Thoracostomy Tube Removal in Pediatric Trauma: Film or No Film?

BACKGROUND: Use of routine chest x-rays (CXR) following thoracostomy tube (TT) removal is highly variable and its utility is debated. We hypothesize that routine post-pull chest x-ray (PP-CXR) findings following TT removal in pediatric trauma would not guide the decision for TT reinsertion. METHODS: Patients ≤ 18 y who were not mechanically ventilated and undergoing final TT removal for a traumatic hemothorax (HTX) and/or pneumothorax (PTX) at a level I pediatric trauma center from 2010 to 2020 were retrospectively reviewed. The outcomes of interest were rate of PP-CXR and TT reinsertion rate following PP-CXR. Clinical predictors for worsened findings on PP-CXR were also assessed. RESULTS: Fifty-nine patients were included. A CXR after TT removal was performed in 57 patients (97%), with 28% demonstrating worsened CXR findings compared to the prior film. Except for higher ISS (p = 0.033), there were no demographic or clinical predictors for worsened CXR findings. However, they were more likely to have additional films following the TT removal (p = 0.008) than those with stable or improved PP-CXR findings. One (1.8%) asymptomatic child with worsened PP-CXR findings had TT reinsertion based purely on their worsened PP-CXR findings. CONCLUSIONS: The vast majority of PP-CXR did not guide TT reinsertion after pediatric thoracic trauma. Treatment algorithms may aid to reduce variability and potentially unnecessary routine films.

Influence of Growth Factors on the Development of Necrotizing Enterocolitis.

Growth factors have important roles in gastrointestinal tract development, maintenance, and response to injury. Various experiments have been used to demonstrate growth factor influence in multiple disease processes. These studies demonstrated enhancement of mucosal proliferation, intestinal motility, immune modulation, and many other beneficial effects. Select growth factors, including epidermal growth factor and heparin-binding epidermal growth factor like growth factor, demonstrate some beneficial effects in experimental and clinical intestinal injury demonstrated in necrotizing enterocolitis. The roles of glucagon-like peptide 2, insulin-like growth factor 1, erythropoietin, growth hormone, and hepatocyte growth factor in necrotizing enterocolitis are summarized in this article.

Comparison of polyglycolic acid, polycaprolactone, and collagen as scaffolds for the production of tissue engineered intestine.

Cell-seeded scaffolds play critical roles in the production of tissue engineered intestine (TEI), a potential strategy for the treatment of short bowel syndrome. The current study compares polyglycolic acid (PGA), polycaprolactone (PCL), and collagen as scaffolds for TEI production. Tubular PGA scaffolds were prepared from nonwoven BIOFELT® . Tubular PCL scaffolds were fabricated by electrospinning. Tubular collagen scaffolds were prepared using CollaTape, a wound dressing material. Both PGA and collagen were coated with poly-l-lactic acid (PLLA) to improve scaffold mechanical properties. Pore size, porosity, microstructure, mechanical properties (suture retention strength and ultimate compressive force) were determined. The scaffolds were first seeded with crypt stem cells isolated from 1 to 3 day old rat pups and then implanted into the peritoneal cavity of nude rats. After 4 weeks of in vivo incubation, these cell-seeded scaffolds were harvested for assessment of the TEI produced. Of the three materials compared, PLLA coated tubular PGA scaffolds had the appropriate pore size, mechanical properties and degradation rate leading to the production of TEI with an architecture similar to that of native rat intestine. © 2018 Wiley Periodicals, Inc. J. Biomed. Mater. Res. Part B, 2018. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 750-760, 2019.

Comparison of Different In Vivo Incubation Sites to Produce Tissue-Engineered Small Intestine.

OBJECTIVE: The objective of this study was to compare the impact of different in vivo incubation sites on the production of tissue-engineered small intestine (TESI). MATERIALS AND METHODS: Green fluorescent protein transgenic rat pups (3-5 days) were used as donors of intestinal organoids. Harvested intestine was exposed to enzymatic digestion to release intestinal stem cell-containing organoids. Organoids were purified, concentrated, and seeded onto tubular polyglycolic acid scaffolds. Seeded scaffolds were implanted in each of five locations in recipient female nude rats: wrapped with omentum, wrapped with intestinal mesentery, wrapped with uterine horn membrane, attached to the abdominal wall, and inserted into the subcutaneous space. After 4 weeks of in vivo incubation, specimens from each site were explanted for evaluation. RESULTS: Wrapping seeded scaffolds with vascularized membranes produced TESI with variable lengths of vascularized pedicles, with the longest pedicle length from uterine horn membrane, the shortest pedicle length from intestinal mesentery, and intermediate length from omentum. The quantity of TESI, as expressed by volume and neomucosal length, was identical in TESI produced by wrapping with any of the three membranes. The smallest quantity of TESI was found in TESI produced from insertion into the subcutaneous space, with an intermediate quantity of TESI produced from attachment to the abdominal wall. Periodic acid-Schiff and immunofluorescence (IF) staining confirmed the presence of all intestinal epithelial cell lineages in TESI produced at all incubation sites. Additional IF staining demonstrated the presence of enteric nervous system components and blood vessels. Wrapping of seeded scaffolds with vascularized membranes significantly increased the density of blood vessels in the TESI produced. CONCLUSION: Wrapping of seeded scaffolds in vascularized membranes produced the largest quantity and highest quality of TESI. Attaching seeded scaffolds to the abdominal wall produced an intermediate quantity of TESI, but the quality was still comparable to TESI produced in vascularized membranes. Insertion of seeded scaffolds into the subcutaneous space produced the smallest quantity and lowest quality of TESI. In summary, wrapping seeded scaffolds with vascularized membranes is favorable for the production of TESI, and wrapping with omentum may produce TESI that is most easily anastomosed with host intestine.

Critical intestinal cells originate from the host in enteroid-derived tissue-engineered intestine.

BACKGROUND: Enteroid-derived tissue-engineered intestine (TEI) contains intestinal subepithelial myofibroblasts (ISEMFs) and smooth muscle cells (SMCs). However, these cell types are not present in the donor enteroids. We sought to determine the origin of these cell types and to quantify their importance in TEI development. MATERIALS AND METHODS: Crypts from pan-EGFP or LGR5-EGFP mice were used for enteroid culture and subsequent implantation for the production of TEI. TEI from pan-EGFP enteroids was labeled for smooth muscle alpha actin (SMA) to identify ISEMFs and SMCs and green fluorescent protein (GFP) to identify cells from pan-EGFP enteroids. Fluorescence in situ hybridization (FISH) for the Y chromosome was applied to TEI from male LGR5-EGFP enteroids implanted into female nonobese diabetic/severe combined immunodeficiency mice. To identify chemotactic effects of intestinal epithelium on ISEMFs, a Boyden chamber assay was performed. RESULTS: Immunofluorescence of TEI from pan-EGFP enteroids revealed GFP-positive epithelium with surrounding SMA positivity and no colocalization of the two. FISH of TEI from male LGR5-EGFP enteroids implanted into female nonobese diabetic/severe combined immunodeficiency mice revealed that only the epithelium was Y chromosome positive. Chemotactic assays demonstrated increased ISEMF migration in the presence of enteroids (983 ± 133) compared to that in the presence of either Matrigel alone (357 ± 36) or media alone (339 ± 24; P ≤ 0.05). CONCLUSIONS: Lack of GFP/SMA colocalization suggests that ISEMFs and SMCs are derived from host animals. This was confirmed by FISH which identified only epithelial cells as being male. All other cell types originated from host animals. The mechanism by which these cells are recruited is unknown; however, Boyden chamber assays indicate a direct chemotactic effect of intestinal epithelium on ISEMFs.

Freeform fabrication of tissue-simulating phantom for potential use of surgical planning in conjoined twins separation surgery.

