Acute and non acute Schmorl’s nodes,disc vascularization : MR findings & recent concepts

 

Disc degeneration itself is a normal process in the elderly, beginning

as early in the twenties. There are 3 complications of degenerative disease of

the spinal column, making the normal process to a pathologic condition for

the individual : disc hemiation, spinal stenosis, and erosive osteochondritis.

MRI of erosive osteochondritis is characterized by disc vascularization and

bone marrow edema, both imaging features also found in infectious

spondylitis. Schmorl’s nodes can become vascularized like disc tissue in

erosive osteochondritis. There exist two types of Schmorl’s nodes: intraosseous

hemiation of nucleus pulposus tissue through the cartilaginous

endplate and hyaline cartilage proliferation originating in the trabecular bone

in erosive osteochondritis.

In disc degeneration, erosions of the adjacent vertebral endplates can be

present. However, the peripheral cortical bone of the vertebra is intact in disc

degeneration and frequently sclerosis can be found. Disc infections, on the

other hand, are frequently associated with destruction of the cortical borders

of the vertebra, the distinct dark rim of the endplate is then often focally not

visible on T1-weighted images. A gas density on CT is helpful to

distinguish degenerative disc vascularization in erosive osteochondritis from

spinal infection.

There is a high prevalence of degeneratively affected lumbar discs in MRI

examinations of people without back pain, and all degrees of disc

degeneration can be generally found in asymptomatic populations. However,

band-like vascularity in the disc space at the disco-vertebral junction is

associated with severe painful back syndromes . As bony changes and spurs at the endplates

are absent or only moderately developed segmental instability may play a causative role in

 the development of disc vascularity. Secondary disc vascularization represents a clinical condition

which can be diagnosed easily only by means of contrast enhanced MRI.

Therefore, MRI protocols in the work-up of patients with painful back

syndromes should include the application of paramagnetic contrast medium

and sagittal imaging planes after contrast medium injection, when previous

CT studies do not show disc herniation or other significant findings to explain

the patients symptoms. Degenerative disc vascularization is an important

differential diagnosis to bacterial spondylitis. It can be causative for pain in

patients with post-discectomy syndrome.

Gadopentetate dimeglumine enhanced MR imaging examinations of the

lumbar and thoracic spine is indicated for Schmorl’s nodes,

vascularization of Schmorl’s nodes, and associated bone marrow edema.

Sagittal T2-weighted SE and T1-weighted enhanced and non-enhanced SE

images with and without fat suppression  may be employed.

 

 

 

As the prevalence of Schmorl’s nodes decreases with age from youth to

adulthood, healing may be possible. Therefore, proliferative processes must

take place in the area of intraosseous herniation. At postmortem microscopic

examination, abnormal cartilage proliferation was noted in a 16 years old boy

with juvenile kyphosis in abnormal vertebrae and growth plates. In the

peripheral regions of the Schmorl’s nodes, where the vertebral bodies are in

contact with the node, growth of cartilaginous cells can occur. After

intraosseous herniation, ingrowth of vessels takes place from the adjacent

bone marrow into the periphery of the node and will progress to the center of

the node. It can be hypothesized that vascularization is requisite for cartilage

formation. Subsequent ossification contributes to sclerosis. By this

mechanism, sclerotic healing may be possible after ossification of the

cartilage.

 Only very few Schmorl’s nodes become symptomatic. Vascularity may be a

normal attempt to heal intraosseous cartilaginous hernias and is not

necessarily accompanied by back pain. However, enhancing Schmorl’s nodes

were bigger and more often accompanied by bone marrow edema in patients

with back pain than in those without. Enhancing Schmorl’s nodes should not

be confused with tumor or infection.

 

 

 

Suggested reading:

 

1.

Modic MT, Steinberg PM, Ross JS, Masaryk TJ, Carter JR
Degenerative disc disease: asessment of changes in vertebral bony
marrow with MR imaging.Radiology 1988; 166:193-199

 

2.Ross JS, Modic MT, Massaryk TJTears of the annulus fibrosus: assessment
with Gd-DTPA-enhanced MR imaging.AJR 1990; 154:159-162

 

3.Hamanishi C, Kawabata T, Yosii T, Tanaka SSchmorl’s nodes on
magnetic resonance imaging. Their incidence andclinical relevance.
Spine 1994; 19:450-453

 

4.Resnick D, Niwayama GIntravertebral disk herniations:
Cartilaginous (Schmorl’s) nodes.Radiology 1978; 126:57-65

 

5.Martel W, Seeger JF, Wicks JD, Washbum RLTraumatic lesions
of the discovertebral junction in the lumbar spine.Am J Roentgenol
1976; 127:457-464
6. Dr Axel Staebler, M.D. MR in D/D of disc space pathology :
Disc vascularization in acute degeneration ,
spondylitis,enhancing schmorls nodes :

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One comment on “Acute and non acute Schmorl’s nodes,disc vascularization : MR findings & recent concepts

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