01
The same approach
A short horizontal incision in a skin crease at the front of the neck, passing between the tissue planes rather than cutting muscle. The throat is moved gently aside in both.
ACDF or cervical disc replacement?
Both operations reach the same disc through the same small incision at the front of the neck, and both take the same pressure off the nerve or the cord. What differs is what goes into the space afterwards, and what that means over the years that follow. This is a comparison rather than a recommendation: which one suits is settled by your anatomy.
The short version
Up to the point the disc comes out, the two operations are the same.
A fusion locks the treated level. A disc replacement is designed to leave it moving.
In pooled trial data at seven years, 4.3 per cent of disc replacement patients had surgery at a neighbouring level against 10.8 per cent after fusion.
Disc replacement suits a specific anatomy. A worn, stiff, collapsed or unstable level is better fused.
Being turned down for an artificial disc is not bad news. It means the level would not support one.
Much of the trial evidence was funded by device manufacturers. That is normal for approval studies and worth knowing when reading it.
Same approach
Both operations go in from the front of the neck, through the same small incision.
4.3% vs 10.8%
Surgery at a neighbouring level within seven years, disc replacement against fusion.
1 to 3 days
Published hospital stay after disc replacement, against three to five days after a fusion.
Anatomy decides
Which operation suits you is settled by your imaging and your examination, not by preference.
WHAT IS SHARED
The same operation, up to a point
If you have read about ACDF you already know most of a disc replacement. The difference sits entirely in what happens after the disc is out.
02
The same decompression
The disc is removed along with any herniated material or bony spur pressing on the nerve root or the cord. This is the part that relieves your symptoms, and it is identical in both operations.
03
Different things go in
A fusion fills the space with a spacer, sometimes held with a small plate, and bone grows through it. A disc replacement seats a mobile artificial disc against prepared bone surfaces instead.
04
Different things afterwards
A fusion has to knit, which takes months and is affected by smoking. A disc replacement has nothing to wait for, but positioning matters more and the device has to keep moving.
SIDE BY SIDE
The comparison in full
Recovery figures are the practice's published guidance for each operation. The seven-year outcome figures come from a meta-analysis of eleven randomised trials, and describe groups of patients rather than individuals.
Compared on
ACDF
Cervical disc replacement
Approach
From the front of the neck
From the front of the neck
What fills the disc space
A spacer, sometimes with a small plate. Bone grows through it over months.
A mobile artificial disc, sized and seated against prepared bone surfaces.
Movement at that level
None. The level is fused deliberately.
Preserved, provided the device stays positioned and mobile.
Levels usually treated
One or two, sometimes more
Usually one or two
Published hospital stay
Approximately 3 to 5 days
Approximately 1 to 3 days
Driving and swimming
Driving restricted for about 4 to 6 weeks, swimming avoided for 4 to 6 weeks
Driving restricted for about 4 to 6 weeks, swimming avoided for 4 to 6 weeks
Does smoking matter
Considerably. It meaningfully reduces the chance of the fusion setting.
Less so, because nothing has to fuse, though it remains bad for healing generally.
Surgery at a neighbouring level, by 7 years
10.8 per cent
4.3 per cent
Further surgery at the treated level, by 7 years
12.7 per cent
5.2 per cent
Track record
The most established operation in cervical spine surgery.
Widely used, with trial follow-up extending to around seven years.
If it does not work out
Revision options are well established, including surgery at an adjacent level.
Can be converted to a fusion. A bigger operation, but a known fallback.
One row that is missing on purpose: how much either operation helps your arm pain. Both decompress the nerve in the same way, and for a compressed nerve root both are reliably effective. The choice between them is about the level itself, not about how well the pain settles.
PUBLISHED RESEARCH
What the seven-year data actually shows
This is one of the better-studied questions in spine surgery, because artificial discs had to be trialled directly against fusion in order to be approved. A meta-analysis pooled eleven randomised trials.
4.3% vs 10.8%
Surgery at a neighbouring level, by 7 years
Fusing a level places a little more demand on the levels above and below it. In the pooled data, 10.8 per cent of ACDF patients had surgery at an adjacent level within seven years, against 4.3 per cent after disc replacement. This is the main long-term argument for preserving motion.
Journal of Spine Surgery, 2020
5.2% vs 12.7%
Further surgery at the treated level, by 7 years
Reoperation at the level that was originally treated was also less common after disc replacement, at 5.2 per cent against 12.7 per cent. Both figures are worth putting alongside the fact that most people in both groups needed no further surgery at all.
Journal of Spine Surgery, 2020
How to read this
Many of the trials comparing artificial discs with fusion were funded by device manufacturers. That is normal for approval studies, and it does not make the results wrong, but it is worth knowing when reading strongly positive findings. The figures above come from a pooled analysis of randomised trials rather than a single study, which is the more reliable form of that evidence.
These are also averages across trial populations who were selected as suitable for either operation. If your own level is worn, stiff or unstable, the disc replacement arm of those trials does not describe you.
WHO SUITS WHICH
The level decides more than the preference does
Disc replacement performs well in the right neck and poorly in the wrong one. These are the features that push the decision one way or the other.
Disc replacement is worth considering when
The compression is at one or two levels and comes from a disc rather than extensive bony change.
