Orthopedics · Part Four · Seeing and Ruling Out
Lesson 29 / 44
Findings in People Without Pain: What Spine Scans Show in People With No Symptoms
A disc bulge on a scan is one of the most common findings in people who feel completely fine. A spine image alone never settles the question of what is actually causing pain.
Disc bulges, disc degeneration, protrusions and annular fissures are common findings in people who have never had back pain. A systematic review of 33 studies and 3,110 asymptomatic individuals put disc degeneration at 37 percent of 20-year-olds and 96 percent of 80-year-olds. The finding is real and the pain is real, and the two are separately determined. The Unified Model of Tone reads the same structure meeting a different organization in each person.
Disc degeneration in pain-free people, ages 20 to 80
37 percent rising to 96 percent
Disc bulge in pain-free people, ages 20 to 80
30 percent rising to 84 percent
Spinal cord compression among 1,211 symptom-free necks
5.3 percent
Odds of a disc extrusion in adults 50 and under with back pain
4.38 times higher
What the words on the report mean
Radiology grades disc contour on a scale. A bulge is a symmetric extension beyond the edges of the vertebral bodies. A protrusion is focal or asymmetric, and an extrusion goes further still. An annular fissure is a break in the outer fibrous ring, and degeneration means loss of disc height and water.
Where a disc finding could hurt from
The outer third of the annulus, the posterior longitudinal ligament, the facet capsule and the sleeve around the nerve root all carry nociceptors. Chemical irritation from a torn annulus and sustained deformation of a root are the two routes that reliably generate symptoms. A contour change reaches those tissues in some people and not in others.
01Scans of people with no pain
A scan finding describes structure and does not identify the source of pain
An imaging finding describes structure, and structure is a weak guide to suffering. Scan adults who have no back pain at all and the reports come back full of the words that sound frightening on paper.
The cleanest demonstration was published in 1994. Ninety-eight people without back pain were scanned, and two neuroradiologists read the images blind. Twenty-seven scans from people who did have back pain were mixed in with them (Jensen 1994).
Thirty-six percent of the pain-free group had normal discs at every level. Fifty-two percent had a bulge at one level or more, 27 percent a protrusion and 1 percent an extrusion. Schmorl nodes reached 19 percent and annular defects 14 percent.
The authors drew the conclusion the numbers force. Given how common both the findings and back pain are, discovering a bulge in a person with low back pain may frequently be coincidental.
What the reports are actually describing
These are not errors in the machine. They are the normal texture of a spine that has done years of honest work. A structural change seen on a scan does not, by itself, prove that it is the source of a person’s pain. It is a candidate for the explanation, never the confession.
Conservative care begins from exactly this position of calm, and it treats the person in front of it rather than the label on a page.
02Findings
What the research shows
From two systematic reviews, a meta-analysis, five blinded prevalence studies and two prospective cohorts.
03The age-stratified table
Every common degenerative finding climbs with age in people who feel fine
The prevalence of degenerative findings in symptom-free people rises by the decade. Brinjikji and colleagues pooled 33 articles covering 3,110 asymptomatic individuals and fitted age-specific estimates by decade from 20 to 80 (Brinjikji 2015).
Disc degeneration ran from 37 percent at age 20 to 96 percent at age 80. Disc bulge ran from 30 percent to 84 percent. Disc protrusion ran from 29 percent to 43 percent. Annular fissure ran from 19 percent to 29 percent.
The four rows split into two pairs. Degeneration and bulge roughly triple and end up describing almost everyone. Protrusion and annular fissure move ten to fourteen points and stay a minority.
Earlier work set the pattern. Sixty-seven people who had never had low back pain or sciatica were read by three blinded neuroradiologists (Boden 1990). Roughly a third had a substantial abnormality. Degeneration or bulging appeared at one lumbar level or more in 35 percent of those aged 20 to 39, and in all but one aged 60 to 80.
Among 36 volunteers with no back pain and no sciatica, 81 percent had a bulging disc and 33 percent a focal protrusion. Twenty-eight annular tears turned up in 20 of them, and none had an extrusion (Stadnik 1998).
Beyond the low back
The neck behaves the same way. Among 1,211 healthy volunteers aged 20 to 70, 87.6 percent had disc bulging (Nakashima 2015). In their twenties it was already there in 73.3 percent of men and 78.0 percent of women.
A blinded 1990 series put cervical numbers beside the lumbar ones. A disc was degenerated or narrowed at one level or more in 25 percent of symptom-free volunteers under 40 and almost 60 percent over 40 (Boden 1990).
