Clinical Relevance of Pathological Diagnosis of Hirschsprung's Disease with Acetylcholine-Esterase Histochemistry or Calretinin Immunohistochemistry.

INTRODUCTION: Hirschsprung disease (HD) manifests as a developmental anomaly affecting the enteric nervous system, where there is an absence of ganglion cells in the lower part of the intestine. This deficiency leads to functional blockages within the intestines. HD is usually confirmed or ruled out through rectal biopsy. The identification of any ganglion cells through hematoxylin and eosin (H&E) staining rules out HD. If ganglion cells are absent, further staining with acetylcholine-esterase (AChE) histochemistry or calretinin immunohistochemistry (IHC) forms part of the standard procedure for determining a diagnosis of HD. In 2017, our Institute of Pathology at University Hospital of Heidelberg changed our HD diagnostic procedure from AChE histochemistry to calretinin IHC. In this paper, we report the impact of the diagnostic procedure change on surgical HD therapy procedures and on the clinical outcome of HD patients. METHODS: We conducted a retrospective review of the diagnostic procedures, clinical data, and postoperative progress of 29 patients who underwent surgical treatment for HD in the Department of Pediatric Surgery, University of Heidelberg, between 2012 and 2021. The patient sample was divided into two groups, each covering a treatment period of 5 years. In 2012-2016, HD diagnosis was performed exclusively using AChE histochemistry (AChE group, n = 17). In 2017-2021, HD diagnosis was performed exclusively using calretinin IHC (CR group, n = 12). RESULTS: There were no significant differences between the groups in sex distribution, weeks of gestation, birth weight, length of the aganglionic segment, or associated congenital anomalies. Almost half of the children in the AChE group, twice as many as in the CR group, required an enterostomy before transanal endorectal pull-through procedure (TERPT). In the AChE group, 4 patients (23.5%) required repeat bowel sampling to confirm the diagnosis. Compared to the AChE group, more children in the CR group suffered from constipation post TERPT. DISCUSSION: Elevated AChE expression is linked to hypertrophied extrinsic cholinergic nerve fibers in the aganglionic segment in the majority of patients with HD. The manifestation of increased AChE expression develops over time. Therefore, in neonatal patients with HD, especially those in the first 3 weeks of life, an increase in AChE reaction is not detected. Calretinin IHC reliably identifies the presence or absence of ganglion cells and offers multiple benefits over AChE histochemistry. These include the ability to perform the test on paraffin-embedded tissue sections, a straightforward staining pattern, a clear binary interpretation (negative or positive), cost-effectiveness, and utility regardless of patient age. CONCLUSIONS: The ability of calretinin IHC to diagnose HD early and time-independently prevented repeated intestinal biopsies in our patient population and allowed us to perform a one-stage TERPT in the first months of life, reducing the number of enterostomies and restoring colonic continuity early. Patients undergoing transanal pull-through under the age of 3 months require a close follow-up to detect cases with bowel movement problems.

Human peritoneal tight junction, transporter and channel expression in health and kidney failure, and associated solute transport.

Next to the skin, the peritoneum is the largest human organ, essentially involved in abdominal health and disease states, but information on peritoneal paracellular tight junctions and transcellular channels and transporters relative to peritoneal transmembrane transport is scant. We studied their peritoneal localization and quantity by immunohistochemistry and confocal microscopy in health, in chronic kidney disease (CKD) and on peritoneal dialysis (PD), with the latter allowing for functional characterizations, in a total of 93 individuals (0-75 years). Claudin-1 to -5, and -15, zonula occludens-1, occludin and tricellulin, SGLT1, PiT1/SLC20A1 and ENaC were consistently detected in mesothelial and arteriolar endothelial cells, with age dependent differences for mesothelial claudin-1 and arteriolar claudin-2/3. In CKD mesothelial claudin-1 and arteriolar claudin-2 and -3 were more abundant. Peritonea from PD patients exhibited increased mesothelial and arteriolar claudin-1 and mesothelial claudin-2 abundance and reduced mesothelial and arteriolar claudin-3 and arteriolar ENaC. Transperitoneal creatinine and glucose transport correlated with pore forming arteriolar claudin-2 and mesothelial claudin-4/-15, and creatinine transport with mesothelial sodium/phosphate cotransporter PiT1/SLC20A1. In multivariable analysis, claudin-2 independently predicted the peritoneal transport rates. In conclusion, tight junction, transcellular transporter and channel proteins are consistently expressed in peritoneal mesothelial and endothelial cells with minor variations across age groups, specific modifications by CKD and PD and distinct associations with transperitoneal creatinine and glucose transport rates. The latter deserve experimental studies to demonstrate mechanistic links.Clinical Trial registration: The study was performed according to the Declaration of Helsinki and is registered at www.clinicaltrials.gov (NCT01893710).

