Optimization of computer-assisted intraoperative guidance for complex oncological procedures

Mención Internacional en el título de doctorThe role of technology inside the operating room is constantly increasing, allowing surgical procedures previously considered impossible or too risky due to their complexity or limited access. These reliable tools have improved surgical efficiency and safety. Cancer treatment is one of the surgical specialties that has benefited most from these techniques due to its high incidence and the accuracy required for tumor resections with conservative approaches and clear margins. However, in many cases, introducing these technologies into surgical scenarios is expensive and entails complex setups that are obtrusive, invasive, and increase the operative time. In this thesis, we proposed convenient, accessible, reliable, and non-invasive solutions for two highly complex regions for tumor resection surgeries: pelvis and head and neck. We explored how the introduction of 3D printing, surgical navigation, and augmented reality in these scenarios provided high intraoperative precision. First, we presented a less invasive setup for osteotomy guidance in pelvic tumor resections based on small patient-specific instruments (PSIs) fabricated with a desktop 3D printer at a low cost. We evaluated their accuracy in a cadaveric study, following a realistic workflow, and obtained similar results to previous studies with more invasive setups. We also identified the ilium as the region more prone to errors. Then, we proposed surgical navigation using these small PSIs for image-to-patient registration. Artificial landmarks included in the PSIs substitute the anatomical landmarks and the bone surface commonly used for this step, which require additional bone exposure and is, therefore, more invasive. We also presented an alternative and more convenient installation of the dynamic reference frame used to track the patient movements in surgical navigation. The reference frame is inserted in a socket included in the PSIs and can be attached and detached without losing precision and simplifying the installation. We validated the setup in a cadaveric study, evaluating the accuracy and finding the optimal PSI configuration in the three most common scenarios for pelvic tumor resection. The results demonstrated high accuracy, where the main source of error was again incorrect placements of PSIs in regular and homogeneous regions such as the ilium. The main limitation of PSIs is the guidance error resulting from incorrect placements. To overcome this issue, we proposed augmented reality as a tool to guide PSI installation in the patient’s bone. We developed an application for smartphones and HoloLens 2 that displays the correct position intraoperatively. We measured the placement errors in a conventional and a realistic phantom, including a silicone layer to simulate tissue. The results demonstrated a significant reduction of errors with augmented reality compared to freehand placement, ensuring an installation of the PSI close to the target area. Finally, we proposed three setups for surgical navigation in palate tumor resections, using optical trackers and augmented reality. The tracking tools for the patient and surgical instruments were fabricated with low-cost desktop 3D printers and designed to provide less invasive setups compared to previous solutions. All setups presented similar results with high accuracy when tested in a 3D-printed patient-specific phantom. They were then validated in the real surgical case, and one of the solutions was applied for intraoperative guidance. Postoperative results demonstrated high navigation accuracy, obtaining optimal surgical outcomes. The proposed solution enabled a conservative surgical approach with a less invasive navigation setup. To conclude, in this thesis we have proposed new setups for intraoperative navigation in two complex surgical scenarios for tumor resection. We analyzed their navigation precision, defining the optimal configurations to ensure accuracy. With this, we have demonstrated that computer-assisted surgery techniques can be integrated into the surgical workflow with accessible and non-invasive setups. These results are a step further towards optimizing the procedures and continue improving surgical outcomes in complex surgical scenarios.Programa de Doctorado en Ciencia y Tecnología Biomédica por la Universidad Carlos III de MadridPresidente: Raúl San José Estépar.- Secretario: Alba González Álvarez.- Vocal: Simon Droui

Unveiling the prospects of point-of-care 3D printing of Polyetheretherketone (PEEK) patient-specific implants

