We developed a modified dissector capable of carrying out a one-hand operation involving three fundamental functions: grasping, sharp or blunt dissection, and dividing the tissues. With this single dissector, laparoscopic cholecystectomy can be rapidly and safely performed without changing the forceps or instruments through the trocar.

A clear field of vision during laparoscopic cholecystectomy was attained by using a newly designed retractor which elevates the abdominal wall and does not require high-pressure CO2 infusion into the peritoneal cavity. As the abdominal cavity is continuously ventilated, smoke from the cauterization is suctioned off through openings in the middle part of the retractor. There is no interference with placement of ports.

Current scaffold‐based tissue engineering approaches are subject to several limitations, such as design inflexibility, poor cytocompatibility, toxicity, and post‐transplant degradation. Thus, scaffold‐free tissue‐engineered structures can be a promising solution to overcome the issues associated with classical scaffold‐based materials in clinical transplantation. The present study seeks to optimize the culture conditions and cell combinations used to generate scaffold‐free structures using a Bio‐3D printing system. Human cartilage cells, human fibroblasts, human umbilical vein endothelial cells, and human mesenchymal stem cells from bone marrow are aggregated into spheroids and placed into a Bio‐3D printing system with dedicated needles positioned according to 3D configuration data, to develop scaffold‐free trachea‐like tubes. Culturing the Bio‐3D‐printed structures with proper flow of specific medium in a bioreactor facilitates the rearrangement and self‐organization of cells, improving physical strength and tissue function. The Bio‐3D‐printed tissue forms small‐diameter trachea‐like tubes that are implanted into rats with the support of catheters. It is confirmed that the tubes are viable in vivo and that the tracheal epithelium and capillaries proliferate. This tissue‐engineered, scaffold‐free, tubular structure can represent a significant step toward clinical application of bioengineered organs.

Various strategies have been attempted to replace esophageal defects with natural or artificial substitutes using tissue engineering. However, these methods have not yet reached clinical application because of the high risks related to their immunogenicity or insufficient biocompatibility. In this study, we developed a scaffold-free structure with a mixture of cell types using bio-three-dimensional (3D) printing technology and assessed its characteristics in vitro and in vivo after transplantation into rats. Normal human dermal fibroblasts, human esophageal smooth muscle cells, human bone marrow-derived mesenchymal stem cells, and human umbilical vein endothelial cells were purchased and used as a cell source. After the preparation of multicellular spheroids, esophageal-like tube structures were prepared by bio-3D printing. The structures were matured in a bioreactor and transplanted into 10-12-week-old F344 male rats as esophageal grafts under general anesthesia. Mechanical and histochemical assessment of the structures were performed. Among 4 types of structures evaluated, those with the larger proportion of mesenchymal stem cells tended to show greater strength and expansion on mechanical testing and highly expressed α-smooth muscle actin and vascular endothelial growth factor on immunohistochemistry. Therefore, the structure with the larger proportion of mesenchymal stem cells was selected for transplantation. The scaffold-free structures had sufficient strength for transplantation between the esophagus and stomach using silicon stents. The structures were maintained in vivo for 30 days after transplantation. Smooth muscle cells were maintained, and flat epithelium extended and covered the inner surface of the lumen. Food had also passed through the structure. These results suggested that the esophagus-like scaffold-free tubular structures created using bio-3D printing could hold promise as a substitute for the repair of esophageal defects.

Between April and August 1991, 83 Japanese patients with symptomatic gallstones underwent laparoscopic cholecystectomy in our clinics. A prospective randomized trial was carried out to examine the safety, efficacy, and complications of the two techniques, pneumoperitoneum vs an elevating method using a U-shaped retractor. Forty-two patients were randomly allocated to the pneumoperitoneum (P) group and 41 to the U-shaped retractor (U) group. These two groups were well matched with respect to age, sex, etiology, and the severity of the chronic cholecystitis. Laparoscopic resection was successful for 88.1% (37/42) in the P group and 100% (41/41) in the U group. In patients with a severe fibrotic gallbladder, the rate of success was significantly higher (P < 0.05) in the U group (100%, 6/6) than in the P group (11.8%, 1/6). In the moderately inflamed group, the operation time (mean +/- SD) was significantly (P < 0.01) less in the U group (58.7 +/- 22.7) than in the P group (87.3 +/- 18.3). With the U-shaped retractor the usual surgical instruments can be used, and a rapid and safer laparoscopic cholecystectomy can be carried out. We prefer this approach to a pneumoperitoneum for patients with an inflamed gallbladder as hospital stay and pain are minimal.