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Editorial: Laser Prostatectomy—What We Have Accomplished and Future Directions
~22-5347/95/1546-2093$03.00/0
Vol. 164.2093-2095. Deoember 1995 Printed in U.SA
JOURNAL OF UROLOGY
Capfight 0 1995 by AMERICANU R O ~ I CASS~CUTION, AL hc.
EDITORIAL: LASER PROSTATECTOMY--WHAT WE HAVE ACCOMPLISHED AND FUTURE DIRECTIONS Within the last, few short years, neodymium:YAG laser While these represent signiscant accomplishmentsachieved prostatectomy has successfully joined the surgical ap- during a relatively short interval for a new surgical technique, proaches to the management of benign and malignant pros- and more than j e the increasing acceptance of laser prostatic obstruction of the bladder outlet. From early experimen- tatectomy in our practice, the current operative approach to tation with simple, end-firing, bare fibers14 to the important neodymium:YAG laser treatment of the prostate is not without experiences gained during development of the transurethral disadvantagea. The major drawback of current approaches in ultrasound guided laser induced prostatectomy (TULIP)de- clinical practice is the lack of immediacy of effects on voiding vice specifically for laser prostatectomy,4-6 the first of the symptoms. Whereas most patients undergoing standard transfree beam, side-firing flexible fiber delivery systems uretbral electrocauteryresection of the prostate require urinary emerged7-13 and gained acceptance as a practical transure- catheterization for 1to 3 days, and most can also expect drathral endoscopic instrument to deliver ne0dymium:YAG light matic improvement in voiding within 1week ptoperatively, energy to the prostate. Since 1992,a multitude of side-firing the physiology of ne0dymium:YAG laser ablation and coagulaneodymium:YAG laser fibers of variable configuration have tion of the prostate is much Werent. While some tissue may be been introduced, all primarily intended for use in prostatic removed acutely, the predominant effect of the neodymium: surgery. More recently, the accessibility of these delivery YAG laser in the human prostate-and the same effect that 80 systems has been combined with review and recognition of drastically limits acute operative morbidity-is tissue coagulalaser prostatectomy by the United States Health Care Fi- tion.% Thus, all patients can expect significant prostatic edema nancing Administration and American Medical Association postoperatively and ongoing loss of transition zone tissue for in conjunction with the American Urological Association to many weeks thereafter. Clinically,although many patients will allow the creation of appropriate codes in the Physicians' tolerate 1to 3 days of catheterization as mprted by Narayan et Current Procedural Terminology, thus facilitating reim- al (page 20831, most men are more wmfortable and better bursement for this operation in the United States and estab- served by 5 to 10 days with a urinary catheter (most practitiolishing laser prostatectomy in everyday urological practice. ners currently arbitrarily leave a urethral catheter in place for The advantages of laser prostatectomy are 3-fold. 1) It is an 1 week following ne0dymium:YAG laser prostatetomy). Neiefficacioustreatment for symptomatic bladder outlet obstruc- ther steroidal nor nonstemidal anti-inflammatory drugs have tion due to benign prostatic hyperplasia or prostatic carci- proved able to prevent this edema or decrease the need for noma. In randomized comparisons with transurethral elec- pastoperative cathetektion in clinical practice. Even after trwautery resection of the prostate, neodymium:YAG laser this acute phase of tissue edema subsides, most of the transition prostatectomy has consistently provided patients with simi- zone tissue loss has yet to acmr and patients will experience lar symptomatic impro~ement.1"'~With more recently avail- only gradual resolution of voiding symptoms that may continue able long-term followup of patients undergoing laser prosta- for 6 to 12 weeks or longer postoperatively. Costello et al implitectomy, this operation appears to offer durability of benefits cated ischemic as well as direct the& iqjury to the pmtatic and retreatment rates that are also similar to those of trans- transition zone to account for this ongoing, prolonged tissue urethral electrocautery resection of the prostate.18.192)Laser loss.