How does spinal fusion work?

The surgeon reaches the affected part of the spine, removes tissue that prevents the bones from contacting properly, and prepares the surfaces for healing. Bone graft or a bone graft substitute is placed in the space between vertebrae. A PEEK spinal cage may support the disc space, while pedicle screws and connecting rods hold the segments in alignment. Over time, the treated vertebrae heal together as one less-mobile section.

Fusion can reduce movement at a painful or unstable segment, but it does not replace every source of back or leg symptoms. The level treated, surgical approach and need for decompression depend on the diagnosis, such as spinal stenosis, spondylolisthesis or spondylolysis.

Your team may review medicines, nicotine use, bone health and home support before surgery. Afterward, follow wound and lifting instructions, change position regularly, and walk as advised. Rehabilitation builds mobility, posture, leg strength and safe body mechanics in stages. Do not add exercises or lifting because pain has improved; the fusion still needs time to mature. Read about [Post-Operative Rehabilitation](/treatments/physiotherapy-and-rehabilitation/post-operative-rehabilitation/), [Bone Graft Substitute](/materials/bone-graft-substitute/) and [Pedicle Screw](/materials/pedicle-screw/).

Seek urgent medical advice for new or worsening leg weakness, loss of bladder or bowel control, numbness around the inner thighs, severe unrelenting pain, fever, wound drainage, chest pain or breathlessness. A fall, wound opening or sudden change in walking also deserves prompt assessment.

Ask which spinal level will be fused, whether decompression is also needed, what hardware or cage is planned, how bone healing will be checked, and when work, driving and lifting may resume.