A computer-assisted training/monitoring system for TURP structure and design

COMPUTER ASSISTED PROSTATE SURGERY TRAINING

We report the current development of a new computer assisted system for local and remote training of transurethral resection of the prostate (TURP). The system is based on a 3D computer model of the prostate gland, which simulates deformations and resections of prostatic tissue. Simulated resections of the prostate can be repeatedly performed by the residents of urology to enhance their training. Automatic prostate recognition software was developed for the construction of a large library of prostate models. We report the software development of the system and show promising preliminary results of a new prostate recognition algorithm.

Face and content validity of transurethral resection of prostate on Uro Trainer: is the simulation training useful?

BACKGROUND

Uro Trainer (UT; Karl Storz GmbH, Tuttlingen, Germany), a virtual reality simulator for transurethral resection of prostate (TURP), has been infrequently validated. To ascertain the utility of such a trainer, we performed a basic face and content validity study.

MATERIALS AND METHODS

Ten experts and nine novices (done more than 50 and less than 3 TURPs, respectively) performed a TURP on UT and rated simulator usefulness (seven items), realism (five items), and overall score (one item) on a Likert's 10-point scale. Scores of < 6.0, 6.0 to 8.0, and > 8.0 on the Likert scale 1 to 10 were considered not, slightly, and highly acceptable, respectively.

RESULTS

Novices rated UT as more helpful than experts in the following aspects of face and content validity: usefulness general (p = 0.0001, statistically significant), hand-eye coordination (p = 0.04, statistically significant), material knowledge and skills (p = 0.02, statistically significant), spatial skills (p = 0.003, statistically significant), cystoscopy (p = 0.002, statistically significant), TURP (0.002, statistically significant), visual aspects (p = 0.003, statistically significant), and overall score (p = 0.007, statistically significant). One item of usefulness (coagulation) and three items of realism (tissue feel, depth feel, and capsule identification) failed to impress both novice and experts. UT usefulness domain was highly acceptable for 77.7% and slightly acceptable for 100% of the novices and experts, respectively. The general realism domain was highly and slightly acceptable for 33.3% and 66.6% of the novices while slightly acceptable for 100% of the experts.

CONCLUSION

Novice group found UT more useful than the experts group. Further modification is advisable to increase the realism of the UT.

"Homemade" TUR-simulator for less than $40 U.S.? The "Tupper" experience

INTRODUCTION

Transurethral surgery is important in daily urologic life. In training residents it is important to develop resection skills. We introduce a homemade simulator to improve capabilities for the training of transurethral procedures.

MATERIALS AND METHODS

Material consists of 7 cm of a 30F garden hose, a suprapubic tube, a Tupperware box (Frankfurt, Germany), three catheter plugs, and silicone gel. Cost of materials is below $40 U.S. Transurethral procedures such as mono- and bipolar resection and RevoLix laser vaporesection were carried out. Different meat types were tested to develop a close to real resection feeling. Further, flexible cystoscopy was trained with the simulator. Multiple markings were placed inside the box. These markings had to be identified by flexible cystoscopy. The time to completion of this task was recorded.

RESULTS

Transurethral resection and flexible cystoscopy is feasible. Pork and beef lead to a realistic feeling compared with transurethral resection. For laser surgery, pork and chicken seem to be most realistic. Further, confidence in flexible cystoscopy could be obtained. During the flexible cystoscopy task, an average time reduction of 50.96% could be achieved.

CONCLUSION

This cheap and simple resection simulator allows easy training of lower urinary tract procedures. It helps young urologists to acquire basic endourologic skills. It may be beneficial for residents in the process of learning lower urinary tract surgery. Further, new techniques can be trained and may lead to a decreased risk for the patients.

How useful and realistic is the uro trainer for training transurethral prostate and bladder tumor resection procedures?

PURPOSE

We evaluated the face and content validity (novice and expert opinions of realism and usefulness) of the Uro Trainer (Karl Storz GmbH, Tuttlingen, Germany), a simulator for transurethral resection procedures, to ascertain whether it is justifiable to continue the validation process by performing prospective experimental studies.

