Augmented reality-based navigation system for wrist arthroscopy: feasibility

The application of extended reality technology-assisted intraoperative navigation in orthopedic surgery

Extended reality (XR) technology refers to any situation where real-world objects are enhanced with computer technology, including virtual reality, augmented reality, and mixed reality. Augmented reality and mixed reality technologies have been widely applied in orthopedic clinical practice, including in teaching, preoperative planning, intraoperative navigation, and surgical outcome evaluation. The primary goal of this narrative review is to summarize the effectiveness and superiority of XR-technology-assisted intraoperative navigation in the fields of trauma, joint, spine, and bone tumor surgery, as well as to discuss the current shortcomings in intraoperative navigation applications. We reviewed titles of more than 200 studies obtained from PubMed with the following search terms: extended reality, mixed reality, augmented reality, virtual reality, intraoperative navigation, and orthopedic surgery; of those 200 studies, 69 related papers were selected for abstract review. Finally, the full text of 55 studies was analyzed and reviewed. They were classified into four groups-trauma, joint, spine, and bone tumor surgery-according to their content. Most of studies that we reviewed showed that XR-technology-assisted intraoperative navigation can effectively improve the accuracy of implant placement, such as that of screws and prostheses, reduce postoperative complications caused by inaccurate implantation, facilitate the achievement of tumor-free surgical margins, shorten the surgical duration, reduce radiation exposure for patients and surgeons, minimize further damage caused by the need for visual exposure during surgery, and provide richer and more efficient intraoperative communication, thereby facilitating academic exchange, medical assistance, and the implementation of remote healthcare.

Augmented reality-based surgical guidance for wrist arthroscopy with bone-shift compensation

BACKGROUND AND OBJECTIVES

Intraoperative joint condition is different from preoperative CT/MR due to the motion applied during surgery, inducing an inaccurate approach to surgical targets. This study aims to provide real-time augmented reality (AR)-based surgical guidance for wrist arthroscopy based on a bone-shift model through an in vivo computed tomography (CT) study.

METHODS

To accurately visualize concealed wrist bones on the intra-articular arthroscopic image, we propose a surgical guidance system with a novel bone-shift compensation method using noninvasive fiducial markers. First, to measure the effect of traction during surgery, two noninvasive fiducial markers were attached before surgery. In addition, two virtual link models connecting the wrist bones were implemented. When wrist traction occurs during the operation, the movement of the fiducial marker is measured, and bone-shift compensation is applied to move the virtual links in the direction of the traction. The proposed bone-shift compensation method was verified with the in vivo CT data of 10 participants. Finally, to introduce AR, camera calibration for the arthroscope parameters was performed, and a patient-specific template was used for registration between the patient and the wrist bone model. As a result, a virtual bone model with three-dimensional information could be accurately projected on a two-dimensional arthroscopic image plane.

RESULTS

The proposed method was possible to estimate the position of wrist bone in the traction state with an accuracy of 1.4 mm margin. After bone-shift compensation was applied, the target point error was reduced by 33.6% in lunate, 63.3% in capitate, 55.0% in scaphoid, and 74.8% in trapezoid than those in preoperative wrist CT. In addition, a phantom experiment was introduced simulating the real surgical environment. AR display allowed to expand the field of view (FOV) of the arthroscope and helped in visualizing the anatomical structures around the bones.

CONCLUSIONS

This study demonstrated the successful handling of AR error caused by wrist traction using the proposed method. In addition, the method allowed accurate AR visualization of the concealed bones and expansion of the limited FOV of the arthroscope. The proposed bone-shift compensation can also be applied to other joints, such as the knees or shoulders, by representing their bone movements using corresponding virtual links. In addition, the movement of the joint skin during surgery can be measured using noninvasive fiducial markers in the same manner as that used for the wrist joint.

Simulation in Hand Surgery: A Literature Review

BACKGROUND

Due to duty hour regulations, patient safety and inadequate operative time simulation have become a necessary part of surgical education and training in residency. Currently, there is no formal adoption of simulators for the use of surgical education or assessment in hand surgery. This literature review analyzes that the simulation techniques established thus far in hand surgery.

