Learning of Intracorporal Knot Tying in Minimally Invasive Surgery by Video or Expert Instruction.

INTRODUCTION: Minimally invasive surgery skill laboratories are indispensable in training, especially for complex procedural skills such as intracorporal suturing and knot tying (ICKT). However, maintaining a laboratory is expensive, and specially trained teachers are in short supply. During the COVID-19 pandemic, in-person instruction has reduced to almost zero, while model learning via video instruction (VID) has become an integral part of medical education. The aim of this study was to compare the learning effectiveness and efficiency of ICKT by laparoscopically inexperienced medical students through video versus direct expert instruction. MATERIALS AND METHODS: A secondary analysis of two randomized controlled trials was performed. We drew data from students who were trained in ICKT with expert instruction (EXP, n = 30) and from students who were trained via VID, n = 30). A laparoscopic box trainer including laparoscope was used for ICKT. Objective Structured Assessment of Technical Skills (OSATS), knot quality, and total ICKT time were the parameters for the assessment in this study. Proficiency criteria were also defined for these parameters. RESULTS: Students in the EXP group performed significantly better in OSATS-procedure-specific checklist (PSC) and knot quality compared with students in the VID group, with no difference in task time. Of the students who reached the proficiency criteria for OSATS-PSC and knot quality, those in the EXP group required fewer attempts to do so than those in the VID group. Students in both groups improved significantly in all parameters over the first hour of evaluation. CONCLUSION: For the laparoscopically inexperienced, training in ICKT through expert instruction presents an advantage compared with video-based self-study in the form of faster understanding of the procedure and the associated consistent implementation of good knot quality. Both teaching methods significantly improved participants' ICKT skills.

A complementary study approach unravels novel players in the pathoetiology of Hirschsprung disease.

Hirschsprung disease (HSCR, OMIM 142623) involves congenital intestinal obstruction caused by dysfunction of neural crest cells and their progeny during enteric nervous system (ENS) development. HSCR is a multifactorial disorder; pathogenetic variants accounting for disease phenotype are identified only in a minority of cases, and the identification of novel disease-relevant genes remains challenging. In order to identify and to validate a potential disease-causing relevance of novel HSCR candidate genes, we established a complementary study approach, combining whole exome sequencing (WES) with transcriptome analysis of murine embryonic ENS-related tissues, literature and database searches, in silico network analyses, and functional readouts using candidate gene-specific genome-edited cell clones. WES datasets of two patients with HSCR and their non-affected parents were analysed, and four novel HSCR candidate genes could be identified: ATP7A, SREBF1, ABCD1 and PIAS2. Further rare variants in these genes were identified in additional HSCR patients, suggesting disease relevance. Transcriptomics revealed that these genes are expressed in embryonic and fetal gastrointestinal tissues. Knockout of these genes in neuronal cells demonstrated impaired cell differentiation, proliferation and/or survival. Our approach identified and validated candidate HSCR genes and provided further insight into the underlying pathomechanisms of HSCR.