Time-Dependent Changes in Biomechanical Properties of Four Different Synthetic Materials in a Rabbit Model and the Importance in Respect to Sling Surgery

Aim: To examine the time-dependent biomechanical properties of four different implanted synthetic materials. Materials and Methods: 18 New Zealand rabbits were randomly categorized into three groups: group 1 to be evaluated at the 2nd week, group 2 at the 8th week, and group 3 at the 12th week. Before the implantation, baseline values were obtained. Each of the 2 x 5 cm sized materials of mersilene, prolene, ultrapro and vypro mesh were placed in the anterior abdominal fascia. The mesh materials were removed, tensile strength (N/mm(2)) and ultimate strain (%) were measured by tensinometry and surface area losses (cm(2)) were calculated. Results: Tensile strength values (mean +/- SD) were 9.2 +/- 1.5, 8.5 +/- 1.2 for mersilene, 25.2 +/- 7.3, 14.0 +/- 2.9 for prolene, 2.2 +/- 0.6, 12.5 +/- 1.4 for ultrapro and 8.1 +/- 1.6, 7.0 +/- 1.8 for vypro at baseline and the 12th week. Ultimate strain values (mean +/- SD) were 131.2 +/- 46.1, 110.4 +/- 98.6 for mersilene, 181.0 +/- 26.4, 78.5 +/- 14.4 for prolene, 91.5 +/- 8.2, 89.6 +/- 20.5 for ultrapro and 84.3 +/- 8.9, 55.0 +/- 13.2 for vypro at baseline and the 12th week. Surface areas (mean +/- SD) were 8.87 +/- 0.14, 9.38 +/- 0.17, 8.4 +/- 0.32 and 8.76 +/- 0.16 for mersilene, prolene, ultrapro and vypro at the 12th week respectively. Conclusions: Although prolene mesh demonstrated a decrease in its tensile strength it still remains the highest at the 12th week. Considering the significant time-dependent increase in its tensile strength, ultrapro mesh should be studied in humans. A final decision on the preference of ultrapro mesh in sling surgery could be reached after such studies. Copyright (C) 2008 S. Karger AG, Basel