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Papers by Erica Sutton

Background: Patients who sustain cervical spinal cord injury (C-SCI) with neurologic deficit may ... more Background: Patients who sustain cervical spinal cord injury (C-SCI) with neurologic deficit may require a definitive airway and/or prolonged mechanical ventilation. The purpose of this study was to characterize factors associated with a high risk for respiratory failure and/or the need for mechanical ventilation in C-SCI patients. Methods: Patients with C-SCI and neurologic deficit admitted to a Level I Trauma Center between July 1, 2000 and June 30, 2002 were retrospectively reviewed for demographics, level and completeness of neurologic deficit, need for definitive airway, need for tracheostomy, need for mechanical ventilation at hospital discharge (MVDC), and outcomes. The level and completeness of injury were defined by American Spinal Injury Association standards. Results: One hundred nineteen patients with C-SCI and neurologic deficit were identified over this period. Of these, 45 were identified as complete C-SCI: 12 (27%) patients had levels of C1 to C4; 19 (42%) had a level of C5; and 14 (31%) had levels of C6 and below. There were 37 males and 8 females. There were 36 blunt and 9 penetrating injuries. The average age of these patients was 40؉/-21, and the average ISS was 45؉/-22. Eight of the patients with complete C-SCI died, for a mortality of 18%. Of the 37 survivors, 92% received a definitive airway, 81% received tracheostomy, and 51% required MVDC. All patients with complete injuries at the C5 level and above required a definitive airway and tracheostomy, and 71% of survivors required MVDC. Of the patients with complete injuries of C6 and below, 79% received a definitive airway, 50% required tracheostomy, and 15% of survivors required MVDC. Only 35% of incomplete injuries required a definitive airway, and only 7% required tracheostomy. Conclusions: The need for definitive airway control, tracheostomy, and ventilator dependence is significant, especially for patients with high complete C-SCI. Based on these results we recommend consideration of early intubation and tracheostomy for patients with complete C-SCI, especially for those with levels of C5 and above.

The American surgeon, 2015

With the introduction of Fundamentals of Endoscopic Surgery™, training methods in flexible endosc... more With the introduction of Fundamentals of Endoscopic Surgery™, training methods in flexible endoscopy are being augmented with simulation-based curricula. The investment for virtual reality simulators warrants further research into its training advantage. Trainees were randomized into bedside or simulator training groups (BED vs SIM). SIM participated in a proficiency-based virtual reality curriculum. Trainees' endoscopic skills were rated using the Global Assessment of Gastrointestinal Endoscopic Skills (GAGES) in the patient care setting. The number of cases to reach 90 per cent of the maximum GAGES score and calculated costs of training were compared. Nineteen residents participated in the study. There was no difference in the average number of cases required to achieve 90 per cent of the maximum GAGES score for esophagogastroduodenoscopy, 13 (SIM) versus11 (BED) (P = 0.63), or colonoscopy 21 (SIM) versus 4 (BED) (P = 0.34). The average per case cost of training for esophagoga...

Surgical innovation, 2009

Surgeons and naval aviators are both trained to work in high-stakes environments. Any misadventur... more Surgeons and naval aviators are both trained to work in high-stakes environments. Any misadventure in either of their working worlds can lead to death. Yet the pathways to certification and implicit attitudes toward training are quite different in these 2 disciplines and provide an opportunity to compare and contrast the methodologies employed. At the 5th annual Innovations in the Surgical Environments Conference, senior and junior aviators and surgeons shared their experiences from the perspective of trainee and trainer and in the process presented an interesting study in parallels and contrasts. The US Navy follows a highly regimented training syllabus with graduated levels of responsibility designed to create the safest possible flying environment. Extensive preflight and postflight effort is required for each mission flown. Surgical training is also hierarchal in responsibility, but graduates demonstrate greater variability in their training experience. The surgical field can on...

Journal of surgical education

2010 11th International Conference on Control Automation Robotics & Vision, 2010

Current generation minimally invasive surgeries present many visualization challenges, including ... more Current generation minimally invasive surgeries present many visualization challenges, including two-dimensional representation of three-dimensional anatomy and a lack of visualization of deeply recessed structures. Coupled with the loss of tactile feedback which places greater emphasis on available visual cues, improved surgical visualization remains a long-standing need. Our response to address this need is Live Augmented Reality (Live AR), in which

Surgical Endoscopy and Other Interventional Techniques, 2011

Background Minimally invasive surgery requires highquality imaging to provide effective visual di... more Background Minimally invasive surgery requires highquality imaging to provide effective visual displays to surgeons. Whereas objective measures-pixels, resolution, display size, contrast ratio-are used to compare imaging systems, there are no tools for assessing the perceptual impact of these physical measures. We developed the ''Maryland Visual Comfort Scale'' (MVCS) to measure perceptual qualities in relation to an imaging system. We theorize that what the surgeon perceives as a high-quality image can be summarized by a scoring of seven characteristics related to human perception, and that image quality is not homogenous across a video display such that object location impacts perception and display quality. Method We created a rating scale for seven dimensions of display characteristics (contrast, detail, brightness, lighting uniformity, focus uniformity, color, sharpness). For validation, 30 participants viewed test patterns and manipulated physiologic images, rating the image quality for all seven dimensions as well as giving an overall rating. Image ratings for contrast and detail dimensions were assessed across five locations on the video display. For ratings, two imaging systems were used, differing primarily in the 10-mm zero-degree scope's quality: a standard scope and one taken from service for quality degradation. Results The rating scale was sensitive to differences in scope quality for all seven items in the MVCS (all p values \ 0.01). Significant differences existed between quality ratings at central and peripheral locations (p \ 0.05). Conclusions This seven-item rating scale for assessing visual comfort is reliable and sensitive to scope quality differences. The scale is sensitive to degradation of image quality at video display edges. These seven dimensions of display characteristics can be refined to create a psychometric to serve as a composite of perceptual quality in laparoscopy.