Preoperative assessment of tissue anatomy and accurate surgical planning is crucial in conjoined twin separation surgery. We developed a new method that combines three-dimensional (3D) printing, assembling, and casting to produce anatomic models of high fidelity for surgical planning. The related anatomic features of the conjoined twins were captured by computed tomography (CT), classified as five organ groups, and reconstructed as five computer models. Among these organ groups, the skeleton was produced by fused deposition modeling (FDM) using acrylonitrile-butadiene-styrene. For the other four organ groups, shell molds were prepared by FDM and cast with silica gel to simulate soft tissues, with contrast enhancement pigments added to simulate different CT and visual contrasts. The produced models were assembled, positioned firmly within a 3D printed shell mold simulating the skin boundary, and cast with transparent silica gel. The produced phantom was subject to further CT scan in comparison with that of the patient data for fidelity evaluation. Further data analysis showed that the produced model reassembled the geometric features of the original CT data with an overall mean deviation of less than 2 mm, indicating the clinical potential to use this method for surgical planning in conjoined twin separation surgery.

Facilitating surgeon understanding of complex anatomy using a three-dimensional printed model.

BACKGROUND: 3-dimensional prints (3DP) anecdotally facilitate surgeon understanding of anatomy and decision-making. However, the actual benefit to surgeons or patients has not been quantified. This study investigates how surgeon understanding of complex anatomy is altered by a 3DP compared to computed tomography (CT) scan or CT + digital reconstruction (CT + DR). MATERIALS AND METHODS: Key anatomic features were segmented from a CT-abdomen/pelvis of pygopagus twins to build a DR and printed in color on a 3D printer. Pediatric surgery trainees and attendings (n = 21) were tested regarding anatomy identification and their understanding of point-to-point distances, scale, and shape. RESULTS: There was no difference between media regarding point-to-point distances. The 3DP led to an increased number of correct answers for questions of scale and shape compared to CT (P < 0.05). CT + DR performance was intermediate but not statistically different from 3DP or CT. Identification of anatomy was inconsistent between media; however, answers were significantly closer to correct when using the 3DP. Participants completed the test faster with the 3DP (6.6 ± 0.5 min) (P < 0.05) than with CT (18.9 ± 2.5 min) or CT + 3DR (14.9 ± 1.5 min). CONCLUSIONS: Although point-to-point measurements were not different, 3DP increased the understanding of shape, scale, and anatomy. It enabled understanding significantly faster than other media. In difficult surgical cases with complex anatomy and a need for efficient multidisciplinary coordination, 3D printed models should be considered for surgical planning.

Identifying Adverse Events in Pediatric Surgery: Comparing Morbidity and Mortality Conference with the NSQIP-Pediatric System.

BACKGROUND: Recent improvements to morbidity and mortality (M&M) conference have focused on the case review system. However, case selection occurs by physician reporting, which is limited by selection bias. We compared the effectiveness of our M&M conference with the NSQIP-Pediatric (NSQIP-P) system for identifying adverse events. STUDY DESIGN: Complications from January 2010 to September 2015 were compared between M&M and NSQIP-P. Only M&M patients meeting NSQIP-P criteria were compared with patients from the NSQIP-P system; exclusions were studied separately. Complication rates in M&M conference before and after a 2012 format change designed to increase case reporting were also compared. RESULTS: Detection of mortality in M&M conference and NSQIP-P was not different. Morbidity events identified by NSQIP-P were significantly higher than M&M conference during the entire study period (194 vs 100 occurrences/1,000 cases) (p < 0.0001). Morbidity occurrences in M&M conference increased with the 2012 improvements, however, they still remained less than that identified by NSQIP-P (226 vs 141 occurrences/1,000 cases) (p < 0.0001). Of 863 patients presented in M&M conference, 210 were excluded from direct comparison because they did not meet NSQIP-P criteria. These included 62 deaths and 287 occurrences of morbidity. Their analysis in M&M conference resulted in 32 action initiatives directed at system failures. CONCLUSIONS: The NSQIP-P identified more complications than M&M. The M&M conference improvements increased reported cases, but they still remained lower than NSQIP-P. However, M&M conference identified events resulting in systems changes that would not have been identified by NSQIP-P. Although NSQIP-P captures occurrences to compare large patient cohorts, M&M analyzes singular failures and initiates direct interventions. Integration of these systems can optimize their usefulness in quality improvement.

Pygopagus Conjoined Twins: A Neurophysiologic Intraoperative Monitoring Schema.

