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Seromuscular Colocystoplasty Lined With Urothelium (SCLU)

Seromuscular colocystoplasty lined with urothelium (SCLU) is a form of augmentation cystoplasty that uses a demucosalized colonic segment placed over an autoaugmented bladder, allowing the native urothelium to line the augmented reservoir while the colonic seromuscular layer provides structural support. Developed by González and colleagues in the early 1990s, SCLU was designed to achieve the capacity and compliance benefits of enterocystoplasty while aiming to reduce bowel-mucosa-related metabolic exchange and mucus. SCLU may still carry risks of stones, perforation, bowel complications, and malignancy.[1][2]

Concept and Rationale​

Standard enterocystoplasty's central problem is intestinal mucosa in contact with urine: metabolic derangements, mucus, stones, long-term malignancy risk. Earlier attempts to simply strip mucosa from bowel and use the seromuscular layer caused fibrosis and contraction. SCLU combines two principles to solve this:[1]

  1. Detrusorectomy (autoaugmentation): detrusor excised from the dome, exposing the underlying urothelium, which prolapses outward.
  2. Seromuscular colonic patch. Demucosalized sigmoid colon placed over the prolapsed urothelium, providing a supporting layer intended to reduce urothelial retraction and fibrosis.

The result is a composite augmentation: luminal surface is urothelium (from native bladder); outer wall is colonic seromuscular tissue.[1][2]

Experimental Foundation​

The canine model (Buson, González 1994) established findings:[1]

  • When the intestinal submucosa was preserved on the seromuscular patch, there was no fibrosis and capacity was preserved.
  • When the submucosa was not preserved, there was moderate contraction with subepithelial fibrosis and capacity loss.
  • In animals with previously reduced bladder capacity, SCLU effectively augmented.
  • Seromuscular patches remained viable and well-vascularized.
  • Native bladder urothelium and lamina propria were preserved beneath the patch. This differs from earlier rat experiments that used the serosal surface as a luminal lining.

In the de Badiola 1991 rat model, urothelial growth on the seromuscular colonic patch was first noted at 5 days; histology in 40 rats showed no fibrosis or inflammation, and none of 22 patches measured at sacrifice had shrunk. The 40 rats were examined 5–80 days after surgery.[3]

These animal studies supported preserving submucosa in the original SCLU technique. Other demucosalized constructs use different dissection planes to reduce mucosal regrowth; operative steps vary by construct.[1]

Surgical Technique​

Step 1 — Detrusorectomy​

A generous detrusorectomy over the bladder dome, excising the detrusor muscle while preserving the underlying urothelium and lamina propria. The urothelium prolapses through the muscular defect, creating a large epithelial bulge.

Step 2 — Sigmoid colon harvest and demucosalization​

  • 15–20 cm of sigmoid colon isolated on its vascular pedicle.
  • Bowel continuity restored by primary anastomosis.
  • Colonic segment detubularized along its antimesenteric border.
  • The original SCLU method preserves intestinal submucosa and muscularis mucosae while removing the epithelial lining. Demucosalization depth is technique-specific: deeper removal has been studied to reduce residual crypt regrowth, but may affect patch integrity. Confirm the selected technique rather than merging conflicting dissection planes.

Step 3 — Composite anastomosis​

  • The vascularized patch supports the exposed native urothelium. The original operative description should determine patch orientation; the serosa-as-lumen rat experiment is not an instruction to invert a clinical SCLU patch.
  • Edges of the seromuscular patch sutured to the edges of the detrusor defect.
  • Preserve and appose the native urothelial layer; mucosal injury or separation can compromise the construct. González and Ludwikowski describe maintaining bladder distension at about 20 cm H₂O during the first postoperative week to promote coaptation, provided the bladder mucosa is watertight.[13]

Step 4 — Concomitant procedures​

  • AUS is frequently implanted simultaneously or has been placed previously as one selected outlet strategy.
  • Bladder-neck procedures or slings as needed. González and Ludwikowski cautioned that simultaneous appendicovesicostomy or ureteroneocystostomy can breach the native urothelium needed for watertight first-week patch coaptation.[13]

Avoiding hourglass deformity[5]​

  • Early in the experience, hourglass deformity developed in 22% of patients.[4]
  • Addressed by ensuring the seromuscular patch is sutured well below the level of the detrusorectomy edge, creating a wider anastomosis.
  • The González AUS series described modifications intended to avoid this complication.[5]

