Congenital diaphragmatic hernia: prenatal evaluation with MR lung volumetry--preliminary experience.

PURPOSE: To determine the interobserver variability of prenatal magnetic resonance (MR) lung volumetry and to assess the value of MR lung volumetric findings as predictors of outcome in fetuses with congenital diaphragmatic hernia. MATERIALS AND METHODS: Prenatal MR imaging was performed in 26 fetuses with unilateral congenital diaphragmatic hernia. Two independent observers performed planimetric measurement of lung volume. Relative lung volume was calculated as the observed total lung volume expressed as a percentage of the total lung volume predicted from fetal size. Relative lung volume was correlated with the ultrasonographic lung-head ratio in left-sided congenital diaphragmatic hernias evaluated before 27 weeks gestation (n = 21) and with pregnancy outcome in all cases of isolated left-sided congenital diaphragmatic hernia without prenatal intervention (n = 11). RESULTS: Observers demonstrated excellent agreement in total lung volume measurements at MR imaging, with an intraclass correlation coefficient of 0.95. Relative lung volume was positively correlated with lung-head ratio (r = 0.78, P <.001). By using rank order analysis in the pregnancy outcome group, relative lung volume was predictive of prognosis (P <.05) when adjusted for gestational age at delivery and birth weight. Three of four fetuses with a relative lung volume of less than 40% died. CONCLUSION: Interobserver agreement is high at MR lung volumetry, and its findings are predictive of outcome in fetuses with isolated left-sided congenital diaphragmatic hernia.

Safety of chronic fetal vascular access in the sheep model.

OBJECTIVE: Long-term access to the fetal circulation has the potential to open up new perspectives in the treatment of numerous fetal anomalies. The purpose of this study was to investigate the safety of long-term catheterization of fetal placental vessels. METHODS: A midline laparotomy was performed in 4 time-mated pregnant ewes at 125 days' gestation (term 145 days). Placental vessels were exposed by a small uterine incision. A specially designed catheter was inserted into a placental vessel over a length of 3 cm, the distal end of the catheter was tunneled underneath the maternal skin and attached to a subcutaneous port implanted in the maternal flank. All pregnancies were allowed to go to term. RESULTS: Ewes and fetuses tolerated the placement of the catheter and port without complications. The catheter remained patent in all cases. All lambs were delivered vaginally at term and did not require resuscitation after birth. No fetal anomalies or growth restriction were noted. CONCLUSION: The ovine placental vessel can be accessed long term without complication.

Normal and hypoplastic fetal lungs: volumetric assessment with prenatal single-shot rapid acquisition with relaxation enhancement MR imaging.

PURPOSE: To determine which parameters are most closely correlated with normal fetal total lung volume and to investigate the use of these parameters in the evaluation of fetal pulmonary hypoplasia. MATERIALS AND METHODS: Single-shot rapid acquisition with relaxation enhancement (RARE) magnetic resonance (MR) imaging was used to perform planimetric measurement of total lung volume in 46 fetuses at 18-32 weeks gestation. Total lung volume was correlated with gestational age, and biometric parameters in fetuses were correlated with normal chest findings at ultrasonography (US) (n = 24). This analysis was used to evaluate relative lung volume in fetuses suspected of having pulmonary hypoplasia (n = 22). RESULTS: Normal fetal total lung volume was strongly correlated with liver volume measured at MR imaging (r = 0.94), fetal weight estimated at US (r = 0.93), head circumference measured at US (r = 0.90), and gestational age (r = 0.87). In fetuses suspected of having pulmonary hypoplasia, the relative lung volume varied from 4.6% to 81.6% when the observed total lung volume was expressed as a percentage of the predicted total lung volume. CONCLUSION: Normal fetal total lung volume is strongly correlated with biometric measurements. Relative fetal lung volume can be calculated by expressing the observed volume as a percentage of the predicted volume calculated from biometric measurements; knowledge of the relative fetal lung volume assists in the confirmation and quantification of fetal pulmonary hypoplasia.

Cord ultrasonic transection procedure for selective termination of a monochorionic twin.

Placental vascular communications can present a life-threatening problem in monochorionic twins when one fetus has a lethal anomaly. Although selective feticide is the best option for salvaging the normal twin, techniques normally employed (i.e. intracardiac potassium, air embolism) are not prudent given the common circulatory system. Furthermore, in monoamniotic, monochorionic twin gestations it is important to transect the umbilical cord completely to prevent entanglement of the dead fetus around the cord of the normal twin. We present two cases of monochorionic twins in which the cords were transected with a harmonic scalpel under ultrasonic guidance via one trocar. The harmonic scalpel is an instrument which can simultaneously coagulate and cut blood vessels or tissues. The cord ultrasonic transection procedure is a novel, minimally invasive technique which offers several advantages over the methods currently used for selective feticide in discordant monochorionic twin gestations.