Additive manufacturing (AM) or three-dimensional (3D) printing is rapidly gaining acceptance in the healthcare sector. With the availability of low-cost desktop 3D printers and inexpensive materials, in-hospital or point-of-care (POC) manufacturing has gained considerable attention in personalized medicine. Material extrusion-based [Fused Filament Fabrication (FFF)] 3D printing of low-temperature thermoplastic polymer is the most commonly used 3D printing technology in hospitals due to its ease of operability and availability of low-cost machines. However, this technology has been limited to the production of anatomical biomodels, surgical guides, and prosthetic aids and has not yet been adopted into the mainstream production of patient-specific or customized implants. Polyetheretherketone (PEEK), a high-performance thermoplastic polymer, has been used mainly in reconstructive surgeries as a reliable alternative to other alloplastic materials to fabricate customized implants. With advancements in AM systems, prospects for customized 3D printed surgical implants have emerged, increasing attention for POC manufacturing. A customized implant may be manufactured within few hours using 3D printing, allowing hospitals to become manufacturers. However, manufacturing customized implants in a hospital environment is challenging due to the number of actions necessary to design and fabricate the implants. The focus of this thesis relies on material extrusion-based 3D printing of PEEK patient-specific implants (PSIs). The ambitious challenge was to bridge the performance gap between 3D printing of PEEK PSIs for reconstructive surgery and the clinical applicability at the POC by taking advantage of recent developments in AM systems. The main reached milestones of this project include: (i) assessment of the fabrication feasibility of PEEK surgical implants using material extrusion-based 3D printing technology, (ii) incorporation of a digital clinical workflow for POC manufacturing, (iii) assessment of the clinical applicability of the POC manufactured patient-specific PEEK scaphoid prosthesis, (iv) visualization and quantification of the clinical reliability of the POC manufactured patient-specific PEEK cranial implants, and (v) assessment of the clinical performance of the POC manufactured porous patient-specific PEEK orbital implants. During this research work, under the first study, we could demonstrate the prospects of FFF 3D printing technology for POC PEEK implant manufacturing. It was established that FFF 3D printing of PEEK allows the construction of complex anatomical geometries which cannot be manufactured using other technologies. With a clinical digital workflow implementation at the POC, we could further illustrate a smoother integration and faster implant production (within two hours) potential for a complex-shaped, patented PEEK patient-specific scaphoid prosthesis. Our results revealed some key challenges during the FFF printing process, exploring the applicability of POC manufactured FFF 3D printed PEEK customized implants in craniofacial reconstructions. It was demonstrated that optimal heat distribution around the cranial implants and heat management during the printing process are essential parameters that affect crystallinity, and thus the quality of the FFF 3D printed PEEK cranial implants. At this stage of the investigation, it was observed that the root mean square (RMS) values for dimensional accuracy revealed higher deviations in large-sized cranial prostheses with “horizontal lines” characteristics. Further optimization of the 3D printer, a layer-by-layer increment in the airflow temperature was done, which improved the performance of the FFF PEEK printing process for large-sized cranial implants. We then evaluated the potential clinical reliability of the POC manufactured 3D printed PEEK PSIs for cranial reconstruction by quantitative assessment of geometric, morphological, and biomechanical characteristics. It was noticed that the 3D printed customized cranial implants had high dimensional accuracy and repeatability, displaying clinically acceptable morphologic similarity concerning fit and contours continuity. However, the tested cranial implants had variable peak load values with discrete fracture patterns from a biomechanical standpoint. The implants with the highest peak load had a strong bonding with uniform PEEK fusion and interlayer connectivity, while air gaps and infill fusion lines were observed in implants with the lowest strength. The results of this preclinical study were in line with the clinical applicability of cranial implants; however, the biomechanical attribute can be further improved. It was noticed that each patient-specific reconstructive implant required a different set of manufacturing parameters. This was ascertained by manufacturing a porous PEEK patient-specific orbital implant. We evaluated the FFF 3D printed PEEK orbital mesh customized implants with a metric considering the design variants, biomechanical, and morphological parameters. We then studied the performance of the implants as a function of varying thicknesses and porous design constructs through a finite element (FE) based computational model and a decision matrix based statistical approach. The maximum stress values achieved in our results predicted the high durability of the implants. In all the implant profile configurations, the maximum deformation values were under one-tenth of a millimeter (mm) domain. The circular patterned design variant implant revealed the best performance score. The study further demonstrated that compounding multi-design computational analysis with 3D printing can be beneficial for the optimal restoration of the orbital floor. In the framework of the current thesis, the potential clinical application of material extrusion-based 3D printing for PEEK customized implants at the POC was demonstrated. We implemented clinical experience and engineering principles to generate a technical roadmap from preoperative medical imaging datasets to virtual surgical planning, computer-aided design models of various reconstructive implant variants, to the fabrication of PEEK PSIs using FFF 3D printing technology. The integration of 3D printing PEEK implants at the POC entails numerous benefits, including a collaborative team approach, quicker turnaround time of customized implants, support in pre-surgical and intraoperative planning, improved patient outcomes, and decreased overall healthcare cost. We believe that FFF 3D printing of customized PEEK implants could become an integral part of the hospitals and holds potential for various reconstructive surgery applications

