Takeshi Ohdaira

Antifogging effects of a socket-type device with the superhydrophilic, titanium dioxide–coated glass for the laparoscope

BackgroundLens fogging during laparoscopic surgery extensively deteriorates operative field visibility and may provoke serious complications.MethodsA simulation model study was conducted using a conventional laparoscope, a conventional laparoscope plus heating (100°C, 10 s), a conventional laparoscope plus surfactant, and a conventional laparoscope plus both a titanium dioxide (TiO2)-coated glass (with ≥15 h of preoperative ultraviolet irradiation) and a water supply. For each, the time from laparoscope insertion into the peritoneal cavity to fogging-induced interruption of surgery was measured.ResultsThe TiO2-coated glass had unique verified properties of exerting antifogging effects on the oil film after 15 or more hours of previous ultraviolet irradiation, and of inversely accelerating fogging after less than 15 h of previous ultraviolet irradiation. The clinical study showed later fogging with the TiO2-coated glass model, which successfully completed surgery without retraction of the laparoscope from the peritoneal cavity, as compared with the other models.ConclusionAn antifogging device using superhydrophilic TiO2-coated glass was very effective in preventing fogging during laparoscopic surgery.

Intraoperative localization of colorectal tumors in the early stages using a marking clip detector system

In laparoscopic colectomy the identification of the site of a tumor is often difficult. The topical injection of india ink or blue dye by preoperative colonoscopy is the most prevalent method to mark the tumor site; however, such a procedure also includes the intrinsic danger of possibly injecting dye into the peritoneal cavity. In addition, the injected marker may also spread so widely that the intended site may become obscure. A marking clip detector system was used to detect metallic marking clips in the luminal side that had been applied to the mucosa adjacent to the lesion during the course of preoperative colonoscopy. This method was able to identify the marked site in 40 percent of cases in which only one clip was applied to the mucosa. However, when the lesion sites were marked with two or three clips, then the detection rate increased to 100 percent. Based on our findings, this procedure was found to be a safe and reliable method for identifying lesions during laparoscopic-assisted colectomy.

Development of a robotic system with six-degrees-of-freedom robotic tool manipulators for single-port surgery.

Current robotic systems have limitations for single‐port surgery (SPS) because the instruments are large, the arms collide and the field of vision requires manual readjustment. We have developed an SPS robotic system that manipulates the vision field.

Intraoperative localization of early-stage upper gastrointestinal tumors using a magnetic marking clip–detecting system

BackgroundIntraoperative tumor localization often is difficult during laparoscopic surgery for early-stage upper gastrointestinal tumors.MethodThis study enrolled 15 patients undergoing laparoscopic gastrectomy. A magnetic marking clip–detecting system was used to apply a marking clip to the tumor site during preoperative gastroscopy, and to detect a marking magnetic body.ResultsIn a basic ex vivo study, the mean permeance rate on the gastric wall serosal surface was 0.97 ± 0.01. Magnetic flux densities required for exploration were 52.6 mT on the gastric wall serosal surface and 312.4 mT 10 mm away from the surface. In a clinical study, the mean distance between the detected tumor site and the clip along the longitudinal axis was 8.3 ± 3.2 mm. The mean detection time was 5.7 ± 2.3 min.ConclusionThe magnetic marking clip–detecting system may be useful for tumor site detection during laparoscopic gastrectomy.

Estimation of intraoperative blood flow during liver RF ablation using a finite element method-based biomechanical simulation

Radiofrequency ablation is increasingly being used for liver cancer because it is a minimally invasive treatment method. However, it is difficult for the operators to precisely control the formation of coagulation zones because of the cooling effect of capillary vessels. To overcome this limitation, we have proposed a model-based robotic ablation system using a real-time numerical simulation to analyze temperature distributions in the target organ. This robot can determine the adequate amount of electric power supplied to the organ based on real-time temperature information reflecting the cooling effect provided by the simulator. The objective of this study was to develop a method to estimate the intraoperative rate of blood flow in the target organ to determine temperature distribution. In this paper, we propose a simulation-based method to estimate the rate of blood flow. We also performed an in vitro study to validate the proposed method by estimating the rate of blood flow in a hog liver. The experimental results revealed that the proposed method can be used to estimate the rate of blood flow in an organ.

In vivo experiments of a surgical robot with vision field control for single port endoscopic surgery

Recently, robotics systems are focused to assist in Single Port Endoscopic Surgery (SPS). However, the existing system required a manual operation of vision and viewpoint, hindering the surgical task. We proposed a surgical endoscopic robot for SPS with dynamic vision control, the endoscopic view being manipulated by a master controller. The prototype robot consists of a manipulator for vision control, and dual tool tissue manipulators (gripping: 5DOFs, cautery: 3DOFs) can be attached at the tip of sheath manipulator. In particular, this paper focuses on an in vivo experiment. We showed that vision control in the stomach and a cautery task by a cautery tool could be effectively achieved.

