Effect of spinal fusion on growth of the spine and lower limbs in girls with adolescent idiopathic scoliosis: a longitudinal study.

Two-hundred thirty-eight Southern Chinese girls, aged 10 to 14 years, treated previously for adolescent idiopathic scoliosis were studied longitudinally from the commencement of their treatment until maturity. Their standing, sitting, and suprasternal heights were measured at each follow-up visit, and their lower limb, head-neck, and spinal lengths were calculated. The results in 113 girls treated by posterior spinal fusion and Harrington instrumentation were compared with those of 125 girls who were treated with a brace. At maturity, the mean standing height of girls who underwent spinal fusion was not significantly different from that of patients treated with a brace. The fusion group had significantly shorter spinal lengths (p = 0.001), but significantly greater leg lengths (p = 0.001) compared to those of the brace group. Their arm lengths were similar, however. The girls who underwent spinal fusion had progressively increasing leg/arm ratios postoperatively from bone age 14-15 years onward compared to those treated with a brace, which indicated disproportionately longer legs in the girls who had spinal fusion. These findings suggest that spinal fusion performed on the girls with adolescent idiopathic scoliosis did retard the longitudinal growth of the spine. The standing height was unaffected, however, as the loss in spinal length was compensated by an increase in leg length.