A new method using a vessel-sealing system provides coagulation effects to various types of bleeding with less thermal damage.

BACKGROUND: Hemostasis is very important for a safe surgery, particularly in endoscopic surgery. Accordingly, in the last decade, vessel-sealing systems became popular as hemostatic devices. However, their use is limited due to thermal damage to organs, such as intestines and nerves. We developed a new method for safe coagulation using a vessel-sealing system, termed flat coagulation (FC). This study aimed to evaluate the efficacy of this new FC method compared to conventional coagulation methods. METHODS: We evaluated the thermal damage caused by various energy devices, such as the vessel-sealing system (FC method using LigaSure™), ultrasonic scissors (Sonicision™), and monopolar electrosurgery (cut/coagulation/spray/soft coagulation (SC) mode), on porcine organs, including the small intestine and liver. Furthermore, we compared the hemostasis time between the FC method and conventional methods in the superficial bleeding model using porcine mesentery. RESULTS: FC caused less thermal damage than monopolar electrosurgery's SC mode in the porcine liver and small intestine (liver: mean depth of thermal damage, 1.91 ± 0.35 vs 3.37 ± 0.28 mm; p = 0.0015). In the superficial bleeding model, the hemostasis time of FC was significantly shorter than that of electrosurgery's SC mode (mean, 19.54 ± 22.51 s vs 44.99 ± 21.18 s; p = 0.0046). CONCLUSION: This study showed that the FC method caused less thermal damage to porcine small intestine and liver than conventional methods. This FC method could provide easier and faster coagulation of superficial bleeds compared to that achieved by electrosurgery's SC mode. Therefore, this study motivates for the use of this new method to achieve hemostasis with various types of bleeds involving internal organs during endoscopic surgeries.

Balloon-Based Organ Retractor With Increased Safety and Reduced Invasiveness During Video-Assisted Thoracoscopic Surgery.

OBJECTIVES: In recent years, video-assisted thoracoscopic surgery (VATS) has increasingly become the preferred technique for thoracic surgery. However, the inherent characteristics of the lungs as large, soft, slippery, and delicate creates difficulties for pulmonary surgery. In this article, we outline the development and assessment of a balloon-based organ retractor for VATS via collaboration between medical and engineering personnel. METHODS: A dry lab trial and accompanying questionnaire assessment were performed by a group of thoracic surgeons. Objective pressure measurements were obtained, and animal experiment on pigs was performed. RESULTS: In the dry lab trial, use of the developed organ retractor required significantly less time and resulted in fewer difficulties than using a Cherry Dissector. The measured pressure per mm2 of the developed retractor was clearly lower than that for the Cherry Dissector. The questionnaire completed by the surgeons following the dry lab and animal experiments showed that most of the surgeons (7 surgeons out of 9) were satisfied with the quality of the balloon-based retractor based on a score of 3.13 ± 0.28 (mean ± standard deviation) out of 4.0. During the animal experiment, the balloon-based retractor provided stable and clear viewing with minimal need for adjustment. CONCLUSION: This balloon-based retractor could contribute to increased safety and less-invasive VATS.

Three-dimensional printing model of liver for operative simulation in perihilar cholangiocarcinoma.

3-dimensional printed liver was constructed using 3D vascular imaging in a patient with intrahepatic cholangiocarcinoma who underwent major hepatectomy. The reproducibility of 3D modeling by the latest imaging has been clarified and future preoperative simulation should be adramatically changed.

Enhanced airway stenting using a preoperative, three-dimensionally printed airway model simulation.

Three-dimensionally printed organ models that facilitate preoperative simulations have the potential to improve outcomes of surgical procedures. Here, we report a case involving a 54-year-old man diagnosed with lung cancer of the right upper bronchus that was invading the right main bronchus. A right upper lobectomy with carinoplasty was performed. Although complete excision of the tumor was achieved, exertional dyspnea redeveloped 4 months post-surgery. Chest computed tomography revealed that airway stenosis caused by granulation had deformed the airway. Ablation of the granulation and airway stenting was required to improve the patient's symptoms. Prior to performing airway stenting, a three-dimensionally printed airway model was constructed, and the Y-shaped silicone stent used was modified in accordance with the model. After stenting, both the right and left bronchi were preserved, and the patient's symptoms improved. The three-dimensional printed airway model enhanced the accuracy and safety of the airway stenting procedure performed.