Conjoined twins occur in up to 1 in 50,000 live births with approximately 18% joined in a pygopagus configuration at the buttocks. Twins with this configuration display symptoms and carry surgical risks during separation related to the extent of their connection which can include anorectal, genitourinary, vertebral, and neural structures. Neurophysiologic intraoperative monitoring for these cases has been discussed in the literature with variable utility. The authors present a case of pygopagus twins with fused spinal cords and imperforate anus where the use of neurophysiologic intraoperative monitoring significantly impacted surgical decision-making in division of these critical structures.

HB-EGF embedded in PGA/PLLA scaffolds via subcritical CO2 augments the production of tissue engineered intestine.

The ability to deliver sustained-release, biologically active growth factors through custom designed tissue engineering scaffolds at sites of tissue regeneration offers great therapeutic opportunity. Due to the short in vivo half-lives of most growth factors, it is challenging to deliver these proteins to sites of interest where they may be used before being degraded. The application of subcritical CO2 uses gas-phase CO2 at subcritical pressures ranging from 41 to 62 bar (595-913 PSI) which avoids foaming by reducing the amount of CO2 dissolved in the polymer and maintains completely reversible plasticization. In the current study, heparin-binding EGF-like growth factor (HB-EGF) was embedded into polyglycolic acid (PGA)/Poly-l-latic acid (PLLA) scaffolds via subcritical CO2 exposure for the production of tissue engineered intestine (TEI). PGA fiber morphology after subcritical CO2 exposure was examined by scanning electron microscopy (SEM) and the distribution of HB-EGF embedded in the scaffold fibers was detected by HB-EGF immunofluorescent staining. In vivo implantation of HB-EGF-embedded scaffolds confirmed significantly improved TEI structure as a result of local delivery of the trophic growth factor. These findings may be critical for the production of TEI in the treatment of patients with short bowel syndrome in the future.

Production of tissue-engineered intestine from expanded enteroids.

BACKGROUND: Short bowel syndrome is a life-threatening condition with few solutions. Tissue-engineered intestine (TEI) is a potential treatment, but donor intestine is a limiting factor. Expanded epithelial surrogates termed enteroids may serve as a potential donor source. MATERIALS AND METHODS: To produce TEI from enteroids, crypts were harvested from mice and enteroid cultures established. Enteroids were seeded onto polymer scaffolds using Matrigel or culture medium and implanted in immunosuppressed mice for 4 wk. Histology was analyzed using Periodic acid-Schiff staining and immunofluorescence. Neomucosa was quantified using ImageJ software. To determine whether TEI could be produced from enteroids established from small intestinal biopsies, 2 × 2-mm pieces of jejunum were processed for enteroid culture, enteroids were expanded and seeded onto scaffolds, and scaffolds implanted for 4 wk. RESULTS: Enteroids in Matrigel produced TEI in 15 of 15 scaffolds, whereas enteroids in medium produced TEI in 9 of 15 scaffolds. Use of Matrigel led to more neomucosal surface area compared to media (10,520 ± 2905 µm versus 450 ± 127 µm, P < 0.05). Histologic examination confirmed the presence of crypts and blunted villi, normal intestinal epithelial lineages, intestinal subepithelial myofibroblasts, and smooth muscle cells. Crypts obtained from biopsies produced an average of 192 ± 71 enteroids. A single passage produced 685 ± 58 enteroids, which was adequate for scaffold seeding. TEI was produced in 8 of 9 scaffolds seeded with expanded enteroids. CONCLUSIONS: Enteroids can be obtained from minimal starting material, expanded ex vivo, and implanted to produce TEI. This method shows promise as a solution to the limited donor intestine available for TEI production in patients with short bowel syndrome.

Implementation of a pediatric surgical quality improvement (QI)-driven M&M conference.

