Reduced-size lung transplantation in neonatal swine: technique and short-term physiological response

Lung transplantation is now a clinical reality in adults but is limited by the scarcity of appropriate donors. The donor shortage is even more acute for neonatal and pediatric patients. Reduced-size lung grafts would expand the pool of appropriate cadaveric donors and allow HLA-matched living related lobar or segmental lung transplants. To evaluate this experimentally, we developed a model of pulmonary lobar transplantation in neonatal pigs and studied the acute hemodynamic response after transplanting the left lower lobe from a more mature donor to a neonatal recipient. Technical considerations included using the recipient atrial appendage for the pulmonary venous anastomosis. Nine pairs of pigs underwent left lateral thoracotomy. The recipient left atrial and pulmonary arterial pressures, cardiac output, and pulmonary vascular resistance were measured before pneumonectomy and after left lower lobe transplantation. Although the left atrial and pulmonary arterial pressures remained unchanged after transplantation, there was a 15% increase in pulmonary vascular resistance and a 23% reduction in cardiac output. Neither change was statistically significant. The distribution of blood flow through the left and right pulmonary arteries was unchanged after transplantation. We conclude that lobar transplantation is technically feasible in immature animals and that the pulmonary venous anastomosis to the left atrial appendage facilitates the procedure. This model may prove useful in studying lung transplantation in immature recipients and expedite implementation of reduced-size lung transplantation in neonatal and pediatric patients.

Cervical cystic hygroma in the fetus: clinical spectrum and outcome

Cervical cystic hygroma is thought by most pediatric surgeons to be an isolated, usually resectable lesion with an excellent prognosis. However, prenatal sonography has revealed a high "hidden mortality" among fetuses with this condition, and most perinatologists consider it to be uniformly fatal. In an attempt to resolve these two differing perspectives, we analyzed 29 cases seen at two centers over 4 years. Of 27 fetuses diagnosed before 30 weeks' gestation, only one survived. Twenty-five of the 27 were aborted; severe hydrops was present in 21 of these 25. Two of the 27, both with stigmata of Noonan's syndrome, underwent spontaneous regression during the second trimester: one died at 2 weeks of age, and the other survived. Successful karyotypes were obtained on 17 fetuses: nine were normal, seven were 45X, and one was trisomy 21. Fetuses with abnormal karyotypes had a lower incidence of polyhydramnios (0% v 67%), additional anomalies (12% v 67%), and consanguinity or a history of abnormal pregnancies (0% v 89%). Two fetuses were diagnosed after 30 weeks' gestation. Neither had hydrops, polyhydramnios, associated anomalies, or an abnormal karyotype. One had a completely normal sonogram at 17 weeks' gestation. Both were operated on within the first 4 days of life; one did well without complications, and the other required a permanent tracheostomy because of extensive hypopharyngeal involvement. A cystic hygroma presenting in the fetus has a different natural history and prognosis from one presenting postnatally. The vast majority of fetal cases are diagnosed before 30 weeks' gestation, and present with hydrops or diffuse lymphangiomatosis. The dismal outlook in this group justifies elective termination in most cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Studies in fetal wound healing, VI. Second and early third trimester fetal wounds demonstrate rapid collagen deposition without scar formation

The mechanisms that underlie the lack of scarring in fetal wounds are unknown, but probably relate to the control of collagen fibrillogenesis. The role of collagen in the fetal wound matrix is controversial, and several wound implant models have been used to evaluate collagen deposition in fetal wounds. Unfortunately, these models create an artificial wound environment and may thereby affect the results. In order to study fetal wound collagen deposition in linear wounds without artificially altering the wound environment, we applied a highly sensitive immunohistochemical technique that uses antibodies to collagen types I, III, IV, and VI. We found that collagen was deposited in fetal wounds much more rapidly than in adult wounds. Wound collagen deposition occurred in a normal dermal and mesenchymal pattern in second and early third trimester fetal lambs. These findings are consistent with the observation that the fetus heals rapidly and without scar formation. In contrast, wounds in late gestation fetal lambs showed some evidence of scar formation. Further studies may suggest ways to alter the adult wound so that it heals in a fetal manner.

Pulmonary lobar transplantation in neonatal swine: a model for treatment of congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) babies born with severe pulmonary hypoplasia are unsalvageable despite maximal therapy including extracorporeal membrane oxygenation (ECMO). Lung transplantation is a potential treatment for these otherwise doomed infants using ECMO as a bridge to transplantation. Cadaveric, or living related donation of a more mature reduced size lung (pulmonary lobe or segment) may help solve the critical donor shortage problem. We evaluated the physiological response of mature left lower lobe (LLL) transplants in neonatal swine with the hemodynamic conditions of CDH simulated by occlusion of the right pulmonary artery (PA), and also studied the pulmonary function of the mature lobar graft compared with the neonatal lung. LLL transplantation was well tolerated and resulted in minimal alteration in hemodynamic parameters. The response to right PA occlusion was similar pre- and posttransplantation with a fall in cardiac output and a significant rise in pulmonary vascular resistance. Compared with the contralateral native lung, the lobar graft was preferentially ventilated with resultant higher pH (7.65 +/- 0.17 v 7.41 +/- 0.08, P less than .01) and lower pCO2 (17 +/- 6 v 36 +/- 5, P less than .001). The more mature lobar graft was preferentially ventilated due to the increased compliance compared with the neonatal right lung (8.16 +/- 1.28 v 5.48 +/- 0.82 mL/cm, P less than .0001). Reduced size lung transplantation is technically feasible and may help solve the donor problem for severe CDH neonates for whom no effective therapy is currently available.

