Editorial for the Special Issue "Current Development of Pediatric Minimally Invasive Surgery" of the Journal Children.

Dear colleagues, [...].

Mobile Dressing Trolleys Improve Satisfaction and Logistics on Pediatric Surgery Wards.

BACKGROUND: Evidence-based data on the effect of dressing trolleys on children's postoperative recovery are not available. The aim of this study was to evaluate a specific pediatric surgical dressing trolley on patient and caregiver satisfaction, as well as temporal and logistical aspects of the dressing change procedures. METHODS: In a prospective observational non-randomized study, a total of 100 dressing changes were observed before (group 1) and after (group 2) the introduction of a pediatric surgical dressing trolley and the satisfaction, time and logistical factors were recorded on site. RESULTS: The median preparation time, the duration of the dressing change and the total time decreased significantly from group 1 to group 2 by 1:11 min (p < 0.001); 1:56 min (p = 0.05) and 5:09 min (p = 0.001), respectively. The patient's room was left significantly less often in group 2 to retrieve missing bandages. The median satisfaction of the medical staff increased by 12% in group 2 (p < 0.001). The satisfaction of the parents increased by 2.5% in group 2 (p = 0.042), and that of the nursing staff increased by 9.25% in group 2 (p = 0.015). CONCLUSIONS: Our results demonstrate the positive effects of a dressing trolley for pediatric surgical dressing changes by minimizing postoperative handling and manipulation of the child. It improves time and logistical factors as well as the satisfaction of those involved, which may lead to a faster recovery.

Evaluation of the Versius Robotic System for Infant Surgery-A Study in Piglets of Less than 10 kg Body Weight.

BACKGROUND: We were able to demonstrate the feasibility of a new robotic system (Versius, CMR Surgical, Cambridge, UK) for procedures in small inanimate cavities. The aim of this consecutive study was to test the Versius® system for its feasibility, performance, and safety of robotic abdominal and thoracic surgery in piglets simulating infants with a body weight lower than 10 kg. METHODS: A total of 24 procedures (from explorative laparoscopy to thoracoscopic esophageal repair) were performed in 4 piglets with a mean age of 12 days and a mean body weight of 6.4 (7-7.5) kg. Additional urological procedures were performed after euthanasia of the piglet. The Versius® robotic system was used with 5 mm wristed instruments and a 10 mm 3D 0° or 30° camera. The setup consisted of the master console and three to four separate arms. The performance of the procedure, the size, position, and the distance between the ports, the external and internal collisions, and complications of the procedures were recorded and analyzed. RESULTS: We were able to perform all surgical procedures as planned. We encountered neither surgical nor robot-associated complications in the live model. Whereas all abdominal procedures could be performed successfully under general anesthesia, one piglet was euthanized early before the thoracic interventions, likely due to pulmonary inflammatory response. Technical limitations were based on the size of the camera (10 mm) being too large and the minimal insertion depth of the instruments for calibration of the fulcrum point. CONCLUSIONS: Robotic surgery on newborns and infants appears technically feasible with the Versius® system. Software adjustments for fulcrum point calibration need to be implemented by the manufacturer as a result of our study. To further evaluate the Versius® system, prospective trials are needed, comparing it to open and laparoscopic surgery as well as to other robotic systems.

Minimally Invasive Bimanual Fetal Surgery-A Review.

BACKGROUND: The aim of this review is to discuss experimental and clinical techniques and interventions of fetal surgery which have been performed minimally invasively by the means of a three-port approach for the fetoscope and instruments for the left and right hand of the surgeon (bimanual minimally invasive fetal surgery). METHODS: a print and electronic literature search was performed; the titles and abstracts were screened and included reports were reviewed in a two-step approach. First, reports other than minimally invasive fetal surgery were excluded, then a full text review and analysis of the reported data was performed. RESULTS: 17 reports were included. The heterogeneity of the included reports was high. Although reports on human fetoscopic surgical procedures can be found, most of them do not pick out bimanual fetal surgery as a central theme but rather address interventions applying a fetoscope with a working channel for a laser fiber, needle or flexible instrument. Most reports were on experimentation in animal models, the human application of minimally invasive fetoscopic bimanual surgery is rare and has at best been explored for the prenatal treatment of spina bifida. Some reported bimanual fetoscopic procedures were performed on the exteriorized uterus via a maternal laparotomy and can therefore not be classified as being truly minimally invasive. DISCUSSION: our results demonstrate that minimally invasive fetoscopic bimanual surgery is rare, even in animal models, excluding many other techniques and procedures that are loosely termed 'minimally invasive fetal surgery' which we suggest to better label as 'interventions'. Thus, more research on percutaneous minimally invasive bimanual fetoscopic surgery is warranted, with the aim to reduce the maternal, uterine and fetal trauma for correction of congenital malformations.

