Antenatally Detected Choledochal Malformation: What Are We Waiting For?

INTRODUCTION: An increasing proportion of congenital choledochal malformation (CCM) are being detected on antenatal ultrasound. However, the actual timing of its surgical correction remains controversial with some series showing an excess of complications the earlier the operation. The aim of this study was to characterize the pathophysiological aspects of this cohort from the perspective of age at surgery in order to inform a more rational basis for clinical decision-making. METHODS: We analysed a prospective database of CCM acquired over a 26-year period (Jan. 1997 to Dec. 2022) for patient demography; details of pre- and post-natal imaging; age at surgical intervention; operative complications (Clavien-Dindo classification) and outcome. Data are quoted as median (IQR). All comparisons are non-parametric. A P value of 0.05 was accepted as significant. RESULTS: There were 58 (72% female) children with an antenatally-detected CCM from a total of 265 (21.8%) in the series. These were classified as Type 1C (n = 47; 81%), type 4C (n = 3; 5%) and Type 5 (n = 8; 14%). There were no Type 1F lesions in this cohort. Median age at surgery was 113 (IQR 57-198) days. Postnatal cyst (US) size varied from 12 to 130 mm but there was little evidence of a relationship between this and post-natal liver biochemistry (e.g. bilirubin rS = 0.01, P = 0.44; AST rS = 0.14, P = 0.19). Choledochal pressure measurements (n = 46) showed resting pressures of 12 (9-21) mmHg with no significant correlation with age (P = 0.4) or aspartate aminotransferase (P = 0.2) or γ-glutamyl transferase (P = 0.06). The cohort was divided into 2 groups (Early and Late) based on the median age at surgery (all open) (113 days). Biliary obstruction was more common in the Early group (10 vs. 2; P = 0.01). Two perforations occurred, both in the Early group. With a deliberate policy of regular ultrasound-based follow-up we have seen no anastomotic complications (leak, stenosis, persistent intrahepatic biliary dilatation or stones) or post-operative cholangitis in any child [median follow-up 3.42 (1.30-8.05) years]. CONCLUSIONS: This is one of the largest series documenting the outcomes of antenatally-detected CCMs, certainly in Europe and North America. Such lesions are invariably cystic in nature, and either Types 1C, 4C or 5. The absence of complications using a policy of early intervention (where possible) in experienced hepatobiliary units was shown. EVIDENCE LEVEL: II.

The Outcome of A Centralization Program in Biliary atresia: 20 years and beyond.

OBJECTIVE: Biliary atresia (BA) is a rare disease and reported outcomes of surgical management, typically a Kasai portoenterostomy (KPE), vary considerably across the world. Centralization has been proposed to improve this. SUMMARY BACKGROUND DATA: A national centralization programme was started in Jan. 1999, involving 3 English units with co-located liver transplant facilities. As the program has now reached the 20-year point, the main aim was to update outcome statistics and identify trends. METHODS: Prospective registry and database. The main measures of outcome were (i) time to KPE, (ii) Clearance of Jaundice (CoJ), defined as reaching a bilirubin value of <20µmol/L (≈1.5 mg/dL), and (iii) actuarial native liver survival (NLS) and overall survival (OS). Data are quoted as median (IQR) and non-parametric statistical comparison used with P<0.05 regarded as significant. RESULTS: 867 infants were born with BA and managed between January 1999 and December 2019. Death occurred without intervention (n=10, 1.1%) or were subject to primary transplant (n=26, 3.0%); leaving 831 (95.9%) infants who underwent KPE at median age of 51 (IQR 39-64) days. Age at KPE reduced over the period (P=0.0001) becoming 48(35-57) days in the last 5-year era. CoJ was achieved in 505/831 (60.6%), also increasing over the period (P=0.002). 42 (5.0%) died post-KPE and 384 were transplanted, leaving 405 alive with their native livers at last follow-up. Of the 412 children transplanted, there were 23 (5.6%) deaths, leaving 387 alive. 5-year and 10-year native liver survival were 51.3% (95% CI 54.8-47.8) and 46.5% (95% CI 50.1 - 42.9) and overall survival were 91.5% (95% CI 93.2 - 89.4) and 90.5% (95% CI 92.3 - 88.2%) respectively. CONCLUSIONS: There have been continued improvements in efficiency over the period of centralization with a significant reduction in time to KPE and improved CoJ following KPE. Overall survival in this disease remains >90%.

