Technical aspects and outcome review of continent catheterizable channels in the adult neurourologic population.

Multiple techniques for the creation of continent catheterizable channels have been reported. Several continence mechanisms have been used, including tunneled flap valves, nipple valves, and hydraulic valves. Moreover, several organs have been used, including the appendix, bowel, ureters, and bladders. In this review, we describe various techniques and their outcomes in the adult neuro-urological population. Compared to nipple valves, tunneled flap valves using the appendix and other organs are the most commonly performed procedures but have a higher number of reported complications when compared to nipple valves. Hydraulic valves have been largely abandoned due to disappointing long-term results. Copyright:

INTRODUCTION

Continent catheterizable channels provide alternative routes to access native or augmented bladders by clean intermittent catheterization. The major indications for this procedure are the inability to access the native urethra by catheterization either due to a diseased urethra or due to the patient’s physical disability to reach his native urethra because of obesity or spinal cord diseases.[12345] Several techniques have been described in the literature by using different organs, including the bowel, urinary tract, skin, and genital tract.[56] Several continence mechanisms for these catheterizable channels have been used.[57] In this article, we will review the adult literature on continent catheterizable channels, their outcomes, and their long-term complications.

Appendicovesicostomy (Mitrofanoff procedure)

The use of the appendix as a continent catheterizable channel was first described by Mitrofanoff in 1980 for pediatric patients with neurogenic bladder.[8] Shortly, thereafter, this procedure became popular, and it has since been expanded to various indications and adult populations.[9] It is an attractive approach, as the appendix is a readily available tubular organ that can be used without significant sequelae affecting the gastrointestinal tract. The continence mechanism of this procedure is the tunneled flap valve.

The basic technique of this procedure is to isolate the appendix [Figure 1a]. If needed, a cecal cuff can be included with the appendix to gain extra length [Figure 1b].[10] After mobilization of the appendix, the distal end is then transected, spatulated and implanted through a 2–4 cm submucosal tunnel into the native bladder in a fashion similar to ureteral reimplantation [Figure 1c]. The proximal end is then delivered to the skin in a straight line, usually to the umbilicus or to a location accessible to the patient. There should be no tension on the appendix. Then, the stoma is made in the U, V or VQZ flap of the skin using interrupted sutures.[511] A size 14F catheter is usually used to stent the appendix.[1112]

Figure 1

Appendicovesicostomy (Mitrofanoff procedure) (a) Excision of the appendix from the cecum with its intact mesoappendix. Closure of the cecal opening is performed with an absorbable purse-string suture. (b) In the case of a short appendix, the surgeon might take a cecal cuff using a gastrointestinal anastomosis stapler device while preserving the mesoappendix. (c) An appendicular distal tip is implanted through a 2–4 cm submucosal tunnel into the native bladder in a similar fashion to ureteral reimplantation to create a tunneled flap valve

Reconfigured ileal channel (Yang-Monti procedure)

Yang[13] and Monti et al.[14] described this technique. Although it was first described in the pediatric urology literature, it has been reported to be used for adults when the appendix is stenotic, is absent due to a previous appendectomy, has been previously used for Malone antegrade continence enema, or is short.[15] The basic principle of this procedure is to isolate a 2-cm ileal segment, detubularize it on its antimesenteric border, and then retubularize it in the transverse direction [Figure 2a–c], creating a longer but narrower segment that is then implanted in the bladder in a tunneled fashion and to the skin, similar to Mitrofanoff appendicovesicostomy. Single Monti usually results in a 6 cm channel.[16] In the case of a short channel, the use of a second segment (double Monti) [Figure 3a] or spiral or Z-shaped reconfigured ileum (Casale procedure) has been described. The use of a 3.5 cm ileal segment and retubularization in a Z-shaped fashion will result in a channel length of 10–14 cm [Figure 3b].[16] In addition, the use of a short appendix and anastomosis to reconfigure the ileum using combined Yang-Monti and Mitrofanoff techniques has been described in a case report.[17]

Figure 2

Yang-Monti reconfigured ileal channel. (a) Isolation of a 2–3 cm segment of the ileum with its mesentery and opening of this segment on its antimesenteric border. (b) After opening the ilium on its longitudinal access, the surgeon will flip the opened segment on its vertical access to create a narrower and longer channel. (c) Creation of the reconfigured ileal channel using absorbable suture over a 12F catheter. The expected length of this segment is 6 cm

