We have successfully demonstrated miniature actuators that are capable of converting chemical potential directly into steady mechanical movements for maxillofacial distraction osteogenesis. Pistons and diaphragms powered by osmosis are employed to provide the desired linear and volumetric displacements for bone distraction and potentially the release of bone morphogenetic proteins, respectively. The cylindrical-shaped miniature actuators are composed of polymeric materials and fabricated by molding and assembly processes. In the prototype demonstration, vapor-permeable thermoplastic polyurethane was employed as the semi-permeable material. 3 cm long actuators with piston and diaphragm radii of 1 mm and 500 μm, respectively, were fabricated and characterized. The maximum distraction force from the piston-type actuator is found to be 6 N while the piston travels at a constant velocity of 32 μm h −1 (or 0.77 mm/day) for about 1 week. Meanwhile, the release rate from the diaphragm-type actuator is measured to be constant, 0.15 μl h −1 (or 3.6 μl/day), throughout the experiment. Moreover, the sizes and output characteristics of the self-regulating actuators could readily be tailored to realize optimal distraction rate, rhythm and osteogenic activity. As such, the demonstrated miniature osmotic actuators could potentially serve as versatile apparatuses for maxillofacial distraction osteogenesis and fulfill the needs of a variety of implantable and biomedical applications.

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Background Laparoscopic greater curvature plication (LGCP) is a new bariatric procedure that is similar to laparoscopic sleeve gastrectomy (LSG) in that it uses a restrictive mechanism. Comparative studies between LGCP and LSG were still limited. The aim of this study was to compare the clinical outcomes of the two procedures based on the same clinical conditions. Methods From January 2012 to December 2015, 260 patients with morbid obesity underwent LGCP and LSG in a single center. Data on patient demography, operation time, complications, hospital stay, body mass index loss, percentage of excess weight loss (%EWL), and improvement in comorbidities were collected. A propensity-matched analysis, incorporating pre-operative variables, was used to compare the short-term outcomes between LGCP and LSG. Results Propensity matching produced 48 patients in each group. Patients who underwent LGCP were predominately female (75.5%, 41.1% of the LSG patients were female, p = 0.028). Baseline BMI and excess weight were significantly lower in the LGCP group (p < 0.001). The LSG group showed a greater decrease in excess body weight than the LGCP group (

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The authors thank the Center of Continuing Education from the Kaohsiung Medical University and all of the participants who supported their research efforts and shared their time and experiences with them.