The knee tells the same story outside the spine. Among 5,397 knees in adults with no symptoms and no injury, cartilage defects ran at 11 percent under 40 and 43 percent at 40 and above (Culvenor 2019).
What the gradient describes
None of this describes damage in the way the word is usually meant. It describes maturation. A gray hair and a lined face are not injuries, and neither is a dehydrated disc at fifty. The spine adapts and keeps working.
When a report lists several of these features at once, an experienced clinician reads them as the expected background of a particular age, not as a catalog of things that have gone wrong.
04Findings that stay rare
Findings that are uncommon in pain-free people are the ones that carry information
The prevalence data cuts in two directions, and the second is usually left out. A finding that is nearly universal at a given age tells a clinician little. A rare finding tells them a great deal.
Sixty asymptomatic volunteers aged 20 to 50 were read by two musculoskeletal radiologists independently (Weishaupt 1998). Bulging or protrusion turned up in 62 and 67 percent of subjects, high-signal-intensity zones in 32 and 33 percent, and extrusions in 18 percent.
Then the numbers fall off a cliff. There were no disc sequestrations at all, and nerve root compression was diagnosed in a single intervertebral space by one reader. Endplate change appeared in 3 and 10 percent, and neither reader found severe facet osteoarthritis.
The neck splits the same way. Against disc bulging at 87.6 percent, cord compression sat at 5.3 percent and increased cord signal at 2.3 percent, both climbing after age 50 (Nakashima 2015).
Which findings carry weight
A meta-analysis put odds on each finding. Fourteen studies covering 3,097 adults aged 50 or younger, 1,193 of them asymptomatic, compared the two groups (Brinjikji 2015).
Six findings were more common in people with back pain. Disc bulge carried an odds ratio of 7.54, spondylolysis 5.06, disc extrusion 4.38, Modic type 1 change 4.01, protrusion 2.65 and degeneration 2.24. Five were not associated with pain, among them the high-intensity zone at 2.10 and annular fissure at 1.79, both with intervals crossing one.
The most disciplined comparison controlled for the confounder that wrecks the others. Forty-six patients whose sciatica required a discectomy were matched to 46 volunteers by age, sex and occupational risk (Boos 1995). Herniation appeared in 76 percent of the pain-free group and 96 percent of the patients.
Degeneration ran at 85 against 96 percent, a difference that did not reach significance. One variable separated the groups cleanly. Neural compromise was present in 83 percent of the patients and 22 percent of the matched controls. What the tissue does to the nerve carries the signal that contour does not.
05Followed for seven years
Findings present in pain-free people did not predict who later developed pain
Two prospective cohorts scanned people without pain and waited. Neither found the baseline findings predictive.
The 67 people scanned in 1989 were followed for seven years (Borenstein 2001). Twenty-one of them, 31 percent, had an identifiable abnormality of a disc or the spinal canal at baseline. Fifty returned the questionnaire and 31 were rescanned.
Twenty-nine of the 50 reported no back pain at all across those seven years. Low back pain developed in 21. Their 1989 scans had been normal in 12, showed a herniated disc in five, stenosis in three and moderate degeneration in one.
The people with the longest-lasting pain were not those with the greatest anatomic abnormality. A separate cohort of 148 outpatients aged 35 to 70 with no recent back pain was scanned twice, three years apart (Jarvik 2005).
Sixty-seven percent, 88 of 131, developed back pain. No association appeared between new pain and baseline endplate change, disc degeneration, annular tears or facet degeneration. The largest hazard ratio belonged to depression at 2.3. The Biopsychosocial Model sets out why a mood variable outperforms an anatomic one here.
Where structure did track symptoms
That study preserved the other half of the finding. New imaging findings were uncommon, the most frequent being disc signal loss in 11 subjects, 9 percent of those rescanned. Five developed a new disc extrusion and four new nerve root impingement.
All nine of them developed new pain. A structural change appearing in step with symptoms still counted, which is the pattern the rare-finding data predicts.
06Level, side and tissue
A finding earns its weight when the level, the side and the tissue match the symptoms
The finding only becomes meaningful when it fits the clinical picture, and establishing that fit is the real skill. This practice does not take these images in office. It refers out for high quality imaging when that is indicated, then interprets the study against the history and the examination.
The question is never simply what the scan shows. The question is whether the level, the side and the tissue on the image match the pattern of the person’s symptoms. A left sided bulge cannot explain right sided pain. A finding at one level cannot explain symptoms that follow a nerve from a different level.
When the anatomy and the story line up, the image earns its weight. When they do not, the finding is almost certainly incidental, one of the quiet features that populate nearly every adult spine. Where degeneration runs from 37 to 96 percent across the decades, incidental is the base rate (Brinjikji 2015).