The disc height is largely preserved and the level still moves on flexion and extension views.
The facet joints are in reasonable condition and the alignment of the neck is normal.
Bone quality is adequate, and you are young enough that the levels above and below have a long working life ahead of them.
A fusion is the better operation when
The level is already stiff, collapsed or severely worn, so there is little motion left to preserve.
There is instability at the level, or the alignment of the neck is abnormal.
The facet joints are arthritic, or the compression comes mostly from bone rather than disc.
Bone quality is poor, or several levels need treating at once.
If a fusion has been recommended, the useful question is which of these applied to you. It should be a clear and specific answer. About ACDF and about disc replacement go through each operation in detail.
MOTION
Does preserving movement actually matter?
You will not feel the difference day to day
A single fused level takes a small amount of movement out of a neck that has seven, and the remaining levels compensate. Most people do not notice a functional difference after a one-level fusion, and preserved motion is not something you experience directly. The argument for it is about the years afterwards rather than the months.
About ACDF ›The case for it is what happens next door
A fused level places slightly more demand on its neighbours, and the seven-year data reflects that. Preserving motion is a bet on reducing that demand over decades. It is a reasonable bet in the right neck, and a poor one in a level that is already stiff, where a device would not move much anyway.
About disc replacement ›The level decides this, not the preference
Both operations reach the same disc through the same incision and take the same pressure off the nerve. What separates them is whether the level you have can support a mobile device: disc height, alignment, the condition of the facet joints and bone quality. A recommendation either way should name which of those applied to you.
RECOVERY
Where recovery differs, and where it does not
The published guidance is largely the same for both. The one clear difference is how long you are in hospital.
IN HOSPITAL
The one real difference
The practice publishes a stay of approximately three to five days after a fusion and one to three days after a disc replacement. A physiotherapist assesses your recovery before you go home in both cases.
AT HOME
Identical wound care
The incision is the same, so the instructions are the same: keep it clean and dry, adapt bathing or cover it as instructed, and avoid touching it.
4 TO 6 WEEKS
The same restrictions
Driving is restricted for approximately four to six weeks after either operation, and swimming is avoided for four to six weeks. Heavy lifting is avoided during the initial recovery period.
LONGER TERM
A fusion has to set
Bone growth across a fused level continues for months after you feel well, which is why smoking matters so much after an ACDF. A disc replacement has nothing to knit, but lifting, bending and twisting may still be restricted while you recover.
Both sets of figures are the practice's published guidance rather than a commitment about your own recovery. Recovery after cervical spine surgery covers what happens before, during and after an admission.
COMMON QUESTIONS
What people ask when choosing
Is disc replacement simply better?
Better for the right patient, not better in general. At seven years it shows lower rates of further surgery, but only in people whose anatomy suits it. In a stiff, collapsed or unstable level a fusion is the better operation, and it is not a consolation prize.
Why was I offered a fusion?
Usually because something about the level rules out an artificial disc: it is too worn or stiff, the alignment is off, the facet joints are arthritic, or the bone quality is not adequate. Ask specifically which of those applies to you. It should be a clear answer.
How long does an artificial disc last?
Trial follow-up extends to around seven years with most devices performing well. Beyond that the data thins out, because these implants have not been in use long enough. That uncertainty is a genuine consideration for a younger patient.
Can I have both, at different levels?
Hybrid constructs, fusing one level and replacing another, are used where the two levels differ in condition. Whether that applies depends entirely on what each individual level looks like on your imaging.
Which has the shorter recovery?
On the published guidance, the hospital stay is shorter after a disc replacement. The driving, swimming and lifting restrictions are the same for both, so the difference in day-to-day recovery is smaller than people often expect.
Does it matter that the trials were industry funded?
It is worth knowing rather than disqualifying. Approval studies are almost always manufacturer funded. The stronger evidence is the pooled analysis of eleven randomised trials rather than any single positive study, and the direction of the adjacent-level finding has been consistent.
NEXT
Where to go from here
ACDF
What the operation involves, who it suits, the risks with figures where good data exists, and what recovery looks like.
About ACDF ›Cervical disc replacement
The same approach with a mobile artificial disc instead of a fusion, and what the seven-year evidence supports.
About disc replacement ›Do I need neck surgery?
What has to be true before an operation belongs in the conversation, and what can safely be watched instead.
Work through it ›About this information
This page is general information comparing two procedures and is not advice about your own case. The seven-year outcome figures come from the pooled analysis listed below and describe groups of patients rather than individuals. The recovery figures are the practice's published guidance for each operation, not a commitment about your own recovery. More about Dr Tollesson.
References
Cervical disc arthroplasty versus anterior cervical discectomy and fusion: a meta-analysis of rates of adjacent-level surgery to 7-year follow-up. Journal of Spine Surgery, 2020, pooling 11 randomised controlled trials, for the adjacent-level and index-level reoperation rates quoted above.
Surgeon Procedure Volume and Complication Rates in Anterior Cervical Discectomy and Fusions. Clinical Spine Surgery, 2017, for anterior approach complication rates.
Which operation your level supports is answered by your imaging, not by preference.
Which operation your level supports is answered by looking at your imaging and your examination, not by preference. A consultation will set out the honest alternatives. A GP or specialist referral is needed for a Medicare rebate.