General surgery applicant perspectives: Two years of virtual interview experiences and supplemental application impressions

BACKGROUND

We sought to evaluate the unique benefits and challenges the virtual recruitment and interviewing platform had on general surgery residency applicants.

METHODS

Applicants who interviewed for a categorical position at our institution during the 2021 and 2022 Match season were contacted to participate in the anonymous online survey focused on applicant behavior related to the virtual interview format. Data were analyzed using chi-square and paired t-tests.

RESULTS

A response rate of 56.7 ​% (n ​= ​135) was achieved. Applicants accepted a median of 17 (IQR 13-20) interviews in 2021 and 15 (IQR 11-19) interviews in 2022. More than half (54 ​%) of applicants indicated they applied to more programs, and 53 ​% accepted more interviews, because of the virtual format. The greatest advantages of the virtual interviews as cited by applicants were saving money (96.3 ​%), saving time (49.6 ​%), and avoiding travel risks (43.7 ​%). The top limitations of virtual interviews were less exposure to current residents and faculty (61.5 ​%), to the city or location of the program (58.5 ​%), and difficultly comparing programs (57.8 ​%). The 2022 Match cycle included use of the supplemental application; however, 85 ​% of applicants did not feel that the supplemental improved their overall application. Some applicants (20 ​%) who "signaled" programs did not receive an interview offer from any of the programs they signaled.

CONCLUSION

The transition to virtual interviews saved applicants time and money but limited their exposure. Future efforts to maintain virtual interviews will need to be balanced against the intangible benefit of human interaction and observing a program's culture.

Prevalence and Outcomes of High versus Low Ratio Plasma to Red Blood Cell Resuscitation in a Multi-Institutional Cohort of Severely Injured Children

BACKGROUND

The benefit of targeting high ratio fresh frozen plasma (FFP):red blood cell (RBC) transfusion in pediatric trauma resuscitation is unclear as existing studies are limited to patients who retrospectively met criteria for massive transfusion. The purpose of this study is to evaluate the use of high ratio FFP:RBC transfusion and the association with outcomes in children presenting in shock.

METHODS

A post-hoc analysis of a 24-institution prospective observational study (4/2018-9/2019) of injured children <18 years with elevated age-adjusted shock index was performed. Patients transfused within 24 hours were stratified into cohorts of low (<1:2) or high (>1:2) ratio FFP:RBC. Nonparametric Kruskal-Wallis and chi-square were used to compare characteristics and mortality. Competing risks analysis was used to compare extended (≥75th percentile) ventilator, intensive care, and hospital days while accounting for early deaths.

RESULTS

Of 135 children with median (IQR) age 10 (5,14) years and weight 40 (20,64) kg, 85 (63%) received low ratio transfusion and 50 (37%) high ratio despite similar activation of institutional massive transfusion protocols (MTP; low-38%, high-46%, p = .34). Most patients sustained blunt injuries (70%). Median injury severity score was greater in high ratio patients (low-25, high-33, p = .01); however, hospital mortality was similar (low-24%, high-20%, p = .65) as was the risk of extended ventilator, ICU, and hospital days (all p > .05).

CONCLUSION

Despite increased injury severity, patients who received a high ratio of FFP:RBC had comparable rates of mortality. These data suggest high ratio FFP:RBC resuscitation is not associated with worst outcomes in children who present in shock. MTP activation was not associated with receipt of high ratio transfusion, suggesting variability in MTP between centers.

LEVEL OF EVIDENCE

Prospective cohort study, Level II.

Behavioral Health Screening and Follow-Up Services in Pediatric Trauma Centers Across the United States

OBJECTIVE

Over 120,000 U.S. children are hospitalized for traumatic injury annually, a major risk factor for behavioral health problems such as acute/posttraumatic stress disorder (PTSD) and depression. Pediatric trauma centers (PTCs) are well positioned to address the recent mandate by the American College of Surgeons Committee on Trauma to screen and refer for behavioral health symptoms. However, most PTCs do not provide screening or intervention, or use varying approaches. The objective of this mixed-methods study was to assess PTCs' availability of behavioral health resources and identify barriers and facilitators to service implementation following pediatric traumatic injury (PTI).

METHODS

Survey data were collected from 83 Level I (75%) and Level II (25%) PTC program managers and coordinators across 36 states. Semistructured, qualitative interviews with participants (N = 24) assessed the feasibility of implementing behavioral health education, screening, and treatment for PTI patients and caregivers.

RESULTS

Roughly half of centers provide behavioral health screening, predominantly administered by nurses for acute stress/PTSD. Themes from qualitative interviews suggest that (1) service provision varies by behavioral health condition, resource, delivery method, and provider; (2) centers are enthusiastic about service implementation including screening, inpatient brief interventions, and follow-up assessment; but (3) require training and lack staff, time, and funding to implement services.

CONCLUSIONS

Sustainable, scalable, evidence-based service models are needed to assess behavioral health symptoms after PTI. Leadership investment is needed for successful implementation. Technology-enhanced, stepped-care approaches seem feasible and acceptable to PTCs to ensure the availability of personalized care while addressing barriers to sustainability.

Crystalloid volume is associated with short-term morbidity in children with severe traumatic brain injury: An Eastern Association for the Surgery of Trauma multicenter trial post hoc analysis

OBJECTIVE

This study examined differences in clinical and resuscitation characteristics between injured children with and without severe traumatic brain injury (sTBI) and aimed to identify resuscitation characteristics associated with improved outcomes following sTBI.

METHODS

This is a post hoc analysis of a prospective observational study of injured children younger than 18 years (2018-2019) transported from the scene, with elevated shock index pediatric-adjusted on arrival and head Abbreviated Injury Scale score of ≥3. Timing and volume of resuscitation products were assessed using χ 2t test, Fisher's exact t test, Kruskal-Wallis, and multivariable logistic regression analyses.

RESULTS

There were 142 patients with sTBI and 547 with non-sTBI injuries. Severe traumatic brain injury patients had lower initial hemoglobin (11.3 vs. 12.4, p < 0.001), greater initial international normalized ratio (1.4 vs. 1.1, p < 0.001), greater Injury Severity Score (25 vs. 5, p < 0.001), greater rates of ventilator (59% vs. 11%, p < 0.001) and intensive care unit (ICU) requirement (79% vs. 27%, p < 0.001), and more inpatient complications (18% vs. 3.3%, p < 0.001). Severe traumatic brain injury patients received more prehospital crystalloid (25% vs. 15%, p = 0.008), ≥1 crystalloid boluses (52% vs. 24%, p < 0.001), and blood transfusion (44% vs. 12%, p < 0.001) than non-sTBI patients. Among sTBI patients, receipt of ≥1 crystalloid bolus (n = 75) was associated with greater ICU need (92% vs. 64%, p < 0.001), longer median ICU (6 vs. 4 days, p = 0.027) and hospital stay (9 vs. 4 days, p < 0.001), and more in-hospital complications (31% vs. 7.5%, p = 0.003) than those who received <1 bolus (n = 67). These findings persisted after adjustment for Injury Severity Score (odds ratio, 3.4-4.4; all p < 0.010).

