Laboratory-based vascular anastomosis training: a randomized controlled trial evaluating the effects of bench model fidelity and level of training on skill acquisition

BACKGROUND: Although there is growing evidence that practice on bench model simulators can improve the acquisition of technical skill in surgery, the degree to which these models have to approximate real-world conditions (model fidelity) to optimize learning is unclear. Previous research suggests that low-fidelity models may be adequate for novice learners. The purpose of this study was to assess the effect of model fidelity and surgical expertise on the acquisition of vascular anastomosis skill. METHODS: Twenty-seven surgical residents participated in this institutional review board-approved study. Junior residents (postgraduate year 1 and 2) and senior residents (postgraduate year 4 or higher) were randomized into two groups: low-fidelity (n = 13) and high-fidelity (n = 14) model training. Both groups were given a 3-hour hands-on training session: the low-fidelity group used plastic models, and the high-fidelity group used human cadaver arms (brachial arteries) to practice graft-to-arterial anastomosis. One week later, all subjects participated in an animal laboratory in which they performed a single vascular anastomosis on a live, anesthetized pig (femoral artery). A blinded vascular surgeon scored candidate performance in the animal laboratory by using previously validated end points, including a checklist and final product analysis score. RESULTS: Acquisition of skill was significantly affected by model fidelity and level of training as measured by both the checklist (P = .03) and final product analysis (P = .01; Kruskal-Wallis). Specifically, junior residents practicing on high-fidelity models scored better on the checklist (P = .05) and final product analysis (P = .04). Senior residents practicing on high-fidelity models scored better on final product analysis (P < .05). CONCLUSIONS: Training in the laboratory does improve skill when assessed in a realistic setting. Both expertise groups showed better skill transfer from the bench model to live animals when practicing on high-fidelity models. For vascular anastomosis, it is important to provide appropriate model fidelity for trainees of different abilities to optimize the effectiveness of bench model training.     

The effect of bench model fidelity on endourological skills: a randomized controlled study

PURPOSE: Complex skills, such as ureteroscopy and stone extraction, are increasingly taught to novice urology trainees using bench models in surgical skills laboratories. We determined whether hands-on training improved the performance of novices more than those taught only by a didactic session and whether there was a difference in the performance of subjects taught on a low versus a high fidelity model. MATERIALS AND METHODS: We randomized 40 final year medical students to a didactic session or 1 of 2 hands-on training groups involving low or high fidelity bench model practice. Training sessions were supervised by experienced endourologists. Testing involved removal of a mid ureteral stone using a semirigid ureteroscope and a basket. Blinded examiners tested subjects before and after training. Performance was measured by a global rating scale, checklist, pass rating and time needed to complete the task. RESULTS: There was a significant effect of hands-on training on endourological performance (p <0.01). With respect to bench model fidelity the low fidelity group did significantly better than the didactic group (p <0.05). However, no significant difference was found between the high and low fidelity groups (p >0.05). The low fidelity model cost Canadian $20 to produce, while the high fidelity model cost Canadian $3,700 to purchase. CONCLUSIONS: Hands-on training using bench models can be successful for teaching novices complex endourological skills. A low fidelity bench model is a more cost-effective means of teaching ureteroscopic skills to novices than a high fidelity model.     

Teaching life saving procedures: The impact of model fidelity on acquisition and transfer of cricothyrotomy skills to cadavers

Canadian Journal of Anesthesia/Journal canadien d'anesthésie -     

Laboratory based training in urological microsurgery with bench model simulators: a randomized controlled trial evaluating the durability of technical skill

PURPOSE: We evaluated the durability of laboratory based technical skills training in urological microsurgery using bench model simulators. METHODS AND MATERIALS: A total of 50 junior surgery residents (post-graduate years 1 to 3) were recruited to participate in a focused training program in urological microsurgery. Prior to training subjects were randomized to receive hands-on training with bench model simulators (silicone tubing or live rat vas deferens, 40) or didactic training alone (10). Four months following the original training program the technical performance of 18 returning subjects (13 from the bench model and 5 from the didactic training group) was reevaluated using a high fidelity, live animal model (vasovasostomy and rat vas deferens). Outcome measures included blinded, expert assessment of videotaped performance using checklists and global rating scores, and evaluation of anastomotic patency. RESULTS: The retention test checklist (p <0.001), global rating scores (p <0.001) and anastomotic patency rates (p = 0.05) in the live animal model remained significantly higher for subjects who originally received hands-on bench model training compared with those who received didactic training alone. The number of interim practice opportunities with microsurgery correlated significantly with expert global ratings of surgical performance irrespective of the nature of training (r = 0.54, p = 0.02). CONCLUSIONS: Laboratory based technical skills training with bench models can lead to a significant retention of technical skill by novice surgeons. Measured performance improvements appear to be durable with time. However, the opportunity for repeat hands-on practice appears to maximize the retention of technical skill.     