The American Journal of Surgery, 2011

the role of simulation for training in procedures such as laparoscopic incisional hernia repair (... more the role of simulation for training in procedures such as laparoscopic incisional hernia repair (LIHR) is unknown. The purpose of this study was to determine whether performance in simulated LIHR correlates with operating room (OR) performance. subjects performed LIHR in the University of Maryland Surgical Abdominal Wall (SAW) simulator and the OR. Trained observers used a LIHR-specific global rating scale (Global Operative Assessment of Laparoscopic Skills-Incisional Hernia) to assess performance. Global Operative Assessment of Laparoscopic Skills-Incisional Hernia includes 7 domains (trocar placement, adhesiolysis, mesh sizing, mesh positioning, mesh fixation, knowledge and autonomy in instrument use, and overall competence). The correlation between simulator and OR performance was assessed using the Pearson coefficient. fourteen surgeons from 2 surgical departments participated. Experienced surgeons (n = 9) were defined as attending surgeons and minimally invasive surgury (MIS) fellows, and novice surgeons (n = 5) were general surgery residents (postgraduate years 3-5). The correlation between performance in the OR and the simulator for the entire group was .87 (95% confidence interval, .63-.96; P < .001). there was an excellent correlation between LIHR performance in the simulator and clinical LIHR. This suggests that performance in the SAW simulator may predict performance in the operating room.

Surgical Endoscopy, 2014

Background Among surgeons who regularly perform minimally invasive surgery, as many as 87 % repor... more Background Among surgeons who regularly perform minimally invasive surgery, as many as 87 % report injuries or symptoms related to job performance. Operating room and instrument design have traditionally favored surgeons who are taller and who possess hands that are, in general, large and strong. We hypothesize that women may be experiencing more ergonomic difficulties than men for whom the operating room and surgical instruments, although uniformly perilous, more traditionally have accommodated. Methods A 23-item web-based survey was offered via email to 2,000 laparoscopic surgeons and fellows currently practicing. The survey addressed four categories: demographics, physical symptoms, ergonomics, and environment/equipment. Key questions allowed us to identify which body part experienced which symptoms. Results There was a 15.7 % overall response rate. Among respondents, 17 % (54/314) were female. Women were significantly younger, shorter, had smaller glove size, and fewer years in practice than men surveyed (all p values \ 0.0001). Of women reporting, 86.5 %-comparable to men-attribute physical discomfort to laparoscopic operating. Female surgeons are more likely to receive treatment for their hands, which includes the wrist, thumb, and fingers (odds ratio 3.5, p = 0.028). When men and women of the same glove size were compared, women with a larger glove size (7-8.5) reported more cases of treatment for their hands than men of the same glove size. (21 vs. 3 %, p = 0.016). Women who wore a size 5.5-6.5 surgical glove reported significantly more cases of discomfort in their shoulder area (neck, shoulder, upper back) than men who wore the same size surgical glove (77 vs. 27 %, p = 0.004). Conclusions Women surgeons are experiencing more discomfort and treatment in their hands than male surgeons. Redesign of laparoscopic instrument handles and improvements to table height comprise the most promising solutions to these ergonomic challenges.

Surgical Endoscopy, 2011

Background This study compares surgical techniques and surgeon's standing position during laparos... more Background This study compares surgical techniques and surgeon's standing position during laparoscopic cholecystectomy (LC), investigating each with respect to surgeons' learning, performance, and ergonomics. Little homogeneity exists in LC performance and training. Variations in standing position (side-standing technique vs. betweenstanding technique) and hand technique (one-handed vs. two-handed) exist. Methods Thirty-two LC procedures performed on a virtual reality simulator were video-recorded and analyzed. Each subject performed four different procedures: onehanded/side-standing, one-handed/between-standing, twohanded/side-standing, and two-handed/between-standing. Physical ergonomics were evaluated using Rapid Upper Limb Assessment (RULA). Mental workload assessment was acquired with the National Aeronautics and Space Administration-Task Load Index (NASA-TLX). Virtual reality (VR) simulator-generated performance evaluation and a subjective survey were analyzed. Results RULA scores were consistently lower (indicating better ergonomics) for the between-standing technique and higher (indicating worse ergonomics) for the side-standing technique, regardless of whether one-or two-handed. Anatomical scores overall showed side-standing to have a detrimental effect on the upper arms and trunk. The NASA-TLX showed significant association between the sidestanding position and high physical demand, effort, and frustration (p \ 0.05). The two-handed technique in the side-standing position required more effort than the onehanded (p \ 0.05). No difference in operative time or complication rate was demonstrated among the four procedures. The two-handed/between-standing method was chosen as the best procedure to teach and standardize. Conclusions Laparoscopic cholecystectomy poses a risk of physical injury to the surgeon. As LC is currently commonly performed in the United States, the left side-standing position may lead to increased physical demand and effort, resulting in ergonomically unsound conditions for the surgeon. Though further investigations should be conducted, adopting the between-standing position deserves serious consideration as it may be the best short-term ergonomic alternative.

