The claim, stated fairly
The case for a real difference isn't silly.
A basic traction setup pulls and holds. A decompression table like the DRX9000 runs a computer-controlled curve instead: tension rises, holds, eases and repeats, with the patient positioned so the force concentrates at one spinal level. The reasoning is that a steady pull makes spinal muscles brace, and braced muscles absorb the force before it reaches the disc.
Then there's the study every decompression brochure eventually cites. In 1994, Ramos and Martin put a cannula into the L4-5 disc space, connected it to a pressure transducer, laid the patient prone on a VAX-D table and raised the tension. Pressure inside the disc moved opposite to the tension, and at the upper range it dropped below -100 mm Hg.
Negative pressure inside a disc is a genuinely interesting finding. It's also where the argument usually stops, which is the problem.
What that pressure study does and doesn't show
Read the abstract closely and two things stand out.
The first: it measured pressure, not people. Nobody's pain score, walking distance or return to work appears in it. A disc can register negative pressure during a session and the person attached to it can feel exactly the same afterward.
The second is stranger. The abstract describes the method entirely in the singular — "a cannula inserted into the patient's L4-5 disc space" — and never states how many people were measured. For a paper quoted this often, across this many clinic websites, that's a thin foundation.
A mechanism is a hypothesis about why something might work. It isn't evidence that it does. Those two get blurred constantly in decompression marketing, ours included until we wrote this.
The FDA and the insurers put them in the same box
Regulators never adopted the distinction.
The FDA cleared the DRX9000 in 2006 as powered traction equipment, product code ITH. Not a decompression category. Traction.
Cigna goes further, and its policy is worth reading if you like watching a marketing claim meet an actuary. Coverage policy CPG 275, effective 4/15/2026, allows lumbar and cervical mechanical traction as medically necessary when clinical criteria are met, billed as CPT 97012. Then it calls nonsurgical axial/spinal decompression experimental, investigational and/or unproven, and specifies that this covers "any motorized mechanical traction device that is promoted as providing 'decompression therapy'" — listing the DRX-9000, Accu-SPINA, VAX-D and IDD Therapy by name. The per-session code, HCPCS S9090, sits in the experimental column.
So the same powered table can be a covered service or an unproven one depending on what the clinic calls it. Aetna and Medicare reach the same destination by a shorter road, as our page on Utah insurance coverage lays out.
Somebody actually tested the decompression version against a fake one
This is the study that settled the question for us, and we'd rather you heard about it here than from a competitor.
In 2009, Schimmel and colleagues in the Netherlands ran a single-blind randomized trial on 60 chronic low-back-pain patients. Every patient got standard graded-activity care and 20 sessions in an Accu-SPINA — a purpose-built decompression device, not a rope-and-pulley traction rig. Half got the real IDD protocol, with traction climbing to 50% of body weight plus 4.45 kg. Half got a sham: 4.45 kg, every session, which is barely more than the harness.
Both groups improved. Back pain on a 100-mm scale fell from 61 to 32 with the real protocol and from 53 to 36 with the sham, and leg pain, disability and quality of life improved in both.
The trial's own summary of the difference between the two: none of the parameters showed one. The authors concluded that adding this traction to a graded activity program "has been shown not to be effective".
That result doesn't say decompression is useless. It says the specific thing being sold — the calibrated pull — didn't add anything you couldn't get from a token pull plus a good exercise program.
And head to head against ordinary traction?
One small trial has done that comparison directly.
Choi, Lee and Hwangbo published it in 2015: 30 patients with chronic lumbar pain from disc herniation, split evenly, 15 on a spinal decompression device and 15 on a lumbar traction device, both alongside conservative physical therapy three times a week for four weeks.
Pain, disability and straight-leg raise improved in both groups. Between the groups, the authors found no statistically significant differences.
Thirty people is a small study and four weeks is a short one. Still, it's the direct comparison the "this isn't traction" argument needs, and it came back a draw.
So what should you do with all this?
Keep the mechanics and drop the marketing.
The cycling pull is real engineering, the negative pressure reading is real, and the older Cochrane work covering 32 trials looked at manual and mechanical traction alike — so nobody can claim decompression got left out of the evidence. It got included, and the better-designed the trial, the smaller the advantage.
What that changes in practice is the sales conversation, not the treatment. When a clinic's pitch leans on the word decompression, three questions sort it out fast:
- Which trial shows this table beating traction or sham?
- What happens to my plan if nothing has changed by the checkpoint?
- What does the whole thing cost, since insurers treat it as unproven?
Our answers, in order: none we know of, the plan gets reconsidered at treatments 8 to 12, and the price comes after the exam — see what decompression costs here.
Why Mecham Chiropractic still offers it
Fair question to end on.
Because "no better than sham in a 60-person trial" isn't the same as "helps nobody", and because the patients we're talking about have usually already tried rest, time and simpler care. A supervised trial of decompression, inside a plan with an exit, is a reasonable next step for a disc-driven problem — as long as nobody pretends the evidence is stronger than it is.
The protections matter more than the machine. An exam decides whether your pain behaves like a disc problem at all. A plan runs 20 to 30 sessions across 8 to 12 weeks, and if treatments 8 to 12 pass without meaningful improvement, it gets reconsidered instead of finished.
More on that in what to expect from spinal decompression and our full read of the research. Want to talk it through? Book an exam or phone (801) 590-8615.
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