Quantifying technical skills during open operations using video-based motion analysis

Characterization of Surgical Movements As a Training Tool for Improving Efficiency

INTRODUCTION

Surgical experience is often reflected by efficient, fluid, and well-calculated movements. For a new trainee, learning these characteristics is possible only by observation as there is no quantification system to define these factors. We analyzed surgeons' hand movements with different experience levels to characterize their movements according to experience.

METHODS

Hand motions were recorded by an inertial measurement unit (IMU) mounted on the hands of the surgeons during a simulated surgical procedure. IMU data provided acceleration and Eulerian angles: yaw, roll, and pitch corresponding to hand motions as radial/ulnar deviation, pronation/supination, and extension/flexion, respectively. These variables were graphically depicted and compared between three surgeons.

RESULTS

Participants were assigned to three groups based on years of surgical experience: group 1: >15 y; group 2: 3-10 y; and group 3: 0-1 y. Visualization of the roll motion, being the main motion during suturing, showed the clear difference in fluidity and regularity of the movements between the groups, showing minimal wasted movements for group 1. The angle of the roll motion, measured at the minimum, midpoint, and maximum points was significantly different between the groups. As expected, the experienced group completed the procedure first; however, the acceleration was not different between the groups.

CONCLUSIONS

Surgeons' hand movements can be easily characterized and quantified by an IMU device for automatic assessment of surgical skills. These characteristics graphically visualize a surgeon's regularity, fluidity, economy, and efficiency. The characteristics of an experienced surgeon can serve as a training model and as a reference tool for trainees.

Enhancing surgical performance in cardiothoracic surgery with innovations from computer vision and artificial intelligence: a narrative review

When technical requirements are high, and patient outcomes are critical, opportunities for monitoring and improving surgical skills via objective motion analysis feedback may be particularly beneficial. This narrative review synthesises work on technical and non-technical surgical skills, collaborative task performance, and pose estimation to illustrate new opportunities to advance cardiothoracic surgical performance with innovations from computer vision and artificial intelligence. These technological innovations are critically evaluated in terms of the benefits they could offer the cardiothoracic surgical community, and any barriers to the uptake of the technology are elaborated upon. Like some other specialities, cardiothoracic surgery has relatively few opportunities to benefit from tools with data capture technology embedded within them (as is possible with robotic-assisted laparoscopic surgery, for example). In such cases, pose estimation techniques that allow for movement tracking across a conventional operating field without using specialist equipment or markers offer considerable potential. With video data from either simulated or real surgical procedures, these tools can (1) provide insight into the development of expertise and surgical performance over a surgeon's career, (2) provide feedback to trainee surgeons regarding areas for improvement, (3) provide the opportunity to investigate what aspects of skill may be linked to patient outcomes which can (4) inform the aspects of surgical skill which should be focused on within training or mentoring programmes. Classifier or assessment algorithms that use artificial intelligence to 'learn' what expertise is from expert surgical evaluators could further assist educators in determining if trainees meet competency thresholds. With collaborative efforts between surgical teams, medical institutions, computer scientists and researchers to ensure this technology is developed with usability and ethics in mind, the developed feedback tools could improve cardiothoracic surgical practice in a data-driven way.

Video-Based Coaching: Current Status and Role in Surgical Practice (Part 1) From the Society for Surgery of the Alimentary Tract, Health Care Quality and Outcomes Committee

Patient safety and outcomes are directly related to surgical performance. Surgical training emphasizes the importance of the surgeon in determining these outcomes. After training is complete, there is a lack of structured programs for surgeons to audit their skills and continue their individual development. There is a significant linear relationship between surgeon technical skill and surgical outcomes; however, measuring technical performance is difficult. Video-based coaching matches an individual surgeon in practice with a surgical colleague who has been trained in the core principles of coaching for individualizing instruction. It can provide objective assessment for teaching higher-level concepts, such as technical skills, cognitive skills, and decision-making. There are many benefits to video-based coaching. While the concept is gaining acceptance as a method of surgical education, it is still novel in clinical practice. As more surgeons look towards video-based coaching for quality improvement, a consistent definition of the program, goals, and metrics for assessment will be critical. This paper is a review on the status of the video-based coaching as it applies to practicing surgeons.