CONCLUSION

Pediatric trauma patients with sTBI received more crystalloid than those without sTBI despite having a greater international normalized ratio at presentation and more frequently requiring blood products. Excessive crystalloid may be associated with worsened outcomes, including in-hospital mortality, seen among pediatric sTBI patients who received ≥1 crystalloid bolus. Further attention to a crystalloid sparing, early transfusion approach to resuscitation of children with sTBI is needed.

LEVEL OF EVIDENCE

Therapeutic/Care Management; Level IV.

Multicenter Assessment of Cryoanalgesia Use in Minimally Invasive Repair of Pectus Excavatum: A 20-center Retrospective Cohort Study

OBJECTIVE

To assess the clinical implications of cryoanalgesia for pain management in children undergoing minimally invasive repair of pectus excavatum (MIRPE).

BACKGROUND

MIRPE entails significant pain management challenges, often requiring high postoperative opioid use. Cryoanalgesia, which blocks pain signals by temporarily ablating intercostal nerves, has been recently utilized as an analgesic adjunct. We hypothesized that the use of cryoanalgesia during MIRPE would decrease postoperative opioid use and length of stay (LOS).

MATERIALS AND METHODS

A multicenter retrospective cohort study of 20 US children's hospitals was conducted of children (age below 18 years) undergoing MIRPE from January 1, 2014, to August 1, 2019. Differences in total postoperative, inpatient, oral morphine equivalents per kilogram, and 30-day LOS between patients who received cryoanalgesia versus those who did not were assessed using bivariate and multivariable analysis. P value <0.05 is considered significant.

RESULTS

Of 898 patients, 136 (15%) received cryoanalgesia. Groups were similar by age, sex, body mass index, comorbidities, and Haller index. Receipt of cryoanalgesia was associated with lower oral morphine equivalents per kilogram (risk ratio=0.43, 95% confidence interval: 0.33-0.57) and a shorter LOS (risk ratio=0.66, 95% confidence interval: 0.50-0.87). Complications were similar between groups (29.8% vs 22.1, P =0.07), including a similar rate of emergency department visit, readmission, and/or reoperation.

CONCLUSIONS

Use of cryoanalgesia during MIRPE appears to be effective in lowering postoperative opioid requirements and LOS without increasing complication rates. With the exception of preoperative gabapentin, other adjuncts appear to increase and/or be ineffective at reducing opioid utilization. Cryoanalgesia should be considered for patients undergoing this surgery.

General surgery applicants report the impact of virtual interviews on their rank list and match

Purpose

The transition to an all-virtual application cycle for General Surgery Match 2021 significantly altered interview day and the interactions of applicants with residency programs. We sought to evaluate the impact of a virtual match cycle on applicants' rank list and Match results.

Methods

We surveyed applicants who were offered an interview for a categorical general surgery residency position at our institution during the 2021 match season. Voluntary anonymous surveys were sent after the rank list deadline and again after the Match.

Results

Out of 108 interviewees, 43 completed the survey (40%). Median age was 26, and 61% of respondents were male and 82% white, which skewed from our diverse interview pool. They completed a median of 17 interviews. 69% felt they had sufficient exposure to make their rank list, and this group reached statistically significant higher confidence in their decisions when compared with those who endorsed not having enough exposure to the residency programs (58% vs 42%, p = 0.02). Applicants cited the most influential interview day factors to be their interview with faculty and the virtual social with residents. Least important was their ability to assess the hospital facility. Among seven different program factors, comradery between faculty and residents (31%) and perceived happiness of the residents (18.6%) were most often selected most influential. Only 56% reported ranking all programs at which they interviewed. After submitting their rank list, 59% of applicants stated they had not visited the city of their top ranked program; however, post-match surveys revealed only 44% matched to a program in a city unknown to them. 57% of applicants stated they reached out to their top choice program with additional questions, but only 47% matched at one of those institutions.

Conclusions

Even in the constraints of the virtual interviews, most applicants felt they had sufficient exposure to programs to make their rank list. Applicants were willing to highly rank cities they had never visited and to reach out to programs but were ultimately less successful matching at those programs. Understanding what factors and communications most impact applicants and programs may lead to a more successful Match.

Supplementary Information

The online version contains supplementary material available at 10.1007/s44186-022-00071-8.

Assessing service quality and access in trauma centers through behavioral health screening, education, and treatment after pediatric injury

BACKGROUND

Over 120,000 U.S. children are hospitalized annually for traumatic injury, with approximately 20% developing acute stress disorder (ASD), posttraumatic stress disorder (PTSD), or depression. The ACS COT recommends that trauma centers address emotional recovery after injury; however, few pediatric trauma centers (PTCs) assess behavioral health symptoms. This study describes results from a survey with PTC providers assessing the landscape of behavioral health screening, education, and treatment.

METHODS

Trauma program leaders from 83 US Level I and II trauma centers across 36 states completed a survey assessing center characteristics and decision-making, availability, and perceptions of behavioral health resources.

RESULTS

Nearly half (46%) of centers provide behavioral health screens for pediatric patients, and 18% screen family members, with screens mostly conducted by nurses or social workers for ASD or PTSD. Two-thirds provide child behavioral health education and 47% provide education to caregivers/family. Two-thirds provide treatment connections, typically via referrals or outpatient clinics. Behavioral health screening, education, and treatment connections were rated as very important (M > 8.5/10), with higher ratings for the importance of screening children versus caregivers. Child maltreatment (59%), observed patient distress (53%), child substance use (52%), injury mechanism (42%) and severity (42%) were prioritized in screening decision-making.

CONCLUSION

Service provision varies by method, resource, and provider, highlighting the lack of a roadmap for centers to provide behavioral health services. Adoption of universal education and screening procedures in PTCs is crucial to increase access to services for injured children and caregivers. PTCs are well-positioned to offer these services.

LEVEL OF EVIDENCE

Level II.

