Abstract
Purpose: :
To examine the effects of high speed cutting on peak velocity and peak acceleration of aspirated aqueous fluid using a dual pneumatic vitrectomy probe
Methods: :
Flow of 7cc/min aqueous solution and microbeads through a 25-gauge cutter was studied in a pressurized closed-system test chamber that simulated the tissue compliance and pressure response of an eye. Two high speed cameras were orthogonally oriented around the eye-model test chamber and simultaneously recorded microbead motion into the probe port at 2500 and 5000 cpm. Frame-by-frame analysis of microbeads from both camera perspectives was used to determine average 3-D velocity and acceleration values. All data were analyzed using a Student’s t-test
Results: :
Average velocity and acceleration of microbeads aspirated at 2500 and 5000 cpm increased as microbeads approached the probe port. Maximum peak velocity of microbeads prior to port entry was 52.98 ± 11.89 mm/s for 2500 cpm and 42.06 ± 10.51 mm/s for 5000 cpm. Maximum peak acceleration of microbeads prior to port entry was 5442.46 ± 1479.84 mm/s2 at 2500 cpm and 2909.88 ± 538.82 mm/s2 at 5000 cpm. The 2500 cpm cut rate generated approximately 24% faster average peak velocities (P<0.05) and approximately 35% higher average peak accelerations than 5000 cpm (P<0.05).
Conclusions: :
Reduced peak velocities and peak accelerations of aqueous solution at 5000 cpm suggest that high cut rates may be associated with reduced pulsatile forces, pulsatile vitreoretinal traction and therefore iatrogenic retinal breaks
Keywords: vitreoretinal surgery • retinal detachment