Retropharyngeal space and lymph nodes: an anatomical guide for surgical dissection

Identification of the alar fascia is the key part of surgical dissection of the retropharyngeal lymph nodes (RPLNs). In cases where mandibulotomy is not performed for the removal of the primary tumor and/or the posterior pharyngeal wall is not incised, the medial or lateral approaches described in this paper can be performed. Surgical dissection of the RPLNs may improve prognosis and locoregional control in oropharyngeal, hypopharyngeal and cervical esophageal carcinomas. There have been no previous anatomical studies concerning landmarks and approaches for the surgical dissection of the RPLNs. This study was designed to illustrate the fascial anatomy of the retropharyngeal region (RPR), provide anatomical guidelines for RPLN dissection and describe and compare approaches for surgical removal of the RPLNs. Twelve fixed cadavers were used. Slices were obtained from the necks of the first three cadavers and the RPRs of the slices were dissected under an operating microscope. The other nine cadavers were dissected in a surgical position to expose the RPLNs and the fasciae of the RPR. In the coronal plane, the alar fascia divides the space between the buccopharyngeal and prevertebral fasciae into two compartments and constitutes the posterior border of the retropharyngeal space, which contains the RPLNs. The alar fascia, an important landmark for reaching the RPLNs, can be identified by the cervical sympathetic trunk, superior sympathetic ganglion and superior laryngeal nerve. Two approaches can be performed to remove the RPLNs, namely medial or lateral to the internal and external carotid arteries, internal jugular vein and vagus nerve.