Transurethral Resection of the Prostate Skills A Potential Training Crisis

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Transurethral resection of the prostate remains the gold standard surgical procedure for successfully treating medically refractory lower-urinary tract symptoms of benign prostatic hyperplasia or benign enlargement of the prostate (50,51), a chronic and potentially

TURP is challenging to teach and iearn.

TURP is potentially dangerous.

Transurethral resection of the prostate outcomes vary widely in the community and are probably technically dependent.

A decade ago, residents performed 120 TURPs on average prior to graduating from a residency program. This number has declined in the last decade.

progressive condition that is symptomatic in approximately 5.6 million men in the United States alone.

The resection skills acquired during the performance of this procedure are also thought to translate to those used to resect benign and cancerous lesions in the bladder (TURBT) and in ablating posterior urethral valves in infants (TURPV). This set of skills remains a core skill set for a urologist in training (52).

Transurethral resection of the prostate is challenging to teach and learn. Performing this procedure involves the ability to work in a small three-dimensional space while receiving two-dimensional visual feedback requiring the operator to have or develop unique visual-spatial abilities. It also requires that the operator have adept psy-chomotor abilities, as one has to continuously and simultaneously navigate the scope and the loop while managing the electrical current with the use of both hands and a foot pedal. Additionally, the procedure is performed in a fluid environment and the field is often visually obscured by tissue and blood, which can be disorienting to the training resectionist.

Transurethral resection of the prostate is potentially dangerous. Within this small amount of space, there are also many potential anatomical hazards, where an error in judgment, visual-spatial or psychomotor skill could potentially result in devastating consequences such as total urinary incontinence, rectal injury, ureteral injury, dorsal vein injury with profuse blood loss, erectile dysfunction, and life-threatening levels of hyponatremia. Historically, such a small margin of error coupled with the "disconnect" that exists between the operators and the patient that inherently exists with all endo-scopic procedures has made training this skill set challenging.

Transurethral resection of the prostate outcomes vary widely in the community and are probably technically dependent.

Much like any procedural skill in medicine, when a urologist becomes board certified, the ability to perform technically challenging procedures such as transurethral resection of the prostate is not discriminated from the urologist's judgment and cognitive skills, which are measured via oral and written examinations. This fact as well as financial incentives has led many practicing urologists to pursue "alternative" or "minimally invasive" methods to deal with bladder outlet obstructive symptoms. While promising, and useful in many settings, none of these procedures has ever "outperformed" transurethral resection of the prostate in treating either the subjective symptoms of bladder outlet obstruction or objective measurements such as peak urinary flow rates and ability to empty one's bladder completely (51). In fact, depending on the series, transurethral resection of the prostate gives symptom relief anywhere from five to 20 years and the minimally invasive treatments follow-up data are only 3-5 years in evolution. Even within this period of time, 10% to 20% of patients undergoing an office bladder outlet reductive procedure go on to have a transurethral resection of the prostate anyway (51,53). The published morbidity of transurethral resection of the prostate is also quite variable. Average length of hospital stay ranges from 1.5 to 4 days, the incidence of urinary tract infections ranges from 4% to 20%, the reintervention rate (within 30 days after treatment) ranged from 0% to 14%, erectile dysfunction ranged from 0% to 21% and retrograde ejaculation ranged from 50% to 80% (53-61). Part of the discrepancy can be explained by different outcome measures, though many argue that this is due to a variable of surgical technique. Past studies have been unable to examine or quantify this, as we have lacked a standardized objective way of measuring transurethral resection of the prostate skills.

Historically, this training problem was addressed with shear case volume. A decade ago, residents performed 120 transurethral resection of the prostates on average prior to graduating from a residency program. This number has declined in the last decade (Fig. 12).

With the advance of medical management and less effective but lucrative "minimally invasive procedures," transurethral resection of the prostates are performed less frequently, but still remain the gold-standard therapy. The mean number of transurethral resection of the prostates a graduating resident had performed in 2002 has reached a plateau at 62 (ACGME). Without the benefits of a learning curve or objective data to reference, our group surveyed 72 board-certified urologists at the American Urological Association 2002 meeting and the perceived mean number of transurethral resection of the prostates they felt was necessary before entering independent practice was 66.8; a number well above the mean and encompassing a majority of the graduating residents in the United States (31).

