Bernhardt and Bridwell measured sagittal alignment on lateral radiographs of 102 subjects with normal spines. Using both Cobb angles and computerized segmental angulation from T1-2 to L5-S1, they defined normative values for thoracic kyphosis, lumbar lordosis, and the thoracolumbar junction. The study aimed to provide an objective reference for evaluating sagittal deformity in scoliosis.
Every time you contour a rod across the thoracolumbar junction, this paper defines what normal looks like.
When posterior instrumentation stops at L2, contour less than 5° of lordosis between T12 and L2 — the data show that zone is nearly straight. Extending to L3 requires only about 10° of lordosis contouring between T12 and L3. Below L2, lordosis rises steeply (L4-5 = -20°, L5-S1 = -28°), so contouring demands increase rapidly with each additional caudal level.
Before this paper, surgeons lacked segmental-level data to guide rod contouring. Composite Cobb angles could not tell you what was happening at individual disc levels. Bernhardt gave us the actual per-segment numbers.
One nuance worth knowing: the wide normal range (thoracic kyphosis 9°-53°, lordosis 14°-69°) means there is no single correct target. Use ranges, not means, when evaluating sagittal deformity in a scoliosis patient.
Bernhardt and Bridwell measured sagittal alignment on lateral radiographs of 102 subjects with normal spines. Using both Cobb angles and computerized segmental angulation from T1-2 to L5-S1, they defined normative values for thoracic kyphosis, lumbar lordosis, and the thoracolumbar junction. The study aimed to provide an objective reference for evaluating sagittal deformity in scoliosis.
Every time you contour a rod across the thoracolumbar junction, this paper defines what normal looks like.
When posterior instrumentation stops at L2, contour less than 5° of lordosis between T12 and L2 — the data show that zone is nearly straight. Extending to L3 requires only about 10° of lordosis contouring between T12 and L3. Below L2, lordosis rises steeply (L4-5 = -20°, L5-S1 = -28°), so contouring demands increase rapidly with each additional caudal level.
Before this paper, surgeons lacked segmental-level data to guide rod contouring. Composite Cobb angles could not tell you what was happening at individual disc levels. Bernhardt gave us the actual per-segment numbers.
One nuance worth knowing: the wide normal range (thoracic kyphosis 9°-53°, lordosis 14°-69°) means there is no single correct target. Use ranges, not means, when evaluating sagittal deformity in a scoliosis patient.