Redefining the Surgical Map for the Parapharyngeal Space: Anatomic Feasibility of a Transoral Endoscopic Approach and a Novel Lymph Node Compartmentalization

Objective: The parapharyngeal space (PPS) is a frequent site of nodal metastasis from skull base malignancies, yet its surgical management is complicated by deep and complex anatomy. This study evaluates the anatomical feasibility of an endoscopic transoral medial pterygomandibular approach for parapharyngeal lymphadenectomy, aiming to define a safe and effective minimally invasive corridor. Methods: We performed a detailed anatomical dissection on five fresh-frozen cadaveric heads (10 sides). The surgical anatomy for an endoscopic transoral approach was systematically delineated. Based on our findings, we developed a novel compartmentalization framework for transoral parapharyngeal lymphadenectomy. Key anatomical landmarks, including the glossopharyngeal nerve, stylopharyngeus muscle, and styloglossus muscle, were precisely identified, and their spatial relationships were quantified to establish a reliable system for surgical navigation. The area of tissue resected was calculated using ImageJ software to quantify the extent of dissection. Results: The endoscopic transoral approach afforded a direct and minimally invasive corridor to the parapharyngeal lymphatic basin. We demonstrated that selective transection of the stylopharyngeus and styloglossus muscles significantly enhances surgical exposure of the inferior PPS. The glossopharyngeal nerve and the parapharyngeal segment of the internal carotid artery were consistently identified as the critical structures defining the limits of safe dissection. To improve surgical orientation, we propose a novel compartmentalization of the PPS lymphatics using the styloid diaphragm and the glossopharyngeal nerve as primary demarcating boundaries. Navigational landmarks were reliably established: the vaginal process of the tympanic bone and the styloid process guide identification of the superior glossopharyngeal nerve, while the stylopharyngeus and styloglossus muscles serve as robust markers for its inferior course. The facial and lingual arteries were found to be consistent landmarks for the inferior dissection border. Surgeons must remain vigilant for anatomical variations, particularly regading the course of the parapharyngeal internal carotid artery and the origin of the lingual artery. Conclusion: The endoscopic transoral medial pterygomandibular approach is an anatomically sound and feasible technique for parapharyngeal lymphadenectomy. This approach, guided by our proposed compartmentalization system and defined anatomical landmarks, has the potential to offer a less morbid alternative to traditional open surgery for managing nodal disease in this challenging region. Further clinical validation is warranted to confirm these promising anatomical findings. Fig. 1 Stepwise Lymph node Dissection of the Parapharyngeal Space (PPS) via the Endoscopic Transoral Medial Pterygomandibular Fold Approach. Fig. 2 Delineation of the Three Surgical Subregions for Transoral Endoscopic Parapharyngeal Lymphadenectomy. Fig. 3 Clinically Significant Anatomical Variations Encountered During the Transoral Endoscopic Approach. Publication History Article published online: 27 February 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany