Schmorl's knot: symptoms, causes and treatment

Schmorl nodes are a common type of lesion that can occur in the spine. They occur when the tissue in the disc slips out and pushes up or down into the adjacent vertebrae.

Schmorl nodes usually do not cause any symptoms. Doctors can find them when they do imaging tests for other reasons. If a person has no symptoms, no treatment is usually needed.

However, if pain or mobility issues occur because of a Schmorl node, doctors may recommend conservative treatment with pain-relieving medication and rest.

This article looks at Schmorl’s node, its causes, diagnosis, and treatment.

Schmorl nodes, or herniated discs, are small, round lesions that form on the vertebrae, which are the bones that make up the spine.

They occur when a disc, a fibrous piece of cartilage that sits between each bone, herniates and pushes material from the inside into adjacent vertebrae and changes shape.

Discs often rupture laterally, but in a Schmorl node, the herniated disc extends up or down into the adjacent vertebra due to problems with the vertebral endplate. This structure sits between the discs and the bones and prevents the disc from bulging.

Intervertebral discs act as shock absorbers and are made up of a gelatinous core and a firm but flexible exterior. When the flexible part of a disc is twisted, the soft inner part can bulge. If the bulge touches the bone marrow inside the vertebrae, inflammation can occur.

Schmorl nodes can occur anywhere within the spine, but they most commonly affect the upper lumbar spine.

Schmorl knots are fairly common. They are commonly seen on MRIs of the lumbar spine, particularly in men.

According to a 2019 study, Schmorl nodes can be present in up to 76% of the general population. However, their prevalence varies widely, with some research suggesting that far fewer people develop Schmorl’s nodes than this.

Schmorl nodes are mostly asymptomatic, meaning people usually have no symptoms. They are often an incidental finding on MRI scans that doctors do to diagnose or monitor other conditions.

However, a person may experience an acute onset of low back pain or a worsening of chronic back pain after minor trauma. Rarely, Schmorl nodes can develop inflammation and infection.

Researchers believe that the weakening of the vertebral endplates causes Schmorl knots. However, these nodes can also have links to other conditions, such as:

  • Scheuermann’s disease, which causes the vertebra to grow unevenly in childhood
  • metabolic diseases
  • degenerative diseases of the spine
  • cancer of the spine
  • Spinal trauma or fractures
  • spinal infections

However, scientists are still learning more about it.

Schmorl nodes are not a type of cancerous growth. Doctors typically associate them with benign or benign disorders.

However, people can have Schmorl nodes and cancer at the same time. And in some cases, doctors can confuse one with the other.

For example, a 2015 case report describes a person with thyroid carcinoma metastases to the spine where thyroid cancer spreads to the spine. Initially, doctors thought the spinal growth was a Schmorl knot, according to the medical imaging tests they performed.

However, after biopsying the lesion, they found that the growth was actually due to the spread of thyroid cancer to other areas of the body.

The case study authors recommended that physicians closely monitor patients if they have a history of metastatic cancer or current cancer, even if imaging studies suggest a noncancerous diagnosis.

Doctors can diagnose Schmorl nodes using diagnostic imaging tests such as MRIs.

On an MRI scan, Schmorl nodules appear as small, bony abnormalities of the vertebral endplates. If imaging tests show features that resemble Schmorl’s nodes, doctors may also do tests to determine the underlying cause. Health care professionals particularly recommend these tests if other symptoms or signs of spinal disease are present.

Because most Schmorl’s nodes do not cause symptoms, treatment is often not needed.

However, if a person has painful Schmorl nodes, their doctor may suggest rest and pain medication. These include nonsteroidal anti-inflammatory drugs and acetaminophen.

Symptoms should resolve within 2 to 6 months, although it may take up to 12 months for any swelling seen on MRI to gradually subside.

If this conservative treatment approach does not provide symptom relief, the doctor may consider surgery to remove the damaged disc. One surgical technique is lumbar interbody fusion, in which the damaged disc is replaced with a bone graft. Surgeons will attempt to restore height between the vertebrae and encourage fusion of the two bones.

Schmorl nodes form when the soft discs between the vertebrae of the spine rupture or bulge through gaps in the vertebrae, the bones that make up the spine. Instead of bulging laterally, herniated discs protrude up or down, affecting the adjacent vertebrae.

The lesions are common and can affect up to 76% of the population. Usually they cause no symptoms and are not a cause for concern.

However, if a person has problems with pain and mobility, or has other conditions or symptoms that indicate a problem with the spine, they should speak to a doctor.