KTP-532 LASER ABLATION OF URETHRAL STRICTURES PAUL J. TUREK, M.D. TERRENCE R. MALLOY, M.D. MARC CENDRON, M.D.
VICTOR L, CARPINIELLO, ALAN J. WEIN, M.D.
M.D.
From the Departments of Urology, The Pennsylvania Hospital and The Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania
ABSTRACT-In 1988 the KTP-532 laser was used to ablate a series of benign urethral strictures. Rather than using a single incision as in urethrotomy, strictures were treated with 360-degree contact photoradiation. Thirty-one male patients, average age 53.2 years, received thirty-seven treatments; 6 patients underwent a second laser treatment. Stricture etiology was commonly iatrogenie (32 % ), traumatic (16 %), and postgonococcal (10 %). Stricture location included mainly bulbar (49 %), membranous (20 %), and penile (12 %) areas. The surgical technique consisted of circumferential ablation, followed by Foley catheter placement (mean, 10 days). Follow-up on 29 of 31 patients ranged from one to sixteen months (mean 9.7). Complete success occurred in 17 patients (59 %) who had no further symptoms or instrumentation. Partial success was seen in 6 patients (20.5 %) with symptom, but not stricture, recurrence. Six patients (20.5 %) failed therapy, requiring additional surgery or regular dilatations. No complications were seen. Although longer assessment is required, KTP-532 laser ablation of urethral strictures appears efficacious.
Stemming from the durable interest in the use of medical lasers in the therapy of condyloma and superficial bladder cancer, this technology has found a further focus in the treatment of benign urethral strictures. Conceptually, laser function is based on known principles of thermal effects on body tissues; effects which vary according to laser wavelength, density, and spot size.’ By varying laser type and delivery system, differences in relative degrees of coagulation, penetration, scatter, carbonization, and vaporization can be achieved. These effects have been well summarized by Smith2-4 and Malloy and Wein. Ideally, urethral strictures are best treated with minimal urethral damage, the basis for the single-incision urethrotomy. Medical lasers have different light properties which have variable tissue-damaging effects. Excessive forward scatter and coagulation from the laser energy in certain systems can result in tissue devascularization and overabundant scar formation near
330
stricture sites, precluding success. The effects of vaporization and cutting are sought, however, as fibrosis and collagen reformation at the stricture site are minimized. Initial reports with the neodymium:YAG (yttrium, aluminum garnet) laser demonstrated success rates comparable to cold knife urethrotomy in simple and complicated strictures,6-* but longer follow-up has revealed failure rates of greater than 50 percent at six to nine months.7,8 A recent report by Smith,Q using a sapphire-tipped Nd:YAG laser to enhance its cutting effect, revealed a 67 percent recurrence rate at one year. Other laser types potentially applicable to benign strictures include the CO2 and argon systems, but the experience with these is limited at present.10-12 Attention has recently turned to the use of the KTP-532 laser in urethral strictures. This is a double-frequency Nd:YAG laser passed through a second crystal (potassium-titanyl-phosphate or KTP) with a final wavelength of 532 nm. It has minimal forward scatter with a 1 mm depth
UROLOGY
/
OCTOBER
1992
/
VOLUME 40, NUMBER 4
of penetration, good carbonization, and vaporization effects and is hemostatic, making it a viable conceptual alternative to urethrotomy. A study by Shanberg et al. l3 has demonstrated 68 percent success with early follow-up using this laser. In the present report, we analyze our experience with the KTP-532 laser in benign urethral stricture disease. Material and Methods During a fifteen-month period ending in 1988, 31 patients with a history of obstructive voiding symptoms and endoscopic evidence of benign stricture disease were offered KTP-532 laser therapy. Patients with other causes of obstructive symptoms, like prostatic enlargement, were not enrolled in the study. One patient presented with a suprapubic tube in place. Of the 31 patients, 26 (84%) had prior manipulation including dilatations, urethrotomies, or and 5 (16 % ) were newly urethroplasties, diagnosed. A total of 97 prior procedures had been performed on these patients, with an average of 3.73 procedures per patient undergoing instrumentation, Laser treatment was performed with either general or regional anesthesia in an operating room setting. Patients were placed in the relaxed lithotomy position, and all strictures were confirmed with a rigid cystoscope. Stricture length and grade were estimated endoscopitally. A stricture 1-5 mm in length was deemed short; 5-10 mm, moderate; and greater than 10 mm, long. Strictures were graded as complete if the urethral lumens were completely obliterated; severe if a 4 F ureteral catheter could not be passed through a visible lumen; moderate if a 4 F catheter could pass but a 19 F cystoscope could not; and mild if a 19 F cystoscope could traverse the stricture. A ureteral stent, 4-6 F, was variably placed through the stricture prior to ablation. KTP-532 laser (Laserscope, Santa Clara, CA) was used with a power output ranging from 4-13 W, and a continuous pulse duration energy applied to the stricture in a direct contact fashion. Importantly, photoradiation was carried out to the entire circumference of the stricture, rather than using a standard 12 o’clock incision as with urethrotomy. After ablation, a Silastic catheter was inserted to stent the urethra, and the patient was discharged with the catheter on straight drainage. Catheters were removed on follow-up visits and the patients told to micturate prior to leaving the office.
