Objective: To optimize the flanged belt-loop technique of scleral fixation through biomechanical testing and report clinical outcomes of resultant modifications.
Design: Experimental study.
Methods: The force to disinsert flanged polypropylene suture from human cadaveric sclera was assessed using a tensile testing machine and compared to the breaking strengths of 9-0 and 10-0 polypropylene. The effects of modifying suture gauge (5-0, 6-0, 7-0, or 8-0), amount of suture cauterized (0.5 or 1.0 mm), and sclerotomy size (27, 30, 32, 33 gauge) were investigated. Belt-loop intrascleral fixation using 6-0 and 7-0 polypropylene with 30 and 32 gauge needles, respectively, was performed in 4 patients. Main outcome measures were flanged suture disinsertion forces in cadaveric sclera.
Results: The average force to disinsert a flange created by melting 1.0 mm of 5-0, 6-0, 7-0, and 8-0 polypropylene suture from human cadaveric sclera via 27, 30, 32, and 33 gauge needle sclerotomies was 3.0 ± 0.5 N, 2.1 ± 0.3 N, 0.9 ± 0.2 N, and 0.4 ± 0.1 N, respectively. The disinsertion forces for flanges formed by melting 0.5 mm of the same gauges were 72%-79% lower (P < .001). In comparison, the breaking strengths of 9-0 and 10-0 polypropylene were 0.91 ± 0.4 N and 0.52 ± 0.03 N. Belt-loop fixation using 6-0 and 7-0 polypropylene with 30 and 32 gauge sclerotomies demonstrated good outcomes at 6 months.
Conclusions: The flanged belt-loop technique is a biomechanically sound method of scleral fixation using 1.0 mm flanges of 5-0 to 7-0 polypropylene paired with 27, 30, and 32 gauge sclerotomies. In contrast, 8-0 polypropylene and 0.5 mm flanges of any suture gauge will likely be unstable with this technique.
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