Immunosuppression minimization is safe and associated with good long-term success in pediatric recipients of liver transplant

Immunosuppression reduction after liver transplant is an important strategy to mitigate long-term medication side effects. We describe our center's experience with immunosuppression minimization to once-daily calcineurin inhibitor dosing. Success was defined as continuing daily calcineurin inhibitor monotherapy with normal transaminases and no rejection. We performed a retrospective review of eligible children who received a liver transplant between 2009 and 2016, had a surveillance biopsy, and were on twice-daily calcineurin inhibitor monotherapy. Twenty-eight of 51 eligible patients were minimized to daily calcineurin inhibitor with goal 12-hour trough detectable. Nineteen patients (68%) had 1-year success, and 17 (61%) had long-term success at a median follow-up of 5.0 years (interquartile range (IQR): 2.9-6.6). Minimization failure occurred at a median of 0.6 years (IQR: 0.3-1.0) after dose reduction. Patients with long-term success had lower aspartate aminotransferase levels prior to minimization compared to those who failed with a median of 28.0 IU/L (IQR: 20.5-32.0) versus 32.0 IU/L (IQR: 30.0-37.0), p = 0.047. The long-term success group demonstrated a trend toward greater recipients of liver transplant from living donors (53% vs. 18%, p = 0.07). At the time of the last follow-up at a median of 5.0 years (IQR: 2.9-6.1) after surveillance biopsy, most (73%) patients who failed had returned to twice-daily calcineurin inhibitor monotherapy, all had liver enzymes <2 times the upper limit of normal, and there were no patient deaths or graft losses. In conclusion, immunosuppression minimization is safe in pediatric recipients of liver transplant and should be considered to reduce long-term medication side effects and improve patient quality of life. Future studies are necessary to follow long-term outcomes and develop biomarkers to predict minimization success.

Immune biomarker evaluation of sequential tyrosine kinase inhibitor and nivolumab monotherapies in renal cell carcinoma: the phase I TRIBE trial

Background

Predictive biomarkers for immune checkpoint blockade in the second-line treatment of metastatic renal cell carcinoma (mRCC) are lacking.

Materials and methods

Patients with histologically confirmed RCC who started nivolumab after at least 4 months of tyrosine kinase inhibitors (TKIs) were recruited for this study. Serial tissue and blood samples were collected for immune biomarker evaluation. The primary endpoint was to determine the association of specific T-cell subsets with clinical outcomes tested using Wilcoxon rank sum for clinical benefit rate (CBR) and log-rank test for progression-free survival (PFS).

Results

Twenty patients were included in this trial with a median age of 64 years and followed-up for a median of 12 months. The median PFS for patients who received TKI was 13.8 months, while for those subsequently treated with nivolumab following TKI therapy, the median PFS was 2.6 months. CBR of nivolumab was 20% with two partial responses. Functionally active programmed cell death protein 1+ CD4+ T cells were enriched in non-responders (q = 0.003) and associated with worse PFS on nivolumab (P = 0.04). Responders showed a significant reduction in the effector CD4+T-cell (TEF) fraction compared to non-responders at 3 months on nivolumab (0.40 versus 0.80, P = 0.0005). CD127+CD4+ T cells were enriched in patients who developed immune-related adverse effects (q = 0.003). Using in-house validated multiplex immunohistochemistry for six markers, we measured tumour-associated immune cell densities in tissue samples. Responders to nivolumab showed a significantly higher mean of immune cell densities in tissue samples compared to non-responders (346 versus 87 cells/mm2, P = 0.04).

Conclusions

In this small study, analysis of tissue-based and peripheral blood immune cell subsets predicted clinical outcomes of nivolumab. Further studies are warranted with larger populations to validate these observations.

