Vesical Neck Reconstruction



Vesical Neck Reconstruction


JOHN C. POPE IV

JOHN H. MAKARI



Prior to toilet training, the functions of the lower urinary tract include storage of urine at low pressure and good emptying. The result is protection of the upper tract and avoidance of urinary tract infection. Adequate outflow resistance is not necessary during that time but is eventually critical to achieve urinary continence. Congenital anomalies resulting in inadequate outflow resistance, and thus failure to achieve urinary continence, can in general be divided into two groups based on pathophysiology. In the first group, there is an anatomic or developmental abnormality where the bladder outlet is malformed and incapable of providing adequate resistance. This group would include patients with bladder exstrophy, bilateral single ectopic ureters, persistent cloaca, and rarely an extensive ureterocele. In the second, more common, group involving neurogenic dysfunction, the outlet is normally developed from an anatomic standpoint, but abnormal neurologic control results in inadequate function.



INDICATIONS FOR SURGERY

If urinary continence is not achieved at an appropriate age in patients with congenital anomalies, and the patient has failed behavioral regimens such as timed voiding, all medical regimens, and other conservative therapies (e.g., intermittent catheterizations), then surgical intervention should be considered. The International Children’s Continence Society recommends that surgical treatment should be tailored to the individual patient, with consideration being given to patient age, history, urodynamic findings, and coexisting disabilities (1). It is critical to ensure that the bladder is a compliant storage reservoir prior to any reconstructive procedure on the lower urinary tract. Increasing outflow resistance in the presence of inadequate bladder capacity would put the patient at significant risk for upper tract deterioration and febrile urinary tract infection. Determining the commitment of the patient and family to achieve a good result with reconstructive surgery, including a willingness to perform intermittent catheterization if necessary, is critical.


SURGICAL OPTIONS

In few areas of reconstructive urology, there are as many choices to consider as for bladder neck repair and as little consensus as to which repair is appropriate for a given patient or setting. One reason for the variety of choices is the wide range of patients and problems for which the procedures are used. In some cases, the procedure to increase outflow resistance may logically be chosen based on particular patient considerations, but the experience and confidence of the surgeon with a given technique also may play a significant role in the choice.

Conceptually, techniques to increase outflow resistance may be considered as one of two general types. The first set of repairs is used to improve the function of the native outlet, while the second set is designed to repair the anatomy and functionally alter the outlet. Several procedures that may provide benefit and are occasionally used include urethral suspensions, injection of bulking agents, artificial sphincters, and obliteration of the bladder neck.

One of the first bladder neck repairs to function in such a manner was the urethral suspension described by Marshall-Marchetti-Krantz, which has since been modified by numerous surgeons. While these procedures have been successful in treating stress urinary incontinence among neurologically normal females, they have had minimal effect and are rarely indicated for pediatric patients with congenital anatomic anomalies of the outlet or neurogenic dysfunction.

Recently, transurethral injection of bulking agents has been tried to improve the function of the existing outlet. Initially, the use of polytetrafluoroethylene and later bovine collagen were reported. More recently, the availability of dextranomer/hyaluronic acid copolymer has renewed interest in injection therapy for increasing bladder outlet resistance and for correction of sphincteric incontinence. Injection therapy is relatively simple, avoids any incision, but has met with limited results for significant outlet anomalies (2). Further, the durability of this approach is a concern, as declining rates of dryness and/or improvement are observed even years after treatment (3). Injection therapy may, however, be useful after primary repairs in patients who have some persistent incontinence (3,4,5).

The most definitive procedure to improve the function of the outlet as it exists is placement of an artificial urinary sphincter. This group of procedures would seem appropriate for patients with a normal or near-normal outlet from an anatomic standpoint and to have little role for patients with significant anatomic anomalies such as bladder exstrophy or bilateral single ectopic ureters. Even with improved durability in newer models, the average life span of an artificial urinary sphincter is 8 years. Therefore, when placed in a pediatric setting, future revision surgery is inevitable (6).

The ultimate procedure to increase outlet resistance is division and closure of the bladder neck. Effective closure requires extensive mobilization of the bladder and bladder neck away from the urethra with interposition of omentum. It must be accompanied by construction of a continent abdominal wall stoma for bladder catheterization and effectively moves the reconstruction into the realm of continent urinary diversion.
Division of the bladder neck has in general been reserved for complex patients who have failed multiple prior procedures to effectively increase outflow resistance; however, it may be performed in select patients as primary definitive management. Extremely high success rates have been reported for both primary or secondary management when the above principles are followed (7).


SURGICAL TECHNIQUE


Fascial Sling for Bladder Neck Suspension

In adults, fascial slings may be performed transvaginally, and a small patch of fascia is secured with suspension sutures. In pediatric patients with congenital anomalies, fascial slings have in general been placed from above, often at the time of bladder augmentation. Before placement, the pelvic floor is cleared of overlying fatty tissue and a 2-cm incision made through the endopelvic fascia on either side of the bladder neck and proximal urethra (Fig. 96.1A). This area may be identified by palpation of a transurethral catheter and balloon seated at the bladder neck. Using blunt dissection, a plane is developed between the bladder neck and vagina in girls or rectum in boys (Fig. 96.1B). This plane may at times be more easily developed from the cul-de-sac by dissecting behind the bladder and ureters from above. With a difficult dissection, it may be useful to open the bladder, in particular if bladder augmentation is planned.