Figure 3

(a) Double Monti reconfigured ileal channel. 1: Isolation of the 6 cm ileal segment with its intact mesentery. 2: Division of this ileal segment into two segments, each 3 cm in length. 3: Opening of both segments on its longitudinal access and then flipping the segments on its transverse access. 4: By using absorbable sutures, the edges of the longitudinally opened ileal segments will be reconfigured and closed on its transverse access over a 12F catheter, and then the 2 segments will be connected to each other using absorbable sutures. 5: The resulting channel will have a 10 cm channel that will be implanted into the bladder and the skin in a similar fashion to the appendicular channel. (b) Spiral reconfigured ileum (Casale procedure). 1: Isolation of 3.5 cm of ileum with its mesenteric blood supply. 2: Transverse cutting of the isolated segment is carried out at its middle segment, with longitudinal cutting of the 2 segments in opposite directions near the pedicle (Z-shaped). 3: The edges of the 2 segments are straightened, and the corners around the mesentery are sewn to the main strip. 4: Tubularization over a 12 F catheter with absorbable sutures is performed, which will result in a 12-14 cm segment

The outcomes, complications, and long-term follow-up of the tunneled flap valve (Yang-Monti and Mitrofanoff)

In contrast to the pediatric urology literature, the adult urology literature has limited case series with small patient numbers that report long-term outcomes of performing tunneled continent catheterizable channels, and most of these studies grouped the patients who underwent Mitrofanoff, Monti, double Monti, Casale and/or tapered ileum procedures into one category and reported the overall outcomes for all of them.[1181920212223] The reported follow-up was up to 190 months. The reported stomal continence rate in adult series ranges between 100% and 66%, and the reported total continence rate is between 96% and 66%. The definition of incontinence was not clear in the studies; some studies reported only incontinence that needed intervention, while others reported all incontinence rates. The overall revision rate for complications varied from 20% to 67%. The risk of stenosis also varies between case series from 6.8% to 54%. The stenosis level was reported to be at the skin or more proximally at the fascia level or bladder level.

Comparisons among Mitrofanoff, Monti, Spiral Monti, and double Monti are limited in the adult literature. In the pediatric urology literature, the risk of complications is higher with the spiral, double Monti and single Monti procedures than with the Mitrofanoff procedure.[5] The revision rate, when compared to the Mitrofanoff procedure, is two times higher for the Monti procedure and four times higher for the spiral Monti procedure.[24] Furthermore, the subfascial revision is higher with the use of spiral Monti with a stoma at the umbilicus level.[2425] Double Monti has been associated with diverticular pouch formation, reported in a case series to have an incidence of up to 28%.[522]

In a recent, large adult series (176 patients) with a median follow-up of 78.6 months, the reported overall continence rate at last follow-up was 90.2%, with a higher rate of continence in the appendicular channel than in the ileal channel (95.2% vs. 84.0%, P = 0.045). Furthermore, the researchers reported a 100% rate of continence in ureter channels and only a 12.5% continence rate in tapered ileum cases. Fifty-five percent of their patients reported difficult catheterization, which was higher in appendicular and reconfigured ileal groups (57.5% and 53.3%, respectively) and lower in tapered ileum and ureter channels (37.5% and 25%, respectively). Forty-one percent of patients required skin level revision, which was not different between the appendicular and ileal groups (43.7% vs. 37.3%, P = 0.41), but complete revision for either channel stenosis or incontinence was higher in the ileal group than in the appendicular group (overall revision 50.7% vs. 29.9%, P = 0.003, channel stenosis 22.7% vs. 17.2%, P = 0.39, and incontinence 36.0% vs. 19.5%, P = 0.03).[23]

Other described procedures using a tunneled flap valve

Other segments have been used as continent catheterizable channels. These include the ureter, bladder, tapered ileum, stomach, fallopian tube, vas deferens, and skin. A tunneled flap valve was used as a continence mechanism for those procedures.