MATERIALS AND METHODS

Between 2006 and 2008, 104 urologists and urology residents performed a transurethral bladder tumor resection and/or transurethral prostate resection procedure on the Uro Trainer, and rated simulator usefulness and realism on a 10-point scale (1-not at all useful/realistic/poor, 10-very useful/realistic/excellent). Participants were classified as experts (more than 50 procedures performed) or novices (50 or fewer procedures performed). Because the literature offered no guidelines for interpreting our data, we used criteria from other studies to interpret the results.

RESULTS

A total of 161 questionnaires were analyzed from 97 (21% experts, 79% novices) and 64 (30% experts, 70% novices) participants who performed transurethral prostate resection and transurethral bladder tumor resection procedures, respectively. Mean usefulness, realism and overall scores varied from 5.6 to 8.2 (SD 1.4-2.5). Measured by validity criteria from other studies, Uro Trainer face and content validity was unsatisfactory, with ratings on only 3%, 5% and 8% of the parameters interpreted as positive, moderately acceptable and good, respectively.

CONCLUSIONS

Measured against criteria from other validation studies, Uro Trainer face and content validity appears to be unsatisfactory. Modification of the simulator seems advisable before further experimental validation studies are initiated. The lack of general guidelines for establishing face and content validity suggests a need for consensus about appropriate methods for evaluating the validity of simulators.

Update on training models in endourology: a qualitative systematic review of the literature between January 1980 and April 2008

CONTEXT

Interest in the use of simulators in urological skills training is on the increase. To ensure effective implementation of training models, an overview of the nature and validity of the available models is of the essence.

OBJECTIVE

To obtain an overview of training models and their validity by performing a qualitative systematic review of the literature.

EVIDENCE ACQUISITION

Studies were identified through searches of PubMed, the Cochrane Library, and Web of Science between January 1980 and April 2008 using two search strategies: "urology and (training or simulat or model)" and combinations of these terms with "prostate," "kidney," "bladder," or "ureter." Studies were included if they (1) described one or more training models, and/or (2) examined the validity of training models. Studies in undergraduate education and of training models for physical examination were excluded. Validation studies were scored according to Kirkpatrick and Oxford Centre for Evidence-Based Medicine (OCEBM) levels of evidence.

EVIDENCE SYNTHESIS

Forty-five articles (out of the initial list of 4753 retrieved articles, 0.9%) were included, describing 30 types of training models and 54 validation studies. The largest number of models has been described for ureterorenoscopy (nine types). Only three randomised controlled trials (RCTs), receiving a 1b OCEBM level of evidence score, were found. Studies investigating the impact of simulator training on performance in patients (criterion B validity) were scarce. The number of participants in experimental studies ranged from 7 to 136.

CONCLUSIONS

Due to growing interest in training models in urology, it is increasingly urgent to determine which of these models are most valuable for postgraduate training. Because the validation studies published so far are few in number, have low evidence levels, and are composed of only a few RCTs, it is important that more randomised controlled validation studies including larger numbers of participants are performed.

Surgical simulation: a urological perspective

PURPOSE

Surgical education is changing rapidly as several factors including budget constraints and medicolegal concerns limit opportunities for urological trainees. New methods of skills training such as low fidelity bench trainers and virtual reality simulators offer new avenues for surgical education. In addition, surgical simulation has the potential to allow practicing surgeons to develop new skills and maintain those they already possess. We provide a review of the background, current status and future directions of surgical simulators as they pertain to urology.

MATERIALS AND METHODS

We performed a literature review and an overview of surgical simulation in urology.

RESULTS

Surgical simulators are in various stages of development and validation. Several simulators have undergone extensive validation studies and are in use in surgical curricula. While virtual reality simulators offer the potential to more closely mimic reality and present entire operations, low fidelity simulators remain useful in skills training, particularly for novices and junior trainees. Surgical simulation remains in its infancy. However, the potential to shorten learning curves for difficult techniques and practice surgery without risk to patients continues to drive the development of increasingly more advanced and realistic models.

CONCLUSIONS

Surgical simulation is an exciting area of surgical education. The future is bright as advancements in computing and graphical capabilities offer new innovations in simulator technology. Simulators must continue to undergo rigorous validation studies to ensure that time spent by trainees on bench trainers and virtual reality simulators will translate into improved surgical skills in the operating room.

