The URO Mentor: development and evaluation of a new computer-based interactive training system for virtual life-like simulation of diagnostic and therapeutic endourological procedures

OBJECTIVE: To overcome the current disadvantages of traditional training methods for ureterorenoscopy and percutaneous nephrolitholapaxy, using the URO Mentor (Simbionix, Tel Aviv, Israel) computer-assisted simulator. METHODS: The URO Mentor device for training and quality control in ureterorenoscopy was developed using virtual reality, multimedia technology and intelligent tutoring systems. The central software system features a proprietary visualization engine (the SVE) which allows real-time simulation by offering a high-level object-orientated application program interface (written in C++) available for use with either Microsoft, DirectX 7 or OpenGL as platforms. The SVE includes general procedures to allow two- (2D) and three-dimensional (3D) rendering, collision detection, collision correction, 3D morphing, 2D image manipulation, texture mapping, 'bump' mapping, video texture, X-ray rendering, special effects (blood, smoke, stone fragments and more) and reflections. RESULTS: The system allows a complete training session on a wide range of procedures by offering different types of cases and virtual patients, and features a full representation of the endourological procedures under direct vision and by using interactive fluoroscopy with a contrast agent. The supported tools include: baskets, graspers, intracorporal lithotripters, guidewires, catheters, stents, biopsy and dilatation devices. The endourological procedures that can be performed are lithotripsy, tumour resection, treatment of strictures and obstructions, stent placement and biopsies. CONCLUSION: The URO Mentor introduces a new generation of mannequin equipped with a special haptic device, providing trainees with an unparalleled life-like sensation while training for diagnostic and therapeutic endourological procedures. By bringing key advances into urological simulation (e.g. with the real-time X-ray renderer) and by integrating in a single system both high-quality simulation and learning tools, the URO Mentor provides new perspectives for computer-based urological training systems and methods.     

Flexible ureterorenoscopy for the treatment of lower pole calyx stones: influence of different lithotripsy probes and stone extraction tools on scope deflection and irrigation flow

The 7.5 and 9.0 F flexible ureterorenoscopes are used widely in endourology. These scopes, along with new available tools and probes, enable intrarenal ureteroscopic access to renal stones in the lower pole. Following individual clinical experiences the infundibulopelvic angle has to be respected for the selection of different scopes, tools and probes. The aim of this study was to determine the influence of different scopes, tools and probes on the angle of the active and passive flexion of the flexible ureterorenoscope. The angles of the active and passive flexion and maximum irrigation flow of different flexible ureterorenoscope (9.0 F Wolf, 7.5 F Olympus, 7.5 F Storz) were measured repeatedly in vitro using nine different inserted tools and/or probes. In addition, the maximum allowing for easy passage of the nine different tools/probes through the channel of the scope were measured. The Olympus scope without working instrument present, allows for the greatest deflection. The flexible Lithoclast, the non-nitinol baskets, and the 365 microns laser probes significantly inhibit the deflection of all scopes. The greatest deflection with inserted working tool was possible using the Wolf and Storz scopes. Both nitinol tools as well as the 200 microns laser probe had only minimal influence on the deflection. The 200 microns laser probe reduces the irrigation flow from 50 to 28 ml/min. In contrast, the baskets reduce the irrigation flow from 50 to 2 ml/min. There are significant differences of the active and passive flexion depending on the ureterorenoscopes itself and the different tools. In order to perform a successful flexible ureterorenoscopic stone treatment in the lower pole, the inhibition of the flexion of the different scopes together with the individual infundibulopelvic angle must be respected when selecting different tools and probes.     

Validation of computer-based training in ureterorenoscopy

OBJECTIVES: To evaluate the outcome of training both urological novices and experts, using the recently developed UroMentor (Simbionix Ltd, Israel) trainer, that provides a realistic simulation of rigid and flexible ureterorenoscopy (URS). SUBJECTS AND METHODS: Twenty experienced urologists (total number of previous flexible URSs 21-153) were monitored during simulated flexible URS for treating a lower calyceal stone, and the outcome was correlated with individual experience. A score was compiled based on the variables recorded, including total operation time, stone contact time, complications such as bleeding or perforation, and treatment success. A further five urological residents with no endourological experience were trained on the UroMentor in rigid URS for ureteric stone treatment. Their acquired clinical skills were subsequently compared to those of five urological residents who received no simulator training. RESULTS: All 20 experienced urologists disintegrated the stone on the simulator, and the score achieved was related to their personal experience; there was a significant difference in performance in those with < 40 and > 80 previous flexible URSs. For the five urological residents with no endourological experience, simulator training improved their skills, and comparison with urological residents who had received no simulator training showed advantages for the trained residents. After being trained on the simulator, the group performed better in the first four URSs on patients. CONCLUSIONS: Individual experience correlates with individual performance on the simulator. Simulator training was helpful in improving clinical skills. Although the distribution of computer-based simulators is limited by high prices, virtual reality-based training has the potential to become an important tool for clinical education.     

Minimally invasive treatment of renal cell carcinoma: comparison of 4 different monopolar radiofrequency devices

OBJECTIVES: Radiofrequency Ablation is an investigational treatment option for RCC. The aim of our study was to test the ablation algorithms of four different RF systems in a standardized ex vivo perfused porcine kidney model. MATERIALS AND METHODS: A multiline monopolar dry electrode (impedance-based system), a multiline monopolar dry electrode (temperature-based system), a single monopolar wet electrode (impedance-based system) and a single monopolar dry, internally-cooled electrode (impedance-based system) were selected. RF energy was applied at different treatment parameters (power with and without control, tissue temperature, saline enhancement) for 1, 3, 5 and 9 minutes in healthy perfused ex vivo porcine tissue. Each treatment parameter was repeated 5 times. Maximum vertical, long-axis and short-axis diameters of the macroscopic lesion were measured and lesion volumes/ shapes were calculated. RESULTS: Lesion volumes increased significantly with the pre-selected tissue temperature and saline enhancement. Saline enhancement created larger, but irregular shaped lesions. The impedance-based system created lesion volumes that were predictable by treatment time and generator power. Lesions were unpredictable when uncontrolled generator power was applied. The created lesion shape was dependent on the selected electrode configuration. CONCLUSIONS: The currently available monopolar RFA systems offer different specific technical features to control tissue ablation. Detailed knowledge of the specific characteristics of each RF system is necessary to provide a higher chance of successful clinical outcome by complete and reliable ablation.     

Multiple high-intensity focused ultrasound probes for kidney-tissue ablation

BACKGROUND AND PURPOSE: To investigate kidney-tissue ablation by high-intensity focused ultrasound (HIFU) using multiple and single probes. MATERIALS AND METHODS: Ultrasound beams (1.75 MHz) produced by a piezoceramic element (focal distance 80 mm) were focused at the center of renal parenchyma. One of the three probes (mounted on a jig) could also be used for comparison with a single probe at comparable power ratings. Lesion dimensions were examined in perfused and unperfused ex vivo porcine kidneys at different power levels (40, 60, and 80 W) and treatment times (4, 6, and 8 seconds). RESULTS: At identical power levels, the lesions induced by multiple probes were larger than those induced by a single probe. Lesion size increased with increasing pulse duration and generator power. The sizes and shapes of the lesions were predictably repeatable in all samples. Lesions in perfused kidneys were smaller than those in unperfused kidneys. CONCLUSIONS: Ex vivo, kidney-tissue ablation by means of multiple HIFU probes offers significant advantages over single HIFU probes in respect of lesion size and formation. These advantages need to be confirmed by tests in vivo at higher energy levels.