Mixed Reality (MR) technology has emerged as a promising tool for enhancing surgical procedures and training in the operating room (OR). The applicability of MR in the OR has potential benefits and challenges. In this study, we conducted a systematic review to comprehensively evaluate the use of MR in the OR, specifically focusing on training, remote support, and surgical planning. Additionally, we analysed available tools, assessing their usability and integration into existing workflows. The analysis highlights MR solutions that improve surgical precision, visualization, decision-making, and educational experiences. The conclusions derived from the systematic review are presented, emphasizing the applicability of MR in OR and its potential contributions to training and surgical planning