% A uniquely innovative approach to this problem is the prostatectomy has proved to be remarkably safe, demonstrat- use of bicdegradable prostatic stents, as reported by Talja et al ing a significant decrease in short-term morbidity compared (page 2089), to allow for unimpeded urination immediately to transurethral electrocautery resection of the prostate in after ne0dymium:YAG laser prostatectomy. While such &nts these same studies.1"17 Coagulation of the prostatic paren- are still not perfected, and probably will have a desired minimal chyma by the neodymium:YAG wavelength, sealing blood functional life span of at least 12 weeks rather thanthe current vessels and preventing absorption of irrigation fluid as well 3 to 4 weeks, they promise an easy and mhimally morbid as bleeding, accounts for much of this morbidity abatement solution to post-prostatedomy voiding problems, that is an esand significantly diminishes the overall physiological stress sentially imperceptible internal catheter that requires no mainproduced by laser prostatectomy compared to transurethral tenance and that eventually removes itself after serving its electrocautery resection of the prostate. In prior studies this Purpose. A key factor limiting the wider dissemination of laser proshas been documented crudely by the lack of effects on hemoglobin or hematwrit and serum electrolyte levels9~12~13 but it tatectomy is the relative lack of experience and comfort with has now been definitively and elegantly demonstrated by a lasers for many urological practitioners, compounded by the quantitative breath ethanol techniaue in the article by confuaing multitude of laser fibers, differing laser beam conCummings et al (page 2080)in this issue of the Journal. The figuratio-ns and operative techniques proposed. Unlike elecsafety and minimal physiological stress produced by laser troresectoscopes. which are essentially interchangeable, exprostatectomy have allowed the routine surgical treatment of isting side-firing laser fibers emit beams that vary widely in Patients with severe underlying medical diseases and even angle of emission, divergence and energy density.26 These those systemically anticoagulated-groups previously of- laser beam differences demand significant variations in o p fered prostate surgery with some trepidation.20-22 Further- erative techniques that are fiber-dependent and not necesFore, laser prostatectomy appears much less likely to cause sarily interchangeable.27-29 Lacking knowledge of laser physIncontinence, impotence or urethral stricture than transure- ics and laser-tissue interactions, whether generally or for a 3) Largely specific delivery device configuration, and the matching of an thral electrocautery resection of the pro~tate.'~ because of the hemostasis and lack of physiological stress inappropriate operative technique with a given laser fiber Produced by neodymium:YAG laser prostatectomy, patients will tend to produce less than maximal voiding outcomes in Can be treated routinely on an outpatient basis, which com- practice. With a narrow, high energy density laser beam, spot bined with lower complication rates appears to offer a genu- coagulation of the prostate may produce less significant reine cost benefit for laser prostatectomy compared to trans- sults and more complications than using a slow painting or dragging technique, such as that originated with the TULIP Wethral electrocautery resection of the prostate.23 2093
2094
LASERPROSTATECTOMY
