Keywords

1 Introduction

1.1 Background

Vesicoureteral reflux (VUR) is a condition with anatomic and/or functional etiology that causes backflow of urine into the upper urinary tract. It is one of the most commonly diagnosed congenital anomalies of the kidney and urinary tract (CAKUT) among children presented with first febrile urinary tract infection (UTI) (Vachvanichsanong et al. 2017). The actual prevalence of the condition is unknown (Tekgul et al. 2017); however, estimated to be affecting 1–3% of infants and children.

Severe form of this condition causes recurrent pyelonephritis and renal scarring, which eventually lead to long term sequale of renal failure. Depending on the severity of VUR, management is catered according to individual patient condition (Arlen and Cooper 2015). Management options include, conservative close monitoring and continuous antibiotics prophylaxis, endoscopic bulking agent injection, minimally invasive procedures of ureteral reimplant using laparoscopic with or without robotic assistance to invasive open surgical approaches (Tekgul et al. 2017; Kim et al. 2017; Peters et al. 2010).

1.2 Scope

The scope of this chapter is confined to present the literature on minimally invasive approach of ureteral reimplant in children with VUR. Specifically to discuss the history, current status, consideration on the approach and future direction with highlights on Asian setting. For procedural description and technical details, recent publications and video bank are recommended as citations but not illustrated in this chapter (Patel and Ramalingam 2017; Dangle et al. 2014; Diaz et al. 2014; Schober and Jayanthi 2015; Weiss and Shukla 2015; Gundeti et al. 2016). Source of literature reference for this chapter was acquired from Pubmed on November 2017 with restriction only for human studies. (Search term strategy in Appendix A.)

2 History of Minimally Invasive Ureteral Reimplant in Management of Vesicoureteral Reflux Among Children

The conventional open approach of ureteral reimplantation of various techniques has shown high success rate ranging 92–98.3% in the treatment of VUR among children (Kennelly et al. 1995; Heidenreich et al. 2004; Austin and Cooper 2004). With the introduction of minimally invasive approach, laparoscopy was utilized in the early 1990s reported initially on animal model with extravesical technique (Atala et al. 1993; Schimberg et al. 1994; McDougall et al. 1995). Subsequent reports on human series, initially on adult patient, later on pediatric series were then published within the same decade (Reddy and Evans 1994; Ehrlich et al. 1994; Janetschek et al. 1995). The feasibility of the laparoscopic extravesical ureteral reimplant procedure was then established; however, due to the initial experience of technical challenges and time demanding, the approach was not immediately adopted by many (Smaldone et al. 2007). With learning curve being traversed, availability of better laparoscopic equipments and technical modifications, better successful clinical outcomes of the minimally invasive approach had been reported; yet careful selection of suitable patient was strongly recommended to achieve good outcome (Lakshmanan and Fung 2000; Carswell et al. 2003; Shu et al. 2004). Within the parallel timeframe, the adaptation and modification of laparoscopic extravesical ureteral reimplant were being reported in Asian countries with later showing comparable clinical outcomes (Kawauchi et al. 2003; Sakamoto et al. 2003; Ansari et al. 2006; Simforoosh et al. 2007).

In the initial exploration of minimally invasive approach ureteral reimplant, the endovesical approach utilizing both endoscope and laparoscopic instruments, was also reported in Asia (Okamura et al. 1993, 1996, 1999); however, due to limitation of visibility and mobility in using the urethral endoscope, technical difficulty of transvesical port placement and lower success rate (62.5–86%) compared to open approach; this approach was not favoured and became unpopular (Cartwright et al. 1996; Gatti et al. 1999; Gill et al. 2001; Tsuji et al. 2003; El-Ghoneimi 2003). Further animal studies were then performed to explore the feasibility of carbon dioxide insufflations of the bladder modifying the intravesical approach to improve visibility and technical mobility (Lakshmanan et al. 1999; Olsen et al. 2003). Subsequent reports in human series were published from Asian countries as well as north American experience with comparable success rate (91–96%) to open approaches (Yeung et al. 2005; Kutikov et al. 2006; Canon et al. 2007; Schober and Jayanthi 2015; Soulier et al. 2017). To overcome the limited dexterity, 2D spatial image and steep learning curve of pure laparoscopy, robotic system was introduced in 2000 to assist laparoscopic procedure, which gained high popularity for pelvic surgery procedures (Finkelstein et al. 2010). Robotic assisted laparoscopic was then being adapted for ureteral reimplants in children with initial experience reported in the early 2000 (Peters 2004; Peters and Woo 2005; Hayn et al. 2008).

