Navigation of Fluorescence Cameras during Soft Tissue Surgery-Is it Possible to Use a Single Navigation Setup for Various Open and Laparoscopic Urological Surgery Applications?

Visual extended reality tools in image-guided surgery in urology: a systematic review

PURPOSE

The aim of this systematic review is to assess the clinical implications of employing various Extended Reality (XR) tools for image guidance in urological surgery.

METHODS

In June 2023, a systematic electronic literature search was conducted using the Medline database (via PubMed), Embase (via Ovid), Scopus, and Web of Science. The search strategy was designed based on the PICO (Patients, Intervention, Comparison, Outcome) criteria. Study protocol was registered on PROSPERO (registry number CRD42023449025). We incorporated retrospective and prospective comparative studies, along with single-arm studies, which provided information on the use of XR, Mixed Reality (MR), Augmented Reality (AR), and Virtual Reality (VR) in urological surgical procedures. Studies that were not written in English, non-original investigations, and those involving experimental research on animals or cadavers were excluded from our analysis. The quality assessment of comparative and cohort studies was conducted utilizing the Newcastle-Ottawa scale, whilst for randomized controlled trials (RCTs), the Jadad scale was adopted. The level of evidence for each study was determined based on the guidelines provided by the Oxford Centre for Evidence-Based Medicine.

RESULTS

The initial electronic search yielded 1,803 papers after removing duplicates. Among these, 58 publications underwent a comprehensive review, leading to the inclusion of 40 studies that met the specified criteria for analysis. 11, 20 and 9 studies tested XR on prostate cancer, kidney cancer and miscellaneous, including bladder cancer and lithiasis surgeries, respectively. Focusing on the different technologies 20, 15 and 5 explored the potential of VR, AR and MR. The majority of the included studies (i.e., 22) were prospective non-randomized, whilst 7 and 11 were RCT and retrospective studies respectively. The included studies that revealed how these new tools can be useful both in preoperative and intraoperative setting for a tailored surgical approach.

CONCLUSIONS

AR, VR and MR techniques have emerged as highly effective new tools for image-guided surgery, especially for urologic oncology. Nevertheless, the complete clinical advantages of these innovations are still in the process of evaluation.

The current status and future prospects for molecular imaging-guided precision surgery

Molecular imaging technologies are increasingly used to diagnose, monitor, and guide treatment of i.e., cancer. In this review, the current status and future prospects of the use of molecular imaging as an instrument to help realize precision surgery is addressed with focus on the main components that form the conceptual basis of intraoperative molecular imaging. Paramount for successful interventions is the relevance and accessibility of surgical targets. In addition, selection of the correct combination of imaging agents and modalities is critical to visualize both microscopic and bulk disease sites with high affinity and specificity. In this context developments within engineering/imaging physics continue to drive the growth of image-guided surgery. Particularly important herein is enhancement of sensitivity through improved contrast and spatial resolution, features that are critical if sites of cancer involvement are not to be overlooked during surgery. By facilitating the connection between surgical planning and surgical execution, digital surgery technologies such as computer-aided visualization nicely complement these technologies. The complexity of image guidance, combined with the plurality of technologies that are becoming available, also drives the need for evaluation mechanisms that can objectively score the impact that technologies exert on the performance of healthcare professionals and outcome improvement for patients.

How molecular imaging will enable robotic precision surgery : The role of artificial intelligence, augmented reality, and navigation

Molecular imaging is one of the pillars of precision surgery. Its applications range from early diagnostics to therapy planning, execution, and the accurate assessment of outcomes. In particular, molecular imaging solutions are in high demand in minimally invasive surgical strategies, such as the substantially increasing field of robotic surgery. This review aims at connecting the molecular imaging and nuclear medicine community to the rapidly expanding armory of surgical medical devices. Such devices entail technologies ranging from artificial intelligence and computer-aided visualization technologies (software) to innovative molecular imaging modalities and surgical navigation (hardware). We discuss technologies based on their role at different steps of the surgical workflow, i.e., from surgical decision and planning, over to target localization and excision guidance, all the way to (back table) surgical verification. This provides a glimpse of how innovations from the technology fields can realize an exciting future for the molecular imaging and surgery communities.

PET- and SPECT-based navigation strategies to advance procedural accuracy in interventional radiology and image-guided surgery

INTRODUCTION

Nuclear medicine has a crucial role in interventional strategies where a combination between the increasing use of targeted radiotracers and intraprocedural detection modalities enable novel, but often complex, targeted procedures in both the fields of interventional radiology and surgery. 3D navigation approaches could assist the interventional radiologist or surgeon in such complex procedures.

EVIDENCE ACQUISITION

This review aimed to provide a comprehensive overview of the current application of computer-assisted navigation strategies based on nuclear imaging to assist in interventional radiology and image-guided surgery. This work starts with a brief overview of the typical navigation workflow from a technical perspective, which is followed by the different clinical applications organized based on their anatomical organ of interest.