2. Kandel, L. B., Harrison, L. H.,McCullough, D. L., Boyce, W. H., Woodruff, R. P. and Dyer, R. B.: Transurethral laser prostatectomy: creation of a technique for using the neodymium: yttrium & ~ ~ ~ I Ugarnet I D WAG) laser in the canine model. J. Urol., part 2,13fl: l l O A , abstract 27, 1986. 3. Bloiso, G., Warner, R. and Cohen, M.: Treatment of urethral diseases with neodymium:YAG laser. Urology, 3 2 106,1988. 4. Assirnos, D. G., McCullough, D. L., Woodruff, R. D.,Harrison, Canine transurethral laserL. H., Hart, L. J. and Li,W.J.: induced prostateetomy. J. Endourol., 5: 145, 1991. 5. h t h , R. A. and Aretz, H. T.: Transurethral ultrasound-guided laser induced prostatectomy (TULIP procedure): a canine prostate feasibility study. J. Urol., 144% 1128, 1991. 6. McCullough, D. L., Roth, R. A, Babayan, R. K, Gordon, J. O., Reese, J, H.,Crawford, E. D., Fuselier, H. A., Smith, J. A., Murchison, R. J. and Kaye, K W.: Transurethral ultrasoundguided laser-induced prostatectomy: National Human Cooperative Study results. J. Urol., 1M): 1607,1993. 7. Johnson, D. E., Price, R. E. and Cromeens, D. M.: Pathologic changes occurring in the prostate following transurethral laser prostatectomy. Lasers Surg. Med., 1 2 254, 1992. 8. Costello, A. J., Bowsher, W. G., Bolton, D. M., Braslis, K. G. and Burt, J.: Laser ablation of the prostate in patients with benign prostatic hypertrophy. Brit. J. Urol., 6% 603, 1992. 9. Kabalin, J. N.: Laser prostatectomy performed with a right angle firing neodymium:YAG laser fiber at 40 watts power setting. J. Urol., 160:95, 1993. 10. Norris, J. P.,N o d , D. M., Lee, R. D. and Rubenstein, M. A: Visual laser ablation of the prostate: clinical experience in 108 patients. J. Urol., 160: 1612,1993. 11. Leach, G. E., Sirls, L., Ganabathi, K., Roskamp, D. and Dmochowski, R.: Outpatient visual laser-assisted prostatectomy under local anesthesia. Urology, 43: 149, 1994. 12. Kabalin, J. N., Gill, H. S. and Bite, G.: Laser prostatectomy performed with a right-angle firing ne0dymium:YAG laser fiber at 60 watts power setting. J. Urol., 153: 1502, 1995. 13. Cowles, R. S.,111, Kabalin, J. N., Childs, S., Lepor, H., Dixon, C., Stein, B. and Zabbo, A: A prospective randomized comparison of transurethral resection to visual laser ablation of the prostate for the treatment of benign prostatic hyperplasia. Urology, 44% 155, 1995. 14. Kabalin, J. N., Gill, H. S., Bite, G. and Wolfe, V.: Comparative study of laser versus electrocautery prostatic resection: 18month followup with complex urodynamic assessment. J. Urol., 15% 94, 1995. 15. Schulze, H., Martin, W., Hoch, P. and Senge, T.: TULIP vs. m.a prospective, randomized study. J. Urol., part 2, 151: 228A, abstract 3, 1994. 16. Costello, A. J. and Crowe, H. R.: A single institution experience of reflecting laser fibre prostatectomy over four years. J. Urol., part 2, 151: 229A, abstract 6, 1994. 17. Won, C., Machi, G., Theme, C., Olejniczak, G. and Lepor, H.: A prospective, double-blind, randomized study comparing the safety, efficacy and cost of laser ablation of the prostate and transurethral prostatectomy for the treatment of BPH. J. Urol., part 2, 151: 229A, abstract 7, 1994. 18. Costello, A. J. and Shaffer, B. S.: Laser ablation of benign prostatic hypertrophy (BPH): two and a half year experience with right angle delivery systems. J. Urol., part 2, 1 4 9 214A, abstract 3, 1993. 19. Kabalin, J. N., Bite, G. and Doll, S.: Neodymium:YAG laser coagulation prostatectomy: 3-year experience in 227 patients. J. Urol., in press. 20. Kabalin, J. N. and Gill, H.S.: Urolase laser prostatectomy in patients on warfarin anticoagulation: a safe treatment alternative for bladder outlet obstruction. Urology, 42: 738, 1993. 21. Miller, J., Becker, H. C., Ludwig, M., Schiefer, H.-G., Fischer, C. John N . Kabalin and Weidner, W.: Visual laser ablation of the prostate (WAF') Department of Urology in high risk patients-analysis of results and perioperative Stanford University School of Medicine morbidity. J. Urol., part 2, 153: 414A, abstract 741, 1995. 22. Kingston, T. E., Nonnenmacher, A. K, Crowe, H., Costello, A. J. Stanford, California and Street, A.: Further evaluation of transurethral laser ablation of the prostate in patients treated with anticoagulant REFERENCES therapy. Aust. New Zeal. J. Surg., 65: 40, 1995. 1. Shanberg, A. M., Tansey, L. A. and Baghdassarian, R.: The use 23. Kabalin, J. N. and Butler, E. D.: Costs of minimally invasive of the neodymium YAG laser in prostatectomy.J. Urol., part 2, laser surgery compared with transurethral electrocautery re133: 196A. abstract 331, 1985. section of the prostate. West. J. Med., 1 6 2 426, 1995.