Surgical Endoscopy, 2014

Background We conducted this study to investigate how physical and cognitive ergonomic workloads ... more Background We conducted this study to investigate how physical and cognitive ergonomic workloads would differ between robotic and laparoscopic surgeries and whether any ergonomic differences would be related to surgeons' robotic surgery skill level. Our hypothesis is that the unique features in robotic surgery will demonstrate skill-related results both in substantially less physical and cognitive workload and uncompromised task performance. Methods Thirteen MIS surgeons were recruited for this institutional review board-approved study and divided into three groups based on their robotic surgery experiences: laparoscopy experts with no robotic experience, novices with no or little robotic experience, and robotic experts. Each participant performed six surgical training tasks using traditional laparoscopy and robotic surgery. Physical workload was assessed by using surface electromyography from eight muscles (biceps, triceps, deltoid, trapezius, flexor carpi ulnaris, extensor digitorum, thenar compartment, and erector spinae). Mental workload assessment was conducted using the NASA-TLX. Results The cumulative muscular workload (CMW) from the biceps and the flexor carpi ulnaris with robotic surgery was significantly lower than with laparoscopy (p \ 0.05). Interestingly, the CMW from the trapezius was significantly higher with robotic surgery than with laparoscopy (p \ 0.05), but this difference was only observed in laparoscopic experts (LEs) and robotic surgery novices. NASA-TLX analysis showed that both robotic surgery novices and experts expressed lower global workloads with robotic surgery than with laparoscopy, whereas LEs showed higher global workload with robotic surgery (p [ 0.05). Robotic surgery experts and novices had significantly higher performance scores with robotic surgery than with laparoscopy (p \ 0.05). Conclusions This study demonstrated that the physical and cognitive ergonomics with robotic surgery were significantly less challenging. Additionally, several ergonomic components were skill-related. Robotic experts could benefit the most from the ergonomic advantages in robotic surgery. These results emphasize the need for well-structured training and well-defined ergonomics guidelines to maximize the benefits utilizing the robotic surgery.

Surgical Endoscopy, 2010

Disruptions to surgical workflow have been correlated with an increase in surgical errors and sub... more Disruptions to surgical workflow have been correlated with an increase in surgical errors and suboptimal outcomes in patient safety measures. Yet, our ability to quantify such threats to patient safety remains inadequate. Data are needed to gauge how the laparoscopic operating room work environment, where the visual and motor axes are no longer aligned, contributes to such disruptions. We used time motion analysis techniques to measure surgeon attention during laparoscopic cholecystectomy in order to characterize disruptive events imposed by the work environment of the OR. In this investigation we identify attention disruptions as they occur in terms of the operating surgeon's gaze. We then quantify such disruptions and also seek to establish what occasioned them. Ten laparoscopic cholecystectomy procedures were recorded with both intra- and extracorporeal cameras. The views were synchronized to produce a video that was subsequently analyzed by a single independent observer. Each time the surgeon's gaze was diverted from the operation's video display, the event was recorded via time-stamp. The reason for looking away (e.g., instrument exchange), when discernable, was also recorded and categorized. Disruptions were then reviewed and analyzed by an interdisciplinary team of surgeons and human factors experts. Gaze disruptions were classified into one of four causal categories: instrument exchange, extracorporeal work, equipment troubleshooting, and communication. On average, 40 breaks occurred in operating surgeon attention per 15 min of operating time. The most frequent reasons for these disruptions involved instrument exchange (38%) and downward gaze for extracorporeal work (28%). This study of laparoscopic cholecystectomy performance reveals a high gaze disruption rate in the current operating room work environment. Improvements aimed at reducing such disruptions-and thus potentially surgical error-should center on better instrument design and realigning the axis between surgeon's eye and visual display.

Surgical Endoscopy, 2011

Background Research confirms that surgeons experience physical symptoms due to the unfavorable er... more Background Research confirms that surgeons experience physical symptoms due to the unfavorable ergonomics of laparoscopy. The physical effects of performing Natural Orifice Transluminal Endoscopic Surgery (NOTES)potentially the next evolutionary surgical step-are only now being quantitatively and systematically assessed. This study investigates NOTES-and laparoscopy-related physical workloads through biomechanical analyses. Methods Fourteen surgeons with varying laparoscopic experience were recruited. Each participant completed ring transfer and triangle transfer tasks using two surgical platforms: laparoscopy and NOTES. Motion capture and electromyography (EMG) systems recorded biomechanical data for quantitative physical workload assessment. The normalized cumulative muscular workload (NCMW) and mean muscular workload (MMW) were obtained from EMG data. Then normalized performance time (NPT) was compared between the two surgical platforms. The overall NCMW was considerably greater when participants performed tasks using the NOTES platform (1315.8 ± 116.9%) compared with traditional laparoscopy (153.9 ± 18.8%). Results Performing NOTES required eight to nine times higher muscular workload (NCMW: NOTES 1315.8%, laparoscopy 153.9%, p \ 0.05) when compared with traditional laparoscopy. This result was shown to be caused by the following: (1) six to eight times longer NPT with NOTES (p \ 0.05) and (2) higher average activation levels shown in regard to biceps, extensor digitorum communis, and thenar compartment (p \ 0.05), the muscles responsible for specific joint movements to hold and operate the scope. Conclusion This study demonstrated that performing NOTES is significantly more challenging for surgeons than laparoscopy. The greater amount of muscular exertion required is linked to higher ergonomic risks. Based on the depth and strength of our results, we propose that an alternative NOTES platform be designed, one that overcomes the awkward operational mechanism of the dualworking-channel flexible endoscope.

