Faculty Bibliography

PURPOSE: Available data comparing the management and outcome of right-sided (R-CDH) vs left-sided congenital diaphragmatic hernia (L-CDH) are inconsistent. Large-volume CDH studies are limited by small numbers of R-CDH or are confounded by compilations from multiple institutions with multiple treatment strategies. Consequently, they are underpowered to draw conclusions. To define the behavior and outcomes of R-CDH better, we report the largest single-institution series of R-CDH and ask if factors traditionally linked to poor prognosis in L-CDH were applicable to R-CDH. METHODS: We reviewed a single institution's experience with 267 consecutive evaluable neonates with unilateral CDH repaired from 1990 to 2006, with specific focus on R-CDH. chi(2) tests were performed for disease-related categorical variables. Two-tailed unpaired t tests were used for continuous variables. Factors associated with morbidity and survival were determined by univariate regression. Statistical significance was set at P < .05. RESULTS: Forty right-sided (15%) and 227 (85%) left-sided cases of CDH were identified. Prenatal diagnosis was made in 20 right-sided vs 170 left-sided defects (50% vs 75%, P < .01). Survival was 22 of 40 in R-CDH compared with 175 of 227 in L-CDH (55% vs 77%, P < .01). Extracorporeal membrane oxygenation was required in 16 right-sided and 33 left-sided cases (40% vs 15%, P < .001). A diaphragmatic patch was used in 22 of 29 right-sided compared with 82 of 199 left-sided repairs (76% vs 41%, P < .01); rates of abdominal wall prosthesis were also higher in right-sided hernias (38% vs 19%, P < .05). No differences were detected in right-sided vs left-sided recurrences (14% vs 8%, P = .38), mean time from birth to operation (5.3 vs 4.8 days, P = .80), or presence of cardiac anomalies (15% vs 12%, P = .63). Morbidity persisting beyond 6 months of age was present in 16 of 22 R-CDH survivors compared with 76 of 175 L-CDH survivors (73% vs 43%, P > .05). Among R-CDHs, prenatal diagnosis was the only factor to predict survival by univariate regression (P < .01). Use of a prosthesis in the diaphragm (P < .05) for R-CDH repair correlated with morbidity. CONCLUSION: Although previous reports suggest that associated anomalies, need for extracorporeal membrane oxygenation, and time to repair can influence L-CDH survival, these data do not support extrapolation to R-CDH survival. Right-sided CDH carries a disproportionately high morbidity and mortality. Prenatal diagnosis was the only factor predictive of R-CDH survival. Morbidity may correlate with use of prosthetic material for R-CDH repair. Right-sided CDH is a unique disease that may require a modified antenatal consultation.

Right-sided diaphragmatic defects represent less than 20% of all congenital diaphragmatic hernias (CDH). Recent data suggest that right CDH (R-CDH) may carry a disproportionately high morbidity as well as increased rates of extracorporeal support when compared with left CDH. Treatment of infants with R-CDH may be further complicated by anatomical distortion unique to right-sided defects. We report 2 cases of azygous vein cannulation in neonates with large isolated R-CDH. Both infants had postnatal deteriorations within 48 hours, met our criteria for extracorporeal membrane oxygenation (ECMO), and underwent venoarterial cannulations through the right neck. In each case, the venous cannula passed directly into the azygous vein and failed to provide adequate ECMO support. Echocardiography confirmed both cases of azygous cannulation. In one child, the right atrium was successfully cannulated after 90 minutes of extensive cannula manipulation. This child survived a 5-day ECMO course and is alive at 22-month follow-up. In the second child, despite prolonged efforts at cannula repositioning, cannulation of the right atrium was not achieved. We did not offer central cannulation because of a rapidly deteriorating clinical course, with expiration in several hours. At autopsy, a dilated azygous vein was evident as a result of inferior vena cava compression by a malpositioned liver. The possibility of azygous vein cannulation may be increased in neonates with R-CDH and has not been previously reported. When evaluating infants with R-CDH for ECMO, clinicians must recognize the possibility of azygous cannulation and its potentially lethal consequences, and should anticipate alternative venous cannulation

Therapeutic thoracentesis may be preferable over tube thoracostomy in select clinical scenarios in which a symptomatic pleural effusion develops after an isolated and limited physiologic insult. Notable risks in patients undergoing bedside thoracentesis include parenchymal lung injury, abdominal organ injury, and incomplete pleural drainage. These risks are driven in part by inexperienced house officers performing the technique, coupled with technical limitations imparted by hospital-provided thoracentesis kits. To address these concerns, we present a modification to the technique of bedside thoracentesis whereby a triple-lumen catheter is placed into the pleural space over a guidewire. This approach overcomes shortcomings of the packaged thoracentesis kits, improves patient comfort, minimizes the risk of lung injury, and provides more complete drainage of the pleural cavity in patients requiring therapeutic thoracentesis. This approach carries a small risk of air entry into the pleural space, which can be minimized with meticulous technique. Furthermore, by using a Seldinger approach, our technique can improve resident comfort with thoracentesis by drawing on a more robust skill set that likely already has developed during their training in central line placement.

