Balazs I. Lengyel

Evaluation of colonoscopy technical skill levels by use of an objective kinematic-based system.

BACKGROUND Colonoscopy requires training and experience to ensure accuracy and safety. Currently, no objective, validated process exists to determine when an endoscopist has attained technical competence. Kinematics data describing movements of laparoscopic instruments have been used in surgical skill assessment to define expert surgical technique. We have developed a novel system to record kinematics data during colonoscopy and quantitatively assess colonoscopist performance. OBJECTIVE To use kinematic analysis of colonoscopy to quantitatively assess endoscopic technical performance. DESIGN Prospective cohort study. SETTING Tertiary-care academic medical center. POPULATION This study involved physicians who perform colonoscopy. INTERVENTION Application of a kinematics data collection system to colonoscopy evaluation. MAIN OUTCOME MEASUREMENTS Kinematics data, validated task load assessment instrument, and technical difficulty visual analog scale. RESULTS All 13 participants completed the colonoscopy to the terminal ileum on the standard colon model. Attending physicians reached the terminal ileum quicker than fellows (median time, 150.19 seconds vs 299.86 seconds; p<.01) with reduced path lengths for all 4 sensors, decreased flex (1.75 m vs 3.14 m; P=.03), smaller tip angulation, reduced absolute roll, and lower curvature of the endoscope. With performance of attending physicians serving as the expert reference standard, the mean kinematic score increased by 19.89 for each decrease in postgraduate year (P<.01). Overall, fellows experienced greater mental, physical, and temporal demand than did attending physicians. LIMITATION Small cohort size. CONCLUSION Kinematic data and score calculation appear useful in the evaluation of colonoscopy technical skill levels. The kinematic score appears to consistently vary by year of training. Because this assessment is nonsubjective, it may be an improvement over current methods for determination of competence. Ongoing studies are establishing benchmarks and characteristic profiles of skill groups based on kinematics data.

Real-time computed tomography-based augmented reality for natural orifice transluminal endoscopic surgery navigation.

Natural orifice transluminal endoscopic surgery (NOTES) is technically challenging owing to endoscopic short‐sighted visualization, excessive scope flexibility and lack of adequate instrumentation. Augmented reality may overcome these difficulties. This study tested whether an image registration system for NOTES procedures (IR‐NOTES) can facilitate navigation.

Laparoscopic cholecystectomy after a quarter century: why do we still convert?

BackgroundLaparoscopic cholecystectomy (LC) is the gold standard procedure for gallbladder removal. However, conversion to open surgery is sometimes needed. The factors underlying a surgeon’s decision to convert a laparoscopic case to an open case are complex and poorly understood. With decreasing experience in open cholecystectomy, this procedure is however no longer the “safe” alternative it once was. With such an impending paradigm shift, this study aimed to identify the main reasons for conversion and ultimately to develop guidelines to help reduce the conversion rates.MethodsUsing the National Surgical Quality Improvement Program (NSQIP) database and financial records, the authors retrospectively reviewed 1,193 cholecystectomies performed at their institution from 2002 to 2009 and identified 70 conversions. Two independent surgeons reviewed the operative notes and determined the reasons for conversion. The number of ports at the time and the extent of dissection before conversion were assessed and used to create new conversion categories. Hospital length of stay (LOS), 30-day complications, operative times and charges, and hospital charges were compared between the new groups.ResultsIn 91% of conversion cases, the conversion was elective. In 49% of these conversions, the number of ports was fewer than four. According to the new conversion categories, most conversions were performed after minimal or no attempt at dissection. There were no differences in LOS, complications, operating room charges, or hospital charges between categories. Of the six emergent conversions (9%), bleeding and concern about common bile duct (CBD) injury were the main reasons. One CBD injury occurred.ConclusionsIn 49% of the cases, conversion was performed without a genuine attempt at laparoscopic dissection. Considering this new insight into the circumstances of conversion, the authors recommend that surgeons make a genuine effort at a laparoscopic approach, as reflected by placing four ports and trying to elevate the gallbladder before converting a case to an open approach.

