Spinopelvic Fixation Techniques

Abstract

umbosacral pelvic fixation and fusion procedures have been used to treat back pain caused by lumbar instability at the level of L5-S1; and coronal or sagittal deformities and pelvic obliquity to achieve balanced spine; also, when it is needed to increase rigidity of fixation in long fusions for degenerative reasons. (9)(33)(53) The lumbosacral pivot point is that point at the middle osteoligamentous column between the last lumbar vertebra and the sacrum. Only those devices that extend anterior to this pivot point provide a significant biomechanical advantage regarding rigidity of fixation. The farther that the implants extend anterior to this point, the greater the stiffness of the construct is. (8)(33) There are many clinical indications for sacropelvic fixation, including long fusions extending to the sacrum, flat-back deformity requiring corrective osteotomy, correction of pelvic obliquity, high-grade (Grade III or higher) spondylolisthesis, sacrectomy, sacral fractures with spinopelvic dissociation, and substantial osteoporosis in the setting of lumbosacral fusion. (29) Many different types of instrumentation and fixation devices are available for lumbosacral and spinopelvic fixation. Some are only of historical interest, whereas others are used frequently in the current armamentarium of spinal surgeons. Properly applied spinal instrumentation maintains alignment and shares spinal loads until a solid, consolidated fusion is achieved.(11) The concept of intrasacral rods has been introduced depending on the iliac buttress effect described by Jackson in 1993. So the rods are implanted in the area of the sacrum buttressed by the ilium, which results in an improved resistance to flexion bending moment. This system has the advantage of not crossing the sacroiliac joint. However, it is not an option for patients who do not have large enough sacral masses or those