Peter Funch-Jensen

Randomized clinical trial of virtual reality simulation for laparoscopic skills training

This study examined the impact of virtual reality (VR) surgical simulation on improvement of psychomotor skills relevant to the performance of laparoscopic cholecystectomy.

Incidence of Adenocarcinoma among Patients with Barrett's Esophagus

BACKGROUND Accurate population-based data are needed on the incidence of esophageal adenocarcinoma and high-grade dysplasia among patients with Barretts esophagus. METHODS We conducted a nationwide, population-based, cohort study involving all patients with Barretts esophagus in Denmark during the period from 1992 through 2009, using data from the Danish Pathology Registry and the Danish Cancer Registry. We determined the incidence rates (numbers of cases per 1000 person-years) of adenocarcinoma and high-grade dysplasia. As a measure of relative risk, standardized incidence ratios were calculated with the use of national cancer rates in Denmark during the study period. RESULTS We identified 11,028 patients with Barretts esophagus and analyzed their data for a median of 5.2 years. Within the first year after the index endoscopy, 131 new cases of adenocarcinoma were diagnosed. During subsequent years, 66 new adenocarcinomas were detected, yielding an incidence rate for adenocarcinoma of 1.2 cases per 1000 person-years (95% confidence interval [CI], 0.9 to 1.5). As compared with the risk in the general population, the relative risk of adenocarcinoma among patients with Barretts esophagus was 11.3 (95% CI, 8.8 to 14.4). The annual risk of esophageal adenocarcinoma was 0.12% (95% CI, 0.09 to 0.15). Detection of low-grade dysplasia on the index endoscopy was associated with an incidence rate for adenocarcinoma of 5.1 cases per 1000 person-years. In contrast, the incidence rate among patients without dysplasia was 1.0 case per 1000 person-years. Risk estimates for patients with high-grade dysplasia were slightly higher. CONCLUSIONS Barretts esophagus is a strong risk factor for esophageal adenocarcinoma, but the absolute annual risk, 0.12%, is much lower than the assumed risk of 0.5%, which is the basis for current surveillance guidelines. Data from the current study call into question the rationale for ongoing surveillance in patients who have Barretts esophagus without dysplasia. (Funded by the Clinical Institute, University of Aarhus, Aarhus, Denmark.).

Learning curves and impact of previous operative experience on performance on a virtual reality simulator to test laparoscopic surgical skills

BACKGROUND The study was carried out to analyze the learning rate for laparoscopic skills on a virtual reality training system and to establish whether the simulator was able to differentiate between surgeons with different laparoscopic experience. METHODS Forty-one surgeons were divided into three groups according to their experience in laparoscopic surgery: masters (group 1, performed more than 100 cholecystectomies), intermediates (group 2, between 15 and 80 cholecystectomies), and beginners (group 3, fewer than 10 cholecystectomies) were included in the study. The participants were tested on the Minimally Invasive Surgical Trainer-Virtual Reality (MIST-VR) 10 consecutive times within a 1-month period. Assessment of laparoscopic skills included time, errors, and economy of hand movement, measured by the simulator. RESULTS The learning curves regarding time reached plateau after the second repetition for group 1, the fifth repetition for group 2, and the seventh repetition for group 3 (Friedmans tests P <0.05). Experienced surgeons did not improve their error or economy of movement scores (Friedmans tests, P >0.2) indicating the absence of a learning curve for these parameters. Group 2 error scores reached plateau after the first repetition, and group 3 after the fifth repetition. Group 2 improved their economy of movement score up to the third repetition and group 3 up to the sixth repetition (Friedmans tests, P <0.05). Experienced surgeons (group 1) demonstrated best performance parameters, followed by group 2 and group 3 (Mann-Whitney test P <0.05). CONCLUSIONS Different learning curves existed for surgeons with different laparoscopic background. The familiarization rate on the simulator was proportional to the operative experience of the surgeons. Experienced surgeons demonstrated best laparoscopic performance on the simulator, followed by those with intermediate experience and the beginners. These differences indicate that the scoring system of MIST-VR is sensitive and specific to measuring skills relevant for laparoscopic surgery.

