Quantifying mental workloads of surgeons performing natural orifice transluminal endoscopic surgery (NOTES) procedures.

BACKGROUND: During natural orifice transluminal endoscopic surgery (NOTES), surgeons often have difficulties orienting the surgical view and manipulating instruments accurately, which increases their level of mental and physical fatigue. This study quantified mental workload by measuring the spared mental resources of surgeons performing NOTES training tasks. METHODS: Assessment of mental workload was conducted in both a benchtop and a hybrid animal model. Using the benchtop model, surgeons were required to pass a ring as many times as possible in 6 min. Using the hybrid model, surgeons were required to dissect the gallbladder. While performing those primary tasks, the surgeon was required to identify true visual signals among many false signals displayed on an adjacent monitor. They were asked to repeat the trials using laparoscopy. The surgeons' performance on the primary and secondary tasks using the NOTES and laparoscopic approaches were recorded and compared. RESULTS: The nine surgeons who completed the trials in the benchtop model successfully transferred 13 ± 4 rings between targets using laparoscopy compared with a mean of 1.2 ± 1.0 rings transferred using NOTES (P < 0.001). The surgeons detected visual signals at a 74% rate using laparoscopy, which was significantly higher than the 54% detection rate with the NOTES procedure (P = 0.005). Using the hybrid model, 10 surgeons achieved a 55% accuracy rate performing the laparoscopic task. This was found to be significantly higher (P = 0.006) than when the task was performed using the NOTES platform (39%). CONCLUSION: The results showed that performance of a task using the NOTES platform increases surgeons' mental workload. Because difficulty performing NOTES is associated with flexible endoscopy, the authors expect that new operating systems providing stable platforms will help to decrease the mental workload of surgeons and enhance eye-hand coordination in performing NOTES.

A novel technique for natural orifice endoscopic full-thickness colon wall resection: an experimental pilot study.

BACKGROUND: Natural orifice endoscopic full-thickness colon resection attempts to overcome the need for invasive surgery in selected colorectal indications. Because basic technical requirements have not been met so far, the aim of this study was to develop a novel technique for endolumenal colon-wedge resection addressing current shortcomings. STUDY DESIGN: Endoscopic full-thickness colon resection was attempted in a human cadaver model (n = 2), explanted porcine colon stumps (n = 10), and 3 acute pig models. A hypothesized colon lesion was created and retracted into an endoscopic clip closure system (ECCS). Initially used endoscopic graspers (n = 2) were replaced by a T-tag suture approach for retraction (n = 13). T-type anchors were deployed circumferentially to the lesion, which simultaneously marked resection margins. The clip was then applied for pre-resection tissue closure. The inverted tissue was excised by snare resection and was removed together with the sutures. Air leak-pressure of tissue closure was tested. RESULTS: Endoscopic full-thickness colon resection was achieved in 14 of 15 attempts. The mean diameter (±SD) of resected animal specimen, including the predetermined margins, was 26 ± 4 mm. Using the T-tag sutures for retraction, the defined lesion was neither touched by an endoscopic grasper nor compromised by puncturing the center. Leak pressure tests revealed a significantly higher air pressure resistance of the pre-resection ECCS closure (61 ± 5 mmHg) compared with the hand-sewn control (26 ± 7 mmHg). CONCLUSIONS: A novel endoscopic technique for full-thickness colon wall resection using tissue anchors for traction and an ECCS for pre-resection tissue closure appears to address several fundamental surgical principles. However, further studies are necessary before initial clinical application.

A natural orifice transrectal approach for oncologic resection of the rectosigmoid: an experimental study and comparison with conventional laparoscopy.