3 Current Status of Minimally Invasive Approach of Ureteral Reimplant in Children

3.1 Current Status of Laparoscopic Ureteral Reimplants in Asian Countries

In the past decade, numerous successful intermediate to long term outcome were being reported from the Asian countries for pure laparoscopic ureteral reimplant of both extravesical and intravesical approach with some modifications (Tsai et al. 2008; Chung et al. 2008; Kawauchi et al. 2009; Chan et al. 2010; Hong et al. 2011; Chung et al. 2012; Emir et al. 2012; Moritoki et al. 2012; Bi and Sun 2012; Hayashi et al. 2014; Kim et al. 2015; Javali et al. 2015; Soh et al. 2015; Lau et al. 2017) The reported success rate ranges from 90% to 100% with low number of complications (Table 17.1). Some Asian studies also showed an improving perioperative and long term outcome with the learning curve being traversed (Chung et al. 2012; Choi et al. 2016; Lau et al. 2017).

Table 17.1 Summary of current literature from Asian countries on Laparoscopic ureteral reimplant in Children since 2008
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3.2 Current Status of Robotic Assisted Laparoscopic Ureteral Reimplants Worldwide and Asian Countries

In the recent years, robot assisted laparoscopic ureteral reimplant is becoming a more prevalent approach for children with VUR (Weiss and Shukla 2015; Bowen et al. 2016). Two reports from Asian country have also demonstrated their early experience and feasibility of robotic assisted laparoscopic ureteral reimplant in children with acceptable outcome (Table 17.1) (Chan et al. 2010; Hayashi et al. 2014). Several literatures from USA are now available to demonstrate the short term to intermediate outcome of this new approach (Casale et al. 2008; Sorensen 2010; Marchini et al. 2011; Smith et al. 2011; Callewaert et al. 2012; Kasturi et al. 2012; Chalmers et al. 2012; Dangle et al. 2013; Gundeti et al. 2013; Schomburg et al. 2014; Akhavan et al. 2014; Dangle et al. 2014; Faasse et al. 2014; Diaz et al. 2014; Silay et al. 2015; Grimsby et al. 2015; Arlen et al. 2016; Herz et al. 2016; Kurtz et al. 2016; Gundeti et al. 2016; Boysen et al. 2017). Although still at its infancy stage, the clinical outcome reported are mostly for extravesical approach and the rate of success varies from 72% to 100% with some factors need to be considered as discussed by some of the authors (Table 17.2).

Table 17.2 Current literature on Robotic Assisted Laparoscopic ureteral reimplants in Children
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4 Considerations in Minimally Invasive Approach for Ureteral Reimplants in Children

4.1 Advantage and Disadvantage of Minimally Invasive Approach in General

Minimally invasive approach using laparoscopic ureteral reimplant for children with VUR has shown to have comparable result with the open counterpart procedure, while sustaining the clinical benefit of less postoperative pain, lower postoperative morbidity of endoscopic procedures (Esposito et al. 2016). Additionally, recent survey reported that urological surgery scars in children seem to influence the decision of parents and patients on the approach of the surgical procedure and favours minimally invasive ureteral reimplant over the open approach (Barbosa et al. 2013). However, some authors contradicts this opinion by describing that small scar may not always be the preference of the family and patient, special consideration must also focused on the scar location for concealment (Gargollo 2011; Garcia-Roig et al. 2017).

