The Combined Endoscopic Transcervical - Transoral Robotic Approach for Resection of Parapharyngeal Space Tumors

Background: The parapharyngeal space (PPS) presents challenges during surgical exposure. Parapharyngeal space tumors (PPST) are routinely resected by transcervical approach using blunt finger dissection, while the critical part of the operation is performed in a blind fashion, applying pressure on the tumor, increasing the risk of tumor spillage and of neurovascular injury. Large PPST or those located high at the lateral skull base, often require mandibulotomy, or infratemporal fossa approach, baring considerable morbidity.

Objectives: To describe a novel minimally invasive approach to the PPST.

Methods: The combined transcervical endoscopic, transoral robotic approach utilizes endoscopic equipment introduced transcervically for circumferential separation of the tumor from the neurovascular structures of the skull base. After the tumor is separated from the carotid artery and cranial nerves, it is removed en-bloc, via transoral robotic surgery (TORS).

Results: We describe our experience with 2 cases. A woman who presented with intractable headaches, and MRI demonstrating an egg-shaped 5x4 cm sized mass partly solid partly cystic, at the left PPS. Combined endoscopic transcervical-Transoral robotic approach was performed. Total surgical time was 2 hours and 40 minute, with 20 minutes of robotic utilization. No intra-, peri-, or postoperative complications were encountered. Pathology results showed pleomorphic adenoma. Postoperative MRI showed complete tumor resection. The second case was of a man who underwent CT and MRI because of an asymmetric palate. The imaging studies demonstrated a 6 cm mass at the right PPS. FNA was suspicious for pleomorphic adenoma. He underwent the surgery in the combined approach. Final pathology result showed carcinoma ex pleomorphic adenoma, non invasive, intracapsular. The technique provides improved visualization throughout the surgery, and safe vascular control with minimum tumor stress. This method prevents the need of blunt/blind finger dissections and allows complete tumor removal while minimizing tumor spillage, nerve injury and blood loss.

Conclusions: This approach could be utilized for the removal of large benign PPST, or small PPST located high. A small neck incision and endoscopic technique allow better exposure in comparison to traditional approaches, while maintaining excellent cosmetic and functional results.