Screws loosen and rods break. That is a failure rate, not a scandal.

POSTERIOR HARDWARE FAILURE

Screws loosen. Rods break. Constructs pull out of bone that was never going to hold them. None of that is malpractice — it is the failure rate of metal fixed to a moving skeleton, and it is worth knowing the numbers before you are told yours is unusual.

What posterior instrumentation is doing

A posterior cervical construct — typically lateral mass screws at C3 to C6, pedicle or pars screws at C2 and C7, joined by rods — is a temporary internal splint. Its job is to hold alignment while bone fuses. The metal is not the long-term solution; the fusion is. If the bone does not knit, the metal is being asked to carry load indefinitely, and metal loses that argument eventually.

That is why hardware failure and pseudarthrosis are usually the same story told from two ends. Screws rarely break in a solidly fused construct.

What actually fails, and roughly how often

Reported instrumentation failure rates after laminectomy and posterior cervical fusion vary widely with construct length, where it stops, and the patient. What the literature agrees on is the risk factors rather than a single number.

• Constructs crossing the cervicothoracic junction — the transition from mobile cervical spine to rigid thorax concentrates stress, and distal junctional problems are over-represented there.
• Long constructs and multi-level fusions, where more levels means more interfaces to fail.
• Poor bone quality — osteoporosis is the most common reason a screw does not hold what it was asked to hold.
• Failure to achieve fusion, for the reason above.
• Sagittal alignment that was not corrected, leaving the construct fighting the position of the head.

Lateral mass screw fixation itself has a long safety record in systematic review — the technique is not the fragile part. The fragile part is biology and alignment.

How you would know

New pain months or years after a settled recovery is the usual story, often positional and often described as a click, a shift or a grinding. Sometimes a screw becomes prominent enough to feel. Sometimes there are no symptoms and it is found on a film taken for another reason.

Broken hardware in a solidly fused spine is frequently left alone. Broken hardware together with a pseudarthrosis is a different conversation, and it is one worth entering with the pain generator already identified — because a confirmed facet source above a solid construct and a genuine nonunion look similar on a report and lead to very different operations.

What we do and do not do about it

This is not a surgical practice, and hardware revision is not something we offer. What we do is answer the question that usually has not been answered: is the hardware the reason you hurt, or is it an incidental finding next to a pain generator nobody has tested?

Those are very different situations and they look identical on a report. A facet joint above a construct can generate a great deal of pain while the metal below it is doing exactly what it should. That is testable with a block, and it is worth testing before anybody discusses revision surgery.

The honest limits of this page

We cannot tell you your specific failure rate. It depends on your construct, your bone, your alignment and your surgeon, and anybody quoting you a single percentage for “posterior cervical fusion” is flattening a large amount of variation.

What we can tell you is that failure is a known and studied outcome rather than an anomaly, that it is usually downstream of the fusion not taking, and that having it does not mean something went wrong in the operating room.

What imaging is worth doing

Plain flexion-extension radiographs first, because motion across a segment that should be fused is the finding that matters and it is invisible on a static scan. CT is the standard for assessing whether the fusion mass is actually solid; MRI is degraded by metal artefact and answers a different question.

An MRI ordered to investigate suspected hardware failure frequently produces an unreadable region next to the hardware and a list of degenerative findings elsewhere, which then get treated. That is worth avoiding.

The incentive worth naming

Revision spine surgery is well reimbursed and the decision to do it rests on findings that are genuinely open to interpretation. That is not an accusation of anybody; it is a structural fact about how the decision gets made, and it is a reason to have the pain generator identified independently before a revision is discussed.

A confirmed facet source above a solid construct is a completely different conversation from a pseudarthrosis, and the two look similar on a report.

Questions worth asking before agreeing to a revision

• Is the fusion solid? If it is, broken hardware is frequently left alone.
• What exactly is expected to improve, and by how much? “Stabilize the construct” is not a symptom.
• Has the pain generator been identified independently of the imaging? A facet source above a solid fusion is a different problem with a smaller solution.
• What happens if nothing is done? Sometimes the honest answer is very little.

None of those are hostile questions and a good surgeon will welcome all four.

Bone quality is the variable nobody measured

The most common reason a screw does not hold is that the bone it was asked to hold in was never assessed. Osteoporosis and osteopenia are routine in the age group having these operations and are frequently unmeasured before instrumentation goes in.

That is worth knowing afterward as well as before. If your construct has loosened, a bone density scan and a proper look at vitamin D, calcium and the metabolic picture is a reasonable thing to ask for — both to explain what happened and to change what happens to the next construct if there is one.

What people ask about failed hardware

Does broken hardware always need removing?

No. A broken screw in a solidly fused spine is often left in place and causes no problem. Removal is considered when the hardware is symptomatic, prominent, infected, or associated with a pseudarthrosis. Still in pain after a fusion. A finding on imaging is not on its own an indication to operate.

Can hardware set off airport detectors?

Occasionally. It is worth carrying documentation, but it is a nuisance rather than a clinical issue. How facet pain is confirmed.

My screws look loose on the X-ray. Is that why I hurt?

Possibly, and possibly not. A halo around a screw is a finding, not a diagnosis, and it sits next to other structures that have never been tested. Establishing which one generates your pain is the useful next step. Losing rotation after a fusion.

Should I see my original surgeon?

For anything structural, yes — they know the construct. For axial pain that has never been worked up, a diagnostic assessment first usually saves everybody time. Still in pain after a fusion.

Related reading

• When the fusion did not fix it
• Losing neck rotation after fusion
• Diagnostic medial branch block
• Sleep after neck surgery
• When a neck problem is urgent
• Vestibular testing