Radiological assessment of dissected cervical lymph nodes in Level III affected by the area of supraomohyoid neck dissection

Objectives To compare the number of dissected cervical lymph nodes in the anatomical Level III with that in supraomohyoid neck dissection (SOHND) Level III affected by the anatomical relationship between the omohyoid muscle and cricoid cartilage using contrast-enhanced CT (CE-CT) images to assess the validity of the current SOHND. Methods CE-CT images of the patients who suffered from malignant tumors in the oral and maxillofacial regions were reviewed. The number of cervical lymph nodes both in the anatomical Level III (area between the center of the inferior border of the hyoid bone (HB) and the inferior border of the cricoid cartilage (CC)) and SOHND Level III (area between HB and the intersection of the omohyoid muscle and internal jugular vein (OM-IJ)), were recorded respectively. Results The rate of patients whose number of lymph nodes in Level III was affected by the positional relationship between the OM-IJ and CC was almost equal in males and females. As for the patients with OM-IJ below the CC, the number of lymph nodes in SOHND Level III increased from that of anatomical Level III. Females showed significantly higher values than males (p < 0.05). Meanwhile, for patients with OM-IJ at or above the CC, the number of lymph nodes in SOHND Level III decreased from that of anatomical Level III. Conclusions The number of dissected cervical lymph nodes differed between the SOHND dissection area and Levels I, II, and III. In most cases, SOHND dissects more cervical lymph nodes, especially in female patients.