UROLOGY / OCTOBER1992 i VOLUME40, NUMBER4
TABLE I.
Stricture etiology (n = 31)
Etiology
No.
Percent
Iatrogenic Unknown Traumatic Gonococcal Congenital Cancer Stones Other infections
10 6 5 3 2 1 1 3
32 19 16 10 6 3 3 10
Follow-up varied but generally patients were seen one to two weeks postoperatively and then monthly until stabilized voiding was achieved. Catheterization or sounding was done in the office if necessary, and instruction and encouragement in the routine use of clean intermittent catheterization given. Treatment efficacy was determined empirically by observation and classified as follows: Complete success was defined by the lack of obstructive voiding symptoms, along with no evidence of recurrence by either radiologic study or catheterization. Partial success was defined as symptom recurrence but without evidence of stricture by catheterization or sounds, or the lack of symptoms with urologic evidence of mild stricture by such instrumentation. Failure of therapy implied a need for operative reintervention or regular dilatations as an outpatient. Results A review of the patient population reveals the strictures to be predominantly recurrent and of diverse etiology. The age range of the patients was twenty to eighty-four years, with a mean of 53.2 years. Twenty-five patients received one KTP-532 treatment and 6 (20 % ) received two treatments. A total of forty-one strictures were treated in thirty-seven sessions. Two patients (6 % ) were lost to follow-up. Etiologically, the strictures were mostly iatrogenie in origin (32%), but traumatic (16%), postgonococcal (10 % ) , congenital (6 % ) , and unknown (13%) factors were represented as well. Table I further delineates the stricture composition. Stricture site included all urethral regions as outlined in Table II; however, bulbar (49 % ) , membranous (20 % ) , and penile (12 % ) , were the most common. Bladder neck contractures (12 % ) were also found in this series. An attempt was made to evaluate stricture length and grade for purposes of correlation to relative success with laser therapy. Figure 1
331
TABLE II.
StTiCtUTesite (n = 41) No.
Site of Stricture
n
Percent
68%
2 2 12 49
short
1
Meat al Fossa Penile Bulbar Membranous Prostatic Bladder neck
6
29
: 20 8 1 5
15% moderate
20 2 12
shows that the strictures were predominantly short (68%); however, an equivalent, but smaller, number of moderate and long strictures were also observed. Stricture length ranged from 2-30 mm. Stricture lumens, graded as above, were predominantly severe (56 % ), and less commonly moderate (30 % ) in caliber (Fig. 2). Operatively, 15 patients of 37 total (40%) received general anesthesia and the remainder underwent spinal anesthesia (60%) prior to instrumentation. Ureteral stents were placed in 18 patients (48%) as guides, Silastic Foley catheters, ranging in size from 18-24 F, were placed in all patients for a mean of 10.0 days, but varied between one and fourteen days. As 2 patients were lost to follow-up, 29 patients were followed for a mean of 9.7 months (range 1-16 months) after laser therapy. Complete success was seen in 17 patients (59 % ), and partial success observed in 6 patients (20.5%). Six men needed further regular dilatations or required reoperation (20.5 %); thus, 80 percent of patients required no further, regular instrumentation during our follow-up interval. Of those men with stricture recurrence, four of six occurred within four months of laser ablation; the other two recurred at six months and nine months (Table III). Although only 20 percent of the total patient population, those patients who had stricture recurrence had undergone 32 prior treatments (33 % ) of the 97 total prior TABLE III.
