A feasibility study of a new method to enhance the augmented reality navigation effect in mandibular angle split osteotomy

Advanced outcomes of mixed reality usage in orthognathic surgery: a systematic review

INTRODUCTION

Orthognathic surgery (OGS) is a highly sophisticated surgical technique that aims to repair a variety of skeletal and dental abnormalities, including misaligned jaws and teeth. It requires precise preoperative preparation and advanced surgical skills, which are typically learned through years of practical experience in operating rooms or laboratory-based surgical training facilities utilizing cadavers or models. The traditional physical hands-on method of surgical training is still used at OGS. However, this method requires a longer time of preparation. Currently, mixed reality (MR)-a combination of virtual reality and augmented reality technology-is an innovation of OGS. The present study aimed to present a comprehensive review of studies that assessed the advantages of utilizing mixed reality technology in OGS.

METHODS

A modified Population, Intervention, Comparison, Outcome strategy was performed using a combination of electronic (PubMed, Cochrane, Embase) and manual searches between 2013 and 2023 exploring mixed reality (MR) technology in OGS in the last 10 years. The inclusion criteria were limited to the patient and study model focusing on the clinical application of MR and the associated field of OGS.

RESULT

The initial search indicated 1731 studies, of which 17 studies were included for analysis. The main results indicated that the use of MR technology in OGS led to high accuracy and time reduction as primary outcomes and cost-effectiveness and skill improvement as secondary outcomes. The review firmly concluded that MR technology exhibited a positive impact on students, trainees, and oromaxillofacial surgeons. However, due to the heterogeneity of the included studies, meta-analyses could not be performed. Collectively, these findings provide strong evidence for the advantages of MR technology in orthognathic surgery.

CONCLUSION

MR technology significantly improves OGS planning efficiency by providing pre-surgical information and serving as an intraoperative navigation tool, reducing surgical time without compromising outcomes. Virtual training using MR technology exerts a positive impact on knowledge and skill improvement for OGS. This innovative technology will revolutionize the healthcare system and enhance patient care.

Augmented and Virtual Reality Applications in Facial Plastic Surgery: A Scoping Review

OBJECTIVES

Augmented reality (AR) and virtual reality (VR) are emerging technologies with wide potential applications in health care. We performed a scoping review of the current literature on the application of augmented and VR in the field of facial plastic and reconstructive surgery (FPRS).

DATA SOURCES

PubMed and Web of Science.

REVIEW METHODS

According to PRISMA guidelines, PubMed and Web of Science were used to perform a scoping review of literature regarding the utilization of AR and/or VR relevant to FPRS.

RESULTS

Fifty-eight articles spanning 1997-2023 met the criteria for review. Five overarching categories of AR and/or VR applications were identified across the articles: preoperative, intraoperative, training/education, feasibility, and technical. The following clinical areas were identified: burn, craniomaxillofacial surgery (CMF), face transplant, face lift, facial analysis, facial palsy, free flaps, head and neck surgery, injectables, locoregional flaps, mandible reconstruction, mandibuloplasty, microtia, skin cancer, oculoplastic surgery, rhinology, rhinoplasty, and trauma.

CONCLUSION

AR and VR have broad applications in FPRS. AR for surgical navigation may have the most emerging potential in CMF surgery and free flap harvest. VR is useful as distraction analgesia for patients and as an immersive training tool for surgeons. More data on these technologies' direct impact on objective clinical outcomes are still needed.

LEVEL OF EVIDENCE

N/A Laryngoscope, 134:2568-2577, 2024.

The HoloLens in medicine: A systematic review and taxonomy

The HoloLens (Microsoft Corp., Redmond, WA), a head-worn, optically see-through augmented reality (AR) display, is the main player in the recent boost in medical AR research. In this systematic review, we provide a comprehensive overview of the usage of the first-generation HoloLens within the medical domain, from its release in March 2016, until the year of 2021. We identified 217 relevant publications through a systematic search of the PubMed, Scopus, IEEE Xplore and SpringerLink databases. We propose a new taxonomy including use case, technical methodology for registration and tracking, data sources, visualization as well as validation and evaluation, and analyze the retrieved publications accordingly. We find that the bulk of research focuses on supporting physicians during interventions, where the HoloLens is promising for procedures usually performed without image guidance. However, the consensus is that accuracy and reliability are still too low to replace conventional guidance systems. Medical students are the second most common target group, where AR-enhanced medical simulators emerge as a promising technology. While concerns about human-computer interactions, usability and perception are frequently mentioned, hardly any concepts to overcome these issues have been proposed. Instead, registration and tracking lie at the core of most reviewed publications, nevertheless only few of them propose innovative concepts in this direction. Finally, we find that the validation of HoloLens applications suffers from a lack of standardized and rigorous evaluation protocols. We hope that this review can advance medical AR research by identifying gaps in the current literature, to pave the way for novel, innovative directions and translation into the medical routine.

