Head-up display assisted endoscopic lumbar discectomy-A technical note

Visualization, registration and tracking techniques for augmented reality guided surgery: a review

Augmented reality (AR) surgical navigation has developed rapidly in recent years. This paper reviews and analyzes the visualization, registration, and tracking techniques used in AR surgical navigation systems, as well as the application of these AR systems in different surgical fields. The types of AR visualization are divided into two categories ofin situvisualization and nonin situvisualization. The rendering contents of AR visualization are various. The registration methods include manual registration, point-based registration, surface registration, marker-based registration, and calibration-based registration. The tracking methods consist of self-localization, tracking with integrated cameras, external tracking, and hybrid tracking. Moreover, we describe the applications of AR in surgical fields. However, most AR applications were evaluated through model experiments and animal experiments, and there are relatively few clinical experiments, indicating that the current AR navigation methods are still in the early stage of development. Finally, we summarize the contributions and challenges of AR in the surgical fields, as well as the future development trend. Despite the fact that AR-guided surgery has not yet reached clinical maturity, we believe that if the current development trend continues, it will soon reveal its clinical utility.

A Comparative Analysis of Ergonomic Risk Utilizing the 4K-3D Exoscope Versus Standard Operating Microscope for Male Fertility Microsurgery

OBJECTIVE

To stratify ergonomic risk in a urologic microsurgeon using the 4K-3D exoscope versus the operating microscope (OM) with wearable technology.

METHODS

The surgeon was calibrated with wearable sensor inertial measurement units (IMUs) on the head and upper arms. Each inertial measurement units contained an accelerometer, magnetometer, and gyroscope to measure surgeon joint angle change during microscopic procedures for male fertility. The validated modified rapid upper limb assessment was used to determine the proportion of time spent in ranges of risk. Categories 1-4 were assigned for the head and upper extremities (4= highest ergonomic risk). Chi-squared analysis was used to analyze differences in proportions.

RESULTS

A total of 500 and 479 minutes from 4K-3D exoscope and OM guided surgeries were analyzed. The 4K-3D exoscope significantly favored upper arm category 1 positioning compared to the OM (56.2% vs 37.7%; P < .0001). The OM exposed the surgeon to higher category 3 positioning (14.6% vs 1.6%; P <.0001). More time was spent with the neck "extended" using the 4K-3D exoscope (51.8% vs 19.5%; P < .0001) with 67% of neck extension between 0-10° (category 1). Overall, more time was spent with the neck in risk group 1-2 with the OM (P < .0001).

CONCLUSION

The 4K-3D exoscope offers favorable ergonomic positioning for the upper extremities which may reduce work stress-related injury. More operative time was spent with the neck in mild extension with 4K-3D exoscope utilization. However, the OM favored longer operative times in low-risk neck ergonomic positions.

Review and Future/Potential Application of Mixed Reality Technology in Orthopaedic Oncology

In orthopaedic oncology, surgical planning and intraoperative execution errors may result in positive tumor resection margins that increase the risk of local recurrence and adversely affect patients’ survival. Computer navigation and 3D-printed resection guides have been reported to address surgical inaccuracy by replicating the surgical plans in complex cases. However, limitations include surgeons’ attention shift from the operative field to view the navigation monitor and expensive navigation facilities in computer navigation surgery. Practical concerns are lacking real-time visual feedback of preoperative images and the lead-time in manufacturing 3D-printed objects. Mixed Reality (MR) is a technology of merging real and virtual worlds to produce new environments with enhanced visualizations, where physical and digital objects coexist and allow users to interact with both in real-time. The unique MR features of enhanced medical images visualization and interaction with holograms allow surgeons real-time and on-demand medical information and remote assistance in their immediate working environment. Early application of MR technology has been reported in surgical procedures. Its role is unclear in orthopaedic oncology. This review aims to provide orthopaedic tumor surgeons with up-to-date knowledge of the emerging MR technology. The paper presents its essential features and clinical workflow, reviews the current literature and potential clinical applications, and discusses the limitations and future development in orthopaedic oncology. The emerging MR technology adds a new dimension to digital assistive tools with a more accessible and less costly alternative in orthopaedic oncology. The MR head-mounted display and hand-free control may achieve clinical point-of-care inside or outside the operating room and improve service efficiency and patient safety. However, lacking an accurate hologram-to-patient matching, an MR platform dedicated to orthopaedic oncology, and clinical results may hinder its wide adoption. Industry-academic partnerships are essential to advance the technology with its clinical role determined through future clinical studies.

