Minimally Invasive Management of Urinary Reflux



Fig. 51.1.
International classification of vesicoureteral reflux (VUR). From Tullus K. Vesicoureteric reflux in children. Lancet. 2015;385(9965):371–9. Reprinted with permission from Elsevier Limited.





Exam


The child with reflux typically has a normal physical exam. Symptomatic patients have an exam concerning for cystitis or pyelonephritis. This includes lethargy or fussiness, abdominal tenderness, costovertebral angle, or suprapubic tenderness. The urine may be foul-smelling. The child often has a fever or, in rarer instances, high blood pressure if renal damage is present from long-standing disease.


Labs


Basic chemistry panel may reveal elevated creatinine or electrolyte abnormalities from chronic renal failure in severe cases. Complete blood count may reveal leukocytosis if an infection is present. Urinalysis demonstrates the presence of leukocytes and/or nitrites with microscopic evaluation revealing urine WBC, RBC, or bacteria. Urine culture should be obtained and may confirm infection.


Imaging


The gold standard diagnostic study for VUR is a voiding cystourethrogram (VCUG). After urethral catheterization, the bladder is passively filled with contrast agent. Fluoroscopy is used to assess for reflux during the filling phase and during the voiding phase when there is active bladder contraction. Several cycles of filling and voiding are sometimes needed to make the diagnosis as VUR may not occur with every void [14]. It is customary to delay obtaining a VCUG until the patient has had at least several days of antibiotics and is no longer febrile, for the simple reason that performing an invasive test on an acutely ill child serves only to further suffering. Typically, the VCUG is performed 1–2 weeks later [15] following recovery from the acute illness. The drawback to this method is that it can miss the diagnosis in individuals with transient VUR that might only manifest during UTI. In these children VUR may not be present in the uninfected bladder, but in the setting of cystitis, inflammation and edema can compromise the borderline valve mechanism at the UVJ. These children may have repeat episodes of pyelonephritis but test negative for reflux on VCUG during uninfected periods. Only then is VCUG during active infection considered.

Radionucleotide cystogram allows for imaging and detection of reflux without the need for urethral catheterization and additionally only requires 1 % the radiation exposure delivered by VCUG [16]. Contrast, usually Technetium Tc99, enters the bladder indirectly by renal excretion and is detected on scintigraphic gamma camera imaging. This study is prone to false-positive results due to contrast not originating from the bladder and misreading of contrast remaining in the ureter or renal pelvis as a sign of reflux. It also is a poor modality for grading the degree of reflux and particularly in diagnosing lower grades of reflux. Given its higher sensitivity as compared with contrast cystography, radionucleotide cystography is most useful to rule out presence of VUR and therefore is most commonly used in children with known history of reflux for follow-up and identification of reflux resolution.

Renal-bladder sonogram is excellent for the initial detection and grading of hydronephrosis. Hydroureteronephrosis in a child with an infection often suggests VUR though is nondiagnostic. Given that ultrasound is a benign testing modality in children, it is the test of choice for initial evaluation of the pediatric patient with symptomatic UTI but should not be considered a proxy for VCUG as it is rarely positive [17]. Renal sonography is also used by some during the follow-up of VUR patients to assess renal growth. In very experienced hands, abnormalities in corticomedullary differentiation and/or renal size are suggestive of renal dysplasia and long-standing reflux.

Nuclear renal scintigraphy is the gold standard for imaging functioning renal parenchyma and renal scar detection. The study is performed by using 99 m Tc-labeled DMSA, which is taken up only by functioning renal cortical tissue (proximal tubules). Renal cortical abnormalities are visualized on DMSA scans as areas of photopenia, and acute pyelonephritis (APN) is distinguished from renal scars based on the persistence of the renal contour or its absence suggesting the loss of cortical volume (scar). Thus, it is useful both in the diagnosis of APN and for long-term assessment of renal cortex health. In fact, DMSA scintigraphy has been found to be more accurate than sonography for the detection of APN [18].