I
7
I
I
I
1-5 mm
17% long
I
5-10 mm
I
>lOmm
FIGURE 1.
Stticture length (n = 41).
FIGURE 2.
StTiCtUTe
gTade (n = 41).
treatments, averaging 5.3 procedures before KTP-532 laser therapy. Interestingly, their strictures tended to be short (71%), moderate or severe in grade (86%), and membranous or bulbar in location (86 % ), all of which were very similar to the overall group characteristics. Of those with newly diagnosed strictures, 4 of 5 patients (80%) required no further instrumentation with a mean follow-up of 9.4 months. During the follow-up of 7 patients with prior open urethroplasties, only one failure was seen. There were no intraoperative complications from KTP-532 laser therapy. Minimal hematuria was noted and postoperative pain was minimal in all cases. Besides recurrence, complications on follow-up (once the catheter was
StTictuTe TecuTTence (n = 6)
Internal to Recurrence Pt.
Etiology
(mos)
Location
Length
Grade
1
Iatrogenic Iatrogenic Congenital Traumatic Traumatic Unknown
6 4 9
Bulbar Blad. neck Bulbar Membranous Bulbar Membranous
Short Short Short Long Medium Short
Severe Moderate Severe Mild Severe Severe
: 4 5 6
332
; 3
UROLOGY /
OCTOBER1992 I VOLUME49, NUMBER4
removed) included dysuria in 4 cases, incontinence in 1 case (present prior to laser therapy), chronic perineal pain in 1 patient, and an Escherichia coli UT1 treated successfully in 1 patient. Comment Laser therapy of benign urethral strictures is conceptually attractive as this technology allows surgical resection with minimal bleeding and scar tissue formation. The laser most ideally suited to this task is the 10,600 nm CO2 laser, as it has maximum vaporative activity of the commonly used lasers. lo Unfortunately, energy of this wavelength is quickly dispersed in a fluid medium and a fiber delivery system has not been optimized as yet, precluding its use through the endoscope. Also theoretically attractive is the argon laser, used in the wavelengths of 458-515 nm. Capable of being delivered endoscopically through a fluid medium, the argon laser has been used for bladder photoradiation of tumors, but data on its use in stricture disease are more limited. 11~12 Successful experiences with the Nd:YAG laser in external lesions of the penis and scrotum, including condyloma,14 and malignancies15 have led to its use in stricture disease as well. By its versatility, easy endoscopic delivery and accurate necrosis of tissue when compared with electrocautery, 5,8it appears well suited for stricture ablation. Although performing as well as internal urethrotomy in some reports,6** other authors have demonstrated recurrence rates of 64 percent7 and 67 percent9 at six months and one year, respectively. Stricture ablation with the Nd:YAG laser is somewhat dependent on tissue coagulation with resultant sloughing, rather than vaporization and cutting of tissue. As Smith9 has reported, this may not allow sufficient increase in urethral caliber for adequate treatment. In addition, tissue sloughing may result in further postoperative voiding dysfunction by its irritative or obstructive effects. The KTP-532 laser has thermal characteristics more optimally suited for urethral stricture disease. It has minimal forward scatter and increased cutting effect secondary to its energy wavelength at 532 nm. An affinity for hemoglobin at this wavelength makes it more hemostatic than the YAG laser as well. In one series, Shanberg et al. l5 reported 68 percent patency in 20 patients with limited follow-up. Iretonle also reported five successful stricture ablations with the KTP-532 laser in 6 patients with a mean fol-
UROLOGY
/
OCTOBER
1992
/ VOLUME
40, NUMBER 4
