Am I a Candidate for Disc Replacement?

Name: Am I a Candidate for Disc Replacement?
Creator: Ryan Sauber, MD

Reviewed by Ryan Sauber, MD · Fellowship Director, AHN Orthopaedic Spine Fellowship · Last reviewed June 2026

Candidacy for disc replacement is determined by a specific set of anatomic, clinical, and documentation criteria. Meeting them is the difference between a procedure that addresses the pain and a procedure that does not. This page covers the criteria, why each one matters, what an evaluation involves, and the typical reasons that a patient who expects to be a candidate turns out not to be.

This is the page worth reading slowly. The candidacy question is the most important conversation a patient considering disc replacement can have, and the criteria below are not negotiable.

The hard requirements

Seven criteria are the floor. Each one has to be met before disc replacement is on the table.

Single- or two-level lumbar disc disease, confirmed on current imaging

Three or more levels of degenerative disc disease change the calculus. The procedure becomes more involved, multiple devices have to integrate cleanly, and the long-term reliability declines. Disc replacement is an option for one or two levels, not for the whole lumbar spine. Patients with widespread multilevel disease are better served by a different conversation.

Intact facet joints at the operative level

The facet joints at the back of each spinal segment are themselves a common source of low back pain. If the facet joints at the level being considered are significantly arthritic, replacing the disc does not address that pain — and may even make it worse by changing the loading at the facet. Imaging that shows significant facet arthritis at the level being considered is a contraindication.

No instability at the operative level

Disc replacement preserves motion. If the segment is already moving inappropriately — spondylolisthesis (a slipped vertebra), spondylolysis (a defect in the bony arch), or abnormal segmental motion on dynamic imaging — preserving more motion is exactly the wrong move. Instability requires stabilization, not motion preservation. Patients with instability at the operative level are not candidates for disc replacement at that level.

Adequate bone quality

The artificial disc has to integrate securely with the bone above and below it. Significant osteoporosis below specific thresholds means the bone may not hold the implant reliably over time. Bone density is assessed before any decision is finalized, and patients with osteoporosis below the acceptable threshold are not candidates until that is addressed.

BMI within accepted ranges

Higher BMI is associated with both more technical difficulty during the anterior approach and higher rates of device-related complications over time. The FDA-approved indications include specific BMI thresholds. Patients above those thresholds may still have surgical options, but disc replacement is not one of them at that point.

A real prior course of conservative care

Disc replacement is not a first-line treatment. A meaningful prior course of conservative care — structured physical therapy, anti-inflammatories, sometimes injections, and activity modification — is required before surgery is appropriate, both clinically and for insurance approval. A real prior course means six weeks or more of formal therapy, completed and documented; not a single visit or an informal home program.

A pain pattern consistent with discogenic pain

The pain pattern needs to match what disc-mediated pain typically looks like: axial low back pain that is reproducible with movement, loading, or prolonged positions; often worsened by sitting; sometimes with referred discomfort into the buttocks or thighs. If the pain pattern looks more like radiculopathy, claudication, or facet- or sacroiliac-joint pain, the disc may not be the actual pain generator — and replacing it will not help.

The clinical judgment factors

Meeting the seven hard criteria is the floor, not the ceiling. The decision to recommend disc replacement is built on a wider picture. Things that influence the final recommendation, even when the hard criteria are met:

How long the pain has been present, and how it has changed over that time.
What imaging shows beyond the basic findings — Modic changes at the endplate, the disc desiccation pattern, the appearance of adjacent segments, the rest of the lumbar facet arthropathy picture.
Prior spine surgery history. Some prior procedures change the anatomy in ways that complicate the anterior approach or the device positioning.
Activity level and functional goals. The expectations and demands a patient brings to the conversation matter.
Other medical conditions that influence anesthesia, healing, or the anterior abdominal exposure.
The pattern of what conservative care has actually shown. Sometimes the conservative care story itself reveals more about the pain generator than the imaging does.

What disqualifies a patient

Common reasons a patient is not a candidate, even when they expect to be:

The disc is not the actual pain generator. Most often the pain is facet-mediated, from the sacroiliac joint, or from spinal stenosis at a different level.
Instability is present at the operative level. Disc replacement is not the right answer for instability; stabilization is.
Significant facet arthritis at the operative level.
Three or more levels of degenerative disc disease.
Osteoporosis below the threshold required for reliable implant fixation.
BMI above the FDA-approved range.
Certain prior spine procedures that change the anterior anatomy.
Active infection or recent infection at the operative site.
The pain pattern, exam findings, and imaging do not converge on the disc as the source.

None of these are failures. They are reasons to choose a different right answer. For most patients in these categories, there is still a good path forward — it is just not this specific procedure.

