Endoscopic Study for the Pterygopalatine Fossa Anatomy

OBJECTIVE: The purposes of this study were to locate the constant anatomic landmarks, which are very important and helpful for endoscopic surgery and not well described for the pterygopalatine fossa (PPF) surgery via the middle nasal meatus-sphenopalatine foramen approach to establish a safe surgical mode. METHODS: Eight cases of adult skull specimens were selected for the simulated surgery. The Messerklinger surgical approach was used under the endoscope. The uncinate process was removed successively, and the anterior ethmoid sinus and posterior ethmoid sinus were opened. The opening of the maxillary sinus was identified and was expanded forward and backward. The ethmoidal crest was found and was used as an anatomic landmark to find the sphenopalatine foramen. The sphenopalatine artery was protected and was used as a guide to enter the PPF region. The sphenopalatine artery was followed conversely to anatomize the blood vessels and nerves in the PPF. RESULTS: It was found that our surgical procedure provides a clear view of the constant anatomic landmark including ethmoidal crest and sphenopalatine foramen. By retrograde dissection, following the sphenopalatine artery, which runs out of the sphenopalatine foramen behind the ethmoidal crest, the internal maxillary artery (IMA) and the branches of the IMA in the PPF were exposed. Posterior to the sphenopalatine artery, the typical Y-shaped structure with the pterygopalatine ganglion as the center was visible when the IMA and its branches were moved downward and outward. The Y structure, which is consisted of the pterygopalatine ganglion, branches of the internal maxillary nerve, vidian nerve, and descending palatine nerve, served as the other anatomic landmark. By following the Y structure, it was easy to locate the pterygoid canal, foramen rotundum, and the infraorbital nerve, and the integrity of the nerve structure could be protected. CONCLUSION: Endoscopic PPF surgery via the middle nasal meatus-sphenopalatine foramen approach is safe, and the ethmoidal crest, sphenopalatine foramen, and Y structure with the pterygopalatine ganglion in the center are important anatomic landmarks that can be referred to during the surgery.