Human spinal height growth: a description of normal spine growth patterns and adult spine height prediction from a longitudinal cohort.

Purpose: This study describes spinal growth and predicts future growth by standardizing timing relative to the growth spurt.

Methods: From a longitudinal cohort of normal, healthy children followed through their growth, we identified those who completed their growth and compared spinal heights to chronological age and timing relative to the growth spurt. Anthropometrics and radiographs were correlated to identify heights to C1, T1, and S1 using three separate methods with validation performed by comparing to heights predicted by pelvic width. Heights and spinal lengths were normalized to percentages of adult lengths, and multipliers of growth remaining determined for both age and timing relative to PHV_90% (peak height velocity defined by achieving 90% of final height) as adult length divided by current spine length. The age at PHV_90% is termed Peak Growth Age (PGA)_90%.

Results: Fifty-four subjects completed their growth at the study terminus (35f, 19 m). We identified multipliers allowing calculations of adult spine length based on the child's current timing relative to peak growth. At PHV_90%, children were 90% adult total height and 87% adult spine height. During childhood, spinal growth is 1.55 ± 0.21 cm/yr in girls, 1.14 ± 0.23 cm/yr in boys increasing to 1.75 ± 0.11 cm/yr in girls and 2 ± 0.11 cm/yr in boys during the growth spurt.

Conclusion: This study identifies multipliers of spinal growth determination and identifies their values relative to the adolescent growth spurt timing which is known to be closely related to skeletal maturity. Timing compared to the PGA_90% provides reliable predictions of final spine length for both sexes.