The treatment of subvesical obstruction with a spiral endoprostatic prosthesis is now well-known since Fabian's initial work (1980). A new method of insertion of the spiral with a releasable catheter and under sonographic monitoring has been proposed recently. This article is a report of a series of 35 patients. These patients presented with an adenoma of the prostate and were fitted with a permanent urethral catheter due to an absolute contraindication for anesthesia. The spiral was inserted with US monitoring in 25 patients. In 5 patients, the spiral had to be inserted under classical endoscopic control. The average follow-up period is 7.2 months. In 25 patients (75%), the spiral remained in place; the maximum flow rate of urine after the insertion averages 12.8 ml/s and 76% of these patients report an improvement of their comfort during urination. The position of the spiral had to be changed in 8 cases. No infectious complication was noted. Hematuric complications are reported in 2 cases. The spiral endoprostatic prosthesis seems to be an elegant alternative to the permanent catheter in patients at high anesthetic risk.