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Year : 2000  |  Volume : 17  |  Issue : 1  |  Page : 37-40

Advantages of fulguration of posterior urethral valves by Nd: YAG laser

Department of Pediatric Surgery, All India Institute of Medical Sciences, New Delhi, India

Correspondence Address:
D K Gupta
Department of Pediatric Surgery, All India Institute of Medical Sciences, New Delhi - 110 029
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Source of Support: None, Conflict of Interest: None

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Posterior Urethral Valves (PUV) are one of the com­monest urolgical problems seen in children and the electro­coagulation, which is the most widely preferred modality to ablate the valves, may not be feasible in small-for-date and low-birth-weight neonates as the suitable size resec­toscope/cystoscope may not available. With the availa­bility of Nd: YAG laser at our institute recently, we started performing the laser fulguration instead of electrocoagu­lation of the valves. We reviewed our experience with the emerging role of the Nd: YAG laser in the fulguration of PUV, comparing the results with a historical control group who underwent the classical electrocoagulation of the PUV. The boys (n=50) diagnosed to have PUV by VCUG were confirmed by Wolf 8.5 size cystoscope, underwent Nd: YAG laser fulguration of the valves with a bare fiber, as a day-care procedure without postoperative catheteri­zation. Historical controls (n=50) who had undergone classical electrocoagulation using 9.5 size Wolf resectos­cope served as the controls. The mean age was 1.3 y and 2.6 y in laser and electrocoagulation group respectively. The mean hospital stay of the electrocoagulation group was 3.8 d. Three patients after electrocoagulation devel­oped hematuria and 4 required refulguration whereas in the laser group 5 required refulguration and none devel­oped hematuria. In conclusion, endoscopic laser fulgura­tion of PUV is technically feasible even in neonates and small children. Laser offers excellent results that are com­parable to the time-honored electrocoagulation procedure. This has the additional advantage forfulgurating the PUV in smaller caliber urethra as this can be performed with the smaller available cystoscope that has a side channel, admitting the laser fiber.

Keywords: Urethral Valve; Child; Laser; Electrocoagulation; Complication.

How to cite this article:
Gupta D K, Bajpai M, Charles A R, Srinivas M, Dave S, Lal A, Gupta A K. Advantages of fulguration of posterior urethral valves by Nd: YAG laser. Indian J Urol 2000;17:37-40

How to cite this URL:
Gupta D K, Bajpai M, Charles A R, Srinivas M, Dave S, Lal A, Gupta A K. Advantages of fulguration of posterior urethral valves by Nd: YAG laser. Indian J Urol [serial online] 2000 [cited 2023 Feb 5];17:37-40. Available from:

   Introduction Top

Posterior Urethral Valves (PUV) are one of the most common urological problems having wide clinical impli­cations and the prognosis depends upon the extent of the renal injury inflicted by the time of initiation of interven­tion and hence earlier the treatment, better the long-term outcome. The management of these valves has changed over the years from avulsion techniques, [1] open resection, [2] prolonged catheterisation, [3] fluoroscopy-guided hook ab­lation [4] to the electrocoagulation. [5] The Neodymium: yt­trium-aluminum-garnet (Nd: YAG) laser has an established place in Urology and has become a common tool for treat­ment of various adult urology diseases. [6] However, its use in pediatric urology is still limited. The electrocoagula­tion is the most preferred treatment of PUV all over the world. However, at our center, with the available electro­coagulation unit (9.5 size resectoscope) we faced a unique problem to negotiate the resectoscope into the needy newborns' urethra in a substantial proportion of the ba­bies who were small for date, low birth weight, or the ba­bies with PUV having growth retardation. Such neonates were offered the initial diversion thus necessitating a de­lay for the definitive fulguration. However, the Nd: YAG laser has obviated this problem by allowing cystoscopy and fulguration of PUV even in the low-birth-weight neonates as this can be negotiated through the side chan­nel of the 8.5 cystoscope. We reviewed our experience with the use of the Nd: YAG laser in the fulguration of PUV and compared the results with a historical control group who had undergone the classical electrocoagula­tion of the PUV at our center.

   Material and Methods Top

50 boys aged between 5 days and 4 years, diagnosed to have PUV by voiding cystourethrogram (VCUG) under­went cystoscopy on a day-care surgery basis under gene­ral anesthesia. The diagnosis was confirmed and Nd: YAG laser fulguration of the PUV was performed. The procedure was performed in the lithotomy position using the Wolf 8.5 cystoscope and the 25° telescope. This angled telescope helps to keep the laser beam under visual con­trol throughout the fulguration. After identifying the valves, the 600µ quartz bare fiber of the laser is passed through the side channel of the cystoscope and brought in direct contact with the valves that were then fulgurated. The bare fiber was brought in contact with the central portion of the valves that were then vaporized advancing centrifugally. The laser power setting ranged from 25-30 Watts and the total energy delivered each time ranged from 160-756 Joules, with a meanof 316 Joules. No attempt was made to vaporize the valves all around completely so as to reduce the chances of laser injury to the surrounding structures. The adequacy of the fulguration was checked in the operating room by observing the urinary stream. The children were discharged after the procedure and re­viewed at 3 months with VCUG. Follow-up extended from 2 months to 36 months with a mean of 18 months. His­torical controls consisted of patients with PUV (n=50) who had undergone cystoscopy and electro-coagulation of the valves during the time period 1995-1997 at our institute.[Table 1]