Given all the mentioned issues, simulation model training for transurethral resection of the prostate has been pursued. The first reported virtual reality transurethral resection of the prostate simulator was described by Lardennois et al. in 1990 (62) after having seen a colonoscopy simulator. Since 1999, Kumar et al. have

FIGURE 12 ■ ACGME data on the mean number of TURPs done by U.S. urology residents. Source: From Ref. 30.

National Average Number of TURPS performed by residents

1DO BO SO 40 20

Source: ACGMF.

1990 199! 1994 l»9t I99H

worked on a TUR simulator, which uses an optical tracking device and a hybrid/computer-generated and physical prostate model. The loop is tracked with a potentiometer and the scope is tracked in space. It was constructed as a virtual three-dimensional training aid to eventually be used in the operating room, but lacked features such as bleeding. Two urologists evaluated the content and felt that a poor frame refresh rate, a lack of bleeding and model movement and permanent deformation of the model as well as deformation secondary to absorbing fluid all contributed to made the trainer inaccurate in vitro. Validation studies are currently lacking but in vivo studies are in progress (63,64). Ballaro et al. (65) also created a virtual reality transurethral resection of the prostate simulator, but it lacked real-time interactivity and tactile feedback. Manyak et al. (66) also describe a simulator for lower urinary tract procedures, which adds haptics force feedback. No validation studies have been described in the literature for any of these trainers.

Sweet et al. began development of the UW virtual reality transurethral resection of the prostate trainer in 2000. Using Alias®, a virtual polygonal model of the urethra, prostate, bladder, and the loop was created de novo. Instrumentation and interaction was accomplished by securing two Polhemus tracking devices to an iglesias and a camera shell provided by ACMI®. A Bovie® foot pedal was used, and the electrical signal is transmitted to an SGI Octane® graphics computer through a TNG-3® interface box. A physical model of the penis and pelvis was created in collaboration with Simulab Corp®. using prosthetic materials. Computer graphics animation in Alias was used to recreate noninteractive portions of the simulation such as urine efflux and chip movement. Upon collision between the loop and the model, cutting was accomplished by "pushing" the anatomy of the model to accommodate the intersection between the loop and the tissue. Texture maps of prostatic urothelium, bladder urothelium, resection bed, and fat were obtained using digital footage from actual transurethral resection of the prostate procedures. Recognizing that dealing with hemostasis was a critical skill set to learn during transurethral resection of the prostate, an in vitro model for bleeding during transurethral resection of the prostate and a bleeding movie library taken from an in vitro model of the lower genitourinary tract under controlled fluid flow conditions were created. Fluid flow detection by the use of potentiometers attached to the stopcocks that trigger the changing of the blood flow movies is also employed. The result was a realistic interactive simulation of blood flow under fluid conditions. A force feedback device was then integrated using a custom Mantis device); didactics and a graphics user interface have been put on the front end and subtask training modules have been added, which train orientation, cutting, and coagulation skills independently. The simulator can log motion and force data as well as operative errors, grams resected, blood loss, irrigant volume, foot pedal use, and differential time spent with orientation, cutting, or coagulation. The result is a complete transurethral resection of the prostate simulator that can provide objective feedback to the user. Version 1.0 was validated by 72 board-certified urologists and 19 novices at the AUA 2002 and face, content, and construct validity of the simulator was established (31). Based on these data, the simulator has been upgraded and the authors endorsed the simulator for training but cautioned its use for assessment and accreditation, though the simulator was also able to discriminate differences of skill within groups (unpublished data). Plans are underway to perform a multi-institutional predictive validity study examining the simulator's ability to improve performance in jMimic Technologies, Seattle, WA.

the operating room with residents and the ability of subtask training to improve performance in medical students. If strong predictive validity is established with this multi-institutional design, use for assessment accreditation could be considered. It is being distributed as a beta-prototype to select institutions and ideally it would be expanded to other transurethral procedures as well.

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