Pure laparoscopic approach was said to have limitation on the manipulation of the instrument intracorporally, whereas the robotic assistance improve the dexterity, motion scale, magnification of vision with spatial depth perception and enhance fine movement which could offset the disadvantage of lack of haptic feedback (Schomburg et al. 2014; Phillips and Wang 2012). While still in its infancy stage, laparoscopic with robotic assistance seems to incur higher cost, longer operative time and some related morbidity (Kurtz et al. 2016; Arlen et al. 2016). Recent literature argued that the shorter hospital stay and lesser need for post-operative analgesia may indeed offset the related cost (Smith et al. 2011; Hayashi et al. 2014; Schomburg et al. 2014; Harel et al. 2015).

4.2 Advantage and Disadvantage of Laparoscopic Extravesical and Intravesical Approach with or Without Robotic Assistance

Majority of the recent minimally invasive approach on ureteral reimplants in children were reported to be robotic assisted laparoscopy (Tables 17.1 and 17.2) and specifically applying the extravesical approach. The extravesical approach of Lich-Gregoir was previously described to have the advantage of its technical simplicity, with avoidance of bladder intrusion and or vesicoureteral anastomosis, which then rendered less post-operative pain, shorter recovery period and some bladder related postoperative morbidities such as hematuria and bladder spasm (Schwentner et al. 2006; Hayashi et al. 2014; Silay et al. 2017). Similar advantage of this approach holds true for minimally invasive ureteral reimplant (Casale et al. 2008; Lopez et al. 2011). Although open extravesical bilateral ureteral reimplant was once reported to have increased incidence of post-operative bladder dysfunction, which was thought to be due to injury of pelvic plexus (Fung et al. 1995; David et al. 2004). However, with the improved visualization of minimally invasive approach, this concern was addressed by precise dissection of the ureter and bladder that avoids the pelvic plexus, which is described to be 1.5 cm dorsal and medial to ureterovesical junction (UVJ) (Chan et al. 2010; Dangle et al. 2014; Marchini et al. 2011; Kasturi et al. 2012; Riquelme et al. 2013). This being said, yet the potential disadvantage of extravesical approach includes the risk of bowel injury (Tsai et al. 2008), ureteral injury (Marchini et al. 2011), unsuitable for ureters that need tailoring (Javali et al. 2015), challenge in creating detrusor channel (Javali et al. 2015; Kojima et al. 2012). As such, it is recommended to incorporate technical modifications and preventive measures to avoid these complications.

Minimally invasive intravesical/pneumovesical approach of ureteral reimplant was described to have the advantage of replicating the gold standard open procedures (such as Cohen, Politano-anderson, Anderson-Leadbetter) with complete extraperitoneal access and reducing the chance of visceral perforation as well as performing concomitant intravesical procedures (Valla et al. 2009; Emir et al. 2012; Bayne et al. 2012). Furthermore, it allows ability to create longer submucosal tunnel and addressing bilateral VURs (Soh et al. 2015). However, the disadvantage lies on the limited intravesical space with short distance and acute angle between the trocars leading to difficult navigation and manipulation of the surgical field (Soh et al. 2015; Hong et al. 2011) The presence of risk for port dislodgement and water tight closure of these ports needs to be assured to prevent complications (Valla et al. 2009; Hong et al. 2011). Likewise, it was described that this approach has steep learning curve, although once traversed good surgical outcome can be achieved (Schober and Jayanthi 2015; Valla et al. 2009).

