AbstractIntroduction: The parapharyngeal space is an anatomically defined region, part of the seven compartments of the deep head and neck. The space is frequently entered when resecting neoplasms of the tongue base, tonsil, and parapharyngeal space. The transoral surgical approaches to gain access to these regions rose in popularity recently due to advancements in transoral robotic surgery. We aim to describe the topographical anatomy of the parapharyngeal space to facilitate safe operating in this area.
Methods: Fifteen formalin-fixed cadaveric head and neck specimens were dissected on both sides with a surgical microscope. Two specimens were sectioned sagitally and thirteen were sectioned coronally. Photographs were taken at each step of the dissection while gainig acess to and defining the neurovasculature of the parapharyngeal space. Mean measurements were made from select anatomical landmarks to neurovasculature of the parapharyngeal space.
Results: The parapharyngeal part of the lingual artery was a mean distance of 21mm from the base of tongue midline. The lingual artery was 3.5mm superior to the greater cornu of hyoid bone. The hypoglossal nerve was a mean distance of 26.3mm from the epiglottic vallecula. The apex of the tonsillar fossa was on average 16.1mm far from the internal carotid artery. The midpoint of the stylopharyngeus muscle was 2.1mm posterolaterally to the internal carotid artery. The glossopharyngeal nerve was a mean distance of 5mm from the styloid process. The styloglossus muscle midpoint was 14.6mm superior to the facial artery. The distal attachment of the stylopharyngeus and styloglossus muscle is a highly vascular area. The facial artery was 9.5mm from the oropharyngeal mucosa. The lingual nerve was 3mm from the lateral surface of the pharyngeal constrictor muscle at its parapharyngeal portion before entering the mouth.
Conclusion: Topographic observations and mean proximity distances obtained in this study may have the potential to add to the inside-to-outside anatomy of the parapharyngeal space for surgeons accessing this space via the transoral route and transoral robotic surgery. The area parallel to the base of tongue where the stylopharyngeus attach to the pharynx, and styloglossus muscle’s distal attachment site at the base of tongue represents a highly vascular area supplied by branches directly from the external carotid artery, superior thyroid artery, lingual artery, and the facial artery.
|Date of Award||15 Jun 2019|
|Supervisor||Peter Jones (Supervisor), Athanasios Raikos (Supervisor), Allan Stirling (Supervisor) & Samuel Dowthwaite (Supervisor)|