Utilization and perspectives of weight loss medications in pediatric metabolic dysfunction-associated steatotic liver disease

Metabolic dysfunction-associated steatotic liver disease (MASLD) is increasing globally in pediatric populations. Currently, MASLD management primarily relies on lifestyle interventions, which pose challenges in sustaining long-term weight loss. This study investigated the use of weight loss medications in MASLD care through an international survey of 166 pediatric gastroenterologists and hepatologists. The results indicated a notable interest in weight loss medications, with 38% of practitioners considering or using them, particularly glucagon-like peptide-1 receptor agonists. However, the survey also revealed a tendency among clinicians to refer patients to specialists, emphasizing the potential gap between acknowledgment and prescription practices. Challenges include the lack of guidelines and uncertainty regarding side effects. The study highlights a pressing need for education, with over 90% of the respondents expressing an interest. Our study highlights the current management of MASLD, the potential role of pharmacotherapy, and highlights avenues for improved care and education in this dynamic field.

Omicron Infections in Vaccinated Pediatric Solid Organ Transplant Recipients

SARS-CoV-2 infection during the Omicron period was frequent amongst a cohort of vaccinated pediatric solid organ transplant recipients (pSOTRs) despite robust anti-receptor-binding domain (anti-RBD) antibody response, suggesting poor neutralizing capacity against Omicron subvariants. Breakthrough infections among pSOTRs were overall limited in severity.

Anti-spike antibody durability after SARS-CoV-2 vaccination in adolescent solid organ transplant recipients

BACKGROUND

Adolescent solid organ transplant recipients (aSOTRs) who received three doses of the COVID-19 mRNA vaccine experience high seroconversion rates and antibody persistence for up to 3 months. Long-term antibody durability beyond this timeframe following three doses of the SARS-CoV-2 mRNA vaccine remains unknown. We describe antibody responses 6 months following the third vaccine dose (D3) of the BNT162b2 mRNA vaccination among aSOTRs.

METHODS

Participants in a multi-center, observational cohort who received the third dose of the vaccine were analyzed for antibodies to the SARS-CoV-2 spike protein receptor-binding domain (Roche Elecsys anti-SARS-CoV-2-S positive: ≥0.8, maximum: >2500 U/mL). Samples were collected at 1-, 3-, and 6-months post-D3. Participants were surveyed at each timepoint and at 12-months post-D3.

RESULTS

All 34 participants had positive anti-RBD antibody titers 6 months post-D3. Variations in titers occurred between 3 and 6 months post-D3, with 8/28 (29%) having decreased antibody levels at 6 months compared to 3 months and 2/28 (7%) reporting increased titers at 6 months. The remaining 18/28 (64%) had unchanged antibody titers compared to 3-month post-D3 levels. A total of 4/34 (12%) reported breakthrough infection within 6 months and 3/32 (9%) reported infection after 6-12 months following the third dose of the SARS-CoV-2 mRNA vaccine.

CONCLUSIONS

The results suggest that antibody durability persists up to 6 months following three doses of the SARS-CoV-2 mRNA in aSOTRs. Demography and transplant characteristics did not differ for those who experienced antibody weaning. Breakthrough infections did occur, reflecting immune-evasive nature of novel variants such as Omicron.

Clinicopathologic Features of Severe Acute Hepatitis Associated With Adenovirus Infection in Children

A recent increase in reports of severe acute hepatitis of unknown etiology in children is under investigation. Although adenovirus has been frequently detected, its role remains unclear, and systematic histopathologic analysis is lacking. We conducted a retrospective study of 11 children hospitalized between October 2021 and May 2022 with unexplained acute hepatitis and concurrent adenovirus infection. Liver biopsies collected shortly after admission demonstrated moderately to severely active hepatitis in 8/11 (73%) cases, characterized by marked portal mixed inflammation, moderate-to-severe interface activity, and milder lobular inflammation. Clusters of plasma cells were present in 6/11 (55%) cases, mimicking autoimmune hepatitis. Semiquantitative scoring of 17 discrete histologic features found that greater degrees of portal inflammation, interface activity, bile duct injury, bile ductular reaction, lobular inflammation, Kupffer cell activation, and hepatocyte focal necrosis were significantly more common in these cases in comparison to the control group of unexplained acute severe hepatitis without adenovirus infection. Liver biopsy immunohistochemistry was negative for adenovirus in all cases. Polymerase chain reaction testing of liver tissue was positive for the enteric adenovirus serotypes 41 (species F) in 10/11 (91%) cases. An immunoprofile study of hepatic infiltrating lymphocytes in 1 patient revealed the presence of large numbers of CD3 + and CD4 + lymphocytes. Nine patients received supportive treatment without steroids and recovered without the need for liver transplantation. In summary, liver injury in children with severe acute hepatitis and adenovirus infection is characterized by a hepatitic pattern that resembles severe autoimmune hepatitis and may represent an immune-mediated process associated with viral infection.

