Spinebuild — Ortho Conditioning

Spinebuild

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Measurements

Add a wedge to make Predicted diverge from Pre.

Age (years)Empty = Schwab. Set age for Lafage PI−LL / PT / SVA.

	Pre	Pred	Target	Δ
Sacral slope SS = PI − PT. The sacral platform you stand on.	—	—	—	—
Pelvic tilt Compensatory. High PT is pelvic retroversion to keep the head over the hips.	—	—	< 20°	—
Pelvic incidence Morphologic constant. Does not change with posture or surgery.	—	—	—	—
Lumbar lordosis L1–S1. GAP ideal is 0.62×PI + 29, not always PI itself.	—	—	≈ 0.62×PI+29	—
L4–S1 Distal lordosis. About two-thirds of LL lives in L4–S1.	—	—	≈ ⅔ LL	—
L1–L4 Proximal lumbar. The remaining third above L4.	—	—	—	—
L4–S1 / LL L4–S1 as a share of L1–S1. GAP: the distribution, not just the Cobb.	—	—	50–80%	—
T4–T12 TK T4–T12 kyphosis. The thoracic half of the inflection.	—	—	—	—
TPA T1–pelvic angle at the hips. Global, and it does not need a millimetre scale.	—	—	—	—
PI − LL The mismatch to correct. Schwab: \|PI − LL\| < 10°. Age-adjusted when you set age.	—	—	0°	—
T1 slope Cervical and thoracic takeoff. Rises as the patient leans forward.	—	—	—	—
SVA Global balance. Schwab: C7 plumb within 40 mm of S1. Older spines are allowed more.	cal.	cal.	< 40 mm	—
cSVA	cal.	cal.	—	—
CBVA	—	—	—	—

Plan line

Spinebuild is an educational planning aid, not a medical device. Numbers are not a diagnosis or a surgical plan. Do not upload patient identifiers. SeeSpine topicsfor the teaching behind the measurements.