Koichiro Murakami

Preliminary clinical experiences of a motorized manipulator for magnetic resonance image-guided microwave coagulation therapy of liver tumors.

BACKGROUND In magnetic resonance (MR) image-guided microwave thermocoagulation of liver tumors, the choice of the optimal puncture route is an important and time-consuming process. To assist this process, we have developed a motorized MR-compatible manipulator. METHODS The manipulator consists of a passive end effecter with 2 degrees-of-freedom (DOF) rotation and active base stages with 3 ultrasonic motors. It automatically chases the preset target point with synergetic remote-center-of-motion (RCM) control. A mechanical torque limiter and an electrical shutdown switch were added for patient safety. RESULTS The manipulator was used for this procedure in 15 cases and successfully utilized to treat liver tumors in various locations. Thoracoscopic assistance was combined with the manipulator in 6 cases. No complications were experienced. CONCLUSIONS The manipulator was found to be very effective for assisting MR-guided microwave coagulation of liver tumors.

Utility of a microwave surgical instrument in sealing lymphatic vessels.

BACKGROUND This study assessed the ability of a novel microwave coagulation surgical instrument (MWCX) to seal lymphatic vessels when compared with LigaSure (Valleylab, Boulder, CO), the Harmonic Scalpel (HS; Ethicon Endo-Surgery, Cincinnati, OH), and electric cautery. METHODS The burst pressure of pig inguinal lymphatic vessels was assessed after the sealing of vessels with each surgical instrument. The rate of lymphorrhea from pig mesenteric lymphatic vessels was also investigated using indocyanine green and visualized with the Photodynamic Eye system (Hamamatsu Hotoniks, Hamamatsu, Japan). RESULTS Burst pressures were higher with MWCX (average, 300 mm Hg), LigaSure (average, 290 mm Hg), and HS (average, 253 mm Hg) when compared with electric cautery (average, 152.3 mm Hg; vs MWCX: P = .002, vs LigaSure: P = .002, vs HS: P = .004). The rate of lymphorrhea was significantly lower with LigaSure (13.3%), HS (18.8%), and MWCX (13.3%) when compared with electric cautery (77.3%; vs LigaSure: P < .001, vs HS: P < .001, vs MWCX: P < .001). CONCLUSIONS MWCX was equivalent to LigaSure and HS in terms of the ability to seal lymphatic vessels.

Lymphoepithelial cyst with sebaceous glands of the pancreas: a case report

BackgroundLymphoepithelial cyst (LEC) of the pancreas is a rare benign tumor. LEC with sebaceous glands of the pancreas is extremely rare, and its histogenesis remains unclear.Case presentationWe present a 66-year-old man with an incidental finding of a cystic lesion at the neck of the pancreas. Pancreatic juice cytology results and elevated serum carbohydrate antigen 19-9 and Dupan-2 levels indicated that the cyst was a potential adenocarcinoma. Therefore, a pancreaticoduodenectomy was performed. Macroscopically, the tumor was a unilocular cyst with a thin transparent wall, filled with soft yellow material. Pathological findings showed that the cyst was lined with squamous epithelium, accompanied by dense lymphoid tissue with scattered germinal centers. There were no hair follicles, but sebaceous glands were present in the lymphoid tissue just beneath the squamous epithelium. Therefore, the histopathological diagnosis was an LEC with sebaceous glands of the pancreas. Furthermore, the squamous epithelium surrounding the cyst was pathologically continuous with the tubular structure, indicating that the tubular structure transitioned into the squamous epithelium.ConclusionsWe report an extremely rare case of LEC with sebaceous glands of the pancreas. Moreover, the pathological findings, which showed that the tubular structure transitioned into the squamous epithelium, suggested that this was squamous metaplasia. In order to investigate the histogenesis of LEC of the pancreas, the pathological findings must be evaluated.

Construct of Learning Model for Laparoscopic Surgery.

Laparoscopic surgery is one of surgery method. It requires many experiences to acquire the techniques and time to educate others because, for example, it has little information that the operator can acquire through field of view and sense of touch, and need to get used to through the operation of forceps. Laparoscopic surgery have four learning method (Dry box, Wet lab, Simulator, animal lab). With the simulator, learnings are that immersed in the most realistic skills, training environment, gave the opportunity to develop proficiency in laparoscopic surgical techniques, provided accurate tactile, feel of need procedures and complications and gave risk–free learning before touching their first patient. However, it is impossible to train according to personal skills only simulator. Previous studies have shown that the surgeon’ gaze point revealed when using the surgery simulator, thereby indicating that the result of the eye movement is useful for learning. The goal of this study is construction of learning system that to feedback the evaluation result to the learner. We analyzed the medical students’ eye movements, there were individual differences in the medical students’ gazing points, and there was a pattern in the medical students’ gazing points. We were able to cluster them and divide them into groups.

Lymphoepithelioma-Like Cholangiocarcinoma Associated With HCV: A Case Report and a Review of the Literature

Lymphoepithelioma-like carcinoma is a particular form of undifferentiated carcinoma characterized by a prominent lymphoid stroma that was originally described in the nasopharynx. We present a case of hepatitis C virus (HCV)–associated lymphoepithelioma-like cholangiocarcinoma (LEL-CC), located at the liver, in a patient with history of malignancy. A 79-year-old man underwent partial hepatectomy with lymphadenectomy for a suspected metastasis of colon cancer 2.5 years after hemicolectomy for advanced colon cancer followed by adjuvant chemotherapy. The resected tumor was diagnosed as LEL-CC via a distinct histologic pattern with dense lymphoplasma cell infiltration. According to the available literature, our report describes a rare cases of HCV-associated LEL-CC that coexisted with other malignancy and that was associated with survival for more than 3 years after surgery, suggesting that surgical resection may be the recommended therapeutic option for LEL-CC to provide a definitive diagnosis as well as obta...

Thermal tissue change induced by a microwave surgical instrument in a rat hepatectomy model

BACKGROUND Microwaves exhibit great potential in tissue heating, which causes effective coagulation. Using this energy, we have developed the microwave coagulation surgical instrument (MWCX) for clinical application. Here, we characterized the impact of MWCX on tissues including heating property, tissue change, and spread of thermal injury. METHODS Hepatectomy was performed with MWCX using a rat model. The resections were completed using various energy levels and powers. Tissue temperature during radiation was recorded. Tissue change and lateral thermal injury (LTI) was assessed immediately, 7 days, 3 months, and 6 months after resection. RESULTS All cutting and hemostasis procedures were successfully accomplished. Major histologic findings consisted of deformation or destruction of hepatocytes, tissue edema, and peripheral hemorrhage. At various energy levels, 200 to 1000 J, the tissue was heated up to approximately 80°C to 140°C causing 2.7- to 6.5-mm LTI on the 7th day. LTI was then decreased gradually in the following term. At certain energy levels, the application of neither 20 W nor 40 W induced significant difference in both heating and LTI. CONCLUSIONS MWCX achieved effective tissue coagulation with relevant tissue injury, and it should be a good candidate for clinical application.