Living donor liver transplantation: A multi-disciplinary collaboration towards growth, consensus, and a change in culture

INTRODUCTION

Living donor liver transplantation (LDLT) reduces liver transplant waitlist mortality and provides excellent long-term outcomes for persons with end stage liver disease. Yet, utilization of LDLT has been limited in the United States (US).

METHODS

In October 2021, the American Society of Transplantation held a consensus conference to identify important barriers to broader expansion of LDLT in the US, including data gaps, and make recommendations for impactful and feasible mitigation strategies to overcome these barriers. Domains addressed encompassed the entirety of the LDLT process. Representation from international centers and living donor kidney transplantation were included for their perspective/experience in addition to members across disciplines within the US liver transplantation community. A modified Delphi approach was employed as the consensus methodology.

RESULTS

The predominant theme permeating discussion and polling results centered on culture; the beliefs and behaviors of a group of people perpetuated over time.

CONCLUSIONS

Creating a culture of support for LDLT in the US is key for expansion and includes engagement and education of stakeholders across the spectrum of the process of LDLT. A shift from awareness of LDLT to acknowledgement of benefit of LDLT is the primary goal. Propagation of the maxim "LDLT is the best option" is pivotal.

Feasibility of using a patient-reported outcome measure into clinical practice following pediatric liver transplantation: The Starzl Network experience

BACKGROUND

Patient-reported outcome measures (PROMs) are not routinely used in clinical care by pediatric liver transplant (LT) teams. The Starzl Network for Excellence in Pediatric Transplantation (SNEPT) assessed feasibility of using a disease-specific Quality of Life (QoL) questionnaire in the ambulatory setting at 10 SNEPT sites.

METHODS

A mixed methods feasibility project assessing administration processes, barriers, and user experiences with the Pediatric Liver Transplant Quality of Life (PeLTQL) tool. Iterative processes sought stakeholder feedback across four phases (Pilot, Extended Pilot, Development of a Mobile App PeLTQL version, and Pilot App use).

RESULTS

A total of 149 patient-parent dyads completed the PeLTQL during LT clinic follow-up. Clinicians, parents, and patients evaluated and reported on feasibility of operationalization. Only two of 10 SNEPT sites continued PeLTQL administration after the initial two pilot phases. Reasons include limited clinical time and available personnel aggravated by the COVID-19 pandemic. In response, a mobile application version of the PeLTQL was initiated. Providing PeLTQL responses electronically was "very easy" or "easy" as reported by 96% (22/23) parents.

CONCLUSIONS

Administration of a PROM into post-pediatric LT clinical care was feasible, but ongoing utilization stalled. Use of a mobile app towards facilitating completion of the PeLTQL outside of clinic hours may address the time and work-flow barriers identified.

Does Instrumentation of the Fractured Level in Thoracolumbar Fixation Affect the Functional and Radiological Outcome?

STUDY DESIGN

Retrospective comparative study.

OBJECTIVES

To compare radiological and functional outcomes of patients with fixation constructs utilizing pedicle screw stabilization at the fracture level (FL group) versus patients with non-fracture level (NFL group) fixation in single level fractures of the thoracolumbar junction (T11-L1).