Indications​

SCLU shares the general indications for augmentation but is specifically considered when the surgeon wishes to avoid incorporating intestinal mucosa into the urinary tract:[2][6][7]

  • Neurogenic bladder (myelomeningocele, SCI) with low compliance and/or overactivity refractory to conservative management.
  • Bladder exstrophy and cloacal exstrophy.
  • Posterior urethral valves.
  • Renal insufficiency, where metabolic acidosis from standard enterocystoplasty would be poorly tolerated.
  • Patients with combined reservoir and outlet dysfunction; small series describe SCLU with an AUS, without establishing superiority over alternative reconstructions.[5][7]

Critical Prerequisites for Success​

1. Adequate bladder outlet resistance​

Selected series associate adequate outlet resistance with maintained patch apposition. Abdominal leak point pressure (ALPP) is not storage detrusor pressure, and these findings do not justify maintaining an unsafe high-pressure reservoir. Jung 2012 retrospectively evaluated 33 patients over a mean of 6.0 years:[6]

  • Among 17 patients with simultaneous anti-incontinence surgery, none in the ALPP 40–60 cm H₂O group required further surgery.
  • Four of ten with ALPP below 40 cm H₂O required additional surgery. Two of 16 patients without anti-incontinence surgery eventually required continence surgery, and the authors recommended an ALPP of 60 cm H₂O or less as an indication for simultaneous anti-incontinence surgery.[6]

In González’s retrospective pediatric series, 15 patients underwent SCLU without a concomitant bladder procedure (most had an AUS); none required repeat augmentation, and bladder capacity measured at 30 cm H₂O increased from 60% to 100% of expected capacity for age.[7] By contrast, 3/5 patients who underwent creation of a continent catheterizable channel at the time of SCLU required repeat augmentation.[7]

In González and Ludwikowski's five-patient simultaneous-channel subgroup, the three patients who required repeat augmentation also had prolonged postoperative urinary leaks.[7][13]

2. Intact bladder mucosa​

SCLU should be primarily considered in patients without prior bladder mucosal injury; previous surgery that has damaged the urothelium may compromise its ability to prolapse and line the seromuscular patch.[6]

Synergistic Role of the AUS​

González 2002 in 27 children specifically combined SCLU with AUS:[5]

  • In this retrospective series, 24/27 (89%) achieved study-defined continence (dry between catheterizations or voiding without pads) at a mean follow-up of 1.7 years; six hourglass corrections and two AUS removals were also reported.[5]
  • Bladder capacity, safe capacity for age, and end-filling pressure all improved significantly.
  • No significant upper-tract changes were reported, but two AUS erosions required device removal.[5]
  • Outlet resistance may support patch apposition.
  • The authors favored SCLU for selected patients with adverse storage changes after AUS; this is a center-specific conclusion.

González concluded that SCLU is most effective in patients who already have an AUS or who undergo simultaneous AUS implantation. The 2009 authors advised against a simultaneous catheterizable channel after three failures among five patients.[7]

Outcomes​

The reported SCLU series are predominantly pediatric (mean age at surgery 7.5–11.1 years in several cohorts).[4][6][7][11]

SeriesnFollow-upCapacity ↑ContinenceFailure
González 1995[2]16Mean 12 mo2.4× (139 → 335 mL; paired n = 14)13/16 dry day and night2/16 reaugmented
Jednak 2000[4]32Mean 1.6 yr1.8× total / 2.4× safe (urodynamic n = 28, mean 1.5 yr)71% after initial procedure; 81% after secondary procedures4/32 (12.5%) augmentation failure
González (with AUS) 2002[5]27Mean 1.7 yrSignificant24/27 (89%) continent (dry between catheterizations or voiding without pads)1/27 (3.7%) augmentation failure
González 2009[7]20Mean 53 moCapacity at 30 cm H₂O: 60 → 100% expected for age (Group 1, n = 15, no simultaneous bladder procedure)All 20 patients continent0/15 Group 1; 3/5 Group 2 (with channel) required repeat augmentation
Jung 2012[6]33Mean 6.0 yr2.96×13/33 stopped anticholinergics at 47.3 moAdditional outlet surgery occurred; see subgroup results above
Shekarriz 2000[8]20 SCLU within 133 mixed augmentationsMean 64 mo across whole cohort—95% refers to the whole mixed cohortNo SCLU perforation or SBO observed

