8-A837A-2017-Books-00129-029-060_Katz_Sec1_Ch02-ROUND-1

C H A P T E R 2 | Oncologic Components of Lymphadenectomy

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FIGURE 2-6  Right retropharyngeal lymph node metastasis (arrow) visible on computed tomogra- phy scan enhanced with intravenous contrast.

visualization of the nerve as dissection progresses either distally or proximally along the nerve. In some instances individual lymph nodes situated posterior to the RLN can be removed separately if en bloc removal with the lymph nodes anterior to the nerve would stretch or place undue tension on the RLN. 97 Common locations of missed metastatic central compartment lymph nodes include nodes posterior to the RLN, those posterior to the common carotid artery, and those extending below the level of the sternal notch in the paraesophageal and paratracheal spaces and into the superior portion of level VII. Preservation of parathyroid gland function is important during CCND. The su- perior parathyroid glands typically derive arterial supply from branches of the infe- rior thyroid artery, and avoidance of high ligation of the inferior thyroid artery can help with preservation of the vascular pedicle. In some circumstances, a branch of the superior thyroid artery supplies the superior parathyroid glands, and confirma- tion of viability after thyroidectomy is warranted. The inferior parathyroid glands are typically more closely associated with the lymph nodes removed during CCND and may therefore be difficult or impossible to preserve in situ on their vascular pedicles (Fig. 2-7). The inferior parathyroid glands also are often in close association to or within the thyrothymic tract, which runs through the anterior aspect of the inferior level VI lymph nodes. The thyrothymic tract and cervical portion of the thymus do not necessarily need to be excised during a CCND, and preservation may aid in preserving the viability of the inferior parathyroid glands that reside in the cervical thymus. 98 De- vascularization or inability to preserve the parathyroid glands in situ should prompt reimplantation of parathyroid tissue into a viable muscle within the operative field (typically the sternocleidomastoid muscle [SCM]). Confirmation of parathyroid tissue