A Study of the Biomechanical Properties of the Adult Equine Linea Alba: Relationship of Tissue Bite Size and Suture Material to Breaking Strength

Abstract

The purposes of this study were to mechanically determine the optimal tissue bite size and to evaluate seven suture materials at their largest commercially available size for breaking strength and stiffness using cadaveric adult equine linea alba. Soft tissues were removed from the abdominal fascia of 16 adult horses. Individual test sections were created from the entire linea alba and labeled (1 through 6) starting at the umbilicus and extending craniad. A single biomechanical test was performed on each test section. Tissue bite size (3, 6, 9, 12, 15, 18, and 21 mm) significantly altered breaking strength directly in a logarithmic fashion (P < .0001; R²= 0.94). Tissue bite size accounted for 44% and linea alba thickness for 24% of the variability in breaking strength of the equine linea alba. The optimal tissue bite size for adult horses was 15 mm from the edge of the linea alba based on lack of significant gain in breaking strength. There were no differences in breaking strength among horses, horses weight, or left and right test sections. Test sections taken from near or at the umbilicus had greater breaking strength (P < .005) and thicker linea alba (P < .001) when compared with more cranial test sections. Linea alba thickness alone accounted for 34% of the variability in breaking strength associated with test section position. There were no differences in linea alba stiffness among tissue bite sizes. All suture loops failed before complete fascial disruption, and 52 of 56 (93%) suture loops failed at the knot. Suture breaking strength and stiffness were significantly affected by the type of suture material examined (P < .0001). Size 5 polyester had a greater breaking strength and stiffness compared with the other suture materials tested. The next strongest suture materials were size 3 polyglactin 910 and size 2 polyglycolic acid, which were similar in breaking strengths and stiffness. Size 2 nylon was significantly weaker in breaking strength when compared with the other suture materials.