What are Schmorl nodes?

Schmorl's Nodes: Definition and Management

Schmorl's nodes are herniations of nucleus pulposus through the cartilaginous and bony endplate into the adjacent vertebra, most commonly found as incidental findings on imaging but occasionally becoming symptomatic and causing back pain. 1

Definition and Prevalence

• Schmorl's nodes represent displacement of intervertebral disc material (nucleus pulposus) through the vertebral endplate into the vertebral body
• Extremely common finding with postmortem studies estimating prevalence in >70% of the general population 2
• Most are asymptomatic and discovered incidentally on imaging studies
• First described by pathologist Christian Schmorl in 1927 3

Pathophysiology

• Several theories exist regarding formation, but the axial load model has the strongest supporting evidence 4
• Mechanical factors contribute to development:
  • Body weight is a significant risk factor (OR: 1.417) 5
  • Activity-related factors such as mechanical loading and impact stress on the spine 1
• Inflammatory response occurs when nucleus pulposus herniates into the well-vascularized vertebral body, which may cause pain 4

Clinical Presentation

• Most Schmorl's nodes are asymptomatic
• When symptomatic, they typically present as:
  • Acute or chronic back pain
  • Rarely, radiculopathy when there is posterior extension affecting nerve roots 1
• Associated with:
  • Intervertebral disc degeneration at upper lumbar levels (L1-L2, L2-L3)
  • End-plate disease at lower lumbar levels 5

Imaging Characteristics

• MRI is the imaging modality of choice for diagnosis 2
  • Better capability to detect edema and neovascularization
  • Can identify extruded disc material
  • Can detect surrounding cortical edema and enhancement in acute cases
• On CT, they appear as focal depressions in the vertebral endplates with an osteosclerotic rim 6
• May be confused with degenerative changes in older patients (median age ~70 years) 6

Management of Symptomatic Schmorl's Nodes

First-line Treatment: Conservative Management

• Physical therapy including:
  • Core strengthening exercises
  • Range of motion exercises
  • Proprioceptive training
  • Neuromuscular training 1
• Pain management:
  • NSAIDs for anti-inflammatory effects
  • Short-term opioid analgesia for severe pain
  • Muscle relaxants if muscle spasm is present 1

Interventional Procedures

• Epidural steroid injections for radicular pain
• Percutaneous vertebroplasty (PVP) for cases refractory to conservative treatment
  • Studies show immediate and long-term pain relief
  • Low complication rates with long-term follow-up 1, 7

Surgical Options (Reserved for Specific Cases)

• Segmental fusion surgery to stabilize affected segments
• Surgical removal of disc material in cases of persistent radiculopathy from a tunneling Schmorl's node
• Indicated only for:
  • Persistent disabling pain despite conservative and interventional treatments
  • Neurological deficits due to nerve compression 1, 2

Important Clinical Considerations

• Differential diagnosis should rule out other causes of back pain:
  • Vertebral fractures
  • Infections
  • Malignancy 1
• Red flags requiring urgent evaluation:
  • Fever
  • Weight loss
  • Night pain
  • Neurological deficits 1
• Schmorl's nodes can be differentiated from other lesions by their direct contact with the intersomatic disk and osteosclerotic rim 6

While most Schmorl's nodes are incidental findings, they should be considered in the differential diagnosis of back pain, particularly when other causes have been ruled out and imaging shows evidence of inflammation or nerve compression.