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Background and Aims: Colonic endoscopic submucosal dissection (ESD) is time-consuming and bears a high risk of perforation. The aim of the present study was to compare the safety and efficacy between novel articulating devices and conventional ESD in live porcine colon models., Methods: Thirty ESDs in ten pigs were carried out at three different locations (15, 25, and 35 cm from the anus) by the conventional method (n = 15) and by the new method (n = 15). Procedure times, adverse events (perforation, bleeding), and damage to the muscular layer were recorded, and the ESD time per unit area of the specimens was calculated., Results: The perforation rate using the conventional method was 6.7% (1/15), whereas that using the new method was 0.0%. The number of sites of muscular damage was significantly lower in the new than conventional method (6 vs. 37, respectively; P = 0.024). The mean procedure time was significantly shorter in the new than conventional method (4.6 ± 2.0 vs. 7.0 ± 4.1 min/cm 2 , respectively; P = 0.042)., Conclusions: Use of the new ESD method allows for reduced adverse events and a shortened resection time.

Background: Difficulties in endoscopic operations and therapeutic procedures seem to occur due to the complexity of operating the endoscope dial as well as difficulty in performing synchronized movements with both hands. We developed a prototype robotic-assisted flexible endoscope that can be controlled with a single hand in order to simplify the operation of the endoscope. The aim of this study was to confirm the operability of the robotic-assisted flexible endoscope (RAFE) by performing endoscopic submucosal dissection (ESD)., Methods: Study 1: ESD was performed manually or with RAFE by an expert endoscopist in ex vivo porcine stomachs; six operations manually and six were performed with RAFE. The procedure time per unit circumferential length/area was calculated, and the results were statistically analyzed. Study 2: We evaluated how smoothly a non-endoscopist can move a RAFE compared to a manual endoscope by assessing the designated movement of the endoscope., Results: Study 1: En bloc resection was achieved by ESD using the RAFE. The procedure time was gradually shortened with increasing experience, and the procedure time of ESD performed with the RAFE was not significantly different from that of ESD performed with a manual endoscope. Study 2: The time for the designated movement of the endoscope was significantly shorter with a RAFE than that with a manual endoscope as for a non-endoscopist., Conclusions: The RAFE that we developed enabled an expert endoscopist to perform the ESD procedure without any problems and allowed a non-endoscopist to control the endoscope more easily and quickly than a manual endoscope. The RAFE is expected to undergo further development.

Purpose: We developed and validated a specific laparoscopic fundoplication simulator for use with the objective endoscopic surgical skills evaluation system. The aim of this study was to verify the quality of skills of surgeons., Materials and Methods: We developed a 1-year-old infant body model based on computed tomography data and reproduced pneumoperitoneum model based on the clinical situation. The examinees were divided into three groups: fifteen pediatric surgery experts (PSE), twenty-four pediatric surgery trainees (PSN), and ten general surgeons (GS). They each had to perform three sutures ligatures for construction of Nissen wrap. Evaluate points are time for task, the symmetry of the placement of the sutures, and the uniformity of the interval of suture ligatures in making wrap. And the total path length and velocity of forceps were measured to assess bi-hand coordination., Results: PSE were significantly superior to PSN regarding total time spent (p < 0.01) and total path length (p < 0.01). GS used both forceps faster than the other groups, and PSN used the right forceps faster than the left forceps (p < 0.05). PSE were shorter with regard to the total path length than GS (p < 0.01). PSE showed most excellent results in the symmetry of the wrap among three groups., Conclusion: Our new model was used useful to validate the characteristics between GS and pediatric surgeon. Both PSE and GS have excellent bi-hand coordination and can manipulate both forceps equally and had superior skills compared to PSN. In addition, PSE performed most compact and accurate skills in the conflicted operative space.