METHODS

53 patients of whom fracture level screw was used in 34 (FL group) were compared to 19 patients in NFL group. Radiological parameters analyzed were sagittal index, bi-segmental kyphosis (Cobb) angle and degree of vertebral height restoration. Prospectively collected patient reported functional outcomes and post-operative complications were also studied. Stepwise regression analysis adjusted by age, gender and functional scores was performed to account for the small numbers and unequal sizes of the groups.

RESULTS

Back pain score was significantly lower in the FL group (P < 0.025). Core Outcome Measures Index scores and leg pain scores, though low in the FL group, were not statistically significant. The regression analysis showed that the inclusion of the fracture-level screw was independently associated with a greater change in sagittal index and vertebral height restoration post-operatively. Sagittal index was maintained through to final follow up as well. The bi-segmental Cobb's angle correction was not associated with fracture-level screw construct. There was no significant difference between the groups for revision surgery, deep infection, implant failure or length of hospital stay.

CONCLUSION

The inclusion of the fracture-level pedicle screws in the fixation construct significantly improves the immediate and final measured radiological parameters, with improved functional scores in single level unstable vertebral fractures of the thoracolumbar junction.

Early thrombotic and hemorrhagic complications associated with a risk-adjusted postoperative anticoagulation protocol after pediatric liver transplantation

BACKGROUND

Systemic anticoagulation after pediatric liver transplantation (pLT) is believed to reduce the incidence of vascular thrombosis, but it may also cause an increase in hemorrhagic complications.

PROCEDURE

A 5-year retrospective review of pLT done at our institution was performed (2014-2018). The occurrence of early hemorrhagic and thrombotic complications was compared when using low-dose or high-dose anticoagulation after transplant (p < .05 considered significant).

RESULTS

Sixty-nine patients received 73 transplants during the study period. Median age at transplant was 2.3 years (40 days to 18.5 years). Low-dose anticoagulation was utilized in 71% cases. Additionally, six patients were converted from low-dose to high-dose anticoagulation because of a thrombotic event or concerns for suboptimal vascular inflow. Postoperative anticoagulation was discontinued in 18 occurrences due to bleeding (low dose 19%, high dose 47% vs. low dose to high dose 17%, p = .085). Surgical take back for bleeding occurred in 17 occasions (low dose 13.5%, high dose 53% vs. low dose to high dose 33%, p = .005). The overall incidence of hepatic artery thrombosis (HAT) and portal vein thrombosis were each 5.5%, respectively. While patient survival was not statistically different between groups, graft survival was significantly lower in the high-dose group (low dose 93%, high dose 73% vs. low dose to high dose 100%, p = .046). However, graft losses from HAT were similar between groups (low dose 2%, high dose 7% vs. low dose to high dose 0%, p = .56).

CONCLUSION

The use of a standardized risk-adjusted anticoagulation protocol after pLT is associated with a low occurrence of thrombotic and hemorrhagic complications. High-dose anticoagulation leads to more bleeding, but those risks outweigh the risks of possible graft loss.

Randomized placebo-controlled trial of losartan for pediatric NAFLD

BACKGROUND AND AIMS

To date, no pharmacotherapy exists for pediatric NAFLD. Losartan, an angiotensin II receptor blocker, has been proposed as a treatment due to its antifibrotic effects.