FIGURE 96.1 Pubovaginal sling. A: The endopelvic fascia is cleared of fatty tissue and a 2-cm incision made on either side of the urethra. A Foley catheter through the urethra may be palpated for identification of the urethra and bladder neck. B: The plane between the posterior urethra and anterior vagina is carefully developed using a right-angle clamp. C: A fascial strip 1 cm wide is passed through the anterior rectus fascia and rectus muscle lateral to the midline incision. It is secured on the left to the anterior fascia. The sling is then passed behind the bladder and will be brought through the right rectus muscle and fascia to be secured at the proper tension.

Once the proper plane is developed and the appropriate length of graft determined, a rectus abdominis fascial strip 1 cm in width and appropriate in length is harvested. The fascia may be taken in either a vertical or horizontal fashion depending on the initial incision. Fascia from other sites has been utilized but requires a second incision. Autologous cadaveric tissue or biodegradable scaffolds may also be used.

All of the grafts are in general brought through the rectus muscle and anterior rectus fascia on either side and approximated to the anterior rectus fascia using permanent sutures (Fig. 96.1C). If long enough, the two limbs of the sling may also be approximated to each other superficial to the fascia.

In patients with stress incontinence, the sling is placed tightly enough to maintain the proximal urethra and bladder neck in the appropriate anatomic position. Too snug of placement in such a setting may impede spontaneous voiding. When used for patients with neurogenic dysfunction who will not rely on spontaneous voiding, the sling may be pulled up more tightly to improve compression of the bladder neck and proximal urethra. If intermittent catheterization postoperatively will be performed through the native urethra, intraoperative catheterization should be repeated frequently to make sure the fascial sling is not placed so tight as to impede catheterization.


A commonly employed modification of the traditional suspensory sling, used by many reconstructive surgeons, is the wrap-around sling. In this modification, the sling material (fascial or other) is wrapped around the bladder neck completely prior to securing the free ends in the manner of a suspensory sling. The theoretic advantage of this approach is greater coaptation of the bladder neck tissue than with a traditional sling while preserving the ability to perform intermittent catheterization per urethra (8).


Young-Dees-Leadbetter Bladder Neck Repair

The Young-Dees-Leadbetter bladder neck repair is typically performed in the setting of exstrophy-epispadias complex in the modern staged repair of exstrophy and after epispadias repair. Ideally, it is performed when a patient’s bladder capacity under anesthesia by gravity cystography is at least 85 mL and when the patient can participate in a strict postoperative voiding program (9). After bladder exstrophy closure, the procedure is typically performed through a lower midline incision. For patients with epispadias who do not require augmentation, the reconstruction may be done through a Pfannenstiel incision.






FIGURE 96.2 Young-Dees bladder neck repair. A: The trigone mucosa is incised to leave a posterior, central strip of mucosa 15 mm wide. The triangles of mucosa on either side are excised. The ureters have previously been reimplanted in a more cephalad position. B: The central mucosa strip is tubularized using a running absorbable suture. C: The lateral trigone muscle flaps are closed in an overlapping fashion around the neourethra. D: After completion of the bladder and urethral closure, several pairs of suspension sutures secure the urethra and bladder to the underside of the intersymphyseal band and lower abdominal wall.

The anterior bladder is opened. This incision is carried as far distally into the proximal urethra as possible. Splitting of the intersymphyseal band with subsequent closure may allow closure and tapering of the proximal urethra. Virtually all exstrophy patients require antireflux surgery, and typically, the ureteral hiatus is initially quite low in the bladder. The ureters are mobilized and reimplanted into the bladder 3 to 4 cm more cephalad in location. Typically, the ureters are reimplanted with a cross-trigonal technique, although the tunnels may even be angled upward in a cephalad direction from the new hiatus. A 12- to 15-mm wide strip of mucosa is preserved in the posterior midline of the urethra and bladder trigone for reconstruction of the neourethra. Parallel incisions through mucosa are made on either side of this strip and the triangles of trigone mucosa on either side excised (Fig. 96.2A). Submucosal infiltration of dilute epinephrine in those two areas may aid in excision and decrease bleeding. The midline strip of mucosa and subsequent neourethra are typically made 4 to 6 cm long depending on how much proximal urethra is exposed and reconstructed. The midline strip is tubularized over an 8 Fr catheter using absorbable sutures to approximate the edges. This tubularization may be done with interrupted or running absorbable sutures but should be tension-free (Fig. 96.2B). Small purchases of the adjacent superficial muscle
of the trigone may be included with the mucosa for strength. The closure is easier to begin distally and finished cephalad. The lateral flaps of trigone muscle are then wrapped over the neourethra in an overlapping fashion. To do so without tension, the muscle must be incised transversely at the cephalad margin of the mucosal excision. One flap of muscle is wrapped over the neourethra and approximated to the underside of the other muscle flap using interrupted, absorbable mattress sutures. The second flap of muscle is then wrapped over the first and approximated to the outside of the muscle, again with absorbable sutures (Fig. 96.2C). A soft urethral catheter is left in place during healing but should be secured so as to avoid tension on the neourethra. Ureteral stents or catheters are often left in place because of potential edema. The bladder is closed in two layers.

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Apr 24, 2020 | Posted by in UROLOGY | Comments Off on Vesical Neck Reconstruction
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