Impact of Focused Abdominal Ultrasound Utilization on Outcomes for Children With Midgut Volvulus.

BACKGROUND: Ultrasound (US) is gaining acceptance for the evaluation of midgut volvulus in children. However, its impact on clinical outcomes is unknown. We aim to determine whether using US as a first-line modality changes imaging mobilization, time to surgery and re-feeding, length of stay, and frequency of bowel necrosis, short bowel syndrome, and death. METHODS: An IRB-approved retrospective cohort study was performed at a tertiary pediatric institution. Eighty children with surgically confirmed midgut volvulus from 2014 to 2021 were compared before and after implementation of US as first-line imaging and based on the modality used to diagnose midgut volvulus. RESULTS: Outcomes were not statistically different pre- versus post-implementation. Compared with patients who had UGI only, those who had US only or both had significantly quicker imaging mobilization (median: -33 min; 95% CI: -61.2, -4.8; p = 0.023 and median: -31 min; 95% CI: -58.5, -3.6; p = 0.028 respectively). Patients with US only were less likely to have bowel necrosis compared with those who had UGI only (9.1% versus 43.8%, p = 0.042). Patients who had US only or both were less likely to develop short bowel syndrome compared to UGI only (4.8% US only, 0% both, 40% UGI only; p = 0.027 for US only, p = 0.005 for both). CONCLUSIONS: No statistically significant change in outcomes was found after implementation of US as first-line imaging for midgut volvulus. However, patients diagnosed with US only or US in combination with UGI had quicker imaging mobilization and decreased frequency of bowel necrosis and short bowel syndrome. Findings suggest that US has potential to improve patient outcomes. LEVEL OF EVIDENCE: III.

Case report: Spindle cell neoplasm presenting as a spontaneous intestinal perforation in a term infant.

Spontaneous intestinal perforations in the neonatal population are mostly associated with low birth weight, prematurity, and necrotizing enterocolitis. Spontaneous intestinal perforation in the absence of these risk factors is extremely rare and should raise clinical concern for an underlying bowel pathology. Here we present a unique case of a normal-weight, full-term girl with spontaneous intestinal perforation due to a spindle cell neoplasm with a novel BRAF mutation and infantile fibrosarcoma-like morphology. Though rare, malignancy should be considered in the differential diagnosis for bowel perforation in an otherwise healthy, term infant as complete surgical excision can be curative.

Spontaneous reversal of stenosis in tissue-engineered vascular grafts.

We developed a tissue-engineered vascular graft (TEVG) for use in children and present results of a U.S. Food and Drug Administration (FDA)-approved clinical trial evaluating this graft in patients with single-ventricle cardiac anomalies. The TEVG was used as a Fontan conduit to connect the inferior vena cava and pulmonary artery, but a high incidence of graft narrowing manifested within the first 6 months, which was treated successfully with angioplasty. To elucidate mechanisms underlying this early stenosis, we used a data-informed, computational model to perform in silico parametric studies of TEVG development. The simulations predicted early stenosis as observed in our clinical trial but suggested further that such narrowing could reverse spontaneously through an inflammation-driven, mechano-mediated mechanism. We tested this unexpected, model-generated hypothesis by implanting TEVGs in an ovine inferior vena cava interposition graft model, which confirmed the prediction that TEVG stenosis resolved spontaneously and was typically well tolerated. These findings have important implications for our translational research because they suggest that angioplasty may be safely avoided in patients with asymptomatic early stenosis, although there will remain a need for appropriate medical monitoring. The simulations further predicted that the degree of reversible narrowing can be mitigated by altering the scaffold design to attenuate early inflammation and increase mechano-sensing by the synthetic cells, thus suggesting a new paradigm for optimizing next-generation TEVGs. We submit that there is considerable translational advantage to combined computational-experimental studies when designing cutting-edge technologies and their clinical management.

Degradation and in vivo evaluation of polycaprolactone, poly(ε-caprolactone-co-L-lactide), and poly-L-lactic acid as scaffold sealant polymers for murine tissue-engineered vascular grafts.