Children requiring surgical intervention for pancreatic disease may be at risk long term for exocrine insufficiency and glucose intolerance. Pediatric surgeons must balance the need to perform adequate surgical resection while preserving as much normal pancreatic parenchyma as possible. Neoplasms of the middle pancreatic segment with low malignant potential and isolated trauma to the pancreatic body or neck represent 2 conditions where extensive pancreatic resection is unnecessary. Central pancreatectomy for such lesions is well described in adults. Reconstruction of the distal pancreatic remnant is traditionally performed via Roux-en-Y pancreaticojejunostomy. Pancreaticogastrostomy is an alternative approach that has been used to reconstruct the distal pancreas in the adults. Pancreaticogastrostomy offers several technical advantages over pancreaticojejunostomy. Because children may be uniquely susceptible to the long-term consequences of excessive pancreatic resection, 2 cases using this technique of central pancreatectomy with pancreaticogastrostomy are described

BACKGROUND: Congenital diaphragmatic hernia (CDH) is a birth defect with significant morbidity and mortality. Knowledge of diaphragm morphogenesis and the aberrations leading to CDH is limited. Although classical embryologists described the diaphragm as arising from the septum transversum, pleuroperitoneal folds (PPF), esophageal mesentery and body wall, animal studies suggest that the PPF is the major, if not sole, contributor to the muscular diaphragm. Recently, a posterior defect in the PPF has been identified when the teratogen nitrofen is used to induce CDH in fetal rodents. We describe use of a cell-based computer modeling system (Nudge++) to study diaphragm morphogenesis. METHODS AND RESULTS: Key diaphragmatic structures were digitized from transverse serial sections of paraffin-embedded mouse embryos at embryonic days 11.5 and 13. Structure boundaries and simulated cells were combined in the Nudge++ software. Model cells were assigned putative behavioral programs, and these programs were progressively modified to produce a diaphragm consistent with the observed anatomy in rodents. Homology between our model and recent anatomical observations occurred under the following simulation conditions: (1) cell mitoses are restricted to the edge of growing tissue; (2) cells near the chest wall remain mitotically active; (3) mitotically active non-edge cells migrate toward the chest wall; and (4) movement direction depends on clonal differentiation between anterior and posterior PPF cells. CONCLUSION: With the PPF as the sole source of mitotic cells, an early defect in the PPF evolves into a posteromedial diaphragm defect, similar to that of the rodent nitrofen CDH model. A posterolateral defect, as occurs in human CDH, would be more readily recreated by invoking other cellular contributions. Our results suggest that recent reports of PPF-dominated diaphragm morphogenesis in the rodent may not be strictly applicable to man. The ability to recreate a CDH defect using a combination of experimental data and testable hypotheses gives impetus to simulation modeling as an adjunct to experimental analysis of diaphragm morphogenesis.

The authors report the case of a grade 4 liver laceration caused by blunt abdominal trauma. The liver injury was managed nonoperatively, both initially and after an episode of delayed hemorrhage. The patient suffered 2 additional as yet unreported complications of pediatric liver injury: a right pleural effusion causing respiratory embarrassment followed by duodenal obstruction; the latter was caused by hypertrophy of the left lobe of the liver. Although numerous reports suggest that delayed hemorrhage after pediatric liver injury should be managed operatively, the mortality of such intervention remains high, reaffirming the dictum that one must treat the patient and not the injury.

We present the case of a 24-year-old man with recurrent peptic ulcers and hypergastrinemia, in whom a multidisciplinary investigation for gastrinoma revealed a duodenal web. The affected duodenal segment was excised, and a gastroduodenostomy with highly selective vagotomy was performed. Postoperative serum gastrin levels returned to the normal range over the next 6 weeks. Congenital duodenal anomalies are unusual causes of gastric outlet obstruction in adults. Chronic gastric outlet obstruction secondary to an adult duodenal web can induce neurohumoral changes in gastric function, which enhance both acid output and gastrin secretion. This case reminds clinicians to consider congenital anomalies in adults presenting with recurrent peptic ulcers and hypergastrinemia.

INTRODUCTION: The persistent morbidity and mortality of congenital diaphragmatic hernia are largely due to associated pulmonary hypoplasia. We have shown previously that three antioxidants (vitamin C, glutathione, and vitamin E) could accelerate the growth of fetal hypoplastic lungs grown in culture. We hypothesize that this occurs via a reductant mechanism. METHODS: Timed-pregnant rats were gavage-fed nitrofen (100 mg) on day 9.5 of gestation (term = day 22). Fetal lungs were harvested on day 13.5 and placed in organ culture containing serum-free BGJb medium with antibiotics. After randomization, the lung organ cultures were divided into a control group (n = 31) and an experimental group that received the antioxidant N-acetylcysteine (NAC, 100 microM, n = 31). The fetal lung organ cultures were grown for 4 days at 37 degrees C with 5% CO(2). Computer-assisted digital tracings of the airways were performed daily on live, unstained specimens, and lung bud count, perimeter, and area were measured. After 4 days, lungs were pooled, homogenized, and assayed for reduced and oxidized glutathione, normalized to protein, as an estimate of the tissue redox potential. Data were expressed as means +/- SEM, and statistical comparisons were performed using Student's unpaired t test, with P < 0.05 considered significant. RESULTS: Area, perimeter, lung bud count, and complexity (as measured by the perimeter/square root of area) were all significantly increased with NAC treatment from day 2 onward. Reduced glutathione levels were significantly increased following NAC administration (67.1 +/- 5.8 versus 37.5 +/- 4.2 micromol/mg, P = 0.0004). The ratio of reduced to oxidized glutathione was 2.23. CONCLUSIONS: N-Acetylcysteine stimulates nitrofen-induced hypoplastic fetal lung growth in organ culture and increases the ratio of reduced to oxidized glutathione. These data support the concept that oxidation-reduction (redox) may be an important control mechanism for fetal lung growth.