The early effects of urinary tract obstruction on glomerulogenesis

Purpose

Our obstructive uropathy model in fetal lambs showed that renal cystic changes appeared 3 weeks after obstruction. In this study, the authors investigated the changes resulting from complete urinary tract obstruction in the first 7 days after obstruction.

Methods

An obstructive uropathy was created in fetal lambs at 60 days’ gestation by ligating the urethra and urachus. They were delivered 48 hours, 3 days, 5 days, and 7 days later by cesarian section. The kidneys were removed and processed for histologic examination.

Results

Eighteen fetuses were operated on and 15 (4 at 48 hours, 4 at 3 days, 2 at 5 days, and 5 at 7 days; 83%) survived. Macroscopically, bladder dilatation and slightly dilated ureters were identified from 48 hours. Microscopically, dilatation of proximal tubules started from 48 hours after obstruction and increased by 7 days. Glomerular cysts in the nephrogenic zone also were identified from 48 hours. Dysplastic changes were not found.

Conclusions

The first areas in the developing kidney that suffer damage after obstructive uropathy are the proximal tubule and the nephrogenic zone. This change started 48 hours after obstruction. Shunting procedures need to be performed considerably earlier than previously thought.     

Enteric duplications presenting as antenatally detected abdominal cysts: is delayed resection appropriate?

Purpose: The aim of this study was to evaluate delayed elective resection of antenatally detected enteric duplication cysts.Methods: A retrospective casenote study of intraabdominal cysts detected antenatally between January 1991 and January 2002 found 37 fetuses with cysts. Twelve were enteric duplications. Two were duodenal, 1 was an 85-cm tubular jejunoileal duplication, and 9 were ileocecal. Asymptomatic cysts were followed with serial ultrasound scars and resected electively over 14 months.Results: Three neonates had small bowel obstruction demanding laparotomy: 1 of the 2 infants with duodenal duplication cysts, 1 infant with an ileocecal duplication, and the infant with the tubular duplication. One with an ileocecal duplication became symptomatic at 2 months and underwent a laparotomy. Seven had their duplications resected electively between 6 weeks and 14 months, and the other is still being followed. Four of the 7 asymptomatic duplications electively resected contained gastric mucosa.Conclusions: Intraabdominal enteric duplication cysts are increasingly likely to be detected antenatally. The majority are likely to remain asymptomatic for several months at least, after which a resection can be planned. The prevalence of gastric mucosa suggests that they should not be left indefinitely. Laparoscopically assisted resection of ileocecal duplications is safe and effective.     

Multiple intrahepatic biliary cysts in children with biliary atresia

Purpose: The aim of this study was to investigate the incidence, clinical course, and outcome of multiple intrahepatic biliary cysts in patients with biliary atresia. Methods: From 1992 to 2000, 154 patients with biliary atresia were examined for intrahepatic cysts. They were followed and examined routinely using abdominal ultrasonography. Results: Twenty-three patients had single intrahepatic cysts, and 16 patients had multiple cysts. The incidence of intrahepatic cysts in these patients were 25.3% (39 of 154) for all kinds of cysts and 10.4% (16 of 154) for multiple intrahepatic cysts. Of the 16 patients with multiple cysts, 13 (81.3%) had jaundice, and 15 (93.8%) had a history of cholangitis before cysts were detected. Image studies showed multiple discrete ovoid or round intrahepatic biliary cysts with various sizes along the biliary trees. The cysts decreased in size or number in 7 patients after antibiotic treatment and disappeared in only one patient. The mortality rate was higher in patients with multiple cysts than in those with single cysts (P = .037). Conclusions: Multiple intrahepatic biliary cysts are a common complication in patients with biliary atresia and suggests a poor prognosis. Prolonged parenteral antibiotics treatment should be administered when signs of biliary infection appear. J Pediatr Surg 37:1183-1187.     

