Abstract
Purpose :
This study seeks to elucidate temperature changes in vitreous and surrounding tissues when utilizing a new hypersonic vitrector during simulated surgery.
Methods :
Surgery was simulated using a porcine eye model and a Stellaris EliteTM Vision System equipped with a VitesseTM Hypersonic Vitrector (HV). Vitreous temperatures were monitored continuously with an intravitreal thermocouple inserted through a 23ga cannula. Vitrectomy was performed under continuous operation of the HV at constant stroke rate, vacuum, and infusion pressure (n=3 handpieces for each condition). Stroke for the HV is defined as the distance the needle tip oscillates when active (0-60 µm). The thermocouple was kept within 1 µm of the HV tip during each trial, and temperature was recorded every 15 seconds for a total of four minutes. Additionally, thermal imaging was performed using a FLIR SC320 camera in order to determine the temperature changes in tissue around the HV insertion cannula during simulated surgery.
Results :
All tested groups saw an elevation in midvitreal temperature during simulated surgery. The correlation was statistically significant (p=0.001). The maximum mean temperature was 29.1 ± 0.4°C (Stroke: 60 µm, Vacuum: 0 mmHg, Infusion: 35 mmHg; n=3) with a rise in mean temperature of 7.6 ± 0.4°C. Thermal imaging also revealed a temperature increase in tissue directly adjacent to the HV insertion cannula in all tested groups. The highest mean temperature recorded was 27 ± 0.6°C (Stroke: 60 µm, Vacuum: 350 mmHg, Infusion: 35 mmHg; n=3) with a mean rise in temperature of 5.4 ± 0.1°C. The correlation was statistically significant (p=0.001). Data analysis revealed that when vacuum is constant, mean temperature increases as stroke increases. Conversely, when stroke is held constant, mean tissue temperature generally decreases as vacuum increases, most likely due to rapid heat dissipation by aspirated fluid.
Conclusions :
Vitrectomy under continuous operation of an HV handpiece causes temperature elevation in vitreous and surrounding tissues. However, highest mean temperature of tested groups were well within normal biologic temperatures (<37°C), demonstrating safety and efficacy of this new technology.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.