Evaluation of transrectal voiding ultrasonography in men with micturition difficulties without apparent organic obstruction of the lower urinary tract.

Abstract

To examine whether transrectal voiding ultrasonography (TRVUS) can evaluate voiding movement in men with dysfunctional voiding. Ninety-nine consecutive men complaining of voiding difficulties without benign prostatic hyperplasia, prostatic cancer, severe bladder neck contracture and urethral stricture received uroflowmetry and TRVUS. Those who had abnormal findings on both uroflowmetry and TRVUS underwent subsequent cystometry combined with electromyography (EMG) to confirm the presence of dysfunctional voiding. Uroflowmetry indicated abnormal findings in 31 of the 99 patients, and TRVUS demonstrated abnormal movements of the posterior urethra during voiding in all of these 31 patients and 11 of the other 68 patients whose uroflowmetry did not indicate abnormality. TRVUS findings of the former 31 were divided into type E (the external urethral sphincter closed or intermittently opened while the bladder neck manifested an opening movement of > 7 mm during voiding in 20) and type I (both the bladder neck and external urethral sphincter manifested an intermittent movement of < 7 mm in 11). Subsequent cystometry combined with EMG in the 31 patients who had abnormal findings on both uroflowmetry and TRVUS revealed overactivity of the external urethral sphincter (OS) and underactivity of the detrusor (UD) in 85 and 35% of type-E group and 55 and 73% of type-I group, respectively. Type E included significantly more OS without UD than type I (65 vs. 18%; p = 0.0233). All of type-E (20/20) and 91% of type-I (10/11) patients had voiding difficulty which resulted from either OS or UD, while a very limited number of patients (4/31) manifested neurological symptoms such as paraplegia except for voiding difficulties. Both uroflowmetry and TRVUS are easy and useful methods to evaluate dysfunctional voiding in men, especially when neural disorders or organic obstruction of the lower urinary tract are not apparent.