low-up of eight months. Despite relatively short follow-up, our data reveal efficacy rates at least equivalent to internal urethrotomy in that roughly 60 percent of all patients and in 80 percent of initially treated patients, successful outcomes have been obtained. The categorization of success or failure in this study depended largely empirically on patient symptoms and on the degree of, or need for, further instrumentation. Urinary symptoms without endoscopic or other demonstration of stricture, or mild asymptomatic stricture recurrence were grouped together in a distinct category. In this manner, 20 percent of our patients are being closely followed for stricture recurrence, although overt recurrence has not yet been observed. To ascribe these results only to the increased suitability of the KTP laser over other laser systems may ignore other variables in the therapeutic regimen. The use of catheter drainage in stricture release is common, but its length of use varies considerably in different series. In this study, catheter drainage averaged ten days and was terminated in a postoperative office visit. Other investigators routinely use this approach,13 but more commonly, catheter use depends arbitrarily on stricture characteristics,g and is often considered unnecessary. 7m9Possibly, a formal study comparing laser therapy with and without catheter drainage is necessary. The technique of circumferential ablation, popularized with the YAG laser,7 was also applied in this study. Other techniques to ablate strictures include urethrotomy-style 12 o’clock photoradiatio# and multiple urethrotomies around the urethral circumference.’ No one method has been demonstrated most efficacious in laser urethrotomy, but early results using the circumferential ablative approach with KTP lasers13 have resulted in satisfactory patency rates. An organized trial of these various methods appears important in the future. In an interesting observation from these data, the comparison of stricture characteristics of those patients with recurrence and the general study population reveals no real differences in stricture grade, length, or location. Possibly, there may exist other factors besides those analyzed which may better predict stricture recurrence in these KTP-treated patients. As well, the recurrences seen were of diverse etiologies, offering no clue as to which if any type of stricture may be more refractory to laser therapy. In successful ablations, no predominance of
333
etiologic type was observed either. Of considerable potential is the demonstrated applicability of KTP laser urethrotomy to strictures of all lengths and locations, including five located in the bladder neck. Four of these strictures were successfully ablated in this study. As critical data accrue with the KTP-532 laser in urethrotomy treatment, stricture characteristics for which it is best suited may become more apparent. Urologic Center 299 South 8th Street Philadelphia, Pennsylvania 19106 (DR. MALLOY) References 1. Smith JA: Current clinical role of lasers in urologic surgery, Monogr Urol 10: 26 (1988). 2. Smith JA: Endoscopic applications of laser energy, Urol Clin North Am 13: 405 (1986). 3. Smith JA: Lasers in urologic surgery-current status, AUA Update Series, 1989, ~018, lesson 13. 4. Smith JA: Use of lasers in urological surgery, Infect Urol 1: 72 (1988).
334
5. Malloy TR, and Wein AJ: Laser technology in urology, AUA Update Series, 1984, ~013, lesson 27. 6. Shanberg AM, Chalfin SA, and Tansey LA: Neodymium:YAG laser: new treatment for urethral stricture disease, Urology 24: 15 (1984). 7. Smith JA, and Dixon JA: Neodymium YAG laser treatment of benign urethral stricture&, J Urol I31: 1080 (1984). 8. Bloiso G. Warner R. and Cohen M: Treatment of urethral diseases with Neodymium YAG laser, Urology 32: 106 (1988). 9. Smith JA: Treatment of benign urethral strictures using a sapphire-tipped Neodymium:YAG laser, J Urol 142: 1221 (1989). 10. Willscher MK: Develoument of a CO, laser cvstoscooe. in Smith JA (Ed): Lasers in Urologic Surgery, Chicago, Year’Bbok Medical Publishers, 1985, chap. 11, p 138. 11. Rothauge CF: Urethroscopic recanalization of urethral stenosis using argon laser, Urology 16: 158 (1980). 12. Adkins WC: Argon laser treatment of urethral stricture and vesical neck contracture, Lasers Surg Med 8: 699 (1988). 13. Shanberg A, Baghdassarian R, Tansey L, and Sawyer D: KTP-532 laser in the treatment of urethral strictures, Urology 32: 517 (1988). 14. Stein BS: ‘Treatment of lesions of external genitalia, in Smith JA Jr (Ed): Lasers in Urologic Surgery, Chicago, Year Book Medical Publishers, 1985, chap 3, pp 32-43. 15. Rothenberger K, Hofstetter A, Pensel J, and Keiditsch E: Neodym YAG laser behandlung maligner tumoren des penis, Fortachr Med 39: 1806 (1982). 16. Ireton RC: ‘Treatment of urologic lesions with the KTP-532 mn laser system (abstract 625), J Urol 139: 319A (1988).