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Utility of optical see-through head mounted displays in augmented reality-assisted surgery: A systematic review

This article presents a systematic review of optical see-through head mounted display (OST-HMD) usage in augmented reality (AR) surgery applications from 2013 to 2020. Articles were categorised by: OST-HMD device, surgical speciality, surgical application context, visualisation content, experimental design and evaluation, accuracy and human factors of human-computer interaction. 91 articles fulfilled all inclusion criteria. Some clear trends emerge. The Microsoft HoloLens increasingly dominates the field, with orthopaedic surgery being the most popular application (28.6%). By far the most common surgical context is surgical guidance (n=58) and segmented preoperative models dominate visualisation (n=40). Experiments mainly involve phantoms (n=43) or system setup (n=21), with patient case studies ranking third (n=19), reflecting the comparative infancy of the field. Experiments cover issues from registration to perception with very different accuracy results. Human factors emerge as significant to OST-HMD utility. Some factors are addressed by the systems proposed, such as attention shift away from the surgical site and mental mapping of 2D images to 3D patient anatomy. Other persistent human factors remain or are caused by OST-HMD solutions, including ease of use, comfort and spatial perception issues. The significant upward trend in published articles is clear, but such devices are not yet established in the operating room and clinical studies showing benefit are lacking. A focused effort addressing technical registration and perceptual factors in the lab coupled with design that incorporates human factors considerations to solve clear clinical problems should ensure that the significant current research efforts will succeed.

XR (Extended Reality: Virtual Reality, Augmented Reality, Mixed Reality) Technology in Spine Medicine: Status Quo and Quo Vadis

In recent years, with the rapid advancement and consumerization of virtual reality, augmented reality, mixed reality, and extended reality (XR) technology, the use of XR technology in spine medicine has also become increasingly popular. The rising use of XR technology in spine medicine has also been accelerated by the recent wave of digital transformation (i.e., case-specific three-dimensional medical images and holograms, wearable sensors, video cameras, fifth generation, artificial intelligence, and head-mounted displays), and further accelerated by the COVID-19 pandemic and the increase in minimally invasive spine surgery. The COVID-19 pandemic has a negative impact on society, but positive impacts can also be expected, including the continued spread and adoption of telemedicine services (i.e., tele-education, tele-surgery, tele-rehabilitation) that promote digital transformation. The purpose of this narrative review is to describe the accelerators of XR (VR, AR, MR) technology in spine medicine and then to provide a comprehensive review of the use of XR technology in spine medicine, including surgery, consultation, education, and rehabilitation, as well as to identify its limitations and future perspectives (status quo and quo vadis).

Augmented Reality in Spinal Surgery: Highlights From Augmented Reality Lectures at the Emerging Technologies Annual Meetings

Introduction

Augmented reality (AR) is an advanced technology and emerging field that has been adopted into spine surgery to enhance care and outcomes. AR superimposes a three-dimensional computer-generated image over the normal anatomy of interest in order to facilitate visualization of deep structures without the ability to directly see them.

Objective

To summarize the latest literature and highlight AR from the annual “Spinal Navigation, Emerging Technologies and Systems Integration” meeting lectures presented by the Seattle Science Foundation (SSF) on the development and use of augmented reality in spinal surgery. 

Methods

 We performed a comprehensive literature review from 2016 to 2020 on PubMed to correlate with lectures given at the annual “Emerging Technologies” conferences. After the exclusion of papers that concerned non-spine surgery specialties, a total of 54 papers concerning AR in spinal applications were found. The articles were then categorized by content and focus.

Results

The 54 papers were divided into six major focused topics: training, proof of concept, feasibility and usability, clinical evaluation, state of technology, and nonsurgical applications. The greatest number of papers were published during 2020. Each paper discussed varied topics such as patient rehabilitation, proof of concept, workflow, applications in neurological and orthopedic spine surgery, and outcomes data.

