Management of undifferentiated embryonal sarcoma of the liver: A Pediatric Surgical Oncology Research Collaborative study.

BACKGROUND: Undifferentiated embryonal sarcoma of the liver (UESL) is a rare tumor for which there are few evidence-based guidelines. The aim of this study was to define current management strategies and outcomes for these patients using a multi-institutional dataset curated by the Pediatric Surgical Oncology Research Collaborative. METHODS: Data were collected retrospectively for patients with UESL treated across 17 children's hospitals in North America from 1989 to 2019. Factors analyzed included patient and tumor characteristics, PRETEXT group, operative details, and neoadjuvant/adjuvant regimens. Event-free and overall survival (EFS, OS) were the primary and secondary outcomes, respectively. RESULTS: Seventy-eight patients were identified with a median age of 9.9 years [interquartile range [IQR): 7-12]. Twenty-seven patients underwent resection at diagnosis, and 47 patients underwent delayed resection, including eight liver transplants. Neoadjuvant chemotherapy led to a median change in maximum tumor diameter of 1.6 cm [IQR: 0.0-4.4] and greater than 90% tumor necrosis in 79% of the patients undergoing delayed resection. R0 resections were accomplished in 63 patients (81%). Univariate analysis found that metastatic disease impacted OS, and completeness of resection impacted both EFS and OS, while multivariate analysis revealed that R0 resection was associated with decreased expected hazards of experiencing an event [hazard ratio (HR): 0.14, 95% confidence interval (CI): 0.04-0.6]. At a median follow-up of 4 years [IQR: 2-8], the EFS was 70.0% [95% CI: 60%-82%] and OS was 83% [95% CI: 75%-93%]. CONCLUSION: Complete resection is associated with improved survival for patients with UESL. Neoadjuvant chemotherapy causes minimal radiographic response, but significant tumor necrosis.

Gender trends in applicants to general surgery residency programs in Canada.

BACKGROUND: Surgical disciplines lag behind non-surgical disciplines in attracting female trainees. Female representation of Canadian General Surgeons has not been evaluated in recent years in the literature. The objectives of this study were to assess gender trends in applicants to Canadian General Surgery residency programs and practicing general surgeons and subspecialists. METHODS: This retrospective cross-sectional study analyzed gender data for residency applicants ranking General Surgery as their first-choice discipline from publicly-available annual Canadian Residency Matching Service (CaRMS) R-1 match reports from 1998 to 2021. Aggregate gender data for practicing female physicians in General Surgery and related subspecialties, including Pediatric Surgery, obtained from annual Canadian Medical Association (CMA) census from 2000 to 2019 was also analysed. RESULTS: There was a significant increase in the proportion of female applicants from 34% in 1998 to 67% in 2021 (p < 0.001) and of successfully matched candidates from 39% to 68% (p = 0.002) from 1998 to 2021. Success rates between male and female candidates were significantly different in 1998 (p < 0.001), but not in 2021 (p = 0.29). The proportion of practicing female General Surgeons also significantly increased from 10.1% in 2000 to 27.9% in 2019 (p = 0.0013), with variable trends in subspecialties. CONCLUSION: Gender inequality in General Surgery residency matches has normalized since 1998. Despite females representing more than 40% of applicants and successfully matched candidates to General Surgery since 2008, a gender gap still exists amongst practicing General Surgeons and subspecialists. This suggests the need for further cultural and systemic change to mitigate gender disparities. TYPE OF STUDY: Original research article, clinical research. LEVEL OF EVIDENCE: Level III (Retrospective cross-sectional study).

The metabolic and lipidomic profiling of the effects of tracheal occlusion in a rabbit model of congenital diaphragmatic hernia.

