Optimizing lumbar therapy: a biomechanical study of oblique pulling manipulation under different postures

Abstract Background While oblique pulling manipulation has proven to be an effective conservative treatment approach for lumbar disc herniation, it is not without limitations. One of the primary drawbacks of this technique is the potential for inaccurate localization during the procedure. This study aims to explore the effects of the oblique pulling manipulation under different lumbar postures and to characterize the resulting load distribution across different lumbar regions. Methods/study design This study employed a multi-modal approach combining infrared optical motion capture, finite element modeling, and biomechanical experiments. Eighteen healthy volunteers were divided into three groups for motion capture analysis of the oblique pulling manipulation at different angles. A finite element model of the lumbar spine was developed based on CT scans of a 24-year-old male volunteer and validated against existing literature. Biomechanical experiments were conducted on six cadaveric specimens using a BOSE testing machine to simulate the manipulation technique. Pressure measurements in the intervertebral discs and facet joints were obtained using a Tekscan pressure sensor. Results The experimental results showed that the biomechanical effects of oblique pulling manipulation were closely related to lumbar posture. Infrared optical motion capture, finite element modeling, and biomechanical experiments consistently demonstrated posture-dependent, region-specific loading patterns, with peak forces preferentially concentrated around the L3/4 region in extension, the L4/5 region in flexion, and the L5/S1 region in excessive flexion. These findings suggest that adjusting lumbar posture may influence the regional distribution of mechanical loads and provide a biomechanical basis for posture-guided application of oblique pulling manipulation. Conclusion These findings provide a biomechanical basis for posture-guided application of oblique pulling manipulation and may assist clinicians in selecting appropriate manipulation postures for patients with lumbar disc herniation.