Background: The purpose of this study was to develop a new objective assessment system for the suture ligature method employed in the laparoscopic intestinal anastomosis model. Suturing skills were evaluated objectively using this system., Methods: This study compared 17 expert surgeons, each of whom had performed >500 laparoscopic procedures, with 36 novice surgeons, each of whom had performed <15 laparoscopic procedures. Each examinee performed a specific skill assessment task using an artificial model that mimics living tissue, which is linked with the Suture Simulator Instruction Evaluation Unit. The model used internal air pressure measurements and image processing to evaluate suturing skills. Five criteria were used to evaluate the skills of participants., Results: The volumes of air pressure leak in the expert and novice groups were 21.13 ± 6.68 and 8.51 ± 8.60 kPa, respectively. The numbers of full-thickness sutures in the expert and novice groups were 2.94 ± 0.24 pairs and 2.47 ± 0.77 pairs, respectively. Suture tensions in the expert and novice groups were 60.99 ± 11.81 and 80.90 ± 16.63 %, respectively. The areas of wound-opening in the expert and novice groups were 1.76 ± 2.17 and 11.06 ± 15.37 mm(2), respectively. The performance times in the expert and novice groups were 349 ± 120 and 750 ± 269 s, respectively. Significant differences between the expert and novice groups for each criterion were observed. The acceptable range of values for each criterion except for the number of full-thickness sutures was statistically defined by the performance of the expert group., Conclusions: Our system is useful for the quantitative assessment of suturing skill in laparoscopic surgery. We believe that this system is a useful tool for training and assessment of laparoscopic surgeons.

Introduction: This study presents the design of a novel single port laparoscopic surgery robot that is actuated by plate-spring-driven mechanisms with high force transmission and a larger workspace. Many ongoing studies aim to develop robotic single port laparoscopic surgery platforms due to the potential advantages in terms of a short recovery period and fewer postoperative scars. Most of these investigations of single port access have focused on resolving the inconvenient maneuverability of manual single port laparoscopic surgery. However, drive mechanism structures are another requirement., Materials and Methods: Most of the existing robotic platforms cannot transmit sufficient force, as many of them use wire-driven mechanisms, which are prone to mechanical deformation that also negatively affects the accuracy of the end effector. In addition, even the best-known laparoscopic surgical robot system has instruments with a limited workspace for single port laparoscopic surgery. Therefore, the purpose of this study was to propose a novel robotic single port laparoscopic surgery platform that uses plate springs to transmit higher forces during tissue handling., Results and Conclusion: Compared to wire- or link-driven mechanisms, the plate-spring mechanism provided surpassing force transmission, with >14 N force transmission achieved, which enables most laparoscopic surgery with single port access. In addition, the high degree of freedom structure of the proposed design permitted an expanded workspace, which might be the most competitive characteristic among the single port systems reported to date.

Background: The recent development of open magnetic resonance imaging (MRI) has provided an opportunity for the next stage of image-guided surgical and interventional procedures. The purpose of this study was to evaluate the feasibility of laparoscopic surgery under the pneumoperitoneum with the system of an open MRI operating theater., Methods: Five patients underwent laparoscopic surgery with a real-time augmented reality navigation system that we previously developed in a horizontal-type 0.4-T open MRI operating theater., Results: All procedures were performed in an open MRI operating theater. During the operations, the laparoscopic monitor clearly showed the augmented reality models of the intraperitoneal structures, such as the common bile ducts and the urinary bladder, as well as the proper positions of the prosthesis. The navigation frame rate was 8 frames per min. The mean fiducial registration error was 6.88 ± 6.18 mm in navigated cases. We were able to use magnetic resonance-incompatible surgical instruments out of the 5-Gs restriction area, as well as conventional laparoscopic surgery, and we developed a real-time augmented reality navigation system using open MRI., Conclusions: Laparoscopic surgery with our real-time augmented reality navigation system in the open MRI operating theater is a feasible option.

