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Practical Urology: EssEntial PrinciPlEs and PracticE

however, may limit the degree of scope move-

development of an adequate skill set for the

ment, resulting in suboptimal access to calyces

medical students to perform basic ureteroscopy.

not favorably aligned to the percutaneous tract.

The author concluded that initial training on

For this reason, a flexible cystoscope (described

the simulators might improve a novice’s or resi-

above) serving as a flexible nephroscope may be

dent’s early clinical experience. The improved

utilized, allowing the endoscopist to inspect the

familiarity with the instrumentation allowed

entire collecting system without resulting in the

reduced procedure time and improved compe-

same physical torque to the kidney.7 The use of

tence. Virtual reality simulators, both low and

flexible nephroscopy during the primary PCNL

high fidelity, have the potential to play an impor-

procedure increases the stone-free rate and

tant role in urologic training, perhaps enhance

decreases the need for additional access tracts.8

the historical teacher–apprentice model,and may

eventually be incorporated into assessment of

procedural competence similar to their use in the

In the modern health care environment a variety

aviation industry.

of factors including the potential for improved

Lasers

teaching and patient safety combined with

decreasing declining reimbursement, decreased

available operative time, decreased resident

Lasers have occupied an increasing role in the

hours and case numbers may increase the use of

treatment of urologic disease. The term

simulators in resident training. Some authors

“LASER”(Light Amplification by the Stimulated

advocate that simulation systems should be a

Emission of Radiation) was initially proposed

mandatory part of residency training,to include

by Albert Einstein in 1917. Forty-three years

aptitude skill testing before being able to

after Einstein’s first theories, Maiman intro-

on humans.9

duced the first visible light laser with synthetic

A potential benefit to the virtual reality simula-

ruby crystals and silver-coated ends surrounded

tor is that the trainee can acquire adequate skills

by a flash tube to produce light energy.14 This

in a low-risk environment. “High fidelity” vir-

marked the beginning of laser use and a bridge

tual reality trainers consists of a monitor, work-

between quantum physics and clinical medi-

station with an integrated mechatronic unit

cine. The earliest use of laser technology in clin-

providing force feedback, and a personalized

ical urology started in 1966 with Parsons studies

computer. Endourologic procedures are well

with a ruby laser in a pulsed mode on canine

replicated in simulator training because of the

bladders.14 In 1968, Mulvany fragmented uri-

ability to provide realistic sensations of pressure

nary calculi using a similar laser.14 Currently,

and force feedback.10 The software contains pro-

lasers are widely used and often the primary

cedures including resection of bladder tumors,

tool for the treatment of urolithiasis,endoscopic

laser lithotripsy, percutaneous access place-

organ-preserving tumor ablation, ureteral and

urethral strictures, and benign prostatic

Although the use of such simulators is rela-

hyperplasia.

tively new, several small studies have evaluated

Briefly, Einstein’s concept of stimulated

the efficacy of the simulator training and found

emission is based on two principles of physics.

potential benefit.11,12 One study found that it

The first is that light travels as photons or pack-

was possible to tell the difference between

ets of energy. The second is that atoms and

“expert” and “novice” endoscopists by evaluat-

molecules exist in a low energy state. Laser

ing each cystoscopic task and time to complete

energy is produced when an atom becomes

the task. In another study at University of

excited by an external energy source, such as

California, Irvine, medical students were taught

by electricity, heat, or light energy, causing

ureteroscopic skills on either an ureteroscopy

excited electrons to release excess energy in the

training model (TMU) (Limbs & Things) or the

form of photons or light energy. The typical

URO Mentor (Simbionix, Israel).13 After

energy source in a laser is electric or flashlamp

completing the training course, their newly

driven, and produces excited atoms as the basis

acquired skills were assessed in an animal model

for the laser medium. The photons emitted

provided for

spontaneously from the excited molecules