[Prospective analysis of the risk factors and clinical indications of dissection of lymph node posterior to right recurrent laryngeal nerve in 283 cases of papillary thyroid carcinoma].

Objective: To investigate the risk factors for metastasis and clinical indications for dissection of lymph node posterior to right recurrent laryngeal nerve (LN-prRLN) in papillary thyroid carcinoma (PTC).
Methods: A prospective analysis including 283 consecutive patients with PTC who underwent total thyroidectomy with routine central lymph node dissection (CLND) in our hospital from Jan. 2010 to Jan. 2012 was performed. The right paratracheal lymph nodes in the central compartment lymph nodes (CCLN) were divided into the anterior (level VIa) and posterior (level VIb) compartments by recurrent laryngeal nerve (RLN), and were removed respectively. The complications and recurrences were recorded with a follow-up of 3 months to 3 years.
Results: CCLN metastases were present in 47.7% (135/283) of the patients, and level VIb metastases were present in 27.2% (77/283) of the patients. The incidence of level VIb metastasis was 20.5% (58/283) in level VIa-positive patients, while 6.7% (19/283) in level VIa-negative patients. Complications of level VIb dissection were found in 4.9% (14/283) of all patients. 2.1% (6/283) of all patients were diagnosed with regional recurrence during the 3-year follow-up. Univariate analysis revealed that level VIb metastasis was significantly associated with tumor size, number, extrathyroidal invasion, clinical nodal stage, level VIa and lateral lymph node metastases. Multivariate analysis revealed that tumor larger than 1 cm, multifocality, extrathyroidal invasion, level VIa and lateral lymph node metastases were independent risk factors for level VIb metastasis.
Conclusions: Lymph node posterior to right recurrent laryngeal nerve can be the only site of metastasis from PTC without other cervical compartment involvements. Therefore, routine intraoperative detection of these nodes may be necessary for patients with right PTC, and dissection should be considered when a right-side PTC tumor is larger than 1 cm, multifocality, with extrathyroidal invasion or cervical nodal metastases.