The HoloLens in Medicine: A systematic Review and Taxonomy

The HoloLens (Microsoft Corp., Redmond, WA), a head-worn, optically see-through augmented reality display, is the main player in the recent boost in medical augmented reality research. In medical settings, the HoloLens enables the physician to obtain immediate insight into patient information, directly overlaid with their view of the clinical scenario, the medical student to gain a better understanding of complex anatomies or procedures, and even the patient to execute therapeutic tasks with improved, immersive guidance. In this systematic review, we provide a comprehensive overview of the usage of the first-generation HoloLens within the medical domain, from its release in March 2016, until the year of 2021, were attention is shifting towards it's successor, the HoloLens 2. We identified 171 relevant publications through a systematic search of the PubMed and Scopus databases. We analyze these publications in regard to their intended use case, technical methodology for registration and tracking, data sources, visualization as well as validation and evaluation. We find that, although the feasibility of using the HoloLens in various medical scenarios has been shown, increased efforts in the areas of precision, reliability, usability, workflow and perception are necessary to establish AR in clinical practice.Comment: 35 pages, 11 figure

Three-Dimensional Printing: A Novel Technology for Use in Oral and Maxillofacial Operations

Three-dimensional (3D) printing is cited as “a novel, fascinating, future builder technology” in many papers and articles. Use of this technology in the field of medicine and especially oral and maxillofacial surgery is expanding. The type of manufacturing systems, materials, cost-effectiveness, and also bio-printing, with studies from around the world today, make this field a “hot-topic” in reconstructive and regenerative surgery. This chapter evaluates the latest updates and scientific uses of 3D printing

