| STUDY DESIGN: In vivo biomechanical study. OBJECTIVES: To measure lumbar intervertebral disc pressure in vivo before, during and after high velocity low amplitude (HVLA) spinal manipulation. SUMMARY OF BACKGROUND DATA: HVLA spinal manipulation is commonly used in the treatment of low back disorders. However, little is known of its biomechanical effects on the lumbar intervertebral disc. METHODS: This study was reviewed and approved by the Institutional Review Board of the Palmer Center for Chiropractic Research. A pressure transducer was inserted into the nucleus pulposus of one normal-appearing lumbar disc (L3-4) in an asymptomatic adult volunteer. Pressures were recorded during several body positions and maneuvers, then during the application of HVLA spinal manipulation, and lastly during a repetition of the pre-intervention body positions. RESULTS: Baseline pressures in the prone and side lying positions measured 110 kPa and 150 kPa respectively. Pressure in the manipulative position prior to thrust measured 500 kPa. During the manipulative thrust the pressure rose to a peak of 890 kPa over 250 msec. Immediately following the thrust, pressures in the prone and side lying positions measured 150 and 165 kPa respectively. CONCLUSIONS: The peak pressures measured during the manipulation positioning and thrust were similar to pressures previously measured for sitting unsupported and sitting flexed respectively. Measuring lumbar intervertebral disc pressure in vivo during HVLA spinal manipulation is technically possible and may lead to a better understanding of this treatment method. ACKNOWLEDGEMENT: Supported by the Foundation for Chiropractic Education and Research This abstract is reproduced with the permission of the publisher. |
