Background: Prophylactic central neck dissection (CND) has been proposed in the treatment of patients affected by papillary thyroid carcinoma (PTC) with clinically negative neck lymph nodes. The procedure allows pathologic staging of lymph nodes of the central compartment and treatment of the micrometastases. Nevertheless, the morbidity that its routine use adds to the total thyroidectomy must be taken into account. The aim of this study was to characterize the morbidity that CND adds to the total thyroidectomy.
Methods: This was a retrospective study of 1087 patients with PTC and clinically negative neck lymph nodes. Patients were divided into three study groups: Group A, total thyroidectomy; Group B, total thyroidectomy and ipsilateral CND; Group C, total thyroidectomy and bilateral CND. Primary endpoints of the study were evaluated by comparing the rates of transient and permanent recurrent laryngeal nerve (RLN) injury and hypoparathyroidism in the three study groups.
Results: Analysis of data showed no significant differences in the rate of transient (Group A: 3.6%, Group B: 3.9%, and Group C: 5.5%; p=0.404) and permanent (Group A: 1%, Group B: 0.5%, and Group C: 2.3%; p=0.099) RLN injury between the three study groups. Both ipsilateral CND and bilateral CND were associated with a higher rate of transient hypoparathyroidism (Group: A 27.7%, Group B: 36.1%, and Group C: 51.9%; p=0.014; odds ratio [OR]: 1.477; 95% confidence interval [CI]: 1.091-2.001; p<0.001; OR: 2.827; 95% CI: 2.065-3.870, respectively). Bilateral CND had a higher rate of permanent hypoparathyroidism (Group A: 6.3%, Group B: 7%, and Group C: 16.2%; p<0.001; OR: 2.860; 95% CI: 1.725-4.743).
Conclusions: The increased rates of transient and permanent hypoparathyroidism in our series suggest a critical review of indications for the routine use of prophylactic CND for PTC. Prophylactic CND ipsilateral to the tumor associated with total thyroidectomy may represent an effective strategy for reducing the rate of permanent hypoparathyroidism. Concomitant completion contralateral paratracheal lymph node neck dissection should be performed in presence of lymph node metastasis on intraoperative frozen-section pathology. This approach limits the use of bilateral CND to patients with intraoperative pathological findings of lymph node metastases.