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treatment. 82,83 Reoperative lymph node dissection for persistent and recurrent PTC carries a higher risk of surgical complications than does primary surgery. 84 These is- sues underscore the utmost importance of accurate and complete preoperative and intraoperative analysis to allow for a definitive resection of both local and regional disease at the time of initial surgical treatment of PTC. An ipsilateral therapeutic CCND should be performed for macroscopic metastatic lymphadenopathy; if macroscopic disease is seen in the contralateral central compart- ment, bilateral therapeutic CCND should be performed. 85–87 The role of a contra- lateral CCND, in the absence of a known contralateral cancer and no macroscopic evidence of metastatic lymphadenopathy in the contralateral central compartment, is controversial. However, intraoperative inspection of the central compartment has a poor predictive value for the presence of metastatic disease, and consideration could be given to proceeding with a contralateral dissection in the presence of ipsilateral macroscopic disease. 88,89 Intraoperative decision-making plays an important role in the conduct of CCND. After ipsilateral dissection, the functional status of the RLN should be considered prior to completing the contralateral CCND, if being considered. Intraoperative RLN monitoring can be helpful in this decision-making process. For example, if the RLN is nonfunctional after the ipsilateral CCND, surgeons should carefully consider the implications before proceeding with a contralateral dissection. This is especially per- tinent in the absence of clinically involved lymph nodes, considering the ramifications of bilateral RLN paralysis and the subsequent need for tracheostomy. A staged pro- cedure might also be considered; however, if a total thyroidectomy has already been performed, the contralateral central compartment will become a reoperative field, which may be associated with higher rates of RLN injury or hypoparathyroidism. The viability of the parathyroid glands should also be a consideration during bilateral CCND. Care should be taken to preserve all parathyroid glands. If multiple glands have questionable viability, a limited contralateral dissection can be considered in order to preserve viable parathyroid tissue in those patients with no evidence of con- tralateral metastatic lymphadenopathy. Technical Aspects CCND typically can be accomplished through the lower cervical collar incision used for thyroidectomy. The central compartment of the neck is defined by anatomic boundaries, and CCND should be performed in a compartment-oriented manner, with en bloc resection of the lymph nodes contained within these boundaries. 78,90,91 The central compartment is bounded cranially by the hyoid bone, caudally by the innominate artery on the right and the corresponding axial plane on the left, later- ally by the common carotid arteries, posteriorly by the deep layer of the cervical fascia, and anteriorly by the superficial layer of the cervical fascia (Fig. 2-3). The thyroid and parathyroid glands, the level VI lymph nodes, the upper portion of the level VII lymph nodes, and the cervical portion of the thymus are within the central compartment. Common locations of metastatic central compartment lymph nodes include the paratracheal and paraesophageal lymph nodes inferior and posterior to