Caregivers' and Young Children's Emotional Health Needs After Pediatric Traumatic Injury

Pediatric traumatic injury (PTI) is associated with emotional health difficulties, but most US trauma centers do not adequately address emotional recovery needs. This study aimed to assess families' emotional health needs following PTI and determine how technology could be used to inform early interventions. Individual semi-structured, qualitative interviews were conducted with caregivers of children admitted to a Level I trauma center in the Southeastern United States to understand families' experiences in-hospital and post-discharge. Participants included 20 caregivers of PTI patients under age 12 (M = 6.4 years; 70% male, 45% motor vehicle collision). Thematic analysis was used to analyze data from interviews that were conducted until saturation. Caregivers reported varying emotional needs in hospital and difficulties adjusting after discharge. Families responded enthusiastically to the potential of a technology-enhanced resource for families affected by PTI. A cost-effective, scalable intervention is needed to promote recovery and has potential for widespread pediatric hospital uptake.

Predictability and stability testing to assess clinical decision instrument performance for children after blunt torso trauma

OBJECTIVE

The Pediatric Emergency Care Applied Research Network (PECARN) has developed a clinical-decision instrument (CDI) to identify children at very low risk of intra-abdominal injury. However, the CDI has not been externally validated. We sought to vet the PECARN CDI with the Predictability Computability Stability (PCS) data science framework, potentially increasing its chance of a successful external validation.

MATERIALS & METHODS

We performed a secondary analysis of two prospectively collected datasets: PECARN (12,044 children from 20 emergency departments) and an independent external validation dataset from the Pediatric Surgical Research Collaborative (PedSRC; 2,188 children from 14 emergency departments). We used PCS to reanalyze the original PECARN CDI along with new interpretable PCS CDIs developed using the PECARN dataset. External validation was then measured on the PedSRC dataset.

RESULTS

Three predictor variables (abdominal wall trauma, Glasgow Coma Scale Score <14, and abdominal tenderness) were found to be stable. A CDI using only these three variables would achieve lower sensitivity than the original PECARN CDI with seven variables on internal PECARN validation but achieve the same performance on external PedSRC validation (sensitivity 96.8% and specificity 44%). Using only these variables, we developed a PCS CDI which had a lower sensitivity than the original PECARN CDI on internal PECARN validation but performed the same on external PedSRC validation (sensitivity 96.8% and specificity 44%).

CONCLUSION

The PCS data science framework vetted the PECARN CDI and its constituent predictor variables prior to external validation. We found that the 3 stable predictor variables represented all of the PECARN CDI's predictive performance on independent external validation. The PCS framework offers a less resource-intensive method than prospective validation to vet CDIs before external validation. We also found that the PECARN CDI will generalize well to new populations and should be prospectively externally validated. The PCS framework offers a potential strategy to increase the chance of a successful (costly) prospective validation.

Characteristics and predictors of intensive care unit admission in pediatric blunt abdominal trauma

BACKGROUND

Pediatric trauma patients sustaining blunt abdominal trauma (BAT) with intra-abdominal injury (IAI) are frequently admitted to the intensive care unit (ICU). This study was performed to identify predictors for ICU admission following BAT.

METHODS

Prospective study of children (< 16 years) who presented to 14 Level-One Pediatric Trauma Centers following BAT over a 1-year period. Patients were categorized as ICU or non-ICU patients. Data collected included vitals, physical exam findings, laboratory results, imaging, and traumatic injuries. A multivariable hierarchical logistic regression model was used to identify predictors of ICU admission. Predictive ability of the model was assessed via tenfold cross-validated area under the receiver operating characteristic curves (cvAUC).

RESULTS

Included were 2,182 children with 21% (n = 463) admitted to the ICU. On univariate analysis, ICU patients were associated with abnormal age-adjusted shock index, increased injury severity scores (ISS), lower Glasgow coma scores (GCS), traumatic brain injury (TBI), and severe solid organ injury (SOI). With multivariable logistic regression, factors associated with ICU admission were severe trauma (ISS > 15), anemia (hematocrit < 30), severe TBI (GCS < 8), cervical spine injury, skull fracture, and severe solid organ injury. The cvAUC for the multivariable model was 0.91 (95% CI 0.88-0.92).

CONCLUSION

Severe solid organ injury and traumatic brain injury, in association with multisystem trauma, appear to drive ICU admission in pediatric patients with BAT. These results may inform the design of a trauma bay prediction rule to assist in optimizing ICU resource utilization after BAT.

STUDY DESIGN

Prognosis study.

LEVEL OF EVIDENCE: 1

Hospital-based intervention is rarely needed for children with low-grade blunt abdominal solid organ injury: An analysis of the Trauma Quality Improvement Program registry

BACKGROUND

Children with low-grade blunt solid organ injury (SOI) have historically been admitted to an inpatient setting for monitoring, but the evidence supporting the necessity of this practice is lacking. The purpose of this study was to quantify the frequency and timing of intervention for hemorrhage and to describe hospital-based resource utilization for low-grade SOI in the absence of other major injuries (OMIs).

METHODS

A cohort of children (aged <16 years) with blunt American Association for the Surgery of Trauma grade 1 or 2 SOI from the American College of Surgeons Trauma Quality Improvement Program registry (2007-2017) was analyzed. Children were excluded if they had confounding factors associated with intervention for hemorrhage (comorbidities, OMIs, or extra-abdominal surgical procedures). Outcomes included frequency and timing of intervention (laparotomy, angiography, or transfusion) for hemorrhage, as well as hospital-based resource utilization.

RESULTS

A total of 1,019 children were identified with low-grade blunt SOI and no OMIs. Nine hundred eighty-six (96.8%) of these children were admitted to an inpatient unit. Admitted children with low-grade SOI had a median length-of-stay of 2 days and a 23.9% intensive care unit admission rate. Only 1.7% (n = 17) of patients with low-grade SOI underwent an intervention, with the median time to intervention being the first hospital day. No child who underwent angiography was transfused or had an abnormal initial ED shock index.

CONCLUSION

Children with low-grade SOI are routinely admitted to the hospital and often to the intensive care unit but rarely undergo hospital-based intervention. The most common intervention was angiography, with questionable indications in this cohort. These data question the need for inpatient admission for low-grade SOI and suggest that discharge from the emergency room may be safe. Prospective investigation into granular risk factors to identify the rare patient needing hospital-based intervention is needed, as is validation of the safety of ambulatory management.

LEVEL OF EVIDENCE

Prognostic and epidemiological, level III.

Long-term outcomes of pediatric laparoscopic needled-assisted inguinal hernia repair: A 10-year experience

PURPOSE

Laparoscopic inguinal hernia repair (LIHR) has gained wide acceptance over the past decade, although studies with longer term follow-up are lacking. We present one of the largest cohorts of children undergoing laparoscopic needle-assisted repair (LNAR) with long-term follow-up.

METHODS

A clinical quality database was maintained for children ≤14 years of age who underwent laparoscopic needle-assisted repair between 2009 and 2017 with review of follow-up through 2019. De-identified data was reviewed.