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.

Associations of Mucosal Nerve Fiber Innervation Density with Hirschsprung-Associated Enterocolitis: A Retrospective Three-Center Cohort Study.

OBJECTIVE: Hirschsprung's disease (HSCR) is a congenital intestinal neurodevelopmental disorder characterized by the absence of enteric ganglion cells in the distal colon. Although Hirschsprung-associated enterocolitis (HAEC) is the most frequent life-threatening complication in HSCR, to date reliable biomarkers predicting the likelihood of HAEC are yet to be established. We established a three-center retrospective study including 104 HSCR patients surgically treated between 1998 and 2019. MATERIALS AND METHODS: Patient-derived cryopreserved or paraffin-preserved colonic tissue at surgery was analyzed via ßIII-tubulin immunohistochemistry. We subsequently determined extrinsic mucosal nerve fiber density in resected rectosigmoid specimens and classified HSCR patients accordingly into nerve fiber-high or fiber-low groups. We compared the distribution of clinical parameters obtained from medical records between the fiber-high (n = 36) and fiber-low (n = 68) patient groups. We assessed the association between fiber phenotype and enterocolitis using univariate and multivariate logistic regression adjusted for age at operation. RESULTS: Enterocolitis was more prevalent in patients with sparse mucosal nerve fiber innervation (fiber-low phenotype, 87%) compared with the fiber-high phenotype (13%; p = 0.002). In addition, patients developing enterocolitis had a younger age at surgery (3 vs. 7 months; p = 0.016). In the univariate analysis, the odds for enterocolitis development in the fiber-low phenotype was 5.26 (95% confidence interval [CI], 1.67-16.59; p = 0.005) and 4.01 (95% CI, 1.22-13.17; p = 0.022) when adjusted for age. CONCLUSION: Here, we showed that HSCR patients with a low mucosal nerve fiber innervation grade in the distal aganglionic colon have a higher risk of developing HAEC. Consequently, histopathologic analysis of the nerve fiber innervation grade could serve as a novel sensitive prognostic marker associated with the development of enterocolitis in HSCR patients.

The Spaced Learning Concept in Combination With Halsted and Peyton - A Randomized Controlled Study.

BACKGROUND: Several motor learning models have been used to teach highly complex procedural skills in medical education. Two approaches are often employed amongst health care professionals: Halsted's "See one - do one - teach one" concept and Peyton's Four-step approach. Peyton's deconstruction of the learning process into 4 sub-steps was reported to be preferable for learning/acquiring/teaching complex clinical skills. However, a new increasingly popular technique is known as the spaced learning method. In a previous study, we were able to confirm that the spaced learning concept is superior for laparoscopic suturing and knot tying compared to conventional training curricula, this current study aimed to assess the influence of spaced learning in combination with Halsted's and Peyton's tutoring approaches on laparoscopic knot tying of medical students. METHODS: After randomization, 20 medical students were either assigned to Halsted's or Peyton's teaching approach and trained one-on-one (teacher-student). Additionally, all subjects were trained according to the spaced learning concept, containing 40 minutes of content-blocks, followed by a 20-minute break involving coordinated, standardized physical activity. This was repeated three times. Primary endpoints were time, knot quality, precision, knot strength, as well as overall laparoscopic knotting performance and competency. To evaluate the motivation of the subjects, an 18-item questionnaire was utilized to measure four motivational factors (anxiety, probability of success, interest, and challenge). RESULTS: All trainees significantly improved after training in all knot attributes. Trainees assigned to Halsted's method were able to significantly outperform the Peyton group in knot quantity within 30 minutes (p = 0.013), time/knot (p = 0.033), performance score (p = 0.009), and precision (p = 0.032). No significant difference between Halsted and Peyton was found for knot strength and quality. Furthermore, no significant difference was identified comparing motivation pre- and post-training. However, subjects in the Peyton appeared to be significantly more anxious after training. CONCLUSION: Combining spaced learning technique with Halsted's "see one - do one - teach one" appears to be superior to Peyton's Four-step approach in conjunction with spaced learning in surgical naïve students. We recommend further studies evaluating the combination of spaced learning with Halsted and Peyton's instructional methods.