UROLOGY
I
OCTOBER
1992
/ VOLUME
40, NUMBER
4
VICTOR L, CARPINIELLO, ALAN J. WEIN, M.D.
M.D.
From the Departments of Urology, The Pennsylvania Hospital and The Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania
ABSTRACT-In 1988 the KTP-532 laser was used to ablate a series of benign urethral strictures. Rather than using a single incision as in urethrotomy, strictures were treated with 360-degree contact photoradiation. Thirty-one male patients, average age 53.2 years, received thirty-seven treatments; 6 patients underwent a second laser treatment. Stricture etiology was commonly iatrogenie (32 % ), traumatic (16 %), and postgonococcal (10 %). Stricture location included mainly bulbar (49 %), membranous (20 %), and penile (12 %) areas. The surgical technique consisted of circumferential ablation, followed by Foley catheter placement (mean, 10 days). Follow-up on 29 of 31 patients ranged from one to sixteen months (mean 9.7). Complete success occurred in 17 patients (59 %) who had no further symptoms or instrumentation. Partial success was seen in 6 patients (20.5 %) with symptom, but not stricture, recurrence. Six patients (20.5 %) failed therapy, requiring additional surgery or regular dilatations. No complications were seen. Although longer assessment is required, KTP-532 laser ablation of urethral strictures appears efficacious.
Stemming from the durable interest in the use of medical lasers in the therapy of condyloma and superficial bladder cancer, this technology has found a further focus in the treatment of benign urethral strictures. Conceptually, laser function is based on known principles of thermal effects on body tissues; effects which vary according to laser wavelength, density, and spot size.’ By varying laser type and delivery system, differences in relative degrees of coagulation, penetration, scatter, carbonization, and vaporization can be achieved. These effects have been well summarized by Smith2-4 and Malloy and Wein. Ideally, urethral strictures are best treated with minimal urethral damage, the basis for the single-incision urethrotomy. Medical lasers have different light properties which have variable tissue-damaging effects. Excessive forward scatter and coagulation from the laser energy in certain systems can result in tissue devascularization and overabundant scar formation near
330
stricture sites, precluding success. The effects of vaporization and cutting are sought, however, as fibrosis and collagen reformation at the stricture site are minimized. Initial reports with the neodymium:YAG (yttrium, aluminum garnet) laser demonstrated success rates comparable to cold knife urethrotomy in simple and complicated strictures,6-* but longer follow-up has revealed failure rates of greater than 50 percent at six to nine months.7,8 A recent report by Smith,Q using a sapphire-tipped Nd:YAG laser to enhance its cutting effect, revealed a 67 percent recurrence rate at one year. Other laser types potentially applicable to benign strictures include the CO2 and argon systems, but the experience with these is limited at present.10-12 Attention has recently turned to the use of the KTP-532 laser in urethral strictures. This is a double-frequency Nd:YAG laser passed through a second crystal (potassium-titanyl-phosphate or KTP) with a final wavelength of 532 nm. It has minimal forward scatter with a 1 mm depth
UROLOGY
/
OCTOBER
1992
/
VOLUME 40, NUMBER 4
of penetration, good carbonization, and vaporization effects and is hemostatic, making it a viable conceptual alternative to urethrotomy. A study by Shanberg et al. l3 has demonstrated 68 percent success with early follow-up using this laser. In the present report, we analyze our experience with the KTP-532 laser in benign urethral stricture disease. Material and Methods During a fifteen-month period ending in 1988, 31 patients with a history of obstructive voiding symptoms and endoscopic evidence of benign stricture disease were offered KTP-532 laser therapy. Patients with other causes of obstructive symptoms, like prostatic enlargement, were not enrolled in the study. One patient presented with a suprapubic tube in place. Of the 31 patients, 26 (84%) had prior manipulation including dilatations, urethrotomies, or and 5 (16 % ) were newly urethroplasties, diagnosed. A total of 97 prior procedures had been performed on these patients, with an average of 3.73 procedures per patient undergoing instrumentation, Laser treatment was performed with either general or regional anesthesia in an operating room setting. Patients were placed in the relaxed lithotomy position, and all strictures were confirmed with a rigid cystoscope. Stricture length and grade were estimated endoscopitally. A stricture 1-5 mm in length was deemed short; 5-10 mm, moderate; and greater than 10 mm, long. Strictures were graded as complete if the urethral lumens were completely obliterated; severe if a 4 F ureteral catheter could not be passed through a visible lumen; moderate if a 4 F catheter could pass but a 19 F cystoscope could not; and mild if a 19 F cystoscope could traverse the stricture. A ureteral stent, 4-6 F, was variably placed through the stricture prior to ablation. KTP-532 laser (Laserscope, Santa Clara, CA) was used with a power output ranging from 4-13 W, and a continuous pulse duration energy applied to the stricture in a direct contact fashion. Importantly, photoradiation was carried out to the entire circumference of the stricture, rather than using a standard 12 o’clock incision as with urethrotomy. After ablation, a Silastic catheter was inserted to stent the urethra, and the patient was discharged with the catheter on straight drainage. Catheters were removed on follow-up visits and the patients told to micturate prior to leaving the office.
