PubMed Health⌕ Search

Biomedical subjects

Adam Dubrowski

Publications and source records attributed to Adam Dubrowski.

At least 19 recordsLinked to original sources
PubMed2007

Verbal feedback from an expert is more effective than self-accessed feedback about motion efficiency in learning new surgical skills.

BACKGROUND: Teaching of technical surgical skills to undergraduate medical students in a laboratory setting away from the patient is not common practice. Because of the large volume of students and shortage of available teaching faculty new methods of teaching must be developed for this group of trainees. In this study we examined the effectiveness of computer-based video training, different types of computer-based motion efficiency feedback (with and without expert criteria), and expert feedback on learning of a basic technical skill in medical students. METHODS: Forty-five junior medical students were randomized into 3 groups and learned suturing and knot-tying skills. Group A received computer-generated feedback about the economy of their movements. Group B received the same motion economy feedback, as well as expert reference values. Group C received verbal feedback from an expert. All groups were pre-tested, allowed 18 practice trials, and post-tested, and their skill retention was retested after 1 month. Performance was assessed by expert analysis using an objective structured analysis of technical skill and by computer analysis (Imperial College Surgical Assessment Device [ICSAD]). RESULTS: All groups showed improvement from pre-test to post-test. However, only group C showed retention of skill on delayed performance testing. CONCLUSIONS: Verbal feedback from an expert instructor led to lasting improvements in technical skills performance. Providing information about motion efficiency did not lead to similar improvements.

Biofeedback, Psychology↗
PubMed2007

Using a virtual reality temporal bone simulator to assess otolaryngology trainees.

OBJECTIVE: The objective of this study is to determine the feasibility of computerized evaluation of resident performance using hand motion analysis on a virtual reality temporal bone (VR TB) simulator. We hypothesized that both computerized analysis and expert ratings would discriminate the performance of novices from experienced trainees. We also hypothesized that performance on the virtual reality temporal bone simulator (VR TB) would differentiate based on previous drilling experience. STUDY DESIGN: The authors conducted a randomized, blind assessment study. METHODS: Nineteen volunteers from the Otolaryngology-Head and Neck Surgery training program at the University of Toronto drilled both a cadaveric TB and a simulated VR TB. Expert reviewers were asked to assess operative readiness of the trainee based on a blind video review of their performance. Computerized hand motion analysis of each participant's performance was conducted. RESULTS: Expert raters were able to discriminate novices from experienced trainees (P < .05) on cadaveric temporal bones, and there was a trend toward discrimination on VR TB performance. Hand motion analysis showed that experienced trainees had better movement economy than novices (P < .05) on the VR TB. CONCLUSION: Performance, as measured by hand motion analysis on the VR TB simulator, reflects trainees' previous drilling experience. This study suggests that otolaryngology trainees could accomplish initial temporal bone training on a VR TB simulator, which can provide feedback to the trainee, and may reduce the need for constant faculty supervision and evaluation.

Cadaver↗
PubMed2006

Tensiometry as a measure of improvement in knot quality in undergraduate medical students.

INTRODUCTION: This study examined the validity of tensiometry as an objective method of assessing the improvements in the quality of knots and technical performance due to practice on suturing and knot-tying skills. METHODS: We evaluated the quality of 1,830 knots produced by undergraduate medical students before training (pre-test), after (post-test), and after a week retention (retention-test) using tensiometry. These results were compared to expert-based assessments of products and performance. RESULTS: Tensiometry, as well as expert-based assessments can detect changes in the quality of knots and technical performance from pre to post and retention-test ( p<0.05). However, these three methods may assess different dimensions of the same products and actions. CONCLUSIONS: The development of trainee evaluation criteria for the acquisition of surgical skills is a crucial element in surgical education. Based on our patterns of results it is hypothesized that tensiometry can serve as an economic first approximation of the quality of knots and suturing performance.

Analysis of Variance↗
PubMed2006

Control of laparoscopic instrument motion in an inanimate bench model: implications for the training and the evaluation of technical skills.

Computer-assisted analysis of wrist movement has recently emerged as an objective laparoscopic performance evaluation method. The first purpose of this study was to assess the differences in motion characteristics between the tip of the instrument and the wrist. The second purpose was to describe the control strategies used to move laparoscopic instruments. During a bead transfer task, motions of a laparoscopic needle driver's tip, heel, and the participants' wrist were monitored. Results showed that large amplitude movements were best described by movements of the wrist, and small amplitude movements were evidenced by motions of the instrument tip. Thus, for describing expertise, and for evaluation and feedback, motion of the tip of the laparoscopic instrument should be quantified, in addition to motion of the wrist. The motions of the instrument were controlled by utilizing the flexibility of the skin of the laparoscopic trainer in addition to using the fulcrum, and sliding through the trocar. In order to increase fidelity, virtual reality trainers should simulate the flexibility of the real structures around the insertion of the instrument.