Evaluating the differences in the early laparoscopic donor nephrectomy learning curves of a Swiss high volume transplant program and a South African low volume transplant program after knowledge transfer

Background

To describe the retroperitoneoscopic donor nephrectomy learning curve differences between a high volume (training) hospital in Basel, Switzerland, and a low volume (trainee) hospital in Cape Town, South Africa, after knowledge transfer. The South African hospital is resource constraint in hospital and training equipment. Techniques for performing the surgery were near identical.

Methods

Both units maintained prospective databases. Comparisons were made of the first 74 cases in each database: Basel’s series were from 19 January 2001 until 28 June 2004, while the Cape Town Hospital were from 8 April 2008 until 15 July 2008. Four surgeons operated in the Basel group, while only one surgeon operated in the Cape Town group. Variables compared include operating time (first skin incision until kidney was extracted), warm ischaemic time (renal arterial occlusion until cold bench reperfusion), blood loss, graft function, and hospital stay. We also analysed the first and last 25 cases of each series. Subgroup analysis of a single Basel surgeon was conducted.

Results

Donor age (means: Basel vs. Cape Town 54 vs. 33 p < 0.0001) and gender (males vs. females Cape Town 57% male and Basel 31% male) differed widely. The Basel group did more left-sided operations (72% vs. 58%). Operative times, blood loss and donor creatinine did not differ. Warm ischaemic time was significantly shorter in the Basel group (Cape Town mean 204 s Basel mean 130 s P = 0.0023). There was double the number of early graft failures in the South African group (six vs. three)—not related to donor surgery. Both groups showed a decline in operating times, plateauing at 30–34 cases.

Conclusions

There are statistically significant differences in some aspects of the learning curves of the Swiss (training) and South African (trainee) hospitals. These differences are clinically not pronounced, and the knowledge transfer was worth the effort.

Toward Competency-Based Training: To What Extent Are We Competency-Based?

BACKGROUND

Time-based training models in plastic surgery vary in exposure, resulting in low confidence levels among graduates. The evolution of postgraduate medical education into a competency-based model to address these issues requires an understanding of interventions described in the plastic surgery literature to identify gaps and guide creation of assessments to demonstrate competence.

METHODS

A systematic search of the MEDLINE, Embase, Cumulative Index to Nursing and Allied Health Literature, PubMed, and Cochrane databases from inception until December of 2017 was conducted using search terms and synonyms of educational interventions reported in plastic surgery. Full texts were retrieved following filtering and data extracted were related to intervention design and execution, involvement of competency assessment, and educational objectives and alignment to Accreditation Council for Graduate Medical Education competencies and Royal College of Physicians and Surgeons of Canada Canadian Medical Education Directives for Specialists roles. Study quality was assessed using Kirkpatrick's levels of learning evaluation, validity evidence, and the Medical Education Research Study Quality Instrument score.

RESULTS

Of the initial 4307 results, only 36 interventions met the inclusion criteria. Almost all interventions aligned to medical knowledge and patient care Accreditation Council for Graduate Medical Education competencies. One-fifth of the interventions involved no assessment of competency, whereas most displayed assessment at the level of design as opposed to outcomes. Quality assessment revealed low levels of learning evaluation and evidence of validity; the average Medical Education Research Study Quality Instrument score was 10.9 of 18.

CONCLUSION

A systematic review of educational literature in plastic surgery was conducted to assess the quality of reported educational interventions, and to help guide creating tools that ensure competency acquirement among trainees.

Quantifying surgeon maneuevers across experience levels through marker-less hand motion kinematics of simulated surgical tasks