APPROACH AND RESULTS

The Nonalcoholic Steatohepatitis Clinical Research Network conducted a multicenter, double-masked, placebo-controlled, randomized clinical trial in children with histologically confirmed NAFLD at 10 sites (September 2018 to April 2020). Inclusion criteria were age 8-17 years, histologic NAFLD activity score ≥ 3, and serum alanine aminotransferase (ALT) ≥ 50 U/l. Children received 100 mg of losartan or placebo orally once daily for 24 weeks. The primary outcome was change in ALT levels from baseline to 24 weeks, and the preset sample size was n = 110. Treatment effects were assessed using linear regression of change in treatment group adjusted for baseline value. Eighty-three participants (81% male, 80% Hispanic) were randomized to losartan (n = 43) or placebo (n = 40). During an enrollment pause, necessitated by the 2019 coronavirus pandemic, an unplanned interim analysis showed low probability (7%) of significant group difference. The Data and Safety Monitoring Board recommended early study termination. Baseline characteristics were similar between groups. The 24-week change in ALT did not differ significantly between losartan versus placebo groups (adjusted mean difference: 1.1 U/l; 95% CI = -30.6, 32.7; p = 0.95), although alkaline phosphatase decreased significantly in the losartan group (adjusted mean difference: -23.4 U/l; 95% CI = -41.5, -5.3; p = 0.01). Systolic blood pressure decreased in the losartan group but increased in placebo (adjusted mean difference: -7.5 mm Hg; 95% CI = -12.2, -2.8; p = 0.002). Compliance by pill counts and numbers and types of adverse events did not differ by group.

CONCLUSIONS

Losartan did not significantly reduce ALT in children with NAFLD when compared with placebo.

Graft Fibrosis Over 10 to 15 Years in Pediatric Liver Transplant Recipients: Multicenter Study of Paired, Longitudinal Surveillance Biopsies

Previous single-center, cross-sectional studies have reported a steep increase in the prevalence and severity of fibrosis through 10 to 15 years after pediatric liver transplantation. We report a multicenter study of paired surveillance biopsies in a contemporary cohort. Children who underwent liver transplant when younger than 6 years old and had paired surveillance liver biopsies were enrolled (n = 78, 35% girls, median 1.2 years old at transplant). A central pathologist graded inflammation, assessed rejection activity index, and staged fibrosis in the portal, sinusoidal, and perivenular compartments, allowing for calculation of the Liver Allograft Fibrosis Score (LAFSc). Analysis of variance tested associations between fibrosis progression and clinical parameters. The first biopsy, at a median 8.2 years (interquartile range, 5.9-11.6 years) after transplantation, showed absent to mild fibrosis (LAFSc 0-2) in 29%, moderate (LAFSc 3-5) in 56%, and severe (LAFSc 6-7) in 14% of patients. The second biopsy, at a median 4.7 years (IQR, 4.3-5.1 years) later, showed fibrosis progression (LAFSc increased by ≥3) in 10 (13%) and regression (LAFSc decreased by ≥3) in 4 (5%) patients. After adjusting for baseline LAFSc, younger age at transplant was the only risk factor for fibrosis progression. Although fibrosis prevalence and severity 6 to 12 years after transplant was similar to previous reports, fibrosis trajectory during the next 4 to 5 years was stable. Our data may be reassuring for children with consistently normal liver tests. A comprehensive understanding of factors determining allograft health during the very long term is essential to optimizing allograft and patient health.

North American Biliary Stricture Management Strategies in Children After Liver Transplantation: A Multicenter Analysis From the Society of Pediatric Liver Transplantation (SPLIT) Registry

Biliary strictures affect 4%-12% of pediatric liver transplantations. Biliary strictures can contribute to graft loss if left untreated; however, there remains no consensus on the best course of treatment. Study objectives included analyses of outcomes associated with biliary stricture management strategies via percutaneous transhepatic cholangiography (PTC), endoscopic retrograde cholangiopancreatography (ERCP), or surgery. We identified pediatric liver transplantation recipients (2011-2016) with biliary strictures from the Society of Pediatric Liver Transplantation (SPLIT) registry and retrieved imaging, procedural, and operative reports from individual centers. Subanalyses were performed to specifically evaluate PTC and ERCP for "optimal biliary outcome" (OBO), defined as graft survival with stricture resolution and without recurrence or surgery. A total of 113 children with a median follow-up of 3.9 years had strictures diagnosed 100 days (interquartile range, 30-290) after liver transplantation; 81% were isolated anastomotic strictures. Stricture resolution was achieved in 92% within 101 days, more frequently with isolated anastomotic strictures (96%). 20% of strictures recurred, more commonly in association with hepatic artery thrombosis (32%). Patient and graft survival at 1 and 3 years were 99% and 98% and 94% and 92%, respectively. In a subgroup analysis of 79 patients with extrahepatic strictures managed by PTC/ERCP, 59% achieved OBO following a median of 4 PTC, and 75% following a median of 3 ERCP (P < 0.001). Among patients with OBO, those with ERCP had longer time intervals between successive procedures (41, 47, 54, 62, 71 days) than for PTC (27, 31, 36, 41, 48 days; P < 0.001). Allograft salvage was successful across all interventions. Stricture resolution was achieved in 92%, with 20% risk of recurrence. Resolution without recurrence was highest in patients with isolated anastomotic strictures and without hepatic artery thrombosis.