The impact of external feedback on computer-assisted learning for surgical technical skill training

BACKGROUND: Computer-assisted learning (CAL) offers a number of potential advantages for surgical technical skills teaching. The purpose of this study was to evaluate the impact of individualized external feedback on surgical skill acquisition when a CAL package is used for instruction. METHODS: Freshman and sophomore students participated in a 1-hour CAL session designed to teach them how to tie a two-handed square knot. One group received individualized external feedback during the session and the other group did not. Subjects were videotaped performing the skill before and after the session. The tapes were independently analyzed, in blinded fashion, by three surgeons. Three measures were obtained: the total time for the task, whether or not the knot was square, and the general quality of the performance using a rating scale. RESULTS: Data from 105 subjects were available for final analysis. For both groups there were significant increases in the proportion of knots that were square when the posttest performance was compared with the pretest performance but there was no difference between groups on this measure. Comparison of the performance scores demonstrated that both groups had a significant improvement after the session but the performance scores were significantly better in the group that had received feedback. CONCLUSIONS: Novices in both groups using CAL showed improvement in two of the outcomes measured, suggesting that subjects in both groups attained some degree of competence with this skill. The higher posttest performance score for the group receiving feedback demonstrates that external feedback results in a higher level of mastery when CAL is used to teach surgical technical skills.     

Assessment of technical skills transfer from the bench training model to the human model

BACKGROUND: This study examines whether technical skills learned on a bench model are transferable to the human cadaver model. METHODS: Twenty-three first-year residents were randomly assigned to three groups receiving teaching on six procedures. For each procedure, one group received training on a cadaver model, one received training on a bench model, and one learned independently from a prepared text. Following training, all residents were assessed on their ability to perform the six procedures. RESULTS: Repeated measures analysis of variance revealed a significant effect of training modality for both checklist scores (F(2,44) = 3.49, P <0.05) and global scores (F(2,44) = 7.48, P <0.01). Post-hoc tests indicated that both bench and cadaver training were superior to text learning and that bench and cadaver training were equivalent. CONCLUSIONS: Training on a bench model transfers well to the human model, suggesting strong potential for transfer to the operating room.     

Effectiveness of repeated video feedback in the acquisition of a surgical technical skill.

BACKGROUND: Previously we evaluated the effectiveness of videotaped feedback as a teaching tool for surgical residents using 3 different core skills in the field of orthopedics. Our results revealed no significant differences in technical skill among surgical residents who were exposed to videotaped feedback and those who were not. Several limitations in the study were identified, including the presence of only a single exposure to videotaped feedback. In the present study we included repeated exposures to determine if skill acquisition was enhanced. METHODS: Thirty-three surgical residents were randomly assigned to receive either no videotaped feedback (control group) or repeated video feedback over 3 consecutive weekly practice sessions on a vascular anastomosis bench model. On the fourth week, vascular surgeons blinded to the 2 groups evaluated the residents on the same vascular anastomosis task using a global rating scale and technical checklist forms. RESULTS: Twenty-six (79%) of the residents participated. Independent t tests comparing the scores of each of the 2 different measures between the control group and repeated videotaped feedback group revealed no statistically significant differences. CONCLUSIONS: There was no significant difference in the performance of a vascular anastomosis in a bench-training model between residents who were exposed to video feedback over several practice sessions and those who received no video feedback.     