procedure and later popularized for narrow divergence, free beam ndymium:YAG fibers.w-30 Using a fiber that emits a widely divergent, low energy density neodymium:YAG beam, spot coagulation techniques have proved optimal, while dragging techniques are relatively ineffective.27-29 A common denominator emerging for all successful operative techniques with the ne0dymium:YAG laser is the use of large amounts of ne0dymium:YAG laser energy to maximize tissue ablation, and thereby voiding outcomes. While Shanberg et al recommended energy doses of at least 1,000 JJgm. prostate tissue,31 we and many others now routinely deliver 1,500to 2,000 JJgm. or more of neodymium:YAG energy.19 Narayan et al effectively demonstrate improved results when total laser energy delivery to the prostate is more than quadrupled from a mean of 31 kJ. to nearly 130 kJ.-averaging significantly greater than 2,000 J./gm. tissue in the latter group. For the future, potential solutions to many or all of the present disadvantages of laser prostatectomy would be offered by the ability to use laser energy to vaporize obstructing prostate tissue acutely. If the low morbidity associated with neodymium:YAG laser coagulation of the prostate can be maintained, such an approach might have the dual potential of producing more immediate symptomatic improvement, thus minimizing catheterization and simplifying postoperative management, and allowing the operating surgeon to see the prostatectomy defect at operation, thus greatly simplifying intraoperative assessment of tissue treatment (in other words, "what you see is what you get") and eliminating much or all of the need for an in-depth understanding of laser physics. However, most vaporization approaches to date possess distinct disadvantages as well. Simply turning the power settings on the neodymium:YAG laser to 80 to 100 watts will produce limited tissue vaporization but the primary effect remains coagulation.= In addition, high power settings may actually limit the depth of tissue coagulation and, thus, total tissue loss during the long term,and they may also be associated with greater incidences of prostatic perforation or incontinence.m.29 The KTP laser wavelength offers little benefit over the neodymium:YAG wavelength in this application. Ne0dymium:YAG contact laser technology can effectively vaporize tissue and is more hemostatic than electrocautery. However, contact devices are less hemostatic than free beam ne0dymium:YAG tissue coagulation, tissue removal is relatively slow and contact laser prostatectomy is generally believed to be suitable only for smaller glands. Recently, use of the ho1mium:YAG laser wavelength for vaporization and resection of the prostate has proved to be much more efficient while maintaining excellent hemostasis with lack of fluid absorption.32 The minimal morbidity and immediate efficacy (overnight catheterization and transurethral electroresection-like resumption of voiding) observed following ho1mium:YAG laser vaporizationhesection in initial treatment groups should prove to be a significant advance in laser prostatectomy. Laser prostatectomy still represents a young science. The future promises further advances, and greater knowledge and understanding of this technology. With our growing experience, I believe the practitioner will witness ongoing simplification and improved ease of application of laser operative approaches in the future. Moreover, this future is probably not too distant.
LASERPROSTATECTOMY 24. Kabalin, J. N., Gong, M., Issa, M. M. and Sellers, R.: Insight into mechanism of neodymium:yttrium-aluminum-garnet laser
prostatectomy utilizing the high-power contact-free beam technique. Urology, 45: 421, 1995. 25. Costello, A. J., Bolton, D. M., Ellis, D. and Crowe, H.: Histopathological changes in human prostatic adenoma following neodymium:YAG laser ablation therapy. J. Urol., 152 1526, 1994. 26. Anson, K., Buonaccorsi, G., Eddowes, M., Macbbert, A, Mills,
T. and Watson, G.: A comparative optical analysis of laser side-firing devices: a guide to treatment. Brit. J. Urol., 7 6 328, 1995. 27. Kabalin, J. N.: Laser dosimetry studies in the human prostate. In: Application of Newer Forms of Therapeutic Energy in
Urology. Edited by M. Marberger. oxford: Isis Medical Media, pp. 143-149, 1995.
2095
28. Perhutter, A. P. and Musehter, R.: The optimization of laeer
prostatectomy. Part 1 free beam side fire coagulation. Urology, 44:847, 1994. 29. Muschter, R. and Perlmutter, A. P.: The optimization of laser prostatectomy. Part 11: other lasing techniques. Urology, 44: 856, 1994. 30. Narayan, P., Fournier, G., Indudhara, R.,
Leidich, R., Shinohara, K and Ingerman, A: Transurethrelevaporation of prostate (TUEP) with,NdYAG laser using a eontact free beam technique: results in 61 patients with benign proetatic hyperplasia. Urology, 43:813, 1994. 31. Shanberg, A M., Lee, I. S., Tansey. L. A. and Sawyer, D. E.: Extensive neodymium-YAG photoirradiation of the prostate in men with obstructive prostatism. Urology,45.467.1994. 32. Kabalin, J. N.: H0lmium:YAG laser vaporization prostatectomy. J. Urol.,part 2.153.229A, abstract 2.1995.
