Related Experiment Videos
Sacral screw loads in lumbosacral fixation for spinal deformity
R S Pashman1, S S Hu, M J Schendel
1Department of Orthopaedic Surgery, University of Minnesota, Minneapolis.
Spine
|December 1, 1993
Summary
Sacral screws in spinal deformity surgery experience both axial loads and bending moments during flexion. Understanding these forces is crucial for improving fixation and preventing implant failure in spinal fusion procedures.
Area of Science:
- Spine surgery
- Orthopedic biomechanics
- Spinal instrumentation
Background:
- Sacrum and pelvis fixation is a challenge in operative spinal deformity treatment.
- In vivo loading conditions for pedicle screws are not well understood, despite testing of pull-out strength.
Purpose of the Study:
- To determine the in vivo loads experienced by sacral screws during Cotrel-Dubousset (CD) instrumentation.
- To investigate if anterior grafting methods influence sacral screw loading.
Main Methods:
- Sacral screws were modified into transducers to measure axial and bending loads.
- Screw transducers were integrated into CD instrumentation in seven calf spines.
- Specimens were subjected to simulated flexion loading.
Main Results:
- Sacral screws sustained both axial loads (1.1 N/[Nm of load]) and bending moments (1.1 Nm/[Nm of load]).
- Screw loading was independent of the anterior graft types utilized.
Conclusions:
- Bending forces may play a significant role in sacral screw failure.
- Grafting techniques did not alter the loading experienced by sacral screws in this model.