Aim: This study evaluates scaffold degradation and neotissue formation as a function of sealant polymer composition in tissue-engineered vascular grafts (TEVGs). Materials & methods: Scaffolds fabricated from polyglycolic acid core and sealant composed of polycaprolactone (PCL), poly-L-lactic-acid (PLLA) or 50:50 copolymer poly(ε-caprolactone-co-L-lactide) (PCLA) were analyzed in vitro using accelerated degradation and scanning electron microscopy, and in vivo following implantation in a murine inferior vena cava interposition model. Results:In vitro and in vivo characterization revealed statistically greater degradation of PCLA compared with both PCL and PLLA scaffolds, with similar neotissue formation across all groups. The wall thickness of PLLA TEVGs was statistically greater than PCL TEVGs at 2 weeks postimplant. Conclusion: Results of this study can be used to inform the rational design of future TEVGs.

The relationships of surgeon volume and specialty with outcomes following pediatric thyroidectomy.

BACKGROUND: Previous studies of pediatric thyroidectomies suggest a volume-outcome relationship, but none have focused exclusively on pediatric surgical specialists. Our objective was to examine the effects of pediatric surgeon volume and specialty on post-thyroidectomy outcomes. METHODS: The Pediatric Health Information System was queried for patients ≤21 years who underwent partial or total thyroidectomy between 2005 and 2016. Multivariable logistic regression with propensity score weighting was used to assess the relationships between surgeon volume or specialty and 90-day thyroidectomy-specific complications. High-volume surgeons/hospitals were defined as those in the top tertile of annual thyroidectomies. RESULTS: The inclusion criteria were met by 3149 patients. Patients treated by higher-volume surgeons had significantly fewer complications than those treated by lower-volume surgeons (15.0% vs. 19.2%, p = 0.01). Patients with thyroid cancer also had less morbidity when treated by higher-volume surgeons compared to lower-volume surgeons (25.0% vs. 35.1%, p = 0.03), as did children with Graves' disease (19.8% vs. 29.3%, p = 0.007). Patients managed by pediatric surgeons had fewer complications than those managed by pediatric otolaryngologists across all patients (14.0% vs. 22.5%, p < 0.001) and among cancer (25.3% vs. 42.1%, p < 0.001) and Graves' patients (20.1% vs. 37.3%, p < 0.001) specifically. CONCLUSIONS: Morbidity following pediatric thyroidectomy is associated with surgeon volume. TYPE OF STUDY: Prognostic Study. LEVEL OF EVIDENCE: Level II.

Complications after proctocolectomy and ileal pouch-anal anastomosis in pediatric patients: A systematic review.

BACKGROUND/PURPOSE: Colectomy with ileal pouch-anal anastomosis (IPAA) is the standard of care for patients with familial adenomatous polyposis (FAP) and refractory ulcerative colitis (UC). The rates of postoperative complications are not well established in children. The objective of this systematic review is to establish benchmark data for morbidity after pediatric IPAA. METHODS: PubMed, Embase, and The Cochrane Library were searched for studies of colectomy with IPAA in patients ≤21 years old. UC studies were limited to the anti-tumor necrosis factor-α agents era (1998-present). All postoperative complications were extracted. RESULTS: Thirteen studies met the inclusion criteria (763 patients). Compared to patients with FAP, UC patients had a higher prevalence of pouch loss (10.6% vs. 1.5%). Other major complications such as anastomotic leak, abscess, and fistula were uncommon (mean prevalence 4.9%, 4.2%, and 5.0%, respectively, for patients with UC; 8.7%, 4.2%, and 4.3% for FAP). The most frequent complication was pouchitis (36.4% of UC patients). CONCLUSIONS: Devastating complications from colectomy and IPAA are rare, but patients with UC have poorer outcomes than those with FAP. Much of the morbidity may therefore stem from patient or disease factors. Multicenter, prospective studies are needed to identify modifiable risks in patients with UC undergoing IPAA. LEVEL OF EVIDENCE: Prognostic, level II.

Designing a tissue-engineered tracheal scaffold for preclinical evaluation.

OBJECTIVE: Recent efforts to tissue engineer long-segment tracheal grafts have been complicated by stenosis and malacia. It has been proposed that both the mechanical characteristics and cell seeding capacity of TETG scaffolds are integral to graft performance. Our aim was to design a tracheal construct that approximates the biomechanical properties of native sheep trachea and optimizes seeding with bone marrow derived mononuclear cells prior to preclinical evaluation in an ovine model. METHODS: A solution of 8% polyethylene terephthalate (PET) and 3% polyurethane (PU) was prepared at a ratio of either 8:2 or 2:8 and electrospun onto a custom stainless steel mandrel designed to match the dimensional measurements of the juvenile sheep trachea. 3D-printed porous or solid polycarbonate C-shaped rings were embedded within the scaffolds during electrospinning. The scaffolds underwent compression testing in the anterior-posterior and lateral-medial axes and the biomechanical profiles compared to that of a juvenile ovine trachea. The most biomimetic constructs then underwent vacuum seeding with ovine bone marrow derived mononuclear cells. Fluorometric DNA assay was used to quantify scaffold seeding. RESULTS: Both porous and solid rings approximated the biomechanics of the native ovine trachea, but the porous rings were most biomimetic. The load-displacement curve of scaffolds fabricated from a ratio of 2:8 PET:PU most closely mimicked that of native trachea in the anterior-posterior and medial-lateral axes. Solid C-ringed scaffolds had a greater cell seeding efficiency when compared to porous ringed scaffolds (Solid: 19 × 104 vs. Porous: 9.6 × 104 cells/mm3, p = 0.0098). CONCLUSION: A long segment tracheal graft composed of 2:8 PET:PU with solid C-rings approximates the biomechanics of the native ovine trachea and demonstrates superior cell seeding capacity of the two prototypes tested. Further preclinical studies using this graft design in vivo would inform the rational design of an optimal TETG scaffold.

Endoscopic management of tissue-engineered tracheal graft stenosis in an ovine model.

OBJECTIVE: To evaluate the safety and efficacy of bronchoscopic interventions in the management of tissue-engineered tracheal graft (TETG) stenosis. STUDY DESIGN: Animal research study. METHODS: TETGs were constructed with seeded autologous bone marrow-derived mononuclear cells on a bioartificial graft. Eight sheep underwent tracheal resection and orthotopic implantation of this construct. Animals were monitored by bronchoscopy and fluoroscopy at 3 weeks, 6 weeks, 3 months, and 4 months. Bronchoscopic interventions, including dilation and stenting, were performed to manage graft stenosis. Postdilation measurements were obtained endoscopically and fluoroscopically. RESULTS: Seven dilations were performed in six animals. At the point of maximal stenosis, the lumen measured 44.6 ± 8.4 mm2 predilation and 50.7 ± 14.1 postdilation by bronchoscopy (P = 0.3517). By fluoroscopic imaging, the airway was 55.9 ± 12.9 mm2 predilation and 65.9 ± 22.4 mm2 postdilation (P = 0.1303). Stents were placed 17 times in six animals. Pre- and poststenting lumen sizes were 62.8 ± 38.8 mm2 and 80.1 ± 54.5 mm2 by bronchoscopy (P = 0.6169) and 77.1 ± 38.9 mm2 and 104 ± 60.7 mm2 by fluoroscopy (P = 0.0825). Mortality after intervention was 67% with dilation and 0% with stenting (P = 0.0004). The average days between bronchoscopy were 8 ± 2 for the dilation group and 26 ± 17 in the stenting group (P = 0.05). One hundred percent of dilations and 29% of stent placements required urgent follow-up bronchoscopy (P = 0.05). CONCLUSION: Dilation has limited efficacy for managing TETG stenosis, whereas stenting has a more lasting clinical effect. LEVEL OF EVIDENCE: NA. Laryngoscope, 127:2219-2224, 2017.