Robot-assisted scaffold implantation and two-stage flap raising of the greater omentum for reconstruction of the facial skeleton: Description of a novel technique.

BACKGROUND: Bone regeneration in the greater omentum is a promising strategy in facial skeleton reconstruction. This feasibility-study aims to perform robot-assisted scaffold implantation and second-stage flap raising. METHODS: Firstly, scaffolds were implanted into the greater omentum using the da Vinci Xi surgical system or conventional technique in five miniature pigs, respectively. After 3 months a free flap including the gastrocolic vascular pedicle was harvested and procedures were evaluated. RESULTS: The average operation time was 59.2 min for open surgery and 73.8 min for robot-assisted surgery. The average incision length of open surgery was 11.6 cm. Both techniques led to successful scaffold implantation without any complication. In all cases the scaffolds were integrated as intended and resulted in bone formation. CONCLUSIONS: Current study demonstrated that the implantation of scaffolds into the greater omentum and flap harvesting using da Vinci Xi surgical system is a promising minimally-invasive approach in regenerative surgery.

Fetal Surgery for Gastroschisis-A Review with Emphasis on Minimally Invasive Procedures.

(1) Background: The morbidity of gastroschisis is defined by exposure of unprotected intestines to the amniotic fluid leading to inflammatory damage and consecutive intestinal dysmotility, the viscero-abdominal disproportion which results in an abdomen too small to incorporate the herniated and often swollen intestine, and by associated pathologies, such as in complex gastroschisis. To prevent intestinal damage and to provide for growth of the abdominal cavity, fetal interventions such as amnio exchange, gastroschisis repair or covering have been evaluated in several animal models and human trials. This review aims to evaluate the reported techniques for the fetal treatment of gastroschisis by focusing on minimally invasive procedures. (2) Methods: We conducted a systematic database search, quality assessment and analyzed relevant articles which evaluate or describe surgical techniques for the prenatal surgical management of gastroschisis in animal models or human application. (3) Results: Of 96 identified reports, 42 eligible studies were included. Fetal interventions for gastroschisis in humans are only reported for EXIT procedures and amnio exchange. In animal models, particularly in the fetal sheep model, several techniques of open or minimally invasive repair of gastroschisis or covering the intestine have been described, with fetoscopic covering being the most encouraging. (4) Discussion: Although some promising minimally invasive techniques have been demonstrated in human application and animal models, most of them are still associated with relevant fetal morbidity and mortality and barely appear to be currently applicable in humans. Further research on specific procedures, instruments and materials is needed before any human application.

Evaluation of the Versius Robotic Surgical System for Procedures in Small Cavities.

BACKGROUND: The Versius® is a recently approved robotic surgical system for general surgery procedures in adults. Before any application in children, data of its feasibility and safety in small cavities has to be compiled, beginning with inanimate models. Therefore, the aim of this preclinical study was to assess the Versius® system for its performance in small boxes simulating small body cavities. METHODS: In total, 8 cardboard boxes of decreasing volumes (15.75 L to 106 mL) were used. The procedures, two single stitches with two square knots each, were performed in every box, starting in the largest and consecutively exchanging the box to the next smaller one. The evaluation included procedure time, port placement and pivot point setup, arrangement of the robotic arms and instrumentation, amount of internal and external instrument-instrument collisions and instrument-box collisions. RESULTS: All procedures could be successfully performed in all boxes. The procedure time decreased due to the learning curve in the first four boxes (15.75 to 1.87 L) and consecutively increased from boxes of 1.22 L up to the smallest box with the dimensions of 4.4 × 4.9 × 4.9 cm3. This may be based on the progress of complexity of the procedures in small cavities, which is also depicted by the synchronous increase of the internal instrument-instrument and instrument-box collisions. CONCLUSION: With the use of the Versius® robotic surgical system, we were able to perform robotic reconstructive procedures, such as intracorporal suturing and knot tying, in cavities as small as 106 mL. Whether this system is comparable or even superior to conventional laparoscopic surgery in small cavities, such as in children, has to be evaluated. Furthermore, before any application in newborns or infants, ongoing evaluation of this system should be performed in a live animal model.

