The Pterygoid Anchorage Spatial Adequacy Concept: A CT-Based Morphometric Framework for Pterygoid Implant Planning

Background/Objectives: Pterygoid implant placement remains technically demanding due to the complex three-dimensional anatomy of the pterygomaxillary region and its close relationship with critical neurovascular structures. The aim of this study was to introduce the Pterygoid Anchorage Spatial Adequacy (PASA) concept, a computed tomography (CT)-based morphometric framework for evaluating anatomical conditions relevant to pterygoid implant placement. Methods: A total of 157 CT scans were included, providing 314 pterygo-maxillo-palatal regions for analysis. Measurements included the distance between the pterygomaxillary fissure and greater palatine canal (PF–GPC), the maxillary tuberosity and greater palatine canal (MT–GPC), pterygoid process height (PPH), and anterior corridor width (PWW-1). Results: PF–GPC ≤ 4 mm was found in 69 regions (22.0%) and was associated with greater PPH and lower MT–GPC values. Age showed negative associations with MT–GPC and PWW-1, while the presence of posterior maxillary molars was associated with wider anterior corridor dimensions and larger angular parameter values. The PF–GPC distance demonstrated substantial interindividual variability, indicating that neurovascular clearance cannot be assumed to be constant. Conclusions: The PASA concept integrates neurovascular clearance, pterygoid morphology, maxillary dimensions, and dentition-related changes into a structured anatomical assessment and may contribute to more individualized preoperative anatomical assessment of pterygoid implant placement.