Perceptual impairment and psychomotor control in virtual laparoscopic surgery

Background: It is recognised that one of the major difficulties in performing laparoscopic surgery is the translation of two-dimensional video image information to a three-dimensional working area. However, research has tended to ignore the gaze and eye-hand coordination strategies employed by laparoscopic surgeons as they attempt to overcome these perceptual constraints. This study sought to examine if measures related to tool movements, gaze strategy, and eye-hand coordination (the quiet eye) differentiate between experienced and novice operators performing a two-handed manoeuvres task on a virtual reality laparoscopic surgical simulator (LAP Mentor™). Methods: Twenty-five right-handed surgeons were categorised as being either experienced (having led more than 60 laparoscopic procedures) or novice (having performed fewer than 10 procedures) operators. The 10 experienced and 15 novice surgeons completed the "two-hand manoeuvres" task from the LAP Mentor basic skills learning environment while wearing a gaze registration system. Performance, movement, gaze, and eye-hand coordination parameters were recorded and compared between groups. Results: The experienced surgeons completed the task significantly more quickly than the novices, used significantly fewer movements, and displayed shorter tool paths. Gaze analyses revealed that experienced surgeons spent significantly more time fixating the target locations than novices, who split their time between focusing on the targets and tracking the tools. A more detailed analysis of a difficult subcomponent of the task revealed that experienced operators used a significantly longer aiming fixation (the quiet eye period) to guide precision grasping movements and hence needed fewer grasp attempts. Conclusion: The findings of the study provide further support for the utility of examining strategic gaze behaviour and eye-hand coordination measures to help further our understanding of how experienced surgeons attempt to overcome the perceptual difficulties inherent in the laparoscopic environment. © 2011 The Author(s).published_or_final_versionSpringer Open Choice, 21 Feb 201

The value of haptic feedback in conventional and robot-assisted minimal invasive surgery and virtual reality training: a current review

BACKGROUND: Virtual reality (VR) as surgical training tool has become a state-of-the-art technique in training and teaching skills for minimally invasive surgery (MIS). Although intuitively appealing, the true benefits of haptic (VR training) platforms are unknown. Many questions about haptic feedback in the different areas of surgical skills (training) need to be answered before adding costly haptic feedback in VR simulation for MIS training. This study was designed to review the current status and value of haptic feedback in conventional and robot-assisted MIS and training by using virtual reality simulation. METHODS: A systematic review of the literature was undertaken using PubMed and MEDLINE. The following search terms were used: Haptic feedback OR Haptics OR Force feedback AND/OR Minimal Invasive Surgery AND/OR Minimal Access Surgery AND/OR Robotics AND/OR Robotic Surgery AND/OR Endoscopic Surgery AND/OR Virtual Reality AND/OR Simulation OR Surgical Training/Education. RESULTS: The results were assessed according to level of evidence as reflected by the Oxford Centre of Evidence-based Medicine Levels of Evidence. CONCLUSIONS: In the current literature, no firm consensus exists on the importance of haptic feedback in performing minimally invasive surgery. Although the majority of the results show positive assessment of the benefits of force feedback, results are ambivalent and not unanimous on the subject. Benefits are least disputed when related to surgery using robotics, because there is no haptic feedback in currently used robotics. The addition of haptics is believed to reduce surgical errors resulting from a lack of it, especially in knot tying. Little research has been performed in the area of robot-assisted endoscopic surgical training, but results seem promising. Concerning VR training, results indicate that haptic feedback is important during the early phase of psychomotor skill acquisitio

The risk factors and predictive factors for anastomotic leakage after resection for colorectal cancer: reappraisal of the literature

Anastomotic leakage is a serious complication that can occur after colorectal surgery. Several risk factors for anastomotic leakage have been reported based on the findings of prospective and retrospective studies, including patient characteristics, the use of neoadjuvant therapy, the tumor location, intraoperative events, etc. However, as these risk factors affect each other, the statistical results have differed in each study. In addition, differences in surgical methods, including laparoscopy versus laparotomy or stapling anastomosis versus handsewn anastomosis, may influence the incidence of anastomotic leakage. This mini-review summarizes the results of reported papers to clarify the current evidence of risk factors for anastomotic leakage

The HIV-1 transmission bottleneck

It is well established that most new systemic infections of HIV-1 can be traced back to one or a limited number of founder viruses. Usually, these founders are more closely related to minor HIV-1 populations in the blood of the presumed donor than to more abundant lineages. This has led to the widely accepted idea that transmission selects for viral characteristics that facilitate crossing the mucosal barrier of the recipient’s genital tract, although the specific selective forces or advantages are not completely defined. However, there are other steps along the way to becoming a founder virus at which selection may occur. These steps include the transition from the donor’s general circulation to the genital tract compartment, survival within the transmission fluid, and establishment of a nascent stable local infection in the recipient’s genital tract. Finally, there is the possibility that important narrowing events may also occur during establishment of systemic infection. This is suggested by the surprising observation that the number of founder viruses detected after transmission in intravenous drug users is also limited. Although some of these steps may be heavily selective, others may result mostly in a stochastic narrowing of the available founder pool. Collectively, they shape the initial infection in each recipient

Three-dimensional versus two-dimensional imaging during laparoscopic cholecystectomy: a systematic review and meta-analysis of randomised controlled trials.

OBJECTIVES To evaluate the comparative outcomes of three-dimensional (3D) versus two-dimensional (2D) imaging during laparoscopic cholecystectomy. METHODS We conducted a systematic search of electronic information sources and bibliographic reference lists and applied a combination of free text and controlled vocabulary search adapted to thesaurus headings, search operators and limits. Procedure time, Calot's triangle dissection time, gallbladder removal time, gallbladder perforation, intraoperative bleeding, postoperative complications, conversion to open and intraoperative errors were the evaluated outcome parameters. RESULTS We identified 6 randomised controlled trials (RCT) reporting a total of 577 patients who underwent laparoscopic cholecystectomy using 3D (n = 282) or 2D (n = 295) imaging. The 3D imaging was associated with significantly shorter procedure time (MD - 4.23, 95% CI - 8.14 to - 0.32, p = 0.03), Calot's triangle dissection time (MD - 4.19, 95% CI - 6.52 to - 1.86, p = 0.0004) and significantly lower risk of gallbladder perforation (RR 0.50, 95% CI 0.28-0.88, p = 0.02) compared to the 2D approach. No significant difference was found in gallbladder removal time (MD - 0.79, 95% CI - 2.24 to 0.66, p = 0.28), intraoperative bleeding (RR 1.14, 95% CI 0.68-1.90, p = 0.61), postoperative complications (RD - 0.01, 95% CI - 0.06 to 0.05, p = 0.85), conversion to open (RD 0.00, 95% CI - 0.02 to 0.03, p = 0.70) or intraoperative errors (RR 0.96, 95% CI 0.79-1.17, p = 0.70) between the two groups. CONCLUSIONS Although our findings suggest that the use of 3D imaging during laparoscopic cholecystectomy may be associated with significantly shorter procedure time, Calot's triangle dissection time and gallbladder injury compared to the 2D imaging, the differences seem to be clinically insignificant. Moreover, both approaches carry s similar risk of postoperative morbidities. The impact of the surgeon's level of experience and difficulty of the procedure on the outcomes of each imaging modality remains unknown