로봇을 이용한 자율적 하악골채취 골절단술의 기초방법 개발과 그 정확도 평가

학위논문 (박사)-- 서울대학교 대학원 : 치의학대학원 치의과학과, 2019. 2. 김성민.Objectives: An autonomous robot osteotomy system using direct coordinate determination was developed in our study. The registration accuracy was evaluated by measuring the fiducial localization error (FLE) and target registration error (TRE) and the accuracy of the designed osteotomy method along a preprogrammed plan was evaluated. Furthermore, the accuracy of the robotic osteotomy and a manual osteotomy was compared in regard to cut position, length, angle and depth. Methods: A light-weight-robot was used in this study, with an electric gripper. A direct coordinate determination method, using three points on the teeth, was developed for registration and determination of FLE and TRE, as measured on a mandible model. Sixteen landmarks on the mandible were prepared with holes and zirconia beads and the TRE was computed in ten repeated measurements using the robot. A direct coordinate determination via three points was used for registering and a twenty stone model (7 cm x 7 cm x 3 cm). The osteotomy line was designed similar to the ramal bone graft (2 cm x 1 cm x 0.5 cm). To evaluate accuracy, we measured a position (how accurate the robot arm is located), length (how accurate the robot arm is moving while cutting), angle (the angle at which the robot arm is located), and depth (the depth of the disc cutting) error. Sixteen mandible phantoms were used to simulate the osteotomy for the ramus bone graft. An image of the phantom was obtained by three-dimensional camera scanning and a virtual ramal bone graft was designed with computer software. To evaluate an accuracy and precision, the mandible phantoms were scanned with cone beam computer tomography (CBCT). Cut position, length, angle and depth errors were measured and the results of the robotic surgery were compared with that of manual surgery. Results: The mean value of the FLE was 0.84 ± 0.38 mm and the third reference point which detected the lingual fossa of the right second molar had a larger error than the other reference points. The mean value of the TRE was 1.69 ± 0.82 mm and there were significant differences between the anterior body, posterior body, and coronoid/condyle groups. Landmarks at the anterior body had the lowest TRE (0.96 ± 0.47 mm) and landmarks on the coronoid and condyle had the highest TRE (2.12 ± 0.99 mm). An autonomous robot osteotomy with a direct coordinate determination using three points was successfully achieved. On the model RBG osteotomy, the posterior cut had 0.77±0.32 absolute mean value, the anterior cut had 0.82±0.43, the inferior cut had 0.76 ± 0.38 and the superior cut had 1.37 ± 0.83, respectively. The absolute mean values for osteotomy errors for position, length, angle, and depth were 0.93 ± 0.45 mm, 0.81 ± 0.34 mm, 1.26 ± 1.35°, and 1.19 ± 0.73 mm, respectively. The position and length errors were significantly lower than angle and depth errors. In the comparison between robotic surgery and manual surgery, there were significant differences of absolute mean value and variance in all categories. For the robotic surgery, the cut position, length, angle and depth errors were 0.70 ± 0.34 mm, 0.35 ± 0.19 mm, 1.32 ± 0.96° and 0.59 ± 0.46 mm, respectively. For the manual surgery, the cut position, length, angle and depth errors were 1.83 ± 0.65 mm, 0.62 ± 0.37 mm, 5.96 ± 3.47° and 0.40 ± 0.31 mm, respectively. The robotic surgery had significantly higher accuracy and lower variance