   Results Top

The mean age of children in the group treated by laser fulguration was 1.3 years (range: 5 days-4 years) while the mean age in the electrocoagulation group was 2.6 years (range: 5 months-6 years). Post-fulguration urinary stream was satisfactory in both groups at the operating room. In the electrocoagulation group, all the children were cathe­terized after fulguration and were hospitalized for a pe­riod ranging from 48 hours to 5 days and this was the protocol at our center. All the patients in the laser group were treated on an outpatient basis and were not cathete­rized. Three patients in the electrocoagulation group had hematuria in the postoperative period, which was self-lim­iting. Upon suspicion of poor stream of urine at the fol­low-up, check cystoscopy was performed in 5 patients belonging to the laser fulguration group and 4 patients in the electrocoagulation group and the valves were reful­gurated with the respective modalities. These refulgurated patients underwent follow-up with VCUG at 3 months and showed no further evidence of residual valves. The pro­file of both the groups is depicted in the table. It is evident from this table that with the application of Nd: YAG laser the age profile has shifted towards younger age. This is due to the fact more and more younger patients are being offered the laser fulguration at an early age which is feasi­ble with this modality.

   Discussion Top

This study has shown that Nd: YAG is a good modality for fulguration of the PUV in children. In 1984, Nd: YAG was approved for the treatment of bladder cancer by FDA of USA and this has now expanded its role. It is now be­ing used in the treatment of various urolgical conditions like intraurethral condylomata, transitional cell carcinoma, benign prostatic hyperplasia and urethral stricture dis­ease. [7],[8] The use of laser for fulguration of posterior ure­thral valves has been described in a few reports, [9],[10] albeit in a small number of cases. The Nd: YAG laser offers an alternate modality for ablation of the valves, with a very high precision. This laser works by the various physical principles that interact between the tissue and the laser and is primarily determined by absorption - which is es­sential for the conversion of the light energy to thermal energy. With the contact of laser energy with the valves, the thermal effect is triggered, whereby the light energy is transformed to heat and consequently there is tissue dena­turation followed by carbonization and tissue vaporiza­tion. [11] So the primary effects of Nd:YAG laser fulguration is the thermal ablation of the valves with negligible va­porization. This is similar to the electrocoagulation but the laser has lower penetration and surrounding injury if the pulse and the duration are modified to suit the needs. It has been shown that with the use of the laser there is slough formation and after this re-epithelialisation occurs without scarring or fibrosis. [12] Keiditsch et al performed animal experiments and it was reported that the Nd:YAG laser has the advantage of causing a circumscribed tissue necrosis with a well-defined depth, that is controlled pre­cisely and is constant and reproducible as opposed to electrocoaguation which is less homogenous. [13]

It is important to keep the duration of the laser bursts to a short time so as to limit the extent of the injury and give the pause between the bursts so as to lower the overall energy delivered. Limiting the pulse duration of the laser to 0.2 seconds with intervals of 0.3 seconds permits the underlying tissue to spread thermal injury during the pauses, thus limiting the depth of tissue affected by the laser. Pulse duration < 0.2 seconds also greatly reduces the possibility of self-destruction of the fiber tip. The de­livery of the laser as a pulsed mode of delivery instead of a steady continuous mode further helps as it allows a lower total quantity of energy with a higher peak power, im­proving the cutting characteristics of the device. Also, when the laser fiber is used in the contact mode, the fiber mainly causes tissue vaporization and seems to be the best choice for this purpose, with minimal extension of the energy into surrounding periurethral tissues. [14] Using elec­trocautery, a stricture urethra at the site of fulguration has been reported, with the incidence varying from 1-8% [9] to 8-25%. [15],[16],[17] With the high precision of the laser beam and the limited penetration of the energy when used in the contact pulsed mode, there is significant reason to believe that the rate of urethral stricture following laser coagula­tion will be significantly lesser. The reported damage to the sphincter and the subsequent urinary incontinence described after electrocoagulation [18] should be lesser with the laser. These theoretical advantages need to be corrobo­rated by long-term follow-up studies.