Studies in fetal wound healing. IV. Hyaluronic acid-stimulating activity distinguishes fetal wound fluid from adult wound fluid

Recent clinical and experimental evidence suggests that the fetus responds to injury in a fashion fundamentally different from that of the adult. Our initial experience with human open fetal surgery reinforces experimental observations that the fetal wounds heal without the scarring, inflammation, and contraction that often accompany adult wounds. In this study we examine fetal wound fluid in an attempt to elucidate the control mechanisms that endow the fetus with unique healing properties. The extracellular matrix of fetal wounds is rich in hyaluronic acid, a glycosaminoglycan found in high concentrations whenever there is tissue proliferation, regeneration, and repair. We establish that wound fluid from the fetus contains high levels of hyaluronic acid-stimulating activity that may underlie the elevated deposition of hyaluronic acid in the fetal wound matrix. In contrast there was no hyaluronic acid-stimulating activity present in adult wound fluid. Hyaluronic acid, in turn, fosters an extracellular environment permissive for cell motility and proliferation that may account for the unique properties observed in fetal wound healing.

Gastrointestinal tract obstruction in the fetus

Surgical advice is often sought when a prenatal diagnosis of gastrointestinal tract obstruction is made. We reviewed our experience with 17 such cases during a 4-year period. Eight fetuses had complete proximal obstruction. Seven of the 8 did well after maternal transport to a perinatal center and prompt neonatal surgery. Six fetuses had distal obstruction with dilated bowel and increased peristalsis. Two died after birth (1 with severe associated anomalies and 1 with short-bowel syndrome), and the other 4 did well. Three fetuses had a false-positive diagnosis of in utero meconium peritonitis. Two died and the other had no postnatal evidence of obstruction. Our data suggest (1) polyhydramnios may not be present early in gestation or with distal obstruction; (2) other anomalies, including a family history of cystic fibrosis, should be sought; (3) dilated bowel with increased peristalsis is diagnostic of fetal gastrointestinal tract obstruction, whereas intra-abdominal calcification and ascites are nonspecific findings; (4) late development of ascites in a fetus with documented obstruction may be an indication for early delivery; and (5) prenatal diagnosis permits appropriate counseling, planned delivery, and prompt postnatal resuscitation and surgery with a good prognosis in most cases.

Esophageal adenocarcinoma 20 years after esophageal atresia repair

We report a case of esophageal adenocarcinoma 20 years after esophageal atresia repair. From one case report it is premature to recommend cancer surveillance for all esophageal atresia patients. However, the first survivors are now reaching an age when esophageal cancer related to chronic esophagitis may become more prevalent.

Cesarean delivery and hysterotomy using an absorbable stapling device

The absorbable stapling device was used in 22 hysterotomies in gravid rhesus monkeys. The efficacy of the device, subsequent fertility and delivery route, fetal effects, and pathohistology were all studied. No statistically significant difference between experimental and control animals was noted.

Fetal diaphragmatic hernia: ultrasound diagnosis and clinical outcome in 38 cases

A previously published survey has evaluated the natural history and clinical outcome of fetal diaphragmatic hernia (CDH) in 94 cases. This study showed that the prenatal diagnosis is accurate, the mortality is high (80%), and polyhydramnios is a prenatal predictor of poor clinical outcome. As a follow-up study, 38 consecutive cases of CDH diagnosed in utero were evaluated and treated by the same surgical team. This permitted detailed assessment of prognostic factors and evaluation of the impact of extracorporeal membrane oxygenation (ECMO) on outcome. We found the following. (1) Survival is poor despite optimal postnatal therapy including ECMO. (2) Polyhydramnios is both a common prenatal marker for CDH (present in 69% of fetuses) and a predictor for poor clinical outcome (only 18% survival), but tends to occur after the second trimester. (3) Amniocentesis is indicated to rule out chromosomal abnormalities that were present in 16% of fetuses. (4) All 14 fetuses diagnosed prior to 25 weeks' gestation died. Improved postnatal therapy or surgical intervention before birth will be necessary to salvage the CDH fetus with an early gestational diagnosis or associated polyhydramnios.

Surgical treatment of pancreas divisum causing pancreatitis in children

Although controversial, pancreas divisum has been implicated as a cause of acute pancreatitis when there is stenosis of the accessory papilla that drains the duct of Santorini. Over the past 5 years, four children with pancreas divisum and recurrent pancreatitis were successfully treated surgically. The diagnosis was made by endoscopic retrograde cholangiopancreatography (ERCP) in each case. Surgical treatment included sphincteroplasty to the accessory papilla to improve drainage of the duct of Santorini, opening the ampulla of Vater to expose the ostium of the duct of Wirsung to enlarge it, and cholecystectomy.

Fetal cystic adenomatoid malformation of the lung: apparent improvement in utero

Fetal cystic adenomatoid malformation is a rare pulmonary abnormality, usually involving only a part of the lung, that is characterized by excessive growth of the terminal respiratory elements. The natural history of this lesion and hence the prognosis after antenatal detection is still unclear. We report two cases of large cystic adenomatoid malformation, diagnosed prenatally, in which the size of the mass diminished visibly during the third trimester. Both fetuses had excellent outcomes after surgery. These findings suggest that when a cystic adenomatoid malformation is diagnosed antenatally, the initial impression concerning the size of the mass and final prognosis may not necessarily predict outcome, because there may be improvement during fetal life.

