Dr. Kevin Yip

Dr Kevin Yip
Orthopaedic Surgeon
MBBS(UK), FRCS(EDIN), FAM(SING), FHKCOS(ORTHO)

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Schmorl Nodes

Basics
Description
  • Schmorl nodes are intraosseous vertebral lesions that are common incidental findings on plain radiographs and CT and MRI scans of the spine.
    • These nodes represent disc material that has herniated through weak areas in the adjacent vertebral endplates into the vertebral body.
    • In some cases, these weak areas may be the physiologic sequelae of the regression of vascular canals near the end of vertebral growth (particularly in young patients), whereas in other cases they represent a weakened endplate or subchondral bone.
    • Such herniations also may occur through pathologically weakened bone, and they usually are found in the thoracic or lumbar spine, although there have been reports of Schmorl nodes of the cervical spine.
  • These lesions were first described by Christian Georg Schmorl as the cause of Scheuermann kyphosis, which results from decreased growth of the anterior portion of the endplates of at least 3 adjacent vertebral bodies.
    • Although the origin of Scheuermann kyphosis remains unclear, Schmorl nodes are unlikely to be the cause because they are not universally present.
  • Synonyms: Vertebral endplate irregularities; Intraosseous disc herniations
Epidemiology
Incidence
  • ~10% of the general population
  • No gender predilection
  • Age ranging from childhood to old age, depending on the predisposing condition
Risk Factors
Genetics
  • No specific genetic correlation has been made.
  • Metabolic bone diseases with genetic predispositions may predispose persons to an increased incidence of intraosseous disc herniation secondary to decreased bone density or defective bony matrix of the vertebral bodies.
Etiology
  • Degenerative or acute rupture of the disc endplate and extrusion of the nucleus pulposus occur with sufficient force to penetrate the vertebral body superior or inferior to it.
  • Penetration may be secondary to acute trauma in the case of a normal vertebra and disc.
  • In the degenerative setting, penetration may occur slowly over time because of a weakened vertebral body.
  • Often, no obvious cause is found.
Associated Conditions
  • Scheuermann (juvenile) kyphosis
  • Trauma
  • Osteoporosis and other metabolic disorders
  • Neoplastic disorders
  • Degenerative disc disease
Diagnosis
Signs and Symptoms
  • Patients may be asymptomatic or may have pain secondary to Schmorl nodes.
  • Symptoms prompting radiographs may not necessarily be caused by this lesion.
  • Symptoms usually relate to the degenerative change or insufficiency of the particular disc and consist of axial backache or back pain.
  • Pain may radiate laterally around the trunk, but not distally down the extremities.
Physical Exam
  • Tenderness may or may not be elicited by deep palpation or percussion over the spine.
  • The degrees of kyphosis in the spine should be estimated.
  • A complete neurologic exam should be performed, but a neurologic deficit is unlikely.
    • If present, other causes should be sought.
Tests
Imaging
  • Conventional radiographs show indentations or pits in the vertebral body, with radiolucencies within the body surrounded by varying degrees of sclerosis.
    • Variable degrees of disc thinning may be present as a result of the displaced nucleus.
    • Benign-appearing lesions
  • MRI may show low signal on T1-weighted and high signal on T2-weighted images in the setting of acute intraosseous herniation, which is more likely to be symptomatic.
    • Old, usually asymptomatic lesions show the opposite findings on T1- weighted and T2-weighted images.
    • MRI is more sensitive than plain radiographs in detecting the lesion.
  • Bone scanning may be useful in differentiating an acute lesion from an older lesion, although MRI is the standard.
Differential Diagnosis
  • Degenerative subchondral cyst
  • Bone neoplasm: Osteoid osteoma, metastatic cancer to bone, aneurysmal bone cyst, early EOG, lymphoma, multiple myeloma
Treatment
General Measures
  • Treatment is symptomatic.
    • In the presence of an acute intraosseous herniation, NSAIDs and rest are the mainstay of care until the patient is able to resume normal activity.
    • Bracing may be initiated for comfort if needed.
Special Therapy
Physical Therapy
  • Physical therapy may help with persistent backaches.
  • Should consist of extensor strengthening and flexibility and endurance training
Medication
First Line
NSAIDs
Surgery
This condition is not a surgical entity.
Follow-up
Prognosis
Prognosis is generally good.
Complications
In the presence of loss of substantial disc space, degenerative joint disease of the facet joints may result, with additional symptoms.
Patient Monitoring
  • If the diagnosis is unclear, or if pain does not resolve within 6-8 weeks, serial radiographs should be taken to ensure that the lesion does not grow or change in character.
  • An MRI scan also may help rule out a malignant disease.
Miscellaneous
Codes
ICD9-CM
722.30 Schmorl node
Patient Teaching
FAQ
Q: With what spine condition are Schmorl nodes most commonly associated?
A: Scheuermann kyphosis.
Q: What is the recommended treatment for most patients with Schmorl nodes?
A: Observation and nonoperative management.

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