PURPOSE: Fetal tracheal occlusion (TO) reverses the pulmonary hypoplasia associated with congenital diaphragmatic hernia (CDH), but its mechanism of action remains poorly understood. 'Omic' readouts capture metabolic and lipid processing function, which aid in understanding CDH and TO metabolic mechanisms. METHODS: CDH was created in fetal rabbits at 23 days, TO at 28 days and lung collection at 31 days (Term ∼32 days). Lung-body weight ratio (LBWR) and mean terminal bronchiole density (MTBD) were determined. In a cohort, left and right lungs were collected, weighed, and samples homogenized, and extracts collected for non-targeted metabolomic and lipidomic profiling via LC-MS and LC-MS/MS, respectively. RESULTS: LBWR was significantly lower in CDH while CDH + TO was similar to controls (p = 0.003). MTBD was significantly higher in CDH fetuses and restored to control and sham levels in CDH + TO (p < 0.001). CDH and CDH + TO resulted in significant differences in metabolome and lipidome profiles compared to sham controls. A significant number of altered metabolites and lipids between the controls and CDH groups and the CDH and CDH + TO fetuses were identified. Significant changes in the ubiquinone and other terpenoid-quinone biosynthesis pathway and the tyrosine metabolism pathway were observed in CDH + TO. CONCLUSION: CDH + TO reverses pulmonary hypoplasia in the CDH rabbit, in association with a specific metabolic and lipid signature. A synergistic untargeted 'omics' approach provides a global signature for CDH and CDH + TO, highlighting cellular mechanisms among lipids and other metabolites, enabling comprehensive network analysis to identify critical metabolic drivers in disease pathology and recovery. TYPE OF STUDY: Basic Science, Prospective. LEVEL OF EVIDENCE: II.

The influence of surgical and procedural rotations and interest in a surgical discipline on medical students' suturing ability during clerkship.

BACKGROUND: Although suturing is an essential competency for medical students, there has been limited research into the skills acquisition process over the course of medical school curriculum. This study aimed to determine whether suturing ability improved over the course of clerkship and whether an interest in a surgical discipline was associated with improved skill acquisition. METHODS: The suturing ability of third-year medical students at a large Canadian medical school was assessed at the beginning of clerkship (August 2018) as well as before and after their surgery rotation by 2 expert reviewers using a validated, objective scoring system as well as a qualitative assessment, both in person and via blinded video recordings. Students were randomly allocated to 4 groups for their clerkship year by the medical school. RESULTS: Of 133 eligible students, 115 (86.5%) completed the study. Median suturing assessment scores improved significantly after the surgery rotation (214.5 [interquartile range (IQR) 191.1-235.0] v. 238.0 [IQR 223.5-255.0], p = 0.001). Groups that had completed a procedural rotation (emergency medicine, obstetrics and gynecology) between clerkship and starting their surgery rotation had improved scores between these time points (p < 0.05), whereas scores decreased for groups that did not have a procedural rotation between assessments. Regardless of previous rotations, suturing scores were similar between groups after the surgery rotation. The 21 students (18.3%) who were interested in a surgical discipline had higher suturing scores than students who were not interested in surgery at the beginning of clerkship (229.1 [IQR 220.2-253.0] v. 208.0 [IQR 185.0-228.0], p < 0.001) and after the surgery rotation (252.0 [IQR 227.0-268.0] v. 235.8 [IQR 220.5-251.2], p = 0.02). CONCLUSION: Medical students' suturing ability improved during the surgery rotation but was also influenced by other procedural rotations and students' interest in procedure specialties. Skill acquisition by medical students is complex and requires additional investigation.

Histologic type predicts disparate outcomes in pediatric hepatocellular neoplasms: A Pediatric Surgical Oncology Research Collaborative study.