RESULTS

1023 patients with 1457 LNAR were included during the 10-year period. Mean age at surgery was 2.56 years (2 days to14 years). The overall hernia recurrence rate was 0.75% (11/1457). A total of four postoperative hydroceles required intervention. Preterm infant repair done <60w post conceptional age had a significantly lower recurrence rate (0.63%) than other patients (0.82%) (p < 0.01). 64.2% of patients had clinical follow-up over a period of 11 years with a mean follow-up of 5.97 years.

CONCLUSION

We present a large cohort study of consecutive pediatric laparoscopic hernia repairs followed over an 11-year period. LNAR is safe and effective for term and preterm patients with similar complication rates to other techniques, including open repair. Additionally, our results suggest that preterm infants may have superior outcomes with this method.

LEVEL OF EVIDENCE

Level III - Retrospective Comparative Study.

Resident-Driven Wellness Initiatives Improve Resident Wellness and Perception of Work Environment

BACKGROUND

Resident burnout is associated with increased adverse patient events and increased incidence of resident depression and suicide when compared to the general population. We hypothesized that resident-driven assessment and implementation of wellness measures would allow implementation of desired interventions and facilitate improvement in wellness.

METHODS

A wellness intervention team was established to address resident wellness and job satisfaction. A needs assessment to determine desired interventions as well as a three-part anonymous 5-point Likert scale survey was developed and distributed to general surgery residents. Following implementation of three measures, a postintervention survey was administered at 6 and 15 mo to the same cohort. Analysis of variance test was used to evaluate for significant difference between preintervention and postintervention surveys.

RESULTS

Three interventions were implemented: two protected weekday personal days per year, modernization of resident workspace, and additional meal funds. There were statistically significant changes in perceptions of wellness opportunities (3.14 versus 3.88 and 3.7; P < 0.05), time for wellness (2.53 versus 3.42 and 3.2; P < 0.05), work/life balance satisfaction (2.86 versus 3.71 and 3.41; P < 0.05), and improved quality of life (2.67 versus 3.3 and 3.0; P < 0.05) in both 6-mo and 15-mo postintervention responses.

CONCLUSIONS

Implementation of resident-selected wellness measures was found to influence overall resident satisfaction and improved perception of the working environment. Several scores of wellness items showed sustained improvement at 15 mo. These results suggest that resident-driven wellness interventions can positively affect working conditions for residents.

Trauma Resilience and Recovery Program: Addressing Mental Health in Pediatric Trauma Centers

OBJECTIVE

Approximately 225,000 children sustain injuries requiring hospitalization annually. Posttraumatic stress disorder (PTSD) and depression are prevalent among pediatric patients and caregivers post-injury. Most U.S. trauma centers do not address patients' mental health needs. Better models of care are needed to address emotional recovery. This article describes the engagement and recovery trajectories of pediatric patients enrolled in the Trauma Resilience and Recovery Program (TRRP), a stepped-care model to accelerate emotional recovery following hospitalization.

METHODS

TRRP is designed to (a) provide in-hospital education about post-injury emotional recovery and assess child and caregiver distress; (b) track mental health symptoms via a 30-day text-messaging program; (c) complete 30-day PTSD and depression phone screens; and (d) provide evidence-based treatment via telehealth or in-person services or referrals, if needed. All 154 families approached were offered TRRP services, 96% of whom agreed to enroll in TRRP. Most patients were boys (59.8%), and average age was 9.12 years [standard deviation (SD) = 5.42]. Most injuries (45.8%) were sustained from motor vehicle accidents.

RESULTS

In hospital, 68.5% of caregivers and 78.3% of children reported clinically significant distress levels. Over 60% of families enrolled in the texting service. TRRP re-engaged 40.1% of families for the 30-day screen, 35.5% of whom reported clinically significant PTSD (M = 13.90, SD = 11.42) and/or depression (M = 13.35, SD = 11.16). Most (76%) patients with clinically significant symptomology agreed to treatment.

CONCLUSIONS

Our intervention model was feasible and increased reach to families who needed services. Efforts to improve follow-up engagement are discussed, as are initial successes in implementing this model in other pediatric trauma centers.

Variability in the evalution of pediatric blunt abdominal trauma

PURPOSE

To describe the practice pattern for routine laboratory and imaging assessment of children following blunt abdominal trauma (BAT).

METHODS

Children (age < 16 years) presenting to 14 pediatric trauma centers following BAT over a 1-year period were prospectively identified. Injury, demographic, routine laboratory and imaging utilization data were collected. Descriptive, comparative, and correlation analysis was performed.

RESULTS

2188 children with a median age of 8 (4,12) years were included and the median injury severity score was 5 (1,10). There were significant differences in activation status, injury severity, and mechanism across centers; however, there was no correlation of level of activation, injury severity, or severe mechanism with test utilization. Routine laboratory and imaging utilization for hematocrit, hepatic enzymes, pancreatic enzymes, base deficit urine microscopy, chest and pelvis X-ray, and abdominal computed tomography (CT) varied significantly among centers. Only obtaining a hematocrit had a moderate correlation with CT use. There was no correlation between centers that were high or low frequency laboratory utilizers with CT use.

CONCLUSIONS

Wide variability exists in the routine initial laboratory and imaging assessment in children following BAT. This represents an opportunity for quality improvement in pediatric trauma.

LEVEL OF EVIDENCE

Level II.

What Happened to the Complication? The Importance of ACS NSQIP Pediatric in Optimizing Quality Improvement Initiatives for Resident Education

OBJECTIVE

Morbidity and Mortality (M&M) conference is considered the golden hour of surgical education. Most training programs lack standardized methods to evaluate self-reported outcomes and contributions to resident education. The purpose of this study was to determine whether residents underreport pediatric postoperative complications thereby limiting a comprehensive educational opportunity and the ability to adequately perform quality improvement during M&M conference.

DESIGN

A retrospective analysis of resident reports submitted to the M&M committee at an academic medical center was conducted over 1 year. All complications were compared to the American College of Surgeons (ACS) Pediatric National Surgical Quality Improvement Program (NSQIP) data abstracted over the same period. A descriptive analysis of perioperative events was performed.

SETTING

This study was conducted at the Medical University of South Carolina Medical Center and MUSC Children's Hospital, an academic tertiary care center located in Charleston, South Carolina.

RESULTS

Overall, 81 complications were captured. Resident and NSQIP databases captured 27 (33%) and 68 (84%) complications, respectively. Residents were more likely to report major complications. More common sources of postoperative morbidity, including surgical site infection and transfusion, were underreported at 20% and 5%, respectively.

CONCLUSIONS

Resident reporting inadequately captures the full complement of pediatric perioperative complications. NSQIP-abstracted data serve as a useful adjunct to traditional M&M reporting in capturing complications underreported by trainees.

