Pneumovesicoscopic Ureteral Reimplantation

Vesicoureteral reflux (VUR) is one of the most common urological problems in infants and young children, resulting from an incompetent ureterovesical junction (UVJ) that allows abnormal retrograde flow of urine from the bladder to the upper urinary tract. Several studies have reported an incidence between 0.4% and 1.8%. VUR predisposes to urinary tract infections (UTIs) and can lead to potential problems including renal scarring, loss of renal function, end-stage renal failure, negative effects on somatic growth, and risk for further UTIs.

VUR can be primary or secondary. Primary VUR is most commonly associated with a dysfunctional interaction between the ureteric bud and the metanephric mesenchyme. Nonsyndromic primary VUR is genetically heterogeneous and related to a locus on chromosome 1. There is a familial association seen in 30% to 35% of siblings and in one-third of newborns from parents who also had the condition. Secondary VUR refers to reflux associated with underlying abnormal bladder dynamics, voiding dysfunctions, and a neurogenic bladder.

Based on the degree of reflux into the ureters and kidneys, VUR has been classified into five grades according to the International Reflux Study Grading System: grade I—reflux into the ureter only; grade II—reflux into the ureter and nondilated pelvis; grade III—reflux with a mildly dilated pelvis; grade IV—reflux with moderate dilated calyces; and grade V—gross dilation of the ureter and blunting of all calyces ( Fig. 29-1 ).

Fig. 29-1

International Reflux Study Grading System: grades I through V A, Grade 1: reflux into the ureter only. B , Grade 2: reflux into a nondilated pelvis. C, Grade 3: reflux into a mildly dilated pelvis. D, Grade 4: reflux into dilated calyces. E, Grade 5: reflux into very dilated pelvis and blunting of all calyces.

Adapted from Palmer LS: Abnormalities of the bladder. In Palmer JS (ed): Pediatric Urology-A General Urologist’s Guide. Humana Press; pp 26-27, 2011, with permission for reuse.

The primary aim in the treatment of VUR is preservation of renal function and prevention of pyelonephritis. Management of grade I and II with nondilated ureters is usually conservative as the VUR often resolves spontaneously without active treatment. For grade III to grade V, the American Urology Association guidelines recommend continuous antibiotic prophylaxis as initial management. 15 Several studies have shown spontaneous recovery in 70% to 85% of grade I and II VUR and in around 50% in grade III VUR.

Surgical correction of VUR is indicated when conservative treatment with continuous antibiotic prophylaxis fails. Indications for antireflux surgery include breakthrough urinary infections while on continuous antibiotic prophylaxis, persistent dilating reflux, worsening of renal scarring, bilateral grades IV to V VUR and persistent reflux beyond 4 years of age, and various anatomic anomalies like a paraureteric diverticulum, obstructive and refluxing megaureters, and so forth. For those with unilateral VUR on voiding cystourethrogram (VCUG), intervention for the contralateral side should be considered when there is kidney scarring on the dimercaptosuccinic acid (DMSA) scan, a cystoscopically abnormal contralateral ureteral orifice, or evidence of bilateral VUR on a voiding cystourethrogram. Any underlying bladder dysfunction should be excluded and, if present, should always be treated prior to operative intervention. Approaches to intervention are varied and range from endoscopic injection at the ureterovesical junction to operative correction. Operative correction of VUR can be achieved using various minimally invasive surgical (MIS) techniques. These include cystoscopic subureteral injection and endoscopic ureteral reimplantation by either an intravesical or an extravesical approach. Ureteral reimplantation is usually reserved for patients with high-grade reflux, failure of previous endoscopic corrections, and, especially, in complicated cases, associated anatomical anomalies.