BACKGROUND: Hepatocellular carcinoma (HCC) is a rare cancer in children, with various histologic subtypes and a paucity of data to guide clinical management and predict prognosis. METHODS: A multi-institutional review of children with hepatocellular neoplasms was performed, including demographic, staging, treatment, and outcomes data. Patients were categorized as having conventional HCC (cHCC) with or without underlying liver disease, fibrolamellar carcinoma (FLC), and hepatoblastoma with HCC features (HB-HCC). Univariate and multivariate analyses identified predictors of mortality and relapse. RESULTS: In total, 262 children were identified; and an institutional histologic review revealed 110 cHCCs (42%; 69 normal background liver, 34 inflammatory/cirrhotic, 7 unknown), 119 FLCs (45%), and 33 HB-HCCs (12%). The authors observed notable differences in presentation and behavior among tumor subtypes, including increased lymph node involvement in FLC and higher stage in cHCC. Factors associated with mortality included cHCC (hazard ratio [HR], 1.63; P = .038), elevated α-fetoprotein (HR, 3.1; P = .014), multifocality (HR, 2.4; P < .001), and PRETEXT (pretreatment extent of disease) stage IV (HR, 5.76; P < .001). Multivariate analysis identified increased mortality in cHCC versus FLC (HR, 2.2; P = .004) and in unresectable tumors (HR, 3.4; P < .001). Disease-free status at any point predicted survival. CONCLUSIONS: This multi-institutional, detailed data set allowed a comprehensive analysis of outcomes for children with these rare hepatocellular neoplasms. The current data demonstrated that pediatric HCC subtypes are not equivalent entities because FLC and cHCC have distinct anatomic patterns and outcomes in concert with their known molecular differences. This data set will be further used to elucidate the impact of histology on specific treatment responses, with the goal of designing risk-stratified algorithms for children with HCC. LAY SUMMARY: This is the largest reported granular data set on children with hepatocellular carcinoma. The study evaluates different subtypes of hepatocellular carcinoma and identifies key differences between subtypes. This information is pivotal in improving understanding of these rare cancers and may be used to improve clinical management and subsequent outcome in children with these rare malignancies.

Inflammatory myofibroblastic tumor: A multi-institutional study from the Pediatric Surgical Oncology Research Collaborative.

Inflammatory myofibroblastic tumor (IMT) is a mesenchymal neoplasm of intermediate malignancy. We describe the largest cohort of IMT patients to date, aiming to further characterize this rare, poorly understood tumor. This is a multi-institutional review of IMT patients ≤39 years, from 2000 to 2018, at 18 hospitals in the Pediatric Surgical Oncology Research Collaborative. One hundred and eighty-two patients were identified with median age of 11 years. Thirty-three percent of tumors were thoracic in origin. Presenting signs/symptoms included pain (29%), respiratory symptoms (25%) and constitutional symptoms (20%). Median tumor size was 3.9 cm. Anaplastic lymphoma kinase (ALK) overexpression was identified in 53% of patients. Seven percent of patients had distant disease at diagnosis. Ninety-one percent of patients underwent resection: 14% received neoadjuvant treatment and 22% adjuvant treatment. Twelve percent of patients received an ALK inhibitor. Sixty-six percent of surgical patients had complete resection, with 20% positive microscopic margins and 14% gross residual disease. Approximately 40% had en bloc resection of involved organs. Median follow-up time was 36 months. Overall 5-year survival was 95% and 5-year event-free survival was 80%. Predictors of recurrence included respiratory symptoms, tumor size and distant disease. Gross or microscopic margins were not associated with recurrence, suggesting that aggressive attempts at resection may not be warranted.

Differentiating congenital ovarian cysts from other abdominal cystic lesions in female infants: A study by the Canadian Consortium for Research in Pediatric Surgery (CanCORPS).

PURPOSE: The origin of congenital abdominal cysts in the female fetus often dictates management. While most arise from the ovary and are often managed non-operatively, some are non-ovarian and are frequently removed. We analyzed a national sample of female infants with congenital abdominal cysts to elucidate prenatal and postnatal factors associated with the diagnosis of a non-ovarian cyst. METHODS: A retrospective cohort study of female infants who were prenatally diagnosed with abdominal cysts between 2013 and 2017 at 10 Canadian pediatric surgical centres was performed. Clinical characteristics, pre- and postnatal sonographic findings, and cyst trajectories were compared between patients with proven ovarian etiology and those with cysts arising from other organs. RESULTS: Of 185 infants with prenatally diagnosed abdominal cysts, 22 (12%) were non-ovarian, five of which had clear non-ovarian organ of origin on prenatal ultrasound. Comparison of the other 17 cysts with 163 congenital ovarian cysts showed the following factors to be associated with a non-ovarian origin: earlier gestational age at diagnosis (23.5 vs 33.5 weeks, p <0.001), smaller diameter on first prenatal ultrasound (15.8 vs. 39.7 mm, p <0.001), change in sonographic character from simple to complex (87% vs 22%, p <0.001), and postnatal sonographic characteristics of complex cyst (87% vs. 48%, p = 0.004). CONCLUSION: Clear organ of origin, diagnosis earlier in gestation, smaller initial prenatal cyst diameter, and sonographic cyst character change differentiate congenital non-ovarian cysts from their ovarian counterparts. These characteristics may be used to guide diagnosis and management.