Gastric infarction secondary to small bowel obstruction: a preventable complication after Nissen fundoplication

Two infants who required a Nissen fundoplication for severe gastroesophageal reflux developed small bowel obstruction 5 and 21 months postoperatively. Their inability to belch or vomit, coupled with inappropriate airway management during resuscitation led to massive gastric dilation, and eventual infarction of their stomach, duodenum, and small intestines. These complications are preventable with appropriate management.

Transamniotic fetal feeding. II. A model of intrauterine growth retardation using the relationship of "natural runting" to uterine position

Intrauterine growth retardation (IUGR) is a leading cause of perinatal morbidity and mortality. Most IUGR is the result of inadequate transfer of nutrients from mother to fetus. Transamniotic fetal feeding (TAFF) has been proposed as a method of treating IUGR in which nutrients, infused into the amniotic fluid, would be swallowed, absorbed, and utilized by the growth retarded fetus. To study this hypothesis, we have developed a rabbit model for IUGR and TAFF. We studied the effects of maternal nutritional deprivation, uterine artery ligation, and fetal position in the uterine horn on fetal body and organ growth in 96 rabbit litters. Nutritional deprivation (n = 28) and vascular interruption (n = 34) yielded inconsistent results with high fetal mortality. We were surprised to find that fetal growth was directly and consistently related to position in the uterine horn. There is a highly significant difference (P less than .0001) in weight between siblings in the no. 1 and no. 3 positions in the rabbit uterine horn at 30 days gestation that is not present at 23 days. This "natural" runting resembles human IUGR, which occurs during the last trimester of pregnancy and shows relative brain sparing. This model, in combination with our previously reported technique for TAFF, will make possible a controlled study of the efficacy of TAFF in the treatment of IUGR.

Erythropoietin production by the fetal liver in an adult environment

To gain insight into the mammalian liver to kidney erythropoietin (Ep) switch, we heterotopically transplanted livers from preswitch, switched, and postswitch fetal and newborn lambs into normal adult sheep. Recipients' serum Ep and circulating reticulocyte levels were serially determined until rejection of the graft and compared with identical samples from sham-operated control adult ewes. Transplantation of preswitch and switched fetal livers caused an impressive rise in recipients' serum Ep activity and provoked a corresponding increase in reticulocytosis. In contrast, Ep activity and reticulocyte counts did not change from preoperative levels in adult ewes transplanted with postswitch livers or in the sham-operated controls. The production of Ep by the preswitch fetal liver in the adult environment was not dependent on the presence or absence of host kidneys and was stimulated by anemic hypoxia. These results suggest that the fetal liver is capable of producing relatively large amounts of Ep activity, and the production of Ep can be maintained in the adult environment in the presence of functional adult kidneys. This argues against suppression of liver Ep production by renal Ep, or some other factor in the postnatal environment, and suggests that the liver to kidney switch of Ep production during ontogeny may represent a genetically determined event.

Auxiliary transplantation of the fetal liver. II. Functional evaluation of an intraabdominal model

To evaluate the use of the fetal liver as an auxiliary graft, we have developed a model of intraabdominal heterotopic transplantation of late gestational fetal lamb livers into weanling lambs. Thirty-eight transplants have been performed of which 31 were technically successful. Twenty-three grafts functioned for intervals of 5 to 22 days after transplantation. Grafts were functionally evaluated by analysis of total bile acid and bilirubin excretion. To determine whether host liver excretory function would influence function of the graft, common bile duct ligated recipients were compared with recipients with normal host liver function. We found that (1) intraabdominal auxiliary transplantation of the fetal lamb liver is technically feasible; (2) the fetal liver graft is capable of rapid adaptation and can assume a significant portion of host excretory function; and (3) excretory function of the fetal liver is proportional to the functional demands of the host. Auxiliary transplantation of the fetal liver is a promising alternative to current methods of liver transplantation.

Fetal diaphragmatic hernia: ultrasound diagnosis and clinical outcome in 19 cases

Nineteen cases of congenital diaphragmatic hernia diagnosed in utero are reported with emphasis on sonographic findings, associated congenital and karyotypic abnormalities, the presence or absence of polyhydramnios, and clinical outcome. The survival of these infants was very poor despite accurate prenatal diagnosis, maximal surgical and medical treatment and maximal postnatal care. The overall survival rate was 10.5%, and for fetuses who lived beyond delivery the survival rate was 20%.

The effects of intrauterine pneumonectomy in lambs. A morphometric study of the remaining lung at term

A morphometric study was made of the remaining lung of term lambs that had undergone left pneumonectomy at 60, 80, 100, or 120 days gestation. All pneumonectomy lambs showed some compensatory growth since right lung volume to body weight ratio was higher in all lambs after pneumonectomy than in term controls. In 3 lambs operated at 80, 100, and 120 days, respectively, however, compensatory volume increase was more complete than in the other lamb of each age pair or the 2 lambs operated at 60 days. Despite individual variation, the potential for compensatory lung growth seems greater in the canalicular and later stages than in the pseudoglandular. Measurements indicating distal air-space size (volume density of alveoli, volume density of alveolar duct, surface density of alveolar epithelium, numerical density of alveoli, and mean linear intercept) were similar in all animals, but total alveolar surface area and number increased proportionally to lung volume. The fact that the remaining lung compensates by increasing alveolar number rather than by enlarging air spaces is a model of human developmental abnormalities in which the alveolar number at birth is greater than normal (polyalveolar). At the intraacinar level, a higher than normal proportion of muscularized arteries was found in lambs operated early in gestation and in lambs with smaller compensatory lung growth: an inverse relationship was seen--the lower the lung volume the higher the proportion of muscular arteries. The cause for this is unknown, but may result from the relatively increased flow to a vascular bed smaller than that of two normal lungs.

