Regional changes in bone mineral density following spinal cord injury in children.

OBJECTIVE

To document the serial changes in bone mineral density (BMD) following paediatric spinal cord injury (SCI).

DESIGN

Retrospective case series.

SETTING

Paediatric tertiary care hospital.

PATIENTS

Eighteen children (nine males) followed in an outpatient spinal cord injury service.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURE

Serial bone mineral density (BMD) measurements using dual energy X-ray absorptiometry (DXA).

RESULTS

Mean follow-up was 5.0 +/- 3.6 years (range 0.4-12.4 years). Three children sustained minimal trauma fractures, all femoral. For the cohort, BMD Z-scores were significantly less than zero in the legs (-2.7 +/- 2.0, p < 0.001), femoral neck (-2.1 +/- 1.4, p < 0.001), total body (-0.8 +/- 1.3, p=0.02) and lumbar spine (-0.8 +/- 1.6, p=0.04), but not in the arms (-0.2 +/- 1.0, p=0.5). Lean tissue mass (LTM) Z-scores were reduced in the legs (-1.9 +/- 1.3, p < 0.001). Longitudinal data showed an initial decline in lower extremity BMD, BMC and LTM aged-matched Z-scores in the 12 months following SCI, followed by an age appropriate increase thereafter.

CONCLUSIONS

Lower extremity osteopenia and sarcopenia develop rapidly in the first 12 months following the SCI. The reduced bone strength increases the risk of low trauma fracture.