Purpose
A straight type back-flush needle is usually used in vitreous surgery, however contact of the back flush needle with the wide-angle viewing system may limit the working range. We developed a new 25G back-flush needle that can provide wider working range in the fundus than the regular straight type back flash needle. The purpose is to show the usefulness of the new back-flush needle through a simulation and actual vitrecotmy.
Methods
The new back flash needle is shown in the figure. We simulated the working range in the eye and compared the working range with that with the regular straight back-flash needle under three types of wide-angle viewing system including Peyman-Wessels-Landers (PWL), Resight and BIOM. We defined the visual axis as 0 degree, insertion side as minus degree and the opposite side as plus degree.
Results
In simulations of the regular straight back-flash needle, the working range was limited up to +29 degrees in PWL, +8 degrees in Resight and +2 degrees in BIOM. It was expanded up to -27 degrees, -20 degrees and -27 degrees, respectively. Thus, the hummingbird back-flash needle provides wider working range than the strait type back-flash needle. The wider working range in the hummingbird back-flush needle was confirmed in vitrectomy.
Conclusions
The new 25G hummingbird back-flush needle provides wider working range than straight type back flash needle under the wide-angle viewing system. It may be useful in vitrectomy under wide-angle viewing system.
Keywords: 762 vitreoretinal surgery