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EXPANSIVE PROCEDURES
Different pathologies can cause mass effect in the urethra such as: hemangioma, prolapse of the mucous membrane, condyloma, polyps, periurethral cyst, adenoma, epithelial polyp and carcinomas8. These pathologies can cause obstructive symptoms, sometimes of intermittent characteristics, such as local pain, urethrorrhagia and hematuria8. The most common urethral lesion in women is the caruncle, in most cases it can make a protrusion through the meatus urinarius and this can cause obstructive symptoms8 (Fig.2). The estrogenic deficiency could be a possible cause for this pathology, which occurs in menopause, the treatment in symptomatic cases would be local estrogen therapy and anti-inflammatory and exceptionally surgical excision 9 . Among benign tumors of the urethra we observe leiomyomae, the hemangiomae and the fibroepithelioma10. It is believed that the fibroepitheliomas are resulting from chronic urethral irritation caused by undwelling mainly in paraplegic patient. The treatment in most cases is surgical exeresis, which may lead to secondary urethral stenosis8.
Primary carcinomas of the feminine urethra are rare, they can be treated with radiotherapy or surgical exeresis depending on histological type11. Garden11 noticed 40% of urethral stenosis after treatment with radiotherapy for a urethra scaly tumor.

SURGICAL POST TREATMENT
The most frequent cause of urethral stenosis and iatrogenic (Fig.3), resulting from surgical treatment of the genital prolapse or Urinary Incontinence, due to surgical hypercorrection12. In Marshall- Marchetti-Krantz’s surgery, urinary retention occurs in 5 to 20% of the cases7, 5 to 7% in urethropexy by needle13 and 2.8 to 25% in slings or retropubic urethropexy14,15. In spite of the better understanding of the physiopathology of urinary incontinence that allowed that the slings be done with no tension, diminishing considerably the cases of obstruction, these procedures are the ones that cause a larger degree of obstruction14. In these cases some authors preconize urethrolysis and the operation of Urinary Incontinence14.

HORMONAL DEFICIENCY
The urethra’s epithellum transforms itself due to estrogenic privation in menopause, causing the transformation of the epithellum from squamous to columnar, which characterizes senile urethritis16. In the vulvar dystrophy a urethral mucosa atrophy occurs due to a low hormonal level, causing a dryness of the urethra and then hypovascularization, leaving this sensitive to infections and traumas, which may cause a stenosis, generally meatus stenosis12 (Fig. 4), which treatment consist of hormonal reposition, urethral dilation or even meatotomy.

OTHER CAUSES
An obstruction at the level of the vesicle bladder may occur due to the inadequate opening of such, in Marion’s illness17. In these cases the urodynamic study reveals a detrusor pressure (Pdet) larger that 60 cm H 2O with corresponding maximum urinary flux lower that 15 ml/s17.
More rarely may occur a functional obstruction of the urethra due to hypertonia of the external urethral sphincter, in these cases an elevated pressure of the detrusor is noticed and a low maximum urinary flux, the urethral calibration is normal (22Fr)18. Noble19 in 1995 measured the thickness of the striated sphincter using transvaginal ultrasound in women with an obstruction, with the video urodynamic, in comparison with women with no obstruction, it was observed that in average the volume of the obstructed patient’s sphincter was of 3cm3 against 1.3cm3 but not obstructed. Meanwhile the author questions if this factor could be considered as a cause of obstruction in these women19. In selected cases where the patients have a competent bladder necks an internal urethrotomy is indicated, to avoid post treatment Urinary Incontinence18. In women submitted to internal urethrotomy a depression occurs in the maximum urethral profile, but with no alteration in pressure transmission, showing in these cases a lesion in the intrinsic mechanism of the urethral coaptation, not affecting the extrinsic mechanism of urinary incontinence20.