Armin Janß

User-Interaction of a Semiautomatic Trepanation System

During trepanation, a neurosurgical procedure for opening the skull, the protection of the underlying dura mater and a minimized loss of bone are major concerns. A concept for a novel trepanation system has been developed in order to open the skull less invasively and more safely. This trepanation system is based on a soft tissue preserving cutting tool and an autonomous control of the cutting depth.

Cognitive task analysis for prospective usability evaluation in computer-assisted surgery

Within the framework of the INNORISK (Innovative Risk Analysis Methods for Medical Devices) project, a twofold strategy is pursued for prospective usability assessment of Computer-Assisted Surgery (CAS) systems in the context of a risk management process. In one approach ConcurTaskTrees are applied to accomplish a hierarchical task analysis including temporal relations. In the other approach, based on the Cognitive Task Analysis method CPM-GOMS (Cognitive Perceptual Motor - Goals Operators Methods Selection Rules), a new technique for detecting potential contradictions and conflicts in the use of concurrent cognitive resources is generated. Within this model-based approach, extrinsic and intrinsic performance shaping factors are comprised, taking into account the specific context of modern surgical work systems. Additionally, a computer assisted usability analysis tool including the above-mentioned methods is developed to provide support for small and medium-sized enterprises in early stages of the design development process of risk sensitive Human-Machine-Interfaces in medical systems.

Bottlenecks and needs in human-human and human-machine interaction – a view from and into the neurosurgical OR

Abstract The number and complexity of user interfaces in the OR has been considerably increasing during the last years. Moreover, increasing cost and time pressure force surgeons and surgical nurses to perform different tasks in parallel. We analyzed the workflow of 25 neurosurgical procedures with a workflow analysis tool in order to analyze the present situation in the neurosurgical OR and to identify potential use-oriented risks and to develop first proposals for respective countermeasures. Application of the navigation system, the CUSA ultrasonic aspirator, and the PACS-PC was associated with errors and resulting potential risks. A number of different disruptive factors have been identified, the most prominent of those being intraoperative duty phone calls, longer absence of the circulating nurses or slipped off foot switches. Furthermore, the identified problems may lead to risks for patient, and also for staff by use errors, associated with an inappropriate cognitive workload of the surgeon or nurses. Organizational and technical countermeasures are necessary: to enhance communication, team trainings could be helpful, and the setup of a mailbox could reduce the number of intraoperative duty phone calls. Technical deficiencies have to be reduced, e.g. with more user-oriented design of devices, such as foot switches, or standard design for user interfaces. For further risk reduction in the case of use deficiencies, we propose the implementation of device interoperability and the use of a sterile integrated user interface in a networked OR.

A Configurable Footswitch Unit for the Open Networked Neurosurgical OR - Development, Evaluation and Future Perspectives

Abstract Footswitches are used in the neurosurgical operating room for human-device-communication every day. However, problems, such as shifting or confusion of footswitches, often occur due to the parallel usage of up to 5 device-specific footswitches, resulting in a significant burden for the surgeon. There are no footswitches available which offer an optional central activation of different devices from various manufacturers and a reconfiguration during usage. Therefore, a new concept of a configurable central footswitch unit has been developed for optional activation of different devices in an open networked neurosurgical OR setting. In a user-centered evaluation 9 surgeons used both, the configurable central footswitch unit and 4 device-specific footswitches, for a cross-over experiment in an experimental OR setting. It shows that all surgeons were able to handle the configurable footswitch autonomously and that efficiency in surgeon-device-communication can be increased.

Human-centered risk management for medical devices – new methods and tools

Abstract Studies regarding adverse events with technical devices in the medical context showed, that in most of the cases non-usable interfaces are the cause for use deficiencies and therefore a potential harm for the patient and third parties. This is partially due to the lack of suitable methods for interlinking usability engineering and human-centered risk management. Especially regarding the early identification of human-induced errors and the systematic control of these failures, medical device manufacturers and in particular the developers have to be supported in order to guarantee reliable design and error-tolerant human-machine interfaces (HMI). In this context, we developed the HiFEM methodology and a corresponding software tool (mAIXuse) for model-based human risk analysis. Based on a two-fold approach, HiFEM provides a task-type-sensitive modeling structure with integrated temporal relations in order to represent and analyze the use process in a detailed way. The approach can be used from early developmental stages up to the validation process. Results of a comparative study with the HiFEM method and a classical process-failure mode and effect analysis (FMEA) depict, that the new modeling and analysis technique clearly outperforms the FMEA. Besides, we implemented a new method for systematic human risk control (mAIXcontrol). Accessing information from the method’s knowledge base enables the operator to detect the most suitable countermeasures for a respective risk. Forty-one approved generic countermeasure principles have been indexed as a resulting combination of root causes and failures in a matrix. The methodology has been tested in comparison to a conventional approach as well. Evaluation of the matrix and the reassessment of the risk priority numbers by a blind expert demonstrate a substantial benefit of the new mAIXcontrol method.