Robotic infant surgery with 3 mm instruments: a study in piglets of less than 10 kg body weight.

No data exist concerning the appication of a new robotic system with 3 mm instruments (Senhance®, Transenterix) in infants and small children. Therefore, the aim of this study was to test the system for its feasibility, performance and safety of robotic pediatric abdominal and thoracic surgery in piglets simulating infants with a body weight lower than 10 kg. 34 procedures (from explorative laparoscopy to thoracoscopic esophageal repair) were performed in 12 piglets with a median age of 23 (interquartile range: 12-28) days and a median body weight of 6.9 (6.1-7.3) kg. The Senhance® robotic system was used with 3 mm instruments, a 10 mm 3D 0° or 30° videoscope and advanced energy devices, the setup consisted of the master console and three separate arms. The amount, size, and position of the applied ports, their distance as well as the distance between the three operator arms of the robot, external and internal collisions, and complications of the procedures were recorded and analyzed. We were able to perform all planned surgical procedures with 3 mm robotic instruments in piglets with a median body weight of less than 7 kg. We encountered two non-robot associated complications (bleeding from the inferior caval and hepatic vein) which led to termination of the live procedures. Technical limitations were the reaction time and speed of robotic camera movement with eye tracking, the excessive bending of the 3 mm instruments and intermittent need of re-calibration of the fulcrum point. Robotic newborn and infant surgery appears technically feasible with the Senhance® system. Software adjustments for camera movement and sensitivity of the fulcrum point calibration algorithm to adjust for the increased compliance of the abdominal wall of infants, therefore reducing the bending of the instruments, need to be implemented by the manufacturer as a result of our study. To further evaluate the Senhance® system, prospective trials comparing it to open, laparoscopic and other robotic systems are needed.

Preputioplasty as a surgical alternative in treatment of phimosis.

Preputioplasty denotes various surgical techniques directed at resolving phimosis without the need for radical or partial circumcision. This narrative review summarizes the best-known surgical techniques of preputioplasty. A MEDLINE and EMBASE-based literature search of original manuscripts and case reports published in English has been carried out using the following key words: "circumcision", "partial circumcision", "phimosis", "paraphimosis", and "preputioplasty". Six different procedures are explored in more detail and illustrated. The complication rates of all surgical procedures presented here are reported to be low. In cases of medical (rather than cultural and religious) indications, foreskin-preserving procedures present useful alternatives to circumcision in the routine clinical practice of urologists and pediatric surgeons.

Stereological Lung Parameters After Fetoscopic Abdominal Decompression of Congenital Diaphragmatic Hernia in an Ovine Model: A Pilot Study.

Background: Fetoscopic endoluminal tracheal occlusion (FETO) improves lung maturation in severe cases of congenital diaphragmatic hernia (CDH) but it does not ameliorate lung compression by herniated abdominal organs. Surgically opening the fetal abdomen (abdominal decompression [AD]) reduces the intrathoracic pressure by diverting the abdominal organs into the amniotic cavity-a probable causal therapy for lung hypoplasia and pulmonary hypertension in CDH. Open surgical abdominal decompression has been reported: we describe a minimally invasive approach in an ovine model of CDH as a probable fetoscopic intervention. Materials and Methods: Eight fetuses were included, 2 were kept as HEALTHY controls. A CDH (left side, liver down) was created by open fetal surgery at midgestation in 6 fetuses, 2 were taken as CDH controls. Fetoscopic abdominal decompression (fAD) was performed 21 days later in 4 animals. The fetuses were retrieved at the end of gestation and evaluated by lung stereology. Results: fAD led to a near total evacuation of the thoracic cavity in 2 of the 4 animals. Fetuses with CDH had a lower total volume and fraction of alveolar air space, a lower volume fraction of the parenchyma, and an increase of the volume fraction of the alveolar septa and atelectasis, as well as an increased mean thickness of alveolar septa compared with HEALTHY fetuses. Fetuses treated with abdominal decompression showed an improvement of stereological parameters. Conclusions: In spite of relevant limitations (pilot study, small groups, spontaneous closure of the abdominal incision) we were able to demonstrate that abdominal decompression for CDH can be performed by fetoscopy. Our results support the hypothesis of causally improving lung development by abdominal decompression, thus implying increased survival in extreme cases of CDH. A refinement of the fetoscopic techniques and direct comparison to FETO appears warranted.

Fetoscopic techniques for prenatal covering of gastroschisis in an ovine model are technically demanding and do not lead to permanent anchoring on the fetus until the end of gestation.

