Ex Vivo Biomechanical Comparison of Silicone Sling Securing Methods for Frontalis Ptosis Repair

In silicone sling frontalis suspension surgery, the sling is secured by passing both ends through a tight sleeve. Slippage of the silicone sling through the sleeve is likely a major reason for surgical failure. This ex vivo study compared different securing methods to improve the security of the sling in the sleeve.

This quantitative laboratory study compared 6 methods of securing the sling and sleeve to the control: 1) sutures to join the sleeve and sling, 2) 2-throw and 3) 3-throw square knots with the sling, 4) ligaclips, 5) cyanoacrylate surgical glue, and 6) a heat-shrink polyolefin sleeve. Tensile strength in Newtons (N) was measured to determine the force required to either initiate tail slippage or cause complete breakage of the silicone sling.

The securing methods, ranked by tensile strength, were: 3-throw square knot (4.3 N ±0.3), 2-throw square knot (3.7 N ±0.4), sutures (2.7 N ±0.5), ligaclips (1.3 N ±0.3), heat-shrink (1.1 N ±0.4), glue (0.6 N ±0.1), and control (0.2 N ±0.0). All methods, except glue, were significantly more effective than the control group.

Multiple methods can greatly improve the security of the sling within the sleeve in these laboratory tests. However, further in vivo exploration is needed to assess other factors such as biocompatibility, risk of extrusion, adjustability, and prominence under the brow. The aim is to develop a quick and easy method to apply while allowing for safe removal or loosening to adjust lid height without introducing additional risks.