Objective: To investigate the clinical value of dissection of the lymph nodes posterior to the right recurrent laryngeal nerve (VIb level) during surgery for papillary thyroid carcinoma (PTC).
Methods: A total of 238 patients with PTC were enrolled as study subjects. The patients were clinically staged as cN1 in 35 cases and cN0 in 203 cases. All patients underwent thyroidectomy and central lymph node dissection (CLND). The cervical lymph node metastases of the patients and the risk factors for VIb lymph node metastasis were analyzed, and the postoperative prognosis of the patients were also observed.
Results: Among the 238 PTC patients, VIa lymph node metastasis occurred in 108 cases, VIb lymph node metastasis occurred in 67 cases, and lateral cervical lymph node metastasis occurred in 24 cases. The incidence of cervical lymph node metastases in cN1 patients was significantly higher than that in cN1 patients (94.29% vs. 46.31%, P<0.05). Results of univariate and multivariate factors showed that the maximum tumor diameter, tumor infiltration, lymph node staging, number of tumors and VIa lymph node metastasis were influential factors for VIb lymph node metastasis (all P<0.05). No injury of recurrent laryngeal nerve occurred after operation. The 3-year recurrence rate of the patients was 3.4% and the median time to recurrence was 26.3 months.
Conclusion: The maximum tumor diameter, tumor infiltration, lymph node staging, number of tumors and VIa lymph node metastasis are risk factors for VIb lymph node metastasis. In CLND, the VIb subregion should be removed as completely as possible, especially for those with the above risk factors.