Current Advances in Three-Dimensional Tissue/Organ Printing

Three-dimensional (3D) tissue/organ printing is a major aspect of recent innovation in the field of tissue engineering and regenerative medicine. 3D tissue/organ printing aims to create 3D living tissue/organ analogues, and have evolved along with advances in 3D printing techniques. A diverse range of computer-aided 3D printing techniques have been applied to dispose living cells together with biomaterials and supporting biochemical factors within pre-designed 3D tissue/organ analogues. Recent developments in printable biomaterials, such as decellularized extracellular matrix bio-inks have enabled improvements in the functionality of the resulting 3D tissue/organ analogues. Here, we provide an overview of the 3D printing techniques and biomaterials that have been used, including the development of 3D tissue/organ analogues. In addition, in vitro models are described, and future perspectives in 3D tissue/organ printing are identified.

The Learning Curve for Totally Extraperitoneal (TEP) Repair in Inguinal Hernia / 대한내시경복강경외과학회지

PURPOSE: Laparoscopic totally extraperitoneal (TEP) repair has been increasingly used for the treatment of inguinal hernias. This procedure is a very difficult technically and it requires a great deal of experience. However, there are only few studies on the learning curve (LC) of this procedure in the Korea literature. The aim of this study is to determine the number of case that are needed to overcome the learning curve of TEP hernia repairs and to document the surgical and clinical differences before and after overcoming the LC. METHODS: This study retrospectively reviewed 96 TEP hernia repairs that were performed by a single surgeon. The time required to overcome the LC was determined by examining the operation time. The preoperative and postoperative clinical data, such as incidental intraoperative findings, the rate of operative morbidity, the rate of conversion to an open procedure and the length of the postoperative hospital stay, were compared between the before and after groups with overcoming the LC. RESULTS: The 40th case was determined to be the transition point of overcoming the LC according to the operation time. The time before overcoming the LC averaged 73.0 minutes compared to 55.6 minutes after overcoming the LC. The postoperative hospital stay and the conversion rate were all significant (p<0.05). However, the other postoperative outcomes did not show significant differences. CONCLUSION: Based on the plateau of the operative time, this study shows that the downward slope of LC for TEP repair is at the 40th operation.

Gastric Outlet Obstruction due to Submucosal Neurofibromatous Proliferation of Duodenal Bulb in Neurofibromatosis Type 1 Patient

Neurofibromatosis type 1 (NF1; also known as von Recklinghausen's neurofibromatosis) is inherited in an autosomal dominant fashion, although it can also arise due to spontaneous mutation. Gastrointestinal involvement of NF1 is seen in 10% to 25% and causes symptoms in fewer than 5%. Histologically, the gastro intestinal (GI) manifestation of NF1 occurs in three forms: hyperplasia of the gut neural tissue, stromal tumors, and duodenal or periampullary endocrine tumors. A 31-year-old female, diagnosed with NF1, presented with poor oral intake and vomiting for 10 days prior to admission. Preoperative gastrofiberscopic finding was gastric outlet obstructing polypoid duodenal bulb lesion. The patient underwent hemigastrectomy with antecolic gastrojejunostomy due to gastric outlet obstruction. The final pathologic report was submucosal neurofibromatous proliferation with Brunner's gland hyperplasia located at the duodenal bulb in the NF1 patient. We report this case with a review of literatures.