Background: We recently experienced 10 patients with cirrhosis who underwent laparoscopic splenectomy. A portion of these patients underwent dissection with a flexible endoscope in the peritoneal cavity. This pilot study mainly focused on the technical aspects and immediate results., Methods: From November 2009 to September 2010, 10 patients with cirrhosis and hypersplenism were entered into this pilot study. They were indicated to undergo laparoscopic splenectomy to treat portal hypertension and to facilitate initiation and completion of either interferon therapy for liver cirrhosis or anticancer therapy for hepatocellular carcinoma. To dissect the upper end of the gastrosplenic ligament and the marginal region between the left diaphragm and upper pole of the spleen, a flexible single-channel endoscope was introduced into the peritoneal cavity simultaneously with the use of a rigid laparoscope. Dissection with the flexible endoscope in the peritoneal cavity was performed using an insulation-tipped electrosurgical knife through the channel of the flexible endoscope., Results: The flexible endoscope offered a magnified operative view, a water-jet lens cleaner, and a powerful lavage and suction capability. The upper end of the gastrosplenic ligament and the marginal region between the left diaphragm and upper pole of the spleen were easily seen, and dissection of these critical regions was smoothly conducted with articulation of the tip of the flexible endoscope, even in patients with splenomegaly. No patient experienced major intraoperative complications or required conversion to open surgery., Conclusions: Dissection with a flexible endoscope in the peritoneal cavity may be an effective tactic for laparoscopic megasplenectomy, and significant implications for pure natural orifice translumenal endoscopic surgery have been raised. Although future randomized controlled prospective studies are needed to confirm these findings, surgeons might find this to be a typical example of an appropriate strategy for high-risk patients.

Background: Laparoscopic suturing skills are important for advanced laparoscopic surgery. However, objective assessment of these skills has not yet been established. The aim of this study was to assess the laparoscopic suturing skills of novice and experienced surgeons using an electromagnetic motion-tracking system., Methods: A total of 18 surgeons, who were all right-handed, were divided into the following two groups according to their experience as an operator in laparoscopic surgery: 9 novice surgeons (fewer than 10 laparoscopic procedures) and 9 experienced surgeons (more than 50 laparoscopic procedures). The subjects performed an intracorporeal suturing task in an inanimate box laparoscopic trainer while the movements of their forceps were evaluated using an electromagnetic motion-tracking system. Their laparoscopic skills were assessed on the basis of the time, path length, and average speed of the forceps in each hand., Results: Experienced surgeons completed the suturing task significantly faster than novice surgeons did. The left path length was significantly shorter for experienced surgeons than for novice surgeons, whereas the right path lengths did not differ. The right average speed of knot tying was significantly faster for experienced surgeons than for novice surgeons, whereas the left average speeds did not differ., Conclusions: Evaluation of psychomotor skills in laparoscopic suturing using an electromagnetic motion-tracking system revealed better results for experienced surgeons than for novice surgeons in terms of the time taken, left path length, and right speed of knot-tying. Furthermore, surgical proficiency due to experience can affect surgical dexterity of each hand differently. The present study also demonstrates the efficacy of this system for objective evaluation of laparoscopic suturing skills.

Background: Surgical navigation assists in endoscopic surgeries by enabling surgeons to see concealed lesions and surrounding organs. Successful surgical navigation depends on accurate registration between a medical image and a patient. For accurate point-based registration, it is important to determine the matching order and positions of the markers correctly. It is particularly difficult to determine the order and positions when part of the markers cannot be located on the patient's body or when they cannot be identified in the images., Methods: By using the automatic marker-matching option of the proposed tool, an optimum registration result can be obtained even with the partial loss of markers. In addition, this tool provides an intuitive marker selection interface that displays the registration error of each marker pair in different colors., Results: The efficiency of the described tool in terms of the registration accuracy and time has been confirmed in more than 70 clinical applications. The fiducial registration errors were 1.28 + or - 1.09 mm in ear, nose, and throat surgery and 3.55 + or - 1.30 mm in liver tumor ablation therapy., Conclusions: The proposed automatic matching scheme with marker selection interface was particularly effective where the markers were partly lost or incorrectly identified.

