Chapter 35 COLPOCYSTOURETHROPEXY
Genuine stress urinary incontinence (SUI) is a specific entity directly related to an anatomic abnormality that results in impaired efficiency of the urethral sphincteric mechanism, allowing loss of urine with increased intra-abdominal pressure. Owing to recent advances in urodynamic studies and the appreciation of the pathophysiology of true SUI, the treatment of this problem has become better understood; consequently, the purpose of surgical repair and the means of achieving it can be clearly defined.
In pure SUI, the sphincteric mechanism, with its striated somatic component and its smooth sphincteric element, is essentially normal. It is loss of the normal anatomic position or normal anatomic support, or both, that weakens the functional efficiency of this sphincteric unit. Accordingly, restoration of normal position and support of the vesicourethral segment usually reestablishes normal sphincteric function.
From this basic principle, it is clear that a suprapubic approach is both more effective than an anterior vaginal repair and longer lasting in terms of restoring the position and support of the sphincteric unit. Trying to push the urethrovesical junction into a normal retropubic position from below is obviously less sound than achieving the same result from above. The latter is the logical approach for placing the urethra and the urethrovesical segment in a secure, well-supported, normal anatomic position.
Preoperative demonstration of the presence of the anatomic abnormality is essential to the evaluation of the patient, because, in the absence of any anatomic variance, there is no reason for a surgical repair primarily intended to restore normal anatomy and support.
A lateral cystogram obtained with a radiopaque, soft red Robinson catheter permits visualization of the vesicourethral segment and its anatomic relationships. Two exposures with the patient in the absolute lateral position, first relaxed and then with maximum straining (Figs. 35-1 and 35-2), will demonstrate the extent of mobility and thus the effectiveness of the support to the vesicourethral segment. This study permits evaluation of both the normal resting position and the extent of mobility. If the resting position is abnormal (lower than normal), if the mobility of the vesicourethral segment is excessive (Fig. 35-3), or if both conditions are present, the lateral cystogram will confirm the anatomic basis for the existing and clinically established fact of SUI. It must be emphasized that this cystographic study does not permit the diagnosis of SUI but demonstrates the presence of the basic anatomic abnormality responsible for genuine SUI.
Figure 35-1 Cystogram (two views) shows the relationship between the vesicourethral segment and the pubic bone in the relaxed state. The perpendicular line from the vesicourethral point over the long axis of the pubic bone meets the pubic bone opposite its lower third.
Figure 35-2 Lateral cystogram shows the patient in the relaxed state (left), then straining (right). Note the extent of mobility of the vesicourethral segment in relation to any bony point. Normally, movement is less than 1.5 cm in any direction.
Figure 35-3 Lateral cystourethrogram of a patient with urinary stress incontinence, in the relaxed position (A) and with straining (B). Note the excessive drop of the vesicourethral segment and an increase in intra-abdominal pressure associated with straining. This is the classic anatomic abnormality of urinary stress incontinence.
Surgical repair should attempt to restore normal position and support without compression or obstruction. SUI is encountered frequently in multiparous women after middle age as a result of pelvic floor weakness, which might have begun earlier in life but has progressed and become manifest. As mentioned earlier, the intrinsic sphincteric mechanism is essentially normal. However, because of the laxity of the pelvic floor and the weakness of the normal mechanism of support to the vesicourethral segment, the latter tends to lie abnormally low and exhibits excessive mobility with increased intra-abdominal pressure (see Fig. 35-3) or with assumption of the upright position. The intrinsic sphincteric mechanism can be restored to normal function once this anatomic abnormality is corrected, without any need to plicate, constrict, or otherwise directly interfere with the sphincteric unit itself.
It is imperative to avoid the creation of any obstruction or damage to the delicate intrinsic sphincteric muscular element. If this principle is adhered to, the sphincter will regain and maintain its effectiveness, and the repair will be permanent. In my opinion, the suprapubic approach is the best way to achieve this goal.
The patient is supine, with the lower limbs stretched and supported in a slightly abducted position. The footpiece of the operating table is dropped down to permit easy access to the vagina, which is properly prepared and draped into the sterile field. A 22- or 24-Fr 5-mL Foley catheter is passed and kept in the sterile field.
The retropubic space is exposed through a suprapubic transverse or midline incision. In making this incision, one should stay close to the back of the pubic bone, dropping the anterior bladder wall, the urethra (easily palpated with the Foley catheter in place), and the anterior vaginal wall downward. This step is easy in patients who have had no previous surgical intervention in this area but is otherwise extremely difficult, and it is of critical importance. In the latter situation, adhesions are usually dense, and the anterior bladder wall frequently is found displaced downward and adherent to the back of the pubic bone. Unless the anterior bladder wall is freed and pulled upward, it will not be possible to expose the urethra and the urethrovesical junction.
Once the retropubic space is entered and the urethra is dropped downward with the anterior vaginal wall, no dissection should be done in the midline over the urethra. Whatever amount of tissue is covering it should be left undisturbed. In this way, the delicate musculature of the urethra is protected from any possibility of surgical trauma. Attention should be directed to the anterior vaginal wall on each side of the urethra—again, easily identified with the catheter in it. Most of the overlying fat should be dissected and cleared away to permit future firm adherence to any tissue brought into contact with it. This area is extremely vascular because it has a rich, thin-walled venous plexus which should be avoided as much as possible. As this region is cleared, the vesicourethral junction becomes more apparent. This step can be facilitated by palpating the Foley balloon or, even better, by partially distending the bladder and defining the rounded lower margin of the anterior bladder wall as it meets the anterior vaginal wall. No dissection should be done at the vesicourethral junction itself, because at that point all the detrusor muscle fibers are moving downward to encircle the urethra, and every effort should be made to protect them from trauma. More laterally, however, the inferior margin of the bladder is identified and mobilized upward. The extent of this mobilization depends on the extent of downward displacement, and on occasion very little is needed. Placing fingers in the vagina facilitates this dissection and also is essential to determine the extent of the needed mobilization and freeing of the anterior vaginal wall.
The dissection in repeat cases is most difficult, particularly if three or four previous attempts at repair have failed. Nevertheless, it is in such circumstances that the dissection must be impeccable if good results are to be achieved. Unless the urethrovaginal wall is adequately exposed, all adhesions are severed, and the lower margin of the bladder, together with the vesicourethral junction, is permitted to slide upward, proper positioning and support will not be obtained. Utmost care must be taken not to lacerate or damage the urethral or vesical musculature. If identification of the lower margin of the bladder is difficult, one should open the bladder and, with a finger inside the cavity, define its limits for easier dissection and mobilization.