453connected, as if the UPJ obstruction had already been excised. The model is then
placed within a box consisting of five hinged boards, which can be adjusted to
mimic the limited working space of the retroperitoneum. As would be done with
a standard box trainer, the box is then used with standard laparoscopic equip-
ment. The authors found in a cohort of five surgeons that operative time sig-
nificantly reduced after using the trainer (41.84 vs 25.04 min, p < 0.01) and the
surgeons rated themselves better on a general self- efficacy score (22.20 vs 27.60,
p < 0.01). The authors also compared complication rates of the surgeons in real
patient cases before and after simulation. Analyzing 15 patients prior to simula-
tion for an average of 6.6 months follow-up, one patient experienced a restenosis
and another patient experienced a prolonged urine leak. They then compared
this to a group of 15 additional patients, followed at an average of 7.4 months
after model simulation, and found there were no reported complications [ 54 ].
However, it is unclear if this study was powered to be able to detect significant
differences in complications.
Animal models are also available to simulate LPP training. Ramachandran et al.
were the first to describe the unique anatomy of the chicken esophagus to simulate
LPP by using the chicken crop and esophagus to simulate the renal pelvis and ure-
ter, respectively [ 55 ]. The crop of the chicken is a dilated segment of esophagus
proximal to the stomach that primarily functions in food storage. Ramachandran
et al. exposed the crop and esophagus of a dead chicken and then cleaned and filled
the crop/esophagus with water to simulate a dilated renal pelvis. An 8F feeding
tube was then passed down the esophagus into the crop, and the esophagus was
ligated with a silk suture. The model was then placed into a standard box trainer,
and a dismembered LPP was performed. Three urology residents initially studied
this model in their final year of study, with each resident doing four LPPs over the
period of a month. The study found that at the first attempt, only one of the three
residents could complete the task because of technical difficulties experienced dur-
ing laparoscopic suturing. However, after the fourth attempt, all the subjects could
complete a good quality LPP in a mean time of 67.7 min, with each attempt taking
less time and with better anastomosis suturing scores [ 55 ]. Jiang et al. then went on
to demonstrate construct validity for this model in a separate study of 15 partici-
pants divided into three groups based off of experience. Participants were studied
on the time to completion, as well as with a quality score on a scale of 1–10
assessed by a blinded evaluator (exact tissue sutured, equality of bite sizes, equal
stitch intervals, lack of tissue tear, and water-tight anastomosis). The study found
that the model was able to distinguish level of experience both by time to perform
the task (33.80 min for experts vs 55.20 min for limited experience group vs
92.60 min in no experience group; p < 0.001) and in regard to a quality score (9.0
vs 7.2 vs 4.0; p < 0.001) [ 56 ].
There is one model currently described that uses live animals for LPP. Fu et al.
were able to perform 60 LPPs (each side done three times) on ten anesthetized
Guangxi Bama minipigs (20–30 kgs) using their own specialized proposed method
[ 57 ]. Ten hours before surgery, the pigs fasted and underwent bowel preparation and
24 Simulation in Surgery