Hypothesis / aims of study
Reconstructive procedures aim to restore functional and morphological changes. The relationship between the degree of anatomical correction and functional outcomes
continues to be a challenging quandary in urological reconstructive surgery.
Stress urinary incontinence exemplifies the relationship between the change in morphology and the subsequent change in function.
Bladder neck repositioning procedures (BNRPs) provide a surgical option in treating female patients with urodynamic stress urinary incontinence. BNRPs include open Burch colposuspension, laparoscopic colposuspension and Vagino-obturator shelf procedure.
BNRPs address the anatomical and functional abnormality of urethral hypermobility. The surgical principle of elevating and repositioning the bladder neck to a higher intrapelvic position optimises the pressure transmission during raised intra-abdominal pressure caused by physical activity, thereby preventing stress urinary incontinence, the hypothesis proposed by Einhorning (1).
Previous studies have proved the success of colposuspension in achieving bladder neck elevation (BNE), as seen by the comparative assessment of pre and post-operative MRI scans of the pelvic floor of women undergoing colposuspension (2). Pre and post-operative studies have confirmed that colposuspension reduces bladder neck mobility and restores effective pressure transmission to the proximal urethra (3). Excessive BNE is associated with a significant incidence of voiding dysfunction and de novo detrusor overactivity.
The need for an optimal level of BNE consistent with a successful outcome while minimising post-operative voiding dysfunction and de novo bladder overactivity has been recognised. There are no simple methods that can be employed to quantify the extent of bladder neck elevation achieved during BNRPs. As a corollary, it has not been possible to determine the optimum level of BNE that maximises success and minimises morbidity.
The authors hypothesise that determining the optimum degree of BNE during bladder neck repositioning procedures would impact the quality of colposuspension and minimise post-operative voiding dysfunction.
We also hypothesise that the potential increase in the length of the urethra might reduce the cross-sectional diameter and improve the “mucosal seal” function of the urethra.
The study aims to determine the feasibility of using a catheter that can be marked to measure the degree of BNE and apply the technique as a starting point for further research that could shed light on this current knowledge gap.
The bladder neck is intimately attached to the anterior vaginal wall and is elevated along with it when suspending sutures are placed between the anterolateral vaginal wall and the iliopectineal ligament during colposuspension and the obturator internus fascia in vagino-obturator shelf procedure. The elevated bladder neck, in turn, pulls the catheter balloon resting upon it to a higher position; this causes the stem of the urethral catheter to be drawn into the urethra. The extent of movement of the stem of the catheter corresponds to the extent of BNE, which can be measured.
The authors describe a novel technique that enables precise measurement of the extent of bladder neck elevation achieved while performing open colposuspension. The technique has been utilised in three consecutive patients undergoing open colposuspension.
Study design, materials and methods
The operative steps of colposuspension are well standardised. However, the critical step of repositioning the bladder neck to a higher retropubic position is not standardised and remains subjective. The described technique makes it possible to measure the extent of BNE achieved objectively.
With the patient in the Lloyd Davies position, a Foley catheter is introduced into the bladder and the balloon inflated. The catheter is gently tugged down to ensure that the balloon rests on the bladder neck. A Vicryl tie is tied around the stem of the catheter at the level of the external urethral orifice. While elevating the anterolateral vaginal wall during suture placement and subsequent tying, it was observed that the stem of the catheter, along with the marker tie, is drawn into the urethra. Once the colposuspension sutures are tied, another Vicryl tie is tied around the stem of the catheter at the level of the external urethral orifice.
The marked catheter is removed at the end of the procedure and replaced with a new catheter for postoperative drainage.
The catheter with the Vicryl ties is examined to quantify the extent of BNE achieved. The measured distance between the base of the catheter balloon and the first marker tie denotes the initial length of the urethra. The distance between the two marker ties quantifies the extent of BNE achieved (Figure).
Interpretation of results
The technique demonstrated the feasibility to consistently measure the extent of BNE obtained by colposuspension intraoperatively and is potentially applicable to the alternative procedures that attempt to reposition the bladder neck. Furthermore, it has demonstrated a previously unknown factor that colposuspension produces a measurable increase in the anatomical length of the urethra. Previous studies have shown that the anatomical urethral length in women has a statistically significant correlation with the urodynamic parameters of Functional Urethral Length, the Length of Continence Zone, Valsalva Leak Point Pressure, Cough Leak Point Pressure and Maximum Urethral Closure Pressure and remains a valuable adjunct in the evaluation of women presenting with stress urinary incontinence.
The novel technique has several potential applications. It can be used in a large cohort of patients undergoing bladder neck repositioning surgery, and the results correlated with surgical outcomes to determine the optimal extent of BNE that is compatible with success while minimising post-operative voiding dysfunction.
The technique brings an element of objectivity to BNRPs and could be a helpful teaching tool during urological training. If further research clarifies the ideal level of bladder neck elevation compatible with successful outcomes, then the technique could be modified to achieve the same by using a calibrated urethral catheter during the surgical procedures.
The technique could be used in the routine assessment of women with stress urinary incontinence to determine the presence and the extent of urethral hypermobility. Currently, these are assessed subjectively by per vaginal examination. The previously described Q-tip test has not been incorporated into clinical practice due to patient discomfort and inconsistent results.
Patients with recurrent incontinence following previous bladder neck repositioning surgery can be assessed by this technique to determine if the failure of colposuspension is due to recurrence of urethral hypermobility due to the unravelling of the fixation sutures or alternative reasons, including intrinsic sphincter deficiency. The measured urethra length in such patients might revert to the pre-operative status if the cause of recurrent incontinence is the former.