METHODS

A comprehensive literature search was performed on PubMed. Search results were filtered by title and abstract to isolate articles that were relevant to simulation in hand surgery. Articles that were nonspecific to the hand, non-English and cadaveric were excluded. Additional articles were identified through references from the initial search.

RESULTS

A total of 1192 articles were yielded from the initial query. After the application of the inclusion criteria, this was narrowed down to 28 articles. Another 8 additional articles were excluded as they did not pertain to the hand although the simulators could be adapted for hand surgery. A total of 20 articles were included in this study.

CONCLUSIONS

Surgical simulation is a growing and essential field of surgical education. Simulators in hand surgery are limited and require further research and validation. Like other surgical subspecialties, hand surgery may benefit from the adoption of an official simulation curriculum for the assessment of residents and enhancement of technical skills.

Experimental pilot study for augmented reality-enhanced elbow arthroscopy

The purpose of this study was to develop and evaluate a novel elbow arthroscopy system with superimposed bone and nerve visualization using preoperative computed tomography (CT) and magnetic resonance imaging (MRI) data. We obtained bone and nerve segmentation data by CT and MRI, respectively, of the elbow of a healthy human volunteer and cadaveric Japanese monkey. A life size 3-dimensional (3D) model of human organs and frame was constructed using a stereo-lithographic 3D printer. Elbow arthroscopy was performed using the elbow of a cadaveric Japanese monkey. The augmented reality (AR) range of error during rotation of arthroscopy was examined at 20 mm scope-object distances. We successfully performed AR arthroscopy using the life-size 3D elbow model and the elbow of the cadaveric Japanese monkey by making anteromedial and posterior portals. The target registration error was 1.63 ± 0.49 mm (range 1-2.7 mm) with respect to the rotation angle of the lens cylinder from 40° to - 40°. We attained reasonable accuracy and demonstrated the operation of the designed system. Given the multiple applications of AR-enhanced arthroscopic visualization, it has the potential to be a next-generation technology for arthroscopy. This technique will contribute to the reduction of serious complications associated with elbow arthroscopy.

The New Frontier: A Review of Augmented Reality and Virtual Reality in Plastic Surgery

Mixed reality, a blending of the physical and digital worlds, can enhance the surgical experience, leading to greater precision, efficiency, and improved outcomes. Various studies across different disciplines have reported encouraging results using mixed reality technologies, such as augmented and virtual reality. To provide a better understanding of the applications and limitations of this technology in plastic surgery, we performed a systematic review of the literature in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The initial query of the National Center for Biotechnology Information database yielded 2544 results, and only 46 articles met our inclusion criteria. The majority of studies were in the field of craniofacial surgery, and uses of mixed reality included preoperative planning, intraoperative guides, and education of surgical trainees. A deeper understanding of mixed reality technologies may promote its integration and also help inspire new and creative applications in healthcare.

Augmented Reality in Orthopedics: Current State and Future Directions

Augmented reality (AR) comprises special hardware and software, which is used in order to offer computer-processed imaging data to the surgeon in real time, so that real-life objects are combined with computer-generated images. AR technology has recently gained increasing interest in the surgical practice. Preclinical research has provided substantial evidence that AR might be a useful tool for intra-operative guidance and decision-making. AR has been applied to a wide spectrum of orthopedic procedures, such as tumor resection, fracture fixation, arthroscopy, and component's alignment in total joint arthroplasty. The present study aimed to summarize the current state of the application of AR in orthopedics, in preclinical and clinical level, providing future directions and perspectives concerning potential further benefits from this technology.

Teaching of distal radius shortening osteotomy: three-dimensional procedural simulator versus bone procedural simulator

In order to facilitate the learning of distal radius shortening osteotomy by junior surgeons, the main assumption was that using a three-dimensional procedural simulator was better than a bone procedural simulator. After viewing a video, ten junior surgeons performed a distal radius shortening osteotomy: five with a bone procedural simulator (Group 1) and five with a three-dimensional procedural simulator (Group 2). All subsequently performed the same surgery on fresh cadaveric bones. The duration of the procedure, shortening of the radius, and the level of osteotomy were significantly better in Group 2. The three-dimensional procedural simulator seems to teach distal radius osteotomy better than a bone model and could be useful in teaching and learning bone surgery of the wrist.

