Whether or not multiple venous anastomoses reduce the risk of free-flap failure is a subject of controversy. We report here, for the first time, on the importance of selecting 2 separate venous systems of the flap for dual anastomoses. The efficacy of multiple anastomoses was verified through a retrospective review of 310 cases of the free radial forearm flap transfer. Dual anastomoses of separate venous systems (the superficial and the deep) showed a lower incidence of venous insufficiency than single anastomosis did (0.7% versus 7.5%; P < 0.05). On the other hand, dual anastomoses of a sole venous system showed no significant difference in the incidence of venous insufficiency compared with single anastomosis (11.5% versus 7.5%; P = 0.48). Our results suggest that dual venous anastomoses of separate venous systems is conducive to reduced risk of flap failure and affords protection against venous catastrophe through a self-compensating mechanism that obviates thrombosis of either anastomosis.
Micro-tribology is a key technology in micro-mechanics and the magnetic recording head-media interface. The atomic-scale surface state is very important in micro-tribology. However, the concepts of micro-tribological material design are not clear. The top-surface must be modified to improve micro-tribological properties. To improve adhesion and strength, hard carbon films containing silicon deposited by an electron cyclotron resonance (ECR) plasma depositor are examined for friction and wear using a reciprocating tribometer. Fluorinated silicon-containing films are deposited to reduce atomic-scale wear. Micro-tribological properties of this film are investigated by ultra-low load wear-testing, leading to the following conclusions: (1) The micro-tribological characteristics of silicon-containing carbon film are improved by fluorination. Fluorination decreases the surface energy, evaluated by contact angle to the water, and reduces the micro-wear on an atomic scale. (2) The adhesion to the substrate and the strength of the carbon film are greatly improved by adding small quantities of silicon. These films also have significantly longer lubricating lives.
Amorphous C:H containing silicon film shows an extremely low friction coefficient of 0.007 when the film is rubbed with a steel ball in a vacuum. This film is deposited on steel with an electron cyclotron resonance plasma of ethylene and silane. Polarized microinfrared spectroscopy reveals that high lubrication performance is attributed to hydrocarbons transferred from the rubbed film to the ball surface and oriented along the sliding direction.
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