Regeneration of esophagus using a scaffold-free biomimetic structure created with bio-three-dimensional printing.

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.

Correction: Regeneration of esophagus using a scaffold-free biomimetic structure created with bio-three-dimensional printing.

[This corrects the article DOI: 10.1371/journal.pone.0211339.].

Replacement of Rat Tracheas by Layered, Trachea-Like, Scaffold-Free Structures of Human Cells Using a Bio-3D Printing System.

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.

Three-dimensional (3D) bronchial tree model for bronchial resection with pulmonary segmentectomy.

There has been an increase in pulmonary segmentectomy procedures because of increased numbers of individuals with small lung cancer. However, it is difficult to identify the correct bronchus during surgery even with pre-operative three-dimensional (3D) computed tomography. We investigated using a 3D-printed model of the bronchi to prepare for bronchus resection during pulmonary segmentectomy. The model was useful to determine pre-operatively which bronchus should be transected, and being composed of a soft material it could be mobilized similarly to the actual bronchus during surgery. This simulation can increase surgeons' confidence to identify the correct bronchus during pulmonary segmentectomy.

Initial experience with a 3D printed model for preoperative simulation of the Nuss procedure for pectus excavatum.

The incidence of pectus excavatum has been estimated to be between 0.1% and 0.8% though a large autopsy series reports. After publication of the Nuss procedure for pectus excavatum, it became widely accepted. However, there are still some complications, such as over-correction and recurrence. To reduce differences in the procedure due to surgeons' experience level, preoperative simulation may be useful. Thus, we performed simulated surgery using a specific patient's three-dimensional (3D) chest wall model made by a 3D printer before operation. A 13-year-old male patient with a severe deformity of the chest underwent the Nuss procedure. As in the simulation, bars were inserted into the 5th and 7th intercostal spaces (ICS), leading to improvement of the chest wall. This simulation can increase surgeons' confidence to improve the deformity by determination of the number and insertion sites of bars.

Scaffold-free trachea regeneration by tissue engineering with bio-3D printing.

OBJECTIVES: Currently, most of the artificial airway organs still require scaffolds; however, such scaffolds exhibit several limitations. Alternatively, the use of an autologous artificial trachea without foreign materials and immunosuppressants may solve these issues and constitute a preferred tool. The rationale of this study was to develop a new scaffold-free approach for an artificial trachea using bio-3D printing technology. Here, we assessed the circumferential tracheal replacement using scaffold-free trachea-like grafts generated from isolated cells in an inbred animal model. METHODS: Chondrocytes and mesenchymal stem cells were isolated from F344 rats. Rat lung microvessel endothelial cells were purchased. Our bio-3D printer generates spheroids consisting of several types of cells to create 3D structures. The bio-3D-printed artificial trachea from spheroids was matured in a bioreactor and transplanted into F344 rats as a tracheal graft under general anaesthesia. The mechanical strength of the artificial trachea was measured, and histological and immunohistochemical examinations were performed. RESULTS: Tracheal transplantation was performed in 9 rats, which were followed up postoperatively for 23 days. The average tensile strength of artificial tracheas before transplantation was 526.3 ± 125.7 mN. The bio-3D-printed scaffold-free artificial trachea had sufficient strength to transplant into the trachea with silicone stents that were used to prevent collapse of the artificial trachea and to support the graft until sufficient blood supply was obtained. Chondrogenesis and vasculogenesis were observed histologically. CONCLUSIONS: The scaffold-free isogenic artificial tracheas produced by a bio-3D printer could be utilized as tracheal grafts in rats.