Surgical Endoscopy, 2010

Current laparoscopic images are rich in surface detail but lack information on deeper structures.... more Current laparoscopic images are rich in surface detail but lack information on deeper structures. This report presents a novel method for highlighting these structures during laparoscopic surgery using continuous multislice computed tomography (CT). This has resulted in a more accurate augmented reality (AR) approach, termed "live AR," which merges three-dimensional (3D) anatomy from live low-dose intraoperative CT with live images from the laparoscope. A series of procedures with swine was conducted in a CT room with a fully equipped laparoscopic surgical suite. A 64-slice CT scanner was used to image the surgical field approximately once per second. The procedures began with a contrast-enhanced, diagnostic-quality CT scan (initial CT) of the liver followed by continuous intraoperative CT and laparoscopic imaging with an optically tracked laparoscope. Intraoperative anatomic changes included user-applied deformations and those from breathing. Through deformable image registration, an intermediate image processing step, the initial CT was warped to align spatially with the low-dose intraoperative CT scans. The registered initial CT then was rendered and merged with laparoscopic images to create live AR. Superior compensation for soft tissue deformations using the described method led to more accurate spatial registration between laparoscopic and rendered CT images with live AR than with conventional AR. Moreover, substitution of low-dose CT with registered initial CT helped with continuous visualization of the vasculature and offered the potential of at least an eightfold reduction in intraoperative X-ray dose. The authors proposed and developed live AR, a new surgical visualization approach that merges rich surface detail from a laparoscope with instantaneous 3D anatomy from continuous CT scanning of the surgical field. Through innovative use of deformable image registration, they also demonstrated the feasibility of continuous visualization of the vasculature and considerable X-ray dose reduction. This study provides motivation for further investigation and development of live AR.

Surgical Endoscopy, 2011

Laparoscopic incisional hernia repair (LIHR) is a common procedure requiring advanced laparoscopi... more Laparoscopic incisional hernia repair (LIHR) is a common procedure requiring advanced laparoscopic skills. This study aimed to develop a procedure-specific tool to assess the performance of LIHR and to evaluate its reliability and validity. The Global Operative Assessment of Laparoscopic Skills-Incisional Hernia (GOALS-IH) is a 7-item global rating scale developed by experts to evaluate the steps of LIHR (placement of trocars, adhesiolysis, estimation of mesh size and shape, mesh orientation and positioning, mesh fixation, knowledge and autonomy in use of instruments, overall competence), each rated on a 5-point Likert scale. During LIHR, 13 attending surgeons and fellows experienced in minimally invasive surgery (MIS) and 19 novice surgeons (postgraduate years [PGYs], 3-5) were evaluated at four teaching hospitals by the attending surgeon, a trained observer, and self-assessment using GOALS-IH, and by a previously validated 5-item general laparoscopic rating scale (GOALS). Interrater reliability was assessed by intraclass correlation (ICC), and internal consistency of rating items was assessed by Cronbach's alpha. Known-groups construct validity was assessed by using the t-test and by correlating of the number of self-reported LIHR cases with the total score. Concurrent validity was assessed by correlating the GOALS-IH score with the GOALS general rating scale. Data are presented as mean and 95% confidence interval (CI). Interrater reliability for the total GOALS-IH score was 0.79 (95% CI, 0.60-0.89) between observers and attending surgeons, 0.81 (95% CI, 0.58-0.92) between participants and attending surgeons, and 0.89 (95% CI, 0.76-0.96) between participants and observers. Internal consistency was high (Cronbach's alpha, 0.93). Experienced surgeons performed significantly better than novices as assessed by GOALS-IH (31; 95% CI, 29-33 vs. 21; 95% CI, 19-24; p < 0.01). Very good correlation was found between GOALS-IH and previous LIHR experience (r = 0.82; p < 0.01) and strong correlation between GOALS-IH and generic GOALS total scores (r = 0.90; p < 0.01). Surgical performance during clinical LIHR can be assessed reliably using GOALS-IH. Results can be used to provide formative feedback to the surgeon and to identify steps of the operation that would benefit from specific educational interventions.

Journal of Surgical Education, 2010

Journal of Gastrointestinal Surgery, 2012

Laparoscopic repair of a giant paraesophageal hiatal hernia remains a challenging procedure. Seve... more Laparoscopic repair of a giant paraesophageal hiatal hernia remains a challenging procedure. Several techniques have been developed in efforts to achieve tension-free reconstruction of the esophageal hiatus. In this report, we describe a technique whereby the falciform ligament is used as an autologous onlay flap to achieve tension-free closure of the crural defect of a giant paraesophageal hernia (GPEH). Use of the falciform ligament as a vascularized autologous onlay flap is a safe and effective procedure to obtain closure of the crural defect of a GPEH. The falciform ligament should be adequately mobilized from the anterior abdominal wall to prevent lateral tension on the flap, but care must be taken to avoid devascularization. Interrupted vertical mattress sutures are used to fix the falciform ligament to the left and right hiatal crurae.

The American surgeon, 2013

Virtual reality (VR) simulators may hold a role in the assessment of trainee abilities independen... more Virtual reality (VR) simulators may hold a role in the assessment of trainee abilities independent of their role as instructional instruments. Thus, we piloted a course in flexible endoscopy to surgical trainees who had met Accreditation Council for Graduate Medical Education endoscopy requirements to establish the relationship between metrics produced by a VR endoscopic simulator and trainee ability. After a didactic session, we provided faculty instruction to senior residents for Case 1 upper endoscopy and colonoscopy modules on the CAE EndoscopyVR. Course conclusion was defined as a trainee meeting all proficiency standards in basic endoscopic procedures on the simulator. Simulator metrics and course evaluation comprised data. Eleven and eight residents participated in the colonoscopy and upper endoscopy courses, respectively. Average time to reach proficiency standards for esophagogastroduodenoscopy was 6 and 13 minutes for colonoscopy after a median of one (range, one to two) a...