Review of trainers for transurethral resection of the prostate skills

Performance of transurethral resection of the prostate and bladder involves the ability to work in a small three-dimensional space while receiving two-dimensional visual feedback. The operation also demands adept psychomotor abilities, as one has to navigate the resectoscope and the loop continuously and simultaneously while managing the electrical current with the use of both hands and a foot pedal. The fact that the procedure is performed in a fluid environment and that the field often is obscured is an important factor to consider when creating a teaching tool, as the debris and blood can be disorienting to the resectionist in training. Historically, this training problem was addressed with sheer case volume, but the number of procedures performed during a residency has declined. Limbs and Things (Bristol, UK) created a synthetic "physical" disposable model of the prostate that allows the user to practice basic cutting skills. No usability or validation studies have been published on this model. Several virtual-reality (VR) TURP simulators have been described, with varying degrees of preliminary validation studies. The University of Washington VR TURP Trainer is licensed to Medical Education Technologies, Inc. (METI, Sarasota, FL). A force-feedback device has been integrated. The simulator has an integrated curriculum with subtask exercises, such as navigation, cutting, coagulation, and full resection modules. It logs motion and force data, as well as operative errors, grams of tissue resected, blood loss, irrigant volume, foot pedal use, and differential time spent with orientation, cutting, or coagulation. An AHRQ-funded multi-institutional predictive validity study is in progress, examining this simulator's ability to improve residents' performance in the operating room.

FACE, CONTENT AND CONSTRUCT VALIDITY OF THE UNIVERSITY OF WASHINGTON VIRTUAL REALITY TRANSURETHRAL PROSTATE RESECTION TRAINER

PURPOSE

We examined the face, content and construct validity of version 1.0 of the University of Washington transurethral prostate resection (TURP) trainer.

MATERIALS AND METHODS

Version 1.0 of a virtual reality based simulator for transurethral skills was developed at our laboratory by integrating TURP hardware with our virtual 3-dimensional anatomy, irrigation control, cutting, bleeding and haptics force feedback. A total of 72 board certified urologists and 19 novices completed a pre-task questionnaire, viewed an introductory training video and performed a pre-compiled 5-minute resection task. The simulator logged operative errors, gm resected, blood loss, irrigant volume, foot pedal use and differential time spent with orientation, cutting or coagulation. Trainees and experts evaluated the simulator on a modified likert scale. The 2-tailed Levene t test was used to compare means between experts and novices.

RESULTS

Overall version 1.0 content was between slightly and moderately acceptable. Experts spent less time with orientation (p < 0.0001), resected more total tissue (p < 0.0001), had more gm resected per cut (p = 0.002) and less blood loss per gm resected (p = 0.032), used less irrigant per gm resected (p = 0.02) and performed fewer errors (p < 0.0001) than novices.

CONCLUSIONS

We established the face, content and construct validity for version 1.0 of the University of Washington TURP trainer to simulate the skills necessary to perform TURP. A predictive validity study showing a translation of skills from the virtual environment to the operating room will complete the validation of this model.

Simulation of bleeding in endoscopic procedures using virtual reality

BACKGROUND AND PURPOSE

An image-based approach has been developed to represent bleeding in a simulator for transurethral resection of the prostate (TURP). Whereas previous groups attempted to simulate bleeding mathematically over tissue surfaces or in blood vessels, our approach focused on macroscopic visualization of bleeding in a fluid environment. The TURP is an ideal procedure for simulator-based training because of its importance as a skill to acquire as well as its long learning curve. The most challenging step in creating a realistic TURP simulator is simulated bleeding.

MATERIALS AND METHODS

We took an image-based approach in which we generated blood flow movies of bleeding vessels having different severity and position under variable fluid flow conditions and processed them to separate the blood flow from the background anatomy. We then organized the movies into a parametric database. During the running of the simulation, resection systematically triggers the playback of a blood flow movie (bleeding event). The movie is texture mapped onto a virtual surface that is positioned, oriented, morphed, composited, and looped into the virtual scene.

RESULTS AND CONCLUSION

The technique produced an accurate depiction of bleeding vessels one would encounter during a TURP. The image changes readily according to the fluid flow state.