4.3 Considerations on Patient Selection and Factors for Good Surgical Outcomes

Several studies have analyzed clinical factors affecting the surgical outcome. Most of the reported initial experiences in laparoscopic ureteral reimplant with or without robotic assistance have recommended careful selection of patient that would be suitable for the procedure. Younger patient (<3 year old) tend to have poor surgical outcome, due to smaller working space; this issue hold true for both intravesical and extravesical approach with or without robostic assistance (Gundeti et al. 2013; Herz et al. 2016). Furthermore, through the intravesical approach, a small bladder volume, specifically less than 130 cc, with narrow pelvic space limits the positioning of the trocar causing issue on clashing instrument and mobility (Kutikov et al. 2006; Hong et al. 2011; Chung et al. 2012; Finkelstein et al. 2015). It may not be ideal to perform minimally invasive approach among patients with prior abdominal surgery with severe intraperitoneal adhesion, which could impede trocar placement and potentially adds excessive operative time for lysis (Sávio and Nguyen 2013; Phillips and Wang 2012). Although some authors suggest that positional modification and appropriate minimally invasive instruments may overcome these limitations and considered them as relative contraindications (Lendvay 2008; Casale and Kojima 2009; Bayne et al. 2012; Sávio and Nguyen 2013) Megaureter or concomitant ureterocoele that needs tailoring is another consideration for their suitability, which needs the surgeons’ expertise or further modification of the technique to improve the surgical outcome (Ansari et al. 2006; Bi and Sun 2012; Khan et al. 2017). Patients with co-morbidities such as severe bladder bowel dysfunction or other medical conditions have been shown to be associated with poor surgical outcome, which should need adequate preoperative counselling to make informed decision making. (Herz et al. 2016; Lendvay 2008; Kurtz et al. 2016).

4.4 Considerations on Potential Complications and Respective Management

Although reported with low occurrence of complication associated with laparoscopic ureteral reimplant with or without robotic assistance, these complications should be adequately managed or even prevented. Table 17.3 summarizes the approximate occurrence of complications base on the current literature with study series of 20 or more cases and their proposed management (Marchini et al. 2011; Hong et al. 2011; Chung et al. 2012; Weiss and Shukla 2015).

Table 17.3 Perioperative complications of minimally invasive ureteral reimplant for VUR in Children
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5 Advancement of Technology and Techniques in Minimally Invasive Ureteral Reimplant in Children

In addressing some inherent limitation of minimally invasive approach of ureteral reimplant in children, technique modifications and new technique application have been proposed by several recent studies to improve surgical outcome. A good amount of Asian literatures are available in describing new techniques to improve perioperative outcomes (Okamura et al. 1996; Ansari et al. 2006; Tsai et al. 2008; Chan et al. 2010; Kojima et al. 2012; Hong et al. 2011; Chung et al. 2012; Soh et al. 2015; Javali et al. 2015). The following bullet points summarize the available literatures on innovative techniques and application of new technologies to improve surgical outcomes:

  • Application of balloon or rocking trocar ports to prevent inadvertent port dislodgement (Okamura et al. 1996; Dangle et al. 2014)

  • Diamond flex retractor or vessel loop over the ureter thru an extraport to ensure atraumatic handling of ureter (Lakshmanan 2000)

  • Intravesical pressure limited within 6–8 mmHg not over 10 mmHg to prevent intraoperative bladder spasm and optimise intravesical suturing and manipulation (Kutikov et al. 2006)

  • Extracorporeal ureteral tailoring thru an instrument port (Ansari et al. 2006)

  • Lower coagulation setting on dissection at UVJ to avoid ureteral compromise and prevent post-operative ureteral edema, stenosis and urine leak (Canon et al. 2007)

  • Pelvic nerve sparing ureteral dissection for extravesical approach to prevent post-operative bladder dysfunction (Casale et al. 2008; Tsai et al. 2008; Chan et al. 2010; Dangle et al. 2014)

  • Urethral route on instrument placement (Kawauchi et al. 2009)

  • Intracorporeal ureteral tailoring to maintain rotational orientation or dislodge of the ureter (Faasse et al. 2014)