Congenital diaphragmatic hernia: current controversies in prenatal and postnatal management

A prenatal diagnosis of congenital diaphragmatic hernia (CDH) is associated with a poor prognosis, especially if diagnosed early in gestation and associated with polyhydramnios. Although uncommon, it is important to rule out associated anomalies, so that elective termination can be considered. If CDH is an isolated anomaly, the outcome is related to the degree of pulmonary hypoplasia caused by viscera displacing the lung in utero. Unfortunately, our ability to assess lung size, and thus prognosis, is limited. Most babies with CDH either die shortly after birth or survive to lead normal lives, so that continuation of the pregnancy is extremely unlikely to produce a chronically ill pulmonary cripple. The fetus should be followed with periodic ultrasounds and delivered at a perinatal center with appropriate neonatal and surgical expertise. There is no evidence that altering the timing or mode of delivery affects outcome. The only way to alter outcome and save the severely affected fetus is to remove the viscera from the chest and allow the fetal lung to develop before birth. Despite the fact that fetal repair of CDH makes sense physiologically, however, it remains a highly experimental technique. Postnatal management of CDH involves resuscitation, paralysis, and positive pressure ventilation. The practice of emergency repair is not supported by pathophysiology, and operation should be delayed until the patient has been stabilized. Mortality is often due to pulmonary hypoplasia, but in some cases, there is a period of deterioration due to pulmonary hypertension resulting in right-to-left shunting (persistent fetal circulation). Pharmacological agents are often used to decrease pulmonary vascular resistance and increase cardiac output.(ABSTRACT TRUNCATED AT 250 WORDS)

Perinatal management of the fetus with an abdominal wall defect

The antenatal diagnosis of abdominal wall defects has allowed improved perinatal management. For fetuses with associated anomalies, the options of elective termination or minimal intervention can be offered. Our ability to predict the extent of bowel damage in gastroschisis based on the ultrasound findings enables us to offer early delivery to those fetuses who are at high risk. The data are not clear at the present time whether cesarean section offers any advantage. These fetuses should, however, be delivered at a center which is capable of providing high level medical and surgical care to these potentially ill infants. Initial resuscitation of these neonates requires early insertion of an intravenous line and a nasogastric tube, the administration of antibiotics, sterile coverage of the eviscerated bowel, and careful attention to temperature instability. Neonates with gastroschisis should be operated on as soon as they are stable, whereas infants with omphalocele can be investigated for associated anomalies prior to surgery. Primary fascial closure is performed whenever possible. Where this is not possible, a staged repair using a silastic chimney achieves closure within 3-6 days. Skin coverage alone or nonoperative management is reserved for the few cases with giant omphalocele, associated anomalies, or poor operative risk. Decisions about primary versus delayed closure, while usually dictated by clinical judgement, can be aided by indirect measurement of intraabdominal pressure. Postoperative ventilation, and consideration of long-term nutritional needs, are also important parts of the perioperative management.

Ureteropelvic junction obstruction in the fetus

Ureteropelvic junction (UPJ) obstruction is being detected with increasing frequency before birth. To clarify the natural history of fetal UPJ obstruction, we reviewed our experience managing 28 fetuses; there were 16 bilateral cases for a total of 44 renal units. None required decompression before birth. We found that fetal bilateral UPJ obstruction is associated with significant morbidity and mortality; resolution of fetal hydronephrosis secondary to UPJ obstruction is rare; antenatal diagnosis of UPJ obstruction improves clinical management by allowing early detection and appropriate treatment of otherwise clinically undetectable disease; oligohydramnios in the mature fetus with bilateral UPJ obstruction is an indication for early delivery and immediate repair; and prenatally diagnosed UPJ obstructions should be repaired as early as possible after birth.

Transplantation of fetal hematopoietic stem cells in utero: the creation of hematopoietic chimeras

Transplantation of normal, immature, fetal hematopoietic cells into a preimmune fetal recipient with a congenital hemoglobinopathy may allow partial reconstitution of normal hemoglobin production without the complications associated with postnatal bone marrow transplantation (immunosuppression and the occurrence of graft versus host disease). In order to test this hypothesis the naturally occurring polymorphism at the beta-hemoglobin locus of the sheep was used as a marker for engraftment and hematopoietic chimerism. Intraperitoneal injection of allogeneic fetal stem cells into normal fetal lambs resulted in hematopoietic chimerism in three of four surviving recipients. This chimerism has been sustained for 6 months after birth and 9 months after engraftment, without evidence of graft versus host disease, and without the use of immunosuppressive therapy.

Fetal sacrococcygeal teratoma

Sacrococcygeal teratoma (SCT) is being diagnosed before birth with increasing frequency. We were recently consulted about management of a 22-week fetus with SCT and reviewed our experience (6 cases) and the literature. We found that most fetal SCT present from 22 to 34 weeks gestation with a uterus enlarged by the tumor and/or associated polyhydramnios; although the American Academy of Pediatrics Surgical Section clinical classification is an important prognostic indicator in neonatal SCT, it does not appear to predict outcome in fetal SCT; associated chromosomal abnormalities or life threatening anomalies are rare; presentation after 30-weeks gestation is a relatively good prognostic sign with fetal survival, after planned cesarean delivery, in 6 of 8 cases; and hydrops and/or placentomegaly in association with fetal SCT predicts fetal demise soon after diagnosis with 7 of 7 cases dying in utero.