Glucose Derivative Induced Vasculopathy in Children on Chronic Peritoneal Dialysis.

[Figure: see text].

Lack of Mucosal Cholinergic Innervation Is Associated With Increased Risk of Enterocolitis in Hirschsprung's Disease.

BACKGROUND & AIMS: Hirschsprung's disease (HSCR) is a congenital intestinal motility disorder defined by the absence of enteric neuronal cells (ganglia) in the distal gut. The development of HSCR-associated enterocolitis remains a life-threatening complication. Absence of enteric ganglia implicates innervation of acetylcholine-secreting (cholinergic) nerve fibers. Cholinergic signals have been reported to control excessive inflammation, but the impact on HSCR-associated enterocolitis is unknown. METHODS: We enrolled 44 HSCR patients in a prospective multicenter study and grouped them according to their degree of colonic mucosal acetylcholinesterase-positive innervation into low-fiber and high-fiber patient groups. The fiber phenotype was correlated with the tissue cytokine profile as well as immune cell frequencies using Luminex analysis and fluorescence-activated cell sorting analysis of colonic tissue and immune cells. Using confocal immunofluorescence microscopy, macrophages were identified in close proximity to nerve fibers and characterized by RNA-seq analysis. Microbial dysbiosis was analyzed in colonic tissue using 16S-rDNA gene sequencing. Finally, the fiber phenotype was correlated with postoperative enterocolitis manifestation. RESULTS: The presence of mucosal nerve fiber innervation correlated with reduced T-helper 17 cytokines and cell frequencies. In high-fiber tissue, macrophages co-localized with nerve fibers and expressed significantly less interleukin 23 than macrophages from low-fiber tissue. HSCR patients lacking mucosal nerve fibers showed microbial dysbiosis and had a higher incidence of postoperative enterocolitis. CONCLUSIONS: The mucosal fiber phenotype might serve as a prognostic marker for enterocolitis development in HSCR patients and may offer an approach to personalized patient care and new therapeutic options.

Cholinergic Signaling Attenuates Pro-Inflammatory Interleukin-8 Response in Colonic Epithelial Cells.

Infants affected by Hirschsprung disease (HSCR), a neurodevelopmental congenital disorder, lack ganglia of the intrinsic enteric nervous system (aganglionosis) in a variable length of the colon, and are prone to developing severe Hirschsprung-associated enterocolitis (HAEC). HSCR patients typically show abnormal dense innervation of extrinsic cholinergic nerve fibers throughout the aganglionic rectosigmoid. Cholinergic signaling has been reported to reduce inflammatory response. Consequently, a sparse extrinsic cholinergic innervation in the mucosa of the rectosigmoid correlates with increased inflammatory immune cell frequencies and higher incidence of HAEC in HSCR patients. However, whether cholinergic signals influence the pro-inflammatory immune response of intestinal epithelial cells (IEC) is unknown. Here, we analyzed colonic IEC isolated from 43 HSCR patients with either a low or high mucosal cholinergic innervation density (fiber-low versus fiber-high) as well as from control tissue. Compared to fiber-high samples, IEC purified from fiber-low rectosigmoid expressed significantly higher levels of IL-8 but not TNF-α, IL-10, TGF-ß1, Muc-2 or tight junction proteins. IEC from fiber-low rectosigmoid showed higher IL-8 protein concentrations in cell lysates as well as prominent IL-8 immunoreactivity compared to IEC from fiber-high tissue. Using the human colonic IEC cell line SW480 we demonstrated that cholinergic signals suppress lipopolysaccharide-induced IL-8 secretion via the alpha 7 nicotinic acetylcholine receptor (a7nAChR). In conclusion, we showed for the first time that the presence of a dense mucosal cholinergic innervation is associated with decreased secretion of IEC-derived pro-inflammatory IL-8 in the rectosigmoid of HSCR patients likely dependent on a7nAChR activation. Owing to the association between IL-8 and enterocolitis-prone, fiber-low HSCR patients, targeted therapies against IL-8 might be a promising immunotherapy candidate for HAEC treatment.

