Abstract
Purpose:
To assess how cannula size and cannula bevel angle effect silicone oil aspiration rates.
Methods:
In vitro aspiration rates of silicone oil 1000 and silicone oil 5000 using 20, 23, and 25 gauge cannulas, 23 and 25 gauge cannula adapters, and 20 gauge angiocaths cut beveled and unbeveled were measured. Aspiration rates were determined by timing fixed vacuum suction of silicone oil, then weighing the silicone oil with a precision analytical scale. Three timed trials were performed for each aspiration condition. The results were averaged and aspiration rates normalized to grams aspirated per minute.
Results:
Normalized aspiration rates (grams/minute) of silicone oil 1000 (fastest to slowest) were: 20 G beveled angiocath (5.96), 23 G trocar with adaptor (3.78), 20 G unbeveled angiocath (3.56), 23 G short tip cannula (2.96), 25 G trocar with adaptor (1.8), 25 G short tip cannula (1.22). Normalized aspiration rates for silicone oil 5000 (fastest to slowest) were: 20 G beveled angiocath (1.16), 23 G trocar with adaptor (0.77), 20 G unbeveled angiocath (0.66), 23 G short tip cannula (0.59), 25 G trocar with adaptor (0.35), 25 G short tip cannula (0.27).
Conclusions:
Aspiration rates of silicone oil are affected by silicone oil viscosity and cannula gauge. Beveling the 20 gauge angiocath tip nearly doubled the silicone oil aspiration rates. Among 23 and 25 gauge trocar systems, the trocar with adaptor demonstrated faster aspiration than short cannula systems.
Keywords: 762 vitreoretinal surgery •
763 vitreous •
688 retina