Key features to consider
In BPH laser surgery, there are two choices of target chromophore; water and hemoglobin. Thulium and holmium lasers rely on water for their effect whereas KTP lasers rely on hemoglobin. Having water as the primary chromophore means that the laser will deliver predicable results regardless of the tissue vascularity. Having water as the primary chromophore also means that the laser energy will not travel a significant distance from the probe tip. This feature helps avoid accidental delivery of laser energy to tissues behind the area being treated.
Side-firing or forward firing fibers
KTP and holmium lasers require the use of single use side-firing fibers. These fibers typically cost between $700 and $900. If the procedure is long or if the fiber accidently comes into contact with tissue too much, the fiber can burn-out meaning a second fiber may be necessary.
Compare this with the reusable forward firing fiber typically used with thulium lasers. These fibers are not only more durable and easier to use, they can be reused multiple times.
Side firing fibers also increase the risk of scope damage if the fiber is accidently activated without being extended from the scope a minimum distance.
Ability to both vaporize and vapo-resect
A recent study published in Urology International showed that 11.4% of men not suspected of having prostate cancer, were later diagnosed with cancer based on analysis of their TURP specimens. This clearly demonstrates the advantage of using a laser that is capable of providing tissue specimens for inspection. KTP lasers do not provide this advantage. Only holmium and thulium lasers provide this important advantage. Holmium lasers, however, do not vaporize as efficiently as thulium lasers and therefore either take much longer to perform a procedure or require use of a mechanical morcellator to remove the larger tissue fragments.
One of the important advantages of laser surgery for BPH is the precision that it affords. Lasers, particularly; contact lasers, allow the surgeon to precisely control the delivery of therapy. He can remove the obstructive tissue with high precision, however, only if he can clearly see what he is doing and only if he can clearly evaluate the structure of the underlying tissue to know when he has reached the transverse fibers, fat layers, etc. Compared with the holmium laser, the thulium laser provides a significantly clearer surgical field. Holmium lasers deliver extremely high-power pulses that create large pulsating steam bubbles at the end of the probe that tear away at tissue creating tiny fragments and a ragged defect. The mechanical trauma of the pulsating steam bubble further breaks small blood vessels which gives rise to bleeding. These factors result in an often cloudy surgical field and a treatment surface that is hard to see.
In contrast the thulium laser leaves a very clean treatment surface that allows the surgeon to clearly see the tissue he is treating.
Urol Int. 2009;83(2):171-4. Epub 2009 Sep 10.