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.

Postnatal human enteric neurospheres show a remarkable molecular complexity.

BACKGROUND: The enteric nervous system (ENS), a complex network of neurons and glial cells, coordinates major gastrointestinal functions. Impaired development or secondary aberrations cause severe enteric neuropathies. Neural crest-derived stem cells as well as enteric neuronal progenitor cells, which form enteric neurospheres, represent a promising tool to unravel molecular pathomechanisms and to develop novel therapy options. However, so far little is known about the detailed cellular composition and the proportional distribution of enteric neurospheres. Comprehensive knowledge will not only be essential for basic research but also for prospective cell replacement therapies to restore or to improve enteric neuronal dysfunction. METHODS: Human enteric neurospheres were generated from three individuals with varying age. For detailed molecular characterization, nCounter target gene expression analyses focusing on stem, progenitor, neuronal, glial, muscular, and epithelial cell markers were performed. Corresponding archived paraffin-embedded individuals' specimens were analyzed accordingly. KEY RESULTS: Our data revealed a remarkable molecular complexity of enteric neurospheres and archived specimens. Amongst the expression of multipotent stem cell, progenitor cell, neuronal, glial, muscle and epithelial cell markers, moderate levels for the pluripotency marker POU5F1 were observed. Furthermore, besides the interindividual variability, we identified highly distinct intraindividual expression profiles. CONCLUSIONS & INFERENCES: Our results emphasize the assessment of molecular signatures to be essential for standardized use, optimization of experimental approaches, and elimination of potential risk factors, as the formation of tumors. Our study pipeline may serve as a blueprint implemented into the characterization procedure of enteric neurospheres for various future applications.

Peritoneal Dialysis Vintage and Glucose Exposure but Not Peritonitis Episodes Drive Peritoneal Membrane Transformation During the First Years of PD.

The impact of peritoneal dialysis (PD) associated peritonitis on peritoneal membrane integrity is incompletely understood. Children are particularly suited to address this question, since they are largely devoid of preexisting tissue damage and life-style related alterations. Within the International Peritoneal Biobank, 85 standardized parietal peritoneal tissue samples were obtained from 82 children on neutral pH PD fluids with low glucose degradation product (GDP) content. 37 patients had a history of peritonitis and 16 of the 37 had two or more episodes. Time interval between tissue sampling and the last peritonitis episode was 9 (4, 36) weeks. Tissue specimen underwent digital imaging and molecular analyses. Patients with and without peritonitis were on PD for 21.0 (12.0, 36.0) and 12.8 (7.3, 27.0) months (p = 0.053), respectively. They did not differ in anthropometric or histomorphometric parameters [mesothelial coverage, submesothelial fibrosis, blood, and lymphatic vascularization, leukocyte, macrophage and activated fibroblast counts, epithelial-mesenchymal transition (EMT), podoplanin positivity and vasculopathy]. VEGF and TGF-ß induced pSMAD abundance were similar. Similar findings were also obtained after matching for age and PD vintage and a subgroup analysis according to time since last peritonitis (<3, <6, >6 months). In patients with more than 24 months of PD vintage, submesothelial thickness, vessel number per mmm section length and ASMA fibroblast positivity were higher in patients with peritonitis history; only the difference in ASMA positivity persisted in multivariable analyses. While PD duration and EMT were independently associated with submesothelial thickness, and glucose exposure and EMT with peritoneal vessel density in the combined groups, submesothelial thickness was independently associated with EMT in the peritonitis free patients, and with duration of PD in patients with previous peritonitis. This detailed analysis of the peritoneal membrane in pediatric patients on PD with neutral pH, low GDP fluids, does not support the notion of a consistent long-term impact of peritonitis episodes on peritoneal membrane ultrastructure, on inflammatory and fibrotic cell activity and EMT. Peritoneal alterations are mainly driven by PD duration, dialytic glucose exposure, and associated EMT.