  • Anterior bladder hitch stitch to improve exposure (Chalmers et al. 2012)

  • To lengthen the mucosal tunnel by performing ureteral advancement suture with empty bladder to ensure good visualization of UVJ (Kojima et al. 2012)

  • Bladder wall anchoring suture to prevent port dislodgement; lateral placement of trocar to achieve wide angle for mucosal tunnel procedure, vessel loop tagging on the lower ureteral segment for bidirectional tunnelling thru the neohiatus (Hong et al. 2011; Chung et al. 2012)

  • Carbon dioxide laser detrussoraphy (Faasse et al. 2014; Diaz et al. 2014)

  • Endoscopic/cystoscopic assisted procedure (Soh et al. 2015)

  • Detrusor top down anchoring suture without stent placement (Silay et al. 2015)

  • Intravesical detrusorraphy with Politano-Leadbetter technique to create long submucosal tunnel and being more effective for higher grade VUR and rendering orthotopic location of orifice (Soh et al. 2015)

  • Maintaining bladder volume at one-third full for easy visualization of UVJ while preventing tense bladder predisposing to bladder mucosal perforation (Javali et al. 2015)

  • Recently described surgical points to ensure good surgical outcome, in particular for extravesical approach is called LUAA to represent adequate length of detrusor tunnel of 5 cm (L), use of a U stitch (U), placement of permanent ureteral alignment suture (A), and inclusion of ureteral adventitia (A) in detrusorraphy to prevent ureter slipping off the tunnel while not inducing obstruction (Gundeti et al. 2016)

6 Training in Asia

Aside from careful selection of suitable patient to achieve successful surgical outcome with minimally invasive approach ureteral reimplant in children, the literature has enumerated other key factors. Such as (1) Incurring high volume cases to traversing the steep learning curve. (2) Availability of minimally invasive program (Casale et al. 2008; Sorensen 2010; Hong et al. 2011; Chung et al. 2012; Choi 2016; Schober and Jayanthi 2015; Weiss and Shukla 2015; Gundeti et al. 2016; Boysen et al. 2017). Although there are several publications reported from Asian countries; however these were confined to only few centers (Table 17.1). The reason for this could be due to lack of minimally instruments and robotic facility secondary to limited resources, and availability of minimally invasive experts in the region. To address these constraints, initiation of training centers for minimally invasive procedures in Asia is recommended. Sorensen et al. (2010) has shared their experience and proposed guidelines to initiate robotic minimally invasive surgery program (Sorensen 2010). The general recommendations includes: dedicated surgical team, dedicated operative days, committed administration, robotic/minimally invasive surgeon subspecialization, innovation to expand minimally invasive approach application and recognize technical differences in individual pediatric patients (Sorensen 2010).

7 Controversies and Future Directions

Being critical on appraising the current literature, several factors need to be considered. Most of the available studies are retrospective in nature, with inherent limitation of uncontrolled confounding factors, selection bias as well as reporting bias. Presence of publication bias with favourable results is likely being published may give an overestimation of clinical success or underestimation of complication rate with minimally invasive approach ureteral reimplant in children (Grimsby et al. 2015). Likewise, with the decrease trend of post-operative voiding cystourethrogram (VCUG) in assessing surgical success, where the recent studies comparing efficacy with open procedure might not be able to give an actual picture of VUR resolution (Herz et al. 2016). Future prospective studies with multi-institutional collaboration to assess patient characteristics and technical difference that render long term optimal clinical outcome are therefore recommended.

To date, even with the application of robotic system to address the ergonomic aspect of the approach, or traversing the steep learning and technical modification; the perioperative outcome of minimally invasive ureteral reimplant compared to open procedure still showed longer operative time (Arlen et al. 2016; Kurtz et al. 2016; Gundeti et al. 2016). Hence, promoting the development and application of new technology and or further technical modification to improve procedural efficiency and safety are still imperative.