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This study is about estimating the reproducibility of finding palpation points of three different anatomical landmarks in the human body (Xiphoid Process and the 2 Hip Crests) to support a navigated ultrasound application. On 6 test subjects with different body mass index the three palpation points were located five times by two examiners. The deviation from the target position was calculated and correlated to the fat thickness above each palpation point. The reproducibility of the measurements had a mean error of ≈13.5 mm +- 4 mm, which seems to be sufficient for the desired application field.
With the progress of technology in modern hospitals, an intelligent perioperative situation recognition will gain more relevance due to its potential to substantially improve surgical workflows by providing situation knowledge in real-time. Such knowledge can be extracted from image data by machine learning techniques but poses a privacy threat to the staff’s and patients’ personal data. De-identification is a possible solution for removing visual sensitive information. In this work, we developed a YOLO v3 based prototype to detect sensitive areas in the image in real-time. These are then deidentified using common image obfuscation techniques. Our approach shows that it is principle suitable for de-identifying sensitive data in OR images and contributes to a privacyrespectful way of processing in the context of situation recognition in the OR.
Motivation
In order to enable context-aware behavior of surgical assistance systems, the acquisition of various information about the current intraoperative situation is crucial. To achieve this, the complex task of situation recognition can be delegated to a specialized system. Consequently, a standardized interface is required for the seamless transfer of the recognized contextual information to the assistance systems, enabling them to adapt accordingly.
Methods
Our group analyzed four medical interface standards to determine their suitability for exchanging intraoperative contextual information. The assessment was based on a harmonized data and service model derived from the requirements of expected context-aware use cases. The Digital Imaging and Communications in Medicine (DICOM) and IEEE 11073 for Service-oriented Device Connectivity (SDC) were identified as the most appropriate standards.
Results
We specified how DICOM Unified Procedure Steps (UPS), can be used to effectively communicate contextual information. We proposed the inclusion of attributes to formalize different granularity levels of the surgical workflow.
Conclusions
DICOM UPS SOP classes can be used for the exchange of intraoperative contextual information between a situation recognition system and surgical assistance systems. This can pave the way for vendor-independent context awareness in the OR, leading to targeted assistance of the surgical team and an improvement of the surgical workflow.
Uncontrolled movements of laparoscopic instruments can lead to inadvertent injury of adjacent structures. The risk becomes evident when the dissecting instrument is located outside the field of view of the laparoscopic camera. Technical solutions to ensure patient safety are appreciated. The present work evaluated the feasibility of an automated binary classification of laparoscopic image data using Convolutional Neural Networks (CNN) to determine whether the dissecting instrument is located within the laparoscopic image section. A unique record of images was generated from six laparoscopic cholecystectomies in a surgical training environment to configure and train The CNN. By using a temporary version of the neural network, the annotation of the training image files could be automated and accelerated. A combination of oversampling and selective data augmentation was used to enlarge the fully labelled image data set and prevent loss of accuracy due to imbalanced class volumes. Subsequently the same approach was applied to the comprehensive, fully annotated Cholec80 database. The described process led to the generation of extensive and balanced training image data sets. The performance of the CNN-based binary classifiers was evaluated on separate test records from both databases. On our recorded data, an accuracy of 0.88 with regard to the safety-relevant classification was achieved. The subsequent evaluation on the Cholec80 data set yielded an accuracy of 0.84. The presented results demonstrate the feasibility of a binary classification of laparoscopic image data for the detection of adverse events in a surgical training environment using a specifically configured CNN architecture.
Die Bereitstellung klinischer Informationen im Operationssaal ist ein wichtiger Aspekt zur Unterstützung des chirurgischen Teams. Die roboter-assistierte Ösophagusresektion ist ein besonders komplexer Eingriff, der Potenzial zur workflowbasierten Unterstützung bietet. Wir präsentieren erste Ergebnisse der Entwicklung eines Checklisten-Tools mit der zugrundeliegenden Modellierung des chirurgischen Workflows und Informationsbedarf der Chirurgen. Das Checklisten-Tool zeigt hierfür die durchzuführenden Schritte chronologisch an und stellt zusätzliche Informationen kontextadaptiert bereit. Eine automatische Dokumentation von Start- und Endzeiten einzelner OP-Phasen und Schritte soll zukünftige Prozessanalysen der Operation ermöglichen.