Implications of Tumor Characteristics and Treatment Modality on Local Recurrence and Functional Outcomes in Children With Chest Wall Sarcoma: A Pediatric Surgical Oncology Research Collaborative Study.

OBJECTIVE: To determine the impact of tumor characteristics and treatment approach on (1) local recurrence, (2) scoliosis development, and (3) patient-reported quality of life in children with sarcoma of the chest wall. SUMMARY OF BACKGROUND DATA: Children with chest wall sarcoma require multimodal therapy including chemotherapy, surgery, and/or radiation. Despite aggressive therapy which places them at risk for functional impairment and scoliosis, these patients are also at significant risk for local recurrence. METHODS: A multi-institutional review of 175 children (median age 13 years) with chest wall sarcoma treated at seventeen Pediatric Surgical Oncology Research Collaborative institutions between 2008 and 2017 was performed. Patient-reported quality of life was assessed prospectively using PROMIS surveys. RESULTS: The most common diagnoses were Ewing sarcoma (67%) and osteosarcoma (9%). Surgical resection was performed in 85% and radiation in 55%. A median of 2 ribs were resected (interquartile range = 1-3), and number of ribs resected did not correlate with margin status ( P = 0.36). Local recurrence occurred in 23% and margin status was the only predictive factor(HR 2.24, P = 0.039). With a median follow-up of 5 years, 13% developed scoliosis (median Cobb angle 26) and 5% required corrective spine surgery. Scoliosis was associated with posteriorrib resection (HR 8.43; P= 0.003) and increased number of ribs resected (HR 1.78; P = 0.02). Overall, patient-reported quality of life is not impaired after chest wall tumor resection. CONCLUSIONS: Local recurrence occurs in one-quarter of children with chest wall sarcoma and is independent of tumor type. Scoliosis occurs in 13% of patients, but patient-reported quality of life is excellent.

Appendectomy Versus Observation for Appendicitis in Neutropenic Children With Cancer.

BACKGROUND: Optimal management of neutropenic appendicitis (NA) in children undergoing cancer therapy remains undefined. Management strategies include upfront appendectomy or initial nonoperative management. We aimed to characterize the effect of management strategy on complications and length of stay (LOS) and describe implications for chemotherapy delay or alteration. METHODS: Sites from the Pediatric Surgery Oncology Research Collaborative performed a retrospective review of children with NA over a 6-year period. RESULTS: Sixty-six children, with a median age of 11 years (range 1-17), were identified with NA while undergoing cancer treatment. The most common cancer diagnoses were leukemia (62%) and brain tumor (12%). Upfront appendectomy was performed in 41% of patients; the remainder had initial nonoperative management. Rates of abscess or perforation at diagnosis were equivalent in the groups (30% vs 24%; P = .23). Of patients who had initial nonoperative management, 46% (17 of 37) underwent delayed appendectomy during the same hospitalization. Delayed appendectomy was due to failure of initial nonoperative management in 65% (n = 11) and count recovery in 35% (n = 6). Cancer therapy was delayed in 35% (n = 23). Initial nonoperative management was associated with a delay in cancer treatment (46% vs. 22%, P = .05) and longer LOS (29 vs 12 days; P = .01). Patients who had initial nonoperative management and delayed appendectomy had a higher rate of postoperative complications (P < .01). CONCLUSIONS: In pediatric patients with NA from oncologic treatment, upfront appendectomy resulted in lower complication rates, reduced LOS, and fewer alterations in chemotherapy regimens compared to initial nonoperative management.

Gender Disparities in Medical Student Surgical Skills Education.