Structure meets story
Imaging is a valuable tool for ruling out the rare, serious problem and for confirming a suspicion the examination has already raised. It is a poor tool for hunting through a healthy spine for something to blame. What MRI Is Really For sets out what a lumbar scan answers well.
Once it is clear how common these findings are in people who feel fine, a scary looking report stops being a diagnosis and becomes what it always was. It is information waiting to be matched against the person. The Clinicians Advantage follows that match.
07Why this is good news
Knowing how common these findings are removes a fear that costs people movement
Learning that bulges and degeneration are ordinary removes a heavy and unnecessary fear. Many people carry the belief that their spine is fragile or crumbling because a report used strong language, and that belief can quietly shrink a life. It discourages movement, feeds worry, and can shift the body into a protective, guarded state.
The prospective data supports that reframe rather than softening it. In the cohort scanned while pain-free and followed three years, the strongest predictor of new back pain was depression at a hazard ratio of 2.3 (Jarvik 2005). No structural finding matched it. Hurt Is Not Harm carries what follows for movement.
The far more accurate and encouraging truth is that a spine carrying a few age typical findings is usually a strong, adaptable, capable structure. Comfort and confident movement remain available. Reframing the report is not denial. It is a more faithful reading of what the evidence actually shows.
Conservative care leads with this understanding, and it is the smartest and safest starting point. It calms the fear a report can create, keeps people moving, and reserves the larger intervention for the uncommon situation that truly calls for it. A scan does not define a person. Conservative First places every intervention on one axis of magnitude.
08Claims removed from this page
Three figures from the earlier version were replaced with sourced data
The earlier text put disc bulges in roughly half of pain-free adults and protrusions in around a quarter. Both numbers are real, and both belong to one cohort of 98 adults scanned in 1994 (Jensen 1994).
Quoted without an age they hide the gradient that is the whole point, since bulge runs from 30 percent at 20 to 84 percent at 80. The line putting degeneration in the majority by the fourth decade came off for the same reason (Brinjikji 2015).
The earlier page also tied high intensity zones to annular fissures without a source. The pooled data counts them as separate findings with separate odds, and both now appear here with citations.
09The model on findings without pain
What the Unified Model of Tone claims about imaging findings in people with no symptoms
Everything above is established science, including the two cohorts in which the scans predicted nothing. What follows is our model’s reading, stated as ours rather than drawn from the papers.
Our model holds that subclinical dysfunction is not the absence of dysfunction. It is compensated tonal distortion, a distortion the system is still hiding. Reference ranges describe populations, and a person can sit comfortably inside one while having drifted far from their own functional baseline.
Both statements land on this data. A disc bulge at 84 percent prevalence sits inside the population range for an 80-year-old (Brinjikji 2015). That says nothing about whether that spine still regulates the way it used to.
Diagnosis marks a threshold rather than a beginning
Our model reads a diagnosis as the moment compensation became insufficient rather than the moment the process began. Twelve of the 21 who developed low back pain over seven years were read as normal in 1989 (Borenstein 2001).
The scan recorded structure. It did not record what those systems were spending to stay quiet, which is the variable our model says was moving.
The input law, applied to a disc
An input interacting with a tone creates an outcome. There is no such thing as an input acting upon an empty body. A herniated disc is an input to the tissue and the nerve around it, and the outcome depends on the organization it meets.
Boos and colleagues matched patients and controls for age, sex and occupational load, and still found herniation in 76 percent of the group with no symptoms (Boos 1995). The morphology was shared. The experience was not.
The prediction
From that follows a claim the imaging literature does not make. Our model predicts that two people with the same finding at the same level, one in pain and one not, differ measurably beforehand.
Four measures name the difference: pressure pain threshold recorded away from the imaged segment, active lumbar range of motion, resting heart rate variability, and time to return to baseline after a standardized load test. Our model further predicts that an input restoring regulation moves people who begin high and people who begin low toward the same middle.
This is a claim about how a structural finding is absorbed rather than a claim about what treatment does. If pressure pain threshold, active lumbar range of motion, resting heart rate variability and time to return to baseline after a load test are shown to move together, the unification claim is confirmed.
10The tone reading
How findings in people without pain express tone
Every topic in this library expresses all of tone. In imaging findings without symptoms three aspects carry the signature, because one disc contour appears in people with no pain and people with severe pain.
Set point
Reference ranges describe populations. A person sits comfortably inside the range for their age while having drifted far from the baseline their own system holds.
Time course
Findings accumulate by the decade. Disc bulge runs 30 percent at age 20 and 84 percent at age 80, so the film reports duration first.
Constraint
Compensation costs capacity. A guarded segment holds a narrow range, and the same annular fissure meets a wide one in the person who feels nothing.
The remaining foundations run through these findings too. Prediction: what a person expects a report to mean shapes how the body braces. Gain: an amplified system registers a common bulge as an emergency. Coupling: guarding recruits breathing and heart rate along with muscle. Load: the same degenerated disc is silent under one week of demand and sore under the next. Input quality: a segment that reports its position poorly gives the system less to work with. Oscillation: symptoms on a daily rhythm are reporting the regulator rather than the disc. These are readings of one organization rather than separate systems, which is the core claim of the Unified Model of Tone.
11Across the library
How this page relates to the rest of the library
The asymptomatic prevalence table is the base rate every other imaging lesson reads against.
What happens when a scan comes first, and how an incidental finding becomes a surgical plan.
How history and examination narrow the question before an image is worth ordering.
The questions a lumbar scan answers well, from neural compression to canal and foraminal dimensions.
Why the nervous system decides how much it hurts, with the emergency clinic data behind it.
The resorption rates and macrophage mechanism that shrink a herniation without an operation.
Disc composition, nutrition by diffusion, endplate anatomy and what a Modic change means.
Low back pain as a measurable regulatory state, and the instruments that read it.
12Frequently asked
Questions patients ask about scan findings without pain
Are disc bulges normal?
Very often, yes. In a systematic review pooling 33 studies of 3,110 people with no symptoms, disc bulge ran from 30 percent of 20-year-olds to 84 percent of 80-year-olds. In the neck the figure reaches 87.6 percent across 1,211 healthy volunteers, including 73.3 percent of men in their twenties. A bulge is a common feature of a working spine rather than an automatic cause of pain, so it has to be matched against the symptoms before it means anything.
Does everyone with a disc bulge have pain?
No. Among 98 adults with no back pain scanned and read blind, 52 percent had a bulge at one level or more and 27 percent had a protrusion. Only 36 percent had normal discs at every level. The authors concluded that finding a bulge or protrusion in a person with low back pain is frequently coincidental. The same structure produces pain in one person and nothing in another, which is why the level, the side and the tissue have to line up with the story.
Should scan findings scare me?
Usually not. Most of what appears on a spine report is an age typical change present in large numbers of people who feel completely well. Disc degeneration reaches 96 percent by age 80 in people with no pain. In a group scanned while pain-free and followed seven years, the baseline imaging did not predict who developed back pain or how long it lasted. Understanding the base rate lowers the fear and keeps people moving, which is what recovery runs on.
Which imaging findings actually matter?
The rare ones. Disc extrusion, sequestration, nerve root compression, endplate change and severe facet osteoarthritis were all uncommon among 60 asymptomatic volunteers under 50, which is what makes them informative when they do appear. In a meta-analysis of adults 50 and under, disc extrusion carried an odds ratio of 4.38 and spondylolysis 5.06 in people with back pain. A high-intensity zone sat at 2.10 with an interval crossing one, so on that evidence it carried no reliable signal at all.
If my scan shows degeneration, is my spine wearing out?
Degeneration on a report means loss of disc height and water content, and it accumulates in everyone. It ran from 37 percent of 20-year-olds to 96 percent of 80-year-olds among people with no symptoms at all. A gray hair and a lined face are not injuries, and neither is a dehydrated disc at fifty. In one matched comparison, degeneration appeared in 85 percent of pain-free volunteers and 96 percent of surgical patients, a difference that did not reach statistical significance.
Do scan findings predict whether someone will get back pain later?
The two cohorts that tested it directly found they did not. Of 50 people scanned while pain-free and followed seven years, 21 developed low back pain, and 12 of those had been read as normal at baseline. In a separate three-year cohort, no association appeared between new pain and baseline endplate change, degeneration, annular tears or facet degeneration. The largest hazard ratio in that model belonged to depression at 2.3, rather than to anything visible on the images.
What does the Unified Model of Tone say about findings in people without pain?
That a silent finding may be compensated rather than harmless, and imaging alone cannot tell which. Our model reads subclinical dysfunction as a distortion the system is still hiding, and reference ranges as population descriptions a person can sit inside while far from their own baseline. An input interacting with a tone creates the outcome, which is why herniation appeared in 76 percent of matched volunteers with no symptoms. The model predicts that pressure pain threshold, lumbar range of motion, heart rate variability and recovery time share one underlying factor, with compensation deciding how far each one moves.
13The sources
References
Twelve primary sources. Every figure quoted here was checked against the published abstract.
Related evidence