Burn injury and pulmonary sepsis: development of a clinically relevant model

BACKGROUND: Despite improvements in the early resuscitation of the critically injured, mortality from multiple organ failure has remained stable, with the lung often the first organ to fail. Early intubation and mechanical ventilation predispose patients to the development of pneumonia and respiratory failure. Our objective was to establish a murine model of combined injury, consisting of burn/trauma and pulmonary sepsis with reproducible end-organ responses and mortality. METHODS: Male B6D2F1 mice were divided into four groups: burn/infection (BI), burn (B), infection (I), and sham (S). Burned animals had a full-thickness 15% dorsal scald burn. BI and I groups were inoculated intratracheally with Pseudomonas aeruginosa (3-5 x 103 colony-forming units). S and B animals received saline intratracheally. All animals were resuscitated with 2 mL of intraperitoneal saline. Mortality was recorded at 24, 48, and 72 hours. Bacterial sepsis was confirmed by tissue Gram's stain of the lungs and positive organ and blood cultures for Pseudomonas aeruginosa. Femoral bone marrow cells were collected at 72 hours from surviving animals. Clonogenic potential was assessed by response to macrophage (M) colony-stimulating factor (CSF) and granulocyte-macrophage (GM) CSF in a soft agar assay and the data were represented as colonies per femur. Isolated alveolar macrophages and whole lung tissue were assayed for levels of the inflammatory cytokines tumor necrosis factor-alpha and interleukin-6. RESULTS: Mortality at 72 hours was 30% in BI, 12% in I, and <10% in B and S groups. Pneumonia was documented in all infected animals at 24 hours by Gram's stain and positive tissue cultures for Pseudomonas aeruginosa. Systemic sepsis as confirmed by blood, and remote organ cultures was seen in BI animals only. Significantly increased responsiveness to M-CSF stimulations was noted in all groups (BI, 8,291 +/- 1,402 colonies/femur; B, 6,357 +/- 806 colonies/femur; and I, 8,054 +/- 1,112 colonies/femur; p < 0.05) relative to sham (3,369 +/- 883 colonies/femur, p < 0.05). Maximal responsiveness to GM-CSF stimulation was noted in the BI group (11,932 +/- 982 colonies/femur, p < 0.05), and similar GM responsiveness was noted in all other groups (B, 7,135 +/- 548 colonies/femur; I, 7,023 +/- 810 colonies/femur; and S, 6,829 +/- 1,439 colonies/femur). Alveolar macrophage release of the proinflammatory cytokines tumor necrosis factor-alpha and interleukin-6 increased in all animals, but the magnitude of increase was not proportional to the strength of the inciting stimulus. CONCLUSION: Although minimal perturbations were seen after burn or pulmonary infection alone, the combined insult of burn and pulmonary sepsis resulted in statistically significant hematopoietic changes with increased monocytopoiesis. Only the combined injury resulted in systemic sepsis and significantly increased mortality. We have developed a clinically relevant model of trauma and pulmonary sepsis that will allow further clarification of the inflammatory response after injury and infection.     

The impact of donor cocaine use on the outcome of adult liver transplantation

BACKGROUNDS: To investigate the feasibility of adult liver transplantation from donors with cocaine use. METHODS: Of 807 adult liver transplantations performed between 1994 and 2000, 72 donors (8.9%) were current cocaine users. Donor characteristics and post-transplantation outcomes were retrospectively compared between the 72 cocaine and 126 control group selected from the remaining 735 donors, matched for age and having no history of drug use. RESULTS: Marijuana, opiates and amphetamines were drugs of abuse often present with cocaine. Except for a high incidence of acute alcohol use in the cocaine donors, donor characteristics were comparable. The cocaine group had a significantly higher graft loss within three months of transplant (18.1% vs. 7.9%, p < 0.05), and had a trend toward lower graft survival (76% vs. 86% at one yr). CONCLUSIONS: Potential adverse effect of cocaine and substances concurrently involved on donor liver was suggested. To clarify the distinct acceptance criteria of cocaine users for liver donation, prospective study is warranted.     

The effect of hemopure on coagulation in clinically relevant concentrations

Hemopure is a new colloidal blood substitute that may influence coagulation. We designed this study to examine the influence of this product on in vitro coagulation of whole blood by using the thrombelastograph (TEG). Blood samples from 20 volunteers were obtained. Hemopure was added to blood samples to obtain 0.5, 1, and 2 g/dL mixtures of Hemopure in blood. Control consisted of an undiluted sample and, for comparison, two samples diluted with volumes of lactated Ringer's solution (LR) equivalent to the two higher Hemopure dilutions. TEG with Hemopure at a concentration of 2 g/dL showed significantly shorter reaction and clot formation k times and an increased alpha angle compared with control. LR dilution with equivalent volume to 2 g/dL Hemopure solution also resulted in significantly shorter reaction and k times, as well as an increased alpha angle. Coagulation in samples with Hemopure at concentrations of 0.5 and 1 mg/dL did not vary significantly from control. Maximum amplitude did not vary significantly from control in any samples. The effect of Hemopure on TEG measures of coagulation is not significantly different from that of LR at clinically relevant concentrations.     