Neutral pH and low-glucose degradation product dialysis fluids induce major early alterations of the peritoneal membrane in children on peritoneal dialysis.

The effect of peritoneal dialysates with low-glucose degradation products on peritoneal membrane morphology is largely unknown, with functional relevancy predominantly derived from experimental studies. To investigate this, we performed automated quantitative histomorphometry and molecular analyses on 256 standardized peritoneal and 172 omental specimens from 56 children with normal renal function, 90 children with end-stage kidney disease at time of catheter insertion, and 82 children undergoing peritoneal dialysis using dialysates with low-glucose degradation products. Follow-up biopsies were obtained from 24 children after a median peritoneal dialysis of 13 months. Prior to dialysis, mild parietal peritoneal inflammation, epithelial-mesenchymal transition and vasculopathy were present. After up to six and 12 months of peritoneal dialysis, blood microvessel density was 110 and 93% higher, endothelial surface area per peritoneal volume 137 and 95% greater, and submesothelial thickness 23 and 58% greater, respectively. Subsequent peritoneal changes were less pronounced. Mesothelial cell coverage was lower and vasculopathy advanced, whereas lymphatic vessel density was unchanged. Morphological changes were accompanied by early fibroblast activation, leukocyte and macrophage infiltration, diffuse podoplanin presence, epithelial mesenchymal transdifferentiation, and by increased proangiogenic and profibrotic cytokine abundance. These transformative changes were confirmed by intraindividual comparisons. Peritoneal microvascular density correlated with peritoneal small-molecular transport function by uni- and multivariate analysis. Thus, in children on peritoneal dialysis neutral pH dialysates containing low-glucose degradation products induce early peritoneal inflammation, fibroblast activation, epithelial-mesenchymal transition and marked angiogenesis, which determines the PD membrane transport function.

Skills in minimally invasive and open surgery show limited transferability to robotic surgery: results from a prospective study.

BACKGROUND: There is limited evidence on the transferability of conventional laparoscopic and open surgical skills to robotic-assisted surgery. The primary aim of this study was to evaluate the transferability of expertise in conventional laparoscopy and open surgery to robotic-assisted surgery using the da Vinci Skills Simulator (dVSS). Secondary aims included evaluating the influence of individual participants' characteristics. METHODS: Participants performed four tasks on the dVSS: Peg Board 1 (PB), Pick and Place (PP), Thread the Rings (TR), and Suture Sponge 1 (SS). Participants were classified into three groups (Novice, Intermediate, Experts) according to experience in laparoscopic and open surgery. All tasks were performed twice except for SS. Performance was assessed using the built-in scoring system. RESULTS: 37 medical students and 25 surgeons participated. Experts did not perform significantly better than less experienced participants on the dVSS. Specifically, with regard to laparoscopic experience, total simulator scores were: Novices 68.2 ± 28.8; Intermediates 65.1 ± 31.2; Experts 65.1 ± 30.0; p = 0.611. Regarding open surgical experience, scores were: Novices 68.6 ± 28.7; Intermediates 68.2 ± 30.8; Experts 63.2 ± 30.3; p = 0.305. Although there were some significant differences among groups for single parameters in specific tasks, there was no constant superiority of one group. Laparoscopic and open surgical Novices improved significantly in overall score and time for all three tasks (p < 0.05). Laparoscopic intermediates improved only in PP time (4.64 ± 3.42; p = 0.006), open Intermediates in PB score (11.98 ± 13.01; p = 0.025), and open Experts in PP score (6.69 ± 11.48; p = 0.048). Laparoscopic experts showed no improvement. Participants with gaming experience had better overall scores than non-gamers when comparing all second attempts (Gamer 83.62 ± 7.57; Non-Gamer 76.31 ± 12.78; p = 0.008) as well as first and second attempts together (Gamer 72.08 ± 8.86; Non-Gamer 65.45 ± 11.68; p = 0.039). Musical and sports experience showed no correlation with robotic performance. CONCLUSIONS: Robotic-assisted surgery requires skills distinct from conventional laparoscopy or open surgery. Basic robotic skills training prior to patient contact should be required.