A multicenter, pediatric quality improvement initiative improves surgical wound class assignment, but is it enough?

BACKGROUND/PURPOSE

Surgical wound classification (SWC) is widely utilized for surgical site infection (SSI) risk stratification and hospital comparisons. We previously demonstrated that nearly half of common pediatric operations are incorrectly classified in eleven hospitals. We aimed to improve multicenter, intraoperative SWC assignment through targeted quality improvement (QI) interventions.

METHODS

A before-and-after study from 2011-2014 at eleven children's hospitals was conducted. The SWC recorded in the hospital's intraoperative record (hospital-based SWC) was compared to the SWC assigned by a surgeon reviewer utilizing a standardized algorithm. Study centers independently performed QI interventions. Agreement between the hospital-based and surgeon SWC was analyzed with Cohen's weighted kappa and chi square.

RESULTS

Surgeons reviewed 2034 cases from 2011 (Period 1) and 1998 cases from 2013 (Period 2). Overall SWC agreement improved from 56% to 76% (p<0.01) and weighted kappa from 0.45 (95% CI 0.42-0.48) to 0.73 (95% CI 0.70-0.75). Median (range) improvement per institution was 23% (7-35%). A dose-response-like pattern was found between the number of interventions implemented and the amount of improvement in SWC agreement at each institution.

CONCLUSIONS

Intraoperative SWC assignment significantly improved after resource-intensive, multifaceted interventions. However, inaccurate wound classification still commonly occurred. SWC used in SSI risk-stratification models for hospital comparisons should be carefully evaluated.

Use of real-time ultrasound during central venous catheter placement: Results of an APSA survey

PURPOSE

The purpose of this study was to document the attitudes and practice patterns of pediatric surgeons regarding use of RTUS with CVC placement.

METHODS

An analytic survey composed of 20 questions was sent via APSA headquarters to all practicing members. Answers were summarized as frequency and percentage. Distributions of answers were compared using the chi-square tests. P-values ≤0.05 were considered statistically significant.

RESULTS

361 of 1072 members chose to participate for a response rate of 34%. Most placed CVCs into the subclavian veins (SCV) of patients without coagulopathy, with the left SCV chosen approximately four times more often than the right. Conversely, RTUS use at the internal jugular vein (IJV) was significantly greater than that for the SCV (p<0.001). Coagulopathy, multiple previous catheters, and morbid obesity were identified as patient characteristics that would encourage RTUS use. The most commonly cited potential barriers to RTUS use were lack of formal ultrasound training and the belief that ultrasound is not necessary.

CONCLUSIONS

Variability exists among pediatric surgeons regarding use of RTUS during CVC placement. Additional studies are needed to document actual frequency of use, how RTUS is implemented, and its efficacy of preventing adverse events in children.

Venous thromboembolism prophylaxis in the pediatric trauma population

BACKGROUND/PURPOSE

The aim of this study was to review evidence-based literature addressing pertinent questions about venous thromboembolism (VTE) after traumatic injury in children.

METHODS

Data were obtained from English-language articles identified through Pubmed published from 1995 until November 2012, and from bibliographies of relevant articles. Studies were included if they contributed evidence to one of the following questions. In the pediatric traumatic injury population: (1) What is the overall incidence of VTE? (2) Is age (adolescence versus pre-adolescence) associated with higher VTE incidence? (3) Which risk factors are associated with higher VTE incidence? (4) Does mechanical and/or pharmacological prophylaxis impact outcomes?

RESULTS

Eighteen articles were included in this systematic review. The evidence regarding each question was evaluated, graded by author consensus, and summarized.

CONCLUSIONS

The overall incidence of VTE is low. Older (>13years) and more severely injured patients are at higher VTE risk. Additional factors including injury type or presence of a central venous catheter also place a patient at higher VTE risk. Implementation of a risk-based clinical practice guideline for VTE prophylaxis has been associated with reduced symptomatic VTE at one institution. Randomized, prospective trials analyzing outcomes of VTE prophylaxis in pediatric trauma victims are needed.

Effectiveness of Biobrane for treatment of partial-thickness burns in children

PURPOSE

Wound care for partial-thickness burns should alleviate pain, decrease hospital length of stay, and be readily applied to a variety of wounds. The effectiveness of Biobrane (UDL Laboratories, Rockford, IL) is compared with that of Beta Glucan Collagen (BGC; Brennan Medical, St. Paul, MN) in a retrospective cohort study.

METHODS

A retrospective chart review of all children treated at a tertiary care pediatric hospital between 2003 and 2009 identified patients with partial-thickness burns treated with Biobrane. These patients were compared with historical controls treated with BGC.

RESULTS

A total of 235 children between the ages of 4 weeks and 18 years with an average of 6.0% body surface area partial-thickness burns were treated with Biobrane. In a multivariate statistical analysis, patients treated with Biobrane healed significantly faster than those treated with BGC (Biobrane vs BGC: median, 9 vs 13 days; P = .019; hazard ratio, 1.68). In addition, patients who required inpatient treatment trended toward having shorter length of hospital stay in the Biobrane group (2.6 vs 4.1 days, P = .079).

CONCLUSION

Partial-thickness burn care consists of early debridement and application of a burn wound dressing. Biobrane dressings result in faster healing compared with BGC and may decrease hospital length of stay for patients requiring inpatient admission.

A novel automated assay for the rapid identification of metastatic breast carcinoma in sentinel lymph nodes

BACKGROUND

The authors prospectively evaluated the performance of a proprietary molecular testing platform using one-step nucleic acid amplification (OSNA) for the detection of metastatic carcinoma in sentinel lymph nodes (SLNs) in a large multicenter trial and compared the OSNA results with the results from a detailed postoperative histopathologic evaluation (reference pathology) and from intraoperative imprint cytology (IC).

METHODS

In total, 1044 SLN samples from 496 patients at 11 clinical sites were analyzed. Alternate 1-mm sections were subjected to either detailed histopathologic evaluation with hematoxylin and eosin and pancytokeratin immunostaining or the OSNA Breast Cancer System, which was calibrated to detect tumor deposits >0.2 mm by measuring cytokeratin 19 messenger RNA. At 7 sites, IC was performed before permanent section. The OSNA results were classified as negative (<250 copies/μL), micrometastases (from ≥250 to <5000 copies/μL), or macrometastases (≥5000 copies/μL).