OBJECTIVE: Female medical students and surgical trainees are more likely to lack confidence in their clinical abilities than their male peers despite equal or superior performance. This study aims to examine the role of gender in medical student experience and confidence performing technical skills in surgical clerkship. DESIGN: This was a single-center survey study conducted over 2 academic years (2016-2018). Students were surveyed on their experience and confidence performing a set of 9 technical skills during surgical clerkship and to identify skill-specific barriers to learning. SETTING: This study was performed at Western University, London, Ontario, Canada. PARTICIPANTS: All third-year medical students were invited to participate. RESULTS: A total of 253 students participated yielding a survey response rate of 74.0%. Both male and female students reported similar levels of preclerkship interest in a surgical career, enjoyment in performing technical skills, confidence in ability to learn surgical skills and pursuit of available learning opportunities. At the conclusion of their surgical rotations, female students reported less experience and confidence performing technical skills compared to their male colleagues. Female students were more likely to cite an insufficient number of learning opportunities from consultant and resident teachers, time constraints, and lack of confidence as barriers to the achievement of technical proficiency. CONCLUSIONS: Female gender was associated with less procedural experience and inferior confidence performing procedural skills. It is important for educators to be aware of this gender disparity and to actively promote equitable learning opportunities for female trainees.

Thoracoscopy vs thoracotomy for the management of metastatic osteosarcoma: A Pediatric Surgical Oncology Research Collaborative Study.

Complete surgical resection of pulmonary metastatic disease in patients with osteosarcoma is crucial to long-term survival. Open thoracotomy allows palpation of nodules not identified on imaging but the impact on survival is unknown. The objective of this study was to compare overall survival (OS) and pulmonary disease-free survival (DFS) in children who underwent thoracotomy vs thoracoscopic surgery for pulmonary metastasectomy. A multi-institutional collaborative group retrospectively reviewed 202 pediatric patients with osteosarcoma who underwent pulmonary metastasectomy by thoracotomy (n = 154) or thoracoscopy (n = 48). Results were analyzed by Kaplan-Meier survival estimates and multivariate Cox proportional hazard regression models. With median follow-up of 45 months, 135 (67.5%) patients had a pulmonary relapse and 95 (47%) patients were deceased. Kaplan-Meier analysis showed no significant difference in 5-year pulmonary DFS (25% vs 38%; P = .18) or OS (49% vs 42%, P = .37) between the surgical approaches of thoracotomy and thoracoscopy. In Cox regression analysis controlling for other factors impacting outcome, there was a significantly increased risk of mortality (HR 2.11; P = .027; 95% CI 1.09-4.09) but not pulmonary recurrence (HR 0.96; P = .90; 95% CI 0.52-1.79) with a thoracoscopic approach. However, in the subset analysis limited to patients with oligometastatic disease, thoracoscopy had no increased risk of mortality (HR 1.16; P = .62; 0.64-2.11). In conclusion, patients with metastatic osteosarcoma and limited pulmonary disease burden demonstrate comparable outcomes after thoracotomy and thoracoscopy for metastasectomy. While significant selection bias in these surgical cohorts limits the generalizability of the conclusions, clinical equipoise for a randomized clinical trial in patients with oligometastatic disease is supported.

Hyoscine butylbromide versus acetaminophen for nonspecific colicky abdominal pain in children: a randomized controlled trial.

BACKGROUND: Less than two-thirds of children with abdominal pain in the emergency department receive analgesia. We sought to determine whether hyoscine butylbromide was superior to acetaminophen for children with nonspecific colicky abdominal pain. METHODS: We randomly allocated children aged 8-17 years with nonspecific colicky abdominal pain who presented to the pediatric emergency department of London Health Sciences Centre, London, Ontario to receive hyoscine butylbromide, 10 mg given orally, or acetaminophen, 15 mg/kg given orally (maximum 975 mg). We considered the minimal clinically important difference for the primary outcome (self-reported pain at 80 min) to be 13 mm on a 100 mm visual analogue scale. Secondary outcomes included administration of rescue analgesia, adverse effects and pain score less than 30 mm at 80 minutes. RESULTS: A total of 236 participants (120 in the hyoscine butylbromide group and 116 in the acetaminophen group) were included in the trial. The mean visual analogue scale scores at 80 minutes were 29 mm (standard deviation [SD] 26 mm) and 30 mm (SD 29 mm) with hyoscine butylbromide and acetaminophen, respectively (adjusted difference 1, 95% confidence interval -7 to 7). Rescue analgesia was administered to 4 participants (3.3%) in the hyoscine butylbromide group and 1 participant (0.9%) in the acetaminophen groups (p = 0.2). We found no significant differences in rates of adverse effects between hyoscine butylbromide (32/116 [27.6%]) and acetaminophen (28/115 [24.3]) (p = 0.5); no serious adverse effects were observed. The proportion with a pain score less than 30 mm at 80 minutes was 66 (55.0%) with hyoscine butylbromide and 63 (54.3%) with acetaminophen (p = 0.9). INTERPRETATION: Hyoscine butylbromide was not superior to acetaminophen in this setting. Both agents were associated with clinically important pain reduction, and either can be considered for children presenting to the emergency department with nonspecific colicky abdominal pain. Trial registration: Clinicaltrials.gov, no. NCT02582307.

