Sono-urethrography in the evaluation of anterior urethral strictures

During a 7-year period 123 paired urethrographic and sono-urethrographic studies were performed on 101 patients with 110 urethral strictures. In all but 3 cases the urethra was subsequently evaluated either cystoscopically or at open operation. Sono-urethrography readily identified urethral calculi, diverticula and false passages. It correctly identified the stricture and its site in every case. There was a significant difference between stricture length as measured by urethrography compared to that measured by sono-urethrography (p < 0.003). However, if the strictures were grouped based on anatomical location, there was good correlation and no significant difference in the penile urethra (correlation coefficient = 0.94, p = 0.74) but poor correlation and the significant difference remained in the urethral bulb (correlation coefficient = 0.64, p < 0.007). Similarly, when urethrographic and sono-urethrographic stricture lengths were compared with operative lengths, in the penile urethra the correlation coefficients were close (correlation coefficient = 0.91 versus 0.98) but in the urethral bulb the poor correlation persisted (correlation coefficient = 0.69 versus 0.89). Although sono-urethrography certainly identifies periurethral tissue, it was unreliable in predicting the depth of spongiofibrosis when compared with full depth biopsies in 36 patients with histopathological correlation. Finally, in 16% of the patients sono-urethrography correctly indicated a reconstructive procedure different from that originally suggested by conventional urethrography. Sono-urethrography is a dynamic 3-dimensional study that accurately identifies stricture site, number and caliber. Compared with conventional urethrography, it more accurately measures stricture length and diameter, and identifies periurethral tissue, making it a valuable adjunct in the evaluation of patients with suspected anterior urethral strictures.