INTRODUCTION: This is the cumulative technical report on the operative procedures and limitations of fetoscopic bag insertion, intestinal bag placement, and bag fixation to the fetus in a series of pilot studies in an ovine model for prenatal treatment of gastroschisis. MATERIAL AND METHODS: In 24 German blackhead sheep, a surgically created gastroschisis was managed by fetoscopic placement of the extruded intestines into a bag. The bag was then fastened onto the fetal abdominal wall. Different materials (sterile gloves, latex condoms, laparosopic retrieval bags) and different fixation techniques (laparoscopic staplers, interrupted and continuous sutures) have been examined. The fetuses were retrieved and evaluated at the end of gestation. RESULTS: Uterine bag insertion was successful in 15 of 24 (62.5%) and intestinal bag placement in 10 of 15 available fetuses (66.6%). The main factor limiting fetoscopic procedures was chorioamniotic separation (CAS). Sterilized condoms provided the most appropriate type of bags and the V-Loc™ running suture, the most expedient type of fixation, which was achieved in 9 of the 10 fetuses (complete = 2, partially = 7) by using a three port access (5 mm and 2 × 3 mm). All bags were encountered completely or partially dislocated from the fetus at the end of gestation. CONCLUSIONS: Fetoscopic intestinal bag placement and fixation in gastroschisis technically demanding. None of the evaluated techniques led to permanent anchorage of the bag to the fetus. The development of specially designed instruments, bags and fixation methods is required to optimize this approach.

Advances and Trends in Pediatric Minimally Invasive Surgery.

As many meta-analyses comparing pediatric minimally invasive to open surgery can be found in the literature, the aim of this review is to summarize the current state of minimally invasive pediatric surgery and specifically focus on the trends and developments which we expect in the upcoming years. Print and electronic databases were systematically searched for specific keywords, and cross-link searches with references found in the literature were added. Full-text articles were obtained, and eligibility criteria were applied independently. Pediatric minimally invasive surgery is a wide field, ranging from minimally invasive fetal surgery over microlaparoscopy in newborns to robotic surgery in adolescents. New techniques and devices, like natural orifice transluminal endoscopic surgery (NOTES), single-incision and endoscopic surgery, as well as the artificial uterus as a backup for surgery in preterm fetuses, all contribute to the development of less invasive procedures for children. In spite of all promising technical developments which will definitely change the way pediatric surgeons will perform minimally invasive procedures in the upcoming years, one must bear in mind that only hard data of prospective randomized controlled and double-blind trials can validate whether these techniques and devices really improve the surgical outcome of our patients.

Classical but Not Rap Music Significantly Improves Transferability and Long-Term Acquisition of Laparoscopic Suturing Skills: A Randomized Controlled Trial.

INTRODUCTION: Acoustic distractions have been shown to increase the level of stress and workload in the operating room (OR). Noise significantly reduces surgical performance, but experienced surgeons are able to reduce the acoustic perception of their surroundings to maintain a high level of performance in complex surgical tasks. However, music has been shown to improve learning and performance of complex motor skills. The aim of this study was to evaluate the influence of music on transferability and long-term acquisition of laparoscopic suturing skills. MATERIALS AND METHODS: To evaluate the effects of music on training, subjects were asked to perform four surgeon's square knots on a bowel model within 30 minutes-prior and post 3 hours of hands-on training. To examine long-term skills, the same students were asked to perform a comparable, but more complex, task (four slip knots in a model of esophageal atresia) 6 months post initial training, as a follow-up measurement. Total time, knot stability (evaluated via tensiometer), suture accuracy, knot quality (Muresan scale), and laparoscopic performance (Munz checklist) were assessed. RESULTS: Twenty-four students were included in the study; after simple randomization, 16 were trained while exposed to music (eight to Bach and eight to Bushido) and eight with traditional methods. Seven were lost due to follow-up. Both groups had comparable baseline characteristics and significantly improved after training, in all parameters assessed in this study. Subjects that trained with classical music were superior in terms of speed (p = 0.006), knot quality (p = 0.014), and procedural performance (p = 0.034) compared with controls. CONCLUSION: Music during acquisition of complex motor skills, like laparoscopic suturing and knot tying, is superior to traditional training. Especially music considered nondisturbing significantly improved speed, knot quality, and performance. Thus, incorporation of pleasant music into surgical skills training and the OR should be considered.