Auxiliary transplantation of the fetal liver. I. Development of a sheep model

Current methods of orthotopic liver transplantation are expensive, entail high morbidity and mortality, and are limited by a serious shortage of donor organs for the pediatric recipient. Auxiliary transplantation of livers from anencephalics is a potential solution to the problems of size discrepancy and organ availability for the pediatric patient. To investigate the feasibility of auxiliary fetal liver transplantation, we have developed a sheep model of auxiliary transplantation of the fetal liver into the adult neck. We report here the results of the transplantation of 32 fetal lamb livers ranging in age from 100 to 140 days gestation (term 145 days). We conclude that (1) fetal organ harvest can be effectively accomplished by surface cooling followed by umbilical cold perfusion; (2) auxiliary transplantation of the fetal lamb liver is technically feasible; (3) the fetal liver can survive on umbilical inflow alone but function is improved by hepatic arterial inflow; and (4) the fetal liver is sensitive to excessive flow or pressure and is best transplanted in a parallel vascular arrangement. Auxiliary transplantation of the fetal liver is a promising alternative to current methods of liver transplantation.

Fetal surgery in the primate. III. Maternal outcome after fetal surgery

Maternal safety and future reproduction potential are paramount considerations in fetal surgery. In a series of 102 fetal surgical procedures on time-dated pregnant monkeys, we examined the maternal complications, the potential for future pregnancy, and the effects of uterine staples used for hysterotomy and uterine closure. There were significant maternal complications associated with the development of the present techniques for fetal surgery including 3 maternal deaths, 5 uterine ruptures, and 5 cases of wound infection of dehiscence. All were preventable with knowledge gained from this experience. Compared with a control unoperated breeding colony, fetal surgery did not interfere with subsequent reproductive capacity in animals that had uterine closure with absorbable sutures. However, metal staple hysterotomy resulted in a markedly decreased fertility rate probably related to exposure of the endometrial cavity to a permanent foreign body. Although serious maternal complications occurred in this series, many are avoidable as we improve both our obstetric management and our anesthetic and surgical techniques. Prenatal intervention carries considerable maternal risk and should not be attempted clinically under any but the most rigorous conditions.

Transamniotic fetal feeding. III. The effect of nutrient infusion on fetal growth retardation

The small-for-gestational age (SGA) infant resulting from intrauterine growth retardation (IUGR) is at high risk for perinatal complications and chronic morbidity. Most IUGR is the result of inadequate transfer of nutrients and/or oxygen from mother to fetus. Transamniotic fetal feeding (TAFF) has been proposed as a method of treating IUGR in which nutrients infused into the amniotic fluid would be swallowed, absorbed, and used by the growth retarded fetus. To study the efficacy of TAFF in the treatment of IUGR, we have previously described a rabbit model for TAFF that takes advantage of the relationship between "natural runting" (IUGR) and position on the uterine horn. We report on a controlled study of the effects of specific nutrient infusion on fetal growth retardation in this model. The infusion of dextrose, a dextrose-amino acid mixture, or lipid did not reverse or ameliorate fetal IUGR compared with controls. In addition, the infusion of lipid emulsion resulted in chronic lipid aspiration and further growth retardation. This work does not support the use of TAFF as a prenatal treatment for IUGR and suggests that oxygen may be the growth-limiting factor in most substrate deficiency IUGR. In addition, the infusion of solutions containing lipid may be harmful to the developing fetus.

Tapering duodenoplasty for megaduodenum associated with duodenal atresia

Six neonates with duodenal atresia and megaduodenum were treated with tapering duodenoplasty in addition to duodenoduodenostomy. This technique is simple and helps restore effective peristalsis in the proximal duodenal pouch.

Temporary cutaneous umbilical vesicostomy in premature infants with urethral obstruction

The umbilicus has proven to be an excellent site for temporary cutaneous vesicostomy. It is easy to construct, functions well without complications of stomal prolapse or stenosis, and is easily closed with excellent cosmetic results.

Development of a fetal renal function test using endogenous creatinine clearance

Selecting appropriate management for the fetus with obstructive uropathy depends on our ability to accurately assess the severity of existing renal damage and to predict the potential for recovery of renal function if the obstruction is relieved. Diagnosis and treatment would be markedly enhanced by a simple, safe, quantitative fetal renal function test. To answer the question of whether endogenous fetal creatinine clearance (CrC) is an accurate measure of glomerular filtration rate (GFR) in the obstructed fetal kidney, we compared fetal CrC to a standard test for GFR--iothalamate clearance (IC). Six fetal lambs underwent unilateral ureteral ligation at 60 to 63 days gestation (term = 145 days). The contralateral unobstructed kidneys served as a control. At a second operation at 113 to 120 days, renal function was measured by hourly split urine collections for determination of CrC, IC, and fractional sodium excretion on each side over a 4-hr study period. There was excellent correlation of CrC with IC in all kidneys (r = 0.997, P less than 0.001, y = 1.14 x). Compared to the control side, the obstructed fetal kidneys had significantly decreased GFR and abnormal tubular function with marked sodium loss.(ABSTRACT TRUNCATED AT 250 WORDS)

Urinary extravasation in the fetus with obstructive uropathy

Urinary extravasation resulting in either urinary ascites or an isolated perirenal urinoma is relatively common in the fetus with severe obstructive uropathy. We examined the effect of fetal urinary extravasation on the developing kidney and abdominal wall in 12 fetuses taken from a series of 44 cases of fetal urinary tract obstruction. Based on this experience, we conclude that fetal urinary extravasation has predictable pathophysiologic consequences. Fetal urinary ascites appears to ameliorate obstruction-induced renal dysplasia by decompressing the high-pressure, obstructed fetal urinary system. Conversely, contained urinomas secondary to ureteropelvic junction obstruction provide inadequate decompression and are associated with renal dysplasia. Last, the severity of abdominal wall laxity (prune belly) relates directly to the timing and degree of fetal ascites.