Vol. 164.2093-2095. Deoember 1995 Printed in U.SA
JOURNAL OF UROLOGY
Capfight 0 1995 by AMERICANU R O ~ I CASS~CUTION, AL hc.
EDITORIAL: LASER PROSTATECTOMY--WHAT WE HAVE ACCOMPLISHED AND FUTURE DIRECTIONS Within the last, few short years, neodymium:YAG laser While these represent signiscant accomplishmentsachieved prostatectomy has successfully joined the surgical ap- during a relatively short interval for a new surgical technique, proaches to the management of benign and malignant pros- and more than j e the increasing acceptance of laser prostatic obstruction of the bladder outlet. From early experimen- tatectomy in our practice, the current operative approach to tation with simple, end-firing, bare fibers14 to the important neodymium:YAG laser treatment of the prostate is not without experiences gained during development of the transurethral disadvantagea. The major drawback of current approaches in ultrasound guided laser induced prostatectomy (TULIP)de- clinical practice is the lack of immediacy of effects on voiding vice specifically for laser prostatectomy,4-6 the first of the symptoms. Whereas most patients undergoing standard transfree beam, side-firing flexible fiber delivery systems uretbral electrocauteryresection of the prostate require urinary emerged7-13 and gained acceptance as a practical transure- catheterization for 1to 3 days, and most can also expect drathral endoscopic instrument to deliver ne0dymium:YAG light matic improvement in voiding within 1week ptoperatively, energy to the prostate. Since 1992,a multitude of side-firing the physiology of ne0dymium:YAG laser ablation and coagulaneodymium:YAG laser fibers of variable configuration have tion of the prostate is much Werent. While some tissue may be been introduced, all primarily intended for use in prostatic removed acutely, the predominant effect of the neodymium: surgery. More recently, the accessibility of these delivery YAG laser in the human prostate-and the same effect that 80 systems has been combined with review and recognition of drastically limits acute operative morbidity-is tissue coagulalaser prostatectomy by the United States Health Care Fi- tion.% Thus, all patients can expect significant prostatic edema nancing Administration and American Medical Association postoperatively and ongoing loss of transition zone tissue for in conjunction with the American Urological Association to many weeks thereafter. Clinically,although many patients will allow the creation of appropriate codes in the Physicians' tolerate 1to 3 days of catheterization as mprted by Narayan et Current Procedural Terminology, thus facilitating reim- al (page 20831, most men are more wmfortable and better bursement for this operation in the United States and estab- served by 5 to 10 days with a urinary catheter (most practitiolishing laser prostatectomy in everyday urological practice. ners currently arbitrarily leave a urethral catheter in place for The advantages of laser prostatectomy are 3-fold. 1) It is an 1 week following ne0dymium:YAG laser prostatetomy). Neiefficacioustreatment for symptomatic bladder outlet obstruc- ther steroidal nor nonstemidal anti-inflammatory drugs have tion due to benign prostatic hyperplasia or prostatic carci- proved able to prevent this edema or decrease the need for noma. In randomized comparisons with transurethral elec- pastoperative cathetektion in clinical practice. Even after trwautery resection of the prostate, neodymium:YAG laser this acute phase of tissue edema subsides, most of the transition prostatectomy has consistently provided patients with simi- zone tissue loss has yet to acmr and patients will experience lar symptomatic impro~ement.1"'~With more recently avail- only gradual resolution of voiding symptoms that may continue able long-term followup of patients undergoing laser prosta- for 6 to 12 weeks or longer postoperatively. Costello et al implitectomy, this operation appears to offer durability of benefits cated ischemic as well as direct the& iqjury to the pmtatic and retreatment rates that are also similar to those of trans- transition zone to account for this ongoing, prolonged tissue urethral electrocautery resection of the prostate.18.192)Laser loss.