Other Tests


Urodynamic evaluation allows for assessment of bladder functional status, including emptying characteristics. It is particularly valuable for the detection of whether the bladder outlet is functioning properly or whether there is presence of higher resistance during voiding which could lead to abnormally high bladder voiding pressure. These conditions may worsen existing urinary reflux or delay spontaneous resolution.


Surgical Indications


Both medical and surgical managements are geared toward reducing infections and preventing renal cortical scarring. Once reflux is diagnosed, patients are continued on daily low-dose prophylactic antibiotics with regular follow-up and imaging until the reflux resolves or is corrected surgically. Common practice has been to allow all grades of reflux ample time to resolve spontaneously while on suppressive antibiotics, with the understanding that this approach is less successful in high-grade reflux. Some have advocated immediate surgical repair when the likelihood of resolution is slight, such as with bilateral grade IV reflux or unilateral grade V reflux, but this author prefers to observe all children initially. Children with secondary reflux should first be offered a management strategy that includes addressing bladder overactivity with anticholinergics, constipation with laxatives or fiber supplements, and poor emptying with timed voiding or catheterization, as appropriate.

Surgical intervention is typically warranted after medical management has been unsuccessful. In children with recurrent pyelonephritis on antibiotic prophylaxis, including those with breakthrough infections with resistant organisms, medical noncompliance or intolerance, or persistence of reflux with renal scarring, surgical correction is usually advised. Decision to operate will also be dependent in certain circumstances on the sex of the child. As the prime age of post-pyelonephritic renal scarring occurs in children up to age 5, asymptomatic low-grade VUR has less clinical significance in the older child [19]. In boys older than 5 years who have persistent VUR though no prior UTIs on antibiotic prophylaxis, antibiotics may be discontinued, and the child may not need future formal follow-up. In girls, surgical intervention may be recommended to prevent complications associated with APN during future pregnancies, although that recommendation should be tempered by the child’s history of UTI and grade of VUR [20, 21]. Ultimately the decision to proceed to surgery and the type of surgical intervention to be undertaken will depend on many factors including the psychosocial needs of the child and family [22].



Technique: Laparoscopic and Robotic Surgery for Vesicoureteral Reflux



Extravesical Ureteral Reimplantation



Special Considerations


Laparoscopic and robotic-assisted laparoscopic surgery has been popularized in recent years with the primary goal of reducing perioperative morbidity associated with surgery while maintaining success rates. Laparoscopic correction of VUR using the Lich-Gregoir extravesical technique, the most commonly performed procedure for laparoscopic correction of reflux, was initially reported in 2000 [23]. With this technique, the bladder is approached from the retroperitoneum, and the distal ureter is dissected from the detrusor, leaving the ureteral orifice intact. Dissection of the detrusor is then carried out cephalad from the ureteral orifice to create a new submucosal tunnel. The ureter is positioned in the new tunnel, and the detrusor is re-approximated over the ureter. The technique has a steep learning curve. Another downside is potentially exposing the child to longer operative times [24, 25].

This same laparoscopic surgery is now done using robotic assistance, called robotic-assisted laparoscopic extravesical ureteral reimplantation (RALUR ) using the da Vinci® Surgical System [26]. The robotic surgical system has facilitated performance of laparoscopic surgery and has risen in popularity among pediatric urologists for its ease in dissection and intracorporeal suturing.


Anatomy


The distal ureter passes through a submucosal tunnel in the bladder wall prior to its entry into the bladder lumen at the trigone. With bladder filling, this portion of the ureter stretches, thins, and is compressed against the detrusor back wall, preventing reflux of urine into the upper tracts. Inadequate length of the intramural distal ureter or inadequacy of the detrusor back wall leads to an incompetent valve mechanism. This has been the basis for all surgical interventions performed for surgical correction of VUR. In healthy, non-refluxing ureters, the tunnel length to ureteral diameter is 5:1. For success in definitive reflux correction surgery, the minimum tunnel length to ureteral diameter ratio should be at least 3:1.