Correction of congenital diaphragmatic hernia in utero. IV. An early gestational fetal lamb model for pulmonary vascular morphometric analysis

Infants born with congenital diaphragmatic hernia (CDH) often have specific pathologic abnormalities of the pulmonary microcirculation that result in high pulmonary vascular resistance and extrapulmonary right-to-left shunting after birth. In an attempt to make an animal model with similar vascular changes, we created CDH in fetal lambs at 60 to 63 days gestation, repaired some at 100 to 113 days gestation, and subsequently performed morphometric analysis of the pulmonary vasculature. Creation of CDH at this early gestational age resulted in a high fetal mortality rate. In the unrepaired CDH lambs, the pulmonary vascular abnormalities were more severe in the left lung. Similar to human CDH, diaphragmatic hernia in the fetal lamb resulted in a decrease in the total size of the pulmonary vascular bed, a decrease in the number of vessels per unit area lung, and increased muscularization of the arterial tree. Fetal surgical repair of CDH restored the pulmonary arterial bed towards normal.

Fetal cystic adenomatoid malformation: prenatal diagnosis and natural history

We studied the natural history and pathophysiology of congenital cystic adenomatoid malformation (CCAM) detected prenatally by ultrasound in twelve fetuses. Two types of fetal CCAM can be distinguished by gross anatomy, ultrasound findings, and prognosis. Microcystic lesions are usually associated with fetal hydrops and have a poor prognosis (five cases with one survivor). Antenatal diagnosis, maternal transport, and immediate thoracotomy after birth allowed the first reported survival of a newborn with a large microcystic CCAM. Macrocystic lesions are not usually associated with hydrops and have a favorable prognosis (five of seven survived). We conclude that fetuses with hydrops are at high risk for fetal or neonatal demise without intervention. Fetuses with CCAM but without hydrops have a good chance for survival with maternal transport, planned delivery, and immediate neonatal resuscitation and surgery.

Recent advances in prenatal diagnosis and treatment

This article is a summary of the prenatal and perinatal management of a variety of congenital lesions as practiced by the fetal treatment program at the University of California in San Francisco. Emphasis is placed on those lesions that are amenable to fetal intervention.

Experimental studies on prenatal treatment of congenital anomalies

Development of fetal animal models for congenital anomalies helps elucidate the pathophysiological consequences of the disease process as well as the efficiency of prenatal intervention in ameliorating the disease. The experimental work that supports the pathophysiological rationale for in-utero correction of diaphragmatic hernia and urinary tract obstruction is reviewed in this article.

Diaphragmatic hernia in the fetus: prenatal diagnosis and outcome in 94 cases

Most babies born with congenital diaphragmatic hernia (CDH) die after birth. The natural course of CDH in the human fetus is not known. We found 94 cases of fetal CDH in the records of surgeons and obstetricians surveyed in the United States and Canada. We found the following: (1) prenatal diagnosis of CDH is accurate and current techniques can detect lethal nonpulmonary anomalies and prevent diagnostic errors; (2) despite optimal conventional therapy, most fetuses with detectable CDH will die in the neonatal period (80% mortality); (3) polyhydramnios is both a common prenatal marker for CDH (present in 76% of fetuses) and a predictor for poor clinical outcome (only 11% survived); (4) fetal CDH is a dynamic process--nonsurvivors have larger defects and may have more viscera displaced into the chest at an earlier stage of development. Surgical intervention before birth may be necessary to improve survival of the fetus with CDH and polyhydramnios.

Major childhood tumor resection using normovolemic hemodilution anesthesia and hetastarch

Acute normovolemic hemodilution is a safe technique for minimizing operative blood loss during major tumor resection in children. Based on our experience using hemodilution anesthesia in 14 successful extensive tumor resections, we conclude the following: (1) this is an effective means of reducing use of bank blood and thus avoiding the risks of multiple transfusions; (2) it facilitates surgical dissection due to increased visibility with dilute blood, and decreased bleeding due to controlled hypotension; (3) this technique is acceptable for Jehovah's Witnesses; (4) hetastarch is an effective, inexpensive colloid hemodiluent which minimized perioperative edema compared to crystalloid hemodilution.

Comparison of fetal, newborn, and adult wound healing by histologic, enzyme-histochemical, and hydroxyproline determinations

We compared simultaneous healing processes in fetal, newborn, and maternal rabbits using a miniaturized wound cylinder of expanded Gore-Tex tubing. The tubing was placed subcutaneously in fetal and maternal rabbits on day 23 of pregnancy (term = 31 to 32 days), and in 7-day-old newborn rabbits. At specific intervals, the tubing was removed and analyzed for hydroxyproline accumulation, histology, and cellular enzyme-histochemistry. Granulation tissue ingrowth and accumulation of hydroxyproline were each inversely related to age (fetus greater than newborn greater than maternal). The fetus showed an impressive infiltration of macrophages by day 4, fibroblasts by day 7, and a conspicuous lack of neutrophils in all specimens. Newborns and mothers had few cells until day 7, when a mixture of macrophages, neutrophils, and some fibroblasts appeared. We conclude that the fetus heals wounds rapidly by both mesenchymal cell proliferation and collagen deposition, and that these processes are more rapid in fetuses than in newborn or adult animals despite relative fetal hypoxemia.