Halsted's "See One, Do One, and Teach One" versus Peyton's Four-Step Approach: A Randomized Trial for Training of Laparoscopic Suturing and Knot Tying.

BACKGROUND: This study aimed to compare the effectiveness of Halsted's method "see one, do one, and teach one" with Peyton's Four-Step Approach for teaching intracorporal suturing and knot tying (ICKT). METHODS: Laparoscopically naïve medical students (n = 60) were randomized to teaching of ICKT with either Halsted's (n = 30) or Peyton's method (n = 30) for 60 minutes. Each student's first 3 and final sutures were evaluated using Objective Structured Assessment of Technical Skills (OSATS), procedural implementation, knot quality, total time, and suture placement accuracy. RESULTS: Performance score and OSATS-PSC always differed significantly in favor of Peyton's group (p = 0.001). OSATS-GRS (p = 0.01) and task time (p = 0.03) differed only in the summary of the first 3 sutures in favor of Peyton's group. There were no significant intergroup differences in knot quality and accuracy. CONCLUSIONS: Peyton's Four-Step Approach is the preferable method for learning complex laparoscopic skills like ICKT.

[New Approaches for Young Surgeons - Students' Symposium on Minimally Invasive Surgery]. / Neue Wege zum chirurgischen Nachwuchs ­ Studierendenforum für Minimal Invasive Chirurgie.

Background Physician shortage is particularly striking in surgical specialities. Umbrella organisations are making an effort to recruit medical students. Students' symposia during congresses seem to provide a promising approach to developing motivation and promoting interest. An exemplary students' symposium took place at the three nations meeting for minimally invasive surgery (MIS). Our aim was to evaluate the students' symposium from the students' perspective, in order to give recommendations for the future. Methods Of a total of 60 participants, half (30/60) completed the survey. Using a 5-point Likert scale, students evaluated items on the agenda, increase in interests, personal benefit and likelihood of future participation. Results Sixty percent (18/30) of the participants in the student forum reported enhanced interest in MIC - the largest increase found. For surgery in general and for robotic surgery in particular, an increase was reported by 57% (17/30) of the students. Of all the items on the agenda, laparoscopic hands-on experience was rated best - with a positive rating from 90% (27/30) of the students. Students expressed the wish for improved personal exchange with experts and professionals. Two thirds (40/60) of the students stated that future participation was definite or very likely. Discussion The increase in interest in MIS and surgery in general demonstrated the success of the students' symposium. Hands-on experiences was very popular. Future events should focus on personal exchange between students and experts. This seems necessary to reduce prejudice in the debate on a well-adjusted work-life balance. With a view to physician shortage in surgical specialties, students' symposia are a valuable option that should be firmly established and consistently developed.

Intracorporal knot tying techniques - which is the right one?