Endoscopic Injection of Bulking Agents

Endoscopic therapy by injection of a bulking agent is an appealing option as it is minimally invasive and can be performed as a day surgery procedure, with minimal complications and a relatively short learning curve for the surgeon. The principle of the technique is to create a solid support behind the intravesical ureter at the level of the ureteral orifice to elongate the intramural ureter. Several bulking agents have been used for many years. Two popular ones include polydimethylsiloxane (PDMS, Macroplastique) and dextranomer/hyaluronic acid (Dx/HA, Deflux). Deflux was approved by the U.S. Food and Drug Administration (FDA) in 2001 and has been widely used. Recently, two new bulking agents have been introduced: polyacrylate-polyalcohol copolymer (PPC, Vantris) and polyacrylamide hydrogel (PAHG, Bulkamid). The complication rate for endoscopic injection of a bulking agent is low in general. However, mild hematuria can occur intraoperatively at the injection site. There is also a chance that the injected bulking agent may migrate and result in the late recurrence of reflux. In addition, there is a possibility of the bulking agent becoming calcified, which could lead to hematuria, intermittent back pain, and/or bladder mucosal injury.

Ureteral Reimplantation

Correction of VUR by ureteral reimplantation is usually reserved for high-grade reflux, for failure of previous endoscopic corrections, and in complicated cases. Although open operative reimplantation has remained the benchmark in the surgical correction of VUR, recent studies have shown that ureteral reimplantation using either laparoscopic or robotic techniques can achieve similar success rates when compared to the conventional open technique. Operative approaches can be classified into extravesical, intravesical, or a combination of these two.

The Lich and Gregoir procedure is a widely utilized technique for the extravesical approach for ureteral reimplantation. It involves ureteral hiatal recession by extramucosal tunneling of the ureter into the detrusor muscle. However, this procedure necessitates transgression of the peritoneal cavity. In addition, this technique necessitates dissection and intracorporeal suturing in a confined space, which can be technically challenging in a young patient with a small pelvis. However, an advantage of this method is prevention of bladder spasms, which can be debilitating at times to patients after an open intravesical procedure. This approach has not gained universal acceptance, likely due to these possible postoperative complications. Also, children with bilateral reflux have been shown to develop voiding dysfunction and urinary retention.

In contrast, the Cohen cross-trigonal ureteral reimplantation is a time-tested, open intravesical technique for reflux correction. It entails intravesical mobilization of the refluxing ureter with maintenance of the original ureteral insertion hiatus into the bladder wall, and the ureter is reimplanted across the trigone via a submucosal tunnel toward the contralateral ureter. However, the conventional Cohen technique involves an open vesicotomy with retraction of the bladder wall, and postoperative urinary diversion with bladder catheterization. This can lead to severe bladder spasms resulting in significant postoperative pain and discomfort, which can lead to an extended hospital stay due to the need for analgesics.

Ureteral Reimplantation Under Carbon Dioxide Pneumovesicum

This is a minimally invasive modification of the open technique. 11-13 Similar to the concept of pneumoperitoneum in laparoscopy, carbon dioxide (CO 2 ) is used to insufflate the bladder at a pressure of 10 to 12 mm Hg to create a working space inside the bladder that can allow various intravesical procedures, including a Cohen type of cross-trigonal ureteral reimplantation, to be conducted endoscopically using standard laparoscopic instruments.

Preoperative Preparation

An enema is administered prior to the operation for bowel cleansing. The patient is prepared with general anesthesia with endotracheal intubation and muscle relaxants to allow adequate bladder insufflation with sufficient intravesical operative space during the procedure. On induction of anesthesia, a broad-spectrum antibiotic is given intravenously. Use of nitrous oxide is avoided as it will distend the bowel.

Operative Technique

The patient is positioned in a supine and slightly Trendelenburg position at the end of the operating table. The legs are separated so the surgeon can gain access to the perineum and urethral orifice for intraoperative cystoscopy and bladder catherization. For small infants, the surgeon stands above the infant’s head. In older children, the surgeon stands to the patient’s left side so that he or she can use his or her right hand for dissection and suturing ( Fig. 29-2 ). The video monitor is positioned at the foot of the patient.

Apr 3, 2021 | Posted by in GASTOINESTINAL SURGERY | Comments Off on Pneumovesicoscopic Ureteral Reimplantation

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