Spinal fusion does not necessarily make you shorter, and in many cases it actually makes you taller. The direction and degree of height change depend almost entirely on what condition prompted the surgery. Patients with scoliosis, kyphosis, or other spinal deformities often gain measurable height when their curves are straightened. Those undergoing fusion for degenerative disc disease at one or two levels may see little change either way.
When Spinal Fusion Makes You Taller
The most dramatic height gains happen in surgeries that correct spinal deformity. A 2023 study in The Journal of Bone & Joint Surgery tracked 198 adults who underwent surgery for spinal deformity and found that 74% of them gained height afterward. The average gain was 7.6 cm, or about 3 inches. That increase came from straightening the trunk (about 3.8 cm) and from improved lower-extremity alignment (about 3.3 cm), with smaller contributions from the cervical spine.
Scoliosis correction in younger patients produces consistent gains as well. In a study of 36 patients with idiopathic scoliosis (average age 16.7), the mean height gain was about 28.5 mm, or just over an inch. Patients with larger curves that were corrected more aggressively gained the most. A preoperative curve averaging 47.6 degrees was reduced to about 12.4 degrees, and each fused disc level contributed roughly 2 mm of height restoration. The logic is straightforward: a curved spine is shorter than a straight one, the same way a bent ruler measures less end to end than when it’s flat.
When Fusion Restores Lost Disc Height
For patients with degenerative disc disease, collapsed discs are a major source of height loss over time. Spinal fusion often involves placing an interbody cage, a small structural spacer, into the disc space to restore its height. In lumbar fusions using expandable cages, the front of the disc space gains an average of 8.6 mm immediately after surgery, while the back gains about 6.7 mm. That translates to meaningful local height restoration at the treated level.
However, some of that height settles over time. At 12 months, the front disc height in one study had decreased from 17.4 mm to 14.6 mm, still well above the preoperative average of 9.0 mm. This settling, called subsidence, happens when the cage migrates slightly into the adjacent bone. A systematic review found that subsidence occurs in roughly 13% to 27% of patients across different fusion techniques, with most cases being mild (a few millimeters). In a small percentage of patients, subsidence is more significant, exceeding 4 mm or becoming symptomatic.
For a single-level or two-level fusion, the net effect on your standing height is minimal either way. You might gain a fraction of a centimeter from restored disc height, or lose a similar amount from settling. Most patients wouldn’t notice the difference on a tape measure.
Why Some Patients Do Lose Height
A large study of adult spinal deformity patients who underwent long-segment fusion found an average spinal height change of negative 2.6 mm, but with enormous variation: some patients lost up to 160 mm (over 6 inches) while others gained up to 172 mm. That wide range reflects the diversity of conditions being treated and how the spine responds to correction. In cases where the spine is shortened intentionally to relieve tension on the spinal cord, or where significant bone is removed, height loss is expected and planned.
A more common long-term concern is what happens to the levels above and below the fusion. Fused vertebrae no longer move, so the neighboring segments absorb extra stress. Over time, this accelerates wear on those adjacent discs and joints, a condition called adjacent segment disease. About 16.5% of patients develop symptomatic problems at five years, rising to 36.1% at ten years. As those neighboring discs degenerate and lose height, the cumulative effect can gradually reduce stature years after the original surgery, though this is a slow process measured in millimeters.
What Determines Your Height Change
Several factors predict whether you’ll be taller or shorter after fusion:
- The condition being treated. Scoliosis and kyphosis corrections produce the largest gains because they’re literally unfolding a curved or hunched spine. Degenerative fusions at one or two levels produce little overall change.
- The number of levels fused. Longer constructs spanning many vertebrae have more potential to change height in either direction. A single-level lumbar fusion won’t noticeably alter your stature.
- Your preoperative curvature. Patients with larger curves have more height to “unlock.” A scoliosis curve of 70 degrees hides more vertical height than a curve of 40 degrees.
- Posture correction. A significant portion of measured height gain comes not from the spine itself getting longer, but from the entire body standing straighter. In the adult deformity study, improved alignment from the pelvis down to the ankles accounted for nearly half the total height gain.
What to Realistically Expect
If you’re having a one- or two-level fusion for a herniated disc or degenerative disease, your height will likely stay the same or change by a trivial amount. The surgery is designed to stabilize the spine and relieve pain, not to alter your stature.
If you’re having correction of a spinal deformity, whether scoliosis, kyphosis, or a combination, there’s a good chance you’ll be measurably taller. Three-quarters of adult deformity patients gain height, and for those with severe curves, the gain can be substantial. One important caveat for adolescents: while the correction itself adds height, the fused portion of the spine will no longer grow with you. In a growing child, this trade-off means the initial gain may be partially offset over the remaining growth years, though the net result is still typically positive.
Height measurements taken in the first days after surgery may not reflect your final result. The spine settles as swelling decreases and the fusion matures. Disc height at the fused level tends to decrease modestly over the first year before stabilizing, so a measurement at 12 months gives a more reliable picture than one taken in the recovery room.