The virtual reality endourologic simulator is realistic and useful for educational purposes.

PURPOSE: To examine the educational value of URO Mentor, a virtual reality simulator for endourologic procedures, by establishing its face and content validity. MATERIALS AND METHODS: Eighty-nine urologists and residents in urology performed a urethrocystoscopy task (bladder inspection, biopsy, and coagulation) or a ureterorenoscopy task (manipulation of a distal ureter stone) using the URO Mentor. They completed an evaluation questionnaire about these tasks. Questionnaire bias related to task performance on URO Mentor was analyzed as well (Hawthorne effect). RESULTS: The overall rating of the URO Mentor was 7.3 on a 10-point scale (1 = poor, 10 = excellent). Regression analysis showed that ratings were not related to previous experience or task performance using the URO Mentor. Of all subjects, 25% rated the realism of URO Mentor as >or=3.5 on a five-point scale, and 82% rated its usefulness as an educational tool as >or=3.5 on a five-point scale. More than 73% of all participants said they would purchase a URO Mentor if financial means were available; participants who needed more time to complete the task were less positive in their answers to this question. CONCLUSIONS: URO Mentor appears to be a realistic and useful training model for endourologic procedures.

The use of endoluminal ultrasonography for preventing significant bleeding during endopyelotomy: evaluation of helical computed tomography vs endoluminal ultrasonography for detecting crossing vessels.

OBJECTIVE: To evaluate, in a prospective study, the efficiency of helical computed tomography (CT) and endoluminal ultrasonography (ELUS) for detecting significant crossing vessels, a major cause of bleeding complications when treating patients with pelvi-ureteric junction (PUJ) obstruction, and to compare our results using ELUS with those of an earlier multicentre study (not using ELUS), to see whether the complication rate decreased. PATIENTS AND METHODS: The study included 27 patients with a PUJ who had isotope renography, intravenous urography, helical CT and ELUS before surgery. Depending on the findings of ELUS, patients were treated with a pure lateral Acucise incision (Applied Medical, Irvine, CA, USA) an Acucise with changed cutting direction, or (later) a laparoscopic pyeloplasty. RESULTS: ELUS detected 15% more crossing vessels than helical CT; 16 patients had Acucise (seven lateral, nine other cutting direction), eight were treated with a laparoscopic pyeloplasty and three with other procedures. By contrast with earlier reports and as a consequence of using ELUS, there was no bleeding, vs 16% in the study not using ELUS. The success rate of 73% of the endourological approach is comparable with previous reports. CONCLUSION: ELUS is more sensitive in detecting relevant crossing vessels than helical CT and therefore the use of ELUS can better prevent bleeding complications. ELUS can also improve the success rate by helping in selecting the correct treatment. Because it is minimally invasive and safe, ELUS combined with Acucise (or other possible endourological techniques, like holmium laser incision) should be the first choice of treatment for PUJ stenosis.

Noninvasive assessment of blood pressure variability in preterm infants.

The feasibility of measuring blood pressure (BP) variability by a noninvasive beat-to-beat finger arterial BP device (Finapres) was assessed in preterm infants. By application of the finger cuff around the infant's wrist, time and frequency domain (spectral power) analysis of noninvasive beat-to-beat BP signals were compared with intra-arterial measurements. A fast Fourier Transform was used to compute the spectral power density from 128-s periods. The low-frequency band (LF; 0.04-0.15 Hz) is partly associated with baroreflex activity. The high-frequency band (HF; 0.4-1.5 Hz) is associated with respiratory activity. In eight subjects above 1000 g, reliable signals could be obtained. We observed a high correlation between noninvasive and intra-arterial beat-to-beat systolic BP values (mean r value +/- SD, 0.87 +/- 0.11), with a gain close to 1 (mean gain +/- SD, 1.0 +/- 0.4 mm Hg/mm Hg). Finapres estimated beat-to-beat systolic BP changes more accurately than diastolic values. We found a very high amount of linear coupling, expressed as coherence function, between the power spectra of noninvasive and intra-arterial systolic BP measurements. For systolic BP, the (pooled) group mean +/- SEM coherence values were 0.93 +/- 0.00 and 0.91 +/- 0.01 for LF and HF fluctuations, respectively (NS). The wrist method of Finapres in neonates has limited value in estimating absolute BP but is useful in a clinical research situation, where identification of beat-to-beat changes in systolic BP is more important. Finapres provides a noninvasive tool for investigating autonomic cardiovascular regulation (baroreflex sensitivity, spectral analysis of BP fluctuations) in neonates.