The diagnosis of female lower urinary tract obstruction (FLUTO) is elusive. It occurs in 2.7% to 8% of women presenting with lower urinary tract symptoms (LUTS), and may be caused by both anatomical and functional conditions. Anatomical causes of FLUTO includes intrinsic causes such as urethral stricture, periurethral diverticulum, vesicovaginal fistula, and urethral tumors; extrinsic causes such as incontinence surgery, periurethral fibrosis, periurethral cyst, fibroids and anterior vaginal wall lesions; and positional causes such as angulation due to pelvic organ prolapse.
Female urethral stricture (FUS), like other anatomical causes, restricts the maximum radius that the urethra can reach at the peak of its relaxation, increasing resistance to voiding flow. This may result in a reduced flow, augmented detrusor pressure during emptying, or both. FUS occurs in 4-13% of cases, which is equivalent to 0.1-1% of all patients with LUTS. Reports have shown a median age of onset of 50 years, being caused by either idiopathic factors (49-51%), iatrogenic factors (33-36%), inflammatory or infectious factors (8%), and trauma or straddle injury (7-15%).
There is currently no consensus on the definition of FUS and the diagnosis should be multimodal. Available diagnostic tools include urethral calibration, retrograde and/or antegrade (through cystostomy tract) evaluation with flexible cystoscope or semi-rigid ureteroscope, voiding cystography, post void residual volume, uroflowmetry and, in some cases, urodynamics.
The clinical  symptoms of FUS include a weak stream, a sensation of poor voiding, recurrent urinary tract infections, urethral pain, urinary incontinence, urinary retention or elevated postvoid residual, among others. In the terminal stages of FUS, secondary claudication of bladder contractility and accommodation may occur, which is usually irreversible.

The most common treatment for FUS is urethral dilatation (UD), which has shown success rates of only 43-49% in the long term (75.1% as first treatment and only 26.6% in those with one or more previous UDs).
Female urethroplasty, on the other hand, has accumulated consistently favorable experience over the last decade. For involvement of the most distal centimeter only, an advancement meatoplasty can be performed, resecting the narrowed segment. For all other cases, enlargement urethroplasty has shown long-term success rates between 92% and 88-95%, either with flaps or grafts, respectively.  Our group has opted for the dorsal onlay with buccal mucosa graft urethroplasty (DO-BMGU) technique.

The aim of this abstract is to characterize the demographic, clinical and perioperative variables and to analyze the medium-term outcomes of our series of female urethroplasty procedures performed with DO-BMGU.

This is an observational, case series study that prospectively recruited all cases of FUS diagnosed between 2016 and 2023, who later underwent DO-BMGU in a  tertiary care center. Demographics, comorbidities, baseline urinary symptom score and quality of life (IPSS-AUA) were recorded in all patients with suspected FUS. A minimum postoperative follow-up of 3-months was considered as inclusion criteria. Ultimately, 23 out of 25 DO-BMGUs performed, were included in the analysis as they met the aforementioned criteria.
In these cases a multimodal study was performed, using at least one of the following: cystourethroscopy, urethrocystography, urethral calibration, uroflowmetry/PVR and urodynamics for doubtful cases. In those patients with urinary retention using cystostomy or intermittent catheterisation, a peak flow (Qmax) of 1 ml/sec was assigned for mathematical calculations.
Once FUS was confirmed, all underwent a standardized DO-BMGU technique, which included a suprameatal inverted U-shaped approach, longitudinal dorsal urethrotomy from the meatus to the bladder neck, harvesting of a 4x2 cm inner cheek mucosal graft (without donor site closure) and fixation of the graft with absorbable stitches to the native urethral mucosa and paraurethral tissues. Intra- and perioperative outcomes were recorded: length and urethral segments involved, surgical operative time, estimated bleeding, days of hospitalization, days of urethral catheterisation and Clavien-Dindo classification of surgical complications. 
Regarding postoperative outcomes, for the first 3 months, patients had ready access to spontaneous reporting of any deterioration in their symptoms or stream caliber, which was supplemented with uroflowmetry/PVR. In the absence of spontaneous reporting, after 3 months, patients responded to the IPSS-AUA and underwent uroflowmetry/PVR. IPSS-AUA and uroflowmetry/PVR were repeated at the time of suspected recurrence or at 12 months.

Informed consent was obtained following the local protocols.

Twenty-three patients underwent DO-BMG with a mean age of 58.4 years old. Almost half of the patients (47.8%) present an idiopathic etiology, then 30% (7/23) present a FUS after a gynecological surgery. Sixty one percent (14/23) of the patients presented preoperative urinary retention at some point. Table 1.

The median surgical operative time was 150 min and median blood loss was 80 ml. The mean stricture length was 2.6 cm. Proximal-and-mid urethra was the most frequent location, in 30% (7 of 23 patients) of the cases. One way or another mid urethra was involved in 18/23 patients. After the DO- BMGU, median length of stay was 2 days, urethral catheter was removed in a median of 15 days. Overall complications presented in 4 patients, but none of the patients had a Clavien-Dindo >II grade. The median follow up time was 15 months, with stricture recurrence in two patients (9%). One patient presented with de novo stress urinary incontinence (4%).

Preoperative median of the IPSS-AUA scale was 29, while the postoperative was 8.5, which represents a variation of -20 points on the IPSS-AUA scale. 
On the IPSS-AUA Quality of Life, the median score before surgery was 6 (“to be terrible”), and the median score after surgery was 1.5, (“to be mostly satisfied”). This is a difference of -4 points. Table 2 shows the evaluation of pre- and post-operative voiding outcome measures.

This study has several strengths: (a) to our knowledge, it is the largest series of female urethroplasty in Latin America to date; (b) our results are consistent with the 80-90% medium-term success rate shown in previous studies, with mild and rare complications and only one case of de novo IOE; (c) only the DO-BMGU technique is included, which facilitates its interpretation; d) Patients were evaluated pre- and postoperatively with simple, widely available tests and questionnaires, allowing longitudinal analysis and reasonable follow-up, considering that recurrences usually occur before 14 months; e) DO-BMGU can be used regardless of the presence of lichen sclerosus, radiation or vaginal lesions.
As for the limitations of the study, we can mention: a) it is still a small number of cases; b) there is no control group, which limits the interpretation of the results; c) although our follow-up is "reasonable", the ideal would probably be around >24 months (based on the available evidence on male urethroplasty); d) as no flaps or ventral approaches were used, it is not possible to question our theory regarding the preservation of urinary continence; e) there was no a priori calculation of the sample size.

The results are similar to those reported in the vast majority of studies of DO-BMGU and do not differ significantly from those using alternative techniques (ventral approach, use of vaginal flaps or grafts). 
We present objective and subjective data showing a highly successful procedure, which is justified by the very low rates of de novo incontinence and overall complications. We hypothesise that continence is maintained by preserving the urethral support structures, i.e. the pubourethral and urethropelvic ligaments, together with the anterior vaginal wall.
Our data support the reproducibility of this technique in a Latin American setting.