BACKGROUND: A transrectal (TR) approach for natural orifice translumenal endoscopic surgery (NOTES) makes sense for colorectal surgery because the colotomy can be incorporated into subsequent anastomosis. Because cancer is a primary indication for left-sided colon resection, oncologic standards will have to be met by a NOTES procedure. This study aimed to assess whether pure TR rectosigmoidectomy can be performed with strict adherence to oncologic principles compared with a conventional laparoscopically assisted approach (LAP). METHODS: Human male cadavers were allocated to either TR (n = 4) or LAP (n = 2). A simulated sigmoid lesion was created at 25 cm. Transrectal retrograde mobilization of the rectosigmoid was performed using conventional transanal endoscopic microsurgery (TEM) instrumentation. After ligation of the superior hemorrhoidal artery and further mobilization, the specimen was delivered transanally and divided extracorporeally. Using a circular stapler, NOTES colorectal anastomosis was performed. Lymph node yield, adequate resection margins, and operative time were compared with LAP. RESULTS: Transrectal retrograde rectosigmoid dissection was achieved in all attempts (4/4) and showed numbers of lymph nodes (median, 5; range, 3-6) similar to the LAP group (median, 4.5; range, 2-7). One pure TR approach failed to resect the lesion. Three TR procedures required additional mobilization via an abdominal approach to provide adequate margins. The mean length of TR specimens was 16 ± 4 cm compared with 31 ± 9 cm achieved by LAP (p < 0.01). The TR operative time was significantly longer (247 ± 15 vs 110 ± 14 min). CONCLUSION: Lymph node yield during TR rectosigmoidectomy was similar to that achieved by the LAP approach. However, conventional TEM instrumentation alone did not permit adequate colon mobilization. This indicates a need for flexible instrumentation or other technical solutions to perform true NOTES colectomies.

Flexible endoscopic Zenkers diverticulotomy with a novel bipolar forceps: a pilot study and comparison with needleknife dissection.

BACKGROUND: Zenker's diverticulum (ZD) is the most common diverticulum of the upper gastrointestinal tract. Various flexible endoscopic techniques have been used for division of the septum. However, the learning curve associated with these techniques might be difficult to overcome given the overall rarity of this condition. This can lead either to complications or to potential recurrence of symptoms. The authors hypothesized that a flexible bipolar hemostasis forceps developed for natural orifice translumenal surgery (NOTES) procedures would facilitate precise endoscopic diverticulotomy and simultaneously enable sealing of divided tissue edges. METHODS: Because the pharyngeal diverticulum (PD) in the pig is comparable with a human ZD, this nonsurvival model was used to perform endoscopic diverticulotomy using two energy technologies. The PD septum was dissected with either a flexible and a rotating bipolar forceps (n = 5) or with standard needleknife cautery (NK; n = 3). The feasibility and safety of the two technologies were compared. RESULTS: In contrast to NK myotomy, the bipolar forceps could easily be readjusted before any tissue dissection in all (5/5) interventions, and energy was applied only on the tissue to be divided. Tissue bonding at the edges of the septum was observed in all cases. The monopolar energy in NK dissection made precise and centered division of the septum difficult to achieve and did not bond the edges of the septum. One perforation occurred with NK (1/3). CONCLUSIONS: The flexible bipolar forceps used for Zenker's diverticulotomy is appealing due to its ease of application and potential to coaptate mucomuscular tissue edges. Although further evaluation with a survival model is necessary, it also seems to be a safer approach than NK. This novel tool could facilitate performance of surgical endoscopists and may make flexible endoscopy the preferred method for Zenker's ablation.

A triangulating operating platform enhances bimanual performance and reduces surgical workload in single-incision laparoscopy.

BACKGROUND: Single-site laparoscopy (SSL) attempts to further reduce the surgical impact of minimally invasive surgery. However, crossed instruments and the proximity of the endoscope to the operating instruments placed through one single site leads to inevitable instrument or trocar collision. We hypothesized that a novel, single-port, triangulating surgical platform (SPSP) might enhance performance by improving bimanual coordination and decreasing the surgeon's mental workload. STUDY DESIGN: Fourteen participants, proficient in basic laparoscopic skills, were tested on their ability to perform a validated intracorporeal suturing task by either an SSL approach with crossed articulated instruments or a novel SPSP, providing true-right and true-left manipulation. Standard laparoscopic (SL) access served as control. Sutures were evaluated using validated scoring methods and the National Aeronautics and Space Administration Task Load Index was used to rate mental workload. RESULTS: All participants proficiently performed intracorporeal knots by SL (mean score 99.0; 95% CI 97.0 to 100.9). Performance decreased significantly (more than 50%, p < 0.001) with the SSL approach using 1 rigid and 1 articulating instrument in a cross-wise manner (mean score 39.2; 95% CI 28.3 to 50.1). The use of the SPSP significantly enhanced bimanual coordination (mean score 67.6; 95% CI 61.3 to 73.9; p < 0.001). Participants recorded lower mental workload when using true-right and true-left manipulation. CONCLUSIONS: This study objectively assessed SSL performance and current attempts for instrumentation improvement in single-site access. While SSL significantly impairs basic laparoscopic skills, surgical platforms providing true-left and true-right maneuvering of instruments appear to be more intuitive and address some of the current challenges of SSL that may otherwise limit its widespread acceptance.

