Virtual pointer for gaze guidance in laparoscopic surgery.

BACKGROUND: A challenge of laparoscopic surgery is learning how to interpret the indirect view of the operative field. Acquiring professional vision-understanding what to see and which information to attend to, is thereby an essential part of laparoscopic training and one in which trainers exert great effort to convey. We designed a virtual pointer (VP) that enables experts to point or draw free-hand sketches over an intraoperative laparoscopic video for a novice to see. This study aimed to investigate the efficacy of the virtual pointer in guiding novices' gaze patterns. METHODS: We conducted a counter-balanced, within-subject trial to compare the novices' gaze behaviors in laparoscopic training with the virtual pointer compared to a standard training condition, i.e., verbal instruction with un-mediated gestures. In the study, seven trainees performed four simulated laparoscopic tasks guided by an experienced surgeon as the trainer. A Tobii Pro X3-120 eye-tracker was used to capture the trainees' eye movements. The measures include fixation rate, i.e., the frequency of trainees' fixations, saccade amplitude, and fixation concentration, i.e., the closeness of trainees' fixations. RESULTS: No significant difference in fixation rate or saccade amplitude was found between the virtual pointer condition and the standard condition. In the virtual pointer condition, trainees' fixations were more concentrated (p = 0.039) and longer fixations were more clustered, compared to the Standard condition (p = 0.008). CONCLUSIONS: The virtual pointer effectively improved surgical trainees' in-the-moment gaze focus during the laparoscopic training by reducing their gaze dispersion and concentrating their attention on the anatomical target. These results suggest that technologies which support gaze training should be expert-driven and intraoperative to efficiently modify novices' gaze behaviors.

Laparoscopic cholecystectomy poses physical injury risk to surgeons: analysis of hand technique and standing position.

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. between-standing 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: one-handed/side-standing, one-handed/between-standing, two-handed/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 side-standing 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 one-handed (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.

Effects of a Virtual Pointer on Trainees' Cognitive Load and Communication Efficiency in Surgical Training.

We investigated the cognitive load effect of a trainer providing surgical instruction by pointing/drawing over laparoscopic video to a trainee. Results showed that while cognitive load is higher overall with the use of the instructional system, there is a decrease by the second experience of being instructed by the Virtual Pointer. Further analysis showed that trainees were more likely to perform the surgical task and watch/listen to the trainer's instruction at the same time when the instructional system was used. This is thought to be an indication of more efficient communication when using the instructional system. Thus, although there is a small cognitive overload with the instructional system initially, the more efficient communication allows trainees to better integrate the knowledge and instructions being conveyed into the actions they must perform - indicating a better learning environment.

A virtual pointer to support the adoption of professional vision in laparoscopic training.

PURPOSE: To assess a virtual pointer in supporting surgical trainees' development of professional vision in laparoscopic surgery. METHODS: We developed a virtual pointing and telestration system utilizing the Microsoft Kinect movement sensor as an overlay for any imagine system. Training with the application was compared to a standard condition, i.e., verbal instruction with un-mediated gestures, in a laparoscopic training environment. Seven trainees performed four simulated laparoscopic tasks guided by an experienced surgeon as the trainer. Trainee performance was subjectively assessed by the trainee and trainer, and objectively measured by number of errors, time to task completion, and economy of movement. RESULTS: No significant differences in errors and time to task completion were obtained between virtual pointer and standard conditions. Economy of movement in the non-dominant hand was significantly improved when using virtual pointer ([Formula: see text]). The trainers perceived a significant improvement in trainee performance in virtual pointer condition ([Formula: see text]), while the trainees perceived no difference. The trainers' perception of economy of movement was similar between the two conditions in the initial three runs and became significantly improved in virtual pointer condition in the fourth run ([Formula: see text]). CONCLUSIONS: Results show that the virtual pointer system improves the trainer's perception of trainee's performance and this is reflected in the objective performance measures in the third and fourth training runs. The benefit of a virtual pointing and telestration system may be perceived by the trainers early on in training, but this is not evident in objective trainee performance until further mastery has been attained. In addition, the performance improvement of economy of motion specifically shows that the virtual pointer improves the adoption of professional vision- improved ability to see and use laparoscopic video results in more direct instrument movement.