Adult↗
PubMed2006

Computer-assisted assessment of one-handed knot tying skills performed within various contexts: a construct validity study.

BACKGROUND: The widespread use of computer-assisted assessment of technical proficiency in surgical residents shows the need for further investigations of the construct validity of these devices (eg, hand motion analysis) before implementation into competency testing. METHODS: Thirty general surgery residents performed 1-handed knot tying in 2 contexts: superficial and deep. The Imperial College Surgical Assessment Device (ICSAD) was used to evaluate performance. It was hypothesized that senior residents (postgraduate year [PGY] 4-5) would perform better then junior residents (PGY 1-3) and that the superficial version of the skill would be easier than the deep. RESULTS: Technical efficiency scores were better for seniors than for juniors (P < .001) and on the superficial versus the deep model (P < .001). Both groups were equally affected by the contextual changes to the skill, suggesting a consistent impact on the skill-specific movement patterns. CONCLUSIONS: Additional evidence for the validity of ICSAD as a competency assessment tool has been shown. First, it distinguished senior and junior residents. Second, it discerned differences on the same skill performed in 2 different contexts.

Clinical Competence↗
PubMed2006

Teaching technical skills to surgical residents: a survey of empirical research.

We review a series of empirical studies on the use of simulators and bench models in training technical skills and subsequent retention of those skills. We discuss recent research on the transfer of training from bench models and simulators to the clinical setting and provide a theoretical structure to organize the findings. The transfer of training from inanimate bench models and simulators to live patients has recently been demonstrated in a number of areas. The effectiveness of this training is enhanced if focus is placed on the operative, or process-oriented, aspects of the procedure, with suspension of disbelief regarding the physical structure of the training platform. The retention of trained skills is an area of research only beginning to evolve, with recent results suggesting that effective retention can be demonstrated if training is tightly focused and involves an entire procedure. An emerging area of research involves the use of simulators as assessment instruments for high-stakes testing, and recent results involving simulated trauma management support this novel application. Based on these findings, we encourage the use of a wide variety of high- and low-fidelity platforms, with emphasis on training procedural knowledge involving an entire procedure.

Clinical Competence↗
PubMed2006

Teaching surgical skills: what kind of practice makes perfect?: a randomized, controlled trial.

OBJECTIVE: Surgical skills laboratories have become an important venue for early skill acquisition. The principles that govern training in this novel educational environment remain largely unknown; the commonest method of training, especially for continuing medical education (CME), is a single multihour event. This study addresses the impact of an alternative method, where learning is distributed over a number of training sessions. The acquisition and transfer of a new skill to a life-like model is assessed. METHODS: Thirty-eight junior surgical residents, randomly assigned to either massed (1 day) or distributed (weekly) practice regimens, were taught a new skill (microvascular anastomosis). Each group spent the same amount of time in practice. Performance was assessed pretraining, immediately post-training, and 1 month post-training. The ultimate test of anastomotic skill was assessed with a transfer test to a live, anesthetized rat. Previously validated computer-based and expert-based outcome measures were used. In addition, clinically relevant outcomes were assessed. RESULTS: Both groups showed immediate improvement in performance, but the distributed group performed significantly better on the retention test in most outcome measures (time, number of hand movements, and expert global ratings; all P values <0.05). The distributed group also outperformed the massed group on the live rat anastomosis in all expert-based measures (global ratings, checklist score, final product analysis, competency for OR; all P values <0.05). CONCLUSIONS: Our current model of training surgical skills using short courses (for both CME and structured residency curricula) may be suboptimal. Residents retain and transfer skills better if taught in a distributed manner. Despite the greater logistical challenge, we need to restructure training schedules to allow for distributed practice.

Animals↗
PubMed2006

Randomised, controlled study investigating the optimal instructor: student ratios for teaching suturing skills.

