Pseudarthrosis (Failed Spinal Fusion)

What it is

Pseudarthrosis — from the Greek for "false joint" — means a spinal fusion that never fully healed into one solid piece of bone. Instead of fusing, the operated segment keeps moving microscopically, which can keep producing pain long after the surgery itself has healed. It can occur at any level of the spine — cervical, thoracic, or lumbar — and after any type of fusion.

Symptoms

The most common pattern is pain that never really went away after fusion surgery, or pain that improved for a few months and then returned. Patients often describe a deep ache at the fused level, sometimes with a sense of instability or "giving way." When the nonunion allows motion that irritates nearby nerves, radiating arm or leg pain can develop as well. Because these symptoms overlap with other causes of persistent post-surgical pain, confirming the diagnosis requires careful imaging review.

Diagnosis

A CT scan is the key study for evaluating whether a fusion has healed — it shows the bony bridging (or lack of it) far better than plain X-rays. Flexion-extension X-rays can reveal excess motion at the fused segment, and loosening or breakage of screws or rods may be visible. Dr. Choi reviews your prior operative reports and imaging personally, because the details of the original surgery shape every decision about what comes next.

What your first visit covers

Your visit centers on two questions: has the fusion actually healed, and is the nonunion the true source of your pain? Dr. Choi correlates your symptoms with a fresh review of your imaging, examines you, and explains — in plain language — what the scans show and what your options are. If the fusion has healed and something else is driving your symptoms, he will tell you that too.

Treatment options

Not every pseudarthrosis needs surgery. If symptoms are mild and the hardware is stable, observation with activity modification and bone-health optimization is reasonable — and quitting nicotine is the single most important step you can take, since nicotine directly impairs bone healing. Bone growth stimulators (external devices worn over the fusion site) are sometimes used to encourage healing in select cases, though they cannot overcome ongoing nicotine use or mechanical instability.

When pain is significant and the nonunion is confirmed as the source, revision fusion surgery is the definitive treatment. The revision typically involves fresh bone graft — your own bone, donor bone, and/or biologic graft materials that stimulate bone growth — along with revised or extended hardware to provide the stability the first surgery lacked. The choice of graft and biologic is tailored to the reason the original fusion failed and to your individual healing capacity.

When a second opinion can help

Many patients with pseudarthrosis were told their fusion "looks fine" on X-ray — plain films miss nonunions that a CT would catch. Others were told nothing more can be done. A second opinion with fresh eyes on your imaging, your operative history, and your symptoms can change the plan entirely. Dr. Choi regularly evaluates patients whose prior fusions failed to heal and lays out what revision would — and would not — be expected to accomplish.

When to seek care promptly

Seek prompt evaluation if you develop new weakness, numbness in a limb, loss of bowel or bladder control, or sudden severe pain after fusion surgery — these can signal hardware failure, nerve injury, or infection rather than simple nonunion.

Frequently asked questions

What is pseudarthrosis after spinal fusion?

Pseudarthrosis means a spinal fusion failed to heal into solid bone. Instead of fusing into one continuous segment, the vertebrae keep moving slightly at the operated level, which can cause ongoing pain months or years after surgery.

How do you know if a spinal fusion didn't heal?

A CT scan is the most reliable way to check whether a fusion has healed, because it shows bony bridging in detail that plain X-rays can miss. Flexion-extension X-rays showing excess motion, or loose or broken hardware, also point toward nonunion.

What causes a spinal fusion to fail?

Smoking is the single most important preventable cause, since nicotine impairs bone healing. Other risk factors include diabetes, osteoporosis, poor nutrition, certain medications, multilevel fusions, and mechanical issues such as inadequate stability from the original construct.

Does pseudarthrosis always require surgery?

No. If symptoms are mild and the hardware remains stable, many patients do well with observation, activity modification, and optimizing bone health. Surgery is considered when pain is significant, function is limited, and the nonunion is confirmed as the pain source.

What does revision surgery for pseudarthrosis involve?

Revision surgery typically means re-fusing the segment with fresh bone graft and revised or extended hardware, while correcting whatever caused the first fusion to fail — whether biological, like poor bone healing, or mechanical, like inadequate stability.

Can I get a second opinion for a failed spinal fusion?

Yes. Dr. Choi regularly provides second opinions for patients whose fusions failed to heal, reviewing prior operative reports and imaging with fresh eyes. Many patients were told nothing more could be done, when a careful re-evaluation reveals treatable problems.

Pseudarthrosis (Nonunion After Spinal Fusion)