RESULTS

The sensitivity and specificity of the OSNA breast cancer system compared with reference pathology were 77.5% (95% confidence interval, 69.7%-84.2%) and 95.8% (95% confidence interval, 94.3%-97.0%), respectively, before discordant case analyses (DCA). Sensitivity and specificity after DCA were 82.7% and 97.7%, and final concordance was 95.8%. Performance for invasive lobular carcinoma demonstrated 88.2% sensitivity (95% confidence interval, 63.6%-98.5%) and 98.5% specificity (95% confidence interval, 92%-100%). The sensitivity of OSNA was significantly better than that of IC (80% vs 63%; P = .0229).

CONCLUSIONS

The OSNA breast cancer system proved to be highly accurate for the detection of metastatic breast cancer in axillary SLNs. Sensitivity was comparable to that predicted for conventional postoperative histologic examination at 2-mm intervals and was significantly more sensitive than IC. Automation, semiquantitative results enabling the differentiation of macrometastasis and micrometastasis, and rapid results render the assay suitable for intraoperative and/or permanent evaluation of SLNs.

Anti-N-methyl-D-aspartate receptor encephalitis associated with an ovarian teratoma in an adolescent female

Anti-N-methyl-d-aspartate (NMDA) receptor encephalitis is a recently described paraneoplastic syndrome with prominent neuropsychiatric symptoms. We report a case of NMDA receptor encephalitis in a 15-year-old female related to the development of NMDA receptor autoantibodies triggered by an ovarian teratoma. Removal of the mature teratoma proved curative with eventual resolution of the paraneoplastic disease process and associated psychiatric symptoms. Increasingly, reports of anti-NMDA receptor encephalitis associated with ovarian teratomas in pediatric patients, as well as a novel assay to measure these antibodies, suggest an etiology for this disease process that may be amenable to prompt surgical excision. The clinical presentation, diagnosis, and surgical management of the disease, as well as a review of the literature, are included.

NF-kappaB activation mediates resistance to IFN beta in MLL-rearranged acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) harboring the t(4;11) translocation is associated with a very poor prognosis; innovative treatment strategies are required to improve the current 5-year survival rate of 30-40%. Interferon beta (IFN beta) has shown promise in the treatment of both solid and hematologic malignancies, although the short half-life and toxicity associated with high doses have limited its clinical utility. To overcome these limitations, we investigated the effect of continuous, gene transfer-mediated delivery of IFN beta using adeno-associated virus (AAV)-mediated expression, on ALL cells with the t(4;11) translocation. We found that this method of IFN beta delivery resulted in complete remission of leukemia in a murine model. However, leukemic cells eventually became resistant to IFN beta and relapse was observed. Activation of NF-kappaB was identified as a mechanism for IFN beta resistance, and inhibition of NF-kappaB activity in resistant cells sensitized cells to IFN beta. IFN beta combined with agents that inhibit NF-kappaB could have therapeutic potential in the treatment of children with mixed lineage leukemia subtype ALL.

Avoiding misdiagnosing neuroblastoma as Wilms tumor

PURPOSE

Although occasionally difficult, distinguishing abdominal neuroblastoma (NBL) from Wilms tumor (WT) at presentation is important, as surgical management differs significantly. We reviewed our 20-year experience (1987-2006) treating patients with NBL, focusing on those with an initial diagnosis of WT, to determine presenting features that would have suggested the correct preoperative diagnosis.

METHODS

Retrospective case cohort study reviewing charts and imaging of patients with NBL initially diagnosed clinically with WT. Preoperative symptoms, laboratory studies, and imaging were evaluated. Similar variables were assessed in the 20 patients with WT most recently treated at our institution.

RESULTS

Nine patients with NBL were identified as those who had an exploratory laparotomy with a preoperative diagnosis of WT; 8 underwent nephrectomy at exploration. Children with NBL had symptoms such as fever and weight loss at presentation (67%) more often than patients with WT (20%). Preoperative computed tomography demonstrated intratumoral calcifications, vascular encasement, or both in 78% of patients with NBL but were never seen in WT patients. Of interest, preoperative urinary catecholamines were elevated in 5 patients ultimately diagnosed with NBL.

CONCLUSION

Although NBL can be mistaken for WT at presentation, the presence of constitutional symptoms, or intratumoral calcification or vascular encasement on preoperative imaging should heighten suspicion for NBL. In addition, laboratory evaluation, including urinary catecholamines, should be completed before surgery when the etiology of an abdominal tumor is uncertain.

Continuous delivery of IFN-beta promotes sustained maturation of intratumoral vasculature

IFNs have pleiotropic antitumor mechanisms of action. The purpose of this study was to further investigate the effects of IFN-beta on the vasculature of human xenografts in immunodeficient mice. We found that continuous, systemic IFN-beta delivery, established with liver-targeted adeno-associated virus vectors, led to sustained morphologic and functional changes of the tumor vasculature that were consistent with vessel maturation. These changes included increased smooth muscle cell coverage of tumor vessels, improved intratumoral blood flow, and decreased vessel permeability, tumor interstitial pressure, and intratumoral hypoxia. Although these changes in the tumor vasculature resulted in more efficient tumor perfusion, further tumor growth was restricted, as the mature vasculature seemed to be unable to expand to support further tumor growth. In addition, maturation of the intratumoral vasculature resulted in increased intratumoral penetration of systemically administered chemotherapy. Finally, molecular analysis revealed increased expression by treated tumors of angiopoietin-1, a cytokine known to promote vessel stabilization. Induction of angiopoietin-1 expression in response to IFN-beta was broadly observed in different tumor lines but not in those with defects in IFN signaling. In addition, IFN-beta-mediated vascular changes were prevented when angiopoietin signaling was blocked with a decoy receptor. Thus, we have identified an alternative approach for achieving sustained vascular remodeling-continuous delivery of IFN-beta. In addition to restricting tumor growth by inhibiting further angiogenesis, maturation of the tumor vasculature also improved the efficiency of delivery of adjuvant therapy. These results have significant implications for the planning of combination anticancer therapy.

Laparoscopic repair of traumatic bowel injury in children

PURPOSE

The aim of this study was to evaluate the laparoscopic repair of isolated intestinal injuries in children who sustain focal abdominal trauma.

METHODS

A retrospective review was conducted of all patients 16 years and younger who required surgery for traumatic bowel injuries during a 5-year period at 2 university children's hospitals. The study population was composed of hemodynamically stable patients who sustained focal energy transfer to the abdomen and were diagnosed preoperatively with intestinal injury. Children sustaining multisystem injuries and gunshot wounds or who were hemodynamically unstable were excluded.

RESULTS

Fifty hemodynamically stable children were explored for preoperatively documented intestinal injury sustained after focal abdominal trauma. Laparoscopy was used to repair intracorporeally gastrointestinal injuries in 8 children. Mean operating time, time to diet, and time to discharge after laparoscopic bowel repair compared favorably with patients managed by laparotomy. An additional 6 patients had a laparoscopic-assisted bowel resection or repair after exteriorization only of the ruptured intestine through a short extension of the nearest port site. No early (missed injury, wound infection, bleeding) or late (obstruction) complications resulted after laparoscopic repair.

