Melville, N.Y., June 9, 2006

          Direct measurements of disc pressure ^(1,2) establish quantitatively that the forces on the recumbent intervertebral disc are only a fraction of what they are on the upright disc. Indeed, on the basis of these direct in vivo measurements of disc pressure it would appear that an examination of the patient lying down is not a relevant examination for the patient experiencing back pain when he is upright⁽³⁾. Indeed the data strongly suggests that the recumbent-only MRI carries the very real prospect of either grossly underestimating the patient's spinal pathology because the forces causing it have been removed, or not seeing the pathology at all for the same reason.

The data prove unequivocally that for the approximately 9,000,000 patients scanned annually in the MRI for upright back pain (3), the FONAR Upright™ MRI examination is the relevant examination.                     In 1999, H. J. Wilke et al.(1)at the Institute for Orthopedic Research and Biomechanics, University of Ulm, Germany reported direct in vivo measurements of pressures in the intervertebral disc in 28 body positions (Table 1) utilizing a pressure transducer implanted directly in the nucleus pulposus of a healthy non-degenerated L4-L5 disc of a male volunteer.           The direct measurements of disc pressure by Wilke et al.(1)show unequivocally that the recumbent disc is subject to a pressure that is only a tiny fraction of the pressure exerted on that same disc when the patient is standing and bending forward. Indeed, the pressure exerted on the disc when the patient is standing erect and bending forward is 11 times what the pressure is on the disc when the patient is recumbent.            Additionally, the data corroborates the original intradiscal pressure measurements made by Nachemson et al.(2)on the L3-L4 disc of volunteers (Fig. 2 from Nachemson et al.).

Table 1. Intradiscal Pressure Values for Different Positions and Exercises- (Wilke et. al 1999 Spine 24, #8, p.755) Position Pressure(MPa) Lying supine 0.10 Lying on the side 0.12 Lying prone 0.11 Lying prone, extended back, supporting on elbows 0.25 Laughing heartily, lying laterally 0.15 Sneezing, lying laterally 0.38 Peaks by turning around 0.70–0.80 Relaxed standing 0.50 Standing, performing vasalva maneuver 0.92 Standing, bent forward 1.10 Sitting relaxed, without backrest 0.46 Sitting actively straightening the back 0.55 Sitting with maximum flexion 0.83 Sitting bent forward with tight supporting the elbows 0.43 Sitting slouched into the chair 0.27 Standing up from a chair 1.10 Walking barefoot 0.53–0.65 Walking with tennis shoes 0.53–0.65 Jogging with hard street shoes 0.35–0.95 Jogging with tennis shoes 0.35–0.85 Climbing stairs, one stair at a time 0.50–0.70 Climbing stairs, two stairs at a time 0.30–1.20 Walking down stairs, one stair at a time 0.38–0.60 Walking down stairs, two stairs at a time 0.30–0.90 Lifting 20 kg, bent over with round back 2.30 Lifting 20 kg as taught in back school 1.70 Holding 20 kg close to the body 1.10 Holding 20 kg, 60 cm away from the chest 1.80 Pressure increase during night (over a period of 7 hr) 0.10–0.24 .1MPa = 14.5 lbf/in2 (pounds of force per square inch)