UROLOGY / OCTOBER1992 i VOLUME40, NUMBER4
TABLE I.
Stricture etiology (n = 31)
Etiology
No.
Percent
Iatrogenic Unknown Traumatic Gonococcal Congenital Cancer Stones Other infections
10 6 5 3 2 1 1 3
32 19 16 10 6 3 3 10
Follow-up varied but generally patients were seen one to two weeks postoperatively and then monthly until stabilized voiding was achieved. Catheterization or sounding was done in the office if necessary, and instruction and encouragement in the routine use of clean intermittent catheterization given. Treatment efficacy was determined empirically by observation and classified as follows: Complete success was defined by the lack of obstructive voiding symptoms, along with no evidence of recurrence by either radiologic study or catheterization. Partial success was defined as symptom recurrence but without evidence of stricture by catheterization or sounds, or the lack of symptoms with urologic evidence of mild stricture by such instrumentation. Failure of therapy implied a need for operative reintervention or regular dilatations as an outpatient. Results A review of the patient population reveals the strictures to be predominantly recurrent and of diverse etiology. The age range of the patients was twenty to eighty-four years, with a mean of 53.2 years. Twenty-five patients received one KTP-532 treatment and 6 (20 % ) received two treatments. A total of forty-one strictures were treated in thirty-seven sessions. Two patients (6 % ) were lost to follow-up. Etiologically, the strictures were mostly iatrogenie in origin (32%), but traumatic (16%), postgonococcal (10 % ) , congenital (6 % ) , and unknown (13%) factors were represented as well. Table I further delineates the stricture composition. Stricture site included all urethral regions as outlined in Table II; however, bulbar (49 % ) , membranous (20 % ) , and penile (12 % ) , were the most common. Bladder neck contractures (12 % ) were also found in this series. An attempt was made to evaluate stricture length and grade for purposes of correlation to relative success with laser therapy. Figure 1
331
TABLE II.
StTiCtUTesite (n = 41) No.
Site of Stricture
n
Percent
68%
2 2 12 49
short
1
Meat al Fossa Penile Bulbar Membranous Prostatic Bladder neck
6
29
: 20 8 1 5
15% moderate
20 2 12
shows that the strictures were predominantly short (68%); however, an equivalent, but smaller, number of moderate and long strictures were also observed. Stricture length ranged from 2-30 mm. Stricture lumens, graded as above, were predominantly severe (56 % ), and less commonly moderate (30 % ) in caliber (Fig. 2). Operatively, 15 patients of 37 total (40%) received general anesthesia and the remainder underwent spinal anesthesia (60%) prior to instrumentation. Ureteral stents were placed in 18 patients (48%) as guides, Silastic Foley catheters, ranging in size from 18-24 F, were placed in all patients for a mean of 10.0 days, but varied between one and fourteen days. As 2 patients were lost to follow-up, 29 patients were followed for a mean of 9.7 months (range 1-16 months) after laser therapy. Complete success was seen in 17 patients (59 % ), and partial success observed in 6 patients (20.5%). Six men needed further regular dilatations or required reoperation (20.5 %); thus, 80 percent of patients required no further, regular instrumentation during our follow-up interval. Of those men with stricture recurrence, four of six occurred within four months of laser ablation; the other two recurred at six months and nine months (Table III). Although only 20 percent of the total patient population, those patients who had stricture recurrence had undergone 32 prior treatments (33 % ) of the 97 total prior TABLE III.
