Spinal stenosis

Spinal stenosis is characterized by the narrowing of the central spinal canal, intervertebral foramen, and/or lateral recess within the cervical spine, thoracic spine, or lumbar spine, resulting in progressive nerve root compression. It is commonly caused by degenerative joint disease and most often occurs in middle-aged and elderly individuals. Lumbar spinal stenosis is the most common form and causes load-dependent lower back pain that radiates to the buttocks and legs. Lumbar extension (standing or walking downhill) exacerbates the pain (pseudoclaudication or neurogenic claudication), while lumbar flexion (sitting or walking uphill) improves symptoms. Imaging, preferably MRI without IV contrast, and the presence of clinical features are required to confirm the diagnosis. Treatment of lumbar spinal stenosis initially involves conservative therapy (analgesia and physiotherapy); patients with refractory or severe spinal stenosis often require surgical decompression of the spinal cord (laminectomy). Cervical and thoracic spinal stenosis are less common and patients typically present with symptoms of myelopathy; management involves surgical decompression in most cases, with conservative therapy reserved only for mild cases.

• Incidence ^[1][2]
  • Lumbar stenosis is the most common form of spinal stenosis (affects ∼ 5 individuals per 100,000 population).
  • Cervical stenosis affects 1–2 individuals per 100,000 population.
  • Thoracic stenosis is rare.
• Age range: middle-aged and elderly population

Epidemiological data refers to the US, unless otherwise specified.

Progressive narrowing of the central spinal canal, intervertebral neural foramen, and/or lateral recess (cervical C2 or lumbar spine L1) caused by any of the following: ^[1][3][4]

• Degenerative joint disease (most common)
  • Spondylolisthesis (anterior or posterior)
  • Disk space narrowing (e.g., due to osteoarthritis and/or degenerative disk disease)
  • Facet joint hypertrophy
  • May affect both the lumbar and cervical spine simultaneously (tandem spinal stenosis)
• Iatrogenic: following spinal surgery such as laminectomy
• Systemic disease: Paget disease, ankylosing spondylitis, tumors
• Others: e.g., trauma, calcification of the ligamentum flavum, uncommon congenital malformations (e.g., open spinal dysraphism)

All levels

• Pain is most often gradual onset, chronic, or subacute, depending on the etiology.
• Acute pain can occur due to an exacerbation of a chronic underlying process or complication (see “Acute back pain” for details).
• Radiculopathy (at various affected vertebral levels) often occurs alongside spinal stenosis features, typically due to comorbid etiology, e.g., degenerative disk disease.

Lumbar spinal stenosis ^[3][5]

• Load-dependent lower back pain that worsens with walking
• Neuropathic claudication: a group of neuropathic symptoms affected by postural changes ^[6]
  • Unilateral or bilateral gluteal, thigh, and calf pain
  • Worsens with lumbar extension (e.g., walking, prolonged standing)
  • Relieved by lumbar flexion (e.g., sitting, laying down, cycling)
  • See also “Neuropathic claudication vs. vascular claudication.”
• Unsteady wide-based gait
• Reduced lower extremity reflexes
• Mild motor weakness and sensory changes may be present.
• Abnormal Romberg test

Leaning on a shopping cart to alleviate pain (so-called “shopping cart sign”) is a common clinical feature in patients with lumbar stenosis. ^[7]

Cervical spinal stenosis ^[8]

Clinical features are those of myelopathy and vary depending on the level of cord compression. Pain is less common compared with lumbar spinal stenosis.

• Neck pain
• Gait and balance disturbances
• Increased urinary frequency or incontinence
• Upper motor neuron signs below the level of stenosis
• Lower motor neuron signs at the level of stenosis
• Sensory abnormalities: pain, paresthesia, and/or anesthesia at or below the level of stenosis; Lhermitte sign

Lhermitte sign should prompt evaluation for cervical stenosis, especially in elderly patients. ^[8]

Thoracic spinal stenosis ^[9]

As with cervical spinal stenosis, clinical features are those of myelopathy and vary depending on the severity and level of cord compression. They include:

• Unilateral or bilateral lower limb paresthesia and pain
• Bladder, bowel, and/or sexual dysfunction
• Radicular pain around the chest or abdomen
• Upper motor neuron signs in the lower limbs

Approach ^[3]

• Characteristic clinical features present: Confirm diagnosis with imaging.
• Mild to moderate symptoms PLUS signs of stenosis on imaging: Consider adding EMG.
• Acute exacerbation and/or new associated symptom of concern: Follow approach for “Acute back pain”.