% A uniquely innovative approach to this problem is the prostatectomy has proved to be remarkably safe, demonstrat- use of bicdegradable prostatic stents, as reported by Talja et al ing a significant decrease in short-term morbidity compared (page 2089), to allow for unimpeded urination immediately to transurethral electrocautery resection of the prostate in after ne0dymium:YAG laser prostatectomy. While such &nts these same studies.1"17 Coagulation of the prostatic paren- are still not perfected, and probably will have a desired minimal chyma by the neodymium:YAG wavelength, sealing blood functional life span of at least 12 weeks rather thanthe current vessels and preventing absorption of irrigation fluid as well 3 to 4 weeks, they promise an easy and mhimally morbid as bleeding, accounts for much of this morbidity abatement solution to post-prostatedomy voiding problems, that is an esand significantly diminishes the overall physiological stress sentially imperceptible internal catheter that requires no mainproduced by laser prostatectomy compared to transurethral tenance and that eventually removes itself after serving its electrocautery resection of the prostate. In prior studies this Purpose. A key factor limiting the wider dissemination of laser proshas been documented crudely by the lack of effects on hemoglobin or hematwrit and serum electrolyte levels9~12~13 but it tatectomy is the relative lack of experience and comfort with has now been definitively and elegantly demonstrated by a lasers for many urological practitioners, compounded by the quantitative breath ethanol techniaue in the article by confuaing multitude of laser fibers, differing laser beam conCummings et al (page 2080)in this issue of the Journal. The figuratio-ns and operative techniques proposed. Unlike elecsafety and minimal physiological stress produced by laser troresectoscopes. which are essentially interchangeable, exprostatectomy have allowed the routine surgical treatment of isting side-firing laser fibers emit beams that vary widely in Patients with severe underlying medical diseases and even angle of emission, divergence and energy density.26 These those systemically anticoagulated-groups previously of- laser beam differences demand significant variations in o p fered prostate surgery with some trepidation.20-22 Further- erative techniques that are fiber-dependent and not necesFore, laser prostatectomy appears much less likely to cause sarily interchangeable.27-29 Lacking knowledge of laser physIncontinence, impotence or urethral stricture than transure- ics and laser-tissue interactions, whether generally or for a 3) Largely specific delivery device configuration, and the matching of an thral electrocautery resection of the pro~tate.'~ because of the hemostasis and lack of physiological stress inappropriate operative technique with a given laser fiber Produced by neodymium:YAG laser prostatectomy, patients will tend to produce less than maximal voiding outcomes in Can be treated routinely on an outpatient basis, which com- practice. With a narrow, high energy density laser beam, spot bined with lower complication rates appears to offer a genu- coagulation of the prostate may produce less significant reine cost benefit for laser prostatectomy compared to trans- sults and more complications than using a slow painting or dragging technique, such as that originated with the TULIP Wethral electrocautery resection of the prostate.23 2093
2094
LASERPROSTATECTOMY