The use of the ureter has been described since Mitrofanoff’s first description of his procedure in 1980.[8] The ureter is preferred over the appendix when available (i.e., dilated ureter in a nonfunctioning kidney). The proximal ureter is anastomosed to the contralateral ureter by transureteroureterostomy, or ipsilateral nephrectomy is performed for nonfunctioning kidneys. Then, the distal segment will be reimplanted in a nonrefluxing fashion with careful dissection to preserve the blood supply, and the proximal segment will be implanted into the skin using the V flap or VZQ technique.[26] This procedure has been described mainly in the pediatric literature, with no reported case series for adults. The need for transureteroureterostomy and the fraught risk of incontinence and stenosis, which is slightly higher than that with the appendicular Mitrofanoff channel, have made this procedure less appealing and seldom used.[262728] In a further report by Woodhouse,[29] he stated that the use of a normal nondilated ureter with transureteroureterostomy has not stood the test of time, as the normal ureter has narrowed progressively, and the wall has thickened, leading to the need to form a new conduit in the majority of their patients with a normal caliber ureter, which was not the case in patients with dilated ureters.

The use of the bladder flap as a tunneled channel has been described by Rink et al.[30] in pediatric patients with good bladder capacity. A full-thickness bladder flap was isolated for the extravesical portion of the channel [Figure 4a and b]. Then, the incision was extended to the intravesical part through the mucosa only [Figure 4c]. Next, closure of the mucosa over a catheter [Figure 4d] followed by closure of the lateral mucosal flap was performed to create the continence mechanism [Figure 4e and f].[3031] The reported complication was stenosis, which was reported by Rink et al.[30] to have an incidence of 45%. This incidence was higher in patients with neurogenic bladder (60%) and with umbilical sites (86% vs. 36% for lower abdominal sites).[31] This procedure has been performed on pediatric patients but has not been reported in adults. The major drawback of this approach is that the use of a bladder flap requires a large bladder capacity, which is not the case in the majority of patients needing this procedure.

Figure 4

Bladder tunneled flap channel. (a) Isolation of a bladder flap 2 cm wide and 7 cm or more in longitudinal length. (b) Mobilization of the isolated segment. (c) Mobilization of the bladder mucosa around the bladder segment that will form the subsequent tunnel. (d) Tubularization of the proximal segment of the neotunnel. (e) Continued tubularization of the rest of the extravesical tube via full-thickness closure with absorbable sutures. (f) Closure of the flap mucosa from the submucosal tunnel in the intravesical part of the channel

Another reported approach is the use of the fallopian tube as a catheterizable channel. Although few cases have been reported among a few case series, the use of fallopian tubes has not been popular due to the risk to future fertility. Such use has only been reported in the pediatric literature. The fallopian tube blood supply passes through the ovarian artery, and the distal end is spatulated and attached to the skin, while the proximal end is tunneled into the bladder.[931]

Dykes et al.[32] reported, among their series of pediatric patients who underwent the Mitrofanoff procedure, one case where a preoperative cystogram showed vasal reflux and the vas was found severely dilated intraoperatively, along with a nonusable appendix. They reported the use of the vas deferens as the reimplantation of the proximal right vas into the bladder, and the distal vas was transected at the internal inguinal ring and attached to the abdominal wall skin as a stoma.[32]

The use of a tubularized stomach stoma has also been reported by Bihrle et al.[33] A 12–15 cm segment in the greater curvature is selected and grasped with Babcock clamps, and the distal end is maintained at least 3–4 cm proximal to the pylorus. Next, the short gastric vessels proximal to the segment are divided. The segment will be based on the right gastroepiploic vessels. The left gastroepiploic vessels are divided at the proximal end of the segment, followed by division of the omentum at the same level. Then, a small gastrotomy is made on both ends of the segment, a 12 F catheter is passed, and a bowel clamp is applied just superior to the catheter. Next, the segment is divided just beneath the clamp to isolate it from the stomach [Figure 5a]. Then, the stomach is closed with 3-0 silk sutures [Figure 5b] in 2 layers or divided by a GIA stapler [Figure 5c and d], and the stomach is closed with 3-0 silk sutures. The resulting gastric segment is retubularized over a 12 F catheter with 3-0 polygalactic sutures in two layers or 1 layer if a stapler is used. The distal end is implanted into the reservoir in a 4 cm submucosal tunnel. The proximal end is attached to the abdominal skin in any desired area, as the gastric tube and its vascular pedicle are highly mobile and can be attached to any area in the anterior abdominal wall. It can be done by simple attachment of the gastric mucosa into the skin in four quadrants[33] or by using a V-Y shaped skin flap [Figure 6].[34] Long-term follow-up (median 3.5 years) has been reported for a group of 10 adults and pediatric patients with a 30% risk of peristomal skin irritation and a 20% risk of exuberant growth of granulation tissue at the stoma requiring excision of the stoma at the skin level and reanastomosis to the skin. One patient in their series developed stomal protrusion and severe peristomal irritation with severe ulceration that led to erosion of skin vessels and significant hemorrhage, which was managed conservatively.[34] These complications were attributed to gastric acid secretion. They also reported a 100% continence rate when using tunneled flaps using the Mitrofanoff principle.