CONCLUSIONS

Laparoscopic primary or assisted repair of injured bowel is an appropriate surgical option in hemodynamically stable children who sustain focal abdominal trauma and may be associated with a more prompt return of intestinal function and shorter hospital stay.

Antitumor efficacy of AAV-mediated systemic delivery of interferon-beta

Type I interferons (alpha/beta) have significant antitumor activity although their short half-life and systemic side effects have limited their clinical utility. An alternative dosing schedule of continuous, low-level delivery, as is achieved by gene therapy, rather than intermittent, high concentration pulsed-dosing, might avoid the toxicity of interferon while maintaining its antitumor efficacy. We have tested a gene therapy approach in murine tumor models to treat malignancies that have shown responsiveness to interferon in clinical trials. The tumor cell lines used were moderately sensitive to the direct effects of human interferon-beta (hIFN-beta) in vitro. For in vivo testing, systemic delivery of hIFN-beta was generated following liver-targeted delivery of adeno-associated virus (AAV) vector carrying the hIFN-beta transgene. This prevented engraftment of subcutaneous human gliomas, and orthotopic, localized (intrarenal) and disseminated (primarily pulmonary) human renal cell carcinomas; and caused regression of established tumors at these sites. In a syngeneic, immunocompetent model of melanoma, AAV IFN-beta treatment limited subcutaneous tumor growth and prevented disseminated disease. A significant decrease in mean intratumoral vessel density was demonstrated in hIFN-beta-treated tumors, suggesting that in addition to a direct tumoricidal effect, the antitumor efficacy of AAV IFN-beta in this study was due to its ability to inhibit angiogenesis.

Angiogenesis inhibitors in a murine neuroblastoma model: quantitative assessment of intratumoral blood flow with contrast-enhanced gray-scale US

PURPOSE

To quantify intratumoral ultrasonographic (US) contrast agent flow at gray-scale imaging as a measure of functional tumor vascularity in an orthotopic murine neuroblastoma model treated with angiogenesis inhibitors.

MATERIALS AND METHODS

After Institutional Animal Care and Use Committee approval, retroperitoneal neuroblastomas were established in mice with unmodified NXS2 cells (n = 13) or with cells engineered to overexpress an angiogenesis inhibitor--either tissue inhibitor of matrix metalloproteinase-3 (n = 22) or a truncated soluble form of the vascular endothelial growth factor receptor-2 (truncated soluble fetal liver kinase-1; n = 13). When tumors were approximately 600 mm3, contrast material-enhanced gray-scale US was performed, and the imaging was recorded on cine clips. Regions of interest within tumors were analyzed off-line to determine postcontrast change in signal intensity (SI) from baseline to initial peak (deltaSI), rate of SI increase from baseline to initial peak (RSI), and contrast material washout. The Mann-Whitney test was used to evaluate potential differences in these US parameters between treatment groups. The mean intratumoral endothelial cell (CD34) and pericyte (smooth muscle actin [SMA]) counts at immunohistochemical analysis were also evaluated. Spearman correlation test was used to investigate the relation between US parameters and these histologic markers.

RESULTS

The deltaSI and RSI were lower in tumors overexpressing an angiogenesis inhibitor than in control tumors (all P < .03). Contrast material washout did not differ between groups. For the entire cohort, the RSI correlated with the immunohistochemical assessment of tumor vascularity (SMA and CD34 counts) (P < .003).

CONCLUSION

Quantification of intratumoral flow of a US contrast agent at gray-scale imaging shows promise for monitoring tumor vascular response to antiangiogenic therapy.

Interferon-mediated anti-angiogenic therapy for neuroblastoma

Angiogenesis appears to be a fundamental requirement for tumor growth, invasion and metastasis. Evidence also exists to suggest that inhibition of tumor-associated angiogenesis can retard tumor growth and prevent tumor spread. Several naturally occurring angiogenesis inhibitors have been identified, including type I interferons (alpha/beta). These proteins are potent inhibitors of angiogenesis and may also have direct anti-tumor and immunomodulatory effects. Because anti-angiogenic therapy is likely cytostatic, long-term delivery of angiogenesis inhibitors may be required for the successful treatment of cancer. We have, therefore, explored the utility of a gene therapy-mediated approach for the delivery of interferon-beta and tested this approach, both alone and in combination with conventional chemotherapy, in murine models of neuroblastoma.

Adeno-Associated Virus Vector-Mediated Systemic Delivery of IFN-β Combined with Low-Dose Cyclophosphamide Affects Tumor Regression in Murine Neuroblastoma Models

PURPOSE

Type I IFNs (IFN-alpha/beta) have shown significant antitumor activity in preclinical models but limited efficacy and significant toxicity in clinical trials. We hypothesized that the antitumor activity of type I IFNs could be enhanced by chronic, low-dose systemic delivery and sought to test this in murine neuroblastoma models.

EXPERIMENTAL DESIGN

Continuous liver-generated expression of human IFN-beta (hINF-beta) was achieved through a gene therapy-mediated approach using adeno-associated virus vectors encoding hIFN-beta (AAV hINF-beta). Orthotopic localized retroperitoneal and disseminated models of neuroblastoma were established using three different xenografts. Immunohistochemical analysis and ELISA were used to evaluate the antiangiogenic effect of therapy.

RESULTS

The development of both localized orthotopic (retroperitoneal) and disseminated neuroblastoma was prevented in all mice expressing hINF-beta. Continued growth of established retroperitoneal tumors, treated with AAV hINF-beta as monotherapy, was significantly restricted, and survival for mice with established, disseminated disease was significantly prolonged following administration of AAV hINF-beta. Analysis of treated tumors revealed a significant antiangiogenic effect. Mean intratumoral vessel density was diminished and expression of the angiogenic factors vascular endothelial growth factor and basic fibroblast growth factor were both decreased. Finally, combination therapy in which AAV hIFN-beta was used together with low-dose cyclophosphamide resulted in regression of both established retroperitoneal and disseminated disease.

CONCLUSIONS

AAV-mediated delivery of hIFN-beta when used as monotherapy was able to restrict neuroblastoma growth due in part to inhibition of angiogenesis. When used in combination with conventional chemotherapy, AAV hIFN-beta was able to effect complete tumor regression.

