Problems After Spinal Fusion

Many of these are found on X-rays and need no surgery. Others cause pain or posture changes and need a revision.

Adjacent segment disease

A fused section no longer moves, so nearby levels take on more stress. Each year, about 0.6–3.9% of fusion patients develop symptoms from the level next door. Over 10 years, about 10% need another operation for it. After a one-level fusion for spondylolisthesis, symptomatic adjacent disease reached 6% at 2 years, 14% at 5 years, and 31% at 10 years.

Proximal junctional kyphosis (PJK) and failure (PJF)

PJK is an increased forward bend at the top of a long fusion. In a large multicenter database, it appeared on X-rays in about 48% of patients within two years. Many of those patients had no symptoms.

PJF is the more serious form. It involves a fracture, loosening screws, or ligament failure, and it occurred in about 13% of patients. About one-third of patients with PJF had a revision within two years. PJF tends to happen early, often within the first few months.

Risk factors include older age, osteoporosis, a very large correction, and correcting beyond age-appropriate alignment goals. A 2026 study found that PJK takes several forms. The most common was degeneration of the disc just above the fusion. Screw loosening and fractures were the forms most likely to need reoperation.

Broken rods

Rods can break when the bone has not fully fused and the metal is repeatedly stressed. In one long-term study of fusions to the pelvis, about 39% of patients had a rod fracture within about five years. Nearly three-quarters of those fractures occurred more than two years after surgery.

Whether a broken rod needs treatment depends on the type of break:

• A single, non-displaced break often needs no surgery.
• Breaks in both rods with loss of correction usually do. In one study, 88% of these were revised, compared with 5% of single breaks.

Using extra rods across high-stress areas lowers the risk.

Fusion that doesn't heal (pseudarthrosis)

Non-healing occurs in about 4–24% of long deformity fusions. It is often what lies behind a broken rod.

Warning signs to report

• New or worsening pain at the top or bottom of the fusion
• Increasing forward lean, or a new bump at the top of the fusion
• A "pop" followed by new pain
• New leg weakness or numbness (report urgently)

What does revision surgery involve?

Revision surgery may extend the fusion, repair a non-healed area, replace broken rods, or realign the spine. Revisions are a large share of deformity care. In a 2024 study by Dr. Diebo's group, 45% of adult deformity operations were revisions.

How can these problems be prevented?

• Check and treat bone health before surgery
• Plan alignment to each patient's pelvic shape and age
• Choose the top and bottom levels of the fusion carefully
• Use supplemental rods where stress is high

When to see a specialist. If you have new pain, posture change, or a broken rod after fusion, request a revision evaluation.

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