for cut position, length and angle errors. On the other hand, the depth error had a significantly higher absolute mean value and variance than the robotic surgery. Conclusions: An autonomous robot osteotomy scheme was developed, using the direct coordinate determination by three points on the teeth, and proved an accurate method for registration. The incisal edge or buccal pit of the teeth were more proper reference points than the fossa of the teeth. The measured RMS of the TRE increased when the target moved away from the reference points. Robotic surgery showed high accuracy and precision in positioning and reduced accuracy in controlling the depth of disc sawing. The robotic surgery showed high accuracy and precision in positioning and somewhat low accuracy in controlling the depth of the disc sawing. Comparing robotic and manual surgeries, the robotic surgery was superior in accuracy and precision in position, length and angle. However, the manual surgery had higher accuracy and precision in depth.1. 목 적 본 연구에서는 세 점 접촉을 통한 좌표 결정 방식을 통해 실제 모델의 좌표와 로봇이 가지고 있는 좌표를 정합하는 방식을 이용하여 자율 로봇을 이용한 하악골채취 골절단술의 기초방법을 개발하고자 한다. 개발된 정합 방법의 위치 추적 오류 (fiducial localization error)와 목표 정합 오류 (target registration error)를 측정하여 정합의 정확성을 평가하고자 한다. 또한 사전에 프로그래밍된 골절단을 직육면체 모델에 시행하고 위치, 길이, 각도, 깊이의 오류를 측정하여 정확성을 알아보고자 한다. 추가적으로 3차원 가상수술을 통해 하악 상행지 골이식술(ramal bone graft)을 설계하고 하악 팬텀 모형에서 이에 맞게 자율 로봇이 골절단술을 수행하여 악골에서 있어서 로봇을 이용한 골절단술의 정확성을 평가해 보고 반대측은 대조군으로 외과의가 기존의 전통적인 방식으로 골절단술을 수행함으로써 양측을 비교하고자 한다. 2. 방 법 본 연구에서는 경량 로봇의 최종 작용체(end effector)에 전자 그리퍼(gripper)를 연결하고 이 그리퍼가 수술용 절삭기구나 디스크가 연결된 치과용 핸드피스를 잡고 골절단을 수행하도록 하였다. 실제 모델의 좌표와 로봇이 가지고 있는 좌표를 중첩하기 위해 세 점을 찍어 첫번째 점을 원점으로 하고, 두번째 점의 방향을 x축으로, 그리고 세 번째 점이 결정하는 평면을 xy 평면으로 인식하도록 하였다. 첫번째 실험에서는 위치 추적 오류와 목표 정합 오류의 평가를 위해 하악골 모델에 치아의 기준 세 점과 하악골의 총 16개의 목표 위치에 1mm 구멍을 뚫고 1mm 지름의 지르코니아 구를 적용하여 CBCT 상에서 잘 보일 수 있도록 하였다. 각 목표 위치에 10번씩 반복하여 위치를 인식하여 오류를 계산하고 목표 정합 오류의 위치별 차이를 분석하였다. 두번째 실험에서는 총 20 개의 직육면체 석고 모델 (7cm x 7cm x 3cm)을 제작하였고 석고의 절단 크기는 하악 상행지 골채취을 위한 골절단 크기 (2cm x 1cm x 0.5cm)와 동일하게 설계하였다. 로봇팔을 이용하여 3점 접촉을 하면 좌표값을 계산하여 미리 프로그래밍된 위치에서 골절단을 수행하였다. 로봇에 의해 수행된 석고 절단선은 위치, 길이 각도 및 깊이로 나누어 오류를 측정하였다. 세번째 실험에서는 하악 상행지 골채취를 위한 골절단 실험을 위해 총 16개의 하악 팬텀 모형을 사용하였다. 팬텀 모형을 삼차원 스캐닝으로 삼차원 영상을 얻고 가상 수술을 시행하여 골절단 크기와 형태 그리고 그 위치에 대한 계획을 세웠다. 이 가상 수술 계획에 따라 로봇이 팬텀 모델에 골절단 수술을 하였다. 반대 측은 대조군으로 기존의 전통적인 방식으로 외과의가 수행하여 양측의 오차를 비교하였다. 절단선의 위치, 길이, 각도 및 깊이를 측정하여 각각의 정확도를 비교하였다. 위치 오류는 x축으로는 로봇이 표면 접촉을 인식하고 골절단을 시행하기에 0의 값으로 측정되었고 y 축과 z 축으로 나누어 측정되었으며 평균값과 제곱평균제곱근를 계산하였다. 3. 결 과 위치 추적 오류와 목표 정합 오류는 각각 0.49±0.22 mm 와 0.98±0.47 mm로 측정되었으며 기준접에서 멀어질수록 목표 정합 오류는 더 큰 값을 보였다. 석고 모델 실험에서 절단선의 위치, 길이, 각도 및 깊이의 평균과 표준오차는 각각 0.93 ± 0.45 mm, 0.81 ± 0.34 mm, 1.26 ± 1.35°, 1.19 ± 0.73 mm 이었다. 위치가 가장 정확한 값을 보였으며 길이 그리고 깊이 순으로 오차가 증가하였으며, 각도와 절단 깊이 제어가 가장 오차가 많은 술식이었다. 하악 팬텀 수술에서 로봇을 이용한 골절단의 위치, 길이, 각도 및 깊이 오차 값은 각각 0.70 ± 0.34 mm, 0.35 ± 0.19 mm, 1.32 ± 0.96°, 0.59 ± 0.46 mm 였으며 외과의의 골절단에서는 값이 각각 1.83 ± 0.65 mm, 0.62 ± 0.37 mm, 5.96 ± 3.47°, 0.40 ± 0.31 mm 였다. 위치, 길이, 각도 오차는 로봇이 더 작은 값을 보였고 깊이 오차는 외과의의 수술에서 더 작은 값을 보였다. 4. 결 론 본 연구에서는 하악 상행지 골채취를 위한 자율 로봇을 이용한 골절단 시스템을 개발하였고 위치추적오류와 목표정합오류 모두 우수한 값을 보였다. 석고 모형과 하악 팬텀 모향을 이용한 두가지 실험 모두에서 유용성과 향상된 정확성을 확인할 수 있었다. 세점 접촉 좌표 결정 시스템은 실제 모델의 좌표를 로봇의 좌표로 등록하는 데 유용한 시스템이었으며, 하악 상행지 골절단술에 대한 자율로봇 시스템의 정확도는 기존의 외과의가 직접 수행하는 방식보다 우수하였다.Abstract (in English) 1. Introduction 1 2. Materials and Methods. 12 3. Results 26 4. Discussion 32 5. Conclusions 40 6. References 41 Tables and Figures 48 Abstract (in Korean) 74Docto