EVIDENCE SYNTHESIS

Although many studies have proven the feasibility of PET- and SPECT-based navigation strategies for various clinical applications in both interventional radiology and surgery, the strategies are spread widely in both navigation workflows and clinical indications, evaluated in small patient groups. Hence, no golden standard has yet been established.

CONCLUSIONS

Despite that the clinical outcome is yet to be determined in large patient cohorts, navigation seems to be a promising technology to translate nuclear medicine findings, provided by PET- and SPECT-based molecular imaging, to the intervention and operating room. Interventional Nuclear Medicine (iNM) has an exciting future to come using both PET- and SPECT-based navigation.

Interventional nuclear medicine: a focus on radioguided intervention and surgery

Within interventional nuclear medicine (iNM) a prominent role is allocated for the sub-discipline of radioguided surgery. Unique for this discipline is the fact that an increasing number of clinical indications (e.g. lymphatic mapping, local tumor demarcation and/or tumor receptor targeted applications) have been adopted into routine care. The clinical integration is further strengthened by technical innovations in chemistry and engineering that enhance the translational potential of radioguided procedures in iNM. Together, these features not only ensure ongoing expansion of iNM but also warrant a lasting clinical impact for the sub-discipline of radioguided surgery.

A review on the applications of virtual reality, augmented reality and mixed reality in surgical simulation: an extension to different kinds of surgery

Background: Research proves that the apprenticeship model, which is the gold standard for training surgical residents, is obsolete. For that reason, there is a continuing effort toward the development of high-fidelity surgical simulators to replace the apprenticeship model. Applying Virtual Reality Augmented Reality (AR) and Mixed Reality (MR) in surgical simulators increases the fidelity, level of immersion and overall experience of these simulators.Areas covered: The objective of this review is to provide a comprehensive overview of the application of VR, AR and MR for distinct surgical disciplines, including maxillofacial surgery and neurosurgery. The current developments in these areas, as well as potential future directions, are discussed.Expert opinion: The key components for incorporating VR into surgical simulators are visual and haptic rendering. These components ensure that the user is completely immersed in the virtual environment and can interact in the same way as in the physical world. The key components for the application of AR and MR into surgical simulators include the tracking system as well as the visual rendering. The advantages of these surgical simulators are the ability to perform user evaluations and increase the training frequency of surgical residents.

Extending the Hybrid Surgical Guidance Concept With Freehand Fluorescence Tomography

Within image-guided surgery, 'hybrid' guidance technologies have been used to integrate the complementary features of radioactive guidance and fluorescence guidance. Here, we explore how the generation of a novel freehand fluorescence (fhFluo) imaging approach complements freehand SPECT (fhSPECT) in a hybrid setup. Near-infrared optical tracking was used to register the position and the orientation of a hybrid opto-nuclear detection probe while recording its readings. Dedicated look-up table models were used for 3D reconstruction. In phantom and excised tissue settings (i.e., flat-surface human skin explants), fhSPECT and fhFluo were investigated for image resolution and in-tissue signal penetration. Finally, the combined potential of these freehand technologies was evaluated on prostate and lymph node specimens of prostate cancer patients receiving prostatectomy and sentinel lymph node dissection (tracers: indocyanine green (ICG) +^99m Tc-nanocolloid or ICG-^99mTc-nanocolloid). After hardware and software integration, the hybrid setup created 3D nuclear and fluorescence tomography scans. The imaging resolution of fhFluo (1 mm) was superior to that of fhSPECT (6 mm). Fluorescence modalities were confined to a maximum depth of 0.5 cm, while nuclear modalities were usable at all evaluated depths (<2 cm). Both fhSPECT and fhFluo enabled augmented- and virtual-reality navigation toward segmented image hotspots, including relative hotspot quantification with an accuracy of 3.9% and 4.1%. Imaging in surgical specimens confirmed these trends (fhSPECT: in-depth detectability, low resolution, and fhFluo: superior resolution, superficial detectability). Overall, when radioactive and fluorescent tracer signatures are used, fhFluo has complementary value to fhSPECT. Combined the freehand technologies render a unique hybrid imaging and navigation modality.