INTRODUCTION: Intracorporal knot tying (ICKT) and suturing in minimal invasive surgery (MIS) represent a key skill for advanced procedures such as Nissen fundoplication. Suture placement under tension is particularly challenging during MIS. The aim of this study was to compare ICKT of the common surgical square knot and the slipping knot on a simulated suture placement under tension. Furthermore, we objectively assessed the surgical skill of ICKT following 3hours of hands-on training. METHODS: A box trainer was used for laparoscopic knot tying with predefined openings. A 12cm suture was placed in central view. We used a standardized silicon suture pad with a defined wound dehiscence of 0.5cm and marked needle entrance and exit targets next to the incision. Twenty participants were divided among three groups in this study. The first group (n=5) consisted of senior physicians. The second group (n=5) was made up of surgical residents in the first to fourth year of residency training. The third group (n=10) contained medical students between their third and sixth year of study without any prior experience in laparoscopic surgery. Residents and students received a 3-hour hands-on training in surgical square and slipping knot tying. Each participant tied two of each knot types before and after the hands-on training. Knot quality, performance, total time and suture placement accuracy were the parameters for assessment in this study. RESULTS: The knot quality was greater for the slipping knot compared with the square knot in all groups. There were no significant intragroup differences in knot tying performance, task time and accuracy of both suture methods. Students and residents improved in all categories for both ICKT techniques after training. DISCUSSION: We compared ICKT of the surgical square knot with the slipping knot on a simulated suture placement under tension during a standardized training program for medical students and surgical residents. In our study, the average quality of the slipping knot was significantly superior to the square knot in all participants. The knot tying performance, task time, and accuracy of students and residents after hands-on training were not significantly different between both suture methods. This suggests that the two ICKT techniques have similar properties except the quality advantages of the slipping knot. Although students and residents improved in all categories for both ICKT techniques after training, they did not achieve expert level for task times and accuracy. CONCLUSIONS: In this pilot trail, the quality of the slipping knot was superior to the surgical square knot during intracorporal suturing under tension. Our 3-hour sequential training program improved laparoscopic suturing and knot tying skills in all participants. Our findings suggest that training centers for MIS using validated training programs should be a continuous and integral part of surgical education. LEVEL OF EVIDENCE: USPSTF Level III: monocentric, prospective, pilot Trial.

Sequential learning of psychomotor and visuospatial skills for laparoscopic suturing and knot tying-a randomized controlled trial "The Shoebox Study" DRKS00008668.

PURPOSE: Learning curves for minimally invasive surgery are prolonged since psychomotor skills and visuospatial orientation differ from open surgery and must be learned. This study explored potential advantages of sequential learning of psychomotor and visuospatial skills for laparoscopic suturing and knot tying compared to simultaneous learning. METHODS: Laparoscopy-naïve medical students were randomized into a sequential learning group (SEQ) or a simultaneous learning group (SIM). SEQ (n = 28) trained on a shoebox with direct 3D view before proceeding on a box trainer with 2D laparoscopic view. SIM (n = 25) trained solely on a box trainer with 2D laparoscopic view. Training time and number of attempts needed were recorded until a clearly defined proficiency level was reached. RESULTS: Groups were not different in total training time (SEQ 5868.7 ± 2857.2 s; SIM 5647.1 ± 2244.8 s; p = 0.754) and number of attempts to achieve proficiency in their training (SEQ 44.0 ± 17.7; SIM 36.8 ± 15.6; p = 0.123). SEQ needed less training time on the box trainer with 2D laparoscopic view than did SIM (SEQ 4170.9 ± 2350.8 s; SIM 5647.1 ± 2244.8 s; p = 0.024), while the number of attempts here was not different (SEQ 29.9 ± 14.1; SIM 36.8 ± 15.6; p = 0.097). SEQ was faster in the first attempts on the shoebox (281.9 ± 113.1 s) and box trainer (270.4 ± 133.1 s) compared to the first attempt of SIM on the box trainer (579.4 ± 323.8 s) (p < 0.001). CONCLUSION: In the present study, SEQ was faster than SIM at the beginning of the learning curve. SEQ did not reduce the total training time needed to reach an ambitious proficiency level. However, SEQ needed less training on the box trainer; thus, laparoscopic experience can be gained to a certain extent with a simple shoebox.

Sequential learning of psychomotor and visuospatial skills for laparoscopic suturing and knot tying - study protocol for a randomized controlled trial "The shoebox study".

