Validation of percutaneous nephrostomy (PCN) performed using the PercMentor® simulator.

Abstract

INTRODUCTION: The traditional method of acquiring procedural skills is by apprenticeship and involves an extensive period of training with patients. Model-based and virtual reality simulation is gaining interest as alternative training, allowing repetitive practice in a low-risk, trainee focused and safe environment. The objective of this study was to prospectively validate percutaneous nephrostomy (PCN) training using the PercMentor® simulator. The study concentrated on assessing construct validity (the ability of the training system to differentiate trainees according to their clinical experience) and on getting experts opinion on the training modality. MATERIALS AND METHODS: 4 groups of 10 medical doctors each participated in the study :1) novices, 2) radiology residents, 3) radiology fellows and 4) board certified invasive radiologists. Following a structured introduction to the procedure and to the simulation system, each participant performed the following tasks: 1) recognition of anatomic structures without fluoroscopy, 2) and with fluoroscopy, 3) calices recognition with fluoroscopy, 4) balloon puncturing, and 5) 2 clinical PCN free training tasks. Evaluation parameters included: time to task completion, fluoroscopy time, contrast volume used, and the number of balloons punctured over a 5 minute period. At the end of the training participants were asked to fill in a subjective questionnaire regarding the training modality. RESULTS: Construct validity of task performance was demonstrated in most parameters. Time to task completion in the recognition of the spleen without fluoroscopy in groups 1), 2), 3) and 4) was 109±61, 56±28, 28±15, 18±7 (mean±SD) seconds, respectively (F(3,36)=8.3, p<0.00); and with fluoroscopy 103±42, 56±42, 32±20, 22±10 seconds, respectively. The total time for calices recognition was 337±105, 241±58, 154±37, and 117±37 seconds (F(3,36)=12.8, p<0.00). Time to task completion of the first free PCN task was 175±27, 187±76, 99±38, 36±24 seconds (F(3,35)=22.8, p<0.00), and for the second free PCN task 103±40, 101±64, 41±14, 30±17 seconds (F(3,36)=9.7, p<0.00). Contrast material volume used in the first task was 42±13, 44±22, 21±9, 9±6 ml (F(3,36)=14.8, p<0.00) and for the second task 22±9, 16±6, 9±9, 9±5 ml. The number of balloons punctured over 5 minutes period was 4±1, 5±1, 6±1, 7±0. The board certified radiologists recommended using the simulator as a teaching tool for residents in invasive radiology (mean score of 6 on a 1–6 scale), and indicated that the imaging achieved by the simulation system is similar to real imaging (score 5±1). The experts indicated that the catheters used are not fully similar to real catheters and that the haptic of working with the simulation system not fully resembles the haptic of human tissues (both scored as 3±1). CONCLUSION: In this study construct validity of the simulation training system was demonstrated and experts recommended its use for training of fellows in invasive radiology. This information is crucial for the validation of the training system but the benefits of training using the simulation system on actual clinical performance remains to be proved.