Background: Patients who sustain cervical spinal cord injury (C-SCI) with neurologic deficit may ... more Background: Patients who sustain cervical spinal cord injury (C-SCI) with neurologic deficit may require a definitive airway and/or prolonged mechanical ventilation. The purpose of this study was to characterize factors associated with a high risk for respiratory failure and/or the need for mechanical ventilation in C-SCI patients. Methods: Patients with C-SCI and neurologic deficit admitted to a Level I Trauma Center between July 1, 2000 and June 30, 2002 were retrospectively reviewed for demographics, level and completeness of neurologic deficit, need for definitive airway, need for tracheostomy, need for mechanical ventilation at hospital discharge (MVDC), and outcomes. The level and completeness of injury were defined by American Spinal Injury Association standards. Results: One hundred nineteen patients with C-SCI and neurologic deficit were identified over this period. Of these, 45 were identified as complete C-SCI: 12 (27%) patients had levels of C1 to C4; 19 (42%) had a level of C5; and 14 (31%) had levels of C6 and below. There were 37 males and 8 females. There were 36 blunt and 9 penetrating injuries. The average age of these patients was 40؉/-21, and the average ISS was 45؉/-22. Eight of the patients with complete C-SCI died, for a mortality of 18%. Of the 37 survivors, 92% received a definitive airway, 81% received tracheostomy, and 51% required MVDC. All patients with complete injuries at the C5 level and above required a definitive airway and tracheostomy, and 71% of survivors required MVDC. Of the patients with complete injuries of C6 and below, 79% received a definitive airway, 50% required tracheostomy, and 15% of survivors required MVDC. Only 35% of incomplete injuries required a definitive airway, and only 7% required tracheostomy. Conclusions: The need for definitive airway control, tracheostomy, and ventilator dependence is significant, especially for patients with high complete C-SCI. Based on these results we recommend consideration of early intubation and tracheostomy for patients with complete C-SCI, especially for those with levels of C5 and above.

The American surgeon, 2015

With the introduction of Fundamentals of Endoscopic Surgery™, training methods in flexible endosc... more With the introduction of Fundamentals of Endoscopic Surgery™, training methods in flexible endoscopy are being augmented with simulation-based curricula. The investment for virtual reality simulators warrants further research into its training advantage. Trainees were randomized into bedside or simulator training groups (BED vs SIM). SIM participated in a proficiency-based virtual reality curriculum. Trainees' endoscopic skills were rated using the Global Assessment of Gastrointestinal Endoscopic Skills (GAGES) in the patient care setting. The number of cases to reach 90 per cent of the maximum GAGES score and calculated costs of training were compared. Nineteen residents participated in the study. There was no difference in the average number of cases required to achieve 90 per cent of the maximum GAGES score for esophagogastroduodenoscopy, 13 (SIM) versus11 (BED) (P = 0.63), or colonoscopy 21 (SIM) versus 4 (BED) (P = 0.34). The average per case cost of training for esophagoga...

Surgical innovation, 2009

Surgeons and naval aviators are both trained to work in high-stakes environments. Any misadventur... more Surgeons and naval aviators are both trained to work in high-stakes environments. Any misadventure in either of their working worlds can lead to death. Yet the pathways to certification and implicit attitudes toward training are quite different in these 2 disciplines and provide an opportunity to compare and contrast the methodologies employed. At the 5th annual Innovations in the Surgical Environments Conference, senior and junior aviators and surgeons shared their experiences from the perspective of trainee and trainer and in the process presented an interesting study in parallels and contrasts. The US Navy follows a highly regimented training syllabus with graduated levels of responsibility designed to create the safest possible flying environment. Extensive preflight and postflight effort is required for each mission flown. Surgical training is also hierarchal in responsibility, but graduates demonstrate greater variability in their training experience. The surgical field can on...

Journal of surgical education

2010 11th International Conference on Control Automation Robotics & Vision, 2010

Current generation minimally invasive surgeries present many visualization challenges, including ... more Current generation minimally invasive surgeries present many visualization challenges, including two-dimensional representation of three-dimensional anatomy and a lack of visualization of deeply recessed structures. Coupled with the loss of tactile feedback which places greater emphasis on available visual cues, improved surgical visualization remains a long-standing need. Our response to address this need is Live Augmented Reality (Live AR), in which

Surgical Endoscopy and Other Interventional Techniques, 2011

Background Minimally invasive surgery requires highquality imaging to provide effective visual di... more Background Minimally invasive surgery requires highquality imaging to provide effective visual displays to surgeons. Whereas objective measures-pixels, resolution, display size, contrast ratio-are used to compare imaging systems, there are no tools for assessing the perceptual impact of these physical measures. We developed the ''Maryland Visual Comfort Scale'' (MVCS) to measure perceptual qualities in relation to an imaging system. We theorize that what the surgeon perceives as a high-quality image can be summarized by a scoring of seven characteristics related to human perception, and that image quality is not homogenous across a video display such that object location impacts perception and display quality. Method We created a rating scale for seven dimensions of display characteristics (contrast, detail, brightness, lighting uniformity, focus uniformity, color, sharpness). For validation, 30 participants viewed test patterns and manipulated physiologic images, rating the image quality for all seven dimensions as well as giving an overall rating. Image ratings for contrast and detail dimensions were assessed across five locations on the video display. For ratings, two imaging systems were used, differing primarily in the 10-mm zero-degree scope's quality: a standard scope and one taken from service for quality degradation. Results The rating scale was sensitive to differences in scope quality for all seven items in the MVCS (all p values \ 0.01). Significant differences existed between quality ratings at central and peripheral locations (p \ 0.05). Conclusions This seven-item rating scale for assessing visual comfort is reliable and sensitive to scope quality differences. The scale is sensitive to degradation of image quality at video display edges. These seven dimensions of display characteristics can be refined to create a psychometric to serve as a composite of perceptual quality in laparoscopy.