I
7
I
I
I
1-5 mm
17% long
I
5-10 mm
I
>lOmm
FIGURE 1.
Stticture length (n = 41).
FIGURE 2.
StTiCtUTe
gTade (n = 41).
treatments, averaging 5.3 procedures before KTP-532 laser therapy. Interestingly, their strictures tended to be short (71%), moderate or severe in grade (86%), and membranous or bulbar in location (86 % ), all of which were very similar to the overall group characteristics. Of those with newly diagnosed strictures, 4 of 5 patients (80%) required no further instrumentation with a mean follow-up of 9.4 months. During the follow-up of 7 patients with prior open urethroplasties, only one failure was seen. There were no intraoperative complications from KTP-532 laser therapy. Minimal hematuria was noted and postoperative pain was minimal in all cases. Besides recurrence, complications on follow-up (once the catheter was
StTictuTe TecuTTence (n = 6)
Internal to Recurrence Pt.
Etiology
(mos)
Location
Length
Grade
1
Iatrogenic Iatrogenic Congenital Traumatic Traumatic Unknown
6 4 9
Bulbar Blad. neck Bulbar Membranous Bulbar Membranous
Short Short Short Long Medium Short
Severe Moderate Severe Mild Severe Severe
: 4 5 6
332
; 3
UROLOGY /
OCTOBER1992 I VOLUME49, NUMBER4
removed) included dysuria in 4 cases, incontinence in 1 case (present prior to laser therapy), chronic perineal pain in 1 patient, and an Escherichia coli UT1 treated successfully in 1 patient. Comment Laser therapy of benign urethral strictures is conceptually attractive as this technology allows surgical resection with minimal bleeding and scar tissue formation. The laser most ideally suited to this task is the 10,600 nm CO2 laser, as it has maximum vaporative activity of the commonly used lasers. lo Unfortunately, energy of this wavelength is quickly dispersed in a fluid medium and a fiber delivery system has not been optimized as yet, precluding its use through the endoscope. Also theoretically attractive is the argon laser, used in the wavelengths of 458-515 nm. Capable of being delivered endoscopically through a fluid medium, the argon laser has been used for bladder photoradiation of tumors, but data on its use in stricture disease are more limited. 11~12 Successful experiences with the Nd:YAG laser in external lesions of the penis and scrotum, including condyloma,14 and malignancies15 have led to its use in stricture disease as well. By its versatility, easy endoscopic delivery and accurate necrosis of tissue when compared with electrocautery, 5,8it appears well suited for stricture ablation. Although performing as well as internal urethrotomy in some reports,6** other authors have demonstrated recurrence rates of 64 percent7 and 67 percent9 at six months and one year, respectively. Stricture ablation with the Nd:YAG laser is somewhat dependent on tissue coagulation with resultant sloughing, rather than vaporization and cutting of tissue. As Smith9 has reported, this may not allow sufficient increase in urethral caliber for adequate treatment. In addition, tissue sloughing may result in further postoperative voiding dysfunction by its irritative or obstructive effects. The KTP-532 laser has thermal characteristics more optimally suited for urethral stricture disease. It has minimal forward scatter and increased cutting effect secondary to its energy wavelength at 532 nm. An affinity for hemoglobin at this wavelength makes it more hemostatic than the YAG laser as well. In one series, Shanberg et al. l5 reported 68 percent patency in 20 patients with limited follow-up. Iretonle also reported five successful stricture ablations with the KTP-532 laser in 6 patients with a mean fol-
UROLOGY
/
OCTOBER
1992
/ VOLUME
40, NUMBER 4
low-up of eight months. Despite relatively short follow-up, our data reveal efficacy rates at least equivalent to internal urethrotomy in that roughly 60 percent of all patients and in 80 percent of initially treated patients, successful outcomes have been obtained. The categorization of success or failure in this study depended largely empirically on patient symptoms and on the degree of, or need for, further instrumentation. Urinary symptoms without endoscopic or other demonstration of stricture, or mild asymptomatic stricture recurrence were grouped together in a distinct category. In this manner, 20 percent of our patients are being closely followed for stricture recurrence, although overt recurrence has not yet been observed. To ascribe these results only to the increased suitability of the KTP laser over other laser systems may ignore other variables in the therapeutic regimen. The use of catheter drainage in stricture release is common, but its length of use varies considerably in different series. In this study, catheter drainage averaged ten days and was terminated in a postoperative office visit. Other investigators routinely use this approach,13 but more commonly, catheter use depends arbitrarily on stricture characteristics,g and is often considered unnecessary. 