Model-guided Therapy and Surgical Workflow Systems are two interrelated research fields, which have been developed separately in the last years. To make full use of both technologies, it is necessary to integrate them and connect them to Hospital Information Systems. We propose a framework for integration of Model-guided Therapy in Hospital Information Systems based on the Electronic Medical Record, and a taskbased Workflow Management System, which is suitable for clinical end users. Two prototypes - one based on Business Process Modeling Language, one based on the serum-board - are presented. From the experience with these prototypes, we developed a novel personalized visualization system for Surgical Workflows and Model-guided Therapy. Key challenges for further development are automated situation detection and a common communication infrastructure.
Multi-dimensional patient data, such as time varying volume data, data of different imaging modalities, surface segmentations etc. are of growing importance in the clinical routine. For many use cases, it is of major importance to replicate a certain visualization of a data set created on one machine on a different computer using different software tools. Up until now, there exists no standardized methodology for this consistent presentation. We propose an extension of the Digital Imaging und Communications in Medicine (DICOM) called “Multi dimensional Presentation State” and outline scope and first results of the standardization process.
Motivation: Aim of this project is the automatic classification of total hip endoprosthesis (THEP) components in 2D Xray images. Revision surgeries of total hip arthroplasty (THA) are common procedures in orthopedics and trauma surgery. Currently, around 400.000 procedures per year are performed in the United States (US) alone. To achieve the best possible result, preoperative planning is crucial. Especially if parts of the current THEP system are to be retained.
Methods: First, a ground truth based on 76 X-ray images was created: We used an image processing pipeline consisting of a segmentation step performed by a convolutional neural network and a classification step performed by a support vector machine (SVM). In total, 11 classes (5 pans and 6 shafts) shall be classified.
Results: The ground truth generated was of good quality even though the initial segmentation was performed by technicians. The best segmentation results were achieved using a U-net architecture. For classification, SVM architectures performed much better than additional neural networks.
Conclusions: The overall image processing pipeline performed well, but the ground truth needs to be extended to include a broader variability of implant types and more examples per training class.
Clinical reading centers provide expertise for consistent, centralized analysis of medical data gathered in a distributed context. Accordingly, appropriate software solutions are required for the involved communication and data management processes. In this work, an analysis of general requirements and essential architectural and software design considerations for reading center information systems is provided. The identified patterns have been applied to the implementation of the reading center platform which is currently operated at the Center of Ophthalmology of the University Hospital of Tübingen.
Die DGCH registriert vermehrt Klagen aus der klinischen Praxis hinsichtlich der nicht vollständigen Vernetzung bzw. Integration von Gerätesystemen im Chirurgischen OP. Die Anzahl, der Funktionsumfang und der Komplexitätsgrad der verwendeten Geräte nehmen ständig zu und machen die Bedienung immer aufwendiger und damit schwieriger und fehleranfälliger, sodass eine Verbesserung bei der Unterstützung im Ablauf wünschenswert ist. Die Sektion Computer- und telematikassistierte Chirurgie (CTAC) der DGCH hat es auf Veranlassung des Generalsekretärs deshalb übernommen, eine aktuelle Bestandsaufnahme vorzunehmen und mögliche Ansätze zur Verbesserung des derzeitigen Status zu bewerten.
An operating room is a stressful work environment. Nevertheless, all involved persons have to work safely as there is no space for mistakes. To ensure a high level of concentration and seamless interaction, all involved persons have to know their own tasks and the tasks of their colleagues. The entire team must work synchronously at all times. To optimize the overall workflow, a task manager supporting the team was developed. In parallel, a common conceptual design of a business process visualization was developed, which makes all relevant information accessible in real-time during a surgery. In this context an overview of all processes in the operating room was created and different concepts for the graphical representation of these user-dependent processes were developed. This paper describes the concept of the task manager as well as the general concept in the field of surgery.