Three-dimensional technologies in presurgical planning of bone surgeries: current evidence and future perspectives

BACKGROUND

The recent development of three-dimensional (3D) technologies introduces a novel set of opportunities to the medical field in general, and specifically to surgery. The preoperative phase has proven to be a critical factor in surgical success. Utilization of 3D technologies has the potential to improve preoperative planning and overall surgical outcomes. In this narrative review article, the authors describe existing clinical data pertaining to the current use of 3D printing, virtual reality, and augmented reality in the preoperative phase of bone surgery.

METHODS

The methodology included keyword-based literature search in PubMed and Google Scholar for original articles published between 2014 and 2022. After excluding studies performed in nonbone surgery disciplines, data from 61 studies of five different surgical disciplines were processed to be included in this narrative review.

RESULTS

Among the mentioned technologies, 3D printing is currently the most advanced in terms of clinical use, predominantly creating anatomical models and patient-specific instruments that provide high-quality operative preparation. Virtual reality allows to set a surgical plan and to further simulate the procedure via a 2D screen or head mounted display. Augmented reality is found to be useful for surgical simulation upon 3D printed anatomical models or virtual phantoms.

CONCLUSIONS

Overall, 3D technologies are gradually becoming an integral part of a surgeon's preoperative toolbox, allowing for increased surgical accuracy and reduction of operation time, mainly in complex and unique surgical cases. This may eventually lead to improved surgical outcomes, thereby optimizing the personalized surgical approach.

Systematic review of techniques used to validate the registration of augmented-reality images using a head-mounted device to navigate surgery

Augmented-reality (AR) head-mounted devices (HMD) allow the wearer to have digital images superposed on to their field of vision. They are being used to superpose annotations on to the surgical field akin to a navigation system. This review examines published validation studies on HMD-AR systems, their reported protocols, and outcomes. The aim was to establish commonalities and an acceptable registration outcome. Multiple databases were systematically searched for relevant articles between January 2015 and January 2021. Studies that examined the registration of AR content using a HMD to guide surgery were eligible for inclusion. The country of origin, year of publication, medical specialty, HMD device, software, and method of registration, were recorded. A meta-analysis of the mean registration error was conducted. A total of 4784 papers were identified, of which 23 met the inclusion criteria. They included studies using HoloLens (Microsoft) (n = 22) and nVisor ST60 (NVIS Inc) (n = 1). Sixty-six per cent of studies were in hard tissue specialties. Eleven studies reported registration errors using pattern markers (mean (SD) 2.6 (1.8) mm), and four reported registration errors using surface markers (mean (SD) 3.8 (3.7) mm). Three studies reported registration errors using manual alignment (mean (SD) 2.2 (1.3) mm). The majority of studies in this review used in-house software with a variety of registration methods and reported errors. The mean registration error calculated in this study can be considered as a minimum acceptable standard. It should be taken into consideration when procedural applications are selected.

Assessment of Robot-Assisted Mandibular Contouring Surgery in Comparison With Traditional Surgery: A Prospective, Single-Center, Randomized Controlled Trial

BACKGROUND

Few clinical studies on robot-assisted surgery (RAS) for mandibular contouring have been reported.

OBJECTIVES

The aim of this study was to follow the long-term effectiveness and safety of RAS for craniofacial bone surgery.

METHODS

This small-sample, early-phase, prospective, randomized controlled study included patients diagnosed with mandibular deformity requiring mandibular contouring surgery. Patients of both genders aged 18 to 30 years without complicated craniofacial repair defects were enrolled and randomly assigned in a 1:1 ratio by a permuted-block randomized assignments list generated by the study statistician. The primary outcomes were the positioning accuracy and accuracy of the osteotomy plane angle 1 week after surgery. Surgical auxiliary measurement index, patient satisfaction scale, surgical pain scale, perioperative period, and complications at 1 week, 1 month, and 6 months after surgery were also analyzed.

RESULTS

One patient was lost to follow-up, resulting in a total of 14 patients in the traditional surgery group and 15 in the robot-assisted group (mean [standard deviation] age, 22.65 [3.60] years). Among the primary outcomes, there was a significant difference in the positioning accuracy (2.91 mm vs 1.65 mm; P < 0.01) and angle accuracy (13.26º vs 4.85º; P < 0.01) between the 2 groups. Secondary outcomes did not significantly differ.