Live virus vaccination following pediatric liver transplantation: Outcomes from two academic children's hospitals

Pediatric liver transplant (LT) recipients are often transplanted at a young age, precluding them from receiving live virus vaccinations (LVV) such as varicella (VZV) vaccine and measles, mumps and rubella. This places them at profound risk for vaccine preventable illness. We sought to detail safety of vaccination. This was a retrospective cohort study of pediatric LT recipients at two children's hospitals. Among 204 LT recipients included in the study, 97 received at least one LVV after LT. Six patients who did not receive LVV after transplant had evidence of vaccine-preventable infection following vaccination (one disseminated VZV disease, five VZV-related rash), while one patient who received LVV after transplant developed a diffuse VZV-related rash. Rejection rates were the same between those that did and did not receive a live virus vaccine post-transplant. There were no serious adverse events caused by vaccination post-transplant. LVV following LT was safe at our two institutions, although there exist limitations in our study due to its retrospective study design. Larger scale studies should be performed to evaluate the effectiveness of LVV in relation to immunosuppression.

Normal long-term neurologic and graft outcome after liver transplantation in an infant with Neimann-Pick type C disease

Niemann-Pick type C disease is a rare autosomal recessive lysosomal disorder that leads to the accumulation of lipids in cellular organelles. Affected infants are often cholestatic with hepatosplenomegaly, developmental delay and may present in acute liver failure. Medical therapy has shown some promise in long-term studies, in patients with milder phenotypes of the disease. Liver transplantation has generally not been considered a therapeutic option due to the systemic nature of the condition, and frequent unremitting neurological decline leading to death. We report an infant with multisystem organ failure, and known Niemann-Pick C disease who was successfully transplanted and has maintained normal neurological outcomes now five years after transplantation. We highlight the need for multidisciplinary care in order to recognize different phenotypes that may exist, even in rare diseases, and to be aware of evolving therapeutic options.

The current state of pediatric transplant hepatology fellowships: A survey of recent graduates

BACKGROUND

The number of programs offering a PTH fellowship has grown rapidly over the last 10 years. This study aimed to describe the clinical, didactic, procedural, and research experiences of recent PTH fellowship graduates. In addition, we sought to understand graduates' post-fellowship professional responsibilities and their perception about the utility of the PTH fellowship.

METHODS

An anonymous survey was distributed from February to October 2020 through REDCap to all recent graduates (2015-2019) of an ACGME-approved PTH fellowship program. The survey consisted of 49 questions focused on the PTH fellowship experience. Results were summarized using descriptive statistics.

RESULTS

Thirty-eight of 43 graduates (88%) responded to the survey representing 12 PTH fellowship programs. The didactic experience varied; 97% received pathology lectures, 81% radiology lectures, 54% organ allocation lectures, 54% procedural lectures, 57% immunology lectures, and 43% live donation lectures. During the PTH fellowship, the majority of fellows performed >10 liver biopsies (82%) and >5 variceal bandings (58%); however, 63%, 32%, 8%, and 8% never performed paracentesis, variceal sclerotherapy, variceal banding, and liver biopsies, respectively. The majority of fellows (95%) completed a research project during PTH fellowship. Currently, 84% of graduates are employed at a transplant academic institution. All graduates recommended the fellowship.

