Biomechanical Study of Canine Spinal Fracture Fixation Using Pins or Bone Screws With Polymethylmethacrylate

摘要

Stabilization of spinal fractures with pins and poly-methylmethacrylate (PMMA) is an effective method of treatment. However, optimal conformation of the fixation components has not been determined. The effects of pin number and angle and the use of pins vs. screws on the strength and rigidity of PMMA fixation were studied. Radiographically normal spines were dissected from 30 mature Greyhounds and were assigned to 1 of 5 experimental treatment groups or 1 control group. Experimental fracture-luxations were induced in all experimental spines. Stabilization was accomplished using PMMA injected into the PVC tubing (internal diameter, 16 mm and 3.2- X 65-mm trochar-point smooth Steinmann pins or 3.5- X 65-mm cortical screws in the following arrays: 4 or8 pins angled 70 degrees away from the fracture, 4 or 8 pins angled 70 degrees toward the fracture, or 4 screws angled away from the fracture. The force and angular deformation required to induce 10 degrees of deformation or implant failure were determined for each spine.