Intraoperative Displacement of a Pterygoid Implant into the Pterygopalatine Fossa and Its Surgical Retrieval: A Case Report

Background/Objectives: Pterygoid implants are increasingly used to provide distal support in full-arch maxillary rehabilitation, improving biomechanical stability and reducing posterior cantilevers. Despite high reported survival rates, their placement is technically demanding because of the complex anatomy of the pterygomaxillary region and the proximity of critical neurovascular structures. Implant displacement into adjacent deep anatomical spaces is a rare but potentially serious complication. The aim of this report is to describe the management of sequential intraoperative complications involving pterygoid implants—initial migration into the maxillary sinus followed by displacement into the pterygopalatine fossa—and to analyse the technical factors that contributed to them. Case Description: A 68-year-old woman underwent full-arch maxillary rehabilitation with eight implants, including bilateral pterygoid implants. Both pterygoid implants showed progressively decreasing primary stability and migrated into the maxillary sinus. During a salvage attempt, a newly inserted pterygoid implant deviated and was displaced beyond the pyramidal process into the pterygopalatine fossa together with the insertion driver. Cone-beam computed tomography (CBCT) localized the implant—lying medial to the lateral pterygoid plate, anterior to the pterygoid process—and guided a targeted retrieval based on careful blunt dissection, performed in an outpatient setting without general anesthesia or endoscopic assistance. A correctly positioned pterygoid implant was then placed. The anterior implants (insertion torque > 60 N·cm) were immediately loaded; at four months the right pterygoid implant was uncovered, and the left implant retained in the sinus was retrieved and replaced using a trans-sinus technique with elevation of the Schneiderian membrane. Conclusions: This case highlights the importance of accurate, consistent anatomical localization, complete osteotomy preparation, appropriate implant selection, and controlled, torque-monitored insertion during pterygoid implant placement. It also demonstrates that rare displacement of an implant into a deep anatomical space can be safely managed in an outpatient dental setting by experienced clinicians using a structured, image-guided approach.