Osteoporosis after spinal cord injury

Immobilisation secondary to spinal cord injury (SCI) is associated with marked and rapid atrophy of trabecular bone. The purpose of this study was to evaluate bone mineral density (BMD) in both the upper and lower extremities following SCI sustained for various lengths of time and to correlate the BMD to the level of the lesion, time from injury, spasticity and serum calcium, phosphorus and alkaline phosphatase (ALP) levels. A study was undertaken in 41 SCI patients with a mean age of 35.8 +/- 12.7 years. A significant difference in BMD between upper and lower extremities of the paraplegics were found. BMD of upper and lower extremities were similar in tetraplegies. The BMD values were significantly different when the upper extremity scores of paraplegics and tetraplegics were compared but BMD scores of the lower extremities were similar in the two groups. The decrease in BMD was less in the spastic patients when compared to the flaccid group. There was a positive correlation between time from injury and the degree of BMD deficit in the paralysed areas. In the whole group of patients a significant positive correlation was found between the duration of SCI and serum ALP levels.