An Evidence-Based Virtual Reality Training Program for Novice Laparoscopic Surgeons

Objective:To develop an evidence-based virtual reality laparoscopic training curriculum for novice laparoscopic surgeons to achieve a proficient level of skill prior to participating in live cases. Summary Background Data:Technical skills for laparoscopic surgery must be acquired within a competency-based curriculum that begins in the surgical skills laboratory. Implementation of this program necessitates the definition of the validity, learning curves and proficiency criteria on the training tool. Methods:The study recruited 40 surgeons, classified into experienced (performed >100 laparoscopic cholecystectomies) or novice groups (<10 laparoscopic cholecystectomies). Ten novices and 10 experienced surgeons were tested on basic tasks, and 11 novices and 9 experienced surgeons on a procedural module for dissection of Calot triangle. Performance of the 2 groups was assessed using time, error, and economy of movement parameters. Results:All basic tasks demonstrated construct validity (Mann-Whitney U test, P < 0.05), and learning curves for novices plateaued at a median of 7 repetitions (Friedmans test, P < 0.05). Expert surgeons demonstrated a learning rate at a median of 2 repetitions (P < 0.05). Performance on the dissection module demonstrated significant differences between experts and novices (P < 0.002); learning curves for novice subjects plateaued at the fourth repetition (P < 0.05). Expert benchmark criteria were defined for validated parameters on each task. Conclusion:A competency-based training curriculum for novice laparoscopic surgeons has been defined. This can serve to ensure that junior trainees have acquired prerequisite levels of skill prior to entering the operating room, and put them directly into practice.

Laparoscopic performance after one night on call in a surgical department: prospective study

The study was carried out in a gastroenterological surgical unit at a teaching hospital. A night shift started at 3 30 pm and finished at 9 am the following day. A total sleep time of less than three hours was necessary for inclusion in the study. All 14 surgeons in training at our department— 11 men and three women—participated in the study. The median age was 34 (range 24-43) and the median time since graduation was six years (1-11 years). All trainees had similar, limited experience in laparoscopic surgery; the median number of cholecystectomies they had performed was 0 (0–5). All participants received identical pretraining on the minimally invasive surgical trainer-virtual reality (MIST-VR, Mentice Medical Simulation, Gothenburg, Sweden) by performing nine repetitions of six tasks. 1 2 The laparoscopic surgical …

Impact of hand dominance, gender, and experience with computer games on performance in virtual reality laparoscopy

Background: The impact of gender and hand dominance on operative performance may be a subject of prejudice among surgeons, reportedly leading to discrimination and lack of professional promotion. However, very little objective evidence is available yet on the matter. This study was conducted to identify factors that influence surgeons’ performance, as measured by a virtual reality computer simulator for laparoscopic surgery. Methods: This study included 25 surgical residents who had limited experience with laparoscopic surgery, having performed fewer than 10 laparoscopic cholecystectomies. The participants were registered according to their gender, hand dominance, and experience with computer games. All of the participants performed 10 repetitions of the six tasks on the Minimally Invasive Surgical Trainer—Virtual Reality (MIST-VR) within 1 month. Assessment of laparoscopic skills was based on three parameters measured by the simulator: time, errors, and economy of hand movement. Results: Differences in performance existed between the compared groups. Men completed the tasks in less time than women (p = 0.01, Mann–Whitney test), but there was no statistical difference between the genders in the number of errors and unnecessary movements. Individuals with right hand dominance performed fewer unnecessary movements (p = 0.045, Mann–Whitney test), and there was a trend toward better results in terms of time and errors among the residence with right hand dominance than among those with left dominance. Users of computer games made fewer errors than nonusers (p = 0.035, Mann–Whitney test). Conclusions: The study provides objective evidence of a difference in laparoscopic skills between surgeons differing gender, hand dominance, and computer experience. These results may influence the future development of training program for laparoscopic surgery. They also pose a challenge to individuals responsible for the selection and training of the residents.

Warm-up in a virtual reality environment improves performance in the operating room.

