Biomechanical effects of the extent of sacrectomy on the stability of lumbo-iliac reconstruction using iliac screw techniques: What level of sacrectomy requires the bilateral dual iliac screw technique?

Background: Although both single and dual iliac screw techniques are used in spino-pelvic reconstruction following sacrectomy for treating sacral tumors, the basis for choosing between the two techniques for different instability types remains undetermined. The purpose of this study was to evaluate the effects of the extent of sacrectomy on the stability of the lumbo-iliac fixation construct using single and dual iliac screw techniques.

Methods: Nine human L2-pelvic specimens were tested for their intact condition simulated by L3-L5 pedicle screw fixation.

Biomechanical advantages of dual over single iliac screws in lumbo-iliac fixation construct.

The development of iliac screws has provided a markedly easier way for spino-pelvic instrumentation than the classical Galveston technique. However, high rates of iliac screw loosening and breakage are usually reported, especially in cases where bilateral single iliac screws are used. Therefore, there is a need for exploring more stable iliac fixation techniques.

Effect of the degree of osteoporosis on the biomechanical anchoring strength of the sacral pedicle screws: an in vitro comparison between unaugmented bicortical screws and polymethylmethacrylate augmented unicortical screws.

Study Design: An in vitro laboratory study.

Objective: (i) To evaluate the effect of osteoporotic degree in determining the strength of sacral screw fixation and (ii) to compare the strength of unaugmented bicortical pedicle screw and polymethylmethacrylate (PMMA) augmented unicortical pedicle screw in sacral fixation.

Summary Of Background Data: Screw loosening is a clinical problem in lumbosacral fusions, especially in osteoporotic patients.

Biomechanical comparison of 4 fixation techniques of sacral pedicle screw in osteoporotic condition.

Study Design: An in vitro biomechanical cadaver study.

Objectives: To compare the subsidence displacement after cyclic loading among 4 sacral pedicle screw fixations of bicortical, tricortical, standard polymethylmethacrylate (PMMA) augmentation, and sub-endplate PMMA augmentation in osteoporotic condition.

Summary Of Background Data: Implant failure caused by screw loosening is a clinical problem for lumbosacral fusions, especially in osteoporotic patients.

The effect of screw length and bone cement augmentation on the fixation strength of iliac screws: a biomechanical study.

Study Design: Comparison of the biomechanical fixation strengths offered by 3 iliac screw fixation techniques: short screw, short screw augmented with cement, and long screw.

Objective: Evaluate the effect of screw length and bone cement augmentation on the fixation strength of iliac screw upon fatigue loading.

Summary Of Background Data: Iliac screws have been used in treating spinal disorders such as spinal deformity, spondylolisthesis, and sacral tumor.