Effects of partial liquid ventilation on cerebral blood flow and cerebral metabolism in neonatal lambs

Background/Purpose: Liquid ventilation is a promising therapy for respiratory failure. The effects of perfluorochemical on cardiac output have not been well described. The purpose of this study was to compare cerebral blood flow (Q_CAROTID) and cerebral metabolic rates (CMR) during conventional ventilation (CV) and partial liquid ventilation (PLV). Methods: Five 2-week-old lambs underwent tracheostomy and central venous, aortic, and postcerebral venous catheter placement. Doppler flow probes were placed around the common ovine trunk, and the lambs underwent CV for 1 hour. Ventilation was adjusted to maintain physiologic blood gases. Pre- and postcerebral blood gas, glucose, and lactate samples were obtained every 15 minutes. Perfluorodecalin then was instilled endotracheally. The lambs underwent 1 hour of PLV with similar sampling. Data were analyzed using the Wilcoxon matched pairs test, significance at P [le ] .05. Results: The authors observed no difference in mean Q_CAROTID or carotid vascular resistance between CV and PLV (P = .35 and .34, respectively). The CMR of oxygen, glucose, and lactate were calculated using the Fick principle. CMR was unchanged between modes (P = .5). Conclusions: PLV did not adversely alter Q_CAROTID or CMR in lambs, implying that this mode of ventilation should be safe in neonatal patients at risk for neurologic injury. J Pediatr Surg 37:840-844.     

Gastric smooth muscle contractility changes in the esophageal atresia rat model: an in vitro study

Purpose: The aim of the study was to investigate the gastric smooth muscle reactivity in the Adriamycin-induced esophageal atresia (EA) rat model.Methods: The fetuses were divided into 3 groups. The control group was exposed to saline. The second group was comprised of fetuses that were exposed to Adriamycin but did not have EA (Adriamycin-no-EA group). The third group was comprised of fetuses that were exposed to Adriamycin and had EA (Adriamycin-EA group). Gastric fundus strips were studied in vitro for their contractile response to receptor activation in the 3 groups.Results: Contractile responses of gastric smooth muscle to carbachol and KCl were increased in the Adriamycin-EA group compared with the Adriamycin-no-EA group. Also serotonin-induced contractile response in the Adriamycin-EA group decreased compared with the Adriamycin-no-EA group. Relaxation of gastric smooth muscle strips to isoproterenol was comparably unaffected in the Adriamycin-EA and Adriamycin-no-EA groups. Likewise, no change in the response to agonist studies was observed between the control and Adriamycin-no-EA groups. The relaxant response to papaverine was not different in the 3 groups.Conclusions: This study found changes of receptor-dependent and receptor-independent contraction of the gastric fundus smooth muscle in the fetuses with EA. Therefore, impaired contractile responses may be, at least in part, a contributing factor in the abnormal gastric motility seen in EA.     

Fetal tissue engineering: in utero tracheal augmentation in an ovine model

Background/Purpose: This study was aimed at comparing fetal tissue engineering with autologous free grafting in an ovine model of in utero tracheal repair. Methods: Chondrocytes were isolated from both elastic and hyaline cartilage specimens harvested from fetal lambs and expanded in vitro. Cells were seeded dynamically onto biodegradable scaffolds, which then were maintained in a rotating bioreactor for 6 to 8 weeks. Constructs subsequently were implanted into fetal tracheas (n = 15), in a heterologous fashion (group I). In group II, fetuses (n = 5) received autologous free grafts of elastic cartilage harvested from the ear as tracheal implants. In vivo specimens were harvested for histologic analysis at different time-points postimplantation. Results: In the 12 of 15 surviving fetuses of group I, all constructs were found to resemble normal hyaline cartilage, engraft well despite their heterologous origin, and display time-dependent epithelialization derived from the native trachea. All autologous free grafts were engrafted and epithelialized at birth, retaining histologic characteristics of elastic cartilage, but were more deformed than engineered constructs. Of the lambs allowed to reach term, 5 of 5 in the engineered group and 4 of 5 in the free graft group could breathe spontaneously. Conclusions: (1) Tissue-engineered cartilage, as well as autologous free grafts, can be implanted successfully into the fetal trachea, resulting in engraftment and function. (2) Engineered cartilage provides enhanced structural support after implantation into the fetal trachea when compared with free grafts. Prenatal tracheoplasty may prove useful for the treatment of severe congenital tracheal malformations. J Pediatr Surg 37:1000-1006.     

Minimally invasive management of the prenatally torsed ovarian cyst

Background: Fetal and neonatal ovarian cysts are detected frequently by ultrasonography. The presence of these lesions can result in adnexal torsion in utero with autoamputation. Historically, these have been removed at laparotomy. Methods: Retrospective chart review was performed at a single children's hospital from October 1996 to September 2001. Results: Six cases of torsion of ovarian cysts were removed laparoscopically. Five of the 6 patients had prenatal ultrasound diagnosis. The sixth had the cyst detected incidentally by magnetic resonance imaging (MRI) at 3 months of age. All cysts were complex by ultrasound criteria. All 6 procedures were performed via a 2-port laparoscopic approach. The average age at surgery was 3.7 months (range, 9 days to 7.5 months). There were no postoperative complications. Five patients were discharged on the day of surgery. Conclusion: Laparoscopy offers a safe, effective, and cosmetic means of managing perinatal torsion of ovarian cysts. J Pediatr Surg 37:1467-1469.     

