Anatomical limits of the parapharyngeal space using a transoral endoscopic approach - Radioanatomical study in cadaver.

Purpose: The aim of this study is to obtain the anatomical limits of the parapharyngeal space by transoral surgical approach, in order to objectively determine the types of lesions according to location, where this type of approach is more indicated.

Methods: A prospective, experimental, radio-anatomical study was performed on 10 cryopreserved human heads(20 sides). A transoral approach of the parapharyngeal space was performed determining its anatomical limits by CT navigation. A statistical analysis of the registered variables was carried out.

Results: Intraoral endoscopic dissection of the parapharyngeal space was possible in all anatomical pieces (10 heads, 20 sides). The surgical technique was started by placing a laryngopharyngoscopic retractor. The scalpel incision was made from the posterior border of the hard palate, extending along the lateral border of the soft palate, following the glossopalatine arch and ending at the base of the tongue, in its posterolateral region. Under direct vision with a 0º rigid endoscope, we proceeded to the dissection by planes, identifying all the relevant vasculonervous, osseous and muscular structures. Once all the anatomical references were located, the planned measurements were taken using the surgical navigator.

Conclusions: The endoscopic intraoral approach constitutes a feasible, safe and direct access route to the parapharyngeal space. This approach would be especially indicated in lesions of the parapharyngeal space (PPS) that do not exceed the styloid and pterygoid processes cranially, do not have significant retrostylial extension and do not substantially reach the lower area of the PPS.