Modular user interface design for integrated surgical workplaces

Abstract Severe bottlenecks in usability and human technology interaction (HTI) of existing surgical workplaces and operating room (OR) equipment can occur today: lack of space, cable as trip hazard, communication problems between sterile and non-sterile staff, and operating errors in the handling of the medical devices. In fact, risks that are caused by poor usability can be critical, and studies show that most are preventable. This issue gets even more challenging in the context of open-OR networks regarding consistent and usable integration of user interfaces (UIs) of independently designed systems in one integrated surgical work system. In this work, a concept of generic UI profiles for the modular integration of a UI has been developed and first prototypes have been implemented. The concept is essentially based on the approach of device profiles developed in the context of the Bundesministerium für Bildung und Forschung project OR.NET (www.ornet.org). We developed generic UI profiles to map the different interfaces of the medical devices on an integrated surgical UI. The integrated UI design shall be automatically verified according to agreed usability criteria, guidelines, and human error taxonomies.

Development and experimental evaluation of an alarm concept for an integrated surgical workstation

Abstract Introduction: Alarm conditions of the technical equipment in operating rooms represent a prevalent cause for interruptions of surgeons and scrub nurses, resulting in an increase of workload and potential reduction of patient safety. In this work, an alarm concept for an integrated operating room system based on open communication standards is developed and tested. Methods: In a laboratory experiment, the reactions of surgeons were analysed, comparing the displaying of alarms on an integrated workstation and on single devices: disruptive effects of alarm handling on primary task (ratings of perceived distraction, resumption lag, deterioration of speed, accuracy, and prospective memory), efficiency and effectiveness of identification of alarms, as well as perceived workload were included. Results: The identification of the alarm cause is significantly more efficient and effective with the integrated alarm concept. Moreover, a slightly lower deterioration of performance of the primary task due to the interruption of alarm handling was observed. Conclusion: Displaying alarms on an integrated workstation supports alarm handling and consequently reduces disruptive effects on the primary task. The findings show that even small changes can reduce workload in a complex work environment like the operating room, resulting in improved patient safety.

From SOMDA to application – integration strategies in the OR.NET demonstration sites

Abstract The effective development and dissemination of the open integration for the next generation of operating rooms require a comprehensive testing environment. In this paper, we present the various challenges to be addressed in demonstration applications, and we discuss the implementation approach, the foci of the demonstration sites and the evaluation efforts. Overall, the demonstrator setups have proven the feasibility of the service-oriented medical device architecture (SOMDA) and real-time approaches with a large variety of example applications. The applications demonstrate the potentials of open device interoperability. The demonstrator implementations were technically evaluated as well as discussed with many clinicians from various disciplines. However, the evaluation is still an ongoing research at the demonstration sites. Technical evaluation focused on the properties of a network of medical devices, latencies in data transmission and stability. A careful evaluation of the SOMDA design decisions and implementations are essential to a safe and reliable interoperability of integrated medical devices and information technology (IT) system in the especially critical working environment. The clinical evaluation addressed the demands of future users and stakeholders, especially surgeons, anesthesiologists, scrub nurses and hospital operators. The opinions were carefully collected to gain further insights into the potential benefits of the technology and pitfalls in future work.

Extended device profiles and testing procedures for the approval process of integrated medical devices using the IEEE 11073 communication standard

Abstract Nowadays, only closed and proprietary integrated operating room systems (IORS) from big manufacturers are available on the market. Hence, the interconnection of components from third-party vendors is only possible with increased time and costs. In the context of the German Federal Ministry of Education and Research (BMBF)-funded project OR.NET (2012–2016), the open integration of medical devices from different manufacturers was addressed. An integrated operating theater based on the open communication standard IEEE 11073 shall give clinical operators the opportunity to choose medical devices independently of the manufacturer. This approach would be advantageous especially for hospital operators and small- and medium-sized enterprises (SME) of medical devices. Actual standards and concepts regarding technical feasibility and the approval process do not cope with the requirements for a modular integration of medical devices in the operating room (OR), based on an open communication standard. Therefore, innovative approval strategies and corresponding certification and test procedures, which cover actual legal and normative standards, have to be developed in order to support the future risk management and the usability engineering process of open integrated medical devices in the OR. The use of standardized device and service profiles and a three-step testing procedure, including conformity, interoperability and integration tests are described in this paper and shall support the manufacturers to integrate their medical devices without disclosing the medical devices’ risk analysis and related confidential expertise or proprietary information.

Further Development and Evaluation of a Universal Foot Switch for Diverse Medical Disciplines within the Framework of an Open Integration Concept for the Operation Theatre of the Future

In nowadays medical environment, foot switches are used in almost every operating theatre as one option to enable the interaction with medical devices. The increasing number of devices controlled by foot switches and the complexity of those devices challenge the surgeon regarding the usability and safety of human-machine-interfaces. The approach of the presented paper was to further develop and evaluate a universal foot switch and its corresponding graphical user interface for diverse medical disciplines for an open integrated operating theatre. As results of the user-centred design and evaluation process, it can be said that the fulfilment of the requirements for various medical disciplines has been challenging due to the specific required devices and tasks. Although a universal footswitch has been developed and evaluated positively, the concept of a specific universal foot switch for each discipline could be an alternative to face the identified challenge of complexity.