Deficient motor innervation of the sphincter mechanism in fetal rats with anorectal malformation: a quantitative study by fluorogold retrograde tracing

Background/purpose: Deficiency of motoneuron innervation to the sphincter mechanism has been described in patients with anorectal malformation. Whether this event is primary or secondary remains unclear.Methods: The authors quantified the motoneuron innervation of the sphincter mechanism by Fluorogold (FG) retrograde tracing experiment in fetal rats with anorectal malformation. Anorectal malformation was induced in rat fetuses by ethylenethiourea (ETU). Serial longitudinal sections encompassing the whole width of lumbosacral spinal cord were examined. The number of FG-labelled motoneurons were scored and compared between male fetuses with or without malformation in the ETU-fed group and normal controls.Results: The number of FG-labelled motoneurons in the fetuses without defect, with imperforate anus (IA), with neural tube anomalies (NTA), with combined IA and NTA, and normal controls were determined to be (mean ± SEM) 109.13 ± 37.88, 55.05 ± 25.85, 48.20 ± 30.34, 54.43 ± 28.55, and 135.22 ± 28.78, respectively. FG-labelled motoneurons in the fetuses with IA, NTA, and combined IA and NTA are significantly fewer than that in fetuses without defects (P < .05) and in normal controls (P < .005).Conclusions: These findings suggest that defective motoneuron innervation to the sphincter mechanism is a primary anomaly that coexists with the alimentary tract anomaly in anorectal malformation during fetal development. The intrinsic neural deficiency is an important factor likely to contribute to poor postoperative anorectal function despite surgical correction of anorectal malformation.     

Positive intrapulmonary oncotic pressure enhances short-term lung growth acceleration after fetal tracheal occlusion

Purpose: This study was aimed at determining whether positive oncotic pressure induced in the fetal lung liquid could safely maximize accelerated lung growth after tracheal occlusion. Methods: Fetal lambs (n = 21) were divided into 4 groups: group I (n = 5) consisted of sham-operated controls; group II (n = 5) underwent simple tracheal occlusion (TO); group III (n = 5) received TO and 60 mL of saline injected into the trachea; and group IV (n = 6) underwent TO and intratracheal infusion of 60 mL of iso-osmotic, 6% Dextran 70. All fetuses were delivered near term, at a mean of 15.9 [plusmn] 1 days postoperatively. Their lungs were studied by standard morphometric techniques, and the basic chemical profile of the lung liquid was analyzed. Statistical comparisons were by 1-way analysis of variance (ANOVA) and post-hoc analyses by the Bonferroni correction for multiple comparisons, with P values less than .05 considered significant. Results: The lung volume-to-body-weight ratio (LV:BW) was significantly different among groups. Pairwise comparisons of LV:BW showed that it was higher in group IV than in all other groups, but there was no difference between groups II and III. Airspace fraction was not significantly different among groups, and histologic appearance was normal in all lung samples. There were no differences in lung liquid osmolarity, pH level, and electrolyte concentrations. Conclusion: Positive intrapulmonary oncotic pressure by an isosmotic agent boosts short-term lung growth acceleration after fetal tracheal occlusion with no evidence of cell damage. J Pediatr Surg 37:1007-1010.     

