Melanie Strake

Evaluation of a fluoroscopy-based navigation system enabling a virtual radiation-free preview of X-ray images for placement of cannulated hip screws. A cadaver study

Accurate placement of cannulated screws is essential to ensure fixation of medial femoral neck fractures. The conventional technique may require multiple guide wire passes, and relies heavily on fluoroscopy. A computer-assisted planning and navigation system based on 2D fluoroscopy for guide wire placement in the femoral neck has been developed to improve screw placement. The planning process was supported by a tool that enables a virtual radiation-free preview of X-ray images. This is called “zero-dose C-arm navigation”. For the evaluation of the system, six formalin-fixed cadaveric full-body specimens (12 femurs) were used. The evaluation demonstrated the feasibility of fluoroscopically navigated guide wire and implant placement. Use of the novel system resulted in a significant reduction in the number of fluoroscopic images and drilling attempts while achieving optimized accuracy by attaining better screw parallelism and enlarged neck-width coverage. Operation time was significantly longer in the navigation assisted group. The system has yielded promising initial results; however, additional studies using fractured bone models and with extension of the navigation process to track two bone fragments must be performed before integration of this navigation system into the clinical workflow is possible, and these studies should focus on reducing the operation time.

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.

Evaluation of a 2D Fluoroscopy-Based Navigation System for Insertion of the Dynamic Hip Screw (DHS): an Experimental Study

Ziel: Die Osteosynthese der lateralen Schenkelhalsfraktur mit einer dynamischen Hüftschraube (DHS) ist ein standardisiertes Verfahren. Ziel dieser Studie war die Evaluation eines neuen computergestützten Fluoroskopie-basierten Planungsund Navigationssystems mit neuartiger integrierter strahlungsfreier Röntgenbildvorschau (sog. „Zero-Dose C-Arm-Navigation“), das den Operateur bei der Implantation der DHS unterstützt. Material und Methoden: Von einem Operateur wurden in 24 intakte Kunstknochen 12 DHS navigiert und 12 DHS in konventioneller Technik implantiert. Beide Verfahren wurden je 6×offen und 6×geschlossen angewandt. Ergebnisse: Die Auswertung zeigte im Vergleich zum konventionellen Vorgehen eine signifikante Reduktion der Anzahl der Röntgenbilder mithilfe des Navigationsmoduls sowohl in der offen (–8,1 ±0,5; p <0,001) als auch in der geschlossen (–12,3 ±3,7; p <0,001) operierten Gruppe. An K-Draht-Bohrungen wurde in den beiden navigierten Gruppen bei jeder Durchführung jeweils nur 1 Versuch benötigt. Die konventionellen Versuchsreihen benötigten beide signifikant mehr Bohrungen (offen: + 1,3 ± 1,2; p <0,05 – geschlossen: + 1,5 ± 1,2; p <0,05). Bezüglich der Präzision ergaben sich keine signifikanten Unterschiede. Im Vergleich zur konventionellen Technik verlängerte sich die OP-Zeit signifikant in der offen navigiert operierten Gruppe (+ 14,6 ±5,4min; p<0,001) als auch in der geschlossen navigiert operierten Gruppe (+ 13±3min; p <0,001). Schlussfolgerung: Das computergestützte fluoroskopische Planungsund Navigationssystem ermöglicht eine intraoperative Planung und sichere und reproduzierbare Umsetzung dieser Planung bei der Implantation der DHS. Vorteile sind die deutliche Reduktion der Strahlenbelastung und der Bohrungen bei gleich bleibender Präzision im Vergleich zum konventionellen Vorgehen. KriAbstract !

Evaluation of a new computer-assisted surgical planning and navigation system based on two-dimensional fluoroscopy for insertion of a proximal femoral nail: an experimental study.

Pertrochanteric femoral fractures are common and intramedullary nailing is an accepted method for their surgical treatment. Accurate placement of the implant is essential to ensure fixation. The conventional technique can require multiple guide wire passes, and relies heavily on fluoroscopy. A computer-assisted planning and navigation system based on two-dimensional fluoroscopy for guide wire placement in the femoral neck has been developed, in order to perform intramedullary pertrochanteric fracture fixation using the proximal femoral nail (PFNA®). The planning process was supported by a ‘zero-dose C-arm navigation’ system. The PFNA was inserted into 12, intact, femoral sawbones guided by the computer-based navigation, and into 12, intact, femoral sawbones using a conventional fluoroscopic-assisted technique. Guide wire and subsequent blade placement in the femoral neck was evaluated. The computer-assisted technique achieved a significant decrease in the number of required fluoroscopic images and in the number of guide wire passes. The obtained average blade placement accuracy in the femoral neck was equivalent to the conventional technique. The operation time was significantly longer in the navigation-assisted group. The addition of computer-assisted planning and surgical guidance to the intramedullary nailing of pertrochanteric femoral fractures offers a number of clinical benefits based on the results of this sawbone study. Further studies including fractured sawbones and cadaver models with extension of the navigation process to all steps of PFNA introduction and with the goal of reducing operation time are indispensable before integration of this navigation system into clinical practice.