Pouzdanost kompjuterizovanih kefalometrijskih predviđanja rezultata hirurške korekcije mandibularnog prognatizma

Introduction. A successful treatment outcome in dentofacial deformity patients commonly requires combined orthodontic-surgical therapy. This enables us to overcome functional, aesthetic and psychological problems. Since most patients state aesthetics as the primary motive for seeking therapy, cephalometric predictions of treatment outcome have become the essential part of treatment planning, especially in combined orthodontic-surgical cases. Objective. The aim of this study was to evaluate the validity and reliability of computerized orthognathic surgery outcome predictions generated using the Nemotec Dental Studio NX 2005 software. Methods. The sample of the study consisted of 31 patients diagnosed with mandibular prognathism who were surgically treated at the Hospital for Maxillofacial Surgery in Belgrade. Investigation was done on lateral cephalograms made before and after surgical treatment. Cephalograms were digitized and analyzed using computer software. According to measurements made on superimposed pre- and postsurgical cephalograms, the patients were retreated within the software and the predictions were assessed by measuring seven angular and three linear parameters. Prediction measurements were then compared with the actual outcome. Results. Results showed statistically significant changes between posttreatment and predicted values for parameters referring to lower lip and mentolabial sulcus position. Conclusion. Computerized cephalometric predictions for hard-tissue structures in the sagittal and vertical planes, as well as the VTO parameters, generated using the Nemotec Dental Studio NX 2005 software are reliable, while lower lip and mentolabial sulcus position predictions are not reliable enough.Uvod. Radi postizanja što boljih krajnjih rezultata, osobe sa dentofacijalnim deformitetima najčešće se leče kombinovanom ortodontsko-hirurškom terapijom. Na taj način rešavaju se funkcionalni, estetski i psihološki problemi. Kako najveći broj pacijenata navodi estetsku promenu kao primarni motiv lečenja, kefalometrijsko predviđanje ishoda je važan deo planiranja terapije, posebno kod složenih slučajeva. Cilj rada. Cilj rada je bio da se proceni preciznost i pouzdanost predviđanja ishoda hirurške korekcije mandibularnog prognatizma razvijenih u okviru kompjuterskog softvera Nemotec Dental Studio NX 2005. Metode rada. Ispitan je 31 pacijent s mandibularnim prognatizmom koji je operisan na Klinici za maksilofacijalnu hirurgiju Stomatološkog fakulteta Univerziteta u Beogradu. Istraživanje je izvedeno na profilnim teleradiogramima snimljenim pre i posle hirurške intervencije. Nakon digitalizacije snimaka izvršena je kompjuterizovana kefalometrijska analiza. Na osnovu merenja određenih horizontalnih i vertikalnih rastojanja na preoperacionim i postoperacionim radiogramima, urađena je simulacija hirurških korekcija i na njima izmerena vrednost sedam angularnih parametara i tri linearna parametra, čija je vrednost upoređena s vrednostima na postoperacionim radiogramima. Rezultati. Ustanovljene su statistički značajne razlike između postoperacionih i predviđenih vrednosti za parametre koji govore o položaju donje usne i mentolabijalnog sulkusa. Zaključak. Kompjuterizovana kefalometrijska predviđanja položaja čvrstotkivnih struktura u sagitalnoj i vertikalnoj ravni, kao i VTO parametara, dobijena u okviru korišćenog programa su pouzdana, dok su predviđanja položaja donje usne i mentolabijalnog sulkusa nedovoljno pouzdana

From bench to bedside - current clinical and translational challenges in fibula free flap reconstruction.

Fibula free flaps (FFF) represent a working horse for different reconstructive scenarios in facial surgery. While FFF were initially established for mandible reconstruction, advancements in planning for microsurgical techniques have paved the way toward a broader spectrum of indications, including maxillary defects. Essential factors to improve patient outcomes following FFF include minimal donor site morbidity, adequate bone length, and dual blood supply. Yet, persisting clinical and translational challenges hamper the effectiveness of FFF. In the preoperative phase, virtual surgical planning and artificial intelligence tools carry untapped potential, while the intraoperative role of individualized surgical templates and bioprinted prostheses remains to be summarized. Further, the integration of novel flap monitoring technologies into postoperative patient management has been subject to translational and clinical research efforts. Overall, there is a paucity of studies condensing the body of knowledge on emerging technologies and techniques in FFF surgery. Herein, we aim to review current challenges and solution possibilities in FFF. This line of research may serve as a pocket guide on cutting-edge developments and facilitate future targeted research in FFF