INTRODUCTION: Recently, there has been a shift away from practising procedures on patients for the first time and towards bench model teaching of clinical skills to undergraduate medical students. However, guidelines for the most effective instructor : student ratio for technical skills training are unclear. This has important implications for staffing laboratory based teaching sessions. The purpose of this study was to assess the optimal ratio of teachers to learners during the teaching of a simulated wound closure. METHODS: A total of 108 undergraduate medical students participated in a 1-hour course on wound closure. They were randomised to 3 groups, each with a different instructor:student ratio (Group A: 6-12; Group B: 3-12; Group C: 1-12). Students were evaluated on a pre-test, an immediate post-test and a delayed retention test using an objective, computer-based technical skills assessment method. Collectively termed the "economy of movements", the total time taken to complete the task and the number of movements executed were the primary outcome measures. RESULTS: Improvements in the economy of movements were the same for Groups A and B and were better than in Group C (P < 0.005). DISCUSSION: The optimal instructor:student ratio was 1 instructor for 4 students. Higher ratios of instructors to students resulted in no improvements in learning, and lower ratios of instructors to students resulted in significantly less learning. These findings are in keeping with current motor learning theories.

Analysis of Variance↗
PubMed2005

The influence of practice schedules in the learning of a complex bone-plating surgical task.

BACKGROUND: Practicing surgical tasks on bench models can be arranged in 3 ways: as the entire task, or as individual skills practiced separately in blocked or random order. The issue of the optimal practice schedule for the acquisition of surgical tasks is critical for enhancing training programs. METHOD: An orthopedic bone-plating task was practiced as a whole, or in parts in either a random or a blocked order. Learning was assessed on global ratings, checklists, and final product analysis before, immediately after, and an hour after practice. RESULTS: Checklists, and final product analysis, but not the global ratings showed that practicing the entire task resulted in the most learning, followed by the random practice. Practice of the skills in a blocked order yielded the least amount of learning. CONCLUSIONS: It is recommended that surgical tasks composed of several discrete skills should be practiced as a whole. However, if part practice is necessary, these skills should be arranged in random order to optimize learning.

Analysis of Variance↗
PubMed2005

Quantification of motion characteristics and forces applied to tissues during suturing.

BACKGROUND: The quantification of movement processes describes how a movement is generated. These process measures have been shown to be effective sources of feedback to facilitate motor learning and can thus be applied to teach fundamental technical skills in surgery. The aim of this study was to determine, through detailed analyses, whether specific process measures of hand motions and forces imposed on tissues during suturing were sensitive to (1) practice and (2) levels of surgical expertise. METHODS: Six junior surgical residents (PGY-1) and 7 faculty surgeons were required to perform 20 simulated sutures on an artificial artery model, during which time the performers' hand movements were tracked by electromagnetic markers and the quantity of force they applied was measured by a force platform holding the arterial suturing models. The amount of wrist rotation and peak hand velocity produced during the suturing movement, peak and average forces applied to the tissue, the temporal difference between force and wrist rotation onsets, and the total suturing time were evaluated. RESULTS: Surgeons showed greater wrist rotation, higher average forces, shorter force-rotation initiation times, and shorter suturing times than did junior residents. Only the amount of wrist rotation and the time elapsed between force and wrist rotation onsets improved with practice for the junior group. CONCLUSIONS: Although all 4 variables measured can be used to distinguish between expert and novice performances, only the process measures (wrist rotation and force-rotation initiation time) changed as a result of practice for the junior residents. Thus, these measures can be used to facilitate skills learning by serving as a source of detailed structured feedback to trainees.

Clinical Competence↗
PubMed2005

Unilateral basal ganglia damage causes contralesional force control deficits: a case study.

When grasping to lift an object, the grip force is usually scaled to the mass of the object. However, it has been shown that lifting objects of different sizes but equal masses results in the generation of higher forces for larger compared to smaller objects. The objective of this study was to investigate whether a similar effect is present in an individual (RI) with a unilateral lesion to the basal ganglia (BG). It was hypothesized that if the BG have an influence on the use of visual information in updating of the internal model used to anticipate the forces required for grasping, damage to these structures should result in the inability of RI's contralesional hand to anticipate object mass based on size cues. To test this hypothesis three objects of equal mass but different sizes were grasped and lifted by RI and six control individuals. The forces that were generated during these lifts were quantified. The controls showed the expected increases in peak grip force as object size increased. RI showed no effect of object size for his contralesional hand, but did show force scaling with his ipsilesional hand. In conclusion, RI's BG damage affected the on-line control of grip forces and the inability to integrate visual and tactile information in the programming of finger forces.

Adult↗
PubMed2005

Computer-based video instructions for acquisition of technical skills.