Pancreaticoduodenectomy for the treatment of pancreatic neoplasms in children: A Pediatric Surgical Oncology Research Collaborative study.

BACKGROUND: To better characterize short-term and long-term outcomes in children with pancreatic tumors treated with pancreaticoduodenectomy (PD). METHODS: Patients 21 years of age or younger who underwent PD at Pediatric Surgical Oncology Collaborative (PSORC) hospitals between 1990 and 2017 were identified. Demographic, clinical information, and outcomes (operative complications, long-term pancreatic function, recurrence, and survival) were collected. RESULTS: Sixty-five patients from 18 institutions with a median age of 13 years (4 months-22 years) and a median (IQR) follow-up of 2.8 (4.3) years were analyzed. Solid pseudopapillary tumor of the pancreas (SPN) was the most common histology. Postoperative complications included pancreatic leak in 14% (n = 9), delayed gastric emptying in 9% (n = 6), marginal ulcer in one patient, and perioperative (30-day) death due to hepatic failure in one patient. Pancreatic insufficiency was observed in 32% (n = 21) of patients, with 23%, 3%, and 6% with exocrine, or endocrine insufficiencies, or both, respectively. Children with SPN and benign neoplasms all survived. Overall, there were 14 (22%) recurrences and 11 deaths (17%). Univariate analysis revealed non-SPN malignant tumor diagnosis, preoperative vascular involvement, intraoperative transfusion requirement, pathologic vascular invasion, positive margins, and need for neoadjuvant chemotherapy as risk factors for recurrence and poor survival. Multivariate analysis only revealed pathologic vascular invasion as a risk factor for recurrence and poor survival. CONCLUSION: This is the largest series of pediatric PD patients. PD is curative for SPN and benign neoplasms. Pancreatic insufficiency is the most common postoperative complication. Outcome is primarily associated with histology.

Optimization of percutaneous biopsy for diagnosis and pretreatment risk assessment of neuroblastoma.

BACKGROUND: Image-guided percutaneous core needle biopsy (PCNB) is increasingly utilized to diagnose solid tumors. The objective of this study is to determine whether PCNB is adequate for modern biologic characterization of neuroblastoma. PROCEDURE: A multi-institutional retrospective study was performed by the Pediatric Surgical Oncology Research Collaborative on children with neuroblastoma at 12 institutions over a 3-year period. Data collected included demographics, clinical details, biopsy technique, complications, and adequacy of biopsies for cytogenetic markers utilized by the Children's Oncology Group for risk stratification. RESULTS: A total of 243 children were identified with a diagnosis of neuroblastoma: 79 (32.5%) tumor excision at diagnosis, 94 (38.7%) open incisional biopsy (IB), and 70 (28.8%) PCNB. Compared to IB, there was no significant difference in ability to accurately obtain a primary diagnosis by PCNB (95.7% vs 98.9%, P = .314) or determine MYCN copy number (92.4% vs 97.8%, P = .111). The yield for loss of heterozygosity and tumor ploidy was lower with PCNB versus IB (56.1% vs 90.9%, P < .05; and 58.0% vs. 88.5%, P < .05). Complications did not differ between groups (2.9 % vs 3.3%, P = 1.000), though the PCNB group had fewer blood transfusions and lower opioid usage. Efficacy of PCNB was improved for loss of heterozygosity when a pediatric pathologist evaluated the fresh specimen for adequacy. CONCLUSIONS: PCNB is a less invasive alternative to open biopsy for primary diagnosis and MYCN oncogene status in patients with neuroblastoma. Our data suggest that PCNB could be optimized for complete genetic analysis by standardized protocols and real-time pathology assessment of specimen quality.

Perceived Barriers to the Development of Technical Skill Proficiency in Surgical Clerkship.