The American Journal of Surgery, 2011

the role of simulation for training in procedures such as laparoscopic incisional hernia repair (... more the role of simulation for training in procedures such as laparoscopic incisional hernia repair (LIHR) is unknown. The purpose of this study was to determine whether performance in simulated LIHR correlates with operating room (OR) performance. subjects performed LIHR in the University of Maryland Surgical Abdominal Wall (SAW) simulator and the OR. Trained observers used a LIHR-specific global rating scale (Global Operative Assessment of Laparoscopic Skills-Incisional Hernia) to assess performance. Global Operative Assessment of Laparoscopic Skills-Incisional Hernia includes 7 domains (trocar placement, adhesiolysis, mesh sizing, mesh positioning, mesh fixation, knowledge and autonomy in instrument use, and overall competence). The correlation between simulator and OR performance was assessed using the Pearson coefficient. fourteen surgeons from 2 surgical departments participated. Experienced surgeons (n = 9) were defined as attending surgeons and minimally invasive surgury (MIS) fellows, and novice surgeons (n = 5) were general surgery residents (postgraduate years 3-5). The correlation between performance in the OR and the simulator for the entire group was .87 (95% confidence interval, .63-.96; P < .001). there was an excellent correlation between LIHR performance in the simulator and clinical LIHR. This suggests that performance in the SAW simulator may predict performance in the operating room.

Surgical Endoscopy, 2014

Background Among surgeons who regularly perform minimally invasive surgery, as many as 87 % repor... more Background Among surgeons who regularly perform minimally invasive surgery, as many as 87 % report injuries or symptoms related to job performance. Operating room and instrument design have traditionally favored surgeons who are taller and who possess hands that are, in general, large and strong. We hypothesize that women may be experiencing more ergonomic difficulties than men for whom the operating room and surgical instruments, although uniformly perilous, more traditionally have accommodated. Methods A 23-item web-based survey was offered via email to 2,000 laparoscopic surgeons and fellows currently practicing. The survey addressed four categories: demographics, physical symptoms, ergonomics, and environment/equipment. Key questions allowed us to identify which body part experienced which symptoms. Results There was a 15.7 % overall response rate. Among respondents, 17 % (54/314) were female. Women were significantly younger, shorter, had smaller glove size, and fewer years in practice than men surveyed (all p values \ 0.0001). Of women reporting, 86.5 %-comparable to men-attribute physical discomfort to laparoscopic operating. Female surgeons are more likely to receive treatment for their hands, which includes the wrist, thumb, and fingers (odds ratio 3.5, p = 0.028). When men and women of the same glove size were compared, women with a larger glove size (7-8.5) reported more cases of treatment for their hands than men of the same glove size. (21 vs. 3 %, p = 0.016). Women who wore a size 5.5-6.5 surgical glove reported significantly more cases of discomfort in their shoulder area (neck, shoulder, upper back) than men who wore the same size surgical glove (77 vs. 27 %, p = 0.004). Conclusions Women surgeons are experiencing more discomfort and treatment in their hands than male surgeons. Redesign of laparoscopic instrument handles and improvements to table height comprise the most promising solutions to these ergonomic challenges.

Surgical Endoscopy, 2011

Background This study compares surgical techniques and surgeon's standing position during laparos... more Background This study compares surgical techniques and surgeon's standing position during laparoscopic cholecystectomy (LC), investigating each with respect to surgeons' learning, performance, and ergonomics. Little homogeneity exists in LC performance and training. Variations in standing position (side-standing technique vs. betweenstanding technique) and hand technique (one-handed vs. two-handed) exist. Methods Thirty-two LC procedures performed on a virtual reality simulator were video-recorded and analyzed. Each subject performed four different procedures: onehanded/side-standing, one-handed/between-standing, twohanded/side-standing, and two-handed/between-standing. Physical ergonomics were evaluated using Rapid Upper Limb Assessment (RULA). Mental workload assessment was acquired with the National Aeronautics and Space Administration-Task Load Index (NASA-TLX). Virtual reality (VR) simulator-generated performance evaluation and a subjective survey were analyzed. Results RULA scores were consistently lower (indicating better ergonomics) for the between-standing technique and higher (indicating worse ergonomics) for the side-standing technique, regardless of whether one-or two-handed. Anatomical scores overall showed side-standing to have a detrimental effect on the upper arms and trunk. The NASA-TLX showed significant association between the sidestanding position and high physical demand, effort, and frustration (p \ 0.05). The two-handed technique in the side-standing position required more effort than the onehanded (p \ 0.05). No difference in operative time or complication rate was demonstrated among the four procedures. The two-handed/between-standing method was chosen as the best procedure to teach and standardize. Conclusions Laparoscopic cholecystectomy poses a risk of physical injury to the surgeon. As LC is currently commonly performed in the United States, the left side-standing position may lead to increased physical demand and effort, resulting in ergonomically unsound conditions for the surgeon. Though further investigations should be conducted, adopting the between-standing position deserves serious consideration as it may be the best short-term ergonomic alternative.