Anatomical and functional custom made restoration techniques with Direct Metal Laser Forming technology: systematic workflow and CAD-CAM

Introduction Bone defects are usually repaired by the body’s healing process itself. If severe fracture, tumor or infection occur on large bones, it poses a serious challenge to the regeneration ability of the bones. One of the latest advancement in medical science is the rapid prototyping technologies. Therefore, the aim of the present study was the developing and testing of a reliable workflow to fabricate custom-made grafts in the field craniofacial surgery. Material and Methods In this study 14 patients with different cranio-facial bone defects were enrolled. Two evaluation methods were associated to test the results of the workflow. Surveys were given to patients undergone surgery and their surgeons to have a subjective analysis of the workflow. For each patient the produced prosthesis was superimposed on the original prosthesis design, the displacement between was evaluated. Results Significant level of discomfort at 4 weeks after surgery compared to 2 days after surgery, aesthetic improvement significant improved 1 year after surgery compared to 4 weeks after surgery. Aesthetic improvement 1 year after surgery and aesthetic improvement according to expectations showed correlation, aesthetic improvement 1 year after surgery and aesthetic improvement according to expectations showed correlation. The mean distance of the printed model was significant smaller than the virtual model, with a mean difference of -0.075 mm. Conclusion According to the results of the present study custom made bone graft made with laser sintering technique represents a valid alternative to traditional bone grafts with high clinical accuracy and the advantage to avoid morbidity of the donor site or of the patient due to animal grafting

The value of medical 3D printing : hope versus hype

3D printing has been growing fast in the medical field. While preliminary clinical results have been reported in the literature, it’s health economic value has not been analyzed yet. Medical 3D printing has found its main applications in surgery; especially orthopedics and reconstructive surgery. Its applications rage from anatomic models to surgical guides and implants. All of these can be seen as consecutive levels of integration. While papers often report improved clinical results, a great accuracy and an acceptable price, few of these are backed with numbers. We performed 3 health economic analyses using Markov models using a payer perspective on each of these 3 levels of integration. As a first level, we analyzed the impact of using anatomic models as a tool for surgical planning in congenital heart diseases for 9 different procedures. Results varied from not being cost effective for atrial septum defects, to being highly cost-effective in highly complex procedures such as a Norwood repair. Second, we analyzed the already well integrated use of surgical guides for primary total knee arthroplasty using Belgian registry data. The database approach showed an significantly reduced revision rate in the group using custom guides compared to the conventional approach. The Markov models showed the technology to be cost-effective if CT-based guides are used. At last, we analyzed the use of custom 3D printed acetabular implants for revision surgery in patients with acetabular defects compared to non-3D printed custom implants. The 3D printed implants showed to be cost effective, especially in younger patients. The final chapter gives an overview of the pitfalls encountered during these preliminary analyses and gives a glance at possible solutions to allow better analysis and faster adoption of medical innovations

A Cone Beam Computed Tomography Annotation Tool for Automatic Detection of the Inferior Alveolar Nerve Canal

In recent years, deep learning has been employed in several medical fields, achieving impressive results. Unfortunately, these algorithms require a huge amount of annotated data to ensure the correct learning process. When dealing with medical imaging, collecting and annotating data can be cumbersome and expensive. This is mainly related to the nature of data, often three-dimensional, and to the need for well-trained expert technicians. In maxillofacial imagery, recent works have been focused on the detection of the Inferior Alveolar Nerve (IAN), since its position is of great relevance for avoiding severe injuries during surgery operations such as third molar extraction or implant installation. In this work, we introduce a novel tool for analyzing and labeling the alveolar nerve from Cone Beam Computed Tomography (CBCT) 3D volumes

Personalized Surgery Service in a Tertiary Hospital: A Method to Increase Effectiveness, Precision, Safety and Quality in Maxillofacial Surgery Using Custom-Made 3D Prostheses and Implants

Personalized surgery; Tertiary hospital; Virtual planningCirugía personalizada; Hospital terciario; Planificación virtualCirurgia personalitzada; Hospital terciari; Planificació virtualPersonalized surgery (PS) involves virtual planning (VP) and the use of 3D printing technology to design and manufacture custom-made elements to be used during surgery. The widespread use of PS has fostered a paradigm shift in the surgical process. A recent analysis performed in our hospital—along with several studies published in the literature—showed that the extensive use of PS does not preclude the lack of standardization in the process. This means that despite the widely accepted use of this technology, standard individual roles and responsibilities have not been properly defined, and this could hinder the logistics and cost savings in the PS process. The aim of our study was to describe the method followed and the outcomes obtained for the creation of a PS service for the Oral and Maxillofacial Surgery Unit that resolves the current absence of internal structure, allows for the integration of all professionals involved and improves the efficiency and quality of the PS process. We performed a literature search on the implementation of PS techniques in tertiary hospitals and observed a lack of studies on the creation of PS units or services in such hospitals. Therefore, we believe that our work is innovative and has the potential to contribute to the implementation of PS units in other hospitals

