Ho:YAG Laser in Endoscopic Treatment of Ureteral Strictures
Mazo E, Zenkov S, Chepurov A, Kozdoba A

OBJECTIVE: Such advantages of the 2.09-wave Ho-YAG laser as a 0.4-mm penetration depth of a single pulse, absence of tissue carbonization, dry operative field, and its ability to dissect and evaporate tissues have proved to allow its application in treatment of ureteral strictures.

PATIENTS AND METHODS: The Ho-YAG laser was used in 23 patients during 24 surgical interventions for ureteral stricture in 12 women and 11 men. The radiation parameters had experimentally been determined in vivo during nephroureterectomy carried out for renal cancer. The antegrade access was performed in 11 patients, and the retrograde one in 12. The stricture length was from 0.6 to 1.4 cm in 9 subjects, from 0.3 to 0.4 cm in 5, and up to 0.3 cm in 9 patients. Of them, 8 patients had primary stricture, 15 secondary strictures. Eight subjects had developed uteropelvic stricture following pyelolithotomy (length 0.4 -1.4 cm), five after gynaecological surgery in the lower third of the ureter (length 0.3 - 0.4 cm), and two after ultrasonic lithotripsy and lithoextraction (length up to 0.3 cm). These 15 patients with secondary strictures were subjected to dissection combined with ablation of cicatricial tissues. Eight patients with primary strictures underwent only stricture dissection. The operations were completed by indwelling the inner ureteral stent which remained for an average of 8 weeks (8 - 12 weeks). Satisfactory restoration of the ureter was achieved in all the patients involved.

OUTCOMES: In 12 weeks, renal function improvement (with an average increase of 23.5%) was obtained in 13 (86%) out of 15 patients with secondary strictures. The follow-up examination of these patients after 12 - 24 months showed no functional alterations, renal secretory function was noted to decrease by 10% in one patient, and by 15% in another. Examination of 8 patients with primary stricture 16 - 24 months later showed that the renal functional indices remained at the preoperative level in 2 subjects, while 6 patients demonstrated an increase of 15 - 28% (averagely by 21.5%). Hence, the efficacy of treating ureteral secondary strictures with the Ho-YAG laser amounted to 93.3% (14 of 15 patients), that of primary stricture was 75% (6 of 8 patients), the total efficacy amounting to 88.2% (20 of 23 patients).

CONCLUSION: The holmium-laser endopyeloplasty in the form of endoureteropyelotomy proved to allow for a layer-by-layer dissection of the ureteral wall, to be performed visually, without inflicting lesions to the vessels, and with ablation of not only ureteral scars, but sclerotic paraureteral (parapelvic) tissues, as well. This leads to forma-tion of an elastic operative scar due to the absence of tissue coagulation in the operation field. Taken together, these peculiarities seem to provide a means for a faster recovery of the urodynamic and functional indices of the upper urinary tract.

Journal of Endourology, Vol. 13 Supplement 1, A84, Sep 1999

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