The role of transabdominal ultrasound in the preoperative evaluation of patients with benign prostatic hypertrophy.

We evaluated 59 consecutive patients for obstructive voiding symptoms with physical examination, excretory urography, urethrocystoscopy, post-voiding residual volumes, uroflowmetry and transabdominal ultrasound of the prostate. Of the patients 53 underwent transurethral resection of the prostate and 6 underwent open prostatectomy. Followup uroflowmetry was done 4 weeks postoperatively. The best predictor of the actual prostatic weight was transabdominal ultrasound (r equals 0.975), and with digital rectal examination and urethrocystoscopy there was a tendency to overestimate small and underestimate large glands. Symptoms such as nocturia do not allow any conclusions about the size of the prostate. The correlation between post-void residual and specimen weight also is poor and only patients in retention (Foley catheter) have a significantly larger prostate. Preoperative uroflowmetry provides limited information about the prostatic size but, although the difference between the preoperative and postoperative flow rate index is highly significant (p less than 0.001, mean difference test), the correlation between specimen weight, and the difference between preoperative and postoperative flow rate index is not significant. We recommend transabdominal sonography of the prostate, a simple and noninvasive procedure, as a useful adjunct in the preoperative evaluation of patients with benign prostatic hypertrophy. In addition to the fact that only this method provides reliable and reproducible estimations of the weight of the prostate, further information, such as measurement of the post-void residual volume, can be obtained without additional costs or loss of time.