Vesicoureteral Reflux



Vesicoureteral Reflux


MARK R. ZAONTZ

CHRISTOPHER J. LONG



Until the 1980s, the treatment for reflux was dominated by ureteral reimplantation, with cure rates approaching 98%. However, multicenter studies have since shown that not all reflux is created equally. Lower grades (I to II) of reflux have high spontaneous resolution rates, and these patients could be followed at least initially with observation or medical management with continuous low-dose prophylactic antibiotics and yearly reassessment. Higher grades of reflux (III to V) are associated with a higher incidence of renal scarring and lower rates of spontaneous resolution and warrant closer follow-up. These findings have led to a field change in management of vesicoureteral reflux (VUR).

Surgical correction of reflux has been shown to decrease the incidence of urinary tract infection (UTI) but may not prevent progression of reflux nephropathy when present. Reflux in the presence of sterile urine in general does not cause renal damage, although reflux in the presence of UTI and/or lower urinary tract obstruction can lead to renal scarring.

Boys, in general, present with higher reflux grades than girls of the same age and are more likely to develop a UTI, but boys also have a higher spontaneous resolution rate compared to girls. Studies showing that circumcised boys with low grades of reflux rarely get UTIs have led to a nonoperative algorithm in this group of patients. Circumcision can be offered to boys with reflux as a protective measure.

Reflux is commonly linked with voiding dysfunction in children. Screening assessment for any signs of abnormal voiding patterns (wetness, urgency, constipation, penile pain, dysuria, holding maneuvers) should be performed in all potty-trained children diagnosed with reflux. Recent evidence has shown high spontaneous cure rates for refluxing children when bladder bowel dysfunction is treated with urodynamics and biofeedback techniques. Conversely, children with significant voiding dysfunction have higher failure rates than those with normal bladder function, particularly when endoscopic bulking agents are used (1). While most cases of reflux are congenital in nature and considered primary reflux, increased intravesical pressure due to anatomic bladder outlet obstruction (posterior urethral valves) or functional causes such as neuropathic bladder/voiding dysfunction can lead to what is termed secondary reflux. Patients suspected of having secondary causes of VUR need further assessment prior to intervention.

Sampson (2) in the early 1900s proposed a flap-valve mechanism for the ureterovesical junction that was corroborated by Gruber (3), who found that those ureters with shorter intravesical segments were more prone to have reflux and therefore have a defective flap-valve mechanism. Stephens and Lenaghan (4) added that the deficiency of the intravesical ureter’s longitudinal muscle with or without a deficiency in ureteral tunnel length was also responsible for the reflux phenomenon. From a surgical perspective, we have learned that a 5:1 ratio of ureteral tunnel length to ureteral lumen diameter is necessary to prevent reflux. Care must be taken to mobilize the ureter such that the repair is not under tension, a straight trajectory through the bladder wall is maintained, that the ureter is sufficiently spatulated to prevent meatal stenosis, and that the blood supply is preserved throughout the dissection. Certainly meticulous technique is required to minimize trauma to the tissue. These guiding principles are fundamental to successful surgical correction of VUR.




INDICATIONS FOR SURGERY

Indications for surgical correction of VUR include the following:



  • Older patient with clinically significant reflux

    Breakthrough UTI

    Persistent high grade of reflux (III to V)

    Presence of renal scarring or decreased function

    Noncompliance with prophylaxis

    Family concerns for repeated invasive testing and long-term prophylaxis

Findings from the International Reflux Study in Children lend support toward surgical intervention in grade III and IV reflux, with the majority of these patients failing to resolve their reflux (11). Other studies have supported these findings, with rates of resolution of reflux ranging from 10% to 33% in patients with grade IV reflux (12,13). Surgery is in general recommended for grade V reflux because of the low likelihood of spontaneous resolution. Recurrent breakthrough urinary infection while on adequate antibiotic prophylaxis is the sine qua non for surgical intervention because otherwise these children are at high risk for recurrent pyelonephritis and renal damage.


ALTERNATIVE THERAPY

There are several factors that must be taken into consideration for appropriate management of VUR and should be individualized to the patient: reflux grade, degree of renal scarring, volume at onset of reflux, patient age, presence or absence of bladder outlet obstruction, compliance of the patient/family on prophylactic antibiotics, ability to remain infection-free while on prophylaxis, and presence/absence of associated bladder and bowel dysfunction. Reflux may spontaneously resolve, the majority of which occurs by 5 to 7 years of age. There is
an inverse relationship between reflux grade and likelihood of spontaneous resolution; the lower the grade of reflux and younger age of diagnosis, the higher the likelihood for spontaneous resolution. Boys are more likely to resolve than girls, and unilateral reflux is statistically more likely to resolve than bilateral reflux. Medical management consists of daily lowdose antibiotic prophylaxis, usually a sulfa-based compound or nitrofurantoin at bedtime. In addition to antibiotics, bladder training with biofeedback in cases of dysfunctional voiding is instituted. This is designed to improve bladder emptying at regular intervals, obviate bladder-sphincter dyssynergia, and maintain a minimal postvoid residual. This may require a variety of teaching aids and the use of pharmacotherapy such as anticholinergics and/or alpha antagonists. Equally important is to improve bowel function in the presence of constipation.


