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Mechanical Testing of a Single Rod Versus a Double Rod in a Long-Segment Animal Model
- Source :
- Journal of Spinal Disorders. 14:232-236
- Publication Year :
- 2001
- Publisher :
- Ovid Technologies (Wolters Kluwer Health), 2001.
-
Abstract
- This study involved the mechanical testing of single-rod segmental hook fixation and double-rod segmental hook fixation in a long-segment animal model. The goals were first to compare the flexibility of a single-rod scoliosis construct with that of a double-rod construct when tested in torsion, and second, to determine the effect of not using instrumentation with every vertebral segment for the single rod. Another study found that the single-rod construct was as stiff in torsion as the standard double-rod construct in a model of 10 vertebral segments. The amount of neutral zone (NZ) rotation was tested in five calf spines using an MTS (Material Testing System) machine. Five constructs were tested and included 1) a single rod with hooks at every level except the apex; 2) a single rod with two fewer hooks; 3) a single rod with four fewer hooks; 4) a double-rod construct; and 5) no instrumentation. The amount of NZ rotation between vertebral segments was measured over 12, 10, 8, 6, 4, and 2 vertebral segments. An analysis of variance with all constructs showed that the instrumented spines had significantly less movement than did the uninstrumented spine. Statistical comparison using analysis of variance of constructs (constructs 1 to 4) showed that over 12 vertebral segments (T4-L3), all single-rod constructs (constructs 1 to 3) allowed more NZ rotation than did the standard double-rod construct. This testing indicated that over 12 vertebral segments the single rod allowed more NZ rotation than a double-rod construct.
- Subjects :
- Torsion Abnormality
Rotation
genetic structures
Hook
Scoliosis
Bone Nails
Animal model
Materials Testing
medicine
Animals
Range of Motion, Articular
Pliability
Rachis
Osteosynthesis
business.industry
Neutral zone
Biomechanics
Torsion (mechanics)
Anatomy
medicine.disease
Spine
Biomechanical Phenomena
Orthopedic Fixation Devices
Cattle
Surgery
sense organs
Neurology (clinical)
business
Subjects
Details
- ISSN :
- 08950385
- Volume :
- 14
- Database :
- OpenAIRE
- Journal :
- Journal of Spinal Disorders
- Accession number :
- edsair.doi.dedup.....2034f59b15939d91ee46161b770773a4
- Full Text :
- https://doi.org/10.1097/00002517-200106000-00008