BACKGROUND: Laparoscopy training has become an integral part of surgical education. Suturing and knot tying is a basic, yet inherent part of many laparoscopic operations, and should be mastered prior to operating on patients. One common and standardized suturing technique is the C-loop technique. In the standard training setting, on a box trainer, the trainee learns the psychomotor movements of the task and the laparoscopic visuospatial orientation simultaneously. Learning the psychomotor and visuospatial skills separately and sequentially may offer a more time-efficient alternative to the current standard of training. METHODS: This is a monocentric, two-arm randomized controlled trial. The participants are medical students in their clinical years (third to sixth year) at Heidelberg University who have not previously partaken in a laparoscopic training course lasting more than 2 hours. A total of 54 students are randomized into one of two arms in a 1:1 ratio to sequential learning (group 1) or control (group 2). Both groups receive a standardized introduction to the training center, laparoscopic instruments, and C-loop technique. Group 1 learn the C-loop using a transparent shoebox, thus only learning the psychomotor skills. Once they reach proficiency, they then perform the same knot tying procedure on a box trainer with standard laparoscopic view, where they combine their psychomotor skills with the visuospatial orientation inherent to laparoscopy. Group 2 learn the C-loop using solely a box trainer with standard laparoscopic view until they reach proficiency. Trainees work in pairs and time is recorded for each attempt. The primary outcome is mean total training time for each group. Secondary endpoints include procedural and knot quality subscore differences. Tertiary endpoints include studying the influence of gender and video game experience on performance. DISCUSSION: This study addresses whether the learning of the psychomotor and visuospatial aspects of laparoscopic suturing and knot tying is optimal sequentially or simultaneously, by assessing total training time, procedural, and knot quality differences between the two groups. It will improve the efficiency of future laparoscopic suturing courses and may serve as an indicator for laparoscopic training in a broader context, i.e., not only for suturing and knot tying. TRIAL REGISTRATION: This trial was registered on 12 August 2015 with the trial registration number DRKS00008668 .

Contrast Enema for Hirschsprung Disease Investigation: Diagnostic Accuracy and Validity for Subsequent Diagnostic and Surgical Planning.

INTRODUCTION: A targeted Hirschsprung disease (HD) diagnostic is necessary, as it determines a specific approach primarily based on surgical resection of the affected aganglionic colonic segment. The aim of this study was to evaluate the diagnostic accuracy of a contrast enema (CE) for HD diagnosis and to determine whether it should be performed before or after rectal biopsies (RBs). METHODS: A retrospective observational study of children undergoing RB for HD investigation was performed. In the performed CE, the occurrence and the level of a colonic caliber change (CCC) were recorded and its concordance with the histologically assessed level of aganglionosis by RB and the odds ratio were calculated. RESULTS: A total of 107 cases were included. Sensitivity and specificity for a CCC in CE were 74.1% and 94.6%. A CCC present in CE was associated with a 50-fold increased probability for a histologically proven HD. The overall concordance between a CCC and the histologically assessed level of aganglionosis was high (kappa 0.642, p = 0.003), being correct in 94.4% of cases when the CCC was located in the rectosigmoid, but only in 50% of cases when it was located in more proximal segments. By performing a CE only after HD diagnosis confirmation by RB would avoid 67.5% of CE with no loss of diagnostic accuracy. CONCLUSION: We confirm that CE is a valuable tool for HD diagnosis; however, it should only be performed for subsequent diagnostic and surgical planning following histological confirmation of HD by RB. On the basis of this, an algorithm for an optimized investigation and management of HD is presented.

No association between the common calcium-sensing receptor polymorphism rs1801725 and irritable bowel syndrome.

BACKGROUND: The calcium-sensing receptor (CaSR) is a calcium (Ca(2+)) sensitive G protein-coupled receptor implicated in various biological processes. In particular, it regulates Ca(2+)/Mg(2+)- homeostasis and senses interstitial Ca(2+) levels and thereby controls downstream signalling cascades. Due to its expression in the gut epithelium, the enteric nervous system and smooth muscles and its key function in regulation and coordination of muscular contraction and secretion, it represents an excellent candidate gene to be investigated in the pathophysiology of irritable bowel syndrome (IBS). Disturbed CaSR structure and function may impact gastrointestinal regulation of muscular contraction, neuronal excitation and secretion and consequently contribute to symptoms seen in IBS, such as disordered defecation as well as disturbed gut motility and visceral sensitivity. METHODS: We have therefore genotyped the functional CASR SNP rs1801725 in three case control samples from the UK, Belgium and the USA. RESULTS: Genotype frequencies showed no association in the three genotyped case-control samples, neither with IBS nor with IBS subtypes. CONCLUSIONS: Although we could not associate the SNP to any of the established bowel symptom based IBS subtypes we cannot rule out association to altered Ca(2+) levels and disturbed secretion and gut motility which were unfortunately not assessed in the patients genotyped. This underlines the necessity of a more detailed phenotyping of IBS patients and control individuals in future studies.