Lumbar intervertebral motion in vivo: a preliminary comparison of recumbent and weight bearing motion patterns in adult males
Start date: 9 November 2012
Journal: Bone & Joint Journal Orthopaedic Proceedings Supplement
Issue: SUPP 17
Publisher: British Editorial Society of Bone and Joint Surgery
Study Purpose: A preliminary study to compare continuous sagittal plane lumbar inter-vertebral kinematics in 10 healthy volunteers in recumbent and weight bearing configurations using quantitative fluoroscopy.
Background: There are no direct in-vivo comparisons between continuous weight bearing and non-weight bearing inter-vertebral kinematics in the same healthy individuals. This information will advance our knowledge of spine mechanics and provide reference values for clinical studies.
Methods: Ten male healthy control volunteer subjects aged between 30 and 50 underwent a recumbent bending procedure during fluoroscopy. All participants repeated this in weight bearing. Trunk motion was controlled for range and velocity. Digital image sequences (DICOM) of these movements were captured at 15 fps and analysed using automated frame to frame image registration codes in MATLAB (Mathworks). Inter-vertebral motion characteristics, including inter-vertebral angular range of rotation and attainment rate (Laxity), were calculated.
Results: These results are the preliminary output of an ongoing study to create a reference database for normal spine kinematics. Comparisons of the motion patterns within and between participants will be demonstrated along with preliminary statistical analysis of range of motion and speed of attainment (laxity) of the angular range within the first 10o of trunk motion after the inter-vertebral motion starts. Laxity is proposed as a new in vivo proxy for the neutral zone where force is replaced by trunk motion near the neutral position.
Conclusion: These preliminary comparisons demonstrate the feasibility of establishing a reference database of lumbar spine kinematics to which patient populations can be compared, potentially allowing these to emerge as outcome measures.