2. Kandel, L. B., Harrison, L. H.,McCullough, D. L., Boyce, W. H., Woodruff, R. P. and Dyer, R. B.: Transurethral laser prostatectomy: creation of a technique for using the neodymium: yttrium & ~ ~ ~ I Ugarnet I D WAG) laser in the canine model. J. Urol., part 2,13fl: l l O A , abstract 27, 1986. 3. Bloiso, G., Warner, R. and Cohen, M.: Treatment of urethral diseases with neodymium:YAG laser. Urology, 3 2 106,1988. 4. Assirnos, D. G., McCullough, D. L., Woodruff, R. D.,Harrison, Canine transurethral laserL. H., Hart, L. J. and Li,W.J.: induced prostateetomy. J. Endourol., 5: 145, 1991. 5. h t h , R. A. and Aretz, H. T.: Transurethral ultrasound-guided laser induced prostatectomy (TULIP procedure): a canine prostate feasibility study. J. Urol., 144% 1128, 1991. 6. McCullough, D. L., Roth, R. A, Babayan, R. K, Gordon, J. O., Reese, J, H.,Crawford, E. D., Fuselier, H. A., Smith, J. A., Murchison, R. J. and Kaye, K W.: Transurethral ultrasoundguided laser-induced prostatectomy: National Human Cooperative Study results. J. Urol., 1M): 1607,1993. 7. Johnson, D. E., Price, R. E. and Cromeens, D. M.: Pathologic changes occurring in the prostate following transurethral laser prostatectomy. Lasers Surg. Med., 1 2 254, 1992. 8. Costello, A. J., Bowsher, W. G., Bolton, D. M., Braslis, K. G. and Burt, J.: Laser ablation of the prostate in patients with benign prostatic hypertrophy. Brit. J. Urol., 6% 603, 1992. 9. Kabalin, J. N.: Laser prostatectomy performed with a right angle firing neodymium:YAG laser fiber at 40 watts power setting. J. Urol., 160:95, 1993. 10. Norris, J. P.,N o d , D. M., Lee, R. D. and Rubenstein, M. A: Visual laser ablation of the prostate: clinical experience in 108 patients. J. Urol., 160: 1612,1993. 11. Leach, G. E., Sirls, L., Ganabathi, K., Roskamp, D. and Dmochowski, R.: Outpatient visual laser-assisted prostatectomy under local anesthesia. Urology, 43: 149, 1994. 12. Kabalin, J. N., Gill, H. S. and Bite, G.: Laser prostatectomy performed with a right-angle firing ne0dymium:YAG laser fiber at 60 watts power setting. J. Urol., 153: 1502, 1995. 13. Cowles, R. S.,111, Kabalin, J. N., Childs, S., Lepor, H., Dixon, C., Stein, B. and Zabbo, A: A prospective randomized comparison of transurethral resection to visual laser ablation of the prostate for the treatment of benign prostatic hyperplasia. Urology, 44% 155, 1995. 14. Kabalin, J. N., Gill, H. S., Bite, G. and Wolfe, V.: Comparative study of laser versus electrocautery prostatic resection: 18month followup with complex urodynamic assessment. J. Urol., 15% 94, 1995. 15. Schulze, H., Martin, W., Hoch, P. and Senge, T.: TULIP vs. m.a prospective, randomized study. J. Urol., part 2, 151: 228A, abstract 3, 1994. 16. Costello, A. J. and Crowe, H. R.: A single institution experience of reflecting laser fibre prostatectomy over four years. J. Urol., part 2, 151: 229A, abstract 6, 1994. 17. Won, C., Machi, G., Theme, C., Olejniczak, G. and Lepor, H.: A prospective, double-blind, randomized study comparing the safety, efficacy and cost of laser ablation of the prostate and transurethral prostatectomy for the treatment of BPH. J. Urol., part 2, 151: 229A, abstract 7, 1994. 18. Costello, A. J. and Shaffer, B. S.: Laser ablation of benign prostatic hypertrophy (BPH): two and a half year experience with right angle delivery systems. J. Urol., part 2, 1 4 9 214A, abstract 3, 1993. 19. Kabalin, J. N., Bite, G. and Doll, S.: Neodymium:YAG laser coagulation prostatectomy: 3-year experience in 227 patients. J. Urol., in press. 20. Kabalin, J. N. and Gill, H.S.: Urolase laser prostatectomy in patients on warfarin anticoagulation: a safe treatment alternative for bladder outlet obstruction. Urology, 42: 738, 1993. 21. Miller, J., Becker, H. C., Ludwig, M., Schiefer, H.-G., Fischer, C. John N . Kabalin and Weidner, W.: Visual laser ablation of the prostate (WAF') Department of Urology in high risk patients-analysis of results and perioperative Stanford University School of Medicine morbidity. J. Urol., part 2, 153: 414A, abstract 741, 1995. 22. Kingston, T. E., Nonnenmacher, A. K, Crowe, H., Costello, A. J. Stanford, California and Street, A.: Further evaluation of transurethral laser ablation of the prostate in patients treated with anticoagulant REFERENCES therapy. Aust. New Zeal. J. Surg., 65: 40, 1995. 1. Shanberg, A. M., Tansey, L. A. and Baghdassarian, R.: The use 23. Kabalin, J. N. and Butler, E. D.: Costs of minimally invasive of the neodymium YAG laser in prostatectomy.J. Urol., part 2, laser surgery compared with transurethral electrocautery re133: 196A. abstract 331, 1985. section of the prostate. West. J. Med., 1 6 2 426, 1995.