The management of fetal ovarian cysts

Background/Purpose: Ovarian torsion causing the loss of an ovary represents the most common complication of fetal ovarian cysts and occurs more frequently before than after birth. Thus, treatment of fetal simple ovarian cysts should be performed antenatally; however, criteria for prenatal decompression still need to be evaluated. Previous experience of the authors showed that large simple cysts have a poor outcome, whereas preliminary attempts of their [ldquo ]in utero[rdquo ] aspiration were all successful and uneventful. The authors evaluated the outcome of fetal simple ovarian cysts after prenatal aspiration and considered criteria for this procedure. The outcome of cysts showing a prenatal ultrasound pattern of torsion also was studied. Methods: This prospective study includes 73 ovarian cysts (48 simple, 25 showing torsion) diagnosed in 72 fetuses from June 1992 to June 1999, and followed up until spontaneous resolution or surgery. Prenatal aspiration was performed in the case of simple cysts [ge ]5 cm in diameter. The outcome of these cysts was compared with that of similar cysts not aspirated in the authors' previous study ([Chi ]²).¹⁰ Cysts with an US pattern of torsion persisting at birth were operated on. The outcome of simple cysts less than 5 cm and cysts with a prenatal ultrasound appearance of torsion also was evaluated. Results: Prenatal decompression was performed without any complications in 14 cases: 12 (86%; 95% CI: 0.68 to 1.00) regressed subsequently; 2 (14%; 95% CI: 0.00 to 0.32) showed torsion postnatally. This outcome is significantly better than that of similar cysts not aspirated in the authors' previous study¹⁰ (P = .0002). Among the 34 simple cysts less than 5 cm, 26 (76%; 95% CI: 0.62 to 0.90) resolved spontaneously; 8 (24%; 95% CI: 0.10 to 0.38) had complications, 7 of which showing torsion (diameter at evidence of torsion, 4.4 cm [median]; range, 3.3 to 5.2 cm). Among the 34 cysts showing torsion (25 with initial US pattern of torsion + 9 subsequently complicated simple cysts), 24 (71%; 95% CI: 0.56 to 0.86) required oophorectomy; 9 (26%; 95% CI: 0.11 to 0.41) spontaneously disappeared at ultrasound, one of which required surgery for intestinal obstruction secondary to adhesion of a necrotic ovary; one patient (3%; 95% CI: 0.00 to 0.09) was lost to follow-up. Conclusions: Prenatal aspiration of ovarian cysts appears effective and safe: a [ldquo ]cutoff[rdquo ] of 4 cm should be investigated. Cysts with ultrasound pattern of torsion persisting postnatally require surgery; options for their management, when sonographically disappearing and asymptomatic, need to be investigated.     

Laparoscopic duodenoduodenostomy for duodenal obstruction in infants and children

Background/Purpose: Duodenal obstruction, such as that resulting from atresia or web, routinely has been corrected by laparotomy and duodenoduodenostomy. Until recently, no one has reported on the use of minimally invasive techniques to correct this congenital anomaly. Over the last 6 months we have approached 4 patients, 3 with atresia and one with a web, laparoscopically. Three were newborns, and one was 8 months old. Methods: All procedures were performed with 3-mm instruments and scopes. Results: Operating time in all cases was less then 90 minutes. Visualization was excellent, and there were no intraoperative complications. Feedings were started on postoperative day 5 in all 3 neonates and day 3 in the infant. All 4 were on full feedings after 3 days. Follow-up upper gastrointestinal tests show no evidence of stricture or obstruction. Conclusion: Laparoscopy provides an excellent way to evaluate and treat congenital duodenal obstruction. J Pediatr Surg 37:1088-1089.     

Bladder development following bladder outlet obstruction in fetal lambs: optimal timing of fetal therapy

Background

Lower urinary tract obstruction causes both renal failure and bladder dysfunction after birth. This study examined the early bladder wall changes after creating an obstructive uropathy focusing on bladder wall thickness and muscle integrity.

Methods

We created obstructive uropathy in fetal lambs at 60 days' gestation, ligating the urethra and urachus. The fetuses (n = 28) were delivered at 48 hours and 3, 4, 5, 7, and 14 days after obstruction and at term (145 days' gestation). Sham-operated lambs were used as controls (n = 20). Histology samples were stained using α-smooth muscle actin) immunohistochemistry and also hematoxylin-eosin, Masson trichrome, and colloidal Fe stain.

Results

The bladder wall initially expanded and stretched. By day 4, the bladder wall became thicker. Histologically, the bladder in obstructed lambs demonstrated a prominent submucosal fibrotic change by 7 days. The mean bladder wall thickness at 14 days after obstruction was thicker than controls, and fibrosis was prominent.

Conclusion

The initial changes in the bladder wall were expansion of the muscle component followed by fibrosis. The bladder wall thickness dramatically increased 4 to 7 days after obstruction. We conclude that shunting operations to preserve bladder function may be needed earlier than expected.     

