharyngeal lymph node (RPN) from well-differentiated thyroid cancer, has been reported to reduce the complications resulting from transcervical and transmandibular approaches. However, the narrow working space and difficulty identifying RPN are problematic. To solve these issues, several studies have used intraoperative ultrasound in endoscopic-assisted transoral surgery. However, the type of ultrasonography suitable for this purpose remains unclear. CASE PRESENTATION: A 60-year-old female with thyroid papillary carcinoma (T4aN1bM0) initially underwent total thyroidectomy and paratracheal and selective neck dissections (D2a), with resectional management of recurrent laryngeal nerve, trachea, and esophagus. Three years later, she was diagnosed with left retropharyngeal and upper mediastinal lymph node metastases of papillary thyroid cancer. Transoral videolaryngoscopic surgery was performed with a combination of ultrasonography with a flexible laparoscopic transducer manipulated with forceps for identifying RPN intraoperatively. Due to the transducer's small size and thin, flexible cable, the transducer interrupted the procedure in spite of the narrowness of oral cavity. RPN was resected completely without adverse events. CONCLUSION: We performed intraoperative ultrasound-guided endoscopic transoral surgery for metastatic RPN from papillary thyroid cancer and achieved complete resection as well as preservation of swallowing function.