The 8.5 cystoscope allows endoscopy of the urethra and bladder even in low-birth-weight infants. This is especially relevant in our setup where the substantial proportion of infants are of low birth weight and small for date in whom it was difficult to negotiate the 9.5 resectoscope available with us. The Nd: YAG laser beam is transmitted by ad­vancing the 600µ bare fiber through the side channel of the cystoscope and this retrograde endoscopic laser appli­cation in the neonate is technically feasible, thus allowing early ablation of the valves. Early fulguration of the valves gives a chance for better bladder function and cycling. Many authors have stressed the better function and urodynamic characteristics of the bladder which has not been diverted compared to a diverted bladder. [19],[20],[21] The earlier the valves are ablated, the need for secondary pro­cedures has been reported to be fewer. [22]

In conclusion, endoscopic laser fulguration of PUV is technically feasible even in neonates and small children. It offers excellent results that are comparable to the time­honored electrocoagulation, with an additional advantage for fulgurating the PUV in smaller caliber urethra as this can be performed with the smaller available cystoscope that has a side channel. However, long-term studies are indicated in evaluation of strictures, ejaculatory abnor­malities and continence after fulguration with the Nd: YAG laser as the studies with this new modality are few and only short-term results have been reported.

   References Top

1.Williams DI, Whitaker RH, Barratt TM, Keeton JE. Urethral valves. Br J Urol 1973; 45: 200-210.  Back to cited text no. 1  [PUBMED]  
2.Johnston JH. Posterior Urethral Valves - an open operative tech­nique using electric auriscope. J Ped Surg 1966: 1: 583-584.  Back to cited text no. 2    
3.Brandensky G. Conservatively treated urethral valves. J Ped Surg 1973: 8: 945-947.  Back to cited text no. 3    
4.Whitaker RH, Sherwood T. An improved hook for destroying pos­terior urethral valves. J Urol 1986: 135: 531-532.  Back to cited text no. 4    
5.Hendren WH. Posterior Urethral Valves in boys - A broad clinical spectrum. J Urol 1971; 106: 298-307.  Back to cited text no. 5  [PUBMED]  
6.Stein BS. Kendall AR. The use of the Nd: YAG laser in urology. Lasers Surg Med 1985; 5: 129-132.  Back to cited text no. 6    
7.Staehler G. Chaussy C, Jocham D, Schmiedt E. The use of neo­dymium-YAG lasers in urology: indications, technique and critical assessment. J Urol 1985: 134: 1155-1160.  Back to cited text no. 7    
8.Faerber GJ, Park JM, Bloom DA. Treatment of Pediatric urethral stricture disease with Nd: YAG laser. Urology 1994; 44: 264-267.  Back to cited text no. 8  [PUBMED]  [FULLTEXT]
9.Biewald W. Schier F. Laser treatment of posterior urethral valves in neonates. Br J Urol 1992: 69: 425-427.  Back to cited text no. 9    
10.Ehrlich RM. Shanberg A, Fine RN. Nd: YAG laser ablation of pos­terior urethral valves. J Urol 1987: 138: 959-962.  Back to cited text no. 10    
11.Floratos DL, Rosette JJMCH. Lasers in Urology. BJU Int 1999 - .84: 204-211.  Back to cited text no. 11    
12.Smith JA Jr. Dixon JA. Nd:YAG laser treatment of benign urethral strictures. J Urol 1984: 131: 1080-1081.  Back to cited text no. 12    
13.Keiditsch E. Hofstetter A, Rothenberger K. Comparative morpho­logical investigations of effects of Nd:YAG laser and electrocoagu­lation in experimental animal research. In: Gynecologic Laser Surgery. BellinaJH (ed.). New York: Plenum 1981; 327-336.  Back to cited text no. 13    
14.Berlein HP. Biewald W, Phillip C. Laser use in pediatric urology surgery. Dialogues in Pediatric Urology 1990; 13: 5-8.  Back to cited text no. 14    
15.Hendren WH. Complications of urethral valve surgery. In: Compli­cations of Urological Surgery, Smith RB. Philadelphia: Saunders, 1976; 307.  Back to cited text no. 15    
16.Crooks KK. Urethral strictures following transurethral resection of posterior urethral valves. J Urol 1982: 127: 1153-1154.  Back to cited text no. 16    
17.Churchill BM. Krueger RP, Fleisher MH. Complications of poste­rior urethral valve surgery and their prevention. Urol Clin North Am 1983: 10: 519-526.  Back to cited text no. 17    
18.Crooks KK. The protean aspects of Posterior Urethral Valves. J Urol 1981: 126: 763-766.  Back to cited text no. 18    
19.Smith GHH. Duckett JW. In: Pediatric Urology (3 rd ed.). Mosby. 2412.  Back to cited text no. 19    
20.Monford G. Posterior Urethral Valve management. Presented at So­ciety for Pediatric Urology Surgeons meeting. Dublin, 1994.  Back to cited text no. 20    
21.Hendren WH. Urinary tract refunctionalisation after long-term di­version: A 20-year experience with 177 patients. Ann Surg 1990: 212: 478-495.  Back to cited text no. 21    
22.King LR. Posterior urethral valves. In: Clinical Pediatric Urology. Kelalis P, King LR and Belman AB (eds.). Philadelphia: Saunders, 1985: 527.  Back to cited text no. 22    


  [Table 1]


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