CONCLUSIONS

There is variability in the didactic, clinical, and procedural training among PTH fellowship programs. Although uniformly viewed as a beneficial fellowship year, there is an opportunity to collaborate to create a more standardized training experience.

Metabolomics to understand placental biology: Where are we now?

Metabolomics, the application of analytical chemistry methodologies to survey the chemical composition of a biological system, is used to globally profile and compare metabolites in one or more groups of samples. Given that metabolites are the terminal end-products of cellular metabolic processes, or 'phenotype' of a cell, tissue, or organism, metabolomics is valuable to the study of the maternal-fetal interface as it has the potential to reveal nuanced complexities of a biological system as well as differences over time or between individuals. The placenta acts as the primary site of maternal-fetal exchange, the success of which is paramount to growth and development of offspring during pregnancy and beyond. Although the study of metabolomics has proven moderately useful for the screening, diagnosis, and understanding of the pathophysiology of pregnancy complications, the placental metabolome in the context of a healthy pregnancy remains poorly characterized and understood. Herein, we discuss the technical aspects of metabolomics and review the current literature describing the placental metabolome in human and animal models, in the context of health and disease. Finally, we highlight areas for future opportunities in the emerging field of placental metabolomics.

227 Multiple Outbreak Of SARS-COVID-19 In Surgical Wards at The Tertiary Hospital

Background

Since the second surge of SARS-COVID-19 on 18th of September, additional several measures were introduced, and pathways created in order to execute safe surgical practices and protect both patients and staff from SARS-COVID-19. Despite these measures, there have been reported cases of outbreaks in various parts of UK amongst patients and clinical staff.

Method

Three outbreaks in the past 6 weeks (10, September 2020 to 21, October 2020) were reported in our surgical wards and we compiled the timing, initial source, number of affected individuals and immediate management steps taken.

Results

Following the first outbreak on wards, 28-day surveillance helped us understand responsible variants. Several staff members were found walking out of hospital, in groups once they had removed their PPEs. Communal lunching with inadequate social distancing, attending work with symptoms (albeit atypical for COVID), sharing cars to/from work or not wearing PPE correctly were highlighted in the subsequent investigations. The reduction in number of affected individuals during the last two incidents reflected a degree of efficacy of the implemented preventative measures, which were reviewed again following the subsequent incidents.

Conclusions

In the present climate, a robust and prompt response to outbreaks is required. Continual iteration with regards to the need for PPE, adequate social distancing and avoiding over-crowding in communal areas is paramount to reduce the probability of ward outbreaks and inter-professional transmission. Asymptomatic staff testing, particularly in high-risk areas could also be considered but would require adequate laboratory capacity and rapid turnaround of test results.

Revision pedicle screws with impaction bone grafting: a case series

BACKGROUND

Pedicle screw fixation in spinal constructs can be subject to failure requiring revision surgery. In cases of aseptic loosening various salvage techniques have been described. Revision screws augmented with cement have become popular but are not without risks. Larger diameter screws are often used but result in reducing bone stock or expanding the pedicles. We present a novel technique of pedicle screw revision by impaction bone allografting and a case series.

METHODS

The failed screws are removed. The screw track is probed to check its integrity. Milled bone allograft is funneled into the screw hole and sequentially impacted, before insertion of a replacement screw. We report a case series and describe a single case where this method has been used. Information was gathered from the electronic patient record in our hospital.

RESULTS

Ten screws were revised in 7 patients. Mean age at first surgery was 60.86 (48-76) years. Average time between first surgery and revision was 12.6 (4.7-49.9) months. Average follow-up was 26.2 (5.7-62.2) months and no screws showed any signs of loosening.

CONCLUSIONS

Impaction grafting with bone allograft is a technique for pedicle screw salvage that can be used safely and effectively as an alternative to cemented screws, when pedicle screws have failed by aseptic loosening. It avoids the risks associated with cemented screws and in our series was successful.

