REFERENCES

1. Kollmorgen, T. A., Malek, R. S. and Barrett, D. M.: Laser pros-tatectomy: two and a half years’ experience with aggressivemultifocal therapy. Urology, 48: 217, 1996

2. Cowles, R. S., Kabalin, J. N., Childs, S. et al: A prospectiverandomized comparison of transurethral resection to visuallaser ablation of the prostate for the treatment of benignprostatic hyperplasia. Urology, 46: 155, 1995

3. Kuntzman, R. S., Malek, R. S., Barrett, D. M. et al: High-power(60-watt) potassium-titanyl-phosphate laser vaporizationprostatectomy in living canines and in human and caninecadavers. Urology, 49: 703, 1997

4. Kuntzman, R. S., Malek, R. S., Barrett, D. M. et al: Potassium-titanyl-phosphate laser vaporization of the prostate: a compar-ative functional and pathologic study in canines. Urology, 48:575, 1996

5. Malek, R. S., Barrett, D. M. and Kuntzman, R. S.: High-powerpotassium-titanyl-phosphate (KTP/532) laser vaporizationprostatectomy: 24 hours later. Urology, 51: 254, 1998

6. Stein, B. S.: Neodymium:yttrium-aluminum-garnet laser pros-tatectomy. Mayo Clin Proc, 73: 787, 1998

7. Kabalin, J. N., Bite, G. and Doll, S.: Neodymium:YAG lasercoagulation prostatectomy: 3 years of experience with 227patients. J Urol, 155: 181, 1996

8. Bruskewitz, R., Issa, M. M., Roehrborn, C. G. et al: A prospec-tive, randomized 1-year clinical trial comparing transurethralneedle ablation to transurethral resection of the prostate forthe treatment of symptomatic benign prostatic hyperplasia.J Urol, 159: 1588, 1998

9. Francisca, E. A. E., d’Ancona, F. C. H., Meuleman, E. J. H. et al:Sexual function following high energy microwave thermother-apy: results of a randomized controlled study comparing trans-urethral microwave thermotherapy to transurethral prostaticresection. J Urol, 161: 486, 1999

10. Gilling, P. J., Mackey, M., Cresswell, M. et al: Holmium laserversus transurethral resection of the prostate: a randomizedprospective trial with 1-year followup. J Urol, 162: 1640, 1999

EDITORIAL COMMENTS

Laser prostatectomies of all types have been advanced as an al-ternative to standard transurethral resection of the prostate forreasons of economy, efficacy and supposedly decreased sexual dys-function. In reality, long-term results have been less than over-whelming. In the KTP laser prostatectomy series originally reporteda laser calibrated to 38 W. was used but in reality rarely delivered

more than 20 W. of power. The procedure of vaporization waslengthy, tedious and often erratically performed.

The authors detail a major breakthrough with a KTP laser thatdelivers 60 W. to a side firing fiber. Depth of penetration is improvedproducing a decreased operative lasering time. The obliteration ofadenoma was possible to the limits of the prostatic capsule. Cathetertime and postoperative symptoms scores compared favorably to re-cent transurethral resection series. These results can be duplicatedby other investigators. The KTP 60 W. laser prostatectomy may behonestly compared favorably to transurethral resection of the pros-tate in all respects.

Terrence R. MalloyMalloy-Carpiniello AssociatesPhiladelphia, Pennsylvania

The results of laser prostatectomy are directly dependent on anumber of factors, including wavelength, power, duration and tech-nique. Some of the tissue characteristics that have made prostatec-tomy with a neodymium:YAG laser appealing, that is the excellentcoagulation and hemostasis, also limit the cutting effect and abilityto achieve immediate tissue removal. The holmium:YAG wavelengthis absorbed more strongly by water and incises tissue better but isless hemostatic. The more tissue vaporization and cutting effect areachieved, the less tissue coagulation and hemostasis occur.

The KTP laser used by the authors has characteristics of tissueabsorption somewhat intermediate between a neodymium:YAG andholmium:YAG laser. The 532 nm. wavelength is strongly absorbedby hemoglobin but less so by water. The characteristics are some-what similar to an argon laser. The high power prototype KTP laserthey used was able to achieve tissue vaporization which providedgood immediate voiding outcomes.

If the goal of prostatectomy is to remove or eradicate obstructivetissue, multiple laser wavelength and techniques can accomplishthis goal. Virtually all have been reported as “patient and user-friendly.” It becomes difficult to make direct comparisons based uponsmall phase II studies. However, techniques that provide immediatetissue vaporization, such as the one described by the authors, appearto result in better outcomes than those that rely on tissue resorptionand sloughing.

Joseph A. Smith, Jr.Department of Urologic SurgeryVanderbilt University Medical CenterNashville, Tennessee

POTASSIUM-TITANYL-PHOSPHATE LASER PROSTATECTOMY 1733