Postural instability does not necessarily correlate to poor performance: case in point.

BACKGROUND: It is very important for surgeons who perform minimally invasive surgery (MIS) to maintain proper postural stability, which kinematic research can determine. Previous studies in surgical ergonomics have shown that postural stability is correlated to instrument type, task difficulty, and skill level. What should also be considered is that surgeons may strategically change stance or joint movement to achieve better surgical outcomes while potentially subjecting themselves to greater risk. Background information about subjects, e.g., joint impairment, should be considered an important surgical ergonomic element. Such information can lead to more realistic and accurate conclusions about postural stability and joint kinematics. METHODS: A highly experienced and skilled right-handed surgeon developing carpal tunnel syndrome in both wrists was recruited into a small (6 subjects) performance study of pegboard transfer and circle-cutting tasks from the Fundamentals of Laparoscopic Surgery (FLS) skill set. Joint kinematics and postural data were collected using two associated force plates and a motion capture system of 12 digital, high-resolution, high-speed, infrared cameras. RESULTS: Each task was completed in less than 90 s. In pegboard transfer, the subject increased shoulder abduction angle to align his hand and forearm and minimize wrist flexion. When circle-cutting required excessive wrist flexion, the subject maintained his lower body position and stance while twisting his torso, a strategy that appeared to stabilize tangential direction related to cutting while maintaining a fixed orientation of forearm, wrist, and hand. In another circle-cutting trial, the subject changed his stance primarily by shifting foot position as necessary to obtain better scissor approach angles. These compensatory, strategic movements caused an increase in overall postural sway but did not represent postural instability. CONCLUSION: This case study indicated that poor joint kinematics or postural stability does not necessarily correlate to poor performance. Instead, they may indicate positive compensatory or strategic movements.

Wireless live streaming video of laparoscopic surgery: a bandwidth analysis for handheld computers.

Over the last six years, streaming media has emerged as a powerful tool for delivering multimedia content over networks. Concurrently, wireless technology has evolved, freeing users from desktop boundaries and wired infrastructures. At the University of Kentucky Medical Center, we have integrated these technologies to develop a system that can wirelessly transmit live surgery from the operating room to a handheld computer. This study establishes the feasibility of using our system to view surgeries and describes the effect of bandwidth on image quality. A live laparoscopic ventral hernia repair was transmitted to a single handheld computer using five encoding speeds at a constant frame rate, and the quality of the resulting streaming images was evaluated. No video images were rendered when video data were encoded at 28.8 kilobytes per second (Kbps), the slowest encoding bitrate studied. The highest quality images were rendered at encoding speeds greater than or equal to 150 Kbps. Of note, a 15 second transmission delay was experienced using all four encoding schemes that rendered video images. We believe that the wireless transmission of streaming video to handheld computers has tremendous potential to enhance surgical education. For medical students and residents, the ability to view live surgeries, lectures, courses and seminars on handheld computers means a larger number of learning opportunities. In addition, we envision that wireless enabled devices may be used to telemonitor surgical procedures. However, bandwidth availability and streaming delay are major issues that must be addressed before wireless telementoring becomes a reality.

Classification of hiatal hernias using dynamic three-dimensional reconstruction.

Hiatal hernias and paraesophageal hernias are common clinical entities and have a well-known classification system. Multiple modalities have been used to illustrate these hernias, most relying on artists' renderings or two-dimensional radiographic studies. However, surgeons would benefit from a comprehensive graphic representation of hiatal hernias based on current imaging technologies. We have applied polygonal mesh surface modeling techniques to render dynamic three-dimensional computed tomography-based models of the four recognized types of hiatal hernias. The resulting images allow nearly real-time navigation in an intuitive and clinically relevant fashion. This model should clarify and eventually advance the existing classification by applying modern and sophisticated image processing to established concepts.