Significance of metacognitive skills in laparoscopic surgery assessed by essential task simulation

Abstract Background: Metacognition is the knowledge about ones own methods of perceiving, remembering, thinking, and acting. This study determined the significance of metacognitive skills in laparoscopic surgery with the aim of applying the findings in a laparoscopic surgery training program. Material and methods: Eighteen medical students with no experience in laparoscopic surgery (novice group) and eight expert surgeons who had each performed >100 laparoscopic surgeries (expert group) were enrolled. The examinees in each group performed an evaluation task using a virtual reality simulator and answered questions about the task. Results: The longest performance times, longest path lengths, and most frequent tissue damage occurred at 135° in the novice group and at 180° in the expert group. The greatest recognition of task difficulties, impatience, and irritation occurred at 135° in the novice group and at 180° in the expert group. There were statistically significant correlation coefficients between the instrument path length and task difficulty (metacognition) at 135° (R = 0.74, p = 0.03) and 180° (R = 0.79, p = 0.02) in the expert group, but there were no significant correlations in the novice group. Conclusion: We elucidated the significance of metacognitive skills in laparoscopic surgery. A training program should include recognition feedback systems.

Ultra-minimally invasive local immune cell therapy and regenerative therapy by multi-piercing surgery for abdominal solid tumor: therapeutic simulation by natural orifice translumenal endoscopic surgery-assisted needlescopic surgery using 3-mm diameter robots

Background/purposeWe have invented multi-piercing surgery (MPS) which could potentially solve the triangular formation loss and device clashing which occur in single-port surgery (SPS), as well as restricted visual field, organ damage by needle-type instruments, and impaired removal of a resected organ from the body which occur in needlescopic surgery (NS). MPS is natural orifice translumenal endoscopic surgery (NOTES)-assisted NS. We used 3-mm diameter robots as needle-type instruments for MPS to examine the possibility of local immune cell therapy and regenerative therapy using stem cells for pancreatic cancer.MethodsIn MPS using two robots, the therapeutic cell suspension was injected into a target region of pancreas in two pigs. Both retention of a capsule of liquid cell suspension and invasive level were evaluated.ResultsTriangular formation could be ensured. The use of small-diameter robots allowed (1) the surgical separation of the pancreas and the retroperitoneum, and (2) the formation of the capsule containing the immune cell and stem cell suspension. The endoscope for NOTES provided a clear visual field and also assisted the removal of a resected organ from the body. The visual field of the endoscope could be oriented well by using an electromagnetic navigation system.ConclusionsMPS using small-diameter robots could potentially solve the issues inherent in SPS and NS and could allow minimally invasive local immune cell and stem cell therapy.

Usefulness of a Flexible Port for Natural Orifice Transluminal Endoscopic Surgery by the Transrectal and Transvaginal Routes

We developed a flexible port for NOTES which allows the use of conventional forceps for laparoscope-assisted surgery without change. The port is not affected by the location of the through hole in the gastrointestinal tract or vagina which elicits a problem in conventional NOTES, and its length can be adjusted during surgery by cutting the port itself. The port is made of polymer resin with a low friction coefficient. Furthermore, the port walls have a square wave structure which contributes to (1) the prevention of devices, for example, endoscope, from getting stuck at the time of insertion and retrieval, (2) the prevention of port slippage in the surgical opening for port insertion, (3) the prevention of unexpected port removal, (4) the prevention of port bore deformation, and (5) the improvement of port flexibility in the longitudinal direction. We validated the insertion and retrieval capacities of commercially available forceps for laparoscope-assisted surgery and power devices. Furthermore, we used the flexible port to conduct cholecystectomy and partial gastrectomy. We could confirm that the selection of the flexible port diameter according to the device type allowed the smooth insertion and retrieval of the device and that the port produced no air leakage. We affirmed that it is possible to conduct surgery by the cross or parallel method similarly to single port surgery. We considered that the flexible port has a potential of becoming a revolutionary port in NOTES.

Validation of accuracy of liver model with temperature-dependent thermal conductivity by comparing the simulation and in vitro RF ablation experiment

Radiofrequency (RF) ablation is increasingly used to treat cancer because it is minimally invasive. However, it is difficult for operators to control precisely the formation of coagulation zones because of the inadequacies of imaging modalities. To overcome this limitation, we previously proposed a model-based robotic ablation system that can create the required size and shape of coagulation zone based on the dimensions of the tumor. At the heart of such a robotic system is a precise temperature distribution simulator for RF ablation. In this article, we evaluated the simulation accuracy of two numerical simulation liver models, one using a constant thermal conductivity value and the other using temperature-dependent thermal conductivity values, compared with temperatures obtained using in vitro experiments. The liver model that reflected the temperature dependence of thermal conductivity did not result in a large increase of simulation accuracy compared with the temperature-independent model in the temperature range achieved during clinical RF ablation.