This paper compares clinician hand motion for common suturing tasks across a range of experience levels and tissue types. Medical students (32), residents (41), attending surgeons (10), and retirees (2) were recorded on digital video while suturing on one of: foam, pig feet, or porcine bowel. Depending on time in position, each medical student, resident, and attending participant was classified as junior or senior, yielding six experience categories. This work focuses on trends associated with increasing tenure observed from those medical students (10), residents (15), and attendings (10) who sutured on foam, and draws comparison across tissue types where pertinent. Utilizing custom software, the two-dimensional location of each of the participant's hands were automatically recorded in every video frame, producing a rich spatiotemporal feature set. While suturing on foam, increasing clinician experience was associated with conserved path length per cycle of the non-dominant hand, significantly reducing from junior medical students (mean = 73.63 cm, sd = 33.21 cm) to senior residents (mean = 46.16 cm, sd = 14.03 cm, p = 0.015), and again between senior residents and senior attendings (mean = 30.84 cm, sd = 14.51 cm, p = 0.045). Despite similar maneuver rates, attendings also accelerated less with their non-dominant hand (mean = 16.27 cm/s², sd = 81.12 cm/s², p = 0.002) than senior residents (mean = 24.84 cm/s², sd = 68.29 cm/s², p = 0.002). While tying, medical students moved their dominant hands slower (mean = 4.39 cm/s, sd = 1.73 cm/s, p = 0.033) than senior residents (mean = 6.53 cm/s, sd = 2.52 cm/s). These results suggest that increased psychomotor performance during early training manifest through faster dominant hand function, while later increases are characterized by conserving energy and efficiently distributing work between hands. Incorporating this scalable video-based motion analysis into regular formative assessment routines may enable greater quality and consistency of feedback throughout a surgical career.

Evaluation of Intraoperative Hand-Off Frequency, Duration, and Context: A Mixed Methods Analysis

BACKGROUND

Hand-offs in the operating room contribute to poor communication, reduced team function, and may be poorly coordinated with other activities. Conversely, they may represent a missed opportunity for improved communication. We sought to better understand the coordination and impact of intraoperative hand-offs.

METHODS

We prospectively audio-video (AV) recorded 10 operations and evaluated intraoperative hand-offs. Data collected included percentage of time team members were absent due to breaks, relationships between hand-offs and intraoperative events (incision, surgical counts), and occurrences of simultaneous hand-offs. We also identified announcement that a hand-off had occurred and anchoring, in which team members not involved in the hand-off participated and provided information.

RESULTS

Spanning 2919 min of audio-video data, there were 74 hand-offs (range, 4-14 per case) totaling 225.2 min, representing 7.7% of time recorded. Thirty-two (45.1%) hand-offs were interrupted or delayed because of competing activities; eight hand-offs occurred during an instrument or laparotomy pad count. Six cases had simultaneous hand-offs; two cases had two episodes of simultaneous hand-offs. Eight hand-offs included an announcement. Seven included anchoring. Evaluating both temporary and permanent hand-offs, one or more original team members was absent for 40.7% of time recorded and >one team member was absent for 20.5% of time recorded.

CONCLUSIONS

Intraoperative hand-offs are frequent and not well coordinated with intraoperative events including counts and other hand-offs. Anchoring and announced hand-offs occurred in a small proportion of cases. Future work must focus on optimizing timing, content, and participation in intraoperative hand-offs.

Video review for measuring and improving skill in urological surgery

Interest is growing within the urological surgery community for objective assessments of technical skill. Surgical video review relies on the use of objective assessment tools to evaluate both global and procedure-specific skill. These evaluations provide structured feedback to surgeons with the aim of improving technique, which has been associated with patient outcomes. Currently, skill assessments can be performed by using expert peer-review, crowdsourcing or computer-based methods. Given the relationship between skill and patient outcomes, surgeons might be required in the future to provide empirical evidence of their technical skill for certification, employment, credentialing and quality improvement. Interventions such as coaching and skills workshops incorporating video review might help surgeons improve their skill, with the ultimate goal of improving patient outcomes.

Using Surgeon Hand Motions to Predict Surgical Maneuvers

OBJECTIVE

This study explores how common machine learning techniques can predict surgical maneuvers from a continuous video record of surgical benchtop simulations.

BACKGROUND

Automatic computer vision recognition of surgical maneuvers (suturing, tying, and transition) could expedite video review and objective assessment of surgeries.

METHOD

We recorded hand movements of 37 clinicians performing simple and running subcuticular suturing benchtop simulations, and applied three machine learning techniques (decision trees, random forests, and hidden Markov models) to classify surgical maneuvers every 2 s (60 frames) of video.