A diagnosis of spinal stenosis requires the presence of both findings on imaging and clinical features of spinal stenosis.

Neuroimaging ^[3][10]

• Modalities and indications
  • MRI spine without IV contrast: preferred modality in symptomatic patients ^[3]
  • CT myelogram: preferred modality in patients with contraindications to MRI or if MRI is inconclusive ^[11]
  • CT spine without IV contrast: Consider in patients with contraindications to MRI and CT myelogram.
  • CT or MRI with axial loading : Consider in symptomatic patients with equivocal findings on imaging or to identify spinal instability. ^[3][12]
• Findings ^[9][10][13]
  • Evidence of spinal stenosis
    • Narrowing of the spinal canal
    • Compression of the spinal cord and/or nerve root impingement
  • Evidence of the underlying etiology (e.g., degenerative disk disease, facet joint hypertrophy, ligamentous hypertrophy)

Obtain an urgent MRI spine (with and without IV contrast) and neurosurgery consult for patients with rapidly progressive neurological deficits suspicious for spinal cord compression, cauda equina and/or conus medullaris syndrome

X-ray spine

• Indications
  • Routine first-line modality for acute back pain in individuals with no neurological abnormalities
  • Suspected vertebral fracture
  • Patients due to undergo surgical treatment with suspected spinal instability: Consider dynamic studies (e.g., imaging in flexion and extension) to identify spinal instability. ^[10][14]
• Findings: evidence of the underlying etiology
  • Degenerative joint changes (e.g., loss of disk height, osteophytes, loss of vertebral alignment)
  • Congenital abnormalities (e.g., scoliosis, lumbosacral transitional vertebrae)
  • Disk herniation
  • Hypertrophy of facet joint

• The differential diagnoses of low back pain and acute back pain are broad and are detailed separately.
• In patients with claudication, neuropathic claudication should be differentiated from vascular claudication.

The differential diagnoses listed here are not exhaustive.

Lumbar spinal stenosis ^[3]

• Mild or moderate symptoms: conservative management with analgesia and physiotherapy
• Significant symptoms or inadequate response to conservative management: Consult neurosurgery for consideration of operative management.

Conservative management ^[15][16]

• First-line
  • NSAIDS (see “Oral analgesics” for agents and dosages)
  • Physiotherapy
• Second-line: (persistent neuropathic claudication or radiculopathy): neurosurgery and/or pain specialist (anesthesia, physiatry) consult for consideration of image-guided epidural steroid injection ^[3][17]

Surgery

• Indications ^[3]
  • Severe lumbar stenosis
  • Moderate lumbar stenosis with insufficient response to conservative therapy
  • Patients who elect to undergo surgery
• Surgical options to relieve spinal cord compression ^[3][18][19]
  • Laminectomy (decompression surgery)
    • Removal of the dorsal part of the involved vertebra (lamina), thereby relieving the spinal compression
    • Can be combined with vertebral fusion (e.g., in patients with dynamic instability)
  • Laminotomy: minimally invasive removal of part of the lamina
  • Interspinous process spacer devices: Small implants are placed between the spinous processes in a minimally invasive procedure.
• Outcome: high recurrence rate with all forms of surgical management ^[20]

Cervical and thoracic spinal stenosis ^[9][21][22]

There is a paucity of evidence on the optimal management of cervical and thoracic stenosis.

• Surgery (decompression with or without vertebral fusion) is preferred in most cases because of the risk of severe neurological symptoms without surgical treatment.
• Conservative management (NSAIDs and/or physiotherapy) may be considered in patients with mild stenosis.

• Rarely, spinal stenosis may cause any of the following: ^[23]
  • Spinal cord compression
  • Cauda equina syndrome
  • Conus medullaris syndrome
• See also “Degenerative disk disease” and “Acute back pain.”

We list the most important complications. The selection is not exhaustive.