Design and evaluation of a new synthetic wrist procedural simulator (Wristsim®) for training of distal radius fracture fixation by volar plating

Legislation concerning workload of surgical trainees and pressure to reduce learning curves have forced us reconsider surgical training. Our goal was to evaluate a synthetic procedural simulator for teaching open reduction and internal fixation (ORIF) of distal radius fractures (DRF). Twenty surgeons used a synthetic procedural simulator (Wristsim^®) made by 3D printing for ORIF of DRF with a volar plate (Newclip Technics^®). The evaluation consisted of grading the simulator's realism compared to the surgeons' own experience with surgery on cadavers. The Wristsim^® was graded 5.10/10, compared to 8.18/10 for the cadaver specimen for introduction of the plate under pronator quadratus. For fracture reproduction, Wristsim^® scored 6.40/10, with the cadaver specimen scoring 7.15/10. For fracture reduction, Wristsim^® scored 5.62/10, with the cadaver specimen scoring 7.38/10. Plate application was scored 7.05/10 for Wristsim^® and 8.23/10 for the cadaver. Drilling was scored 6.60/10 for the Wristsim^® and 8.23/10 for the cadaver. Screw fixation was scored 7.40/10 for the Wristsim^® and 8.12/10 for the cadaver. Our results demonstrated that Wristsim^® is still inferior to a cadaver specimen for teaching ORIF by volar plating of DRF. A new model of Wristsim^® is being developed that will address shortcomings in pronator quadratus thickness, passive ROM in flexion/extension and bone size.

Comparison between isotropic linear-elastic law and isotropic hyperelastic law in the finite element modeling of the brachial plexus

Augmented reality could help the identification of nerve structures in brachial plexus surgery. The goal of this study was to determine which law of mechanical behavior was more adapted by comparing the results of Hooke's isotropic linear elastic law to those of Ogden's isotropic hyperelastic law, applied to a biomechanical model of the brachial plexus. A model of finite elements was created using the ABAQUS^® from a 3D model of the brachial plexus acquired by segmentation and meshing of MRI images at 0°, 45° and 135° of shoulder abduction of a healthy subject. The offset between the reconstructed model and the deformed model was evaluated quantitatively by the Hausdorff distance and qualitatively by the identification of 3 anatomical landmarks. In every case the Hausdorff distance was shorter with Ogden's law compared to Hooke's law. On a qualitative aspect, the model deformed by Ogden's law followed the concavity of the reconstructed model whereas the model deformed by Hooke's law remained convex. In conclusion, the results of this study demonstrate that the behavior of Ogden's isotropic hyperelastic mechanical model was more adapted to the modeling of the deformations of the brachial plexus.

The use of navigation forces for assessment of wrist arthroscopy skills level

Purpose To provide an efficient learning process, feedback on performance is crucial. In skills laboratories, it is possible to measure the skills and progression of skills of the trainees objectively. This requires metrics that represent the learning curve of the trainee, which were investigated for wrist arthroscopy. The research questions were: What are the forces used by novices during wrist arthroscopy?What aspects of these navigation forces are discriminative for the wrist arthroscopy skills level?Methods A cadaver wrist was mounted in a custom-made distraction device mounted in front of a force platform (ForceTrap). Eleven novices were invited to perform two tasks on the wrist: Insertion of the scope through the 3-4 portal and the hook through the 6R portal, and visualization of the hook in the center of the imageNavigation through the wrist from radial to ulnar with probing and visualization of five predefined landmarksThe second task was repeated 10 times. The absolute force (F abs) and the direction of force were measured. The angle α is defined in the vertical plane, and the angle β in the horizontal plane. Results The median F abs used by novices remained below the force threshold as defined from the expert data (7.3 N). However, the direction of the applied forces by novices in both planes was not consistent with expert data and showed a wider range. Also, there was no improvement after more trials. Conclusion Our study suggests by the absence of a learning curve for the novices and a significant difference between novices and experts that novices can benefit from feedback on the magnitude and direction of forces to improve their performance.