RESULTS

Random forest predictions of surgical video correctly classified 74% of all video segments into suturing, tying, and transition states for a randomly selected test set. Hidden Markov model adjustments improved the random forest predictions to 79% for simple interrupted suturing on a subset of randomly selected participants.

CONCLUSION

Random forest predictions aided by hidden Markov modeling provided the best prediction of surgical maneuvers. Training of models across all users improved prediction accuracy by 10% compared with a random selection of participants.

APPLICATION

Marker-less video hand tracking can predict surgical maneuvers from a continuous video record with similar accuracy as robot-assisted surgical platforms, and may enable more efficient video review of surgical procedures for training and coaching.

Video Technologies for Recording Open Surgery: A Systematic Review

Video recording of surgical procedures is an important tool for surgical education, performance enhancement, and error analysis. Technology for video recording open surgery, however, is limited. The objective of this article is to provide an overview of the available literature regarding the various technologies used for intraoperative video recording of open surgery. A systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines using the MEDLINE, Cochrane Central, and EMBASE databases. Two authors independently screened the titles and abstracts of the retrieved articles, and those that satisfied the defined inclusion criteria were selected for a full-text review. A total of 2275 publications were initially identified, and 110 were included in the final review. The included articles were categorized based on type of article, surgical subspecialty, type and positioning of camera, and limitations identified with their use. The most common article type was primary-technical (29%), and the dominant specialties were general surgery (22%) and plastic surgery (18%). The most commonly cited camera used was the GoPro (30%) positioned in a head-mount configuration (60%). Commonly cited limitations included poor video quality, inadequate battery life, light overexposure, obstruction by surgical team members, and excessive motion. Open surgery remains the mainstay of many surgical specialties today, and technological innovation is absolutely critical to fulfill the unmet need for better video capture of open surgery. The findings of this article will be valuable for guiding future development of novel technology for this purpose.

Modeling Surgical Technical Skill Using Expert Assessment for Automated Computer Rating

OBJECTIVE

Computer vision was used to predict expert performance ratings from surgeon hand motions for tying and suturing tasks.

SUMMARY BACKGROUND DATA

Existing methods, including the objective structured assessment of technical skills (OSATS), have proven reliable, but do not readily discriminate at the task level. Computer vision may be used for evaluating distinct task performance throughout an operation.

METHODS

Open surgeries was videoed and surgeon hands were tracked without using sensors or markers. An expert panel of 3 attending surgeons rated tying and suturing video clips on continuous scales from 0 to 10 along 3 task measures adapted from the broader OSATS: motion economy, fluidity of motion, and tissue handling. Empirical models were developed to predict the expert consensus ratings based on the hand kinematic data records.

RESULTS

The predicted versus panel ratings for suturing had slopes from 0.73 to 1, and intercepts from 0.36 to 1.54 (Average R2 = 0.81). Predicted versus panel ratings for tying had slopes from 0.39 to 0.88, and intercepts from 0.79 to 4.36 (Average R2 = 0.57). The mean square error among predicted and expert ratings was consistently less than the mean squared difference among individual expert ratings and the eventual consensus ratings.

CONCLUSIONS

The computer algorithm consistently predicted the panel ratings of individual tasks, and were more objective and reliable than individual assessment by surgical experts.

Lack of online video educational resources for open colorectal surgery training

BACKGROUND

Video recordings of open surgical procedures could provide a method for enhancing surgical education, analysing operative performance and presenting cases to a wider audience of surgeons. The aim of this pilot study was to systematically search the World Wide Web to determine the availability of open surgery videos and to evaluate their potential training value in terms of the educational content presented.

METHODS

A broad search for open right hemicolectomy videos was performed on the three most used English language internet search engines (Google.com, Bing.com and Yahoo.com). All videos of open right hemicolectomy with an English language title were included. Laparoscopic surgery, single-incision laparoscopic surgery and robotic- and hand-assisted surgery videos were excluded, as were videos from fee charging websites.

RESULTS

A total of 31 relevant websites were identified and 21 open surgery videos were finally included. The characteristics of the patients were presented only in four (19%) videos. A video commentary was present in 12 cases (57.1%) and this was in English language in 11. The median number of views per month was 84.1.