Positioning


The patient is placed supine with the lower extremities abducted and frog-legged. Rolls are placed under the bilateral knees to offset the pressure from external rotation of the hips. Older children may be placed in lithotomy. The abdomen, pelvis, and perineum are prepped. Often, a cystoscopy is first performed and bilateral ureteral stents placed. A Foley catheter is left in place. The patient is then repositioned to Trendelenburg for the duration of the surgery.


Instruments






  • Laparoscopic [23]:



    • 5-mm trocar


    • 3-mm working port x2


    • 5-mm working port


    • 5- to 3-mm reducer seal


    • 3- or 5-mm 0-degree laparoscope (or 30-degree)


    • 3-mm curved scissors


    • 3-mm tapered curved jaw dissectors x2


    • 5-mm Babcock forceps, ratcheted


    • 3-mm Allis grasper, ratcheted


    • 3- to 5-mm lap needle driver


    • Synthetic absorbable suture on a tapered needle




  • Robotic [24]:



    • da Vinci® Surgical System


    • 8.5-mm robotic port


    • 5-mm robotic ports x2


    • Hook electrocautery


    • Maryland grasper


    • Hot scissors


    • Needle driver


    • 4-0 Prolene® (polypropylene, Ethicon) suture


    • PDS® (polydioxanone, Ethicon) suture


    • 5-0 Monocryl® (poliglecaprone, Ethicon) suture


Steps


A 5-mm, 0-degree laparoscope is inserted through the umbilicus and pneumoperitoneum is achieved. Traditionally, three working ports have been placed under direct vision along the line of a Pfannenstiel incision at the middle and two ends. The middle port is usually 5-mm and the two end ports 3-mm (Fig. 51.2). The ureter is identified at the pelvic brim and followed down to the distal aspect. The overlying peritoneum is incised. The ureter is identified and grasped with Babcock forceps and freed from the surrounding tissue. Ureteral stents, if placed previously, would be removed at this point. A vessel loop or Diamond-Fox retractor can then be passed around the ureter.

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Fig. 51.2.
(a) Patient positioning for RALUR (not shown is robot docking between the legs). (b and c) Creation of detrusorrhaphy with closure. From Gundeti MS et al. Robot-assisted laparoscopic extravesical ureteral reimplantation: technique modifications contribute to optimized outcomes. Eur Urol. 2016. Epub ahead of print. Reprinted with permission from Elsevier Limited.

Next, the submucosal tunnel is developed. The direction of the tunnel is marked using electrocautery. A traction suture using 4-0 Prolene® is placed at the proximal end of the detrusor tunnel using a straight needle, and the needle is passed back externally through the abdominal wall. This suture can be manipulated externally to achieve the desired tension and elevation of the bladder. The incision of the tunnel is then performed in a proximal to distal manner. This dissection is carried down to but not violating the detrusor mucosa, using scissors rather than cautery to prevent injury to bladder innervation. Detrusor flaps are then created along this plane and elevated for a distance of approximately 4–5 cm. The ureter is placed in the tunnel, and a 5-0 Monocryl® suture is placed at the most proximal end and the detrusor is then closed (detrusorrhaphy) from distal to proximal starting at the ureteral orifice. A recent modification to this technique by Gundeti et al. includes a U-stitch of 5-0 PDS® incorporating the detrusor muscle and ureteral adventitia at the apex of the tunnel, followed by a continuous running suture, incorporating the ureteral adventitia in every other throw [27]. The traction suture is released, the bladder is filled, and the position of the ureter is reassessed. A catheter is left in the bladder for 12–24 h postoperatively.

In the robotic-assisted approach, the endoscope port at the umbilicus is placed with a 30-degree 12-mm scope. The two working ports are placed at the midclavicular line; in children <3 years old, placement is slightly above the umbilicus and in children 3 or older at the level of the umbilicus. The remainder steps in the surgery are the same.