Figure 5

Tubularized gastric channel. (a) An 11 cm segment based on the right gastroepiploic vessels in the greater curvature is selected, and the distal end is maintained at least 3–4 cm proximal to the pylorus. (b) The left gastroepiploic vessels are divided at the proximal end of the segment, followed by division of the omentum at the same level. Then, a small gastrotomy is made on both ends of the segment, a 12 F catheter is passed, and a bowel clamp is applied just superior to the catheter. The segment is divided just beneath the clamp to isolate it from the stomach, and the stomach is closed with 3-0 silk sutures in two layers. (c and d) Alternatively, the same stomach segment can be taken by using a gastrointestinal anastomosis stapler

Figure 6

Channel to skin V-Y flap. (a) A V-shaped umbilical incision is made to create a flap, and the channel is spatulated at its upper end. (b) Absorbable sutures are used to approximate the edges of the spatulated channel to the lateral edges of the skin. (c) Completed skin-to-stoma anastomosis in an interrupted fashion

The use of tapered ileum has also been described in the literature. The technique has also been used for both adults and pediatric patients. It involves isolation of 10–12 cm of the distal ileum, then tapering it over a 12 F catheter along its antimesenteric border using a GIA stapler device [Figure 7a]. The reservoir end is tapered and closed with absorbable sutures [Figure 7b] and then tunneled submucosally [Figure 7c] after careful dissection of the mesenteric fat at this end. Alternatively, the tapered ileum can be stapled to the bladder with a TA stapler using hydraulic pressure as a mechanism for continence [Figure 8]. Then, the stomal end is brought to the abdominal wall skin and anastomosed in a V-Y fashion.[35] The short-term (mean 14.5 months) follow-up of this small series of 8 patients showed a 30% risk of catheterization difficulty, and one patient had stomal stenosis that needed reoperation. One patient had incontinence requiring reoperation.[35] The adaptation of the tapered ileum has been limited due to the use of a long ileal segment that might accompany augmentation, which will cause more loss of the bowel segment, along with the introduction of the Yang-Monti procedure, which uses less ileal length.

Figure 7

Tapered ilium channel. (a) Isolation of a desired ileal length (10–12 cm) with its intact mesentery. This segment will be tapered over a 12-French catheter with the use of a gastrointestinal anastomosis stapler at its antimesenteric side. (b) The reservoir edge of the stapled segment is tapered and sutured with absorbable sutures. (c) The reservoir end of the tapered ileum is implanted into the native bladder with a 2 cm submucosal tunnel

Figure 8

Continent Stapled direct ileovesicostomy. (a) An opening on the bladder wall is made, wide enough to pass the ileal segment. (b) The tapered ileal segment passed the bladder. (c) A second opening is made into the bladder at least 5 cm inferior to the first opening, and it should be wide enough to pass the thoracoabdominal linear stapler device. (d) The TA linear stapler device is passed through the lower bladder incision, and the ileal segment is also passed between the bladder wall and the jaw of the stapler device. Then, after stapling the ileal segment into the bladder wall, the lower bladder incision is closed, and the defect around the ileal segment entry (upper incision) is closed with absorbable sutures. The continence mechanism for this technique will be based on the hydraulic pressure applied on the stable ileal segment with increased abdominal pressure

The use of tubularized skin flaps has also been reported. The use of preputial skin has been reported in 3 cases by Krstić,[36] with 7 months of follow-up without complications in pediatric patients. Perovic S reported the use of preputial and clitoral skin flaps that were used as catheterizable channels in 14 male patients and seven female patients (both children and adults) with a mean of 6 months of follow-up and minimal complications.[37] One patient had a kinked tube that was corrected endoscopically, and 1 had incontinence that was managed with collagen. This procedure has not been adopted widely, as it is technically demanding, and no reported long-term follow-up for this procedure has been reported.