The AST-to-Platelet Ratio Index (APRi) at Kasai Portoenterostomy: Standing the Test of Time.

AIMS: The outcomes following surgical treatment of infants with biliary atresia (BA) varies across the world with many possible confounding factors. APRi (AST-to-platelet ratio index) is a simple surrogate marker of liver fibrosis and we sought to determine its long-term relationship (if any) with outcome post-Kasai portoenterostomy (KPE). METHODS: Prospectively acquired database (Jan 1998-Dec 2021). Clearance of jaundice was defined as achieving <20 umol/L post-KPE. Categorical and survival data were tested using Chi2 tests and a log rank test respectively. P ≤ 0.05 was regarded as significant. Data are quoted as median (interquartile range) unless otherwise stated. RESULTS: There were 473 infants with a calculated APRi at time of KPE [0.70 (IQR 0.45-1.2)] and known outcomes. There was significant but moderate correlation with age at KPE (rS = 0.43; P < 0.0001). APRi was divided into quartiles (1st 0.11-0.44, n = 120; 2nd 0.45-0.69, n = 120; 3rd 0.70-1.18, n = 115 and 4th 1.2-15.1; n = 118). There was a clear distinction in APRi levels between CMV + ve BA and the other groups (Syndromic BA, Cystic BA, Isolated BA), with an overrepresentation of CMV IgM + ve BA in the higher APRi quartiles (Χ2 = 26.6; P = 0.0002). Clearance of jaundice showed a stepwise decrease across the quartiles (67%; 58%; 55%; 49%; overall Χ2 = 7.8, P = 0.049 and P = 0.005 for trend). Decreasing native liver survival also showed a significant trend (P = 0.01). CONCLUSION: APRi appears to be of fundamental prognostic value in stratifying the BA population. In our series, CMV status was associated with higher APRi score and appears to be different. This simple variable offers an objective method of assessing the biological status of BA at presentation and variability between different series. LEVEL OF EVIDENCE: II (prospective comparison).

Advances in understanding of biliary atresia pathogenesis and progression - a riddle wrapped in a mystery inside an enigma.

INTRODUCTION: Biliary atresia is a potentially fatal condition of the bile ducts - both intra- and extrahepatic, for which we have no cure. Though principally a cholestatic condition, much of its pathology stems from its tendency to aggressively induce liver fibrosis and ultimately cirrhosis, only partially restrained by the portoenterostomy. AREAS COVERED: This review is based on the current literature exploring the heterogeneous nature of biliary atresia. Thus, there are various phenotypes or variants of biliary atresia, each potentially with different etiological backgrounds caused by a number of hypothetical pathological mechanisms thought to be important in the genesis of the condition. Search methodology: the review (Oct. - Nov. 2022) is based on a search of PubMed (NLM) using main keyword 'biliary atresia' with supplementary searches using 'fibrosis'; 'inflammation'; 'BASM'; 'genetics'; 'surgery'; 'experimental'; 'etiology'; 'virology'; 'cases'; and 'syndromes.' EXPERT OPINION: Future developments will be made on matching clinical variants with a more distinct pathophysiological discrimination and those pathways linking the initial cholestatic phase of biliary atresia to the early stages of fibrosis.

Historical and Contemporary Management of Infantile Hepatic Hemangioma: A 30-year Single-center Experience.

OBJECTIVE: To describe outcome of infants with hemangioma(s) of the liver. SUMMARY OF BACKGROUND DATA: Infantile hepatic hemangiomas exhibit a diverse phenotype. We report our 30-year experience and describe optimal management based on precise radiological classification. METHODS: Retrospective review of 124 infants (66 female) 1986-2016. Categorical analysis with Chi2 and nonparametric comparison. Data expressed as median (range) and P < 0.05 considered significant. RESULTS: Lesions classified as focal (n = 70, 56%); multifocal (n = 47, 38%) or diffuse (n = 7, 6%) and of these 80(65%) were symptomatic (eg, cardiac failure n = 39, 31%; thrombocytopenia n = 12, 10%).Increased hepatic artery velocity was seen in 63 (56%). Median hepatic artery velocity was greatest in diffuse lesions [245 (175-376) cm/s vs focal 120 (34-242) cm/s vs multifocal 93 (36-313) cm/s; P = 0.0001]. Expectant management alone was followed in 55 (44%). Medical therapy was utilised in 57(46%) and sufficient for symptom control in 29/57 (51%). Propranolol therapy (from 2008) was sufficient for symptom control in 22/28 (79%). Surgery (hepatic artery ligation n = 26; resection n = 13; embolization n = 1) was required in 40 (32%). Median maximal lesion diameter was 3 (0.5-17.1) cm and greater in those requiring surgery (7 cm vs 4.9 cm; P = 0.04). The proportion requiring surgery decreased markedly in the propranolol era [pre-propranolol 25/48 (52%) vs post-propranolol 16/76 (21%) (P = 0.0003)]. Systematic follow-up with ultrasound to a median of 2.6 (0.02-16) years. CONCLUSIONS: A proportion of infantile hepatic hemangiomas remain asymptomatic permitting observation until resolution but the majority require complex multi-modal therapy. First-line pharmacotherapy with propranolol has reduced but not abolished the need for surgery.