Transcervical heller myotomy using flexible endoscopy.

INTRODUCTION: Esophageal achalasia is most commonly treated by laparoscopic myotomy. Transesophageal approaches using flexible endoscopy have recently been described. We hypothesized that using techniques and flexible instruments from our NOTES experience through a small cervical incision would be a safer and less traumatic route for esophageal myotomy. The purpose of this study was to evaluate the feasibility, safety, and success rate of using flexible endoscopes to perform anterior or posterior Heller myotomy via a transcervical approach. METHODS: This animal (porcine) and human cadaver study was conducted at the Legacy Research and Technology Center. Mediastinal operations on ten live, anesthetized pigs and two human cadavers were performed using standard flexible endoscopes through a small incision at the supra-sternal notch. The esophagus was dissected to the phreno-esophageal junction using balloon dilatation in the peri-esophageal space followed by either anterior or posterior distal esophageal myotomy. Success rate was recorded of esophageal dissection to the diaphragm and proximal stomach, anterior and posterior myotomy, perforation, and complication rates. RESULTS: Dissection of the esophagus to the diaphragm and performing esophageal myotomy was achieved in 100% of attempts. Posterior Heller myotomy was always extendable onto the gastric wall, while anterior gastric extension of the myotomy was found to be more difficult (4/4 and 2/8, respectively; P = 0.061). CONCLUSION: Heller myotomy through a small cervical incision using flexible endoscopes is feasible. A complete Heller myotomy was performed with a higher success rate posteriorly possibly due to less anatomic interference.

Video: natural orifice translumenal endoscopic surgery (NOTES): creation of a gastric valve for safe and effective transgastric surgery in humans.

INTRODUCTION: NOTES has become a clinical reality. There remain, however, many challenges that need to be addressed in order to refine the technique. One of the most feared potential complications of transgastric surgery is a leak from the port of entry into the peritoneum. When withdrawing the endoscope into the gastric lumen it is difficult to make a secure closure due to the loss of pneumogastrium. We present a novel and safe technique for creating a gastrotomy developed in our animal laboratory and applied in all of our human NOTES cholecystectomies. METHODS: Using an aggressive grasping and needle-delivery device, full-thickness bites create an imbricated ridge of tissue that acts as a valve, allowing visualization while maintaining pneumogastrium when the endoscope is withdrawn from the peritoneum into the lumen. At closure, full-thickness serosa-to-serosa approximation is easily achieved due to excellent visualization. RESULTS: With this technique we have been able to accomplish consistent results in ten pig models. In our series of five patients who have undergone NOTES transgastric cholecystectomy, there have been no leaks to date using the same technique. Video footage presents this technique performed on humans. CONCLUSIONS: Creation of a gastric valve during transgastric surgery has proved to be a safe approach. This technique allows maintenance of insufflation and visualization during the procedure and provides a feasible and safe means of closure at the end of the procedure.

Endoscopic closure of gastrogastric fistulas by using a tissue apposition system (with videos).

BACKGROUND: Gastrogastric fistulas (GGFs) are seen in 1.5% to 12.5% of patients after Roux-en-Y gastric bypass (RYGB) bariatric surgery, often leading to failure to lose adequate weight. OBJECTIVE: The aim of this study was to assess the feasibility, safety, and percentage of successful primary endoluminal closures of GGFs by using a recently developed tissue apposition system in combination with local mucosectomy. DESIGN: A feasibility and outcome study following institutional review board protocol. SETTING: Tertiary referral teaching hospital, Legacy Health System, Portland, Oregon. INTERVENTIONS: A combination of mucosectomy and nonresorbable tissue apposition is used to achieve a permanent closure of the GGF. PATIENTS: Four patients with 5 GGFs after RYGB; the mean fistula diameter of was 18.6 mm (range 10-30 mm). RESULTS: Primary closure rate (1 endoscopic session) of 5 GGFs was 100%. The mean procedure time was 88.5 minutes. One to 4 pairs of tissue anchors were used to close the fistulas. The mean time for performing mucosectomy was 21.6 minutes (range 8-42 minutes) and 39.6 minutes (range 12-58 minutes) for fistula closure. Estimated blood loss was on average 2 mL (range 0-5 mL). No complications were recorded. Early success (3 months), as evidenced by early satiety and weight loss, was noted for 3 of 4 patients. After 3 months, only the smallest fistula (10 mm) was still completely closed, and after 6 months, it also showed a pinhole opening. CONCLUSION: It was feasible to close all fistulas endoscopically without complications. Permanent closure of GGFs could not be achieved.