CONCLUSIONS

Compared to traditional surgery, robot-assisted mandibular contouring surgery showed improved precision in bone shaving, as well as higher safety.

LEVEL OF EVIDENCE: 2

The application of augmented reality in craniofacial bone fracture reduction: study protocol for a randomized controlled trial

Background

Augmented reality (AR) is a new technology that increases users’ perception of the real world. The purpose of this study is to evaluate the efficacy and safety of augmented reality navigation system in treatment with craniofacial fracture reduction.

Methods

This will be a single-center prospective randomized controlled trial. Twenty-two patients will be assigned to two groups of 11, and those with zygomaticomaxillary complex fractures will undergo preoperative three-dimensional CT modeling and have operational plans designed. The control team will use traditional optical navigation to perform the surgery, and the experimental team will use an AR navigation system. The primary outcome measures will be the accuracy of the key points of surgical area between the preoperational surgical plan and post-operation. The secondary outcome measures will be the blood loss, operation time, bone reduction time, hospital time, and complication rate. The findings obtained through this study are expected to evaluate efficacy and safety of the augmented reality navigation system in the treatment of zygomaticomaxillary complex fractures.

Discussion

This controlled trial of augmented reality navigation system in treatment with zygomaticomaxillary complex fracture reduction will clarify the efficacy and safety of this technology by measuring the accuracy of the key points of surgical area and blood loss, operation and bone reduction times, hospital stay duration, and complication rates. This is a single-center study, and the results are expected to promote the application of augmented reality in craniofacial fracture reduction to improve surgery accuracy and efficacy.

Trial registration

Chinese Clinical Trial Registry ChiCTR1900022626. Registered on April 19, 2019.

Key Ergonomics Requirements and Possible Mechanical Solutions for Augmented Reality Head-Mounted Displays in Surgery

In the context of a European project, we identified over 150 requirements for the development of an augmented reality (AR) head-mounted display (HMD) specifically tailored to support highly challenging manual surgical procedures. The requirements were established by surgeons from different specialties and by industrial players working in the surgical field who had strong commitments to the exploitation of this technology. Some of these requirements were specific to the project, while others can be seen as key requirements for the implementation of an efficient and reliable AR headset to be used to support manual activities in the peripersonal space. The aim of this work is to describe these ergonomic requirements that impact the mechanical design of the HMDs, the possible innovative solutions to these requirements, and how these solutions have been used to implement the AR headset in surgical navigation. We also report the results of a preliminary qualitative evaluation of the AR headset by three surgeons.

Application of Augmented Reality Navigation in Treatment With Fibrosis Dysplasia

OBJECTIVE

In order to reduce the possibility of accidental injury to neurovascular and important tissues, this research conduct preoperative design and intraoperative guidance for fibrous dysplasia through augmented reality technology.

METHODS

Five patients with fibrous dysplasia were selected for three-dimensional (3D) computed tomography (CT) scan and 3D model was reconstructed. Considering the navigation plan was comprehensively, the guide plate (composed of card groove, connector, and fixator) was designed and 3D printed. Three-dimensional software was used to unify the coordinates of the surgical plan and the guide plate, and the relative position was fixed. Then, the virtual and real overlapping registration is completed on the physical model. Pattern recognition technology is used to identify pre-defined markers in the video images before operation. Finally, the registration results are superimposed into the surgical field of vision to guide and remind surgeons.

RESULTS

In this study, the navigation based on augmented reality technology was used in the surgical treatment of 5 cases patients with fibrous dysplasia. The 3D navigation information was displayed in real time in the operative field. The operation was accurate and the postoperative effect was good.

CONCLUSIONS

This paper introduces an effective visual navigation surgical method in treatment with fibrous dysplasia. The augmented-reality based navigation system achieves individualized precise treatment by displaying 3D navigation directly in the surgical field. It is an effective auxiliary method for future research on craniofacial surgery.

A Novel Precise Optical Navigation System for Craniomaxillofacial Surgery Registered With an Occlusal Splint

BACKGROUND

An augmented reality tool allows visual tracking of real anatomical structures and superimposing virtual images, so it can be used for navigation of important structures during surgery.

OBJECTIVES

The authors have developed a new occlusal splint-based optical navigation system for craniomaxillofacial surgery. In this study, the authors aim to measure the accuracy of the system and further analyze the main factors influencing precision.

METHODS

Ten beagle dogs were selected and a three-dimensional model was established through computed tomography scanning, dental model making, and laser scanning, and then registration was performed according to the tooth marking points. The bilateral mandibular osteotomy was performed on Beagle dogs under navigation system based on the occlusal splint. The left side was taken to compare the deviation between the preoperative plan and the surgical results, and the accuracy of distance and angle and the stability of the system were analyzed.

