469The PelvicVision TURP simulator is another VR TURP simulator that has shown
construct validity in two small studies. This model consists of a modified resecto-
scope attached to a robotic arm, foot pedals, and a standard desktop computer [ 115 ].
The simulator gives haptic feedback as well as real-time tracking of variables such
as resectoscope movements, blood loss, resection volumes, flow of irrigation, and
operative errors, such as bladder perforation, resection of sphincter, and perforation
of prostatic capsule. Källström et al. proved construct and content validity in a small
study with this model that involved students. These students were able to demon-
strate a positive learning curve and improving self-assessments in which they found
the procedure to be easier with an increasing numbers of simulations [ 115 ].
Photoselective Vaporization of the Prostate (PVP)
Introduced in 1998, the GreenLight™ (American Medical Systems, Inc.
Minnetonka, MN) laser photoselective vaporization of the prostate (PVP) has
proven to be an effective treatment of bladder outlet obstruction secondary to BPH
with significantly less morbidity than traditional TURPs [ 116 – 118 ]. GreenLight
PVP uses a potassium-titanyl-phosphate (KTP) laser, of which it has a wavelength
that is selectively absorbed by hemoglobin. Thus, tissue containing hemoglobin is
preferentially vaporized with near instantaneous hemostasis [ 119 ]. AMS created a
model, the GreenLight Simulator (GL-SIM), due to the popularity of GreenLight
PVP. This simulator has shown both face and content validity [ 120 ]. The GL-SIM
consists of a camera, scope, laser fiber, and foot pedal which are all pre-attached to
a module. A standard laptop is used to run its VR software and display the video
output. The system comes pre-loaded with five task-training modules, including
anatomy identification, sweep speed, tissue-fiber distance, power settings, and
bleeding coagulation. It also is pre-loaded with six full operative cases consisting
of increasingly larger and more challenging prostates. Herlemann et al. have shown
the GL-SIM to have face, construct, and content validity. Face and content validity
was later confirmed by Aydin et al. [ 121 ]. They showed in their study that construct
validity was demonstrated in two of the five training modules, as well as in opera-
tive time, errors made, and instrument cost [ 120 ]. Interestingly, Herlemann et al.
found improved simulation outcomes in those that were able to play a musical
instrument [ 121 ].
Holmium Laser Enucleation of the Prostate (HoLEP)
Similarly to PVP, Holmium Laser Enucleation of the Prostate (HoLEP) embodies
an emerging alternative to the standard TURP. HoLEP uses a holmium:yttrium-
aluminum- garnet (Ho:YAG) laser to enucleate entire lobes of the prostate via emis-
sion of pulsed 2140 nm energy [ 122 ]. There are some urologists stating that HoLEP
has become the new “gold standard” for surgical management of BPH based on its
efficacy and low morbidity [ 123 ]. However, due to its significantly different tech-
nique when compared to TURP, HoLEP has a very steep learning curve—much
longer than that of a standard TURP [ 124 ]. This unfortunately is a major disadvan-
tage of HoLEP and a reason that many in the urological community have not adopted
24 Simulation in Surgery