Abdominal wall skin has also been used as a channel in adults and children.[3839] This has been reported in adults to have unacceptably high failure rates. The reported stenosis occurred in all patients within a mean time of 24 days.[3940]

Another reported organ used for the creation of a tunneled flap valve is Meckel’s diverticulum, which was reported in two case reports of pediatric patients: A child 6 years old and a teenaged girl.[4142] A follow-up of up to 14 months revealed no complications.[42]

Nipple valve continence mechanism

This technique involves the use of intussusception of the ileum to create a nipple valve, similar to the ileocecal valve, to provide continence by circumferential coaptation. This was first described by Kock as an efferent limb in the Kock pouch.[43] Later, it was modified to be used as an isolated outlet channel.[44] The creation of an intussuscepted ileal nipple flap valve involves isolation of a 12–15 cm ileal segment 15 cm away from the ileocecal valve. Then, after the continuity of the bowel is restored, the mesentery is divided from the ileum over 5 cm in the middle of the resected segment at ≈ 1 cm from the ileum. The mucosa of the middle segment is grasped from the distal end, anastomosed to the bladder, and intussuscepted [Figure 9a]. Next, with the use of a TA stapler, the intussuscepted ileum is stapled at the antimesenteric side (6 o’clock) [Figure 9b], followed by the second line of stapling at 2 o’clock. An opening at the reservoir (bladder) is made [Figure 9c], followed by stapling the outer leaflet of the intussusception into the external bladder wall at the 10 o’clock position [Figure 9d]. Then, anastomosis of the intussuscepted segment into the reservoir with absorbable sutures is performed, followed by external fixation of the intussuscepted ileum to the reservoir wall with interrupted absorbable sutures. The stomal part is anastomosed to the umbilicus, with skin and ileal spatulation and 16 F and 10 F catheters for irrigation and drainage [Figure 9e]. The procedure is nicely illustrated by Thüroff et al.[44] Deuker et al.[45] reported the long-term follow-up of 47 pediatric and adolescents who underwent this procedure. The stenosis risk of this stoma was reported to be 20%, and 82% of the patients were continent over a median follow-up of 15.9 years. The rate of revision due to incontinence was 20%.[45] When compared to the corresponding rates obtained with the submucosally embedded appendix in their series, the stenosis rate was 49%, and the incontinence rate was 1.8%.[44] Skinner et al.[46] reported their series of Kock pouches using ileal intussuscepted nipple valves for over 500 patients and found a continence rate of 86% and a stenosis rate of 2.6%.[46] Wiesner et al.[47] reported their large case series of over 200 adult patients who had ileal intussuscepted nipple valves. The rate of revision was 17%, and the risk of stenosis at 10 years was 18%. Thirty-four percent had stone formation that required endoscopic intervention. The stone-free rate at 10 years was 74.3%. Comparison with their patients receiving the submucosally embedded appendix revealed that the risk of stomal stenosis was higher with the appendix (32% compared to 18%), and the risk of stone formation was higher in the intussuscepted nipple valve than in the appendix (34% compared to 25%).[47]

Figure 9

The intussuscepted ileal nipple flap valve. (a) After isolation of the 12-15 cm ileal segment, the mesentery is divided from the ileum over 5 cm in the middle of the resected segment at ≈ 1 cm from the ileum. Then, the mucosa of the middle segment is grasped from the distal end and intussuscepted. (b) Next, with the use of a thoracoabdominal (TA) stapler, the intussuscepted ileum is stapled at the antimesenteric side (6 o’clock). The staplers on the inner end are removed to avoid staplers inside the bladder. (c) An opening at the bladder is made, and the channel is passed through the bladder. (d) Stapling the outer leaflet of the intussusception into the external bladder wall at the 10 o’clock position. (e) The stomal part of the channel is passed through the fascia and the skin. The channel is fixed to the fascia with absorbable sutures to prevent parastomal hernia. The channel is anastomosed to the skin (umbilicus or other area), with skin and ileal spatulation; 16F and 10F catheters are used for irrigation and drainage

Application of the nipple valve is also employed in the use of the reinforced ileocecal valve. Kock initially described the use of ileocecal valves for continent cutaneous diversion in the ileocecal reservoir.[41] Then, it was described as part of the Indiana pouch for the continent reservoir after cystectomy for bladder cancer.[48] Later, it was described as part of bladder augmentation and called a hemi-Indiana pouch or continent catheterizable ileal cecocystoplasty.[549] The procedure is performed by harvesting 10 cm of the cecum and 10 cm of the terminal ileum [Figure 10a]. Then, after detubularization of the cecum at its antimesenteric border, the ileum will be tapered with a GIA stapler over a 14F catheter [Figure 10b and c]. Alternatively, the terminal ileum can be plicated with nonabsorbable sutures [Figure 10d]. The ileocecal valve is reinforced with interrupted imbricating slowly absorbable sutures or nonabsorbable sutures [Figure 10e].[5484950] The detubularized cecum is then anastomosed to the bivalved bladder using absorbable sutures [Figure 10f]. The stomal end is anastomosed to the skin in a similar fashion to a Mitrofanoff stoma. This procedure is reported to be performed along with an augmentation, not as an outlet procedure only. The continence rate with this procedure is reported in multiple case series in the range of 95%–87%. Stomal stenosis is reported in 6%–15% and stone formation in 5.9%–15%.[550515253]

