A comparison of methods of repairing the symphysis pubis in bladder exstrophy by tensile testing.

Objective: To compare the efficacy of several fixation techniques in the reconstruction of diastasis of the symphysis pubis in bladder exstrophy.
Materials and Methods: The symphysis of 32 pelves removed from piglets about 1 month old were disrupted and repaired using one of eight methods. After repair, each pelvis was tested biomechanically for load-to-failure, stiffness and energy-to-failure. The various repair techniques were compared with one another and to a group of six pelves tested intact.
Results: Four of the methods tested, including a #2 nylon suture placed through bone in a horizontal mattress arrangement, several loops of #2 nylon suture tied around the pubes, Mersilene tape tied around the pubes, and Mitek G-II suture anchors placed into the superior pubic rami, showed the highest stiffness and load-to-failure. All methods were very weak compared with the intact symphysis; the best load-to-failure (#2 nylon horizontal mattress suture) was less than half of that for intact bone, and the best stiffness (mersilene tape) was less than one-third that for the intact symphysis.
Conclusion: The repairs varied greatly in the variables tested and those which are most promising merit further investigation to assess methods of improving their performance.