Wilms' tumor growth is suppressed by antiangiogenic pigment epithelium[ndash ]derived factor in a xenograft model

Background/Purpose: Pigment epithelium[ndash ]derived factor (PEDF), a potent endogenous inhibitor of angiogenesis, is highly expressed in the kidney. The authors postulated that systemic administration of PEDF would decrease Wilms' tumor growth in a xenograft model, and increased renal vascularity would result in a mouse null for PEDF. Methods: Tumors were induced in athymic mice using human anaplastic Wilms' tumor cells. Purified PEDF protein or vehicle was administered for 7 days beginning 2 to 3 weeks after inoculation. Tumors were stained with anti-PEDF and anti[ndash ]Factor VIII antibodies. Mitoses and microvascular density (MVD) were counted per high-power field (hpf). PEDF-null mice were generated on a SV129/C57Bl6 background. Wild-type and null kidneys were assessed for MVD. Results: Mean tumor weight in the 2-week group was 60% less than controls (P [lt ] .05). The MVD and mitotic count in treated tumors were significantly less than controls (P [lt ] .05). PEDF stained strongly in normal kidneys but was minimal to absent in Wilms' tumor. PEDF-null kidneys had increased MVD compared with wild-type (P [lt ] .05). Conclusions: PEDF is expressed strongly in normal murine kidney, and loss of its angioinhibitory activity may contribute to pathologic angiogenesis in Wilms' tumor. Systemic PEDF suppresses WT growth by targeting both the tumor cells and its associated vasculature. J Pediatr Surg 38:336-342.     

The pathogenesis of dysplastic kidney in a urinary tract obstruction in the female fetal lamb

BACKGROUND/PURPOSE: The type of renal dysplasia resulting from obstructive uropathy depends on the completeness of the obstruction and its timing with respect to the stage of glomerulogenesis at the time of the obstruction. The authors created a successful obstructive uropathy model in the female fetal lamb to demonstrate the differing pathogenesis of renal dysplasia. METHODS: Female fetal lambs at 60 and 90 days' gestation had their urethra and urachus ligated transabdominally and were delivered by cesarean section at 145 days (full term). Kidney length and cortical thickness were measured, and samples were examined histologically. In the lambs operated on at 90 days, the urine was collected at delivery and Na and CI were measured and compared with the results obtained from normal full-term lambs. RESULTS: Seven of 10 female lambs had hydronephrosis or dysplastic kidneys. The cortext to kidney length ratio was 10+/-3% in the 90-days hydronephrotic group versus 29+/-6% in the controls (P<.001). Morphologically, the 90-day model had dilatation of the collecting tubules with normal glomerular numbers. The 60-day model had tubular cysts with fibromuscular cuffing and reduced glomerular numbers. The fetal urine Na was 47+/-3.3 mmol/L in controls versus 78+/-24 mmol/L in the hydropnephrotic lambs (P<.05). The urine CI in these lambs was 38+/-8.6 mmol/L in controls versus 55+/-14.5 mmol/L in the hydronephrotic lambs (P<.05). CONCLUSIONS: An obstructive uropathy model was created in female fetal lambs. There were no dysplastic changes in the kidneys in lambs operated on at 90 days' gestation, but there were definite dysplastic changes in those operated on at 60 days. Concentrations of Na and CI in the fetal urine are higher than normal in the 90-day model.     

Resolution of hydrops fetalis in congenital cystic adenomatoid malformation after prenatal steroid therapy

Background/Purpose: Development of hydrops fetalis in fetuses with congenital cystic adenomatoid malformations (CCAM) is a significant risk factor for fetal or neonatal demise. In rare cases, resolution of CCAM has occurred, presumably owing to lesion maturation or involution. Steroid therapy, utilized for lung maturity, has been postulated to accelerate this process. The natural history of hydropic fetuses with CCAM after receiving steroid therapy is presented. Methods: The authors prospectively followed up with 3 patients who had antenatally diagnosed CCAM and nonimmune hydrops fetalis with predicted mortality. All patients declined or were not candidates for fetal intervention and were treated with standard prenatal betamethasone to increase lung maturity. Results: Three fetuses had CCAM and nonimmune hydrops fetalis diagnosed prenatally. After a course of prenatal steroids during the second trimester, all 3 patients had resolution of their hydrops and were delivered at term without respiratory distress. Conclusions: Nonimmune hydrops fetalis in fetuses with congenital cystic adenomatoid malformation is a harbinger for fetal demise. The resolution of hydrops in these patients after receiving steroid therapy is an interesting and compelling observation. Because the mechanism of this process is speculative, further studies are needed to elucidate the relationship between antenatal steroids and maturation of congenital cystic adenomatoid malformation. J Pediatr Surg 38:508-510.     

