Endoscopic Transoral Approach to the Upper Parapharyngeal Space: A Cadaveric and Clinical Applicability Study

The upper parapharyngeal space (UPPS), located immediately inferior to the middle cranial base, carries significant challenges in surgical accessibility via minimally invasive surgical approaches. This study aimed to evaluate the feasibility of performing an endoscopic-assisted transoral approach to the UPPS and confirmed the efficacy through illustration of clinical cases.

Cadaveric dissection was performed on six specimens to evaluate the feasibility of an endoscopic-assisted transoral approach to the UPPS. Twenty-two patients who harbored UPPS tumors and underwent a transoral approach for tumor extirpation were included. Functional metrics and peri-operative morbidities were assessed.

The skull base and contents in the UPPS were sufficiently exposed on all 12 cadaveric sides via the transoral approach. Via the transoral corridor, lesions in the UPPS were completely removed in all 22 patients (18 patients at pre-styloid space and 4 patients at retro-styloid space). No significant difference existed for indices of the operative time, blood loss, length of stay, time to oral intake, and return to normal diet/activities between patients with pre- and retro-styloid space tumors. Vagal palsy was encountered in two patients who harbored a retro-styloid schwannoma, while one patient healed well eventually. All 22 patients healed well, no recurrence and other obvious morbidities occurred with an average follow-up of 25.45 ± 11.63 months.

The endoscopic-assisted transoral corridor served as a viable option for carefully selected UPPS tumor removal with seemingly few complications in experienced hands.