Integrating medical devices in the operating room using service-oriented architectures.

Abstract With the increasing documentation requirements and communication capabilities of medical devices in the operating room, the integration and modular networking of these devices have become more and more important. Commercial integrated operating room systems are mainly proprietary developments using usually proprietary communication standards and interfaces, which reduce the possibility of integrating devices from different vendors. To overcome these limitations, there is a need for an open standardized architecture that is based on standard protocols and interfaces enabling the integration of devices from different vendors based on heterogeneous software and hardware components. Starting with an analysis of the requirements for device integration in the operating room and the techniques used for integrating devices in other industrial domains, a new concept for an integration architecture for the operating room based on the paradigm of a service-oriented architecture is developed. Standardized communication protocols and interface descriptions are used. As risk management is an important factor in the field of medical engineering, a risk analysis of the developed concept has been carried out and the first prototypes have been implemented.

The impact of microsurgery, stereotactic radiosurgery and radiotherapy in the treatment of meningiomas depending on different localizations.

SCIENTIFIC BACKGROUND: Meningiomas are the most common benign intracranial neoplasms with a slow growth presented as the intracranial lesion. These tumors are without any symptoms for a long time. At the time of diagnosis it is frequently an asymptomatic tumor. In that case the therapist may well suggest a wait-and-see strategy. The therapy of meningiomas focuses firstly on the microsurgical treatment. Volume reduction can be achieved immediately after treatment. Stereotactic radiosurgery is an important non-invasive treatment option for recurrent tumors or meningiomas with partial resection. The technical equipment for the stereotactic radiosurgery is a cost intensive investment. In this context the high precision of the intervention, presented as a low invasiveness of the treatment, is an important factor. The aim of this assessment is to identify the chances and limitations of the diverse treatment options and to estimate their outcome for different localisations of meningiomas. METHODS: In December 2007 a systematic literature search was conducted using the most relevant medical databases. The whole strategy and the used search terms were documented. The literature search was supplemented with an internet and literature based hand search on law, ethics and economics. Primary studies and systematic reviews which report relevant outcomes are included in this analysis. The current assessment is based on the available evidence that was found at the time of the literature search. RESULTS: A total of 31 publications for the medical focus of assessment and three reports from the economical hand search were included. In general, it is not possible to identify neither randomised clinical trials or prospective, contrasting cohort studies nor studies summarising results from such studies. The results presented in the literature published by surgeons strongly vary regarding localisation of meningiomas. Publications not differentiating between the localisation of meningiomas indicate a progression free survival rate of five years in 77 to 97% of the cases after complete surgical resection of the tumor, in 18 to 70% of the cases after subtotal resection and for patients who had undergone surgical resection and a combined radiotherapeutical treatment of their meningiomas a five year progression free survival rate between 82 and 97%. Other treatment options like hormone therapy or treatments to stop tumor growth had been used unsuccessfully so far. Based on the results presented regarding economic evaluation, costs resulting from radiosurgical treatment are lower in contrast to costs resulting from surgical resection. However, it has to be taken into account that costs resulting from radiosurgical treatment strongly depend on the number of patients treated in total with the radiosurgical equipment. CONCLUSION: Due to the strong dependencies between the results from surgical therapy and the localisation of the tumor, it is only possible to derive recommendations on whether or not to perform the surgical therapy with respect to the localisation of the tumor. Only for patients with tumors with a spinal localisation or WHO Grade I meningiomas with a cortical localisation, primary treatment with by means of microsurgery can be suggested. For all other localisations of the tumor, alternative treatment by radiosurgery should be discussed. From the literature identified, a clear recommendation of one or the other therapy however can not be deduced. Thus, there is a strong need for randomised clinical trials or prospective or contrasting cohort studies, which compare rigorously microsurgery with radiosurgery concerning different localisations of tumors.

Invasive home mechanical ventilation, mainly focused on neuromuscular disorders.

