[Therapeutic indications and complementary explorations in benign prostatic hypertrophy: significance of simultaneous recordings].

Dysuria due to obstruction by benign prostatic hypertrophy causes an increase in the bladder work and constitutes the origin of alterations in the bladder wall. Although initially reversible, the progression towards fibrosis makes recovery increasingly incomplete the longer the treatment is delayed. The detection and evaluation of increased bladder work in the presence of early obstruction allows treatment to be instituted early in the natural history of the disease. Although clinical examination may be suggestive of bladder neck obstruction, it is neither characteristic of the bladder repercussions nor sufficient to define a population at risk. Similarly, voiding urethrography, uroflowmetry or cystomanometry, taken separately, are unable to assess bladder work early in the disease. However, bladder work can be studied by recording the voiding intravesical pressure (measured by a suprapubic catheter) in relation to the urine flow (measured by uroflowmetry). By studying the variations in voiding pressure in relation to initiation of micturition, a parameter can be defined which is useful for the therapeutic indication: the PVOP (pre-voiding opening pressure of the bladder neck), which is able to distinguish 2 mechanisms of obstruction: "compression" characterised by a raised PVOP, as in the case of benign prostatic hypertrophy, and "stenosis", with an unchanged PVOP, as in the case of urethral stricture. Re-evaluation after prostatectomy shows a return to normal of the PVOP. The difficulty of routinely inserting a suprapubic catheter has led to the development of indirect approaches, particularly voiding hydrodynamic morphological or transrectal ultrasonographic methods.