Biomechanical Comparison of Spinopelvic Fixation Constructs: Iliac Screw Versus S2-Alar-Iliac Screw.

Autor: Burns CB; Department of Orthopaedic Surgery, Stony Brook University School of Medicine, Stony Brook, NY 11794, USA., Dua K; Department of Orthopaedic Surgery, Stony Brook University School of Medicine, Stony Brook, NY 11794, USA., Trasolini NA; Department of Orthopaedic Surgery, Stony Brook University School of Medicine, Stony Brook, NY 11794, USA., Komatsu DE; Department of Orthopaedic Surgery, Stony Brook University School of Medicine, Stony Brook, NY 11794, USA., Barsi JM; Department of Orthopaedic Surgery, Stony Brook University School of Medicine, Stony Brook, NY 11794, USA. Electronic address: James.barsi@stonybrookmedicine.edu.
Jazyk: angličtina
Zdroj: Spine deformity [Spine Deform] 2016 Jan; Vol. 4 (1), pp. 10-15. Date of Electronic Publication: 2015 Dec 23.
DOI: 10.1016/j.jspd.2015.07.008
Abstrakt: Study Design: Biomechanical cadaveric study.
Objective: To compare the biomechanical properties of the iliac and S2-Alar-Iliac (S2AI) screw in a similar spinopelvic fixation construct.
Summary of Background Data: Spinopelvic fixation is used in the correction of pelvic obliquity, high-grade spondylolisthesis, and long spinal fusions. With the development of pedicle screw fixation, the iliac screw has been used as an anchor point to the pelvis. The associated morbidity with this fixation has led to the development of the S2AI screw. Many studies have examined the biomechanical properties of iliac and S2AI screws; however, a direct comparison has not been performed.
Methods: Eight cadaveric spines were instrumented with pedicle screws bilaterally at L5 and S1. Four specimens were further instrumented with iliac screws placed with a starting point at the posterior superior iliac spine, and four specimens were instrumented with S2AI screws placed with a starting point 1 mm inferolateral to the S1 foramen. Screws were connected with 6.35 mm rods. Subfailure testing was performed by loading at 1°/second to a torque of 10 Nm in four directions: left bending, right bending, extension, and flexion. Specimens then underwent a monotonic load to failure under flexion at a rate of 1°/second.
Results: There were no significant differences for torsional stiffness in extension, flexion, left bending, or right bending between S2AI and iliac screw constructs. There were no significant differences in S2AI versus iliac screws for failure torque (30.9 ± 12.00 Nm vs. 22.61 ± 6.25 Nm) and yield torque (11.86 ± 0.41 Nm vs. 12.01 ± 1.70 Nm).
Conclusion: Iliac screws have been associated with increased dissection, wound complications, an additional construct failure point, and hardware prominence. The S2AI screw was developed as an alternative and has been associated with less morbidity. The iliac and S2AI screw demonstrate no statistical difference in stiffness and load-to-failure in a spinopelvic fixation model.
Level of Evidence: Level V.
(Copyright © 2016 Scoliosis Research Society. Published by Elsevier Inc. All rights reserved.)
Databáze: MEDLINE
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