Supralesional and sublesional bone mineral density in spinal cord-injured patients

This study was performed to evaluate supra- and sublesional bone mineral de nsity (BMD) in spinal cord-injured (SCI) patients after 1 Scar postinjury, and to correlate the BMD to the neurological level; to correlate the subles ional demineralization to functional parameters (duration postinjury, durat ion of the initial bedrest); and to assess the role of classic methods of p revention such as walking or standing. Thirty-one SCI patients, all male, w ere studied vs, 31 controls (age matched). The mean age of the population w as 36 gears (range 18-60 years), Eleven were tetraplegic and 20 were parapl egic. Twenty-six patients dysplayed a complete motor lesion. The BMD was me asured by dual-photon absorptiometry on the lumbar spine and on the femoral neck, and the bone mineral content (BMC) on whole-body scans. Particular a ttention was paid to the distal femur and prosimal tibia upper third. Blood samples and urine samples included phosphocalcic parameters, with determin ation of urinary hydroxyproline and deoxypyridinoline. SCI patients showed a decrease of sublesional BRID of 41% in comparison with controls, This los s of hone mass is higher at the distal femur (-52%) and proximal tibia (-70 %), which are the most common sites of fracture. The degree of demineraliza tion for the lumbar spine, the pelvis, and the lower limbs is independent o f the neurological level, The duration of acute posttraumatic immobilizatio n (mean 33.3 days) and the time postinjury increase the loss of bone mass f or lower limbs (p = 0.04) and particularly for the proximal tibia (p = 0.02 ). The study of biomechanical stress (i.e., standing, walking, sitting) doe s not influence the sublesional BMC. This study underlines the major role o f the neurological lesion on the decrease of sublesional BMC in SCI patient s and the absence of influence of biomechanical stress. (C) 2000 by Elsevie r Science Inc. All rights reserved.