Objective:To assess the impact of warm-up on laparoscopic performance in the operating room (OR). Background:Implementation of simulation-based training into clinical practice remains limited despite evidence to show that the improvement in skills is transferred to the OR. The aim of this study was to evaluate the impact of a short virtual reality warm-up training program on laparoscopic performance in the OP. Methods:Sixteen Laparoscopic Cholecystectomies were performed by 8 surgeons in the OR. Participants were randomized to a group which received a preprocedure warm-up using a virtual reality simulator and no warm-up group. After the initial laparoscopic cholecystectomy all surgeons served as their own controls by performing another procedure with or without preoperative warm-up. All OR procedures were videotaped and assessed by 2 independent observers using the generic OSATS global rating scale (from 7 to 35). Results:There was significantly better surgical performance on the laparoscopic Cholecystectomy following preoperative warm-up, median 28.5 (range = 18.5–32.0) versus median 19.25 (range = 15–31.5), P = 0.042. The results demonstrated excellent reliability of the assessment tool used (Cronbachs &agr; = 0.92). Conclusion:This study showed a significant beneficial impact of warm-up on laparoscopic performance in the OP. The suggested program is short, easy to perform, and therefore realistic to implement in the daily life in a busy surgical department. This will potentially improve the procedural outcome and contribute to improved patient safety and better utilization of OR resources.

Randomised clinical trial: the efficacy of a transient receptor potential vanilloid 1 antagonist AZD1386 in human oesophageal pain

Aliment Pharmacol Ther 2011; 33: 1113–1122

Gut pain and hyperalgesia induced by capsaicin: a human experimental model.

&NA; Human experimental visceral pain models using chemical stimulation are needed for the study of visceral hyperexcitability. Our aim was to stimulate the human gut with chemical activators (capsaicin, glycerol) and measure quantitatively the induced hyperexcitability to painful mechanical gut distension. Ten otherwise healthy subjects with an ileostoma participated. Increasing volumes of capsaicin 50 &mgr;g/ml (0.25, 0.5, 0.75, 1.0, 1.5, 2.0, and 3 ml), glycerol (2.5, 5, and 10 ml) or saline (2.5, 5, and 10 ml) intermingled with sham stimuli were randomly applied to the ileum via the stomal opening at three occasions separated by a week. After each application, pain intensity, qualities, and referred pain area were assessed together with the pain threshold to distension of the proximal gut. ‘Boring’ and ‘hot’ pain were evoked in all subjects by low doses (median 0.5 ml) of capsaicin. The median pain onset, peak pain, and pain duration were 55, 85, and 420 s, respectively. Referred somatic pain developed around the stomal opening with a correlation between the pain area and pain intensity. After application of capsaicin, significant hyperalgesia was found to distension of the gut (a 28% reduction pressure in pain threshold). No significant manifestations were found after application of glycerol and saline. Application of capsaicin to the human ileum induces pain and mechanical hyperalgesia. Specific activation of nociceptors in the gut mucosa provides new possibilities to study clinical relevant visceral pain mechanisms.

Can everyone achieve proficiency with the laparoscopic technique? Learning curve patterns in technical skills acquisition

BACKGROUND The study was carried out to determine the learning curve patterns for basic laparoscopic technical skills. METHODS Thirty-seven surgical residents with limited laparoscopic experience performed 10 repetitions of 6 tasks on a virtual-reality trainer (MIST-VR) with standardized distribution of practice. Assessment was based on time, errors, and economy of motion as measured by MIST-VR. Proficiency levels were established by testing experienced laparoscopic surgeons. RESULTS Four learning curve patterns were determined. Surgeons in group 1 (5.4%) demonstrated proficiency from the beginning; group 2 (70.3%) achieved predefined expert criteria between 2 and 9 repetitions; group 3 (16.2%) demonstrated improvement but was unable to achieve proficiency within 10 repetitions. Group 4 (8.1%) underperformed and showed no tendency of skills improvement, reflecting a group of subjects who probably are unable to learn laparoscopic technique. CONCLUSIONS The results indicated that a group of subjects could not reach proficiency in the psychomotor skills relevant for laparoscopy. We believe that this is an important issue that should be addressed in future research.