CONCLUSIONS

Open surgery videos have a significantly higher number of views per month compared to laparoscopic surgery videos, but current methodologies used to record and render the surgeon's point of view in open operative surgery remain limited.

Familiarity and Communication in the Operating Room

BACKGROUND

Poor communication is implicated in many adverse events in the operating room (OR); however, many hospitals' scheduling practices permit unfamiliar operative teams. The relationship between unfamiliarity, team communication and effectiveness of communication is poorly understood. We sought to evaluate the relationship between familiarity, communication rates, and communication ineffectiveness of health care providers in the OR.

MATERIALS AND METHODS

We performed purposive sampling of 10 open operations. For each case, six providers (anesthesiology attending, in-room anesthetist, circulator, scrub, surgery attending, and surgery resident) were queried about the number of mutually shared cases. We identified communication events and created dyad-specific communication rates.

RESULTS

Analysis of 48 h of audio-video content identified 2570 communication events. Operations averaged 58.0 communication events per hour (range, 29.4-76.1). Familiarity was not associated with communication rate (P = 0.69) or communication ineffectiveness (P = 0.21). Cross-disciplinary dyads had lower communication rates than intradisciplinary dyads (P < 0.001). Anesthesiology-nursing, anesthesiology-surgery, and nursing-surgery dyad communication rates were 20.1%, 42.7%, and 57.3% the rate predicted from intradisciplinary dyads, respectively. In addition, cross-disciplinary dyad status was a significant predictor of having at least one ineffective communication event (P = 0.02).

CONCLUSIONS

Team members do not compensate for unfamiliarity by increasing their verbal communication, and dyad familiarity is not protective against ineffective communication. Cross-disciplinary communication remains vulnerable in the OR suggesting poor crosstalk across disciplines in the operative setting. Further investigation is needed to explore these relationships and identify effective interventions, ensuring that all team members have the necessary information to optimize their performance.

Development and evaluation of rhinoplasty spreader graft suture simulator for novice surgeons

OBJECTIVE

Surgical simulators aimed at mimicking elements of rhinoplasty surgery, specifically those aimed at improving cartilage suturing, are not available. Here, we present a surgical simulator for spreader graft placement that uses cartilage rather than synthetic materials and gauge improvement using objective measures for suture placement accuracy, speed, and efficiency of hand motion.

METHODS

Twenty-two otolaryngologists in two groups (residents [10] and experts [12]) were instructed to secure the two spreader graft specimen into position with three mattress sutures on a nose model that used porcine septal cartilage as a proxy for the human counterpart. Hand motion was tracked using an electromagnetic position sensing device. The time required to complete the suture task, total hand displacement, cumulative number of hand motion direction changes, and accuracy of suture insertion were measured. These measurements were compared between the two cohort groups for construct validity. The subjects completed a survey to evaluate realism and value of the model.

RESULTS

The expert group had a lower mean time required to complete the task (P < 0.05), total hand displacement (P < 0.01), and number of hand motion direction changes (P < 0.001). No significant difference was observed between the two groups in suture precision measurement. The subjects agreed on the face validity and usefulness of the trainer.

CONCLUSIONS

Our study suggests that the simulator may be a useful tool to objectively gauge suturing efficiency. Devices such as this may be useful for developing skill with suturing cartilage tissue and potentially be used to assess resident acquisition of surgical skill.

LEVEL OF EVIDENCE

NA Laryngoscope, 129:344-350, 2019.

Visualizing stressful aspects of repetitive motion tasks and opportunities for ergonomic improvements using computer vision

Patterns of physical stress exposure are often difficult to measure, and the metrics of variation and techniques for identifying them is underdeveloped in the practice of occupational ergonomics. Computer vision has previously been used for evaluating repetitive motion tasks for hand activity level (HAL) utilizing conventional 2D videos. The approach was made practical by relaxing the need for high precision, and by adopting a semi-automatic approach for measuring spatiotemporal characteristics of the repetitive task. In this paper, a new method for visualizing task factors, using this computer vision approach, is demonstrated. After videos are made, the analyst selects a region of interest on the hand to track and the hand location and its associated kinematics are measured for every frame. The visualization method spatially deconstructs and displays the frequency, speed and duty cycle components of tasks that are part of the threshold limit value for hand activity for the purpose of identifying patterns of exposure associated with the specific job factors, as well as for suggesting task improvements. The localized variables are plotted as a heat map superimposed over the video, and displayed in the context of the task being performed. Based on the intensity of the specific variables used to calculate HAL, we can determine which task factors most contribute to HAL, and readily identify those work elements in the task that contribute more to increased risk for an injury. Work simulations and actual industrial examples are described. This method should help practitioners more readily measure and interpret temporal exposure patterns and identify potential task improvements.