Development and initial validation of an endoscopic part-task training box

BACKGROUND AND STUDY AIMS There is currently no objective and validated methodology available to assess the progress of endoscopy trainees or to determine when technical competence has been achieved. The aims of the current study were to develop an endoscopic part-task simulator and to assess scoring system validity. METHODS Fundamental endoscopic skills were determined via kinematic analysis, literature review, and expert interviews. Simulator prototypes and scoring systems were developed to reflect these skills. Validity evidence for content, internal structure, and response process was evaluated. RESULTS The final training box consisted of five modules (knob control, torque, retroflexion, polypectomy, and navigation and loop reduction). A total of 5 minutes were permitted per module with extra points for early completion. Content validity index (CVI)-realism was 0.88, CVI-relevance was 1.00, and CVI-representativeness was 0.88, giving a composite CVI of 0.92. Overall, 82 % of participants considered the simulator to be capable of differentiating between ability levels, and 93 % thought the simulator should be used to assess ability prior to performing procedures in patients. Inter-item assessment revealed correlations from 0.67 to 0.93, suggesting that tasks were sufficiently correlated to assess the same underlying construct, with each task remaining independent. Each module represented 16.0 % - 26.1 % of the total score, suggesting that no module contributed disproportionately to the composite score. Average box scores were 272.6 and 284.4 (P = 0.94) when performed sequentially, and average score for all participants with proctor 1 was 297.6 and 308.1 with proctor 2 (P = 0.94), suggesting reproducibility and minimal error associated with test administration. CONCLUSION A part-task training box and scoring system were developed to assess fundamental endoscopic skills, and validity evidence regarding content, internal structure, and response process was demonstrated.

Image Registered Gastroscopic Ultrasound (IRGUS) in human subjects: a pilot study to assess feasibility

BACKGROUND AND STUDY AIMS Endoscopic ultrasound (EUS) is a complex procedure due to the subtleties of ultrasound interpretation, the small field of observation, and the uncertainty of probe position and orientation. Animal studies demonstrated that Image Registered Gastroscopic Ultrasound (IRGUS) is feasible and may be superior to conventional EUS in efficiency and image interpretation. This study explores whether these attributes of IRGUS will be evident in human subjects, with the aim of assessing the feasibility, effectiveness, and efficiency of IRGUS in patients with suspected pancreatic lesions. PATIENTS AND METHODS This was a prospective feasibility study at a tertiary care academic medical center in human patients with pancreatic lesions on computed tomography (CT) scan. Patients who were scheduled to undergo conventional EUS were randomly chosen to undergo their procedure with IRGUS. Main outcome measures included feasibility, ease of use, system function, validated task load (TLX) assessment instrument, and IRGUS experience questionnaire. RESULTS Five patients underwent IRGUS without complication. Localization of pancreatic lesions was accomplished efficiently and accurately (TLX temporal demand 3.7 %; TLX effort 8.6 %). Image synchronization and registration was accomplished in real time without procedure delay. The mean assessment score for endoscopist experience with IRGUS was positive (66.6 ± 29.4). Real-time display of CT images in the EUS plane and echoendoscope orientation were the most beneficial characteristics. CONCLUSIONS IRGUS appears feasible and safe in human subjects, and efficient and accurate at identification of probe position and image interpretation. IRGUS has the potential to broaden the adoption of EUS techniques and shorten EUS learning curves. Clinical studies comparing IRGUS with conventional EUS are ongoing.

Markov modeling of colonoscopy gestures to develop skill trainers

Colonoscopy is a complex procedure which requires considerable skill by the clinician in guiding the scope safely and accurately through the colon, and in a manner tolerable to the patient. Excessive pressure can cause the colon walls to distend, leading to excruciating pain or perforation. Concerted efforts by the ASGE have led to stipulating guidelines for trainees to reach necessary expertise. In this paper, we have analyzed the motion of the colonoscope by collecting kinematics data using 4 electromagnetic position sensors. Further, 36 feature vectors have been defined to capture all possible gestures. These feature vectors are used to train Hidden Markov Models to identify critical gestures that differentiate expertise. Five expert attending clinicians and four fellows were recruited as part of this study. Experimental results show that roll of the scope shows maximum differentiation of expertise.