Author(s)
Kangsadarn Tanjararak, MD
Smita Upadhyay, MD
Thanakorn Thiensri, MD
Sawayot Rianmanee, MD
Jun Muto, MD
Daniel M Prevedello, MD
Bradley A Otto, MD
Ricardo L Carrau, MD
Affiliation(s)
Wexner Medical Center at The Ohio State University, Ramathibodi Hospital at Mahidol University, Wexner Medical Center at The Ohio State University
Abstract:
Introduction: Multiple surgical approaches to the parapharyngeal space, offering varying degrees of exposure and functional outcomes, have been previously described. Endoscopic and endoscopic assisted approaches have been applied to enhance visualization and to minimize surgical morbidities. However, the difficulty to obtain vascular control through the limited space afforded by an endoscopic route is a strong consideration when choosing a surgical approach. Therefore, surgical exposure and feasibility of vascular control should be balanced when making a decision for the best surgical route to a parapharyngeal lesion. This study aims to compare surgical exposure and vascular control of the parapharyngeal segment of the internal carotid artery (ppICA) via open and endoscopic approaches.
Study design: Anatomic study
Methods: Ten cadaveric specimens, injected with intravascular colored latex, were dissected bilaterally exposing the ppICA via endoscopic endonasal, traditional transoral, endoscopic transoral, transcervical submandibular, transcervical transparotid and transcervical transmandibular approaches respectively. Length of the exposed vessel and potential vascular control (time taken for passing the encircling suture) were assessed.
Results: The endoscopic transoral and the transcervical transmandibular approaches can expose a significant length of ppICA from the skull base to the greater cornu of the hyoid bone (mean lengths are 6.89 cm and 7.09 cm respectively). The length of ppICA exposed by endoscopic endonasal technique is limited inferiorly by the hard palate (mean length 2.715 cm) whereas, the direct exposure offered by the transcervical submandibular and the transcervical transparotid approaches only include the caudal part of the ppICA (mean leangths are 3.69 cm and 4.595 cm respectively), as they are restricted superiorly by the mandible, the facial nerve and the styloid process. Vascular control can be achieved via endoscopic endonasal, endoscopic transoral and open transcervical techniques with differing time taken 121.6, 64.8 and 5.2 seconds respectively.
Conclusion: The surgical exposure of the ppICA between the endoscopic transoral and the transcervical transmandibular approaches are comparable. The endoscopic-assistance can enhance the visualization offering a more precise dissection. In addition it can avoid the problems associated with the external scar, the mandibular osteotomy and the facial nerve manipulation. The vascular control can be achieved via both endoscopic and open transcervical approaches, however, the latter requires less time to complete. This study shows the potential of each approach however, it is not designed to accurately reflect clinical scenarios as the cadaveric model cannot mimick neither the distorted anatomy nor the bleeding associated with the rich vascular plexus encountered when managing lesions in this area.