Figure 10

Reinforced ileocecal nipple valve (a) Isolation of 10 cm of the cecum and 10 cm of the terminal ileum. (b) Detubularization of the cecum on its antimesenteric borders and tapering of the terminal ileum is performed over a 12 or 14 French catheter using a gastrointestinal anastomosis stapler device. (c) The gastrointestinal anastomosis stapler plication of the ileum is ended at an angle 2–3 cm away from the cecum to avoid stapling the ileocecal valve. (d) Alternatively, the ileum can be plicated over a 12–14 French catheter with interrupted plicating Lembert sutures in opposite directions, spaced every 3–4 cm, using nonabsorbable sutures. (e) The ileocecal valve is plicated with Lembert sutures in an interrupted fashion using 6 or 7 nonabsorbable or slowly absorbable sutures. A 14 French catheter should be moved after each stitch to confirm the patency of the lumen with some resistance. If the catheter cannot pass, the suture should be removed, and the suture should be performed again without obstructing the lumen. (f) The cecum is bilaterally anastomosed to the widely bivalved bladder at the bladder neck with absorbable sutures

Hydraulic valve continence mechanism

Another continent mechanism that has been described in the literature is the hydraulic valve. Benchekroun reported the use of his technique to create hydraulic valves.[54] A 14 cm ileum is first harvested with its intact mesentery. Then, it is folded inward on itself for the entire length. Next, it will be attached to the reservoir, leaving a distinct space between the inner and outer ileal walls that will be filled with urine and provide compression with filling. The initial follow-up[54] showed a continence rate of 75% and a valve failure rate of 17.6% with a mean follow-up of 38 months. Sanda et al.[55] conducted a 5-year follow-up of this procedure, which showed disappointing results, with 91% requiring revision. The rate of stomal stenosis was 73%, that of stone formation was 36%, and that of devagination was 36%. This procedure has been abandoned because it is surgically demanding with poor long-term results.[7]

Comparison of outcomes between continent catheterizable channel techniques

When comparing tunneled channels to continent cutaneous cecocystoplasty with ileocecal valves, Redshaw et al.[1] found a higher rate of secondary procedures with tunneled channels than with continent cutaneous cecocystoplasty (50% vs. 13%). Stomal leakage was similar between the two groups (29% for cecocystoplasty vs. 43% for tunneled channels, P = 0.12).[1]

DISCUSSION

Which technique to use? It is clear that the best technique is the one that can be mastered while limiting the risks of reconstruction mistakes, preventing complications and facilitating their management when they occur. The choice of the best technique can also be dictated by published outcomes summarized in a systematic review of the use of continent catheterizable channels in adult neurourological patients recently conducted by Phé et al.[56] They found that the overall catheterization ability for all patients was above 84% in all types of stomas, with a continence rate of more than 75% and a follow-up range from 1.8 to 8.7 years (median follow-up 36 months). Channel stenosis ranged between 4% and 33%, and the overall rate was 15%. The lowest rate of stenosis was reported to occur with the Indiana pouch (reinforced ileocecal valve) and ranged between 4.2% and 11.8%. In addition, the researchers reported that the highest stenosis rate was found in the Mitrofanoff/Casale principle (tunneled valve), with a channel stenosis rate of 32.3%.[56]

CONCLUSION

Various techniques have been described to create a continent catheterizable channel. Currently, the use of the appendix and other flap valve techniques are the most commonly performed procedures but have higher reported complications, such as stenosis and incontinence, than nipple valves. The surgeon should be familiar with these various techniques and their limitations. Future studies must focus on comparing different techniques in a multicenter prospective fashion, as most of the current literature is derived from small retrospective case series. In addition, we should modify the current techniques to lower the rate of complications and optimize outcomes.

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Conflicts of interest

There are no conflicts of interest.