Measuring mental workload during the performance of advanced laparoscopic tasks.

INTRODUCTION: Mental workload is a finite resource and is increased while learning new tasks and performing complex tasks. Measurement of a surgeon's mental workload may therefore be an indication of expertise. We hypothesized that surgeons who were expert at laparoscopic suturing would have more spare mental resources to perform a secondary task, compared with surgeons who had just started to learn suturing. METHODS: Standardized suturing tasks were performed on a bench-top model. Twelve junior residents (novices) and nine fellows and attending surgeons (experts) were instructed to perform as many sutures as possible in 6 min. An adjacent monitor was placed 15 degrees off axis to the first and randomly displayed 30 true visual signals among 90 false ones. Participants were required to identify the true signals while continuing to suture. Laparoscopic sutures were evaluated using the Fundamentals of Laparoscopic Surgery (FLS) scoring system. The secondary (visual detection) task was evaluated by calculating the rate of missed true signals or detection of false signals. RESULTS: Experts completed significantly more secure sutures (6 +/- 2) than novices (3 +/- 1; p = 0.001). The suture performance score was 50 +/- 20 for experts, significantly higher than for novices (29 +/- 10; p = 0.005). The rate for detecting visual signals was higher for experts (98%) compared with for novices (93%; p = 0.041). CONCLUSION: Practice develops automaticity, which reduces the mental workload and allows surgeons to have sufficient spare mental resources to attend to a secondary task. Visual detection provides a simple and reliable way to assess mental workload and situation awareness abilities of surgeons during skills training, and may be an indirect measure of expertise.

Bimanual coordination in natural orifice transluminal endoscopic surgery: comparing the conventional dual-channel endoscope, the R-Scope, and a novel direct-drive system.

BACKGROUND: The devices used for natural orifice transluminal endoscopic surgery procedures are endoscopes or inspired by endoscopic design, which makes it difficult to accomplish bimanual coordination. OBJECTIVE: We evaluated 3 operating systems in simulated natural orifice transluminal endoscopic surgery procedures requiring complex bimanual coordination. DESIGN: Operators were required to perform an identical bimanual task by using 3 operating systems: a dual-channel endoscope (DCE); the R-Scope, which has 2 elevators for independent movement of endoscopic instruments; and the Direct Drive Endoscopic System (DDES), which allows separation of instruments and vision, emulating more of a laparoscopic surgery paradigm. SETTING: A bench-top simulation was used. Twelve teams were recruited for DCE and R-Scope testing. Twelve individuals participated in the DDES setup. The task included 3 steps: picking up a ring, passing it between endoscopic instruments, and placing it on a designated location. MAIN OUTCOME MEASUREMENTS: Task performance was evaluated by movement speed and accuracy. RESULTS: Task performance was significantly faster when using the DDES system (29 +/- 28 seconds) compared with the other operating systems (DCE: 140 +/- 55 seconds, R-Scope: 160 +/- 71 seconds; P < .001). The difference between the DCE and the R-Scope was not significant (P = .370). CONCLUSION: Designs that separate vision and motion have more degrees of freedom at the tip of the instruments, and an ergonomic user interface provides benefits for bimanual performance compared with more traditional endoscopic designs. With the DDES, a single operator can perform complex endoscopic tasks faster than 2 operators with a DCE or R-Scope.

The trade-off between flexibility and maneuverability: task performance with articulating laparoscopic instruments.

