Philipp Jürgens

A new soft-tissue simulation strategy for cranio-maxillofacial surgery using facial muscle template model

We propose a computationally efficient, bio-mechanically relevant soft-tissue simulation method for cranio-maxillofacial (CMF) surgery. Special emphasis is given to comply with the current clinical workflow. A template-based facial muscle prediction was introduced to avoid laborious segmentation from medical images. In addition, transversely isotropic mass-tensor model (MTM) was applied to realize the directional behavior of facial muscles in short computation time. Finally, sliding contact was incorporated to mimic realistic boundary condition in error-sensitive regions. Mechanical simulation result was compared with commercial finite element software. And retrospective validation study with post-operative scan of four CMF cases was performed.

Anatomically-driven soft-tissue simulation strategy for cranio-maxillofacial surgery using facial muscle template model

We propose a computationally efficient and bio-mechanically relevant soft-tissue simulation method for cranio-maxillofacial (CMF) surgery. A template-based facial muscle reconstruction was introduced to minimize the efforts on preparing a patient-specific model. A transversely isotropic mass-tensor model (MTM) was adopted to realize the effect of directional property of facial muscles in reasonable computation time. Additionally, sliding contact around teeth and mucosa was considered for more realistic simulation. Retrospective validation study with postoperative scan of a real patient showed that there were considerable improvements in simulation accuracy by incorporating template-based facial muscle anatomy and sliding contact.

Prediction of Cranio-Maxillofacial Surgical Planning Using an Inverse Soft Tissue Modelling Approach

In cranio-maxillofacial surgery, the determination of a proper surgical plan is an important step to attain a desired aesthetic facial profile and a complete denture closure. In the present paper, we propose an efficient modeling approach to predict the surgical planning on the basis of the desired facial appearance and optimal occlusion. To evaluate the proposed planning approach, the predicted osteotomy plan of six clinical cases that underwent CMF surgery were compared to the real clinical plan. Thereafter, simulated soft-tissue outcomes were compared using the predicted and real clinical plan. This preliminary retrospective comparison of both osteotomy planning and facial outlook shows a good agreement and thereby demonstrates the potential application of the proposed approach in cranio-maxillofacial surgical planning prediction.

Comparative microstructural analysis of bone osteotomies after cutting by computer-assisted robot-guided laser osteotome and piezoelectric osteotome: an in vivo animal study

Most industrial laser applications utilize computer and robot assistance, for guidance, safety, repeatability, and precision. In contrast, medical applications using laser systems are mostly conducted manually. The advantages can be effective only when the system is coupled to a robotic guidance, as operating by hand does not reach the required accuracy. We currently developed the first laser osteotome which offers preoperative planning based on CT data, robot guidance, and a precise execution of the laser cuts. In an animal trial, our system was used to create a grid pattern of the same depth on the inner layer of parietal bone in 12 adult sheep. The same bone cuts were done with piezoelectric osteotome on the contralateral side. The micro-CT and histological analysis showed more new mineralized bone in the laser group compared to the piezoelectric group. As well, a cutting pattern with especially a constant osteotomy depth in the laser group was demonstrated. The here presented autonomous osteotomy tool shows not only an advantage in early bone healing stage but additionally sharp bone cuts with a very high accuracy and freely selectable design cuts.

Accuracy improvement in Cranio-Maxillofacial soft tissue simulation using a muscle embedded meshing approach

In the presented paper, we propose to improve the state-of-the-art approach for Cranio-Maxillofacial (CMF) soft tissue simulation by considering a new image-based meshing approach that accurately models the interface between different tissue types. The proposed approach has been initially evaluated on soft tissue deformations of four patients undergoing CMF surgery using post-operative CT scans. The results indicate improved prediction and robustness of the surgical planning outcome when compared to the state-of-the-art method while decreasing the simulation time.

Landmark-Based Surgical Navigation

Navigational support is a widely adopted technique in surgery that has become a part of the clinical routine. This navigation support either comes in the form of an abstract display that shows for example the distance and direction to the target position or in the form of augmented reality where segmented anatomical structures of interest are overlaid onto a visual image sequence in real-time.

Surgery for obstructive sleep apnoea in adults

This is a protocol for a Cochrane Review (Intervention). The objectives are as follows: To review the benefits and harms of surgery for the treatment of obstructive sleep apnoea.

Advanced Design System for Infantile Cranium Shape Model Growth Prediction

We present a longitudinal statistical shape/volumetric model of the cranium of infants and use it as prior information to support the design of cranial shape correction helmets. In addition, a logical approach based on natural brain growth is considered to derive necessary formulation to calculate the required treatment duration. The respective morphological analysis and statistical model will be integrated into the current haptic-based design pipeline of a company to produce an effective computer-assisted design system.

Computational Image-Guided Technologies in Cranio-Maxillofacial Soft Tissue Planning and Simulation

Due to the complexity and unpredictability of cranio-maxillofacial (CMF) surgery, computer simulations have been proposed to assist the surgeon in the decision-making process of surgical planning. Current planning solutions require the use of different and unconnected tools to account for the necessary balance and interplay between functional and aesthetic aspects of CMF surgery, which ultimately makes an effective combination and analysis of the information difficult. In this article we present current approaches and new trends suggested to alleviate these issues and to promote the development of clinically relevant and seamless, yet effective, computational solutions for CMF surgical planning.

Ethik in der dentomaxillofazialen Bildgebung

ZusammenfassungEthik in der dentomaxillofazialen Radiologie ist sowohl für den Kliniker als auch für den niedergelassenen Mund-, Kiefer- und Gesichtschirurgen im Alltag relevant und sollte bewusst wahrgenommen werden. Daher werden in diesem Beitrag folgende ethische Fragestellungen in Bezug auf die dentomaxillofaziale Bildgebung diskutiert: Welche Schwierigkeiten treten in der praktischen Anwendung auf?Wie sind Ethik und Ökonomie vereinbar?Wie sind ethische Gesichtspunkte in Forschung und Lehre verankert?Wie soll man sich bei Minderjährigen/Schwangeren verhalten?Wann ist ein Ethikvotum erforderlich?Was sind häufige Rückfragen/Bedenken der Ethikkommission bei Forschungsvorhaben?Welches sind vorteilhafte Studiendesigns?Welche Veränderungen hat es in Bezug auf Publikationsanforderungen gegeben? Verschiedene Aspekte wie Gesetztestexte und Fallbeispiele werden hierzu verwendet.AbstractEthics in dentomaxillofacial radiology are an important aspect in the daily routine for clinicians as well as for oral and maxillofacial surgeons in private practice. Therefore, the following questions with respect to dentomaxillofacial radiology are raised and discussed in this article: Which difficulties occur in practical applications?How are ethics and economy compatible?How are the ethical aspects anchored in research and education?How should one behave with respect to minors and pregnant women?When is an ethical vote necessary?What are common inquiries and concerns of ethical committees with respect to research projects?Which study designs are advantageous?Which changes have occurred with respect to publication requirements? Various aspects, such as legislation and case scenarios are used for this purpose.