The impact of the AIS 2005 revision on injury severity scores and clinical outcome measures

Background

The abbreviated injury scale (AIS) was updated in 2005 from the AIS 1998 version. The purpose of this study is to describe the effects of this change on injury severity scoring and outcome measures.

Materials and methods

Analyses were performed on all trauma patients consecutively admitted over a 6-month period at two geographically separate Level I trauma centers. Injuries were manually double-coded according to the AIS 05 and the AIS 98. Changes in AIS, ISS, and new ISS (NISS) were analysed using paired t-tests. Apparent differences in outcome by ISS strata (<16, 16-24, >24) were compared for AIS 05 versus AIS 98 using the Wald-type statistic. Lastly, the percent of patients with a change in ISS strata are reported.

Results

There were 2250 patients included in the study. Nearly half (46.4%) of AIS codes changed, resulting in a different AIS score for 18.9% of all codes. The mean ISS was significantly lower using the AIS 05 (11.7) versus the AIS 98 (13.3, p < 0.001). Similarly, the mean NISS was significantly lower (16.3 versus 18.7, p < 0.001). In the ISS strata 16-24 an apparent increase in mortality, length of stay, and percent of patients not discharged home was observed for the AIS 05 versus AIS 98. Changes in outcome measures for this stratum were as follows (AIS 98 versus AIS 05): mortality, 4.3% versus 7.7% (p = 0.002); hospital length of stay, 5.2 days versus 7.3 days (p < 0.001); percent of patients not discharged home, 39.2% versus 49.3% (p < 0.001). Finally, there was a 20.5% reduction in patients with an ISS ≥ 16 and a 26.2% reduction in patients with an ISS ≥ 25 using the AIS 05.

Conclusions

The AIS revision had a significant impact on overall injury severity measures, clinical outcome measures, and percent of patients in each ISS strata. Therefore, the AIS revision affects the ability to directly compare data generated using AIS 05 and AIS 98 which has implications in trauma research, reimbursement and ACS accreditation.     

The use of shoulder scoring systems and outcome measures in the UK

IntroductionIn future, outcomes following shoulder surgery may be subject to public survey. Many outcome measures exist but we do not know whether there is a consensus between shoulder surgeons in the UK. The aim of this study was to survey the preferred outcome measures used by National Health Service (NHS) shoulder surgeons operating in the UK.MethodsA total of 350 shoulder surgeons working in NHS hospitals were asked to complete a short written questionnaire regarding their use of scoring systems and outcome measures. Questionnaires were sent and responses were received by post.ResultsOverall, 217 responses were received (62%). Of the respondents, 171 (79%) use an outcome measure in their shoulder practice while 46 (21%) do not. There were 118 surgeons (69%) who use more than one outcome measure. The Oxford shoulder score was most commonly used by 150 surgeons (69%), followed by the Constant score with 106 (49%), the Oxford shoulder instability score with 82 (38%), and the Disabilities of the Arm, Shoulder and Hand score with 54 (25%). The less commonly used outcome measures were the SF-36® and SF-12® health questionnaires with 19 (9%), the University of California at Los Angeles activity score with 8 (4%), the American Shoulder and Elbow Surgeons shoulder assessment form with 8 (4%) and the EQ-5D™ with 10 (3%).ConclusionsValidated outcome measures should be adopted by all practising surgeons in all specialties. This will allow better assessment of treatments in addition to assessment of surgical performance in a transparent way.     

The use of patient-reported outcome measures in the literature on traumatic foot fractures: A systematic review

IntroductionAdequate foot function is paramount in daily activities, yet the incidence of foot fractures shows a rising trend. Patient-reported outcome measures are increasingly used for research; however, the use of a wide variety of available instruments is undesirable. In the current study, an overview is provided of patient-reported outcome measures used in clinical research evaluating outcomes of foot fractures. Tools are provided to choose the most adequate instrument in future research.MethodsTo identify the instruments, a systematic review was performed using PubMed, Embase, and the Cochrane Library. Articles published since 2000, reporting on traumatic foot fractures and/or their posttraumatic sequelae, and using a minimum of one condition- or region-specific patient-reported outcome measure were included. Forty-nine instruments were identified, used 636 times collectively. These instruments were evaluated on frequency of use, bones or joints analyzed with the instruments, the type and amount of contained items, and existing literature on their psychometric properties.ResultsThe American Orthopaedic Foot and Ankle Society Ankle-Hindfoot Scale was used predominantly (AOFAS Ankle-Hindfoot Scale; n = 243, 38.2%), followed by the Maryland Foot Score (n = 90, 14.2%). Twenty-seven instruments were included for further analysis. The majority included questions on mobility (27/27) and pain (24/27). Tools to select an adequate instrument for new research are presented in the appendices.DiscussionControversy surrounds the AOFAS Ankle-Hindfoot Scale as other authors have found that its psychometric properties, indicating it measures what it is supposed to measure adequately, are flawed.ConclusionA multitude of specific patient-reported outcome measures concerning foot fractures exists. Furthermore, the predominantly used instrument is deemed insufficient regarding quality as found by other studies. A valid, reliable, and responsive patient-reported outcome measure for clinical research on foot fractures is necessary. The most adequate existing ones for future research on different topics can be found through the tools provided.     