Surgical Endoscopy, 2014

Background We conducted this study to investigate how physical and cognitive ergonomic workloads ... more Background We conducted this study to investigate how physical and cognitive ergonomic workloads would differ between robotic and laparoscopic surgeries and whether any ergonomic differences would be related to surgeons' robotic surgery skill level. Our hypothesis is that the unique features in robotic surgery will demonstrate skill-related results both in substantially less physical and cognitive workload and uncompromised task performance. Methods Thirteen MIS surgeons were recruited for this institutional review board-approved study and divided into three groups based on their robotic surgery experiences: laparoscopy experts with no robotic experience, novices with no or little robotic experience, and robotic experts. Each participant performed six surgical training tasks using traditional laparoscopy and robotic surgery. Physical workload was assessed by using surface electromyography from eight muscles (biceps, triceps, deltoid, trapezius, flexor carpi ulnaris, extensor digitorum, thenar compartment, and erector spinae). Mental workload assessment was conducted using the NASA-TLX. Results The cumulative muscular workload (CMW) from the biceps and the flexor carpi ulnaris with robotic surgery was significantly lower than with laparoscopy (p \ 0.05). Interestingly, the CMW from the trapezius was significantly higher with robotic surgery than with laparoscopy (p \ 0.05), but this difference was only observed in laparoscopic experts (LEs) and robotic surgery novices. NASA-TLX analysis showed that both robotic surgery novices and experts expressed lower global workloads with robotic surgery than with laparoscopy, whereas LEs showed higher global workload with robotic surgery (p [ 0.05). Robotic surgery experts and novices had significantly higher performance scores with robotic surgery than with laparoscopy (p \ 0.05). Conclusions This study demonstrated that the physical and cognitive ergonomics with robotic surgery were significantly less challenging. Additionally, several ergonomic components were skill-related. Robotic experts could benefit the most from the ergonomic advantages in robotic surgery. These results emphasize the need for well-structured training and well-defined ergonomics guidelines to maximize the benefits utilizing the robotic surgery.

Surgical Endoscopy, 2010

Disruptions to surgical workflow have been correlated with an increase in surgical errors and sub... more Disruptions to surgical workflow have been correlated with an increase in surgical errors and suboptimal outcomes in patient safety measures. Yet, our ability to quantify such threats to patient safety remains inadequate. Data are needed to gauge how the laparoscopic operating room work environment, where the visual and motor axes are no longer aligned, contributes to such disruptions. We used time motion analysis techniques to measure surgeon attention during laparoscopic cholecystectomy in order to characterize disruptive events imposed by the work environment of the OR. In this investigation we identify attention disruptions as they occur in terms of the operating surgeon's gaze. We then quantify such disruptions and also seek to establish what occasioned them. Ten laparoscopic cholecystectomy procedures were recorded with both intra- and extracorporeal cameras. The views were synchronized to produce a video that was subsequently analyzed by a single independent observer. Each time the surgeon's gaze was diverted from the operation's video display, the event was recorded via time-stamp. The reason for looking away (e.g., instrument exchange), when discernable, was also recorded and categorized. Disruptions were then reviewed and analyzed by an interdisciplinary team of surgeons and human factors experts. Gaze disruptions were classified into one of four causal categories: instrument exchange, extracorporeal work, equipment troubleshooting, and communication. On average, 40 breaks occurred in operating surgeon attention per 15 min of operating time. The most frequent reasons for these disruptions involved instrument exchange (38%) and downward gaze for extracorporeal work (28%). This study of laparoscopic cholecystectomy performance reveals a high gaze disruption rate in the current operating room work environment. Improvements aimed at reducing such disruptions-and thus potentially surgical error-should center on better instrument design and realigning the axis between surgeon's eye and visual display.

Surgical Endoscopy, 2011

Background Research confirms that surgeons experience physical symptoms due to the unfavorable er... more Background Research confirms that surgeons experience physical symptoms due to the unfavorable ergonomics of laparoscopy. The physical effects of performing Natural Orifice Transluminal Endoscopic Surgery (NOTES)potentially the next evolutionary surgical step-are only now being quantitatively and systematically assessed. This study investigates NOTES-and laparoscopy-related physical workloads through biomechanical analyses. Methods Fourteen surgeons with varying laparoscopic experience were recruited. Each participant completed ring transfer and triangle transfer tasks using two surgical platforms: laparoscopy and NOTES. Motion capture and electromyography (EMG) systems recorded biomechanical data for quantitative physical workload assessment. The normalized cumulative muscular workload (NCMW) and mean muscular workload (MMW) were obtained from EMG data. Then normalized performance time (NPT) was compared between the two surgical platforms. The overall NCMW was considerably greater when participants performed tasks using the NOTES platform (1315.8 ± 116.9%) compared with traditional laparoscopy (153.9 ± 18.8%). Results Performing NOTES required eight to nine times higher muscular workload (NCMW: NOTES 1315.8%, laparoscopy 153.9%, p \ 0.05) when compared with traditional laparoscopy. This result was shown to be caused by the following: (1) six to eight times longer NPT with NOTES (p \ 0.05) and (2) higher average activation levels shown in regard to biceps, extensor digitorum communis, and thenar compartment (p \ 0.05), the muscles responsible for specific joint movements to hold and operate the scope. Conclusion This study demonstrated that performing NOTES is significantly more challenging for surgeons than laparoscopy. The greater amount of muscular exertion required is linked to higher ergonomic risks. Based on the depth and strength of our results, we propose that an alternative NOTES platform be designed, one that overcomes the awkward operational mechanism of the dualworking-channel flexible endoscope.