A marker-less technique for measuring kinematics in the operating room

BACKGROUND

Often in simulated settings, quantitative analysis of technical skill relies largely on specially tagged instruments or tracers on surgeons' hands. We investigated a novel, marker-less technique for evaluating technical skill during open operations and for differentiating tasks and surgeon experience level.

METHODS

We recorded the operative field via in-light camera for open operations. Sixteen cases yielded 138 video clips of suturing and tying tasks ≥5 seconds in duration. Video clips were categorized based on surgeon role (attending, resident) and task subtype (suturing tasks: body wall, bowel anastomosis, complex anastomosis; tying tasks: body wall, superficial tying, deep tying). We tracked a region of interest on the hand to generate kinematic data. Nested, multilevel modeling addressed the nonindependence of clips obtained from the same surgeon.

RESULTS

Interaction effects for suturing tasks were seen between role and task categories for average speed (P = .04), standard deviation of speed (P = .05), and average acceleration (P = .03). There were significant differences across task categories for standard deviation of acceleration (P = .02). Significant differences for tying tasks across task categories were observed for maximum speed (P = .02); standard deviation of speed (P = .04); and average (P = .02), maximum (P < .01), and standard deviation (P = .03) of acceleration.

CONCLUSION

We demonstrated the ability to detect kinematic differences in performance using marker-less tracking during open operative cases. Suturing task evaluation was most sensitive to differences in surgeon role and task category and may represent a scalable approach for providing quantitative feedback to surgeons about technical skill.

Working volume: validity evidence for a motion-based metric of surgical efficiency

BACKGROUND

The aim of this study was to evaluate working volume as a potential assessment metric for open surgical tasks.

METHODS

Surgical attendings (n = 6), residents (n = 4), and medical students (n = 5) performed a suturing task on simulated connective tissue (foam), artery (rubber balloon), and friable tissue (tissue paper). Using a motion tracking system, effective working volume was calculated for each hand. Repeated measures analysis of variance assessed differences in working volume by experience level, dominant and/or nondominant hand, and tissue type.

RESULTS

Analysis revealed a linear relationship between experience and working volume. Attendings had the smallest working volume, and students had the largest (P = .01). The 3-way interaction of experience level, hand, and material type showed attendings and residents maintained a similar working volume for dominant and nondominant hands for all tasks. In contrast, medical students' nondominant hand covered larger working volumes for the balloon and tissue paper materials (P < .05).

CONCLUSIONS

This study provides validity evidence for the use of working volume as a metric for open surgical skills. Working volume may provide a means for assessing surgical efficiency and the operative learning curve.

Electroencephalographic Monitoring of Brain Wave Activity During Laparoscopic Surgical Simulation to Measure Surgeon Concentration and Stress: Can the Student Become the Master?

PURPOSE

To measure gamma and alpha brain wave activity as a measurement of concentration and stress levels during surgical simulator performance of laparoscopic tasks to determine if expert surgeons have different brain activity patterns compared with intermediate and novice surgeons.

MATERIALS AND METHODS

After obtaining Institutional Review Board approval, 1st and 2nd year medical students, urology residents (PGY2-PGY5), and attending urologists from one institution were recruited. Participants were stratified by level of experience and performed laparoscopic tasks on the EDGE laparoscopic simulator. Subjects were evaluated for concentration and stress levels using the electroencephalography (EEG) data extracted from the MUSE(™) headband. The MUSE software developer kit (SDK) allowed quantification of gamma and alpha waves during each task. An analysis of variance was used to compare concentration and stress levels between groups.