Spaced Education Improves the Retention of Laparoscopic Suturing Skills: A Randomized Controlled Study.

INTRODUCTION: Spaced learning has been shown to be superior in complex motor skill acquisition like laparoscopic suturing and knot tying. By using a pre-post follow-up design, the aim of the study was to evaluate the long-term impact of implementation of the spaced learning concept in laparoscopic training. MATERIALS AND METHODS: To evaluate the effectiveness of spaced learning, subjects were asked to perform four surgeon's square knots on a bowel model within 30 minutes-prior and after 3 hours of hands-on training. To examine the long-term skills, the same students were asked to perform a comparable, but more complex, task (four slip knots in a model of esophageal atresia) 12 months later as follow-up measurement. Total time, knot stability (evaluated via tensiometer), suture accuracy, knot quality (Muresan scale), and laparoscopic performance (Munz checklist) were assessed. Moreover, motivation was accessed using Questionnaire on Current Motivation. RESULTS: Twenty students were included in the study; after simple randomization, 10 were trained using the "spaced learning" concept and 10 via traditional methods. Both groups had comparable baseline characteristics and improved after training significantly, regarding all aspects assessed in this study. Subjects that trained via spaced learning were superior in terms of speed (p = 0.021), knot quality (p = 0.008), and suture strength (p = 0.003). Additionally, spaced learning significantly decreased anxiety (p = 0.029) and probability of success (p = 0.005). CONCLUSION: The spaced learning concept is very suitable for long-term complex motor skill acquisition, like laparoscopic suturing and knot tying. It is superior to conventional training regarding speed and, most importantly, knot quality and stability, resulting in improved confidence and motivation. Thus, we strongly recommend to incorporate the spaced learning concept into training courses and surgical programs.

Evaluation of a new robotic-assisted laparoscopic surgical system for procedures in small cavities.

No data exists concerning the application of a new robotic system with 3-mm instruments (Senhance™, Transenterix, Milano, Italy) in small cavities. Therefore, the aim of this study was to test the system for its performance of intracorporal suturing in small boxes simulating small body cavities. Translucent plastic boxes of decreasing volumes (2519-90 ml) were used. The procedures (two single stitches, each with two consecutive surgical square knots) were performed by a system-experienced and three system-inexperienced surgeons in each box, starting within the largest box, consecutively exchanging the boxes into smaller ones. With this approach, the total amount of procedures performed by each surgeon increased with decreasing volume of boxes being operated in. Outcomes included port placement, time, task completion, internal and external instrument/instrument collisions and instrument/box collisions. The procedures could be performed in all boxes. The operating time decreased gradually in the first three boxes (2519-853 ml), demonstrating a learning curve. The increase of operating time from boxes of 599 ml and lower may be attributed to the increased complexity of the procedure in small cavities as in the smallest box with the dimensions of 2.9 × 6.3 × 4.9 cm. This is also reflected by the parallel increase of internal instrument-instrument collisions. With the introduction of 3-mm instruments in a new robotic surgical system, we were able to perform intracorporal suturing and knot tying in cavities as small as 90 ml. Whether this system is comparable to conventional three-port 3-mm laparoscopic surgery in small cavities-such as in pediatric surgery-has to be evaluated in further studies.

Degradation of Extracellular DNA Significantly Ameliorates Necrotizing Enterocolitis Severity in Mice.

BACKGROUND: Necrotizing enterocolitis (NEC) is one of the most devastating diseases in neonates and is characterized by high morbidity and mortality. It has been suggested that neutrophils play a crucial role in NEC pathogenesis and contribute to the hyperinflammatory reaction after bacterial colonization, which ultimately induces NEC. The aim of this study was to investigate whether dissolution of neutrophil extracellular traps (NETs) by systemic DNase1 therapy reduces NEC manifestation and morbidity. METHODS: NEC was induced in neonatal mice by gavage feeding of lipopolysaccharide mixed in Neocate, followed by hypoxia q12 h for 5d. Inactivated DNase1 and DNase1 were administered intraperitoneally twice daily in the control and treatment groups, respectively, starting on day 5 for 72 h. Survival, NEC score, intestinal damage (Chiu score, malondialdehyde [MDA], glutathione peroxidase [GPx]), inflammation (neutrophil elastase [NE], myeloperoxidase [MPO], toll-like receptor 4 [TLR4]), and NETs markers (SYTOX orange, cell-free DNA [cfDNA], DNase, citrullinated Histone 3 [H3cit]) were then assessed. RESULTS: In total, 44 neonatal mice were used in the experiment. Mice in the treatment group demonstrated significantly reduced NEC rates (44 versus 86%, P = 0.029) and improved survival in comparison to controls (65 versus 35%, P = 0.01). Furthermore, mice treated with DNase1 showed significantly less tissue damage (cfDNA, Chiu score), oxidative stress (MDA, GPx), and inflammation (NE, MPO, H3cit, TLR4), which ultimately lead to a significant reduction in mortality. CONCLUSIONS: The results of the study indicate that systemic DNase1 treatment leads to a significant reduction in tissue damage, NEC severity, and mortality. Therefore, after validation of our findings in human subjects, DNase1 treatment should be considered as a therapeutic option in neonates diagnosed with NEC.