A pilot study for the digital replacement of a distorted dentition acquired by Cone Beam Computed Tomography (CBCT)

Abstract Introduction: Cone beam CT (CBCT) is becoming a routine imaging modality designed for the maxillofacial region. Imaging patients with intra-oral metallic objects cause streak artefacts. Artefacts impair any virtual model by obliterating the teeth. This is a major obstacle for occlusal registration and the fabrication of orthognathic wafers to guide the surgical correction of dentofacial deformities. Aims and Objectives: To develop a method of replacing the inaccurate CBCT images of the dentition with an accurate representation and test the feasibility of the technique in the clinical environment. Materials and Method: Impressions of the teeth are acquired and acrylic baseplates constructed on dental casts incorporating radiopaque registration markers. The appliances are fitted and a preoperative CBCT is performed. Impressions are taken of the dentition with the devices in situ and subsequent dental models produced. The models are scanned to produce a virtual model. Both images of the patient and the model are imported into a virtual reality software program and aligned on the virtual markers. This allows the alignment of the dentition without relying on the teeth for superimposition. The occlusal surfaces of the dentition can be replaced with the occlusal image of the model. Results: The absolute mean distance of the mesh between the markers in the skulls was in the region of 0.09mm ± 0.03mm; the replacement dentition had an absolute mean distance of about 0.24mm ± 0.09mm. In patients the absolute mean distance between markers increased to 0.14mm ± 0.03mm. It was not possible to establish the discrepancies in the patient’s dentition, since the original image of the dentition is inherently inaccurate. Conclusion: It is possible to replace the CBCT virtual dentition of cadaveric skulls with an accurate representation to create a composite skull. The feasibility study was successful in the clinical arena. This could be a significant advancement in the accuracy of surgical prediction planning, with the ultimate goal of fabrication of a physical orthognathic wafer using reverse engineering

Dental health care technologies: factors affecting technology adoption and latest information technology solutions

The thesis studies the factors affecting information technology adoption in dental health care. The scope is on information systems used in diagnostics and clinical work. Besides the factors affecting technology adoption, the possibilities and challenges of two important technologies, 3D virtual workflow and CAD/CAM are introduced. The 3D technologies are studied further through a case study, Planmeca Romexis 3D applications. Through the thesis, the effects of the technologies for the whole value chain from the technology vendor to the patient are evaluated. Also, the economical side of the technologies is discussed. The thesis is based on a broad literature review. At first, dental clinical workflow is introduced to understand what kind of environment the information systems are facing. Second, a theoretical framework for technology adoption including Technology Acceptance Model by Davis (1989) and related theories is constructed, followed by a more throughout literature review on the factors characteristic to clinical environment and dental health care. The literature review is supported with the case study and interviews of specialists. The literature review finds various factors for technology adoption in dental health care. These factors are divided into usability and functional factors, work efficiency factors, learning curve factors and social & organisational factors. The general theoretical framework can be seen rather applicable for dental health care scope, but some factors such as patient safety or dental team’s sociocultural relationships are very characteristic to dentistry. 3D virtual workflow and CAD/CAM are seen to provide advantages into dentistry, and they’re bringing solutions to the factors discussed in the thesis. The thesis founds also challenges and problems arising from these technologies. Planmeca’s solutions are providing further insight on the possibilities of real-life solutions for 3D virtual workflow. The thesis has limitations since it’s based on a literature review, but a similar Information System Management-view for information systems in dentistry is rather rare. Thus, it can provide information on which factors to take into consideration for vendors designing dental information systems as well as for organizations that are considering investing in new information systems

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

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

From bench to bedside – current clinical and translational challenges in fibula free flap reconstruction

Fibula free flaps (FFF) represent a working horse for different reconstructive scenarios in facial surgery. While FFF were initially established for mandible reconstruction, advancements in planning for microsurgical techniques have paved the way toward a broader spectrum of indications, including maxillary defects. Essential factors to improve patient outcomes following FFF include minimal donor site morbidity, adequate bone length, and dual blood supply. Yet, persisting clinical and translational challenges hamper the effectiveness of FFF. In the preoperative phase, virtual surgical planning and artificial intelligence tools carry untapped potential, while the intraoperative role of individualized surgical templates and bioprinted prostheses remains to be summarized. Further, the integration of novel flap monitoring technologies into postoperative patient management has been subject to translational and clinical research efforts. Overall, there is a paucity of studies condensing the body of knowledge on emerging technologies and techniques in FFF surgery. Herein, we aim to review current challenges and solution possibilities in FFF. This line of research may serve as a pocket guide on cutting-edge developments and facilitate future targeted research in FFF