Conclusions

The recent literature and SSF lectures on AR provide a solid base and demonstrate the emergence of an advanced technology that offers a platform for an advantageous technique that is superior, in that it allows the operating surgeon to focus directly on the patient rather than a guidance screen.

A New Technique that Combines Navigation-Assisted Lateral Interbody Fusion and Percutaneous Placement of Pedicle Screws in the Lateral Decubitus Position with the Surgeon Using Wearable Smart Glasses: A Small Case Series and Technical Note

BACKGROUND

We describe a new technique that combines navigation-assisted extreme lateral interbody fusion (NALIF) and percutaneous placement of pedicle screws in the lateral decubitus position with the surgeon using wearable smart glasses.

METHODS

We explain our method for nonfluoroscopic NALIF and single-position (SP)- percutaneous pedicle screw (PPS) surgery for patients with degenerative lumbar diseases using wearable smart glasses. The wearable smart glasses provide a semitransparent overlay of the navigation information onto the image seen through the lenses. This technique does not require fluoroscopy during lateral interbody fusion or PPS insertion. It is convenient because it does not require a Jamshidi needle or guidewire when inserting PPSs.

RESULTS

Using this method, the surgeon can glance at the 3-dimensional images on the wearable smart glasses while still viewing the operation field. A review of 24 cases yielded an average operation time of 89.5 ± 16.4 minutes and 66.7 ± 67.0 mL of blood loss, without any severe intra- or postoperative complications.

CONCLUSIONS

Nonfluoroscopic NALIF and SP-PPS placement surgery is a safe and effective means for implanting cages and PPSs in this minimally invasive approach without compromising the results. Although further investigations are needed, the wearable smart glasses may be a useful surgical aid when performing NALIF and SP-PPS placement in patients with degenerative lumbar diseases.

Smart glasses display device for fluoroscopically guided minimally invasive spinal instrumentation surgery: a preliminary study

OBJECTIVE

Most surgeons are forced to turn their heads away from the surgical field to see various intraoperative support monitors. These movements may result in inconvenience to surgeons and lead to technical difficulties and potential errors. Wearable devices that can be attached to smart glasses or any glasses are novel visualization tools providing an alternative screen in front of the user's eyes, allowing surgeons to keep their attention focused on the operative task without taking their eyes off the surgical field. The aim of the present study was to examine the feasibility of using glasses equipped with a wearable display device that transmits display monitor data during fluoroscopically guided minimally invasive spinal instrumentation surgery.

METHODS

In this pilot prospective randomized study, 20 consecutively enrolled patients who underwent single-segment posterior lumbar interbody fusion (PLIF) at L5-S1 performed using the percutaneous pedicle screw technique were randomly divided into two groups, a group for which the surgeon used a wearable display device attached to regular glasses while performing surgery (smart glasses group) and a group for which the surgeon did not use such a device (nonglasses group). Real-time intraoperative fluoroscopic images were wirelessly transmitted to the display device attached to the surgeon's glasses. The number of head turns performed by the surgeon to view the standard fluoroscopic monitor during procedures and the operative time, estimated blood loss, radiation exposure time, screw placement accuracy, and intraoperative complication rate were evaluated for comparison between the two groups.

RESULTS

The number of surgeon head turns to view the fluoroscopic monitor in the smart glasses group was 0.10 ± 0.31 times, which was significantly fewer than the head turns in the nonglasses group (82.4 ± 32.5 times; p < 0.001). The operative and radiation exposure times in the smart glasses group were shorter than those in the nonglasses group (operative time 100.2 ± 10.4 vs 105.5 ± 14.6 minutes, radiation exposure time 38.6 ± 6.6 vs 41.8 ± 16.1 seconds, respectively), although the differences were not significant. Postoperative CT showed one screw perforation in the nonglasses group, and no intraoperative complications were observed in either group.

CONCLUSIONS

This is, to the authors' knowledge, the first report on the feasibility of using this wearable display device attached to glasses for fluoroscopically guided minimally invasive spinal instrumentation surgery. Smart glasses display devices such as this one may be a valid option to facilitate better concentration on operative tasks by improving ergonomic efficiency during surgery.