Evidence Compared with Standard Enterocystoplasty​

FeatureSCLUStandard Enterocystoplasty
Metabolic disturbancesReduced bowel-mucosa exposure; none reported in selected small seriesMetabolic exchange requires monitoring
Mucus productionNot clinically significant at short-term follow-up in Jednak's seriesCommon; irrigations are often required
Bladder perforationNone observed in cited small cohortsRecognized long-term risk varying by population
Bowel obstructionNone observed in selected cohorts; bowel surgery still carries riskRecognized bowel and adhesion morbidity
Bladder stones1/20 in Shekarriz[8]; 2/32 in Jednak[4]More frequent with continent stomas and in bladder or cloacal exstrophy (32% in exstrophy in Shekarriz's mixed cohort)[8]
Malignancy riskNot eliminated; baseline disease and possible intestinal regrowth remain relevantLong-latency risk; estimates depend on population and follow-up
Capacity increase1.8–2.96×No significant difference in achieved capacity in one retrospective comparison
Surgical complexityHigher (demucosalization + detrusorectomy)Standard

Shekarriz’s retrospective 133-patient comparison included only 20 SCLU patients; none had perforation or SBO during that follow-up. Its authors favored SCLU/sigmoid.[8] Bandi et al.’s retrospective comparison (26 SCLU; 32 conventional augmentations) found no statistically significant difference in achieved capacity, subjective continence, or several subsequent surgery outcomes; both groups remained at risk of stones, reflux, and augmentation failure.[10] In a later pediatric retrospective cohort using ileal or colonic seromuscular patches (n = 37) versus standard cystoplasty (n = 46), mean postoperative capacity was 240 versus 387 mL, compliance was 8.8 versus 26.7 mL/cm H₂O, and end-filling pressure was 44.2 versus 20.7 cm H₂O. Mean group follow-up was 61 versus 36 months; treatment eras and concomitant procedures differed.[11]

Complications​

  • Hourglass deformity. The most characteristic complication; approximately 22% (7/32 in Jednak[4]; 6/27 in the González AUS series, all six requiring correction[5]). Technical modifications (suturing the patch well below the detrusorectomy edge) were described to reduce hourglass deformity after cases in these early series.[4][5]
  • Hydronephrosis and reflux. In Jednak's series new or increased hydronephrosis was present in 6/62 renal units (10%) and reflux in 9/60 (15%) evaluated.[4]
  • Colonic mucosal regrowth. A significant concern. Jednak biopsies showed regrowth in 5/7 (71%)[4]; González’s initial series showed urothelium alone in 7/10 biopsies, colonic regrowth in two, and mixed urothelium/colonic mucosa in one[2]. Dewan found regrowth in 4/5 sheep with preserved muscularis mucosae/submucosa, compared with none after deeper removal; ten clinical patients had no detected regrowth.[9]
  • Augmentation failure and reaugmentation. Retrospective series report reaugmentation in 2/16 over a mean 12-month cohort follow-up[2] and augmentation failure in 4/32 over a mean 1.6-year cohort follow-up[4]. In a later pediatric cohort using ileal or colonic seromuscular patches, 8/37 patients required reaugmentation over a mean 61-month group follow-up versus 0/46 standard-cystoplasty patients over a mean 36-month group follow-up.[11] The paper does not report a colocystoplasty-only rate; treatment era and concomitant procedures differed between groups.[11] Three of five patients with a simultaneous catheterizable channel required reaugmentation in another small series.[2][4][7][11]

Patient Selection Summary​

For children with spinal dysraphism, the 2026 published summary of the 2025 joint EAU/ESPU/ERN guideline describes seromuscular cystoplasty as a selected-case alternative with variable outcomes.[14] The full guideline states that it has not proved as successful as standard intestinal augmentation.[16]

  • Consider selected patients with adequate or surgically achievable outlet resistance, safe storage pressures, and a dependable catheterization route; AUS is one option.[5][6][7]
  • SCLU can be considered primarily when native bladder mucosa is intact and can prolapse beneath the patch; prior surgery that injured this mucosa may compromise the construct.[6]
  • Discuss the limited SCLU-specific evidence suggesting increased failure with simultaneous channel construction.[7]
  • In renal insufficiency, SCLU may be considered to limit direct bowel-mucosal urine exposure.[2][4]
  • After augmentation for neurogenic dysfunction, arrange lifelong, risk-based follow-up in adults and children, including renal and upper-tract surveillance. The 2026 EAU neuro-urology guideline gives Strong recommendations for regular upper-tract assessment and urodynamic investigation at regular intervals in high-risk patients; CUA/PUC guidance addresses pediatric surveillance.[15][12]