NEC is likely a NETs dependent process and markers of NETosis are predictive of NEC in mice and humans.

Necrotizing enterocolitis (NEC) is one of the most devastating diseases affecting premature and mature infants. It is hypothesized that NEC is the result of neutrophils' active role in hyperinflammation after bacterial gut colonization, through their nuclear DNA release and formation of neutrophil extracellular traps (NETs) to combat pathogens. The aim of this study was to evaluate the importance of NETs in NEC pathogenesis, as well as to identify and validate markers of NETosis to predict NEC. NEC was induced in mice by gavage feeding of Neocate and lipopolysaccharide, followed by ten minutes of hypoxia (5% O2) q12h for five days, starting on day four postpartum (p.p.). The interrelation of NEC and neutrophils, including NETs, was assessed macroscopically (i.e. NEC score, SYTOX Orange), microscopically (i.e. Chiu score, citrullinated histone H3, neutrophil elastase), and in blood samples (i.e. cell-free DNA (cfDNA), DNase). In order to determine the exact role of NETs in NEC pathogenesis, a protein arginine deiminase (PAD) inhibition model was established (preventing NETs formation in mice) by injecting BB-Cl-amidine once daily, starting on day one p.p. Additionally, human intestinal samples of diagnostically verified NEC were analyzed. In total, 76 mice were analyzed in the experiment. Serum cfDNA correlated positively with NEC manifestation, as measured by macroscopic NEC score (r = 0.53, p = 0.001), and microscopic evaluation with Chiu score (r = 0.56, p < 0.001). Markers of neutrophil activation and NETosis were significantly increased in animals with NEC and in human samples as compared to controls. Further, prevention of NETosis by protein arginine deiminase (PAD) inhibition in mice significantly reduced mortality, tissue damage, and inflammation in mice induced with NEC. Our results suggest that the hyperinflammation observed in NEC is a NETs-dependent process, as NEC severity was significantly reduced in mice incapable of forming NETs (PAD inhibition) and markers for NEC and NETs correlated positively during the time course of NEC induction. Further, serum surrogate markers of NETosis (such as cfDNA and DNase) appear to predict NEC in neonatal mice. As findings of the mouse NEC model correlate positively with human NEC samples immunohistochemically, the hyperinflammation reaction observed in mice could potentially be applied to human NEC pathogenesis.

The spaced learning concept significantly improves training for laparoscopic suturing: a pilot randomized controlled study.

BACKGROUND: Spaced learning has been shown to be effective in various areas like traditional knowledge or motor skill acquisition. To evaluate the impact of implementation of the spaced learning concept in laparoscopic training was the aim of this study. METHODS: To evaluate the effectiveness of spaced learning, subjects were asked to perform four surgeon's square knots on a bowel model prior and post 3 h of hands-on training. All subjects were medical students and novice in laparoscopic suturing. Total time, knot stability (evaluated via tensiometer), suture accuracy, knot quality (Muresan score), and laparoscopic performance (Munz checklist) were assessed. Moreover, motivation was accessed using Questionnaire on Current Motivation. RESULTS: Twenty students were included in the study; after simple randomization, ten were trained using "spaced learning" concept and ten conservatively. Both groups had comparable baseline characteristics and improved after training significantly regarding all aspects assessed in this study. Subjects that trained via spaced learning were superior in terms of suture performance, knot quality, and suture strength. Ultimately, spaced learning significantly decreased anxiety and impression of challenge compared to controls. CONCLUSION: The spaced learning concept is very suitable for complex motor skill acquisition like laparoscopic suturing and knot tying. It significantly improves laparoscopic performance and knot quality as shown by the knot score and suture strength. Thus, we recommend to incorporate spaced learning into training courses and surgical programs.