BACKGROUND: Laparoscopic instruments are rigid and thus cannot provide the degrees of freedom (DOF) needed by a surgeon in certain situations. A new generation of laparoscopic instruments with the ability to articulate their end effectors is available. Although these instruments offer the flexibility needed to perform complex tasks in a constricted surgical site, their control may be hampered by their increased complexity. METHODS: This study compared the task performance between articulating and conventional laparoscopic instruments. Surgeons with extensive laparoscopic experience (8 experts) and staff with no surgical experience (8 novices) were recruited for the test. Both groups were required to perform three standardized tasks (peg transfer, left-to-right suturing, and up-and-down suturing) in a bench top model using conventional and articulating instruments. Performance was scored using a standardized 100-point scale based on movement speed and accuracy. After the initial trials with conventional and articulating instruments, each participant was given a short orientation on how to use the articulating instrument advantageously. The participant then was retested with the articulating instrument. RESULTS: As expected, the expert group scored significantly better than the novice group (p < 0.001). The combined data from both groups showed better performance with the conventional instruments than with the articulating instruments (p = 0.074). The experts maintained their proficient laparoscopic performance using conventional instruments in their first attempts with the articulating instruments (91 vs. 84), whereas the novices had greater difficulty with the articulating instruments than with the conventional instruments (46 vs. 59). After a short orientation, however, the novices outscored the expert group in terms of net improvement in performance with the articulating instrument (27 vs. 1% improvement). CONCLUSION: Experienced surgeons are readily able to transfer their skills from conventional to articulating laparoscopic instruments. To speed the learning process, the use of articulating instruments can be started at an early stage of surgical training.

Surgical time independently affected by surgical team size.

BACKGROUND: Team size and composition provide essential data for the study of operating room (OR) efficiency. METHODS: Laparoscopic procedures between July 2005 and July 2007 were reviewed retrospectively to record the number of OR personnel and the procedure time (PT). RESULTS: Of 399 procedures reviewed, 360 cases with complete data were analyzed. The average PT was 148 minutes. A mean of 8 different team members (range, 4-15) were involved. Surgeons and anesthesiologists stayed constant whereas the OR nurses were replaced more than once per procedure (mean, 4 nurses/procedure; range, 2-11). Multiple regression analysis revealed that both complexity of surgery and team size affected the PT significantly. When procedure complexity and patient condition were held constant, we found that adding 1 individual to a team predicted a 15.4-minutes increase in PT. CONCLUSIONS: The surgical team is a dynamic system with a large amount of member turnover. Efforts to improve OR efficiency should focus on decreasing surgical team size, limiting staff turnover, and enhancing communication between team members.

A quantitative study of disruption in the operating room during laparoscopic antireflux surgery.

BACKGROUND: Many activities performed by team members in the operating room (OR) are not directly related to the achievement of the surgical goal. METHODS: A video-aided observational field study was conducted in the OR to examine disruptive events during laparoscopic antireflux surgery. Disruptive events were categorized into one of six groups: instrument change, surgeon position change, nurse duty shift, conversation, phone/pager answering, and extraneous interruption. The frequency and duration of each type of disruptive event were recorded. Events were further categorized based on whether or not they delayed the workflow. RESULTS: The average procedure time of 12 observed cases was 123 min. On average, a total of 114 disruptive events were recorded per hour. Intraoperative conversations were recorded with the highest frequency (71 episodes/h) and longest duration (16 min/h); however, most conversations did not delay surgical workflow. The events that generated most surgical delays were instrument change (3.4 min/h), which included times for placing essential instruments into the surgical site and time spent waiting for an unavailable instrument. On average, disruptive events performed in the OR caused 4.1 min of delay for each case per hour, corresponding to 6.5% of the procedure time. CONCLUSIONS: This study demonstrated the feasibility of using video-aided observational studies for developing objective assessment of team quality in the OR. Categorizing disruptive events and examining their negative impact on the OR time will help to develop methods to eliminate inefficiency inside the OR.

Verbal communication improves laparoscopic team performance.

The impact of verbal communication on laparoscopic team performance was examined. A total of 24 dyad teams, comprised of residents, medical students, and office staff, underwent 2 team tasks using a previously validated bench model. Twelve teams (feedback groups) received instant verbal instruction and feedback on their performance from an instructor which was compared with 12 teams (control groups) with minimal or no verbal feedback. Their performances were both video and audio taped for analysis. Surgical backgrounds were similar between feedback and control groups. Teams with more verbal feedback achieved significantly better task performance (P = .002) compared with the control group with less feedback. Impact of verbal feedback was more pronounced for tasks requiring team cooperation (aiming and navigation) than tasks depending on individual skills (knotting). Verbal communication, especially the instructions and feedback from an experienced instructor, improved team efficiency and performance.