Surgical Endoscopy, 2010

Current laparoscopic images are rich in surface detail but lack information on deeper structures.... more Current laparoscopic images are rich in surface detail but lack information on deeper structures. This report presents a novel method for highlighting these structures during laparoscopic surgery using continuous multislice computed tomography (CT). This has resulted in a more accurate augmented reality (AR) approach, termed "live AR," which merges three-dimensional (3D) anatomy from live low-dose intraoperative CT with live images from the laparoscope. A series of procedures with swine was conducted in a CT room with a fully equipped laparoscopic surgical suite. A 64-slice CT scanner was used to image the surgical field approximately once per second. The procedures began with a contrast-enhanced, diagnostic-quality CT scan (initial CT) of the liver followed by continuous intraoperative CT and laparoscopic imaging with an optically tracked laparoscope. Intraoperative anatomic changes included user-applied deformations and those from breathing. Through deformable image registration, an intermediate image processing step, the initial CT was warped to align spatially with the low-dose intraoperative CT scans. The registered initial CT then was rendered and merged with laparoscopic images to create live AR. Superior compensation for soft tissue deformations using the described method led to more accurate spatial registration between laparoscopic and rendered CT images with live AR than with conventional AR. Moreover, substitution of low-dose CT with registered initial CT helped with continuous visualization of the vasculature and offered the potential of at least an eightfold reduction in intraoperative X-ray dose. The authors proposed and developed live AR, a new surgical visualization approach that merges rich surface detail from a laparoscope with instantaneous 3D anatomy from continuous CT scanning of the surgical field. Through innovative use of deformable image registration, they also demonstrated the feasibility of continuous visualization of the vasculature and considerable X-ray dose reduction. This study provides motivation for further investigation and development of live AR.

Surgical Endoscopy, 2011

Laparoscopic incisional hernia repair (LIHR) is a common procedure requiring advanced laparoscopi... more Laparoscopic incisional hernia repair (LIHR) is a common procedure requiring advanced laparoscopic skills. This study aimed to develop a procedure-specific tool to assess the performance of LIHR and to evaluate its reliability and validity. The Global Operative Assessment of Laparoscopic Skills-Incisional Hernia (GOALS-IH) is a 7-item global rating scale developed by experts to evaluate the steps of LIHR (placement of trocars, adhesiolysis, estimation of mesh size and shape, mesh orientation and positioning, mesh fixation, knowledge and autonomy in use of instruments, overall competence), each rated on a 5-point Likert scale. During LIHR, 13 attending surgeons and fellows experienced in minimally invasive surgery (MIS) and 19 novice surgeons (postgraduate years [PGYs], 3-5) were evaluated at four teaching hospitals by the attending surgeon, a trained observer, and self-assessment using GOALS-IH, and by a previously validated 5-item general laparoscopic rating scale (GOALS). Interrater reliability was assessed by intraclass correlation (ICC), and internal consistency of rating items was assessed by Cronbach's alpha. Known-groups construct validity was assessed by using the t-test and by correlating of the number of self-reported LIHR cases with the total score. Concurrent validity was assessed by correlating the GOALS-IH score with the GOALS general rating scale. Data are presented as mean and 95% confidence interval (CI). Interrater reliability for the total GOALS-IH score was 0.79 (95% CI, 0.60-0.89) between observers and attending surgeons, 0.81 (95% CI, 0.58-0.92) between participants and attending surgeons, and 0.89 (95% CI, 0.76-0.96) between participants and observers. Internal consistency was high (Cronbach's alpha, 0.93). Experienced surgeons performed significantly better than novices as assessed by GOALS-IH (31; 95% CI, 29-33 vs. 21; 95% CI, 19-24; p < 0.01). Very good correlation was found between GOALS-IH and previous LIHR experience (r = 0.82; p < 0.01) and strong correlation between GOALS-IH and generic GOALS total scores (r = 0.90; p < 0.01). Surgical performance during clinical LIHR can be assessed reliably using GOALS-IH. Results can be used to provide formative feedback to the surgeon and to identify steps of the operation that would benefit from specific educational interventions.

Journal of Surgical Education, 2010

Journal of Gastrointestinal Surgery, 2012

Laparoscopic repair of a giant paraesophageal hiatal hernia remains a challenging procedure. Seve... more Laparoscopic repair of a giant paraesophageal hiatal hernia remains a challenging procedure. Several techniques have been developed in efforts to achieve tension-free reconstruction of the esophageal hiatus. In this report, we describe a technique whereby the falciform ligament is used as an autologous onlay flap to achieve tension-free closure of the crural defect of a giant paraesophageal hernia (GPEH). Use of the falciform ligament as a vascularized autologous onlay flap is a safe and effective procedure to obtain closure of the crural defect of a GPEH. The falciform ligament should be adequately mobilized from the anterior abdominal wall to prevent lateral tension on the flap, but care must be taken to avoid devascularization. Interrupted vertical mattress sutures are used to fix the falciform ligament to the left and right hiatal crurae.

The American surgeon, 2013

Virtual reality (VR) simulators may hold a role in the assessment of trainee abilities independen... more Virtual reality (VR) simulators may hold a role in the assessment of trainee abilities independent of their role as instructional instruments. Thus, we piloted a course in flexible endoscopy to surgical trainees who had met Accreditation Council for Graduate Medical Education endoscopy requirements to establish the relationship between metrics produced by a VR endoscopic simulator and trainee ability. After a didactic session, we provided faculty instruction to senior residents for Case 1 upper endoscopy and colonoscopy modules on the CAE EndoscopyVR. Course conclusion was defined as a trainee meeting all proficiency standards in basic endoscopic procedures on the simulator. Simulator metrics and course evaluation comprised data. Eleven and eight residents participated in the colonoscopy and upper endoscopy courses, respectively. Average time to reach proficiency standards for esophagogastroduodenoscopy was 6 and 13 minutes for colonoscopy after a median of one (range, one to two) a...