Rat epigastric pedicle model: a clinically relevant evaluation of 1-mm PTFE grafts

Twenty-eight Sprague-Dawley rats had 1.0-mm polytetrafluoroethylene (PTFE) interposition grafts placed in their femoral artery that supplied a 3.0 X 3.0 cm epigastric pedicle flap. The model is the first to evaluate 1.0-mm PTFE under rigorous, clinically simulating conditions. Anastomoses employed a new, continuous telescoping suture technique. Grafts were selected for histological and electron microscopic evaluation, which confirmed the development of a cellular neointimal lining. Viability of the flap model had a 90% correlation with graft patency. Overall graft patency was 50%. Patency was documented in some specimens harvested at 200 days. The flap model is a good indicator of graft patency. PTFE grafts of 1.0-mm internal diameter are not yet equivalent to autologous veins. Future refinements, particularly aseptic technique, are expected to result in even higher patency rates.     

Ischemia/reperfusion: a clinically relevant model of intestinal injury yielding systemic inflammation

Background/Purpose

Multisystem organ failure (MSOF) is a major cause of morbidity and mortality in the critically ill patient. Animal models of endotoxin-induced sepsis were used to develop therapeutic regimens, which thus far have failed in clinical trials. Because multiple etiologies of MSOF affect the intestine, the authors hypothesized that during sepsis the gut may act as a possible trigger of the inflammatory cascade. As ischemia and reperfusion of the small intestine disrupts gut barrier function, thereby activating systemic inflammatory responses, the authors evaluated a murine model of ischemia/reperfusion to investigate these systemic responses to local mucosal and epithelial injury.

Methods

C57BL/10 and Balb/c mice underwent variable amounts of gut ischemia by superior mesenteric artery occlusion. Animals were evaluated for survival as well as gross and microscopic intestinal damage.

Results

Maximal ischemic damage occurred in the distal jejunum and proximal ileum. More severe epithelial damage and transmural inflammation were observed in C57BL/10 mice, which correlated with a higher mortality.

Conclusions

This model mimics what is observed clinically with intestinal injury resulting from a progressive ischemic insult with eventual systemic manifestations. This reproducible model of systemic inflammation elicits variable responses from genetically different animals, the results of which may lead to a better understanding of MSOF.     

The surgeon's technical skill in suturing: An analysis of the actual suture tracks

Ideal suturing was defined as advancing a needle along its curvature (needle circle) to minimize tissue trauma, while placing the suture with its intended span and tissue bite in the expected place. Actual suture tracks were analyzed to find the keys to produce such suturing. Correspondence of those tracks to the ideal track was then determined by the span, the initial needle angle (IA) into the tissue, and the center of the needle circle. Eight surgeons with 4–7 years of experience produced 22 ideal sutures in two types of tissue simulants: The entrance and exit points of the needle were level in flat suturing, while the entrance point was slanted 45 degrees for slant suturing. The correspondence was better with slant suturing than flat suturing (P<0.01). The IA in flat suturing was 49.0±2.0 (mean±SE) degrees versus 33.0 for ideal suturing (P<0.01), while that in slant suturing was 35.5±1.9 (P: ns). In conclusion, the IA was the key to good results, and was optimized in slant suturing, which was instinctively utilized in practice by using forceps. The forceps avoided a derangement of suturing stemming from the configuration of the needle employed and from the range of motion of the surgeon's arm (human engineering), while satisfying the surgeons inclination to take a large IA.This study was presented, in part, at the 34th World Congress of Surgery of the International Society of Surgery, Stockholm, Sweden, August 25–31, 1991This study was supported, in part, by Grants (Research C Nos. 02807128, 1990 and 03670657, 1991) from the Ministry of Education, Science and Culture, Japan