The missing link in the pathogenesis of gastroschisis

Is gastroschisis embryologically distinct from omphalocele or simply a ruptured small omphalocele (hernia of the umbilical cord)? Serial sonographic imaging of a fetus with a small omphalocele at 27 weeks gestation has now provided the "missing link" in the pathogenesis of gastroschisis by documenting in utero rupture resulting in a gastroschisis.

Management of the fetus with congenital hydronephrosis II: Prognostic criteria and selection for treatment

Selecting appropriate management for the fetus with bilateral congenital hydronephrosis depends on our ability to accurately assess the severity of existing renal damage and to predict the potential for recovery of renal and pulmonary function if the obstruction is relieved. We reviewed our experience with 20 fetuses with congenital bilateral hydronephrosis to determine the prognostic value of various criteria used to assess functional potential, including temporary catheter exteriorization to measure fetal urine output and composition. Based on autopsy, biopsy, or clinical outcome, ten fetuses were classified retrospectively as "poor function," and ten fetuses as "good function." The good function group could be distinguished from the poor function group by the following criteria: Amniotic fluid (AF) status at presentation (P less than .001), ultrasound appearance of the fetal kidneys (P less than .05), fetal urine sodium and chloride concentration and osmolarity (P less than .001), and hourly urine output (P less than .02), but not by fetal urine iothalamate excretion or potassium and creatinine concentrations (P greater than .05). Based on these results, we have identified prognostic criteria that accurately identify the fetus with "good function" from the fetus with "poor function." We also reviewed the clinical management of our last 12 unreported cases. Ten fetuses had undergone diagnostic catheter placement and in utero renal function testing. This led to placement of a therapeutic indwelling catheter-shunt in seven fetuses (three required multiple shunts) and a suprapubic vesicostomy in another. Catheter related complications, including three cases of chorioamnionitis, emphasize the need for better methods of in utero decompression in selected cases. Our ability to select appropriate management has improved markedly.

Management of toxic epidermal necrolysis in a pediatric burn center

Toxic epidermal necrolysis (TEN) is an acute severe exfoliative skin and mucosal membrane disorder with a clinical picture similar to a total-body scald injury. Toxic epidermal necrolysis shares features with severe erythema multiforme seen in Stevens-Johnson syndrome, and is thought by some to be a maximal expression of this syndrome. Drug-related TEN is uncommon in children. Mortalities of 70% have been reported, and death is usually secondary to the bacterial and metabolic consequences of a large open wound. Over the past two years, four children with probable drug-induced TEN were treated successfully. Since the problems of infection, wound care, fluid balance, nutrition, and pain control are similar in TEN and major burn patients, treatment using the principles of burn care may improve survival.

Correction of congenital hydrocephalus in utero II: Efficacy of in utero shunting

To study the effect of in utero ventricular decompression of hydrocephalus on brain development and prognosis, and to evaluate the function and possible complications of different shunt designs, we created fetal hydrocephalus in 28 fetal lambs and 17 fetal monkeys by injecting kaolin into the cisterna magna during the third trimester. One fetal lamb had indwelling intracranial subdural and amniotic cavity pressure catheters placed to study serial changes in the relationship of intracranial pressure (ICP) and amniotic fluid pressure (AFP) from the time of injection until term. Twenty hydrocephalic fetal lambs underwent ventricular decompression--ventriculoamniotic (V-A), N = 10; ventriculo-right atrial (V-RA), N = 9; and ventriculo-pleural (V-PL), N = 1--21 to 25 days after the kaolin was injected; seven hydrocephalic fetuses were left unshunted as controls (CON). Eight fetal monkeys underwent V-A decompression 14 to 21 days after kaolin injection; nine were left unshunted as controls. All animals were delivered by cesarean section near term, assessed for viability and their brains examined grossly and microscopically. After kaolin injection in the fetal lamb, ICP (r = 0.94) and ICP minus AFP (r = 0.93) rose in a linear fashion, while AFP showed no trend (r = 0.22). All unshunted newborn lambs and monkeys had split sutures, dilated ventricles, and thinned cortical mantle. Most shunted lambs showed anatomic improvement with decreased head circumference, overriding sutures, normal-sized ventricles, and improved survival. However, histopathology revealed marked white matter destruction. In contrast, most shunted monkeys showed little anatomic improvement. Both shunted and unshunted monkey brains showed a severe inflammatory ventriculitis. In both lambs and monkeys, shunting was associated with a variety of complications including subdural hematoma, subdural hygroma, shunt infection, shunt occlusion, and improper shunt tip placement. In this experimental model, in utero decompression of obstructive hydrocephalus improves overall survival, improves gross ventriculomegaly, does not improve histopathologic brain damage, and is associated with significant complications. The choice of the optimal shunt design and the effect on postnatal neurologic function requires further study. This work emphasizes the need for continuing research in an animal model prior to human application.