Careful decoy receptor titering is required to inhibit tumor angiogenesis while avoiding adversely altering VEGF bioavailability

To inhibit tumor-induced angiogenesis, the VEGF signaling pathway was targeted using AAV vectors encoding a VEGF decoy receptor, a truncated, soluble form of the murine VEGF receptor-2 (tsFlk-1). This approach initially had significant anti-neuroblastoma efficacy in murine xenograft models of local and metastatic disease, but when higher circulating levels of tsFlk-1 were established, tumor growth was more aggressive than even in control mice. Part of the mechanism for this apparent tumor resistance was increased human VEGF expression by the tumor cells. However, further investigation revealed that although a greater amount of VEGF could be bound by higher levels of tsFlk-1, more VEGF also existed in an unbound state and was, therefore, available to support angiogenesis. This novel, tumor-independent mechanism for resistance to antiangiogenic strategies suggests that careful titering of angiogenesis inhibitors may be required to achieve maximal antitumor efficacy and avoid therapy resistance mediated, in part, by ligand bioavailability. This has important implications for therapeutic strategies that use decoy receptors and other agents, such as antibodies, to bind angiogenic factors, in an attempt to inhibit tumor neovascularization.

Adeno-associated virus vector-mediated delivery of pigment epithelium-derived factor restricts neuroblastoma angiogenesis and growth

PURPOSE

The purpose of this study was to evaluate the ability of adeno-associated virus (AAV) vector-mediated delivery of pigment epithelium-derived factor (PEDF) to inhibit neuroblastoma (NB) xenograft growth. Pigment epithelium-derived factor was chosen for this study because, in addition to being a potent inhibitor of angiogenesis, it is capable of inducing neuronal differentiation.

METHODS

Cohorts of mice received either recombinant AAV encoding human PEDF (rAAV-hPEDF) at a range of doses or control vector via tail vein. Subsequent hPEDF expression was measured by enzyme-linked immunoassay. After 6 weeks, the mice were given human NB cells by retroperitoneal injection and then killed 5 weeks later. Tumor weight, microvessel density, tumor differentiation, apoptosis, and levels of intratumoral vascular endothelial growth factor (VEGF) expression were determined at that time. In subsequent cohorts of mice, AAV-mediated murine PEDF expression was tested against both human NB xenografts and murine tumors.

RESULTS

In a series of in vitro studies, PEDF was shown to inhibit endothelial cell activation and to stimulate differentiation of NB cell lines. After tail vein injection of rAAV-hPEDF, stable transgene expression was generated and correlated with levels of vector administration. Human NB xenograft growth was restricted by hPEDF in a dose-dependent fashion. Intratumoral VEGF expression and microvessel density were decreased, and tumor cell apoptosis was increased in PEDF-treated mice.

CONCLUSIONS

Treatment with PEDF had a significant impact on NB growth in mice when delivered continuously using a gene therapy-mediated approach. The activity of PEDF appears to be mediated in part by inhibition of tumor-induced angiogenesis through down-regulation of tumor-elaborated VEGF, with subsequent intratumoral apoptosis. Furthermore, hPEDF was able to induce NB differentiation in vitro and in vivo. In addition, antitumor efficacy was seen when mouse PEDF was used to treat syngeneic murine tumors. In our murine models, gene therapy-mediated delivery of PEDF appears promising for the treatment of neuroblastoma.

Restriction of neuroblastoma angiogenesis and growth by interferon-alpha/beta

PURPOSE

We tested the hypothesis that the antiangiogenic activity of the type I interferons (IFNs), could affect tumor engraftment and growth in murine xenograft models of neuroblastoma.

METHODS

Subcutaneous and retroperitoneal human neuroblastoma xenografts were established in SCID mice. Five days after tumor cell inoculation, daily subcutaneous injections of human IFN-alpha at several different doses were initiated and continued for 30 days. The effectiveness of continuous delivery of low-dose interferon was then tested using a gene therapy approach in which an adeno-associated virus vector encoding IFN-beta (rAAV-IFN-beta) was used to mediate expression prior to retroperitoneal tumor implantation.

RESULTS

Subcutaneous and retroperitoneal tumors were significantly smaller in IFN-alpha-treated mice, as compared with control mice. Intratumoral basic fibroblast growth factor and vascular endothelial growth factor expression were also decreased, as was mean intratumoral endothelial cell density. Interestingly, the lower doses of IFN-alpha were more effective than the higher dose. No tumors developed in any of the mice given rAAV-IFN-beta, whereas each of the mice that received control vector developed large tumors.

CONCLUSIONS

Treatment with IFN had a significant impact on neuroblastoma engraftment and growth in mice, particularly when delivered continuously using a gene therapy approach. This activity appears to be mediated in part by inhibition of tumor-induced angiogenesis through the downregulation of tumor-elaborated factors, including basic fibroblast growth factor and vascular endothelial growth factor.

Longterm recombinant adeno-associated, virus-mediated, liver-generated expression of an angiogenesis inhibitor improves survival in mice with disseminated neuroblastoma

BACKGROUND

A gene therapy-mediated approach to the delivery of antiangiogenic agents using adeno-associated virus (AAV) vectors has a number of advantages including the potential for sustained expression. The purpose of this study was to attempt to restrict the growth of disseminated neuroblastoma through delivery of a truncated, soluble form of the vascular endothelial growth factor receptor-2 (VEGFR-2 fetal liver kinase [Flk]-1), a decoy receptor for VEGF.

STUDY DESIGN

Mice underwent portal vein injection of vector, either AAV-CAGG-tsFlk-1 or control vector. Subsequent truncated soluble fetal liver kinase-1 (tsFlk-1) expression was confirmed and quantified by ELISA. After 8 weeks, mice were given human neuroblastoma cells through the tail vein to establish disseminated disease and were sacrificed after 40 days. The weight of liver metastasis was measured. Intrahepatic tumor microvessel density and levels of apoptosis were determined. Survival was assessed in a second cohort of mice.

RESULTS

After intraportal injection of AAV-CAGG-tsFlk-1, high-level, stable transgene expression was generated. Sera from these mice inhibited endothelial cell activation in vitro and Matrigel plug (BD Biosciences) neovascularization in vivo, suggesting that a systemic state of angiogenesis inhibition had been established. After neuroblastoma injection, mice expressing tsFlk-1 had a smaller tumor burden in the liver when sacrificed, as compared with control mice. The decrease in tumor weight in the liver correlated with lower intratumoral microvessel density and higher levels of tumor cell apoptosis in the tsFlk-1-treated tumors, supporting the hypothesis that decreased angiogenesis had occurred. In a second cohort of mice, survival of tsFlk-1-expressing mice after tumor cell challenge was longer than in control mice.

CONCLUSIONS

Longterm in vivo expression of a functional VEGF inhibitor was established using an AAV-mediated gene therapy approach, and it demonstrated antiangiogenic and anticancer efficacy in a murine model of disseminated neuroblastoma.