Radiological assessment of the dissection area in supraomohyoid neck dissection

Area of Science:

• Anatomy
• Surgical Oncology
• Radiology

Background:

• Supraomohyoid neck dissection (SOHND) is a standard procedure for targeting cervical lymph node levels I, II, and III.
• The anatomical boundary between levels III and IV is defined by the inferior border of the cricoid cartilage.
• The precise relationship between the omohyoid muscle and cricoid cartilage in SOHND requires further anatomical validation.

Purpose of the Study:

• To investigate the anatomical relationship between the omohyoid muscle and cricoid cartilage using contrast-enhanced CT (CE-CT).
• To assess the validity of the current supraomohyoid neck dissection (SOHND) based on anatomical findings.
• To determine if SOHND accurately confines dissection to levels I, II, and III.

Main Methods:

• Review of contrast-enhanced CT (CE-CT) images of head and neck regions.
• Categorization of patients into "malignant tumors" and "others" groups.
• Recording vertebral levels of the omohyoid muscle-internal jugular vein intersection (OM-IJ) and cricoid cartilage (CC).

Main Results:

• The OM-IJ was located between the 7th cervical and 1st thoracic vertebrae.
• The CC was located between the 6th and 7th cervical vertebrae.
• Females exhibited a significantly lower OM-IJ compared to males, and both sexes showed OM-IJ lower than CC, suggesting SOHND may extend into level IV.

Conclusions:

• The study provides anatomical evidence that the SOHND dissection area differs from the intended levels I, II, and III.
• SOHND frequently involves level IV, especially in female patients, due to the anatomical positioning of the omohyoid muscle relative to the cricoid cartilage.
• Findings suggest a need to re-evaluate the anatomical boundaries and extent of SOHND procedures.