At risk child: a contemporary analysis of injured children in London and the South East of England: a prospective, multicentre cohort study.

Background: Injury is a leading health burden in children yet relatively little is reported about the contemporary risks they face. Current national registry data may under-represent the true burden of injury to children. We aim to analyse contemporary patterns of paediatric trauma and identify current factors putting children at risk of injury. Methods: A 3-month prospective multicentre cohort evaluation of injured children across the London Major Trauma System was performed. All children receiving a trauma team activation; meeting National Institute for Health and Care Excellence CT head criteria; or admitted/transferred out due to trauma were included. Data were collected on demographics, mechanism and location of injury, and body region injured. The primary outcome was in-hospital mortality and secondary outcome was safeguarding concerns. Results: 659 children were included. Young children were more likely to be injured at home (0-5 years old: 70.8%, n=167 vs adolescents: 15.6%, n=31). Adolescents were more likely to be injured in the street (42.7%, n=85). Head trauma caused over half of injuries in 0-5 years old (51.9%, n=121). Falls were common and increasingly prevalent in younger children, causing 56.6% (n=372) of injuries. In adolescents, penetrating violence caused more than one in five injuries (21.9%, n=50). Most injured children survived (99.8%, n=658), however, one in four (26.1%, n=172) had safeguarding concerns and a quarter of adolescents had police, third sector or external agency involvement (23.2%, n=53). Conclusions: This study describes modern-day paediatric trauma and highlights the variance in injury patterns in young children and adolescents. Importantly, it highlights differences in actual rates of injuries compared with those reported from current national registry data. We must understand real risks facing 21st century children to effectively safeguard future generations. The results provide an opportunity to reassess the current approach to injury prevention, child and adolescent safeguarding, and public health campaigns for child safety.

Prediction of Mortality in Newborn Infants With Severe Congenital Diaphragmatic Hernia Using the Chest Radiographic Thoracic Area.

OBJECTIVES: To evaluate whether the preoperative chest radiographic thoracic area in newborn infants with congenital diaphragmatic hernia was related to the length of mechanical ventilation and the total length of stay and whether chest radiographic thoracic area predicted survival to discharge from neonatal care. DESIGN: Retrospective observational cohort study. SETTING: Tertiary neonatal unit at King's College Hospital National Health Service Foundation Trust, London, United Kingdom. PATIENTS: Newborn infants admitted with congenital diaphragmatic hernia at King's College Hospital in a 10-year period (2007-2017). INTERVENTIONS: The chest radiographic thoracic area was assessed by free hand tracing of the perimeter of the thoracic area as outlined by the diaphragm and the rib cage and excluded the mediastinal structures and abdominal contents in the thorax and calculated using the Sectra PACS software (Sectra AB, Linköping, Sweden). MEASUREMENTS AND MAIN RESULTS: Eighty-four infants with congenital diaphragmatic hernia (70 left-sided) were included with a median (interquartile range) gestation of 36 weeks (34-39 wk). Fifty-four (64%) survived to discharge from neonatal care. In the infants who survived the chest radiographic thoracic area was not related to the length of mechanical ventilation (r = 0.136; p = 0.328) or the total duration of stay (r = 0.095; p = 0.495). The median (interquartile range) chest radiographic thoracic area was higher in infants who survived (1,780 mm [1,446-2,148 mm]) compared with in the deceased infants (1,000 mm [663-1,449 mm]) after correcting for confounders (adjusted p = 0.01). Using receiver operator characteristics analysis, the chest radiographic thoracic area predicted survival to discharge from neonatal care with an area under the curve of 0.826. A chest radiographic thoracic area higher than 1,299 mm predicted survival to discharge with 85% sensitivity and 73% specificity. CONCLUSIONS: The chest radiograph in infants with severe congenital diaphragmatic hernia can predict survival from neonatal care with high sensitivity and moderate specificity.

