Discopathy – What Will an MRI Show?
Discopathy—a condition affecting the intervertebral discs—affects 60–80% of Poles at least once in their lives. Magnetic resonance imaging (MRI) of the spine is the gold standard in diagnosis – it shows the condition of the discs, nerve roots, muscles, and spinal canal with a level of accuracy impossible to achieve with other tests. I will explain exactly what a radiologist looks at in an MRI of the lumbar spine (the most common site of disc herniation) and how to interpret the results.
In this article
Anatomy of the disc and types of changes
The intervertebral disc has a nucleus pulposus (a gel-like structure in the center) surrounded by an annulus fibrosus (a hard, fibrous outer layer). Changes on MRI are described as: dehydration (loss of water in the nucleus, “black disc”); protrusion (bulging, the nucleus does not rupture the annulus); extrusion/herniation (the nucleus ruptures the annulus); sequestration (a piece of the nucleus is free in the spinal canal). Each type requires a different treatment approach.
What do “L4-L5” and “L5-S1” mean in the description
These are the levels of the lumbar spine. L4-L5 = the space between the 4th and 5th lumbar vertebrae (the most common location for disc herniation ~60% of cases); L5-S1 = the last lumbar disc (second most common ~30%); L3-L4 and above are rarer. Each level innervates a different area of the leg: L4-L5 → pain in the buttock and back of the thigh; L5-S1 → pain radiating to the calf and big toe.
How a radiologist assesses nerve root compression
An MRI shows with high precision whether a herniated disc is compressing a nerve root (so-called “compression”). This is fundamental clinically relevant information. The report may state: “no compression” (asymptomatic, 60% of herniations in healthy people!); “contact” (it touches but does not deform); “compression” (it deforms the root); “compression with swelling” (the most severe degree, an indication for aggressive treatment). The clinical-radiological correlation is crucial—not every herniation causes symptoms.
Spinal canal stenosis – what is it?
Stenosis = narrowing of the spinal canal through which the spinal cord and nerve roots pass. It can be congenital or acquired (due to aging, disc disease, or ossification of ligaments). An MRI shows the degree of narrowing. Classic symptoms: neurogenic claudication – pain and numbness in the legs that appear after a short walk and subside when sitting (unlike vascular claudication, where sitting does not help). Stenosis often requires surgical treatment.
Modic changes – a red flag in the description
Modic changes in the vertebral bodies are bone swelling or sclerosis. Modic 1 (swelling) = active inflammation, often severe pain; Modic 2 (fatty degeneration) = chronic; Modic 3 (sclerosis) = late stage. Modic 1 is clinically the most significant—it often correlates with severe pain and responds to targeted treatment (injections, anti-inflammatory drugs). If you see “Modic 1” in the description, this is an important clue for the therapist.
Frequently Asked Questions
Does every herniated disc require surgery?
No. Only 5–10% of herniations require surgery. Most resolve within 3–6 months with conservative treatment (physical therapy, exercises, anti-inflammatory medications).
I have a 5 mm herniation—is that a lot?
Size isn’t the most important factor. What matters is whether it’s compressing a nerve root and causing symptoms.
Will an MRI show why I have back pain?
In ~85% of cases of lower back pain, an MRI does not reveal a structural cause. Often, the pain is muscular or postural.
I have a herniated disc at age 30—will it get worse?
With proper care (exercise, posture, weight management), most patients stabilize and live normal lives.
Can I play sports with a herniated disc?
Yes, most sports. Just avoid dynamic movements like lifting and jumping without proper muscle conditioning.
How long should I wait before repeating the MRI?
Only if your symptoms change or before a planned procedure. Routine repeat scans are unnecessary.
This content is for informational purposes only and does not replace a medical consultation.
