Development and validation of a virtual reality transrectal ultrasound guided prostatic biopsy simulator

Abstract

Objective: We present the design, reliability, face, content and construct validity testing of a virtual reality simulator for transrectal ultrasound (TRUS), which allows doctors-in-training to perform multiple different biopsy schemes. Methods: This biopsy system design uses a regular "end-firing" TRUS probe. Movements of the probe are tracked with a micromagnetic sensor to dynamically slice through a phantom patient's 3D prostate volume to provide real-time continuous TRUS views. 3D TRUS scans during prostate biopsy clinics were recorded. Intrinsic reliability was assessed by comparing the left side of the prostate to the right side of the prostate for each biopsy. A content and face validity questionnaire was administered to 26 doctors to assess the simulator. Construct validity was assessed by comparing notes from experts and novices with regards to the time taken and the accuracy of each biopsy. Results: Imaging data from 50 patients were integrated into the simulator. The completed VR TRUS simulator uses real patient images, and is able to provide simulation for 50 cases, with a haptic interface that uses a standard TRUS probe and biopsy needle. Intrinsic reliability was successfully demonstrated by comparing results from the left and right sides of the prostate. Face and content validity respondents noted the realism of the simulator, and its appropriateness as a teaching model. The simulator was able to distinguish between experts and novices during construct validity testing. Conclusions: A virtual reality TRUS simulator has successfully been created. It has promising face, content and construct validity results. IntroductionThe current gold standard and the most widely used method to diagnose prostate cancer is transrectal ultrasound (TRUS)-guided prostatic biopsy, which is commonly performed in Westernized high income countries. For instance, in Australia in 2008 a total of 26 146 TRUS guided biopsies of the prostate were performed. 1Transrectal ultrasound-guided prostatic biopsy does have well-documented complications. A recently published Japanese nationwide survey of more than 200 000 prostatic biopsies revealed that complications occurred frequently, with hematuria in 12%, hematochezia in 5.9%, hematospermia in 1.2%, fever in 1.1%, sepsis in 0.07%, voiding symptoms in 1.9%, urinary retention in 1.1% and prostatitis in 0.9%. Hospitalization to treat complications occurred in 0.69% of the entire cohort.2 Mortality rates at 120 days of 1.3% have been also been reported from a cohort of 22 175 patients by Gallina and colleagues.

Ensuring Competency in Open Aortic Aneurysm Repair – Development and Validation of a New Assessment Tool

“…Other studies have also shown that experienced physicians tend to score low during simulation assessment due to a degree of unfamiliarity and lack of realism of the simulation equipment used. 26,27 Setting standards or a credible pass/fail score for performance is an essential asset of a test 12,28,29 and its application is progressively required in competency based learning, especially for procedural assessment. 30,31 Validity evidence for consequences of testing was gathered using the Angoff method to define a passing score.…”