RESULTS

The average position deviation between the preoperative design and intraoperative navigation was: 0.01 ± 0.73 mm on the lateral height of the mandibular ramus, 0.26 ± 0.57 mm on the inner height of the mandibular ramus, and 0.20 ± 0.51 mm on the osteotomy length. The average angle deviation is 0.94° ± 1.38° on the angle between the mandibular osteotomy plane and ramus plane and 0.66° ± 0.97° on the angle of the retained mandibular angle. And most of the data showed good consistency.

CONCLUSIONS

In summary, the accuracy of the system can meet clinical requirements and can be used as a useful tool to improve the accuracy of craniomaxillofacial surgery.

Augmented reality navigation method for recontouring surgery of craniofacial fibrous dysplasia

The objective of this study is to introduce the application of augmented reality (AR) navigation system developed by the authors in recontouring surgery of craniofacial fibrous dysplasia. Five consecutive patients with craniofacial fibrous dysplasia were enrolled. Through three-dimensional (3D) simulation, a virtual plan was designed to reconstruct the normal anatomical contour of the deformed region. Surgical recontouring was achieved with the assistance of the AR navigation system. The accuracy of the surgical procedure was assessed by superimposing the post-operative 3D craniomaxillofacial model onto the virtual plan. The pre-operative preparation time and operation time were also counted. In all patients, AR navigation was performed successfully, with a mean ± SD of the errors of 1.442 ± 0.234 mm. The operative time of the patients ranged from 60 to 80 min. The pre-operative preparation time was 20 min for each patient. All the patients showed uneventful healing without any complications, in addition to satisfaction with the post-operative aesthetics. Using our AR navigation system in recontouring surgery can provide surgeons with a comprehensive and intuitive view of the recontouring border, as well as the depth, in real time. This method could improve the efficiency and safety of craniofacial fibrous dysplasia recontouring procedures.

Augmented Reality with HoloLens® in Parotid Tumor Surgery: A Prospective Feasibility Study

INTRODUCTION

Augmented reality can improve planning and execution of surgical procedures. Head-mounted devices such as the HoloLens® (Microsoft, Redmond, WA, USA) are particularly suitable to achieve these aims because they are controlled by hand gestures and enable contactless handling in a sterile environment.

OBJECTIVES

So far, these systems have not yet found their way into the operating room for surgery of the parotid gland. This study explored the feasibility and accuracy of augmented reality-assisted parotid surgery.

METHODS

2D MRI holographic images were created, and 3D holograms were reconstructed from MRI DICOM files and made visible via the HoloLens. 2D MRI slices were scrolled through, 3D images were rotated, and 3D structures were shown and hidden only using hand gestures. The 3D model and the patient were aligned manually.

RESULTS

The use of augmented reality with the HoloLens in parotic surgery was feasible. Gestures were recognized correctly. Mean accuracy of superimposition of the holographic model and patient's anatomy was 1.3 cm. Highly significant differences were seen in position error of registration between central and peripheral structures (p = 0.0059), with a least deviation of 10.9 mm (centrally) and highest deviation for the peripheral parts (19.6-mm deviation).

CONCLUSION

This pilot study offers a first proof of concept of the clinical feasibility of the HoloLens for parotid tumor surgery. Workflow is not affected, but additional information is provided. The surgical performance could become safer through the navigation-like application of reality-fused 3D holograms, and it improves ergonomics without compromising sterility. Superimposition of the 3D holograms with the surgical field was possible, but further invention is necessary to improve the accuracy.

Augmented reality in craniomaxillofacial surgery: added value and proposed recommendations through a systematic review of the literature

This systematic review provides an overview of augmented reality (AR) and its benefits in craniomaxillofacial surgery in an attempt to answer the question: Is AR beneficial for craniomaxillofacial surgery? This review includes a description of the studies conducted, the systems used and their technical characteristics. The search was performed in four databases: PubMed, Cochrane Library, Embase, and Web of Science. All journal articles published during the past 11 years related to AR, mixed reality, craniomaxillofacial, and surgery were considered in this study. From a total of 7067 articles identified using AR- and surgery-related keywords, 39 articles were finally selected. Based on these articles, a classification of study types, surgery types, devices used, metrics reported, and benefits were collected. The findings of this review indicate that AR could provide various benefits, addressing the challenges of conventional navigation systems, such as hand-eye coordination and depth perception. However, three main concerns were raised while performing this study: (1) it is complicated to aggregate the metrics reported in the articles, (2) it is difficult to obtain statistical value from the current studies, and (3) user evaluation studies are lacking. This article concludes with recommendations for future studies by addressing the latter points.