A novel technique for sacropelvic fixation using image-guided sacroiliac screws: a case series and biomechanical study.

Kee D Kim,Bandon Bucklen,Aditya Muzumdar,Huy Duong,Mark Moldavsky,Mir Hussain

doi:10.7555/jbr.32.20170077

Abstract

In this study, we sought to assess the safety and accuracy of sacropelvic fixation performed with image-guided sacroiliac screw placement using postoperative computed tomography and X-rays. The sacroiliac screws were placed with navigation in five patients. Intact specimens were mounted onto a six-degrees-of-freedom spine motion simulator. Long lumbosacral constructs using bilateral sacroiliac screws and bilateral S1 pedicle and iliac screws were tested in seven cadaveric spines. Nine sacroiliac screws were well-placed under an image guidance system (IGS); one was placed poorly without IGS with no symptoms. Both fixation techniques significantly reduced range of motion (P<0.05) at L5–S1. The research concluded that rigid lumbosacral fixation can be achieved with sacroiliac screws, and image guidance improves its safety and accuracy. This new technique of image-guided sacroiliac screw insertion should prove useful in many types of fusion to the sacrum, particularly for patients with poor bone quality, complicated anatomy, infection, previous failed fusion and iliac harvesting.

Highlights

Posterior lumbosacral instrumented fusion is widely used to treat spinal instability caused by a variety of conditions including degenerative disease, infection, tumor, trauma and deformity[1–3]
We evaluated the biomechanical parameters of sacroiliac I screws in cadavers with nondestructive range of motion (ROM) and flexibility testing
A total of nine sacroiliac screws were placed under image guidance system (IGS), and one without

Summary

Introduction

Posterior lumbosacral instrumented fusion is widely used to treat spinal instability caused by a variety of conditions including degenerative disease, infection, tumor, trauma and deformity[1–3]. When the instrumented construct is long and extends past the lumbar region, a large moment arm is placed on the caudal end, putting the construct at risk for fusion failure, instrumentation pullout, sacral fracture and loss of lordosis[4–5]. One commonly used approach to strengthen the caudal end of lumbosacral constructs is to extend fixation to the pelvis with the use of bilateral iliac screws. They are placed with bicortical purchase in an anterolateral direction from the posterior superior iliac spine into the hard cortical bone above the sciatic notch, thereby resisting the cantilever moment of the long construct at the cranial end[2,6]. The iliac screw heads are generally positioned lateral to the axis of lumbar/ sacral screws, and require additional bending

Methods

Results

Conclusion