Background: To date, several training and evaluation systems for endoscopic surgery have been developed, such as virtual-reality simulators and box trainers. However, despite current advances in these objective assessments, no functional brain studies during learning of endoscopic surgical skills have been carried out. In the present study, we investigated cortical activation using near-infrared spectroscopy (NIRS) during endoscopic surgical tasks., Study Design: A total of 21 right-handed subjects, comprising 4 surgical experts, 4 trainees, and 13 novices, participated in the study. Suturing and knot-tying tasks were performed in a box trainer. Cortical activation was assessed in all subjects by task-related changes in hemoglobin (Hb) oxygenation using NIRS., Results: In surgical experts and novices with no experience of endoscopic surgical training, we found no changes in oxy-Hb, deoxy-Hb or total-Hb levels in any of the frontal channels. In surgical trainees and one novice with experience of endoscopic surgical training, we found significant increases in oxy-Hb and total-Hb levels in most of the frontal channels. There were significant differences in oxy-Hb and total-Hb levels in CH-19 between surgical experts and trainees (p = 0.02 for both), and between surgical trainees and novices with no experience of endoscopic surgical training (p = 0.008 for both). Furthermore, additional training increased oxy-Hb levels in the frontal cortex of novices with no experience of endoscopic surgical training but had no such effect on surgical experts., Conclusions: The present data suggest that NIRS is a feasible tool for assessing brain activation during endoscopic surgical tasks, and may have a large impact on the future development of teaching, training, and assessment methods for endoscopic surgical skills.

Background: As minimally invasive treatments for liver cancers, percutaneous ablation therapies represent a valid alternative to liver resections, especially in patients with poor liver function. Recently, image-guided surgical and interventional procedures using open magnetic resonance imaging (MRI) have been introduced., Methods: We performed percutaneous ablation therapy for 51 nodules of liver cancer in 34 patients using a navigation system based on open MRI. During the ablation therapy, the ultrasonography (US) probe, needle, and tumor were displayed on the MR image. Immediately after the procedure, the therapeutic effect was evaluated by open MRI., Results: In all cases, percutaneous puncture into the tumors was successful, even in the case of tumor undetectable by US. Mean fiducial registration error was approximately 3 mm. MR images captured after the procedure clearly demonstrated the ablated area. No mortality or major complications occurred, except for mild hemorrhage, pyrexia, and ascites., Conclusions: We developed a novel navigation system integrating US and MR images using open MRI for percutaneous ablation therapy of liver cancers. The presented system allows a safe and accurate approach to liver cancers, especially certain tumors that cannot be adequately visualized by US, and an evaluation of therapeutic results immediately after the procedures.

Background: Surgical navigation systems using an optical position sensor have the occlusion problem due to a person or instrument in the line of sight of the camera. In this study, occlusion-free real-time magnetic resonance (MR) scanning with a passive electromagnetic locator is proposed., Methods: A newly developed converter transforms the data of an electromagnetic locator into that of an optical sensor. Registration between the two different coordinate systems is performed for the electromagnetic locator to substitute the optical sensor without modifying the MRI system., Results: An oil marker attached to the electromagnetic locator was identified in real-time MR images. Preliminary results demonstrated the high usability of the electromagnetic locator as an alternative position tracking method in the MR gantry., Conclusions: The occlusion problem of optical sensors is resolved by the proposed method.

Background: This study was carried out to investigate whether eye-hand coordination skill on a virtual reality laparoscopic surgical simulator (the LAP Mentor) was able to differentiate among subjects with different laparoscopic experience and thus confirm its construct validity., Methods: A total of 31 surgeons, who were all right-handed, were divided into the following two groups according to their experience as an operator in laparoscopic surgery: experienced surgeons (more than 50 laparoscopic procedures) and novice surgeons (fewer than 10 laparoscopic procedures). The subjects were tested using the eye-hand coordination task of the LAP Mentor, and performance was compared between the two groups. Assessment of the laparoscopic skills was based on parameters measured by the simulator., Results: The experienced surgeons completed the task significantly faster than the novice surgeons. The experienced surgeons also achieved a lower number of movements (NOM), better economy of movement (EOM) and faster average speed of the left instrument than the novice surgeons, whereas there were no significant differences between the two groups for the NOM, EOM and average speed of the right instrument., Conclusions: Eye-hand coordination skill of the nondominant hand, but not the dominant hand, measured using the LAP Mentor was able to differentiate between subjects with different laparoscopic experience. This study also provides evidence of construct validity for eye-hand coordination skill on the LAP Mentor.