OBJECTIVE: Medical students are expected to achieve proficiency in a prescribed set of technical skills during surgical clerkship. However, available literature indicates students routinely report a lack of confidence and proficiency in these skills. Our study aims to identify barriers to technical skill development encountered by medical students during surgical clerkship with the goal of developing interventions to address these barriers. DESIGN: Three hundred and forty two medical students were surveyed about their experience learning and performing technical skills during surgical clerkship. Students reported confidence in skill performance and subjective barriers to achieving competency using forced-choice and free-text responses. Multivariate regression models identified factors independently associated with specific barriers and more frequent technical skills performance. SETTING: Main and satellite campuses of a Medical Council of Canada accredited Canadian academic medical center. PARTICIPANTS: All third-year medical students. RESULTS: A total of 253 students (74%) responded to the survey. Following surgical clerkship, the only technical skills participants felt confident performing independently were sterile technique (96%) and basic suturing (52%). Interest in a surgical career, observership experience, gender, and medical campus site were independently associated with the frequency of skill performance. With respect to developing technical proficiency, commonly cited barriers included lack of suitable cases for student participation (35.0%), time constraints (33.4%), and lack of opportunities provided by both consultants (29.1%) and residents (24.7%). Female gender was independently associated with decreased resident instruction, decreased confidence in skill performance, and fewer opportunities to perform requisite skills. Students at satellite campuses reported fewer barriers. CONCLUSIONS: We identified (1) lack of suitable cases, (2) time constraints, and (3) failure to provide students opportunities as the most common barriers to technical skill proficiency. Female gender increased the perception of barriers, while there were fewer barriers perceived by students at satellite campuses. Skill-specific simulation training and other interventions may improve skill development in medical students given obstacles to developing proficiency in the clinical setting.

Outcomes of extracorporeal, transumbilical versus intracorporeal laparoscopic appendectomy for acute uncomplicated appendicitis in children and adolescents: A retrospective observational cohort study.

BACKGROUND: An extracorporeal (ECA), transumbilical appendectomy has been proposed as a treatment for appendicitis. This study assessed the 30-day perioperative outcomes and cost between ECA and traditional intracorporeal (ICA) techniques for acute uncomplicated appendicitis. METHODS: IRB approval was obtained for this retrospective cohort study of acute uncomplicated appendicitis in children aged 4 to 17 between April 2014 and April 2017. Patients were grouped based on ICA versus ECA. Operative time, length of stay, and complication rates were recorded. RESULTS: A total of 289 patients were included, and of these 217 underwent ICA, and 72 underwent ECA. Median weight-for-age percentile was the only demographic characteristic different between groups (ECA 50 [0.1-100] vs. ICA 71 [0-100]; p < 0.01). Median operative time was significantly shorter in the ECA group (21.0 min [8.0-61.0] vs. 38.0 min [19.0-87.0]; p < 0.0001). Length of stay and complication rates were similar between groups. The median per case cost was significantly lower in the ECA group (CAD$ 593.05 range: 499.70-900.81 vs. CAD$ 858.78 range: 490.36-1106.29; p < 0.001). CONCLUSIONS: Extracorporeal transumbilical laparoscopic appendectomy is associated with shorter operative times and no increased risk of 30-day postoperative complications in children and adolescents. This offers a new operative approach that may reduce hospital cost and resources. LEVEL OF EVIDENCE: III.

The effects of tracheal occlusion on Wnt signaling in a rabbit model of congenital diaphragmatic hernia.

PURPOSE: Tracheal occlusion (TO) reverses pulmonary hypoplasia (PH) in congenital diaphragmatic hernia (CDH), but its mechanism of action remains poorly understood. Wnt signaling plays a critical role in lung development, but few studies exist. The purpose of our study was to a) confirm that our CDH rabbit model produced PH which was reversed by TO and b) determine the effects of CDH +/- TO on Wnt signaling. METHODS: CDH was created in fetal rabbits at 23 days, TO at 28 days, and lung collection at 31 days. Lung body weight ratio (LBWR) and mean terminal bronchiole density (MTBD) were determined. mRNA and miRNA expression was determined in the left lower lobe using RT-qPCR. RESULTS: Fifteen CDH, 15 CDH + TO, 6 sham CDH, and 15 controls survived and were included in the study. LBWR was low in CDH, while CDH + TO was similar to controls (p = 0.003). MTBD was higher in CDH fetuses and restored to control levels in CDH + TO (p < 0.001). Reference genes TOP1, SDHA, and ACTB were consistently expressed within and between treatment groups. miR-33 and MKI67 were increased, and Lgl1 was decreased in CDH + TO. CONCLUSION: TO reversed pulmonary hypoplasia and stimulated early Wnt signaling in CDH fetal rabbits. TYPE OF STUDY: Basic science, prospective. LEVEL OF EVIDENCE: II.