Pediatric adrenal trauma: evaluation and follow-up with contrast-enhanced ultrasound (CEUS).

Adrenal trauma is rarely encountered in the pediatric population, often as a component of multi-organ injury and often presenting with hematoma formation. Contrast-enhanced computed tomography (CECT) is the established imaging modality both for initial evaluation and follow-up of patients with blunt abdominal trauma. In children, radiation exposure should be minimized and alternative imaging strategies are needed. Contrast-enhanced ultrasound (CEUS) has recently been successfully used for evaluation of patients with hepatic, renal and splenic injury. We present three cases of children with post-traumatic adrenal hematomas, which were initially diagnosed with CECT and subsequently followed up with CEUS, suggesting that CEUS may be considered for follow-up of adrenal injuries in children. CEUS improves the diagnostic capabilities by increasing tissue contrast and spatial resolution, readily differentiating viable from necrotic tissue in comparison to conventional ultrasound without the risk of iodine contrast agents and ionizing radiation of repeated CECT examinations.

3D printing to simulate laparoscopic choledochal surgery.

AIMS OF THE STUDY: Laparoscopic simulation has transformed skills acquisition for many procedures. However, realistic nonbiological simulators for complex reconstructive surgery are rare. Life-like tactile feedback is particularly difficult to reproduce. Technological innovations may contribute novel solutions to these shortages. We describe a hybrid model, harnessing 3D technology to simulate laparoscopic choledochal surgery for the first time. METHODS: Digital hepatic anatomy images and standard laparoscopic trainer dimensions were employed to create an entry level laparoscopic choledochal surgery model. The information was fed into a 3D systems project 660pro with visijet pxl core powder to create a free standing liver mold. This included a cuboid portal in which to slot disposable hybrid components representing hepatic and pancreatic ducts and choledochal cyst. The mold was used to create soft silicone replicas with T28 resin and T5 fast catalyst. The model was assessed at a national pediatric surgery training day. RESULTS: The 10 delegates that trialed the simulation felt that the tactile likeness was good (5.6/10±1.71, 10=like the real thing), was not too complex (6.2/10±1.35; where 1=too simple, 10=too complicated), and generally very useful (7.36/10±1.57, 10=invaluable). 100% stated that they felt they could reproduce this in their own centers, and 100% would recommend this simulation to colleagues. CONCLUSION: Though this first phase choledochal cyst excision simulation requires further development, 3D printing provides a useful means of creating specific and detailed simulations for rare and complex operations with huge potential for development.

Post-traumatic liver and splenic pseudoaneurysms in children: Diagnosis, management, and follow-up screening using contrast enhanced ultrasound (CEUS).

BACKGROUND: Pseudoaneurysm (PA) formation following blunt and penetrating abdominal trauma is a recognized complication in solid organ injury, usually diagnosed by contrast-enhanced CT (CECT) imaging. Delayed rupture is a potentially life-threatening event, although its frequency is not known in pediatric trauma. Contrast enhanced ultrasound (CEUS) is a novel radiation-free alternative to CECT with the potential to identify PA. METHODS: A retrospective review of consecutive cases of significant liver and splenic injuries admitted to single institution (tertiary and quaternary referrals) over more than a 12year period was performed. From 2011, CEUS was performed routinely postinjury (5-10days) using SonoVue™ as contrast. Initially, CECT and CEUS were performed in tandem to ensure accurate correlation. RESULTS: From January 2002-December 2014, 101 (73M) children [median age was 14.2 (1.3-18)years] with liver and splenic injuries were admitted. Injuries included: liver [n=57, grade 3 (1-5)], splenic [n=35, grade 3 (1-5)], and combined liver/spleen [n=8, (1-4)]. Median Injury Severity Score (ISS) was 13 (2-72). The predominant mechanisms of injury were blunt trauma n=73 (72%) and penetrating trauma n=28 (28%). Seventeen children (17%) developed PA. Six children became symptomatic (35%), and five went on to have embolization [at 7 (3-11)days]. These were detected by CECT (n=4) and CEUS (n=2). Eleven children remained asymptomatic [detected by CECT (n=8) and CEUS (n=3) at median 5 (4-8)days]. One underwent embolization owing to evidence of interval bleeding. Sensitivity of CEUS at detection of PA was 83%, with specificity of 92% (PPV=71%, NPV=96%). There was no association between grade of injury and presence of PA in either liver or splenic trauma (P=0.4), nor was there an association between size of PA and symptoms (P=0.68). Children sustaining splenic PA were significantly younger than those with hepatic PA (P=0.03). Follow-up imaging confirmed resolution of PA in 16 cases. One child was lost to follow-up. CONCLUSIONS: The incidence of PA is higher than previously reported in the pediatric literature (<5%). Postinjury imaging appears mandatory, and CEUS appears to be highly sensitive and specific for diagnosis and follow-up.