Slide tracheoplasty for congenital tracheal stenosis: a case report.

BACKGROUND/PURPOSE: A variety of techniques have been used to manage pediatric congenital tracheal stenosis. The authors report the technique of slide tracheoplasty for a child with long congenital tracheal stenosis. METHODS: A 2-year-old male presented with a history of stridor with feeding. Bronchoscopy findings showed 50% stenosis from complete cartilaginous rings, extending from 2.5 cm below the vocal cords to 2 cm above the carina. Through a neck incision, the trachea was exposed from the cricoid to both bronchi and transected at the midpoint of the stenosis. The upper trachea was split anteriorly to the area of stenosis just below the cricoid. The lower trachea was split posteriorly in the midline. Posterior dissection allowed sliding and anastomosis of both tracheal segments while the lateral vascular supply was left intact. A brace was placed to maintain cervical flexion, and the patient underwent extubation in the operating room. RESULTS: He recovered without complication and was dis charged on postoperative day 4. CONCLUSION: Slide tracheoplasty offers several advantages for tracheal reconstruction because it is performed with the native tracheal tissues, can be accomplished through a transverse collar incision, and can repair long stenoses without significant tracheal shortening.

Sonographic prognostic factors in fetuses with sacrococcygeal teratoma.

BACKGROUND: A subset of fetuses with sacrococcygeal teratoma (SCT) develops hydrops caused by high-output heart failure. Identification of fetuses at risk for hydrops is important because fetal intervention may reverse the pathophysiology of the disease. To date, no reliable sonographic prognostic factors have been identified. METHODS: An experienced sonologist reviewed the sonographic records of 17 fetuses with SCT referred to the authors' institution. Size of the tumor was measured and corrected for fetal size. The appearance of the tumor (solid versus cystic) and its vascularity were graded on a subjective scale of 1 to 5. RESULTS: Only 4 of 12 fetuses that had hydrops survived; of the survivors, 3 had undergone fetal intervention. All nonhydropic fetuses survived. Fetuses with hydrops had tumors that were mainly solid and highly vascular, whereas nonhydropic fetuses had predominantly cystic tumors with comparatively less vascularity. There was no significant difference in tumor size between these 2 groups. CONCLUSIONS: Fetuses with SCT that are mainly solid in appearance and are highly vascularized have a higher risk of getting hydrops in utero. Tumor size is not an independent prognostic factor.

Fetal pulmonary sequestration: a favorable congenital lung lesion.

OBJECTIVE: We reviewed the perinatal clinical course of prenatally diagnosed pulmonary sequestrations to determine the natural history of this anomaly. METHODS: From January 1992 to August 1998, 192 women were referred to the University of California, San Francisco, Fetal Treatment Center because obstetric ultrasound had demonstrated fetal lung lesions. In 14 fetuses, the echogenic lung masses were pulmonary sequestrations deriving arterial blood supply from clearly identifiable systemic arteries rather than the pulmonary artery. We examined records of the 14 fetuses and documented the location of the lesion, gestational age at diagnosis, need for fetal intervention, prenatal and postnatal complications, gestational age at delivery, and survival. RESULTS: There were 16 intrathoracic pulmonary sequestrations in 14 fetuses (eight left-sided, four right-sided, two bilateral). Three fetuses had histologically mixed lesions (congenital cystic adenomatoid malformation and pulmonary sequestration). The mean age at diagnosis was 23 weeks' gestation (range 19-31 weeks). Two fetuses required prenatal intervention (placement of a thoracoamniotic shunt for drainage of an ipsilateral tension hydrothorax). The mean gestational age at delivery was 37 weeks (range 32-40 weeks). The large lesions of four fetuses regressed completely prior to birth, and the lesions of the remaining ten fetuses were electively resected after birth without causing morbidity or mortality. CONCLUSION: Pulmonary sequestrations are a subgroup of congenital lung lesions with a favorable outlook; many regress prenatally, and the persistent ones are resected safely postnatally. Pulmonary sequestrations cause hydrops only because of a tension hydrothorax, which can be drained prenatally, if necessary.

