Optimize bone health before a fusion
What the bone has to do for a fusion to take, which numbers your surgeon looks at before agreeing to operate, and what can be done in the months beforehand to improve them.
Optimize bone health for better fusion outcomes
A fusion only succeeds if the bone heals around the hardware and keeps its grip on the screws. When bone is thin, screws loosen, cages settle into the vertebra, and the fusion can fail to knit — so strengthening the bone beforehand is part of the operation, not an afterthought.
Spinal hardware is only as strong as the bone it anchors into. In osteoporotic bone, pedicle screws pull out or loosen more often, interbody cages can sink into the soft vertebral body (subsidence), and the fusion is slower and less certain to form a solid bridge — a higher risk of pseudarthrosis, or non-union. Longer, multi-level constructs carry the most bone-related risk, including new fractures at the top of the construct.
Before an elective fusion we take stock of the bone: a DEXA scan for a T-score, the density of a CT you may already have — in Hounsfield units — read at the levels we plan to instrument, and bloodwork for vitamin D and reversible causes of bone loss.
When the numbers are low and surgery is elective, the team may treat the bone first. The evidence differs by medicine. Teriparatide has been studied most in spine fusion, and a spine-surgery guideline supports considering it before an elective fusion in people with osteoporosis. Evidence for romosozumab in fusion is newer and comes mainly from looking back at past patients. Abaloparatide has been studied less in fusion. How long to treat before and after surgery, and what follows it, is decided for each person with a bone-health physician; there is no single timeline. Urgent or unstable cases are not delayed; there the bone is optimized around the operation instead.
Teriparatide and abaloparatide (daily injections) and romosozumab (monthly injections for a limited course) build new bone. Each has its own safety checks: for example, romosozumab is not started soon after a heart attack or stroke, and low calcium is corrected first.
Bisphosphonates & denosumab hold the gains afterward. Denosumab must never be stopped without a planned hand-off.
Anabolic first, antiresorptive second — the reverse blunts the anabolic’s effect.
Coordinated with a bone-health physician and weighed against surgical urgency. General education, not a prescription.
The numbers your surgeon watches
Thresholds teams use to decide when bone is weak enough to treat, and weak enough to optimize before an elective fusion.
DEXA T-score
A prior fragility fracture counts as osteoporosis on its own; DEXA can read falsely high over spinal arthritis.
CT Hounsfield units (L1)
Loose hardware, subsidence, and non-union rise as this falls; many surgeons flag < 120 HU at instrumented levels.
When we optimize first
- A prior fragility or vertebral fracture
- T-score ≤ −2.5, or L1 CT < ~120 HU
- High 10-year fracture risk (FRAX)
- A long or multi-level construct
Bone optimization is planned jointly by your spine surgeon and a bone-health physician, and is balanced against how urgent your surgery is. It does not replace individual medical advice.
This page is the bone-health half of the spinal fusion walkthrough, split out on its own for anyone who came here for the bone rather than the operation.