Paediatric surgery and COVID-19: urgent lessons to be learned.

BACKGROUND: The dissemination of scientific data on coronavirus disease 2019 (COVID-19) continually builds but, in April 2020, could not keep up with the spread of the disease. Through technology, surgeons in Italy and the UK, representing both peak and pre-peak infective time zones, were able to communicate so that the urgent lessons on the huge expected demands of care learned in Italy could be brought to the UK in advance. This paper specifically discusses the issues related to paediatric surgery, currently under-reported in the literature. METHODS: The aim of this paper is to conjoin experience from the field to provide a framework for a safe assessment and treatment of paediatric patients by adopting a systemic approach aimed at reducing the risk of contamination. We reviewed the processes and good practices that were undertaken in contexts of emergency such as in Italy and the UK and then adapted them within the Systems Engineering Initiative for Patient Safety (SEIPS) framework to provide an assessment of how to reorganize the services in order to cope with an unexpected situation. The SEIPS model is the adopted theoretical framework, which allows to analyse the system in its main components with a human factors and ergonomics (HFE) perspective. RESULTS: The results introduce some of the good practices and recommendations developed during the emergency in the surgical scenario with a focus on the paediatric patients. They represent the lessons learned from the combination of the little existing evidence of literature and the experience from surgical teams who responded in an impromptu and unrehearsed way. CONCLUSIONS: Lessons learned from the frontline 'on the fly' during COVID-19 emergency should be consolidated and taken into the future. In order to prepare proactively for the next phases and get ahead of the curve of these hospital accesses, there is a need for a risk assessment of the new clinical pathways with a multidisciplinary approach centred on HFE with the adoption of the SEIPS model and an involvement of all the surgical teams.

Seromuscular grafts for bladder reconstruction: extra-luminal demucosalisation of the bowel.

OBJECTIVE: To develop a robust sterile, fully demucosalized and vascularized seromuscular patch for use as an adjunct to novel bioengineering techniques aimed at augmenting, reconstructing, or replacing the bladder because of endstage disease. To eliminate deep colonic epithelial crypts to prevent the possibility of colonocyte regrowth. To maintain sterility by excluding the possibility of contamination from the bowel contents. METHODS: Pilot studies were performed on euthanized pigs to optimize the technique, with tissue samples examined by immunohistochemistry. In vivo, vascularized seromuscular colonic flaps were created from the bowel exterior in 7 large white hybrid pigs. The dissection was facilitated by placing an inflated Foley catheter within the colonic lumen. The seromuscular ends were approximated with 5/0 Vicryl sutures and excess mucosa intussuscepted within the lumen. Demucosalized flaps were used to augment the bladder by composite cystoplasty and were examined immunohistochemically at 3 months. RESULTS: Pilot studies showed that the technique was successful in creating seromuscular segments with no epithelial remnants. When applied surgically, the seromuscular flaps survived and showed no evidence of colonocyte regrowth at 3 months. CONCLUSION: Extraluminal dissection creates robust seromuscular flaps and prevents both regrowth by colonic epithelial cells and contamination of the tissue by exposure to the bowel contents. This technique should find application in a range of bladder reconstruction techniques, including composite cystoplasty and autoaugmentation.

Generation of a functional, differentiated porcine urothelial tissue in vitro.

BACKGROUND: The primary function of urothelium is to serve as a physical urinary barrier. This function is dependent on features expressed at the molecular level that are acquired during cytodifferentiation. Urothelial cells lose differentiated and functional characteristics when propagated in vitro. OBJECTIVE: To investigate methods of inducing molecular and functional differentiation of normal porcine urothelial (NPU) cells in vitro. DESIGN AND MEASUREMENTS: NPU cells were isolated from normal porcine bladders and propagated in a low-calcium keratinocyte serum-free medium. Effects of 5% fetal bovine serum (FBS) and exogenous calcium were investigated. Molecular differentiation was assessed by immunolabelling for urothelial differentiation-associated proteins (UPIIIa, CK20, ZO-1), and barrier function was assessed by measurement of transepithelial electrical resistance (TER). RESULTS: NPU cell cultures grew as monolayers in low-calcium, serum-free medium. Supplementation with 5% FBS and/or physiological calcium resulted in stratification into basal, intermediate, and superficial cell zones. Superficial cells were positive for UPIIIa, CK20, and ZO-1. TER measurement showed that NPU cells grown with FBS had significantly enhanced barrier function (6,720 ohms.cm(2)+/-1312 SD) compared with cells grown without FBS (102 ohms.cm(2)+/-34 SD; p<0.001). LIMITATIONS: Importantly, our study demonstrates that expression of differentiation-associated immunohistochemical markers by cultured urothelial cells can be regarded as evidence of only morphological differentiation and does not represent a surrogate marker of function. CONCLUSIONS: We have shown that normal porcine bladder urothelium has many cell biological properties equivalent to normal human urothelium, making it an excellent research substitute for difficult-to-obtain tissue. A differentiated, functional barrier urothelium has been produced from porcine bladder urothelial cells propagated in vitro and displays molecular and functional properties equivalent to native urothelium. This tissue has application in developing tissue-engineered bladders with urinary barrier properties and as a research tool for understanding the relationship between molecular and functional tissue differentiation.