This study aimed to assess which type of information presented in an interactive computer-based video instruction was most frequently used by novice medical students during a 1-hour training session in instrument suturing and knot-tying skills. Custom-designed instructional software enabled tracking when a given segment of the video was accessed. The results suggest that, in the early stages of learning, trainees require guidance in proper looping techniques and placement of the knots. In accordance with motor learning theory, when setting up CD-ROM or Web-based curricula, instructors should, therefore, emphasize these steps during early stages of learning.

CD-ROM↗
PubMed2005

Effective training and assessment of surgical skills, and the correlates of performance.

This report briefly describes the University of Toronto Surgical Skills Centre and summarizes research in technical skills conducted at that site. This includes work on curriculum evaluation, the development and validation of assessment instruments, the retention of technical skills after training, and the prediction of success in surgery. These studies benefited from the large number of participants made available by the Surgical Skills Centre, allowing for randomized controlled studies or correlation studies where larger numbers are necessary for adequate statistical power. Recent emphasis has been on the further development of objective means of assessment and the exploration of correlates of surgical performance. Ongoing research is also aimed at simulator validation.

Clinical Competence↗
PubMed2005

Control of laparoscopic instrument motion in an inanimate bench model: implications for the training and evaluation of technical skills.

Laparoscopic surgery requires new methods of technical competency evaluation, as well as training. The first purpose was to assess the differences in motion characteristics between the tip of the instrument and the wrist. The second purpose was to determine whether similar control strategies are used to move instruments in virtual reality and bench model environments. Surgically naive participants were required to tap a laparoscopic instrument between two targets that differed in size and separation distance. Large amplitude movements were controlled with the movements of the wrist and small amplitude with the wrist and the fingers (p<.001). Participants utilized the flexibility of the skin of the laparoscopic trainer to facilitate their movements. These results suggest that monitoring the motions of the instrument tip is a more precise indication of its motions than are motions of the wrist when movements of small amplitudes are produced. Moreover, in order to increase fidelity, VR trainers should simulate the flexibility of the real structures around the insertion of the instrument.

Canada↗
PubMed2005

Structural flexibility of laparoscopic instruments: implication for the design of virtual reality simulators.

In accordance with the Practice Specificity Theory, training on models that closely resemble real life scenarios is most beneficial to learning. Research in the virtual reality (VR) simulation, as a potential teaching and evaluation tool, concentrated on the design of trainers to resemble operating room (OR) conditions. The purpose of the present investigation was to determine the structural flexibility of laparoscopic instruments of different materials and diameters under a wide range of stresses. Incorporating the mechanical properties of these instruments into the algorithms can prove to further increase the fidelity of VR simulators. The amount of deviation from pre-stress position in the instruments' shaft was measured with infrared markers and used as the index of structural flexibility. All instruments deviated considerably with the largest deviations observed for the small disposable, and lowest for the large reusable instruments. There was a linear relation between the stress and deviation for all instruments, which varied as a function of diameter. Similar instrument deviations were observed during cholecystectomy performed on porcine liver. Our findings show that laparoscopic instruments are not rigid bodies and are prone to significant deviations during standard laparoscopic procedures. This suggests that the structural flexibility of laparoscopic instruments should be modeled in the design of VR simulators.

Canada↗
PubMed2004

Practice effects on the use of visual and haptic cues during grasping.

Mapping of arbitrary color cues onto object properties such as mass can influence the control of fingertip forces. One can view the development of that mapping as a motor learning issue, and its development should therefore be influenced by practice schedule. During an acquisition phase, 24 participants lifted color-cued objects that differed in mass. The masses were presented in either blocked or random orders. A test phase consisted of lifts of a midmass object; on some lifts, the object's mass was unexpectedly changed. The change was either accurately color cued or miscued. Only blocked practice led to visually mediated scaling of fingertip forces to object mass. During the test phase, previous blocked practice resulted in reliance on visual cues, and random practice led to a reliance on haptics (sense of touch). Those findings suggest that the integration of arbitrary color cues and haptic information is dependent on practice conditions.

Adult↗
PubMed2002

Action-perception dissociation in response to target acceleration.

The purpose of this study was to investigate whether information about the acceleration characteristics of a moving target can be used for both action and perception. Also of interest was whether prior movement experience altered perceptual judgements. Participants manually intercepted targets moving with various acceleration, velocity and movement time characteristics. They also made perceptual judgements about the acceleration characteristics of these targets either with or without prior manual interception experience. Results showed that while aiming kinematics were sensitive to the acceleration characteristics of the target, participants were only able to perceptually discriminate the velocity characteristics of target motion, even after performing interceptive actions to the same targets. These results are discussed in terms of a two channel (action-perception) model of visuomotor control.

Acceleration↗