Aspartate Aminotransferase-to-Platelet ratio index (APRi) in infants with biliary atresia: prognostic value at presentation.

BACKGROUND: Biliary atresia (BA) is a progressive obliterative cholangiopathy leading to liver fibrosis and cirrhosis. The aspartate aminotransferase-to-platelet ratio index (APRi) has been used in other liver diseases and in older children with BA as a surrogate marker of liver fibrosis. The aim of this study was to calculate APRi at time of presentation and relate this to operative findings and early outcome. METHODS: Prospective single surgeon cohort study of infants with BA (January 1999-December 2010). Initial APRi values were related to other biochemical indices and liver appearance at the time of Kasai portoenterostomy. Data are expressed as median (interquartile range). Non-parametric comparison was performed and a P-value of≤0.05 was regarded as significant. RESULTS: Overall 260 infants were included in the study. Median APRi was 0.67 (0.43-1.12) at a median age of surgery of 58 (range 14-209) days. APRi correlated with age (rs=0.44; P<0.0001), spleen size (rs=0.48; P<0.0001) and bilirubin (rs=0.45; P<0.0001). Liver assessment at operation was divided into cirrhosis [n=28 (10.8%)] or non-cirrhosis. Using a cut-off value of 1.22 [AUC 0.83 (95% CI 0.73-0.90)] showed a sensitivity of 75% and a specificity of 84% for macroscopic cirrhosis. Native liver survival was significantly different but improved only for those in the lowest APRi quartile (<0.43; P<0.009). APRi values at presentation had no significant association with later development of significant oesophageal varices. CONCLUSION: APRi at the time of KP is a useful adjunct in evaluating severity of liver disease in BA at presentation.

Gallstone disease in children.

Gallstone disease in children is evolving, and for the previous 3 decades, the frequency for surgery has increased greatly. This is in part because of improved diagnostic modalities, but also changing pathology, an increased awareness of emerging comorbidities, such as childhood obesity, and other associated risk factors. This article outlines the pathophysiology, genetics, and predisposing factors for developing gallstones and includes a review of the literature on the current and more novel medical and surgical techniques to treat this interesting disease.

Pancreatic pseudocysts in children: treatment by endoscopic cyst gastrostomy.

AIM: The aim of the present study was to review the use of endoscopic cyst gastrostomy (E-CG) as a treatment option for pancreatic pseudocysts referred to a tertiary paediatric surgical centre. METHODS: Retrospective review during a 10-year period (January 2001-December 2010). Cyst gastrostomies were performed using 1 or 2 double pigtailed Zimmon stents (7-10 Fr) under general anaesthesia. Data are quoted as median (range). RESULTS: E-CG was performed in 7 (5 males) children (median age at presentation 11.7 [8.2-15.8] years). Pancreatic pseudocysts were caused by acute pancreatitis in 5 (gallstones n = 1, hereditary pancreatitis n = 1, pancreatic divisum n = 1, asparaginase induced n = 1, and idiopathic n = 1) and pancreatic trauma in 2 (motor vehicle accident n = 1, and handlebar injury n = 1). All of the cases were associated with a rise in serum amylase level, median 1028 (276-2077) IU/L at the peak of symptoms. Three children had pancreatic duct stent placement during endoscopic retrograde cholangiopancreatography as the initial therapeutic intervention, but went on to have E-CG later. One who had a huge pseudocyst at presentation had already undergone an open cyst gastrostomy, which had recurred at 1 month. Rescue E-CG was performed 38 days later. All of the stents were removed endoscopically at 8 (6-40) weeks. E-CG was uncomplicated and pseudocysts resolved completely in 5. One required repeat placement at 15 days due to catheter slippage with later full resolution. One child required open cyst gastrostomy due to reaccumulation two months following removal of the stent. Median hospital stay post E-CG was 3 (1-23) days. There has been no recurrence at median follow-up of 18 (5-108) months. CONCLUSIONS: Endoscopic cyst gastrostomy is a safe and effective alternative for the management of pancreatic pseudocysts in children and should now be considered as treatment of choice.