Correction of congenital hydronephrosis in utero IV: in utero decompression prevents renal dysplasia

Renal dysplasia (RD) is commonly seen in babies with urinary tract obstruction (UTO). Recent experimental evidence suggests that early fetal UTO leads to the development of RD. The RD seen in children with congenital UTO is usually not reversible, even when the obstruction is relieved soon after birth. Is the RD associated with congenital UTO preventable or reversible by decompression of the urinary tract early in gestation? If so, at what stage of development must this decompression be performed? We produced complete unilateral ureteral obstruction in 25 early second trimester (62 to 65 days) lamb fetuses, a procedure that results in ipsilateral RD at term (140 days). At a second operation, 20, 40, or 60 days after the initial procedure, we decompressed the obstructed kidney by a cutaneous end-ureterostomy. The contralateral unobstructed kidneys served as controls. Renal function (urine output and iothalamate clearance) and histopathology were evaluated after delivery at term. Recovery of renal function was directly proportional to the duration of in utero decompression and inversely proportional to duration of obstruction. In addition, in utero decompression prevented or greatly ameliorated the development of RD. However, some postobstructive changes persisted; these were proportional to the length of in utero obstruction. These results substantiate the clinical impression that some human fetuses with congenital UTO may benefit from early in utero decompression.

Colon interposition: an adjuvant operation for short-gut syndrome

Six infants with short-gut syndrome refractory to medical management underwent isoperistaltic colon interposition (length 11.7 +/- 3.1 cm.). The abdominal catastrophes that required extensive intestinal resection were: volvulus (3), necrotizing enterocolitis (2), and gastroschisis with intestinal atresia (1). No infant had another major congenital anomaly. The average trial of attempted medical therapy prior to colon interposition was 5.5 +/- 3.6 months. There was no perioperative mortality or morbidity associated with the colon interposition. Following the colon interposition, three infants were weaned from total parenteral nutrition (TPN) in 3 +/- 1 months and all survived. In contrast, three infants could not be withdrawn from TPN and they died secondary to complications of TPN (2 from sepsis and 1 from hepatic failure). Long-term survival was associated with a greater length of small bowel remaining after the initial resection (51 +/- 12 cm v 35 +/- 24 cm), colon interposition at a younger age (3 +/- 1 months v 8 +/- 3.5 months), and a shorter duration of medical management prior to colon interposition (2.8 +/- 0.8 months v 6.7 +/- 5.0 months). All survivors are now tolerating a regular diet and having one to four formed stools per day. Normal somatic growth and developmental milestones are being achieved. The follow-up period is from 24 to 84 months. Our experience with the colon interposition in the patient with short gut syndrome has led us to conclude that when a reasonable trial of medical management has failed, a colon interposition is a safe and effective adjuvant to treatment.

Experimental pulmonary hypoplasia and oligohydramnios: relative contributions of lung fluid and fetal breathing movements

Inhibition of fetal breathing movements or increased loss of fetal lung fluid into the amniotic space have been suggested as two possible mechanisms causing pulmonary hypoplasia in the setting of oligohydramnios (OH). We examined the effect of OH produced by amniotic fluid shunting (AS) into the maternal abdominal cavity, ablation of fetal breathing by high cervical cord transection (CT), and CT and AS combined on fetal rabbit lungs at 24 days gestation. Lung growth at term (31 days) was measured by lung DNA content and wet lung weight. Compared to unoperated controls, newborns undergoing either AS alone or CT alone had much smaller lungs. When compared to CT alone, CT with AS resulted in a further significant decrease in lung growth. Thus, even when fetal breathing was eliminated by CT, AS caused further hypoplasia. If pulmonary hypoplasia in OH is related to increased loss of lung fluid, then tracheal ligation (TL) should prevent this process. TL combined with AS produced lungs with the same DNA content as controls, and thus the hypoplastic effects of OH were reversed by TL. Although fetal breathing is clearly important for lung growth, it appears that inhibition of fetal breathing is not the predominant etiology of oligohydramnios-related pulmonary hypoplasia. Fetal intrapulmonary fluid is formed by active transport across pulmonary epithelium, and may serve to distend potential airways and stimulate growth. These experiments suggest that lung hypoplasia associated with OH is related to loss of this internal stenting force.

Cryotherapy of subglottic hemangioma

The natural history of the hemangioma is spontaneous regression; therefore, most lesions require no treatment. The large occlusive subglottic hemangioma which presents before the age of 6 months, however, may be life-threatening. Two infants with subglottic hemangiomas with complete upper airway obstruction were treated successfully with cryotherapy, after tracheostomy. In each case the cryoprobe was placed transbronchoscopically on the subglottic hemangioma at -80 degrees C. for 30 to 45 seconds, the freezing interval varying with the age of the patient. One infant is asymptomatic and has had the tracheostomy tube removed. The other infant, after successful cryosurgical treatment, died from an unrelated illness. The histopathology of the larynx 3 1/2 months after cryotherapy of the hemangioma showed tracheal reepithelialization, active regeneration of cartilage with maintenance of luminal diameter, minimal submucosal fibrosis, and minimal residual hemangioma. Cryotherapy for subglottic hemangiomas offers many advantages including hemostasis, controlled local surgical injury, subsequent rapid healing of tissues with minimal fibrosis, and preservation of lumen without stricture. Previous forms of therapy which have been supplanted include radiotherapy, injection of sclerosing substances, systemic steroids, and surgical excision. Carbon dioxide laser is an effective therapeutic modality that we reserve for selected smaller hemangiomatis lesions of the subglottic area.