SURGICAL TECHNIQUE

Once the decision is made for surgical intervention, there are a myriad of operative procedures available depending on one’s preference and comfort level. The existing techniques are divided into endoscopic injection: the open approach via extravesical, intravesical, or a combination of the two; and the minimally invasive correction.


Endoscopic Surgery

Teflon was the first bulking agent used for endoscopic correction of reflux. Although the results were encouraging, later studies showed that there was migration of the Teflon particles to the lung, lymph nodes, and brain as well as the finding of granuloma formation; this resulted in the search for more biocompatible bulking agents (14). These have included both autologous agents (fat, blood, human collagen, bladder muscle cells, and ChondroGEL) and nonautologous agents (silicone, BioGlass, polyvinyl alcohol, and dextranomer microspheres). Deflux (dextranomer microspheres) has emerged as the agent of choice for bulking agents and at present is the sole agent approved by the U.S. Food and Drug Administration. Endoscopic surgery technique for reflux will be discussed in another chapter.


Extravesical Approach

Lich (15) and Gregoir (16) in the 1960s separately developed the extravesical approach to correct reflux. Further modifications of this approach have yielded success equal to that of the intravesical techniques (17). The benefits of this procedure are several: (a) The surgery is performed entirely outside of the bladder mucosa and as such avoids gross hematuria and irritable postoperative voiding problems such as urgency and bladder spasms, (b) catheter drainage of the bladder is brief, (c) wound drains are avoided, and (d) ureteral stents are eliminated. A further advantage of this technique is that hospital stay is brief, averaging 1.5 days in our hands, thus decreasing overall hospital costs.

The patient is placed in the supine position, and the bladder is catheterized on the field and filled to about one-third to onehalf of its estimated capacity with sterile saline. This facilitates dissection of the detrusor muscle from the mucosa. The bladder may be further filled or emptied throughout the procedure. The surgical procedure begins similarly to the intravesical approach with a Pfannenstiel incision. A Dennis-Browne retractor is then placed over moistened gauze pads, and the bladder is carefully mobilized and rotated anteromedially, exposing the perivesical space. Care should be taken to avoid entering the peritoneum during this maneuver. Placing an appropriate-sized Deaver retractor to help keep the rotated bladder in place will greatly facilitate locating the obliterated hypogastric vessel. This vessel is tied off with 3-0 polyglycolic acid suture, and the most lateral tie is tagged to help expose the ureter, which lies just beneath this vessel. In cases of bilateral detrusorrhaphy, the obliterated hypogastric vessel need not be tied off but simply recognized for ease of finding the underlying ureter. The detrusor innervation courses posteromedial to the ureter and care must be taken to limit dissection in this part of the bladder. This minimal dissection technique as described, as well as limiting the dissection of the extravesical submucosal tunnel, may help prevent significant denervation and avoid postoperative urinary retention. The ureter is carefully mobilized and encircled with a vessel loop (Fig. 92.2). The ureter is freed up to its entry point into the bladder. During this maneuver, the Deaver retractors may need to be reset to keep the ureter in the middle of the operative field. A tennis racket incision is made around the ureteral detrusor hiatus and deepened until the ureter is only attached to the mucosa. The detrusorotomy is then extended to create a 3- to 5-cm trough. It is helpful to place stay sutures of 3-0 polyglycolic acid on the detrusor edges to facilitate dissection of the detrusor muscle off the mucosa. All vessels encountered during this dissection are tied off with 4-0 or 3-0 polyglycolic acid suture, and great care is exercised to avoid making a rent in the bladder (Fig. 92.3). If this occurs, immediately close the defect with the 6-0 chromic catgut. The dissection should be generous enough to lay the ureter in the newly created trough and permit the detrusor muscle to be closed over the ureter without too much tension. To complete the detrusorotomy, dissection is extended toward the bladder neck beyond the distalmost detrusor incision to allow placement of the advancement sutures. The first limb of the two sutures is through the detrusor (outsidein), entering at the distal limit of the trigonal musculature and exiting in the plane between the mucosa and detrusor. The second limb of the suture is placed through the ureteral muscle, and the final limb of the suture is back through the detrusor (inside-out). Tying the pair of “vest- type” sutures advances the ureter on the trigone, creating a longer submucosal tunnel, and anchors the ureteral orifice distally, preventing proximal migration of the ureter (Fig. 92.4). The remaining detrusor defect is
closed over the ureter in two layers; the first is a running layer and the second is an interrupted Lembert suture, both using 4-0 polyglycolic acid suture. Care must be exercised to avoid making the ureteral hiatus too snug. The exit point for the ureter should be able to admit a hemostat between the detrusor and the ureter easily (Fig. 92.5). No perivesical drains or ureteral stents are used, and the Foley catheter is removed the following morning.

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Apr 24, 2020 | Posted by in UROLOGY | Comments Off on Vesicoureteral Reflux
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