BACKGROUND/PURPOSE: The M&M conference at Nationwide Children's Hospital (NCH) categorized failures as technical error or patient disease, but failure modes were never captured, action items rarely assigned, and follow-up rarely completed. In 2013 a QI-driven M&M conference was developed, supporting implementation of directed actions to improve quality of care. METHODS: A classification was developed to enhance analysis of complications. Each complication was analyzed for identification of failure modes with subcategorization of root cause, a level of preventability assigned, and action items designated. Failure determinations from 11/2013-10/2014 were reviewed to evaluate the distribution of failure modes and action items. RESULTS: Two-hundred thirty-seven patients with complications were reviewed. One-hundred thirty patients had complications attributed to patient disease with no individual or system failure identified, whereas 107 patients had identifiable failures. Eighty-five patients had one failure identified, and 22 patients had multiple failures identified. Of the 142 failures identified in 107 patients, 112 (78.9%) were individual failures, and 30 (21.1%) were system failures. One-hundred forty-seven action items were implemented including education initiatives, establishing criteria for interdisciplinary consultation, resolving equipment inadequacies, removing high risk medications from formulary, restructuring physician handoffs, and individual practitioner counseling/training. CONCLUSIONS: Development of a QI-driven M&M conference allowed us to categorize complications beyond surgical or patient disease categories, ensuring added focus on system solutions and a reliable accountability structure to ensure implementation of assigned interventions intended to address failures. This may lead to improvement in the processes of patient care.

An attachment-based description of the medial collateral and spring ligament complexes.

BACKGROUND: Anatomy of the medial collateral and spring ligament complexes has been the cause of confusion. The anatomic description is highly dependent on the source studied and little agreement exists between texts. In addition, inconsistent nomenclature has been used to describe the components. This study attempted to clarify confusion through the creation of a 3D ligament map using attachment-based dissection. METHODS: Nine fresh foot and ankle specimens were observed. The medial collateral ligament and spring ligament complexes were dissected using their attachment sites as a guide to define individual components. Each component's perimeter and thickness was measured and each bony attachment was mapped using a microscribe 3D digitizer. RESULTS: Five components were identified contributing to the ligament complexes of interest: the tibiocalcaneonavicular, superficial posterior tibiotalar, deep posterior tibiotalar, deep anterior tibiotalar, and inferoplantar longitudinal ligaments. The largest component by total attachment area was the tibiocalcaneonavicular ligament followed by the deep posterior tibiotalar ligament. The largest ligament surface area of attachment to the tibia and talus was the deep posterior tibiotalar ligament. The largest attachment to the navicular and calcaneus was the tibiocalcaneonavicular ligament, which appeared to function in holding these bones in proximity while supporting the head of the talus. CONCLUSION: By defining complex components by their attachment sites, a novel, more functional and reproducible description of the medial collateral and spring ligament complexes was created. CLINICAL RELEVANCE: The linear measurements and 3D maps may prove useful when attempting more anatomically accurate reconstructions.

Association of hindfoot ligament tears and osteochondral lesions.

BACKGROUND: This study aimed to identify the prevalence of ligament and joint surface anatomy variants, ligament tears, and osteochondral lesions (OCLs) in the hindfoot. These data were used to identify associations between anatomic variants or ligament tears and OCLs. METHODS: Seventy-two cadaver hindfoot specimens were examined. Hindfoot ligament presence, number of ligament fascicles, variable ligament attachment sites, ligament tears, presence of joint facets, variable joint surface shape, and the location and grade of OCLs were identified in each specimen. The data were analyzed for significant associations between variables. RESULTS: Fourteen of the 30 studied ligaments were always present and 14 had variable number of fascicles. The lateral talocalcaneal and dorsolateral calcaneocuboid ligaments had varying positional attachments. Osteochondral lesions were present in 86% of specimens with the majority in the talocrural joint. Of the 235 lesions identified, 31 were grade 3 or above. Ligament tears occurred in 2% of all ligaments observed. Tears in the lateral talocalcaneal, medial calcaneocuboid, and dorsolateral calcaneocuboid ligaments were associated with an increased number of hindfoot OCLs. CONCLUSION: We demonstrated the prevalence of morphologic ligament and joint surface variants, ligament tears, and osteochondral lesions in the hindfoot. Tears in ligaments stabilizing the calcaneocuboid joint were implicated in an increase in hindfoot joint damage. CLINICAL RELEVANCE: We believe anatomic studies can be used to clarify the association between traumatic injuries and their sequelae.