Validating a Low-Fidelity Model for Microsurgical Anastomosis Training

With cost, size, and availability in mind, we developed a low-fidelity microsurgery anastomosis model for mastery of the tool skills needed to execute microsurgical procedures. The model combined the use of a cannulated Konnyaku Shirataki (KS) noodle with a low-cost, industrial inspection, trinocular stereo (IITS) microscope. The purpose of this study was to establish face and construct validity of this novel "combined" microsurgery training tool.

Methods

Fifteen participants, divided into 3 groups based on microsurgery experience, attempted microsurgical anastomoses of a cannulated KS noodle using the IITS microscope. Participants were asked to (1) manipulate the noodle ends adjacent to each other, (2) place a single 7-0 nylon suture through the opposed ends, and (3) complete the anastomosis. To determine construct validity, the performance of the microsurgical repair (maximum score 53 points) and time-to-anastomosis was assessed. To determine face validity, microsurgeons were given a 25-item, 5-point scale survey rating their experience with the model.

Results

Participants included 5 microsurgeons, 5 experienced trainees, and 5 novices. The microsurgeons judged the IITS microscope to be a close analog to an operating microscope (4.6/5 points), the combined model to have high educational value (4.7/5 points), and somewhat technical similarity with microsurgery in the operating room (OR) (3.7/5 points). The median technical score was 50 among microsurgeons, 40 among experienced trainees, and 27 among novices. Increased training level was associated with greater technical score among all 3 groups (p=0.002). The median time-to-anastomosis was 5.88 minutes for microsurgeons, 8.37 minutes for experienced trainees, and 17.10 minutes for novices. Increased training level was associated with shorter time-to-anastomosis (p=0.003).

Conclusion

The use of the KS noodle with a benchtop stereo microscope is a novel approach to microsurgical training. It is inexpensive, available, conducive to high-repetition training, and suited to many learning environments. Microsurgeons found that this combined model was representative of microsurgery in the OR, and we concluded face validity. Furthermore, an association was demonstrated between training level and performance on the model, suggesting construct validity.

Severe Acute Respiratory Syndrome Coronavirus-2 Infection in Children With Liver Transplant and Native Liver Disease: An International Observational Registry Study

OBJECTIVE

Increased mortality risk because of severe acute respiratory syndrome coronavirus-2 (SARS-CoV2) infection in adults with native liver disease (LD) and liver transplant (LT) is associated with advanced age and comorbid conditions. We aim to report outcomes for children with LD and LT enrolled in the NASPGHAN/SPLIT SARS-CoV2 registry.

METHODS

In this multicenter observational cohort study, we collected data from 91 patients <21 years (LD 44, LT 47) with laboratory-confirmed SARS-CoV2 infection between April 21 and September 17, 2020.

RESULTS

Patients with LD were more likely to require admission (70% vs 43% LT, P = 0.007) and pediatric intensive care unit (PICU) management (32% vs 4% LT, P = 0.001). Seven LD patients required mechanical ventilation (MV) and 2 patients died; no patients in the LT cohort died or required MV. Four LD patients presented in pediatric acute liver failure (PALF), 2 with concurrent multisystem inflammatory syndrome in children (MIS-C); all recovered without LT. Two LD patients had MIS-C alone and 1 patient died. Bivariable logistic-regression analysis found that patients with nonalcoholic fatty LD (NAFLD) (odds ratio [OR] 5.6, P = 0.02) and LD (OR 6.1, P = 0.01, vs LT) had higher odds of severe disease (PICU, vasopressor support, MV, renal replacement therapy or death).

CONCLUSIONS

Although not directly comparable, LT recipients had lower odds of severe SARS-CoV2 infection (vs LD), despite immunosuppression burden. NAFLD patients reported to the registry had higher odds of severe SARS-CoV2 disease. Future controlled studies are needed to evaluate effective treatments and further stratify LD and LT patients with SARS-CoV2 infection.