7m9Possibly, a formal study comparing laser therapy with and without catheter drainage is necessary. The technique of circumferential ablation, popularized with the YAG laser,7 was also applied in this study. Other techniques to ablate strictures include urethrotomy-style 12 o’clock photoradiatio# and multiple urethrotomies around the urethral circumference.’ No one method has been demonstrated most efficacious in laser urethrotomy, but early results using the circumferential ablative approach with KTP lasers13 have resulted in satisfactory patency rates. An organized trial of these various methods appears important in the future. In an interesting observation from these data, the comparison of stricture characteristics of those patients with recurrence and the general study population reveals no real differences in stricture grade, length, or location. Possibly, there may exist other factors besides those analyzed which may better predict stricture recurrence in these KTP-treated patients. As well, the recurrences seen were of diverse etiologies, offering no clue as to which if any type of stricture may be more refractory to laser therapy. In successful ablations, no predominance of
333
etiologic type was observed either. Of considerable potential is the demonstrated applicability of KTP laser urethrotomy to strictures of all lengths and locations, including five located in the bladder neck. Four of these strictures were successfully ablated in this study. As critical data accrue with the KTP-532 laser in urethrotomy treatment, stricture characteristics for which it is best suited may become more apparent. Urologic Center 299 South 8th Street Philadelphia, Pennsylvania 19106 (DR. MALLOY) References 1. Smith JA: Current clinical role of lasers in urologic surgery, Monogr Urol 10: 26 (1988). 2. Smith JA: Endoscopic applications of laser energy, Urol Clin North Am 13: 405 (1986). 3. Smith JA: Lasers in urologic surgery-current status, AUA Update Series, 1989, ~018, lesson 13. 4. Smith JA: Use of lasers in urological surgery, Infect Urol 1: 72 (1988).
334
5. Malloy TR, and Wein AJ: Laser technology in urology, AUA Update Series, 1984, ~013, lesson 27. 6. Shanberg AM, Chalfin SA, and Tansey LA: Neodymium:YAG laser: new treatment for urethral stricture disease, Urology 24: 15 (1984). 7. Smith JA, and Dixon JA: Neodymium YAG laser treatment of benign urethral stricture&, J Urol I31: 1080 (1984). 8. Bloiso G. Warner R. and Cohen M: Treatment of urethral diseases with Neodymium YAG laser, Urology 32: 106 (1988). 9. Smith JA: Treatment of benign urethral strictures using a sapphire-tipped Neodymium:YAG laser, J Urol 142: 1221 (1989). 10. Willscher MK: Develoument of a CO, laser cvstoscooe. in Smith JA (Ed): Lasers in Urologic Surgery, Chicago, Year’Bbok Medical Publishers, 1985, chap. 11, p 138. 11. Rothauge CF: Urethroscopic recanalization of urethral stenosis using argon laser, Urology 16: 158 (1980). 12. Adkins WC: Argon laser treatment of urethral stricture and vesical neck contracture, Lasers Surg Med 8: 699 (1988). 13. Shanberg A, Baghdassarian R, Tansey L, and Sawyer D: KTP-532 laser in the treatment of urethral strictures, Urology 32: 517 (1988). 14. Stein BS: ‘Treatment of lesions of external genitalia, in Smith JA Jr (Ed): Lasers in Urologic Surgery, Chicago, Year Book Medical Publishers, 1985, chap 3, pp 32-43. 15. Rothenberger K, Hofstetter A, Pensel J, and Keiditsch E: Neodym YAG laser behandlung maligner tumoren des penis, Fortachr Med 39: 1806 (1982). 16. Ireton RC: ‘Treatment of urologic lesions with the KTP-532 mn laser system (abstract 625), J Urol 139: 319A (1988).
UROLOGY
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OCTOBER
1992
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40, NUMBER
4
