MOSES technology was developed by Lumenis Ltd to maximize the lithotripsy potential of
high powered lasers. Typically, a holmium laser unit is used to treat kidney a ureteral
stones that are too large to remove en block. Laser lithotripsy allows for a large stone
to be partitioned into smaller fragments that can be removed with an endoscopic basket
device. Holmium technology has existed for more than 20 years, however, low total power
(40 watt) and minimal modulations (Joules and Hertz) of the laser energy by the laser
units limited the capacity to improve lithotripsy efficiency.
With the advent of high power (120 watt) lasers with 4 laser cores and developments in
software to modulate the laser energy, many more options have emerged for laser
lithotripsy of kidney and ureteral stones. At Indiana University Health Physicians
Urology, the laser units used for nephrolithotripsy are engineered and produced by
Lumenis Ltd. These units are fitted with MOSES technology. Standard laser lithotripsy or
MOSES laser lithotripsy can be performed using the same unit and during the same case by
simple turning MOSES on or off on the laser touch screen (image 1). MOSES is propriety
technology that is software based modulation of the laser energy delivered from the
holmium::yag laser source. The software changes the pulsed laser to have two peaks of
energy - one to displace the water in front of the stone and the second to deliver the
laser energy to the stone. Holmium laser energy dissipates quickly in water, so the
displacement of water in front of the stone means more energy is delivered to the stone.
With more energy delivery, stone fragmentation is expected to occur more rapidly.
When treating kidney or ureteral stones, there are two distinct surgical approaches. One
technique is to use laser lithotripsy to break a stone into tiny pieces called dusting.
Dusting technique attempts to turn a stone into a slurry of 2mm or less stone fragments
that the patient can pass spontaneously. There are some urologist who promote the use of
MOSES technology to improve the efficiency of the dusting technique and reduce operative
time. Another approach to endoscopic stone surgery is to laser the stone into fragments
to remove with a basket. There is far less laser energy used in this process, however,
hard stones and larger stones can take time to fragment. Based on the dusting
ureteroscopy data, MOSES technology could still improve fragmentation efficiency and
reduce overall operative time.
This is a blinded study. The research coordinator will present to the OR prior to the
surgeon to meet with OR staff. At this time, the coordinator will inform the OR staff
which group the participant has been randomly assigned. OR staff will be educated to set
the laser as instructed by the surgeon but not share whether the MOSES laser lithotripsy
is being used. Surgeons will not be aware of the group assignment. The surgeons are only
able to adjust the laser energy settings between 0.4-1.0 joules and 4-15 hertz. To
control for stone fragment size, surgeons will have to use an 13 french ureteral access
sheath independent of ureteral diameter. The MOSES setting is turned on with a touch pad
attached to the laser unit. Once the surgeon is ready to laser fragment the stone, the
laser will be activated and with the surgeon provided laser energy settings. The laser
technician/nurse will follow randomization and add or remove the MOSES option. The
surgeons will not be informed if using standard laser or MOSES augmented laser
technology. At the conclusion of laser fragmentation, stone basket extraction will occur
and once all fragments are removed, the patient will have a ureteral stent placed,
awoken, extubated and transferred to the post anesthesia recovery unit. Objective data
about laser settings, utilization time and total energy will be obtained at the
conclusion of the case. Additionally, the circulating team will record the total OR time.
Other variables of interest include blood loss, blood transfusion requirements and
complications (utilizing Clavien-Dindo classification) with an expected rate of
approximately 1-2%. Subjective grading of stone movement during laser fragmentation as
well as stone migration will be recorded.
In addition to the intraoperative variables mentioned above, clinical information
including stone size, location, and stone analysis will be recorded.