Access to clinical information during interventions is an important aspect to support the surgeon and his team in the OR. The OR-Pad research project aims at displaying clinically relevant information close to the patient during surgery. With the OR-Pad system, the surgeon shall be able to access case-specific information, displayed on a sterile-packaged, portable display device. Therefore, information shall be prepared before surgery and also be available afterwards. The project follows an user-centered design process. Within the third iteration, the interaction concept was finalized, resulting in an application that can be used in two modes, mobile and intraoperative, to support the surgeon before/after and during surgery, respectively. By supporting the surgeon perioperatively, it is expected to improve the information situation in the OR and thereby the quality of surgical results. Based on this concept, the system architecture was designed in detail, using a client-server architecture. Components, communication interfaces, exchanged data, and intended standards for data exchange of the OR-Pad system including connecting systems were conceived. Expert interviews by using a clickable prototype were conducted to evaluate the concepts.
Die Segmentierung und das Tracking von minimal-invasiven robotergeführten Instrumenten ist ein wesentlicher Bestandteil für verschiedene computer assistierte Eingriffe. Allerdings treten in der minimal-invasiven Chirurgie, die das Anwendungsfeld für den hier beschriebenen Ansatz darstellt, häufig Schwierigkeiten durch Reflexionen, Schatten oder visuelle Verdeckungen durch Rauch und Organe auf und erschweren die Segmentierung und das Tracking der Instrumente.
Dieser Beitrag stellt einen Deep Learning Ansatz für ein markerloses Tracking von minimal-invasiven Instrumenten vor und wird sowohl auf simulierten als auch realen Daten getestet. Es wird ein simulierter als auch realer Datensatz mit Ground Truth Kennzeichnung für die binäre Segmentierung von Instrument und Hintergrund erstellt. Für den simulierten Datensatz werden Bilder aus einem simulierten Instrument und realem Hintergrund zusammengesetzt. Im Falle des realen Datensatzes spricht man von der Zusammensetzung der Bilder aus einem realen Instrument und Hintergrund. Insgesamt wird auf den simulierten Daten eine Pixelgenauigkeit von 94.70 Prozent und auf den realen Daten eine Pixelgenauigkeit von 87.30 Prozent erreicht.
Purpose
Context awareness in the operating room (OR) is important to realize targeted assistance to support actors during surgery. A situation recognition system (SRS) is used to interpret intraoperative events and derive an intraoperative situation from these. To achieve a modular system architecture, it is desirable to de-couple the SRS from other system components. This leads to the need of an interface between such an SRS and context-aware systems (CAS). This work aims to provide an open standardized interface to enable loose coupling of the SRS with varying CAS to allow vendor-independent device orchestrations.
Methods
A requirements analysis investigated limiting factors that currently prevent the integration of CAS in today's ORs. These elicited requirements enabled the selection of a suitable base architecture. We examined how to specify this architecture with the constraints of an interoperability standard. The resulting middleware was integrated into a prototypic SRS and our system for intraoperative support, the OR-Pad, as exemplary CAS for evaluating whether our solution can enable context-aware assistance during simulated orthopedical interventions.
Results
The emerging Service-oriented Device Connectivity (SDC) standard series was selected to specify and implement a middleware for providing the interpreted contextual information while the SRS and CAS are loosely coupled. The results were verified within a proof of concept study using the OR-Pad demonstration scenario. The fulfillment of the CAS’ requirements to act context-aware, conformity to the SDC standard series, and the effort for integrating the middleware in individual systems were evaluated. The semantically unambiguous encoding of contextual information depends on the further standardization process of the SDC nomenclature. The discussion of the validity of these results proved the applicability and transferability of the middleware.
Conclusion
The specified and implemented SDC-based middleware shows the feasibility of loose coupling an SRS with unknown CAS to realize context-aware assistance in the OR.
