Augmented-Reality Surgery to Guide Head and Neck Cancer Re-resection: A Feasibility and Accuracy Study

The Reconstructive Metaverse - Collaboration in Real-Time Shared Mixed Reality Environments for Microsurgical Reconstruction

Plastic surgeons routinely use 3D-models in their clinical practice, from 3D-photography and surface imaging to 3D-segmentations from radiological scans. However, these models continue to be viewed on flattened 2D screens that do not enable an intuitive understanding of 3D-relationships and cause challenges regarding collaboration with colleagues. The Metaverse has been proposed as a new age of applications building on modern Mixed Reality headset technology that allows remote collaboration on virtual 3D-models in a shared physical-virtual space in real-time. We demonstrate the first use of the Metaverse in the context of reconstructive surgery, focusing on preoperative planning discussions and trainee education. Using a HoloLens headset with the Microsoft Mesh application, we performed planning sessions for 4 DIEP-flaps in our reconstructive metaverse on virtual patient-models segmented from routine CT angiography. In these sessions, surgeons discuss perforator anatomy and perforator selection strategies whilst comprehensively assessing the respective models. We demonstrate the workflow for a one-on-one interaction between an attending surgeon and a trainee in a video featuring both viewpoints as seen through the headset. We believe the Metaverse will provide novel opportunities to use the 3D-models that are already created in everyday plastic surgery practice in a more collaborative, immersive, accessible, and educational manner.

Trends and Future Directions in Margin Analysis for Head and Neck Cancers

Margin status in head and neck cancer has important prognostic implications. Currently, resection is based on manual palpation and gross visualization followed by intraoperative specimen or tumor bed-based margin analysis using frozen sections. While generally effective, this protocol has several limitations including margin sampling and close and positive margin re-localization. There is a lack of evidence on the association of use of frozen section analysis with improved survival in head and neck cancer. This article reviews novel technologies in head and neck margin analysis such as 3-dimensional scanning, augmented reality, molecular margins, optical imaging, spectroscopy, and artificial intelligence.

More than meets the eye: Augmented reality in surgical oncology

BACKGROUND AND OBJECTIVES

In the field of surgical oncology, there has been a desire for innovative techniques to improve tumor visualization, resection, and patient outcomes. Augmented reality (AR) technology superimposes digital content onto the real-world environment, enhancing the user's experience by blending digital and physical elements. A thorough examination of AR technology in surgical oncology has yet to be performed.

METHODS

A scoping review of intraoperative AR in surgical oncology was conducted according to the guidelines and recommendations of The Preferred Reporting Items for Systematic Review and Meta-analyzes Extension for Scoping Reviews (PRISMA-ScR) framework. All original articles examining the use of intraoperative AR during surgical management of cancer were included. Exclusion criteria included virtual reality applications only, preoperative use only, fluorescence, AR not specific to surgical oncology, and study design (reviews, commentaries, abstracts).

RESULTS

A total of 2735 articles were identified of which 83 were included. Most studies (52) were performed on animals or phantom models, while the remaining included patients. A total of 1112 intraoperative AR surgical cases were performed across the studies. The most common anatomic site was brain (20 articles), followed by liver (16), renal (9), and head and neck (8). AR was most often used for intraoperative navigation or anatomic visualization of tumors or critical structures but was also used to identify osteotomy or craniotomy planes.

CONCLUSIONS

AR technology has been applied across the field of surgical oncology to aid in localization and resection of tumors.

Perspectives in Using Multiple Flaps Reconstructions for Advanced Head and Neck Tumors (Scoping Review)

