Feasibility and safety of inserting transient biodegradable stents in the pylorus during pylorus-preserving gastrectomy for gastric cancer: a preliminary study in a porcine for proof of concept.

BACKGROUND: To evaluate whether insertion of self-biodegradable stent into the pylorus to prevent delayed-gastric emptying after pylorus-preserving gastrectomy is feasible and safe through porcine experiment. METHODS: Self-biodegradable dumbbell-shaped pyloric stents were designed from absorbable suture materials: poly(glycolide-co-caprolactone) (PGCL) or poly-p-dioxanone (PPDO). After gastrotomy on ten pigs, each stent was inserted: two shams, four PGCL stents, and four PPDO stents. Body weight (Bwt), body temperature (BT), complete blood cell (CBC) count, and plain X-ray were evaluated. On postoperative day (POD) 13, euthanasia was performed for histologic evaluation. RESULTS: Operation was successfully performed in all ten pigs. Without tagging suture, both stents migrated before POD 3. The migration was delayed up to POD 13, when the tagging sutures (-t) were applied between stent and stomach wall. Self-degradation of PGCL started from POD 3, and stents were completely excreted from the abdomen by POD 8. Although PPDO were also weakened as self-degradation progressed, its shape was maintained in gastrointestinal tract for 13 days. Unexpected sudden death occurred in the pig with PPDO-t2 on POD 10, which is more likely due to acute volvulus rather than stent-related complication. There was no significant difference between three groups in terms of Bwt, BT, CBC, and histology (sham vs. PGCL vs. PPDO, all p > 0.05). CONCLUSION: The concept of biodegradable stents made of absorbent suture material seems feasible in porcine experiment. Among them, PGCL which has shown rapid absorption, appears to be a more suitable material for transient pyloric absorbable stent when considering safety aspect.

Comparative study of rheological properties and preclinical data of porous polycaprolactone microsphere dermal fillers.

BACKGROUND: In this study, a physical properties test and preclinical evaluation were performed on two polycaprolactone (PCL)-based dermal filler formulas. OBJECTIVE: This study was performed to compare the rheological characteristics, preclinical efficacy, and safety of a new PCL filler, SF-01, with a licensed PCL filler. METHODS: First, the viscoelasticity of the PCL filler was evaluated. Next, hairless mice were injected with fillers and evaluated for efficacy with a folliscope and PRIMOSLITE . Histological evaluation was conducted for 6 months to evaluate safety. RESULTS: In this evaluation, SF-01 was superior to a licensed PCL filler in initial volume increase rate and in vivo durability, and the migration of the injected filler was not confirmed. The elasticity (G*, G') and viscosity (G'') are also expected to be lower than those of a licensed PCL filler, thereby resulting in less foreign body sensation in the living body. CONCLUSION: SF-01 (porous PCL microsphere-based dermal filler) has been confirmed to be superior in durability and shape retention compared to the licensed PCL filler (nonporous PCL microsphere-based dermal filler), and the in vivo safety is equivalent.