Validazione di un dispositivo indossabile basato sulla realta aumentata per il riposizionamento del mascellare superiore

Aim: We present a newly designed, localiser-free, head-mounted system featuring augmented reality (AR) as an aid to maxillofacial bone surgery, and assess the potential utility of the device by conducting a feasibility study and validation. Also, we implement a novel and ergonomic strategy designed to present AR information to the operating surgeon (hPnP). Methods: The head-mounted wearable system was developed as a stand- alone, video-based, see-through device in which the visual features were adapted to facilitate maxillofacial bone surgery. The system is designed to exhibit virtual planning overlaying the details of a real patient. We implemented a method allowing performance of waferless, AR-assisted maxillary repositioning. In vitro testing was conducted on a physical replica of a human skull. Surgical accuracy was measured. The outcomes were compared with those expected to be achievable in a three-dimensional environment. Data were derived using three levels of surgical planning, of increasing complexity, and for nine different operators with varying levels of surgical skill. Results: The mean linear error was 1.70±0.51mm. The axial errors were 0.89±0.54mm on the sagittal axis, 0.60±0.20mm on the frontal axis, and 1.06±0.40mm on the craniocaudal axis. Mean angular errors were also computed. Pitch: 3.13°±1.89°; Roll: 1.99°±0.95°; Yaw: 3.25°±2.26°. No significant difference in terms of error was noticed among operators, despite variations in surgical experience. Feedback from surgeons was acceptable; all tests were completed within 15 min and the tool was considered to be both comfortable and usable in practice. Conclusion: Our device appears to be accurate when used to assist in waferless maxillary repositioning. Our results suggest that the method can potentially be extended for use with many surgical procedures on the facial skeleton. Further, it would be appropriate to proceed to in vivo testing to assess surgical accuracy under real clinical conditions.Obiettivo: Presentare un nuovo sistema indossabile, privo di sistema di tracciamento esterno, che utilizzi la realtà aumentata come ausilio alla chirurgia ossea maxillo-facciale. Abbiamo validato il dispositivo. Inoltre, abbiamo implementato un nuovo metodo per presentare le informazioni aumentate al chirurgo (hPnP). Metodi: Le caratteristiche di visualizzazione del sistema, basato sul paradigma video see-through, sono state sviluppate specificamente per la chirurgia ossea maxillo-facciale. Il dispositivo è progettato per mostrare la pianificazione virtuale della chirurgia sovrapponendola all’anatomia del paziente. Abbiamo implementato un metodo che consente una tecnica senza splint, basata sulla realtà aumentata, per il riposizionamento del mascellare superiore. Il test in vitro è stato condotto su una replica di un cranio umano. La precisione chirurgica è stata misurata confrontando i risultati reali con quelli attesi. Il test è stato condotto utilizzando tre pianificazioni chirurgiche di crescente complessità, per nove operatori con diversi livelli di abilità chirurgica. Risultati: L'errore lineare medio è stato di 1,70±0,51mm. Gli errori assiali erano: 0,89±0,54mm sull'asse sagittale, 0,60±0,20mm sull'asse frontale, e 1,06±0,40mm sull'asse craniocaudale. Anche gli errori angolari medi sono stati calcolati. Beccheggio: 3.13°±1,89°; Rollio: 1,99°±0,95°; Imbardata: 3.25°±2,26°. Nessuna differenza significativa in termini di errore è stata rilevata tra gli operatori. Il feedback dei chirurghi è stato soddisfacente; tutti i test sono stati completati entro 15 minuti e lo strumento è stato considerato comodo e utilizzabile nella pratica. Conclusione: Il nostro dispositivo sembra essersi dimostrato preciso se utilizzato per eseguire il riposizionamento del mascellare superiore senza splint. I nostri risultati suggeriscono che il metodo può potenzialmente essere esteso ad altre procedure chirurgiche sullo scheletro facciale. Inoltre, appare utile procedere ai test in vivo per valutare la precisione chirurgica in condizioni cliniche reali