Portal venous pressure in biliary atresia.

UNLABELLED: Biliary atresia (BA) is characterized by a variable degree of fibrosis within the liver, causing portal hypertension sometimes evident at the time of presentation. AIM: The aims of this study are to measure portal venous pressure (PVP) at time of Kasai portoenterostomy (KP) and to investigate the value of surrogate indices. METHODS: At the time of KP and before any liver manipulation, an attempt was made to recanalize the umbilical vein, allowing a catheter to be sited. Preoperative noninvasive variables included maximum splenic diameter (on ultrasound); platelet count, aspartate aminotransferase, and bilirubin; and the aspartate aminotransferase/platelet index ratio (APRi). Clearance of jaundice was defined as achieving a bilirubin of less than 20 µmol/L. Data are quoted as median (range). Nonparametric statistical tests were used, and P < .05 was regarded as significant. RESULTS: Portal venous pressure measurements were available in 61 infants, who underwent a KP during the period February 2007 to October 2010. Median age at KP was 52 (19-151) days. Median PVP was 9 (3-26) mm Hg and was significantly lower in those with isolated (n = 47) BA vs cytomegalovirus-associated BA (n = 6) (8 vs 17 mm Hg; P = .02). Overall, PVP correlated with spleen size (r(s) = 0.38; P < .0001), APRi (r(s) = 0.5; P < .0001), bilirubin (r(s) = 0.38; P = .001), and age at KP (r(s) = 0.33; P = .0004). Thirty-three infants (56%) cleared their jaundice (to <20 µmol/L). There was no significant difference in median PVP (7 vs 9.5 mm Hg; P = .1) between these groups. To date, 6 children have undergone endoscopy, with 2 requiring intervention for significant varices. Neither infant at time of KP had elevated PVP (3 and 9 mm Hg). CONCLUSIONS: Portal venous pressure is a key variable in the assessment of the BA liver, and differences can be shown depending on underlying cause (eg, cytomegalovirus status). Furthermore, it has modest correlation with noninvasive indices (eg, spleen size and APRi) but appears of limited use when used as prognostic index of outcome and indeed in the later development of varices.

Understanding choledochal malformation.

Choledochal malformations (also known as choledochal cysts) may be characterised as an abnormal dilatation of the biliary tract, in the absence of any acute obstruction. Most appear to be of congenital origin probably related to distal bile duct stenosis, and almost 15% can now be detected antenatally. Excision and biliary reconstruction using a Roux loop as an open operation is still the standard to compare to. This article discusses recent advances in the understanding of their aetiology and classification together with the place of newer modalites of surgical treatment such as laparoscopic excision and biliary reconstruction. Although these are definitely feasible and safe, care should be taken before dispensing with standard open techniques which have minimal complications and proven long-term benefit.

The predictive value of a repeat micturating cystourethrogram for remnant leaflets after primary endoscopic ablation of posterior urethral valves.

OBJECTIVE: We routinely perform a cystourethroscopy 3 months after initial ablation of posterior urethral valves. The aim of this study was to determine the predictive value of the urethral appearance on preoperative micturating cystourethrogram (MCUG) for further valve resection at check cystoscopy. PATIENTS AND METHODS: We retrospectively reviewed 31 consecutive boys (aged 4-18 months) who underwent check cystoscopy and repeat MCUG between 2006 and 2008. RESULTS: Repeat MCUG suggested remnant valves in 10, but no residual leaflets were identified cystoscopically in 4. In 20 boys, the valves appeared completely ablated on MCUG but valve leaflets received further resection in 10. One study was undiagnostic. Residual valves were resected in 83% (5/6) where valves and urethral dilatation were noted on MCUG. Where MCUG suggested either valves or persistent dilatation alone, further resection occurred in 40% (4/10). Remnant leaflets were also present in half of those (7/14) in whom the repeat MCUG had shown complete ablation and resolved/reduced posterior urethral dilatation. CONCLUSIONS: The positive predictive value of valve leaflets and/or posterior urethral dilatation on repeat MCUG for subsequent resection of valve remnants was 56%; the negative predictive value was 50%. We found repeat MCUG alone imprecise in excluding residual valve tissue and recommend check cystoscopy in all.