Neurovascular structures and invasive risks of infratemporal fossa

Approaches to infratemporal fossa are difficult due to the anatomy and the nature of the inner structures. Although endoscopic surgery and new techniques have been applied with the developing technology in recent years, it has been seen that the risks of complications cannot be avoided unless the anatomy of the region and the knowledge of possible variation are fully mastered. In this thesis, it is aimed to present the relationship between the neurovascular structures in infratemporal fossa based on the measurements and to be a guide for different branches interested with the region. The infratemporal fossa was investigated in a total of 40 sides of 20 male cadavers bilaterally, which were embalmed with a solution that contains 10% formalin in the Anatomy Department of Medical Faculty of Ege University. The dissections were performed under the guidance of trans-zygomatic and trans-mandibular techniques which are the common surgical approaches to the infratemporal fossa. In the end of the dissections maxillary and middle meningeal arteries, mandibular, inferior alveolar and lingual nerves were exposed for objectives. A metric scale was placed closely to the structures to be measured and photographs were taken at right angles. Images were transferred to a computer and the length, width, and interrelationships of the assessed structures were measured using the Image J 1.49 v software program. Two constant point were chosen for creating a straight line between them to make distance measurements. They were the midpoint of tragus (Tr) and the midpoint of the nasolabial sulcus which is the part of the lateral side of ala nasi (An). Thus the straight line between that two constant point was named as 'TrAn'. The average thickness of mandibular and pterygopalatine parts of maxillary artery, middle meningeal artery, inferior alveolar and lingual nerves are: 4.43 mm, 3.11 mm, 2.63 mm, 3.22 mm and 2.95 mm, respectively. One of the measurements for locating the oval foramen (FO) is the perpendicular distance to the TrAn line and is measured 4.29 mm on average. In addition FO-Tr distance is 49.96 mm on average. The mean FS-TrAn and Tr-FS distances for determining the position of the spinous foramen (FS) are 5.06 mm and 42.39 mm, respectively. The distance between the FO and FS (FO-FS) was found to be 7.40 mm on average. The average distances of MM-TrAn and Tr-MM for detection the branching point of middle meningeal artery from maxillary artery (MM) are respectively 14.41 mm and 38.41 mm. The average distances of Tr-Bif and Bif-TrAn to determine the branching points of inferior alveolar and lingual nerves from mandibular nerve (Bif) are 48.08 mm and 15.04 mm respectively. The sagittal distance between inferior alveolar and lingual nerves (NL-Nai) at the level of mandibular foramen is 3.32 mm on average. The absence of an anatomical study on infratemporal fossa, based on measurements and deals with such detailed and large numbers was detected with a literature review. Although studies about the same area exist, they have been carried out with less number of parameters and structures. This thesis has been planned as a pilot study for open surgical and percutaneous interventions of infratemporal fossa. Keywords: Infratemporal fossa; neurovascular structures; photogrammetric measurement.