Pearls/Pitfalls


The extravesical approach does not require cystotomy or ureteral anastomosis, thereby eliminating morbidity associated with these. Laparoscopic extravesical reimplant surgery, compared to the open extravesical approach, additionally allows for decreased hospital stay, reduced incisional pain, improved cosmesis, and decreased use of postoperative narcotics. Another benefit of the extravesical approach is that the child’s anatomy remains favorable for endoscopic instrumentation later in life should the child need ureteroscopy for stones or other indications.

While many studies have demonstrated feasibility and safety of the laparoscopic approach, the drawback of this approach continues to be long operative times and a steep learning curve [25]. Some challenges worth highlighting are difficulty with exposure of the ureter, trauma to the ureter, and difficulty developing the extravesical tunnel. Laparoscopic ureteral reimplantation, despite high success rates, failed to become widely adopted given the technical challenges [24] and did not show significantly decreased morbidity compared to the open technique [25, 28]. With the addition of the robotic-assisted technology, first described in 2004, there has been improved visualization and suturing techniques over the purely laparoscopic approach.

Another notable pitfall is postoperative urinary retention [24, 29]. In one study, there were no reported cases of postoperative urinary retention in a group of 41 patients, attributed to improved visualization and preservation of the neurovascular bundle lateral to the ureteral hiatus using the robotic-assisted technique [29]. Despite this, other studies have reported difficulty identifying these nerves [24] and that even as the nerves are identified and preserved, the incidence of retention was unchanged [30].

Additional reports both critical and supportive of widespread use of RALUR have acknowledged increased operative times, and subsequently increased cost, versus the open approach. Peters et al. reported that for bilateral ureteral reimplantation, the average time for the open approach was 210 min versus 262 min for RALUR. There has been, however, no finding of significant increased operative times when comparing robotic unilateral reimplantation to robotic bilateral reimplantation.


Postoperative Care (Extravesical)


Most children are kept in the hospital for one night after the surgery. Diet is started right away and advanced as tolerated. Intravenous fluids are kept on until the child demonstrates ability to tolerate oral intake sufficiently. The Foley catheter is removed the day after surgery and the child discharged once voiding spontaneously with a post void residual that is no more than half of the voided volume. The child then follows up in 1 month with an ultrasound.

In experienced hands, the robotic technique has offered similar success rates (reportedly 77–100 %) as the open technique [27]. In one study the success rate of RALUR (as defined by resolution of reflux) was 97.6 % [29], and in one single-surgeon study comparing RALUR to open intravesical ureteral reimplant, the success rate was 97 % versus 100 %, respectively [24]. Two separate reports, one by Schomburg et al. [31] and another by Casale et al. [29], even suggested postoperative VCUG could be avoided given the high success rates in their experience, though other reports by skilled surgeons warned against adopting this approach until a larger series is available to confirm success rates similar to the open technique [24, 25].

As it currently stands, there is insufficient evidence to suggest that RALUR is at a point where it is clearly a superior option to the open technique. Some experts have suggested it may be particularly advantageous in bilateral cases and in cases of older children who would benefit most from the improved pain control [25, 31].


Intravesical Ureteral Reimplantation



Special Considerations


Another minimally invasive technique for VUR correction is endoscopic intravesical (or “transvesical”) ureteral reimplantation. The approach was first described in 2005 using standard laparoscopic instruments and combines laparoscopic and endoscopic techniques. A robotic-assisted approach was described the same year by Peters and Woo [32]. This approach is unique in that it does not require transperitoneal access, relying instead on carbon dioxide insufflation of the bladder or pneumovesicum. It has been supported for its potential to reduce postoperative bladder spasms, reduced incisional pain, improved cosmesis, and earlier postoperative catheter removal compared to the standard open ureteral reimplantation technique. The major components of this surgery are dissection of the ureter, creation of the submucosal tunnel, and ureteral neocystostomy similar to open Cohen cross trigonal reimplantation. Robotic assistance has facilitated the delicate dissection and suturing required for this procedure and has improved overall efficiency.

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Oct 25, 2017 | Posted by in PEDIATRICS | Comments Off on Minimally Invasive Management of Urinary Reflux
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