Accessing the Parapharyngeal Space: An Anatomical Study Comparing the Endoscopic Endonasal and the Subtemporal Preauricular Approaches

Background: A subtemporal preauricular approach to the infratemporal fossa and parapharyngeal portion of the skull base has been the traditional path to tumors of this region. However, the high morbidity associated with this procedure has lead to the pursuit of less invasive techniques. Endoscopic endonasal access utilizing a minimally invasive transmaxillary/transpterygoid approach could potentially obviate the drawbacks associated with open surgery.

Methods: A subtemporal preauricular approach and an endoscopic endonasal transmaxillary/transpterygoid approach were completed. Access was gained to the superior portion of the parapharyngeal space by making a pterional craniotomy and removing the temporal bone lateral and posterior to the foramen ovale extending to the mandibular fossa. The same area was accessed endonasally by removal of the medial and posterior wall of the maxillary sinus. The medial and lateral pterygoid plates were removed with reflection of the medial pterygoid and the tensor veli palatini muscles exposing the relevant anatomy of the parapharyngeal space.

Results: The endoscopic endonasal approach provided sufficient access to the superior portion of the parapharyngeal space. The anatomy of this region was easily identified. The open approach also provided adequate access; however it required a larger surgical window causing greater iatrogenic injury to the bone, muscles, and neurovasculature. However, the subtemporal approach did provide improved access to the petrous portion of the internal carotid artery. The endonasal approach provided improved access to the anterior and medial portions of the superior parapharyngeal space.

Conclusion: Endoscopic endonasal access using a transmaxillary/transpterygoid approach provided a sufficient surgical window for tumor extirpation. Use of this approach obviated the morbidity associated with an open procedure. Further understanding of the endoscopic anatomy of this region can lead to improvements in morbidity associated with tumor resection in this dense neurovascular region.