Introduction
Digital technology and computer-assisted applications are being progressively used by the orthopedic fraternity in their day-to-day clinical practice. Imaging technologies like computerized tomography (CT) and magnetic resonance imaging (MRI) have revolutionized and greatly contributed to the precise diagnosis, close monitoring, and accurate treatment of several musculoskeletal disorders and related ailments. Augmented reality (AR) is an integrative technique that, combined with orthopedic applications like diagnosis and treatment interventions, would become a promising tool for orthopedic surgeons. This article reviews the diverse aspects of augmented reality (AR) in present-day orthopedic applications.
What Does Augmented Reality Mean?
Augmented reality (AR) refers to a three-dimensional display of digital technology that superimposes digital information and details onto the real-world environment. It involves overlaying digital images in the real world to enhance and visualize digital details. It is an emerging medicine technique with diverse applications, such as data visualization, preoperative planning, intraoperative management, intraoperative guidance for surgical tools, medical education, and advanced training. In the healthcare domain, augmented reality increases the technical skill and ability of the clinician, surgeon, or healthcare provider by perceiving intuitive medical information through virtual augmentation. AR refers to the augmentation of a real-world environment with detailed virtual information.
How Does Augmented Reality Work?
A wide range of AR systems are being developed with advanced technology and are being implemented at both clinical and preclinical levels. Any AR system primarily consists of three main components. They are:
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Position Tracking System - It monitors the location and the exact orientation of the study object or operative field.
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Display System - It contains a semi-transparent head-mounted or standard display screen to project the real image superimposed on a virtual image. It augments the user’s view through a monitor-based, optical, or video see-through display system.
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Control Software System - This system combines the visual image details and the digital data present in the tracking system for visualization on the display screen. This control software processes and updates the available data faster, providing the clinician with a detailed and accurate real-time image display.
In current clinical practice, some AR systems are supplemented with conventional imaging modalities like CT scans and fluoroscopic images obtained during preoperative procedures. The control software system uses these image inputs and positioning markers to determine the relative object position in the operative field. Augmented reality systems comprise sophisticated hardware and advanced software for offering accurate computer-processed images and virtual data to surgeons in real-time environments so that real-life operational sites or objects can be combined with computer-generated virtual images.
How Is Augmented Reality Used in Orthopedics?
The AR system is greatly used in preoperative diagnosis and surgical interventional procedures in orthopedics. Augmented reality finds its usage in orthopedic surgeries in the following ways:
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Visualizing clinical data like medical images of surgical importance obtained during preoperative and intra-operative procedures.
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It aids in mechanical procedures like insertions of implants or screws, surgical bone-cutting (osteotomies), and correcting musculoskeletal deformities.
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It helps visualize the anatomical structures and rigid relations in augmented real environments.
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In tumor surgeries, augmented reality helps visualize the three-dimensional expansion of the bone tumor, which is a crucial step in proper surgical resection of the malignancies.
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In trauma care, AR systems enable surgeons to visualize preoperative osteointegration plate models and virtually created models simultaneously, which favors the selection of optimal implant models appropriate for the clinical conditions.
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Augmented reality enhances orthopedic surgical training like arthroscopy and advanced education when combined with telemedicine facilities.
What Are the Clinical Implications of AR Systems in Orthopedics?
In recent years, various studies have documented the use of augmented reality (AR) systems in both preclinical orthopedic research and clinical practice. Substantial scientific evidence suggests that AR systems could be a useful and integrative tool in orthopedic applications like preoperative decision-making and intra-operative guidance. Some of the current implications of AR systems in orthopedics are as follows -
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Camera-Augmented C-Arm AR Systems - These are used in various procedures like implant removal and nail, screw, and plate removal aided by fluoroscopy. Augmented reality techniques markedly reduced (nearly half) the number of X-ray shots in these procedures.
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Virtual Interactive Presence (VIP) - It is an interactive AR system where two real-time streaming videos, recorded separately in remote fields, are merged for a single common operational field facilitating interaction in real-time with surgeons in remote healthcare settings. VIP technology is commonly used in performing shoulder arthroscopy procedures. VIP-AR technology is an effective teaching tool for medical students and orthopedic residents. Total shoulder arthroplasty procedures are also performed by combining VIP-AR systems and wearable computing equipment, which provides significant postoperative motion range and considerable pain reduction.
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AR-Hip - Through this AR system, the orthopedic surgeon could view the image of the acetabular cup (of the hip joint) being overlaid on the real operational field through a smartphone display. It enables better visualization of the inclination and anteversion angles of the acetabulum (interior of the hip joint). Successful total hip arthroplasty procedures are performed using AR-HIP systems. In fractures involving the pelvis and acetabulum (hip joint), virtual fracture reduction systems comprising AR-aided templates, personal computers, and video cameras are used. These AR-based reconstruction plates relatively reduce the operative time duration and surgical complexity leading to minimal invasiveness. In spine surgeries, surgical navigation AR systems employs video inputs from multiple cameras, favoring acceptable duration for navigation and offering high accuracy in pedicle screw placement.
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Augmented Reality Computer Assisted Spine Surgery (ARCASS) - Here, a projector and a camera are used to project the three-dimensional (3D) preoperative model of the individual undergoing spinal surgery onto the intraoperative field. This AR-based system reduces operative time and radiation doses to the patients.
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Virtual Protractor With Augmented Reality (VIPAR) - It comprises a tracking camera with a head-mounted display and a marker sheet for three-dimensional visualization of the needle trajectory in percutaneous vertebroplasty procedures. It facilitates surgeons in finding the accurate needle trajectory. AR systems create virtual planes for resection and spinal osteotomy volumes preoperatively during spinal surgeries. These systems, controlled by intraoperative visualization, transfer 3D operational plans to navigation systems through head-up displays in surgical microscopes. Such AR-aided surgeries increase accuracy and safety in individuals undergoing corrective surgery for congenital hemivertebra involving the thoracolumbar spine.
Conclusion
Augmented reality (AR) is widely used in diverse orthopedic interventions like fracture fixations, tumor resection, total joint arthroplasty, and arthroscopic procedures. The clinical implementation of augmented reality systems in diagnostic and orthopedic surgical procedures has shown promising results and encouraging outcomes. The beneficial impact of augmented reality in orthopedics is tremendously expanding, exploring newer and futuristic perspectives.