References​

1. Buson H, Manivel JC, Dayanç M, Long R, Gonzalez R. "Seromuscular Colocystoplasty Lined With Urothelium: Experimental Study." Urology. 1994;44(5):743-8. doi:10.1016/s0090-4295(94)80220-3

2. Gonzalez R, Buson H, Reid C, Reinberg Y. "Seromuscular Colocystoplasty Lined With Urothelium: Experience With 16 Patients." Urology. 1995;45(1):124-9. doi:10.1016/s0090-4295(95)97364-8

3. de Badiola F, Manivel JC, Gonzalez R. "Seromuscular Enterocystoplasty in Rats." The Journal of Urology. 1991;146(2 Pt 2):559-62. doi:10.1016/s0022-5347(17)37854-0

4. Jednak R, Schimke CM, Barroso U Jr, Barthold JS, González R. "Further Experience With Seromuscular Colocystoplasty Lined With Urothelium." The Journal of Urology. 2000;164(6):2045-9. doi:10.1016/s0022-5347(05)66962-5. PMID 11061922

5. González R, Jednak R, Franc-Guimond J, Schimke CM. "Treating Neuropathic Incontinence in Children With Seromuscular Colocystoplasty and an Artificial Urinary Sphincter." BJU International. 2002;90(9):909-11. doi:10.1046/j.1464-410x.2002.03036.x

6. Jung HJ, Lee H, Im YJ, et al. "Prerequisite for Successful Surgical Outcome in Urothelium Lined Seromuscular Colocystoplasty." The Journal of Urology. 2012;187(4):1416-21. doi:10.1016/j.juro.2011.12.009

7. González R, Ludwikowski B, Horst M. "Determinants of Success and Failure of Seromuscular Colocystoplasty Lined With Urothelium." The Journal of Urology. 2009;182(4 Suppl):1781-4. doi:10.1016/j.juro.2009.02.062

8. Shekarriz B, Upadhyay J, Demirbilek S, Barthold JS, González R. "Surgical Complications of Bladder Augmentation: Comparison Between Various Enterocystoplasties in 133 Patients." Urology. 2000;55(1):123-8. doi:10.1016/s0090-4295(99)00443-4

9. Dewan PA, Close CE, Byard RW, Ashwood PJ, Mitchell ME. "Enteric Mucosal Regrowth After Bladder Augmentation Using Demucosalized Gut Segments." The Journal of Urology. 1997;158(3 Pt 2):1141-6. doi:10.1016/s0022-5347(01)64406-9

10. Bandi G, Al-Omar O, McLorie GA. Comparison of traditional enterocystoplasty and seromuscular colocystoplasty lined with urothelium. J Pediatr Urol. 2007;3(6):484–489. doi:10.1016/j.jpurol.2007.04.004.

11. Sun XG, Wang RY, Xu JL, et al. "Surgical outcomes of bladder augmentation: A comparison of three different augmentation procedures." World J Clin Cases. 2020;8(15):3240-3248. doi:10.12998/wjcc.v8.i15.3240

12. Chua ME, Yadav P, Wang PZT, et al. "2023 Canadian Urological Association/Pediatric Urologists of Canada guideline: Pediatric patients with neurogenic lower urinary tract dysfunction: Full-text version." Can Urol Assoc J. 2023;17(10):E338-E357. doi:10.5489/cuaj.8390

13. González R, Ludwikowski BM. "Alternatives to Conventional Enterocystoplasty in Children: A Critical Review of Urodynamic Outcomes." Front Pediatr. 2013;1:25. doi:10.3389/fped.2013.00025

14. Radmayr C, Abrahamsson K, Bogaert G, et al. "EAU–ESPU–ERN eUROGEN–ERN ITHACA–ERN ERKNet–IFSBH Guidelines on Spinal Dysraphism in Children and Adolescents: Summary of the Guideline." Eur Urol Open Sci. 2026;88:39-53. doi:10.1016/j.euros.2026.04.002

15. Sartori AM, Kessler TM, Ecclestone H, et al. "European Association of Urology Guidelines on Neuro-urology: Summary of the 2026 Update." Eur Urol. 2026;90(3):241-253. doi:10.1016/j.eururo.2026.04.012

16. Abrahamson K, Bogaert G, Dellenmark-Blom M, et al. EAU–ESPU–ERN eUROGEN–ERN ITHACA–ERN ERKNet–IFSBH Guidelines on Spinal Dysraphism in Children and Adolescents. Clinical guideline. EAU Guidelines Office; January 2025. Full guideline