Clinical aspects of intestinal neuronal dysplasia

Purpose: The aim of this study was to determine the presence of specific clinical symptoms in intestinal neuronal dysplasia (IND) and whether it correlates to the severity of histopathologic findings. Methods: A group of 44 severe IND and a group of 16 mild IND patients diagnosed by means of a histochemical rectal biopsy were compared with a group of 37 patients with functional constipation (FC) with normal rectal biopsy results. Results: Patients with severe IND began their symptoms at an earlier age than those with mild IND and FC (5.2 [plusmn] 112 months v 17.5 [plusmn] 23 months and 22.5 [plusmn] 21.8 months, respectively; P [lt ] .001). The presence of intestinal obstruction symptoms was more frequent in severe IND patients than in mild IND and FC patients (45.5% v 18.8% v 2.7%, respectively; P [lt ] .001). The presence of a fecaloma and soiling were less frequent in the severe IND group than in mild IND and FC groups (20.5% v 56.3% v 59.5%, respectively; P [lt ] .001 and 15.9% v 31.3% v 59.5%, respectively; P [lt ] .001). Barium enema results showed a lower incidence of rectosigmoid distension in severe IND if compared with mild IND and FC groups (45.5% v 57.1% v 96.9%; P [lt ] .001). Internal sphincter relaxation was absent frequently in the severe IND group compared with the FC group (47% v 26.9%, respectively; P [lt ] .05). Conclusions: Intestinal neuronal dysplasia is a distinct histopathologic and clinical entity. Its clinical, radiologic, and manometric presentation correlates to the severity of histochemical findings.     

Cystic anomalies of biliary tree in the fetus: is it possible to make a more specific prenatal diagnosis?

Background/Purpose: Biliary tree cystic malformations (BCM) occur rarely. Current progress in ultrasonography makes it possible to identify them prenatally. The aim of this study was to analyze retrospectively prenatal ultrasound patterns of 5 consecutive subhepatic cysts in an effort to differentiate the BCM before birth and onset of symptoms. Methods: The prenatal ultrasound patterns of 5 consecutive BCM were correlated with the postnatal diagnosis. Results: Case 1 showed a hyperechogenic cyst that underwent enlargement during fetal life; the diagnosis at birth was an obstructed choledochal cyst (CC). In cases 2 and 3, an anechoic cyst with small, stable dimensions during pregnancy was identified; a biliary atresia (BA) type III-C was confirmed at birth. A slightly hyperechogenic cyst with no increase in size at repeated prenatal scans, was observed in cases 4 and 5; a CC and a cystic lesion at the confluence of the hepatic ducts (without obstruction) were diagnosed postnatally, respectively. Conclusions: The ultrasound scan pattern and size allow to make a prenatal differential diagnosis of BCM. Anechoic, small cyst in the hepatic hilum is highly suspicious for BA. Large, echoic or enlarging cyst is strongly suggestive of [ldquo ]obstructed[rdquo ] CC. Echoic, small and stable cyst is more suggestive of [ldquo ]unobstructed[rdquo ] CC. J Pediatr Surg 37:1191-1194.     

Development of intrahepatic biliary stones after excision of choledochal cysts

Background: The incidence of intrahepatic cholelithiasis and cholangitis has not yet been well studied postoperatively in patients with choledochal cysts. Methods: One hundred three patients with choledochal cysts had operative cholangiography, underwent standard excision of a choledochal cyst with Roux-en-Y hepatico-jejunal anastomosis, and were at a mean follow-up of 12[frac12] years. The incidence of intrahepatic bile duct stones was analyzed according to the 3 morphologic types of intrahepatic bile duct observed at initial operative cholangiography: type 1, no dilatation of the intrahepatic bile ducts; type 2, dilatation of the intrahepatic bile ducts but without any downstream stenosis; and type 3, dilatation of the intrahepatic bile ducts associated with downstream stenosis. Initially, there was no evidence of intrahepatic bile duct stones in any of the 103 patients. Results: Among 50 type 1 patients, intrahepatic cholelithiasis developed in only 1 patient (2%). Among 43 type 2 patients, 1 patient (2%) had intrahepatic cholelithiasis, and 2 (5%) had postoperative cholangitis. Among 10 type 3 patients, 4 (40%) had intrahepatic cholelithiasis (P [lt ] .01), and 3 (30%) had postoperative cholangitis. Time intervals between the initial surgery and the first identification of intrahepatic stones ranged from 3 to 22 years. Conclusions: One of the major causes of formation of intrahepatic cholelithiasis has been clarified; patients with intrahepatic biliary dilatation with downstream stenosis can get intrahepatic bile duct stones long after excision of a choledochal cyst.