What insurance approval requires

Insurance documentation is its own set of criteria, separate from the clinical ones. In recent experience, coverage for appropriate candidates has been good. The documentation required is consistent across major payers and the timing matters.

Six weeks of formal physical therapy completed within the last six months. The recency requirement is the most common reason approvals are delayed. Physical therapy from a year or two ago does not count, even if it was diligent at the time.
A current MRI of the lumbar spine within the last six months.
A current CT scan of the lumbar spine within the last six months.
Documented chronic low back pain despite conservative care. A real, continuing pain story documented in the medical record.
A course of epidural injections or other procedural conservative care is sometimes required.
A psychiatric evaluation is occasionally required.

The practical pattern that gets patients approved efficiently: make sure the imaging is current and that a recent formal course of physical therapy is on the record before pursuing approval. Anything older than six months will need to be repeated.

What an evaluation actually involves

An evaluation for disc replacement candidacy is not a single appointment with a yes or no answer. It is a process. What it typically includes:

A detailed history covering the pain pattern, what makes it better and worse, prior treatments and their effect, and the trajectory over time.
A focused physical exam looking at the lumbar spine, the surrounding joints, and neurological function.
Review of current MRI and CT imaging. Older studies often need to be repeated for both clinical and approval purposes.
Dynamic flexion-extension X-rays to assess for segmental instability that may not be apparent on still imaging.
Targeted diagnostic injections in some cases — to confirm or rule out the disc, the facets, or the sacroiliac joint as the actual pain source.
A real conversation about what the imaging shows, what it does not show, the realistic options, and what each one asks of the patient.

The work of an evaluation is to figure out which kind of patient you are. The conclusion sometimes is “you are a good candidate for disc replacement,” and sometimes is “you are a candidate for something else,” and sometimes is “non-surgical care is still the right answer for now.” All three are legitimate outcomes of a careful evaluation.

If you have been told you are not a candidate elsewhere, or if you have been told you need a fusion and want a second opinion before committing to one, that is also a real and reasonable conversation. The criteria above are specific, and they require a careful look at current imaging and history. A second opinion that does that work is rarely wasted.

More on disc replacement and motion preservation → · More on the lumbar procedure specifically → · How fusion-versus-replacement decisions actually work →

Common questions about candidacy

Am I too old for disc replacement?

Age itself is not a hard exclusion. What matters is bone quality, the rest of the lumbar spine, the pain pattern, and overall health. Patients in their sixties and seventies with intact facets, good bone density, and a discogenic pain pattern can be candidates. Patients of any age with significant facet arthritis, osteoporosis, or multilevel disease may not be. The decision is anatomic and physiologic, not chronological.

Is two-level disc disease still a candidate situation?

Yes. Disc replacement is an option for single- or two-level lumbar disc disease, provided the other hard criteria are met at both levels. Two-level cases are technically more involved, but they are within the approved indications and within my practice. Three or more levels of degenerative disc disease is a different conversation.

What if I have spondylolisthesis?

Spondylolisthesis at the operative level is a contraindication to disc replacement at that level. The reason is mechanical — disc replacement preserves motion, and if the segment is already moving inappropriately, preserving more motion is the wrong direction. Patients with spondylolisthesis who require surgery are typically candidates for a fusion of the affected segment, not a disc replacement. A spondylolisthesis at a different level than the operative level is a more nuanced conversation.

What if I have osteoporosis?

Significant osteoporosis below specific thresholds is a contraindication, because the artificial disc needs solid bone to integrate with above and below. Mild bone density loss can sometimes be addressed before surgery and the candidacy question reconsidered. Bone density is assessed before any final decision.

Do I really have to do six weeks of physical therapy first?

Yes, and the timing matters. Insurance approval for disc replacement requires six weeks of formal physical therapy completed within the last six months. Older physical therapy, even if diligent and well-documented, will not count. The clinical reason mirrors the insurance reason: many patients who think they need surgery improve substantially with a real, structured course of physical therapy first. The conservative care step is not a hurdle to clear — it is part of the diagnostic process.

What if I had spine surgery before?

Depends on the prior surgery. A prior microdiscectomy at a different level usually does not change candidacy at the level being considered. A prior fusion at an adjacent level can change the calculus — sometimes by making disc replacement more appropriate at the next level, sometimes by changing the anatomy enough that the anterior approach is more complicated. A prior spine surgery is not an automatic disqualification, but it is a specific conversation to have with the records in front of us.

What if I am not a candidate?

Not being a candidate for disc replacement is not the same as having no options. The most common reasons a patient is not a candidate — the disc is not the pain generator, facet arthritis or instability is present, or multilevel disease — each have their own appropriate treatments. Sometimes the right answer is a targeted decompression. Sometimes it is non-surgical care that continues to be refined. For patients with instability that requires stabilization, a fusion is sometimes the right answer. The work of an evaluation is to find that right answer, whatever it is.