Deformable Biomechanics of DMEK Tissue Scrolls Traveling Through Narrow Lumens II: Double Scrolls Do Not Behave Like Single Scrolls.

Abstract

Purpose: To investigate and compare the dimensional characteristics of Descemet membrane endothelial keratoplasty (DMEK) scrolls in single-scroll and double-scroll conformations at various ages and velocities.

Methods: DMEK tissues from three donor pairs (ages 47, 62, and 69) were used to compare single-scroll and double-scroll widths under different velocities. Tissues were randomized and manipulated into single-scroll or double-scroll conformation using a syringe pump connected to an hourglass-shaped glass tube. All scrolls were passed through the tube at three different velocities set by syringe pump settings, and high-speed videography at 2000 frames per second captured scroll dimensions. Scroll dimensions were measured using IDT Motion Studio software.

Results: Single-scrolled DMEK tissue was narrower than double-scrolled tissue across all donor ages. Double-scrolled tissue width remained relatively unchanged regardless of age or velocity. Significant differences in scroll width between single and double scrolls were observed in the 47-year-old donor tissue at all velocities (P <0.001). Significant scroll width differences between single and double scrolls were observed in the 62-year-old donor tissue at medium and high velocities (P = 0.03 and P = 0.01, respectively). In the 69-year-old donor tissue, significant differences in scroll width between single and double scrolls were observed only at high velocities (P = 0.003). Single-scroll width decreased with increasing velocity for 47-year-old and 62-year-old donor tissues (P <0.001, P = 0.03), but not for the 69-year-old donor tissue (P = 1.0).

Conclusions: There is a significant difference in scroll width between single-scrolled and double-scrolled tissues at high speeds. These differences become less significant as scrolls increase in age and velocity decreases.