The infravesical obstruction in women is admittedly a cause of urination dysfunction, nevertheless its physiopathology has not been completely elucidated. The main symptoms are difficulty to begin urination, force decrease and the caliber of the urine flow, intermittent flow and a sensation of incomplete emptying of the bladder. Notwithstanding Massey & Abrams1 observed only 40% of obstructive symptoms in women whose urodynamic study had revealed obstruction, showing a low correlation between obstructive urination symptoms and the infravesicle obstruction in women. The female urethra is a fibrous muscular tube of 3 to 5 cm in length covered by a transitional stratified epithellum that originates proximally to the bladder, it is distally squamous, derived from the vulvar epithellum2. We also observe estrogenic receptors on its wall 1,3,4 , in larger amount in the distal urethra4.
The normal caliber of the urethra is quite discussible, Uehling5, in 1978, studying 250 women with no urinary complaints or any other important alterations, we observed that the urethral caliber was in average 22Fr. Gleason6 observed a negative correlation of the urethral diameter measured by dilator bougies and maximum Urinary flux. Hinnan4 believes that the normal caliber should be 9F, and that dilation of this meatus should not alter the force of the flux, but its physical characteristics5.The obstruction of the female urethra can be classified with its localization or by the intensity of the histological lesion in the urethra (Fig.1). As follows we will discuss separately the ethiopathogenic aspects of treatment taking into consideration the different levels of obstruction in women.