Recent advances in nuclear and hybrid detection modalities for image-guided surgery

Introduction: Radioguided surgery is an ever-evolving part of nuclear medicine. In fact, this nuclear medicine sub-discipline actively bridges non-invasive molecular imaging with surgical care. Next to relying on the availability of radio- and bimodal-tracers, the success of radioguided surgery is for a large part dependent on the imaging modalities and imaging concepts available for the surgical setting. With this review, we have aimed to provide a comprehensive update of the most recent advances in the field. Areas covered: We have made an attempt to cover all aspects of radioguided surgery: 1) the use of radioisotopes that emit γ, β⁺, and/or β^- radiation, 2) hardware developments ranging from probes to 2D cameras and even the use of advanced 3D interventional imaging solutions, and 3) multiplexing solutions such as dual-isotope detection or combined radionuclear and optical detection. Expert opinion: Technical refinements in the field of radioguided surgery should continue to focus on supporting its implementation in the increasingly complex minimally invasive surgical setting, e.g. by accommodating robot-assisted laparoscopic surgery. In addition, hybrid concepts that integrate the use of radioisotopes with other image-guided surgery modalities such as fluorescence or ultrasound are likely to expand in the future.

Systematic review of augmented reality in urological interventions: the evidences of an impact on surgical outcomes are yet to come

PURPOSE

To perform a systematic literature review on the clinical impact of augmented reality (AR) for urological interventions.

METHODS

As of June 21, 2018, systematic literature review was performed via Medline, Embase and Cochrane databases in accordance with the PRISMA guidelines and registered at PROSPERO (CRD42018102194). Only full text articles in English were included, without time restrictions. Articles were considered if they reported on the use of AR during urological intervention and the impact on the surgical outcomes. The risk of bias and the quality of each study included were independently assessed using the standard Cochrane Collaboration risk of bias tool and the Risk Of Bias In Non-randomised Studies-of Interventions Tool (ROBINS-I).

RESULTS

131 articles were identified. 102 remained after duplicate removal and were critically reviewed for evidence synthesis. 20 studies reporting on the outcomes of the use of AR during urological interventions in a clinical setting were considered. Given the mostly non-comparative design of the studies identified, the evidence synthesis was performed in a descriptive and narrative manner. Only one comparative study was found, with the remaining 19 items being single-arm observational studies. Based on the existing evidence, we are unable to state that AR improves the outcomes of urological interventions. The major limitation of AR-assisted surgery is inaccuracy in registration, translating into a poor navigation precision.

CONCLUSIONS

To date, there is limited evidence showing superior therapeutic benefits of AR-guided surgery when compared with the conventional surgical approach to the respective disease.

Augmented reality in open surgery

Augmented reality (AR) has been successfully providing surgeons an extensive visual information of surgical anatomy to assist them throughout the procedure. AR allows surgeons to view surgical field through the superimposed 3D virtual model of anatomical details. However, open surgery presents new challenges. This study provides a comprehensive overview of the available literature regarding the use of AR in open surgery, both in clinical and simulated settings. In this way, we aim to analyze the current trends and solutions to help developers and end/users discuss and understand benefits and shortcomings of these systems in open surgery. We performed a PubMed search of the available literature updated to January 2018 using the terms (1) "augmented reality" AND "open surgery", (2) "augmented reality" AND "surgery" NOT "laparoscopic" NOT "laparoscope" NOT "robotic", (3) "mixed reality" AND "open surgery", (4) "mixed reality" AND "surgery" NOT "laparoscopic" NOT "laparoscope" NOT "robotic". The aspects evaluated were the following: real data source, virtual data source, visualization processing modality, tracking modality, registration technique, and AR display type. The initial search yielded 502 studies. After removing the duplicates and by reading abstracts, a total of 13 relevant studies were chosen. In 1 out of 13 studies, in vitro experiments were performed, while the rest of the studies were carried out in a clinical setting including pancreatic, hepatobiliary, and urogenital surgeries. AR system in open surgery appears as a versatile and reliable tool in the operating room. However, some technological limitations need to be addressed before implementing it into the routine practice.

Navigating surgical fluorescence cameras using near-infrared optical tracking

Fluorescence guidance facilitates real-time intraoperative visualization of the tissue of interest. However, due to attenuation, the application of fluorescence guidance is restricted to superficial lesions. To overcome this shortcoming, we have previously applied three-dimensional surgical navigation to position the fluorescence camera in reach of the superficial fluorescent signal. Unfortunately, in open surgery, the near-infrared (NIR) optical tracking system (OTS) used for navigation also induced an interference during NIR fluorescence imaging. In an attempt to support future implementation of navigated fluorescence cameras, different aspects of this interference were characterized and solutions were sought after. Two commercial fluorescence cameras for open surgery were studied in (surgical) phantom and human tissue setups using two different NIR OTSs and one OTS simulating light-emitting diode setup. Following the outcome of these measurements, OTS settings were optimized. Measurements indicated the OTS interference was caused by: (1) spectral overlap between the OTS light and camera, (2) OTS light intensity, (3) OTS duty cycle, (4) OTS frequency, (5) fluorescence camera frequency, and (6) fluorescence camera sensitivity. By optimizing points 2 to 4, navigation of fluorescence cameras during open surgery could be facilitated. Optimization of the OTS and camera compatibility can be used to support navigated fluorescence guidance concepts.