RESULTS

A total of 19 participants were recruited for the study and stratified by surgical experience into novice, intermediate, and expert laparoscopy groups: 6 medical students, 9 urology residents, and 4 attending urologists, respectively. Concentration and stress were quantified by calculating the area under the curve of the gamma and alpha EEG wave tracings. Stress was significantly lower in the attending urologists compared with the residents and medical students during the laparoscopic suturing and trended toward significance in the peg transfer task (P = 0.0003, P = 0.069). Concentration was significantly higher in the expert group compared with the less experienced groups during both the peg and suture tasks (P = 0.036, P = 0.0039).

CONCLUSIONS

EEG brain activity in more experienced surgeons reveals a significant increase in concentration levels with a decrease in stress during simulated laparoscopic tasks compared with novices. This information may correlate with increased proficiency as well as provide objective feedback of progress along the learning curve with the MUSE SDK.

Advanced Engineering Technology for Measuring Performance

The demand for competency-based assessments in surgical training is growing. Use of advanced engineering technology for clinical skills assessment allows for objective measures of hands-on performance. Clinical performance can be assessed in several ways via quantification of an assessee's hand movements (motion tracking), direction of visual attention (eye tracking), levels of stress (physiologic marker measurements), and location and pressure of palpation (force measurements). Innovations in video recording technology and qualitative analysis tools allow for a combination of observer- and technology-based assessments. Overall the goal is to create better assessments of surgical performance with robust validity evidence.

Surgical ergonomics. Analysis of technical skills, simulation models and assessment methods

INTRODUCTION

Over the past two centuries the surgical profession has undergone a profound evolution in terms of efficiency and outcomes. Societal concerns in relation to quality assurance, patient safety and cost reduction have highlighted the issue of training expert surgeons. The core elements of a training model build on the basic foundations of gross and fine motor skills. In this paper we provide an analysis of the ergonomic principles involved and propose relevant training techniques. We have endeavored to provide both the trainer and trainee perspectives.

METHODS

This paper is structured into four sections: 1) Pre-operative preparation issues, 2) technical skills and instrument handling, 3) low fidelity simulation models and 4) discussion of current concepts in crew resource management, deliberate practice and assessment.

DISCUSSION

Rehearsal, warm-up and motivation-enhancing techniques aid concentration and focus. Appropriate posture, comprehension of ergonomic principles in relation to surgical instruments and utilisation of the non-dominant hand are essential skills to master. Low fidelity models can be used to achieve significant progress through the early stages of the learning curve. Deliberate practice and innate ability are complementary to each other and may be considered useful adjuncts to surgical skills development.

CONCLUSION

Safe medical care requires that complex patient interventions be performed by highly skilled operators supported by reliable teams. Surgical ergonomics lie at the heart of any training model that aims to produce professionals able to function as leaders of a patient safety oriented culture.

Design of vessel ligation simulator for deliberate practice

BACKGROUND

Surgical residents develop technical skills at variable rates, often based on random chance of cases encountered. One such skill is tying secure knots without exerting excessive force. This study describes the design of a simulator using a force sensor to measure instantaneous forces exerted on a blood vessel analog during vessel ligation and the development of expert-derived performance goals.

MATERIALS AND METHODS

Vessel ligations were performed on Silastic tubing at an offset from a Vernier Force Sensor. Nine experts (surgical faculty and senior residents) and 10 novices (junior residents) were recruited to each perform 10 vessel ligations (two square knots each) with two-handed and one-handed techniques. Internal consistency for the series of vessel ligations was tested with Cronbach alpha. Maximum forces exerted by novices and experts were compared using Student t-test.

RESULTS

Internal consistency across the 10 ligations on the simulator was excellent (Cronbach alpha = 0.91). The expert group on average exerted a significantly lower maximum force when compared with novices while performing two-handed (0.76 ± 0.39 N versus 1.12 ± 0.49 N, P < 0.01) and one-handed (0.84 ± 0.32 N versus 1.36 ± 0.44 N, P < 0.01) vessel ligations.

CONCLUSIONS

Although the expert group performed vessel ligations with significantly lower peak force than the novice group, there were novices who performed at the expert level. This is consistent with the conceptual framework of milestones and suggests that the skill of gentle knot-tying can be measured and develops at different chronologic levels of training in different individuals. This simulator can be used as part of a deliberate practice curriculum with instantaneous visual feedback.