The Adjacent Segment Trap: Why Spinal Fusion Fails

You have been told a spinal fusion is your last resort — that one segment of your spine is the problem, and that welding it together will finally give you relief.

Before you consent to an irreversible operation, you deserve to understand what fusion actually does to the rest of your spine. Not to the segment being fused. To the segments that are currently fine.

Your spine handles force by moving

Nature built your spine to dissipate force through motion. That is the design. Load arrives, and it is distributed across many segments, each one absorbing a share by moving slightly. No single level carries the whole burden, because no single level was built to.

That shared arrangement is the reason a healthy spine tolerates decades of loading without failing.

What happens when you remove one segment from the system

Fuse two vertebrae and you eliminate motion at that segment. That is the intended effect — the painful level stops moving, and the pain generated by that motion stops with it.

But the force does not vanish. Force is conserved. It has to be absorbed somewhere, and with one segment no longer participating, it lands on the segments immediately above and below.

Those neighbors now carry a larger share than they were designed for. Intradiscal pressure rises. Kinematic stress increases. And they do so on discs that were, until the moment of your surgery, healthy.

This is not a theory about what might happen. It is what necessarily happens when you remove a load-sharing element from a load-sharing system.

The domino effect

The result follows predictably. The fused level is fixed. The neighbors begin to degenerate.

According to seminal research published in The Journal of Bone and Joint Surgery by Hilibrand et al. (1999), the incidence of symptomatic adjacent segment degeneration following cervical arthrodesis is significant. That framing deserves emphasis: it is a documented biological consequence, not a rare complication. It is not filed under “unfortunate outcomes.” It is what the operation does.

So the patient comes back. Another level is now symptomatic. Another fusion is recommended, which eliminates another load-sharing segment, which transfers the force again — to the next healthy disc in line.

Another domino.

This is how a person becomes a permanent surgical customer. Not through anyone’s ill intent, and not because any individual surgeon did anything wrong. Each operation, considered on its own, is a reasonable response to the problem in front of it. It is the sequence that traps you, and the sequence is nobody’s job to evaluate.

The alternative: treat the terrain and the tissue

The honest counter-question is: if not fusion, then what?

The alternative is motion-preserving and biologically driven. Rather than welding the structure, it addresses the terrain and the tissue.

The tissue is what actually failed. A degenerating segment is not simply mispositioned — it is biologically compromised. Treating it means supporting the structures around it rather than eliminating their movement.

The terrain is the metabolic and inflammatory environment that tissue lives in. Repair is something your body performs, and it performs it according to the conditions available. A body in metabolic disarray cannot execute a repair instruction no matter how precisely that instruction is delivered.

And motion preservation matters for a specific mechanical reason that follows directly from everything above: a segment that still moves is still sharing load. Preserving motion at the painful level keeps its neighbors from absorbing what it used to.

Fusion is sometimes genuinely necessary

That has to be said plainly, because the point here is not that fusion is always wrong.

There are spines with instability, deformity, or neurological compromise where fusion is the correct operation and where delay causes harm. Surgeons who recommend it in those situations are recommending the right thing.

The argument is narrower and more important than “avoid surgery.” It is that fusion should be an informed decision, not a default. You are entitled to know that the operation transfers load to your healthy levels, that adjacent segment degeneration is a documented consequence rather than a rare accident, and that a motion-preserving path exists and can be evaluated first.

If you fuse and it does not work, the preservation option is gone. If you attempt preservation and it does not work, fusion is still there. The order of operations is not symmetric, and that asymmetry should inform your sequence.

Which path applies to your spine is a clinical question requiring imaging, examination, and metabolic assessment — the purpose of a formal evaluation.

Frequently asked questions

Key takeaways

• Your spine dissipates force through motion, with every segment sharing the load.
• Fusing two vertebrae eliminates motion at that level, and the force transfers to the segments above and below, raising intradiscal pressure and kinematic stress on previously healthy discs.
• Hilibrand et al. (1999), in The Journal of Bone and Joint Surgery, documented that symptomatic adjacent segment degeneration after cervical arthrodesis is significant — a biological consequence, not a rare complication.
• The domino effect drives repeat surgery: each fusion transfers load to the next healthy level.
• Fusion is sometimes genuinely necessary, but it should be an informed decision rather than a default, and a motion-preserving biological path deserves evaluation first.

Studies referenced

• Hilibrand et al. (1999). The Journal of Bone and Joint Surgery — incidence of symptomatic adjacent segment degeneration following cervical arthrodesis.

Medically reviewed by Gurpreet Singh Padda, MD, MBA, MHP — Board Certified in Anesthesiology, Pain Medicine, Interventional Pain Management, Addiction Medicine, and Obesity Medicine. Last reviewed July 2026.

This article is educational and is not a substitute for evaluation, diagnosis, or treatment by a physician. Individual results vary, and not every patient is a candidate for the therapies described. Do not start, stop, or change any treatment without consulting your physician. Orthobiologic therapies are not FDA-approved for this indication and are provided as part of physician-directed care.