Robotic-assisted, spleen-preserving distal pancreatectomy for a solid pseudopapillary tumour in a pediatric patient: a case report and review of the literature.

Solid pseudopapillary tumour is a rare carcinoma of the pancreas with low-grade malignant potential that typically presents in females in their third decade. The tumour most commonly occurs in the tail of the pancreas, although any site can be affected. Surgical resection is the standard treatment and offers an excellent prognosis. Robotic-assisted laparoscopic surgery is an emerging technique for the treatment of pancreatic neoplasms. We report a case of a 17-year-old female with acute onset abdominal pain who was found to have a mass in the distal pancreas. A robotic-assisted laparoscopic distal pancreatectomy with spleen preservation was successfully performed, its first reported use in a pediatric patient. The patient had an uncomplicated recovery. The robotic approach can be considered for younger patients presenting with a solid pseudopapillary tumour in the distal pancreas.

A simulated training model for laparoscopic pyloromyotomy: Is 3D printing the way of the future?

BACKGROUND: Hypertrophic pyloric stenosis (HPS) is a common neonatal condition treated with open or laparoscopic pyloromyotomy. 3D-printed organs offer realistic simulations to practice surgical techniques. The purpose of this study was to validate a 3D HPS stomach model and assess model reliability and surgical realism. METHODS: Medical students, general surgery residents, and adult and pediatric general surgeons were recruited from a single center. Participants were videotaped three times performing a laparoscopic pyloromyotomy using box trainers and 3D-printed stomachs. Attempts were graded independently by three reviewers using GOALS and Task Specific Assessments (TSA). Participants were surveyed using the Index of Agreement of Assertions on Model Accuracy (IAAMA). RESULTS: Participants reported their experience levels as novice (22%), inexperienced (26%), intermediate (19%), and experienced (33%). Interrater reliability was similar for overall average GOALS and TSA scores. There was a significant improvement in GOALS (p<0.0001) and TSA scores (p=0.03) between attempts and overall. Participants felt the model accurately simulated a laparoscopic pyloromyotomy (82%) and would be a useful tool for beginners (100%). CONCLUSION: A 3D-printed stomach model for simulated laparoscopic pyloromyotomy is a useful training tool for learners to improve laparoscopic skills. The GOALS and TSA provide reliable technical skills assessments. LEVEL OF EVIDENCE: II.

Does size matter? Correlation of ultrasound findings in children without clinical evidence of acute appendicitis.

PURPOSE: The purpose of this study was to determine whether children with a positive ultrasound (US) for acute appendicitis but a negative clinical picture developed appendicitis requiring definitive management. METHODS: After obtaining IRB approval, we conducted a retrospective review of patients ≤17years who presented with possible acute appendicitis between April 1st, 2014, and December 31st, 2015. We included patients with a US suggestive of acute appendicitis based on size criteria but without concerning clinical features. Patients were discharged from the emergency department (ED) or admitted for observation. Variables included demographic data, US characteristics, clinical findings, length of follow-up, and appendectomy. RESULTS: Of the 31 patients identified, 45% were male and average age was 11.3yrs. On US, the average maximal diameter of the appendix was 6.93mm. The median length of follow-up was 16.8 months, including 10 returns to the ED by 9 patients. Three of these underwent immediate laparoscopic appendectomy, while one had interval appendectomy. There were no cases of perforated appendicitis, and only 2 cases demonstrated pathology consistent with appendicitis. CONCLUSION: These findings demonstrate that it is safe to consider conservative measures such as observation or discharge in children with a positive US for appendicitis based on size criteria but a negative clinical picture. LEVEL OF EVIDENCE: 4.