Disc replacement

Cervical and lumbar

Same principle, two very different operations. Read the two “who qualifies” rows against each other — that is where they part company.

Cervical disc replacement

Cervical arthroplasty — the common one

1:51 Play the 1:51 animation: Cervical disc replacement

What it is

Through the front of the neck, exactly as an ACDF is. The disc and any spur pressing on the nerve or cord are removed, and a two-piece device that articulates goes in where the disc was.

Who qualifies

Arm pain or cord compression from a disc at one or two levels, in a neck that still has reasonable alignment and facet joints that are not badly worn. A large share of people who need one- or two-level anterior cervical surgery are candidates.

Who it is not for

Significant facet arthritis at the level, instability or a slip, a neck that has lost its forward curve, poor bone quality, ossification of the ligament behind the disc, active infection, and pain that is mostly neck pain rather than arm or cord symptoms.

The procedure

Usually one to two hours per level. Often home the same day or after one night. No collar for most patients, and no bone graft to wait on.

Recovery

Generally quicker than an ACDF at the front end, because nothing has to fuse. Desk work commonly within one to two weeks and unrestricted activity over the following couple of months.

What the evidence shows

It has been compared against ACDF in randomised trials with follow-up now running well past ten years. The general direction is that results are at least as good as fusion for arm symptoms, with fewer people coming back for surgery at the neighbouring level.

Lumbar disc replacement

Lumbar arthroplasty — the exception

1:13 Play the 1:13 animation: Lumbar disc replacement

What it is

Through the front of the abdomen, past the great vessels, with the back muscles never crossed. The disc is removed and a device is set between the two vertebral bodies.

Who qualifies

Very few people, and that is the honest headline. Typically a single level, usually L4–5 or L5–S1, with disc pain confirmed as the source, intact facet joints, no slip and no instability, no significant canal narrowing, no previous posterior decompression at that level, and good bone quality. Most people who ask about this will not qualify, and a fusion is the operation that will help them.

Who it is not for

Any facet arthrosis worth the name, spondylolisthesis, stenosis needing a decompression from behind, more than one badly worn level, osteoporosis, significant deformity, or previous abdominal or vascular surgery that makes the front approach hazardous.

The procedure

Done with an access surgeon opening and closing the abdominal approach. Usually one or two nights in hospital.

Recovery

Walking the same day, with lifting and bending limited for the first several weeks. Because there is no fusion to protect, restrictions are about the anterior approach healing rather than about waiting on bone.

What the evidence shows

Randomised trials against anterior lumbar fusion have generally found it no worse in selected patients. The literature is smaller than the cervical literature, the selection criteria in those trials were strict, and revision is technically demanding because the front approach has to be repeated through scar.

Recovery and outcome figures on this page are general ranges from the surgical literature, not guarantees for any individual case. Whether either device is an option for you is decided on your own imaging — including standing X-rays and, for the low back, the state of the facet joints — and not on a preference stated at the first visit.

What it looks like on the X-ray

Drag the divider across each film to move between the pre-operative and post-operative image. Both panels are live; the radiographs themselves are still to come.

Any imaging shown here is from Dr. Zaidi’s own cases, used with the patient’s written permission and with all identifying information removed. One patient’s X-rays are not a prediction of anyone else’s result.

What an artificial disc is actually for

Not to avoid an operation — it is the same operation up to the point where the disc comes out. What it avoids is the consequence of fusing.

The problem it addresses

A fused level stops moving, and the movement it used to do is taken up by the levels above and below it. Over years that extra work can wear those neighbours faster than they would otherwise have worn — adjacent segment disease. It is not certain and it is not universal, but it is real, and it is the reason motion preservation exists.

What it does not change

The decompression. Getting the pressure off the nerve or the cord is the part that relieves the symptoms, and it is identical either way. A disc replacement is not a better decompression; it is a different thing done afterwards.

What it asks of you

Anatomy that can hold it. A device that moves needs the rest of the level to be capable of moving: joints at the back that are not worn out, alignment that is preserved, bone strong enough to hold the endplates, and no instability. Those requirements are what narrow the candidacy, and they narrow it far more in the low back than in the neck.

Where to go next

The index lists every procedure in one place; the approach page explains how the choice between a tube and an open exposure actually gets made, and the conditions list names what comes through the clinic most often.