procedure and later popularized for narrow divergence, free beam ndymium:YAG fibers.w-30 Using a fiber that emits a widely divergent, low energy density neodymium:YAG beam, spot coagulation techniques have proved optimal, while dragging techniques are relatively ineffective.27-29 A common denominator emerging for all successful operative techniques with the ne0dymium:YAG laser is the use of large amounts of ne0dymium:YAG laser energy to maximize tissue ablation, and thereby voiding outcomes. While Shanberg et al recommended energy doses of at least 1,000 JJgm. prostate tissue,31 we and many others now routinely deliver 1,500to 2,000 JJgm. or more of neodymium:YAG energy.19 Narayan et al effectively demonstrate improved results when total laser energy delivery to the prostate is more than quadrupled from a mean of 31 kJ. to nearly 130 kJ.-averaging significantly greater than 2,000 J./gm. tissue in the latter group. For the future, potential solutions to many or all of the present disadvantages of laser prostatectomy would be offered by the ability to use laser energy to vaporize obstructing prostate tissue acutely. If the low morbidity associated with neodymium:YAG laser coagulation of the prostate can be maintained, such an approach might have the dual potential of producing more immediate symptomatic improvement, thus minimizing catheterization and simplifying postoperative management, and allowing the operating surgeon to see the prostatectomy defect at operation, thus greatly simplifying intraoperative assessment of tissue treatment (in other words, "what you see is what you get") and eliminating much or all of the need for an in-depth understanding of laser physics. However, most vaporization approaches to date possess distinct disadvantages as well. Simply turning the power settings on the neodymium:YAG laser to 80 to 100 watts will produce limited tissue vaporization but the primary effect remains coagulation.= In addition, high power settings may actually limit the depth of tissue coagulation and, thus, total tissue loss during the long term,and they may also be associated with greater incidences of prostatic perforation or incontinence.m.29 The KTP laser wavelength offers little benefit over the neodymium:YAG wavelength in this application. Ne0dymium:YAG contact laser technology can effectively vaporize tissue and is more hemostatic than electrocautery. However, contact devices are less hemostatic than free beam ne0dymium:YAG tissue coagulation, tissue removal is relatively slow and contact laser prostatectomy is generally believed to be suitable only for smaller glands. Recently, use of the ho1mium:YAG laser wavelength for vaporization and resection of the prostate has proved to be much more efficient while maintaining excellent hemostasis with lack of fluid absorption.32 The minimal morbidity and immediate efficacy (overnight catheterization and transurethral electroresection-like resumption of voiding) observed following ho1mium:YAG laser vaporizationhesection in initial treatment groups should prove to be a significant advance in laser prostatectomy. Laser prostatectomy still represents a young science. The future promises further advances, and greater knowledge and understanding of this technology. With our growing experience, I believe the practitioner will witness ongoing simplification and improved ease of application of laser operative approaches in the future. Moreover, this future is probably not too distant.
LASERPROSTATECTOMY 24. Kabalin, J. N., Gong, M., Issa, M. M. and Sellers, R.: Insight into mechanism of neodymium:yttrium-aluminum-garnet laser
prostatectomy utilizing the high-power contact-free beam technique. Urology, 45: 421, 1995. 25. Costello, A. J., Bolton, D. M., Ellis, D. and Crowe, H.: Histopathological changes in human prostatic adenoma following neodymium:YAG laser ablation therapy. J. Urol., 152 1526, 1994. 26. Anson, K., Buonaccorsi, G., Eddowes, M., Macbbert, A, Mills,
T. and Watson, G.: A comparative optical analysis of laser side-firing devices: a guide to treatment. Brit. J. Urol., 7 6 328, 1995. 27. Kabalin, J. N.: Laser dosimetry studies in the human prostate. In: Application of Newer Forms of Therapeutic Energy in
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28. Perhutter, A. P. and Musehter, R.: The optimization of laeer
prostatectomy. Part 1 free beam side fire coagulation. Urology, 44:847, 1994. 29. Muschter, R. and Perlmutter, A. P.: The optimization of laser prostatectomy. Part 11: other lasing techniques. Urology, 44: 856, 1994. 30. Narayan, P., Fournier, G., Indudhara, R.,
Leidich, R., Shinohara, K and Ingerman, A: Transurethrelevaporation of prostate (TUEP) with,NdYAG laser using a eontact free beam technique: results in 61 patients with benign proetatic hyperplasia. Urology, 43:813, 1994. 31. Shanberg, A M., Lee, I. S., Tansey. L. A. and Sawyer, D. E.: Extensive neodymium-YAG photoirradiation of the prostate in men with obstructive prostatism. Urology,45.467.1994. 32. Kabalin, J. N.: H0lmium:YAG laser vaporization prostatectomy. J. Urol.,part 2.153.229A, abstract 2.1995.