Projected Augmented Reality in Surgery: History, Validation, and Future Applications.

Background/Objectives: Projected augmented reality (PAR) enables real-time projection of digital surgical information directly onto the operative field. This offers a hands-free, headset-free platform that is universally visible to all members of the surgical team. Compared to head-mounted display systems, which are limited by restricted fields of view, ergonomic challenges, and user exclusivity, PAR provides a more intuitive and collaborative surgical interface. When paired with artificial intelligence (AI), PAR has the potential to automate aspects of surgical planning and deliver high-precision guidance in both high-resource and global health settings. Our team is working on the development and validation of a PAR platform to dynamically project surgical and anatomic markings directly onto the patients intraoperatively. Methods: We developed a PAR system using a structured light scanner and depth camera to generate digital 3D surface reconstructions of a patient's anatomy. Surgical markings were then made digitally, and a projector was used to precisely project these points directly onto the patient's skin. We also developed a trained machine learning model that detects cleft lip landmarks and automatically designs surgical markings, with the plan to integrate this into our PAR system. Results: The PAR system accurately projected surgeon and AI-generated surgical markings onto anatomical models with sub-millimeter precision. Projections remained aligned during movement and were clearly visible to the entire surgical team without requiring wearable hardware. Conclusions: PAR integrated with AI provides accurate, real-time, and shared intraoperative guidance. This platform improves surgical precision and has broad potential for remote mentorship and global surgical training.