Intravascular Ultrasound Characterization of a Tissue-Engineered Vascular Graft in an Ovine Model.

Patients who undergo implantation of a tissue-engineered vascular graft (TEVG) for congenital cardiac anomalies are monitored with echocardiography, followed by magnetic resonance imaging or angiography when indicated. While these methods provide data regarding the lumen, minimal information regarding neotissue formation is obtained. Intravascular ultrasound (IVUS) has previously been used in a variety of conditions to evaluate the vessel wall. The purpose of this study was to evaluate the utility of IVUS for evaluation of TEVGs in our ovine model. Eight sheep underwent implantation of TEVGs either unseeded or seeded with bone marrow-derived mononuclear cells. Angiography, IVUS, and histology were directly compared. Endothelium, tunica media, and graft were identifiable on IVUS and histology at multiple time points. There was strong agreement between IVUS and angiography for evaluation of luminal diameter. IVUS offers a valuable tool to evaluate the changes within TEVGs, and clinical translation of this application is warranted.

Nonoperative management of esophageal perforations in the newborn.

BACKGROUND: Esophageal perforation in neonates occurs most often in cases of extreme prematurity and is commonly due to iatrogenic causes. Treatment over recent decades has become more conservative. The purpose of this study was to review cases of esophageal perforation in neonates and to describe the presentation, management, and outcomes. MATERIALS AND METHODS: A retrospective chart review was performed for patients with International Classification of Diseases, Ninth Revision code for esophageal perforation treated at our institution between the years 2009 and 2015. Data collected included demographic information, etiology of perforation (specifically focusing on cases secondary to orogastric tube placement), treatment course, time to resumption of enteral feeds, length of antibiotic use, time to subsequent radiographic resolution, and mortality. RESULTS: Twenty-five patients met study criteria. The average post-conceptual age at time of diagnosis was 26.5 ± 2.3 wk. All 25 patients were managed nonoperatively with bowel rest, parenteral nutrition, and broad-spectrum antibiotics. Enteral feeds were resumed after a median of 8 d (interquartile range [IQR]: 7-11), the median antibiotic duration was 7 d (IQR: 7-10), and the median time to follow-up esophagram was 7 d (IQR: 7-10). Overall, 24 of 25 patients (96%) demonstrated radiological resolution of perforation on initial follow-up esophagram. Four patients died during the study period, but no deaths were related to the diagnosis of esophageal perforation. CONCLUSIONS: In this largest reported sample of neonates treated for esophageal perforation, nonoperative management with bowel rest, parenteral nutrition, and antibiotics was successful.

A mouse model of endocardial fibroelastosis.

BACKGROUND: Endocardial fibroelastosis (EFE) is a pathologic condition of abnormal deposition of collagen and elastin within the endocardium of the heart. It is seen in conjunction with a variety of diseases including hypoplastic left heart syndrome and viral endocarditis. While an experimental model using heterotopic heart transplant in rats has been described, we sought to fully describe a mouse model that can be used to further elucidate the potential mechanisms of and treatments for EFE. MATERIALS AND METHODS: The hearts of 2-day-old C57BL/6 mice were transplanted into the abdomen of 7-week-old C57BL/6 mice. At 2 weeks, the hearts were harvested and histologic analysis was performed using hematoxylin and eosin, Masson's trichrome, Russell-Movat's pentachrome, Picrosirius red, Hart's, Verhoeff-Van Gieson, and Weigert's Resorcin-Fuchsin stains. Additionally, one heart was analyzed using transmission electron microscopy (TEM). RESULTS: Specimens demonstrated abnormal accumulation of both collagen and elastin within the endocardium with occasional expansion into the myocardium. Heterogeneity in extracellular matrix deposition was noted in the histologic specimens. In addition, TEM demonstrated the presence of excess collagen within the endocardium. CONCLUSIONS: The heterotopic transplantation of an immature heart into a mouse results in changes consistent with EFE. This model is appropriate to investigate the etiology and treatment of EFE.