An osteotomy is a standard surgical operation in which one or more bones are cut or lengthened or re-shaped. While planning for osteotomy, the surgeon sometimes uses a custom-manufactured cutting guide. The investigators are testing a relatively new approach called mixed reality navigation in planning this surgery in this study.

For the purpose of this study, the investigators will compare the accuracy of performing osteotomies with the aid of mixed reality navigation as compared to osteotomies that were performed using prefabricated cutting guides for patients in the past few years.

The use of virtual surgical planning and custom cutting guide fabrication for craniomaxillofacial osteotomies is becoming more and more common, but it remains very expensive at present, particularly for cranial procedures. As such, many practitioners utilize open-source third-party software and in-house 3D printing to aid in reducing operating costs while maintaining surgical precision and accuracy as well as the benefits of decreased intraoperative time. The use of augmented and mixed reality platforms in craniomaxillofacial surgery has demonstrated usefulness in both preoperative planning and intraoperative visualization. It has been used in the past several years during craniofacial resective procedures, orthognathic surgery, dental implantology, and surgical education.

The purpose of investigating the accuracy of preplanned craniomaxillofacial osteotomies using the aid of a mixed reality platform viewer to augment currently available navigation platforms is to demonstrate a non-inferiority of the osteotomy technique compared to the current clinical gold standard for both precision and accuracy of craniomaxillofacial osteotomies - the use of custom patient-specific cutting guides based on preoperative virtual surgical planning.

The primary objective of this prospective study is to evaluate the accuracy of craniomaxillofacial osteotomies performed with the aid of mixed reality navigation as compared to osteotomies performed using prefabricated cutting guides for similar procedures that have been planned virtually preoperatively.

The secondary objective is to determine if osteotomies performed using mixed reality navigation can be effectively completed in a minimally invasive manner.

Hypothesis: Craniomaxillofacial osteotomies performed via the mixed reality navigation method can be completed with the same degree of accuracy to a preoperative virtual surgical plan as with the use of custom printed cutting guides or within 2 mm of variance.

Sample size: n=16 patients/group to achieve a power of 0.8 and a significance level of 0.05. The investigators expect to recruit 40 patients total for the study site, including a 20% drop rate for each group

Inclusion Criteria:

• Male or female aged 16 years and older
• Has a benign or malignant mandibular or maxillary pathology who will require resection and who will undergo immediate reconstruction
• Consents to have resective and reconstructive procedures completed with the aid of mixed reality assisted navigation.

Exclusion Criteria:

1. Presence of acute infection at the time of surgery
2. Not able to speak in English or illiterate or lacking the decision-making capacity to consent for study.
3. Pregnant women because elective surgery is usually delayed until after delivery to avoid risks and complications associated with anesthetics

Study results will be published in a peer-reviewed journal upon completion and presented at appropriate conferences.