ORIGINAL ARTICLE ENDONASAL TRANSPTERYGOID APPROACH TO THE INFRATEMPORAL FOSSA: CORRELATION OF ENDOSCOPIC AND MULTIPLANAR CT ANATOMY Seid Mousa Sadr Hosseini, MD, 1 Ali Razfar, MD, 2 Ricardo L. Carrau, MD, 3 Daniel M. Prevedello, MD, 4 Juan Fernandez–Miranda, MD, 5 Adam Zanation, MD, 6 Amin B. Kassam, MD 3 1 Department of Otolaryngology–Head & Neck Surgery, Vali-E-Asr Hospital, Tehran University of Medical Sciences, Tehran, Iran 2 Department of Surgery–Division of Head and Neck Surgery, University of California Los Angeles Medical Center, Los Angeles, California 3 Neuroscience Institute, John Wayne Cancer Institute at Saint John’s Health Center, Santa Monica, California. E-mail: carraurl@gmail.com 4 Department of Neurosurgery, Ohio State University Medical Center, Columbus, Ohio 5 Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania 6 Department of Otolaryngology–Head & Neck Surgery, University of North Carolina. Chapel Hill, North Carolina Accepted 14 December 2010 Published online 16 May 2011 in Wiley Online Library (wileyonlinelibrary.com). DOI: 10.1002/hed.21725 Abstract: Background. The infratemporal fossa anatomy, from an endoscopic standpoint, is poorly understood. Our pur- pose was to design an anatomic model that illustrates the anatomy of the infratemporal fossa from the endoscopic stand- point and serves as a training model for surgeons interested in pursuing this endeavor. Methods. Red and blue silicone dyes were respectively injected into the great vessels of the neck. Digital data acquired from a high resolution CT scan was imported to a navigational system. An endoscopic endonasal dissection of the infratemporal fossa was completed under conditions that mimicked our operating suite. Results. A detailed anatomic dissection of the infratempo- ral fossa was correlated to the image guidance (navigation) system. This provided a surgical map highlighting critical neu- rovascular structures and illustrating the potential surgical corridors. Conclusion. A thorough understanding of the anatomy of infratemporal fossa from the endoscopic perspective allows the surgeon to plan an adequate corridor. V V C 2011 Wiley Peri- odicals, Inc. Head Neck 34: 313–320, 2012 Keywords: endoscopy; training model; anatomy; infratemporal fossa; pterygopalatine fossa Surgical access to the infratemporal fossa is difficult, as this area is deeply seated. Briefly, the infratempo- ral fossa is situated beneath the floor of the middle cranial fossa, posterior to the maxillary sinus, medial to the ramus of the mandible, and lateral to the naso- pharynx. The greater wing of the sphenoid bone and the subtemporal surface of the temporal bone form the roof of the infratemporal fossa. The lateral ptery- goid plate along with the eustachian tube forms its medial wall. The deep aspect of temporalis muscle inserting to the mandibular ramus and the temporo- mandibular joint bounds the infratemporal fossa in its lateral aspect (Figure 1). The infratemporal fossa houses the lateral and medial pterygoid muscles, and important neurovascu- lar structures, such as the third branch of the trigem- inal nerve (V3), the internal maxillary artery, and the carotid sheath and its contents. The lateral pterygoid muscle (LPM) occupies most of the superior infratem- poral fossa. Caudally, the infratemporal fossa is pri- marily occupied by the medial pterygoid muscle, which inserts into the angle of mandible. Posterome- dially, the infratemporal fossa contains the carotid sheath (internal carotid artery [ICA], internal jugular vein, and cranial nerves IX to XII) and styloid com- plex (ie, parapharyngeal space). 1 In addition, the in- ternal maxillary artery (IMA), pterygoid venous plexus, maxillary vein, and the mandibular and chorda tympani nerves all traverse through the infra- temporal fossa (ie, masticator space). 2,3 Medially, the infratemporal fossa communicates with the pterygo- palatine fossa via the pterygomaxillary fissure, which is continuous with the inferior orbital fissure. A variety of benign and malignant neoplasms involve the infratemporal fossa. However, most neo- plasms involving the infratemporal fossa originate from adjacent structures, such as the temporal bone, parotid gland, paranasal sinuses, nasopharynx, or temporal fossa. Juvenile angiofibroma and adenoid cystic carcinoma are the most common benign and malignant tumors involving the infratemporal fossa, Correspondence to: R. L. Carrau V V C 2011 Wiley Periodicals, Inc. Correlation of Endoscopic and Multiplanar CT Anatomy HEAD & NECK—DOI 10.1002/hed March 2012 313