PURPOSE: To design an endoscopic manipulator for fetal surgery. The viscoelastic properties of fetal skin were estimated from both the viewpoint of mechanical structure and data collection for controlling the device. METHODS: The skin of fetal Wistar rat (19.5 days old) was set on a rheometer and the relationship between stress and strain was examined. Morphological damage was assessed histologically. RESULTS: The stress-strain curve was nonlinear and sigmoidal throughout the process. The skin fracture point was estimated to be over 4 kPa. After multiple challenges of low-level loading under 150 Pa, the curve showed no detectable change due to mechanical fatigue. Histologically, the basement membrane was not damaged even at the fracture point; however, severe damage to the dermis was observed. CONCLUSION: The viscoelastic properties of the fetal rat skin were mainly caused by the dermis and the value of the shear stress that causes skin fracture was estimated to be 4 kPa. To design a robotic stabilizer, limit of mechanical loading was thus tentatively set at 400 Pa, with a 1/10 fracture point.
PURPOSE: To design an endoscopic manipulator for fetal surgery. The viscoelastic properties of fetal skin were estimated from both the viewpoint of mechanical structure and data collection for controlling the device. METHODS: The skin of fetal Wistar rat (19.5 days old) was set on a rheometer and the relationship between stress and strain was examined. Morphological damage was assessed histologically. RESULTS: The stress-strain curve was nonlinear and sigmoidal throughout the process. The skin fracture point was estimated to be over 4 kPa. After multiple challenges of low-level loading under 150 Pa, the curve showed no detectable change due to mechanical fatigue. Histologically, the basement membrane was not damaged even at the fracture point; however, severe damage to the dermis was observed. CONCLUSION: The viscoelastic properties of the fetal rat skin were mainly caused by the dermis and the value of the shear stress that causes skin fracture was estimated to be 4 kPa. To design a robotic stabilizer, limit of mechanical loading was thus tentatively set at 400 Pa, with a 1/10 fracture point.
Authors: E Danzer; M P Johnson; R D Wilson; A W Flake; H L Hedrick; L N Sutton; N S Adzick Journal: Ultrasound Obstet Gynecol Date: 2004-11 Impact factor: 7.299
Authors: Steven F Fowler; Roman M Sydorak; Craig T Albanese; Diana L Farmer; Michael R Harrison; Hanmin Lee Journal: J Pediatr Surg Date: 2002-12 Impact factor: 2.545
Authors: M R Harrison; N S Adzick; M T Longaker; J D Goldberg; M A Rosen; R A Filly; M I Evans; M S Golbus Journal: N Engl J Med Date: 1990-05-31 Impact factor: 91.245