INTRODUCTION AND BACKGROUND: Invasive home mechanical ventilation is used for patients with chronic respiratory insufficiency. This elaborate and technology-dependent ventilation is carried out via an artificial airway (tracheal cannula) to the trachea. Exact numbers about the incidence of home mechanical ventilation are not available. Patients with neuromuscular diseases represent a large portion of it. RESEARCH QUESTIONS: Specific research questions are formulated and answered concerning the dimensions of medicine/nursing, economics, social, ethical and legal aspects. Beyond the technical aspect of the invasive home, mechanical ventilation, medical questions also deal with the patient's symptoms and clinical signs as well as the frequency of complications. Economic questions pertain to the composition of costs and the differences to other ways of homecare concerning costs and quality of care. Questions regarding social aspects consider the health-related quality of life of patients and caregivers. Additionally, the ethical aspects connected to the decision of home mechanical ventilation are viewed. Finally, legal aspects of financing invasive home mechanical ventilation are discussed. METHODS: Based on a systematic literature search in 2008 in a total of 31 relevant databases current literature is viewed and selected by means of fixed criteria. Randomized controlled studies, systematic reviews and HTA reports (health technology assessment), clinical studies with patient numbers above ten, health-economic evaluations, primary studies with particular cost analyses and quality-of-life studies related to the research questions are included in the analysis. RESULTS AND DISCUSSION: Invasive mechanical ventilation may improve symptoms of hypoventilation, as the analysis of the literature shows. An increase in life expectancy is likely, but for ethical reasons it is not confirmed by premium-quality studies. Complications (e. g. pneumonia) are rare. Mobile home ventilators are available for the implementation of the ventilation. Their technical performance however, differs regrettably. Studies comparing the economic aspects of ventilation in a hospital to outpatient ventilation, describe home ventilation as a more cost-effective alternative to in-patient care in an intensive care unit, however, more expensive in comparison to a noninvasive (via mask) ventilation. Higher expenses arise due to the necessary equipment and the high expenditure of time for the partial 24-hour care of the affected patients through highly qualified personnel. However, none of the studies applies to the German provisionary conditions. The calculated costs strongly depend on national medical fees and wages of caregivers, which barely allows a transmission of the results. The results of quality-of-life studies are mostly qualitative. The patient's quality of life using mechanical ventilation is predominantly considered well. Caregivers of ventilated patients report positive as well as negative ratings. Regarding the ethical questions, it was researched which aspects of ventilation implementation will have to be considered. From a legal point of view the financing of home ventilation, especially invasive mechanical ventilation, requiring specialised technical nursing is regulated in the code of social law (Sozialgesetzbuch V). The absorption of costs is distributed to different insurance carriers, who often, due to cost pressures within the health care system, insurance carriers, who consider others and not themselves as responsible. Therefore in practice, the necessity to enforce a claim of cost absorption often arises in order to exercise the basic right of free choice of location. CONCLUSION: Positive effects of the invasive mechanical ventilation (overall survival and symptomatic) are highly probable based on the analysed literature, although with a low level of evidence. An establishment of a home ventilation registry and health care research to ascertain valid data to improve outpatient structures is necessary. Gathering specific German data is needed to adequately depict the national concepts of provision and reimbursement. A differentiation of the cost structure according to the type of chosen outpatient care is currently not possible. There is no existing literature concerning the difference of life quality depending on the chosen outpatient care (homecare, assisted living, or in a nursing home specialised in invasive home ventilation). Further research is required. For a so called participative decision - made by the patient after intense counselling - an early and honest patient education pro respectively contra invasive mechanical ventilation is needed. Besides the long term survival, the quality of life and individual, social and religious aspects have also to be considered.

A software framework for the development of Web-based medical education using learning object classes.

A software framework for the development of Web-based medical education is proposed. The objective is to optimize the development process by introducing Learning Objects (LO) and Learning Object Classes (LO Classes) so that the content preparation can be separated from the educational issues, ergonomic design, and technical realization. Based on the concept of case-based, problem-oriented education, different learning scenarios were analysed and then modelled as different LOs. These LOs can be further abstracted in several reusable LO Classes that represent certain patterns of content structure, pedagogical concept, and user interface. With the help of LO input templates, the educational material can be prepared by the authors in the authoring process easily and appropriately. An LO content management system was developed to store and maintain different LOs and to generate the Web-presentation of LOs adaptively and dynamically in the tutoring process. This software framework has been applied to the exemplary development of an interactive course in orthopaedics. The LOs and LO Classes also help to maintain consistency of the course representation to users. As a result, more efficiency in the development phase and good usability and quality of the end products can be achieved.

Assessment of video tracking usability for training simulators.

OBJECTIVE: A simulator was developed to mimic commercial CAS systems in implementing most tasks required to carry out a surgical operation. As tracking systems are generally expensive components, an alternative solution based on low-cost video-based tracking was used. Video tracking accuracy was assessed to determine whether or not this kind of approach was suitable for use in the training domain. Ultimately, video-based tracking should enable sufficiently accurate registration between a bony model and its virtual 3D representation. MATERIALS AND METHODS: Video tracking was assessed using two types of camera. For each one, common accuracy tests were realized as a series of 10 trials at ranges of 0.5-1.0 m from the camera lens. The pointer used as a digitizer was equipped with tracked video markers. Three sizes of marker were evaluated to estimate the impact of marker size on accuracy. RESULTS: For the better of the two cameras tested, results were encouraging. Results are presented as rounded whole-number values in millimeters. The noise test gave accuracies of 2 mm for the 80-mm marker, 3 mm for the 60-mm marker and 5 mm for the 40-mm marker. Relative accuracies, as evaluated on a grid of equally spaced dots, were 4 mm with the 80-mm marker, 7 mm with the 60-mm marker and 12 mm with the 40-mm marker. A pivoting test around the pointer tip gave 3 mm of accuracy for the 80-mm marker, 5 mm for the 60-mm marker and 11 mm for the 40-mm marker. An additional pivoting test was completed on increasing the distance of the marker from the pointer tip, giving accuracies of 5 mm for the 80-mm marker, 6 mm for the 60-mm marker and 13 mm for the 40-mm marker. The registration test gave accuracies of 8 mm for the 80-mm marker, 9 mm for the 60-mm marker and 11 mm for the 40-mm marker. CONCLUSIONS: The video-based approach offers sufficient accuracy to achieve registration in the domain of CAS training.