Symptomatic simple renal cyst: comparison of continuous negative-pressure catheter drainage and single-session alcohol sclerotherapy.
OBJECTIVE
The purpose of this study was to evaluate whether continuous percutaneous catheter drainage with negative pressure yields better results than single-session alcohol sclerotherapy in the management of symptomatic simple renal cysts.


SUBJECTS AND METHODS
Eighty-five patients with 92 simple renal cysts were randomly assigned to two groups in a prospective controlled trial. One group was treated with sonographically guided continuous catheter drainage with negative pressure and the other group with single-session alcohol sclerotherapy. Patient demographics, clinical characteristics, treatment outcome, and complications were analyzed.


RESULTS
The initial volume of the cysts did not differ significantly between the groups, but the final volume was significantly smaller in the continuous drainage group (p = 0.026). During the 24-month follow-up period, 37 (40%) of the cysts disappeared completely: 24 (52%) of the 46 cysts in the drainage group and 13 (28%) of the 46 cysts in the sclerotherapy group (p = 0.033). In the sclerotherapy group, the probability of disappearance of the cysts was highly dependent on cyst size, being less for giant cysts (p = 0.01). Cyst size was not a significant factor in probability of disappearance in the drainage group (p = 0.15). The probability of disappearance of giant cysts (volume > 500 mL) differed significantly between the groups (p = 0.009), but there was no difference in probability of disappearance of moderately large cysts (p = 0.16). Three of 14 patients with giant cysts in the drainage group and 10 of 13 such patients in the sclerotherapy group had recurrences that necessitated additional treatment (p = 0.007). They were successfully treated with continuous catheter drainage.


CONCLUSION
Continuous catheter drainage with negative pressure is more efficient than single-session alcohol sclerotherapy in the management of giant cysts. For moderately large cysts, the two methods have similar results.