Background and Objectives: Patients with advanced head and neck tumors require salvage surgery as a last resort. These extensive surgeries pose the challenge of complex reconstructions. The head and neck surgeon undertaking such complex cases needs to master different flaps. The team managing these patients needs input from various specialists, along with otorhinolaryngologists, plastic surgeons, maxillofacial surgeons, vascular surgeons, experienced radiologists, dedicated pathologists, oncologists and radiation therapists. We focus on the optimum solution between oncologic resections and the future quality of life of patients and overall survival. Each complex case requires a personalized medicine approach. This scoping review aims to assess the efficacy and outcomes of complex reconstructions using various flaps for head and neck tumors, with a focus on free flaps and emerging techniques. Materials and Methods: A systematic search of the literature was conducted following PRISMA guidelines, resulting in the inclusion of 44 articles that met the predefined criteria in the last 10 years. Results: The included studies encompassed diverse patient populations and evaluated various surgical techniques, outcomes, complications, and advancements in head and neck reconstruction. The review identified a variety of flaps utilized in head and neck tumor reconstruction, including free flaps such as the radial forearm, anterolateral thigh, scapular tip, and myocutaneous flaps, among others. The success rates for free flap reconstructions ranged from 85% to 100%, with notable variations attributed to patient selection, tumor characteristics, and surgical expertise. Conclusions: Complications such as flap necrosis, infection, hematoma, and donor site morbidity were documented across studies, highlighting the importance of meticulous surgical planning and postoperative care. Furthermore, the review revealed emerging techniques such as computer-aided design, virtual surgery, stereolithographic models, customized implants, tissue engineering, and allotransplants, offering promising reconstructive armamentarium. Advances in surgical techniques and emerging technologies hold promise for further enhancing reconstructive outcomes, minimizing morbidity, and improving patient quality of life.

Enhancing Surgical Vision: Augmented Reality in Otolaryngology-Head and Neck Surgery

Augmented reality (AR) technology has become widely established in otolaryngology-head and neck surgery. Over the past 20 years, numerous AR systems have been investigated and validated across the subspecialties, both in cadaveric and in live surgical studies. AR displays projected through head-mounted devices, microscopes, and endoscopes, most commonly, have demonstrated utility in preoperative planning, intraoperative guidance, and improvement of surgical decision-making. Specifically, they have demonstrated feasibility in guiding tumor margin resections, identifying critical structures intraoperatively, and displaying patient-specific virtual models derived from preoperative imaging, with millimetric accuracy. This review summarizes both established and emerging AR technologies, detailing how their systems work, what features they offer, and their clinical impact across otolaryngology subspecialties. As AR technology continues to advance, its integration holds promise for enhancing surgical precision, simulation training, and ultimately, improving patient outcomes.

Development of an augmented reality guidance system for head and neck cancer resection

The use of head-mounted augmented reality (AR) for surgeries has grown rapidly in recent years. AR aids in intraoperative surgical navigation through overlaying three-dimensional (3D) holographic reconstructions of medical data. However, performing AR surgeries on complex areas such as the head and neck region poses challenges in terms of accuracy and speed. This study explores the feasibility of an AR guidance system for resections of positive tumour margins in a cadaveric specimen. The authors present an intraoperative solution that enables surgeons to upload and visualize holographic reconstructions of resected cadaver tissues. The solution involves using a 3D scanner to capture detailed scans of the resected tissue, which are subsequently uploaded into our software. The software converts the scans of resected tissues into specimen holograms that are viewable through a head-mounted AR display. By re-aligning these holograms with cadavers with gestures or voice commands, surgeons can navigate the head and neck tumour site. This workflow can run concurrently with frozen section analysis. On average, the authors achieve an uploading time of 2.98 min, visualization time of 1.05 min, and re-alignment time of 4.39 min, compared to the 20 to 30 min typical for frozen section analysis. The authors achieve a mean re-alignment error of 3.1 mm. The authors' software provides a foundation for new research and product development for using AR to navigate complex 3D anatomy in surgery.

Intraoperative three-dimensional scanning of head and neck surgical defects: Enhanced communication and documentation of harvested supplemental margins

BACKGROUND

We have demonstrated the effectiveness of 3D resection specimen scanning for communicating margin results. We now address the corresponding surgical defect by debuting 3D defect models, which allow for accurate annotations of harvested supplemental margins.

METHODS

Surgical defects were rendered into 3D models, which were annotated to document the precise location of harvested supplemental margins. 3D defect scans were also compared with routine 2D photography and were analyzed for quality, clarity, and the time required to complete the scan.

RESULTS

Forty defects were scanned from procedures including segmental mandibulectomy, maxillectomy, and laryngopharyngectomy. Average duration of defect scan was 6 min, 45 s. In six of ten 2D photographs, the surgeon was unable to precisely annotate the extent of at least one supplemental margin.

CONCLUSION

3D defect scanning offers advantages in that this technique enables documentation of the precise location and breadth of supplemental margins harvested to address margins at-risk.