The effectiveness and complications of the treatment of detrusor-external sphincter dyssynergia (DESD) and voiding pressure > 60 mm H2O using an endoluminal urethral sphincter prosthesis (Urolume) were compared with those of conventional external sphincterotomy in 46 men with spinal cord injury (SCI) (mean age 34 years; range 18-58 years). Twenty-six patients elected the Urolume, and 20 chose sphincterotomy. The age and level and duration of SCI were similar in the two groups. Follow-up ranged from 6 to 20 months. After prosthesis placement, voiding pressure dropped from 88 +/- 29 cm H2O to 38 +/- 22 cm H2O at 6 months (n = 23) and 35 +/- 16 cm H2O at 12 months (n = 18) (P < 0.001). The residual urine volume fell from 180 +/- 145 mL preoperatively to 85 +/- 125 mL at 12 months (P < 0.001), while the maximum cystometric capacity remained constant (P = 0.75). External sphincterotomy achieved similar statistically significant decreases in voiding pressure and residual urine volume, and bladder capacity was maintained. The preoperative and follow-up urodynamic measures were similar in the two groups. Prosthesis placement was associated with a significantly shorter operation (P = 0.001) and length of hospitalization (P = 0.01), a lower hospitalization cost (P = 0.01), and less bleeding (change in hemoglobin concentration) (P = 0.01) than external sphincterotomy. The complications of stent insertion were device migration (n = 4) and secondary bladder neck obstruction (n = 2). One patient with continuing reflux required bilateral ureteral implantation. The complications of sphincterotomy were bleeding necessitating transfusion (n = 2), recurrent obstruction (n = 2), and erectile dysfunction (n = 1). The sphincter prosthesis is as effective as sphincterotomy in the treatment of DESD, while being technically easier, less morbid, and less expensive.