Endoscopic Submandibular Retropharyngeal Approach to the Craniocervical Junction and Clivus: an Anatomic Study

Abstract

Surgery of the craniocervical junction (CCJ) and clivus is technically demanding. For many years, we have used the submandibular retropharyngeal approach for surgery of the upper cervical spine, especially hangman fracture. We hypothesized that submandibular gland resection could offer a significant cranial enlargement of the operative field, up to the clivus. Our aim in this work was to assess the feasibility of an endoscope-assisted retropharyngeal approach to the CCJ and clivus. Eight anatomic specimens were used, including 4 silicon-injected specimens. We performed a submandibular retropharyngeal approach with gland resection, and then we exposed the CCJ and clivus. We drilled the C2 vertebral body, odontoid process, C1 anterior arch, and the clivus. We noted 8 anatomic landmarks that were easily identified on each anatomic specimen. These measurements were designed to quantify the exposure of the clivus and CCJ after bone resection. A submandibular approach was feasible in all specimens. The main dimensions of the area of dural exposure after bone drilling were as follows: mean width between C1 lateral masses, 19 mm (range, 17-20 mm); at the tip of the clival window, 18 mm (range, 16-20 mm); distance between the C3 vertebra and the tip of the window within the clivus, 57 mm (range, 55-60 mm). An endoscopic submandibular retropharyngeal approach provides a simple and straightforward access to the CCJ. It also conveniently exposes the clivus. This technique could be added to the techniques used for this difficult surgery.