Introduction

Spinal stenosis is a disorder caused by the narrowing of the spinal canal, or the neural foramina (the space through which the spinal nerve roots pass), which results in ischaemia of the nerve roots. It should be considered a clinical syndrome – as its aetiology typically defines it as an advanced stage of several other diseases.

It typically occurs in the lumbar or cervical spine. Features include:

  • Cervical
    • Neck pain
    • Loss of fine motor control in upper limbs
    • Loss of sensation in upper and lower limbs
    • Urinary incontineince
  • Lumbar
    • Neurogenic claudication

It is most commonly a degenerative disorder in older patients, caused by any or all of:

  • Osteophyte formation
  • Loss of intervertebral disc height
  • Hypertrophy of the ligamentum flavum

Many patients are asymptomatic. In some severe cases it may progress to spinal cord compression.

MRI of spinal stenosis

MRI of lumbar spinal stenosis – showing compression at multiple levels. This file is taken from wikimedia commons and is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.

Epidemiology

  • A disease of old age
  • Symptomatic spinal stenosis occurrs in about 10% of the population
    • Incidence of cervical and lumbar is similar – both about 10% – with a lot of overlap
    • In one study, 47% of individuals aged over 60 had evidence of stenosis on imaging
  • The incidence is expected to increase with the ageing population

Aetiology

Risk factors include:

Presentation

  • Cervical
    • Neck pain
    • Loss of fine motor control in upper limbs
    • Loss of sensation in upper and lower limbs
    • Urinary incontinence
    • Typically it is the lower cervical vertebrae that are affected, and the upper are spared
  • Lumbar
    • Neurogenic claudication
      • Pain in the lower limb caused by exertion. Typically starts in the buttocks and then advances down the legs. May be associated with weakness and numbness in the lower limbs
    • Lumbar pain and / or buttock pain
      • Typically dose on standing, walking or lumbar extension
      • Relieved by sitting or lying flat, raising legs or flexion
      • Back pan occurs in about 50% of patients
      • Cycling may be much easier than walking (flexed position)
    • Neurological signs
      • Numbness
      • Weakness
      • Neurological examination is often normal
    • Take care to differentiate from the vascular claudication caused by peripheral vascular disease
      • Perform a vascular examination
      • This pain typically starts in the calves and progresses UP the legs

Differential diagnosis

Investigations

  • X-ray
    • Might be useful to show signs of some differentials
    • Not specific enough to make a diagnosis of spinal stenosis
  • MRI
    • The diagnostic tool of choice
    • Good at imaging the spinal soft tissues
  • CT
    • May show some of the bony changes, but not always very good at showing if these are actually causing compression of the spinal cord or nerve roots

Management

Cervical spinal stenosis typically does not respond well to conservative management, and tends to be treated surgically earlier than lumbar spinal stenosis.

Lumbar spinal stenosis, even that with neurogenic claudication, tends to respond well to conservative measures, and the evidence for surgical treatment benefit is poor.

  • Conservative management will improve function to normal levels in 50% of patients in lumbar spinal stenosis

Conservative management

  • Physiotherapy – particularly forward flexion exercises
  • NSAIDs – e.g. ibuprofen 400mg TDS
  • Weight loss if BMI >25
  • Epidural injections – may provide short term relief
  • Medication for neuropathic pain
    • e.g. amitriptyline 10-25mg nocte, increasing to max 75-100mg nocte
    • Gabaptenin
    • Pregabalin

Surgery

  • Decompression
  • Decompression + fusion
    • Evidence suggests is no better than decompression alone
  • Active rehabilitation is important and improves outcomes
  • Surgery seems to give quick symptom relief int he short-to-medium term, but outcomes at 3-5 years are similar to conservative management
    • This is similar to the surgical outcomes seen in discectomy procedures for sciatica

References

  • Lumbar spinal stenosis - patient.info
  • Murtagh’s General Practice. 6th Ed. (2015) John Murtagh, Jill Rosenblatt
  • Oxford Handbook of General Practice. 3rd Ed. (2010) Simon, C., Everitt, H., van Drop, F.
  • Beers, MH., Porter RS., Jones, TV., Kaplan JL., Berkwits, M. The Merck Manual of Diagnosis and Therapy

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