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Telemeterized load measurement using instrumented spinal internal fixators in a patient with degenerative instability
A Rohlmann1, G Bergmann, F Graichen
1Department of Biomechanics, Free University Berlin, Germany.
Spine
|December 15, 1995
Summary
Internal spinal fixation device loads were measured in vivo. After anterior stabilization, loads increased significantly during activities like sitting and standing, indicating a need to avoid certain movements post-surgery.
Area of Science:
- Spinal biomechanics
- Orthopedic implant technology
- In vivo load measurement
Background:
- Previous spinal load studies relied on mathematical models or intradiscal pressure measurements.
- In vivo measurement of loads on internal spinal fixation devices has not been previously reported.
Observation:
- Telemeterized AO spinal internal fixators were implanted in a patient with degenerative instability.
- The device enabled in vivo measurement of forces and moments within the implant.
Findings:
- Implant loads were minimal during relaxed lying positions before and after anterior stabilization.
- Anterior stabilization led to significantly higher axial forces and bending moments (5-8 Nm) during sitting, standing, and walking.
- The highest loads were observed during transitional movements, such as turning from supine to lateral.
Implications:
- Patients should avoid upper body flexion, lateral bending, and weight-bearing activities in the initial months after anterior spinal stabilization.
- These findings provide crucial data for optimizing rehabilitation protocols and implant design for spinal fixation devices.