The focus of the developed maturity model was set on processes. The concept of the widespread CMM and its practices has been transferred to the perioperative domain and the concept of the new maturity model. Additional optimization goals and technological as well as networking-specific aspects enable a process- and object-focused view of the maturity model in order to ensure broad coverage of different subareas. The evaluation showed that the model is applicable to the perioperative field. Adjustments and extensions of the maturity model are future steps to improve the rating and classification of the new maturity model.
One of the key challenges for automatic assistance is the support of actors in the operating room depending on the status of the procedure. Therefore, context information collected in the operating room is used to gain knowledge about the current situation. In literature, solutions already exist for specific use cases, but it is doubtful to what extent these approaches can be transferred to other conditions. We conducted a comprehensive literature research on existing situation recognition systems for the intraoperative area, covering 274 articles and 95 cross-references published between 2010 and 2019. We contrasted and compared 58 identified approaches based on defined aspects such as used sensor data or application area. In addition, we discussed applicability and transferability. Most of the papers focus on video data for recognizing situations within laparoscopic and cataract surgeries. Not all of the approaches can be used online for real-time recognition. Using different methods, good results with recognition accuracies above 90% could be achieved. Overall, transferability is less addressed. The applicability of approaches to other circumstances seems to be possible to a limited extent. Future research should place a stronger focus on adaptability. The literature review shows differences within existing approaches for situation recognition and outlines research trends. Applicability and transferability to other conditions are less addressed in current work.
OR-Pad - Entwicklung eines Prototyps zur sterilen Informationsanzeige am OP-Situs : meeting abstract
(2019)
Hintergrund: Oftmals werden Informationen aus der Krankenakte oder von Bildgebungsverfahren nur auf recht weit vom Operationsgebiet entfernten Monitoren, außerhalb der ergonomischen Sichtachse des Operateurs, dargestellt. Dies führt dazu, dass relevante Informationen übersehen werden oder ihr Informationspotenzial nicht ausgeschöpft werden kann. In Papierform mitgenommene Notizen befinden sich während der OP außerhalb des sterilen Bereichs und sind dadurch für den Operateur nicht ohne Weiteres zugänglich. Auch bei intraoperativen Einträgen für die OP Dokumentation ist der Operateur auf die Mithilfe der Assistenz angewiesen. Durch die zusätzlichen Kommunikationswege entstehen dabei ein personeller und zeitlicher Mehraufwand und das Fehlerpotenzial nimmt zu. Das anwendungsorientierte Forschungsprojekt OR-Pad - Nutzung von portablen Informationsanzeigen im Operationssaal - soll dem Operateur zu einem verbesserten Informationsfluss verhelfen. Die Idee entstand aus der klinischen Routine der Anatomie und Urologie des Universitätsklinikums Tübingen und wird nun durch Fördermittel vom Ministerium für Wissenschaft, Forschung und Kunst Baden-Württemberg sowie vom Europäischen Fonds für regionale Entwicklung an der Hochschule Reutlingen zu einem High Fidelity-Prototypen weiterentwickelt.
Ziel: Ziel des OR-Pad Projekts ist es, während einer OP zum aktuellen Zeitpunkt klinisch relevante Informationen in unmittelbarer Nähe zum Operateur darzustellen. Mithilfe des Systems soll der Informationsfluss zwischen dem Eingriff sowie dessen Vor- und Nachbereitung optimiert werden. Der Operateur soll vorab relevante Informationen, wie aktuelle Röntgenbilder oder persönliche Notizen, zur intraoperativen Anzeige auswählen können, die dann am OP-Situs auf einer sterilen Informationsanzeige dargestellt werden. Durch die Positionierung soll eine ergonomische Sichtachse sowie die direkte Interaktion mit dem System ermöglicht werden. Kontextrelevante Informationen sollen basierend auf dem aktuellen OP-Verlauf durch die Entwicklung einer Situationserkennung automatisch bereitgestellt werden. Zur Optimierung des Informationsflusses gehört ebenfalls die Unterstützung der OP-Dokumentation. Für diese sollen während des Eingriffs manuell vom Operateur sowie automatisch vom System Einträge, wie Zeitpunkte oder intraoperative Aufnahmen, erstellt werden. Aus diesen soll nach dem Eingriff die OP-Dokumentation generiert und damit der Prozess qualitativer und zeiteffizienter gestaltet werden.