One-stage correction of high imperforate anus in the male neonate.

PURPOSE: The aim of this study was to examine the feasibility, safety, and short-term outcome of complete one-stage repair of high imperforate anus in the newborn boy. METHODS: A retrospective review was conducted of five full-term male infants who underwent posterior sagittal anorectoplasty without a colostomy within the first 48 hours of birth. Preoperative imaging was performed to assess associated anomalies. All infants underwent cystoscopy before the perineal operation to determine the level of the urinary tract fistula, if present. After completion of the anoplasty, all were turned supine and the colon irrigated free of meconium. Follow-up ranged from 10 to 24 months. RESULTS: Laparotomy was not required for any patient. Three patients had a rectoprostatic urethral fistula, one a rectovesical fistula, and one no fistula (common wall at level of prostate). Tapering rectoplasty was required for only the one patient with a rectovesical fistula. There were no intraoperative complications. All patients passed stool within 12 hours after operation and took full feeding by 48 hours. The average hospital stay was 7 days. Postoperative and stenosis occurred in one patient secondary to parental noncompliance with the postoperative dilation regimen. There were no perineal wound complications. All patients have a strong urinary stream and defecate spontaneously without the aid of oral medication or rectal stimulation or enemas. CONCLUSIONS: One-stage repair of high imperforate anus in the male neonate is feasible without short-term genitourinary or gastrointestinal morbidity. Whether it is preferable compared with a delayed (two or three stage) repair depends on ultimate long-term anorectal function, which cannot be assessed for several years.

Natural history of fetuses with cleft lip.

The prospect of fetal surgery for cleft lip is predicated on our ability to accurately identify fetuses with clefts and exclude those that have associated anomalies. Prenatal ultrasound is currently the most appropriate means with which to do this. We reviewed the ultrasonographic data from two large perinatal referral institutions to determine the natural history of fetuses with cleft lip who may be candidates for fetal surgery. Forty fetuses had a cleft lip diagnosed prenatally by ultrasound. In this group, severe associated anomalies were common (30 of the 40) and multiple (23 of the 40) in a majority of fetuses. Life-threatening anomalies, such as central nervous system and cardiac anomalies, were the most common defects. As a result, many fetuses were aborted therapeutically or died in the perinatal period. Out of 12 surviving fetuses, only six had isolated clefts, and two surviving fetuses, diagnosed with isolated cleft lip, had no defect identified postnatally. This information has important implications for the perinatal management of fetuses with cleft lip and the potential role of fetal intervention.

Are bilateral fetal lung masses double trouble?

OBJECTIVES: To examine the perinatal natural history of bilateral fetal cystic lung masses. METHODS: The records of a tertiary medical center over a 3-year period were reviewed for cases of fetal bilateral pulmonary masses. RESULTS: Three of 98 fetuses referred for evaluation over a 3-year period from September of 1995 to August of 1998 had bilateral lung lesions. Two of these cases resulted in live births, while one, associated with hydrops, resulted in death after preterm delivery. CONCLUSIONS: Similar to prenatally diagnosed unilateral lung lesions, hydropic fetuses with bilateral cystic lung lesions have a poor prognosis. Nonhydropic fetuses, however, may be asymptomatic despite persistent lesions on postnatal CT scan. These observation may prove helpful for prenatal counseling for these rare lesions.

Treating the snakebitten child in North America: a study of pit viper bites.

BACKGROUND/PURPOSE: Snakebite envenomation is a potentially life-threatening form of trauma, the dangers of which are amplified in children because their smaller size increases the relative dose of venom received. The authors reviewed a large series of snakebitten children to address the medical and fiscal issues of treating these patients. METHODS: The records of 37 snakebitten children (1987 through 1997) were analyzed for demographic data, signs of envenomation, use of specific therapies (antivenin, blood products, or surgery), length of hospitalization, complications, and cost of care. RESULTS: Fifty-four percent of the children had a major envenomation demonstrated by systemic symptomatology, laboratory analysis, or need for surgery. All children made full recoveries with most receiving only supportive care (92%). The average time to emergency department presentation was 8 hours, where all children with major envenomations and those requiring specific therapies (surgery, clotting factors) were identified. Cost analysis showed an average of $2,450 dollars per child with the majority of expenses attributable to length of hospitalization. CONCLUSIONS: Most snakebitten children completely recover with minimal supportive care, and they can be cared for safely and cost effectively as outpatients if no signs of major envenomation are noted within 8 hours of the bite.