Methodik: Zur Erreichung des Ziels werden zunächst die klinischen Anforderungen spezifiziert und in ein Lastenheft überführt. Hierfür werden Interviews und Beobachtungen bei mehreren Interventionen durchgeführt. Nach dem User-Centered-Designprozess werden Personas und Nutzungsszenarien entworfen und mit klinischen Projektpartnern in mehreren Iterationen evaluiert. Es gilt eine Informationsarchitektur aufzubauen, die eine Einbettung klinischer Informationssysteme sowie Bild- und Gerätedaten aus dem OP-Netzwerk erlaubt. Eine Situationserkennung, basierend auf Prozessmodellen, soll zur Abschätzung des Operationsfortschritts entwickelt werden. Zur Befestigung der Informationsanzeige sollen geeignete Haltemechanismen eingesetzt werden. Das OR-Pad System soll laufend im Lehr- und Forschungs-OP der Hochschule Reutlingen getestet und im Sinne agiler Produktentwicklung mit den klinischen Projektpartnern abgestimmt werden. Der finale Funktionsprototyp soll abschließend in den Versuchs-OPs der Anatomie Tübingen getestet und evaluiert werden.
Ergebnisse: Über eine erste Datenerhebung mittels Contextual Inquiry konnten erste Anforderungen an das OR-Pad System erfasst werden, woraus ein Low-Fidelity-Prototyp resultierte. Die Evaluation über Experteninterviews führte in die zweite Iteration, in der das Konzept entsprechend der Ergebnisse angepasst wurde. Über Hospitationen am Uniklinikum Tübingen fand eine weitere Datenerhebung zur Erstellung von Szenarien für die intraoperativen Anwendungsfälle statt. Anhand der Anforderungen wurde ein Konzept für die Benutzerschnittstelle entworfen, die im weiteren Verlauf mit den klinischen Projektpartnern evaluiert wird.
Zur Unterstützung des Operateurs wird eine patientennahe Informationsanzeige entwickelt, die kontextrelevante Informationen entsprechend der aktuellen Situation bereitstellen kann. Hierfür soll eine Situationserkennung konzipiert werden, die auf unterschiedliche intraoperative Prozesse übertragen werden kann. Ziel der adaptiven Situationserkennung ist das Erkennen spezifischer Situationen durch intraoperative Informationen unterschiedlicher Datenquellen im Operationssaal. Innerhalb der Datenerhebung und -analyse wurden Anwendungsfälle für die Situationserkennung definiert sowie chirurgische Prozessmodelle erstellt, die intraoperative Ereignisse abbilden. Auf Basis dieser Informationen wurde ein Konzept entworfen, das sich zunächst auf die Erkennung abstrakter generalisierter Phasen, unabhängig vom Eingriff, fokussiert und sich Schritt für Schritt auf granulare Prozessschritte spezifizieren lässt. Diese Flexibilität soll die Übertragbarkeit des Konzepts auf intraoperative Prozesse ermöglichen und den Operateur dadurch gezielt mit kontextrelevanten Informationen unterstützen. Das Konzept wird in zukünftigen Schritten weiterentwickelt.
Context-aware systems to support actors in the operating room depending on the status of the intervention require knowledge about the current situation in the intra-operative area. In literature, solutions to achieve situation awareness already exist for specific use cases, but applicability and transferability to other conditions are less addressed. It is assumed that a unified solution that can be adapted to different processes and sensors would allow for greater flexibility, applicability, and thus transferability to different applications. To enable a flexible and intervention-independent system, this work proposes a concept for an adaptable situation recognition system. The system consists of four layers with several modular components for different functionalities. The feasibility is demonstrated via prototypical implementation and functional evaluation of a first basic framework prototype. Further development goal is the stepwise extension of the prototype.