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Spinal Disc Problems (including Red Flag Signs)

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PatientPlus articles are written by UK doctors and are based on research evidence, UK and European Guidelines. They are designed for health professionals to use, so you may find the language more technical than the condition leaflets.

See also: Slipped (Prolapsed) Disc written for patients

Disorders affecting intervertebral discs include:

  • Disc herniation (prolapsed intervertebral disc).
  • Degenerative disc disease.
  • Infection (discitis).

Spinal disc problems can lead to symptoms of back pain and/or sciatica. There are many other causes of back pain and/or sciatica but they do not primarily originate from the intervertebral discs. This article focuses on thoracic, lumbar and sacral disc problems. Cervical disc problems are discussed in the separate article Cervical Disc Protrusion and Lesions.

Back pain with/without sciatica is extremely common. Most may be classified as 'simple' back pain where serious underlying pathology is unlikely. However, the clinician must always be aware of 'red flag' warning signs which may merit investigations or even emergency admission.

  • The spinal cord is shorter than the spinal canal. The cord ends between the L1 and L2 vertebrae in adults and between L2 and L3 in children.
  • Below the termination of the cord, the nerve roots form the cauda equina which has a horse-tail like appearance. The cauda equina contains the nerve roots L1-L5 and S1-S5. Spinal pathology below L1 of the vertebral column produces mostly lower motor neurone signs.
  • The intervertebral discs lie between adjacent vertebrae. They consist of a peripheral fibrocartilaginous part called the annulus fibrosus and a central semifluid/gelatinous part - the nucleus pulposus.

This is described in detail in the separate articles Examination of the Spine, Low Back Pain and Sciatica and Neurological Examination of the Lower Limbs.

Red flags for back pain[2]

  • Red flags that suggest cauda equina syndrome include:
    • Saddle (perianal/perineal) anaesthesia or paraesthesia.
    • Recent onset of bladder dysfunction.
    • Recent onset of faecal incontinence, unexpected laxity of the anal sphincter.
    • Severe or progressive neurological deficit in the lower extremities.
  • Red flags that suggest spinal fracture include:
    • Sudden onset of severe central pain in the spine, which is relieved by lying down.
    • Major trauma such as a road accident or fall from a height.
    • Minor trauma, or even just strenuous lifting, in people with osteoporosis.
    • Structural deformity of the spine.
  • Red flags that suggest cancer or infection include:
  • Red flags that suggest spondyloarthropathy include:
    • Early morning stiffness lasting > 45 minutes.
    • Night pain.
    • 'Gelling'.
    • Easier with movement/ worse after rest.
  • Red flags that suggest a high risk of permanent damage to the compressed nerve include:
    • Significant muscle weakness or wasting.
    • Loss of tendon reflexes.
    • Presence of a positive Babinski reflex (toes extend and fan outwards when the lateral part of the sole of the foot is stimulated).

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  • If red flags suggest a serious condition:
    • Refer with appropriate urgency.
  • If there is progressive, persistent, or severe neurological deficit:
    • Refer for neurosurgical or orthopaedic assessment (preferably to be seen within one week).
  • If pain or disability remains problematic for more than a week or two:
    • Consider early referral for physiotherapy or other physical therapy.
  • If, after six weeks, sciatica is still disabling and distressing:
    • Refer for neurosurgical or orthopaedic assessment (preferably to be seen within three weeks).
  • If pain or disability continues to be a problem despite appropriate pharmacotherapy and physical therapy:
    • Consider referral to a multidisciplinary back pain service or a chronic pain clinic.
  • The nucleus pulposus of the disc is usually contained by the annulus fibrosus. If the nucleus herniates, it can irritate and/or compress the adjacent nerve root, causing symptoms of sciatica.
  • Traumatic disc herniation can occur. Disc herniation can also occur secondary to degenerative disc disease.
  • A herniated nucleus pulposus is most common in those aged below 40 years, whilst degeneration of discs tends to affect those aged over 40 years, with the prevalence increasing with advancing age. Disc lesions of the lumbar spine are more common than the cervical spine and disc lesions of the thoracic spine are rare.
  • The term sciatica is used for the pain, tingling, and numbness that arise due to nerve root entrapment in the lumbosacral spine. The symptoms may be felt in one or more of the lumbar nerve roots. About 90% of cases of sciatica are caused by a herniated intervertebral disc. This most commonly occurs at the L5/S1 level. See also separate Low Back Pain and Sciatica article.
Prolapsed disc


  • Lumbosacral disc herniation:
    • If there is nerve entrapment in the lumbosacral spine, this leads to symptoms of sciatica which include:[2]
      • Unilateral leg pain that radiates below the knee to the foot/toes.
      • The leg pain being more severe than the back pain.
      • Numbness, paraesthesia, weakness and/or loss of tendon reflexes, which may be present and are found in the same distribution and only in one nerve root distribution.
      • A positive straight leg raising test (there is greater leg pain and/or more nerve compression symptoms on raising the leg).
      • Pain which is usually relieved by lying down and exacerbated by long walks and prolonged sitting.[1]
    • The functional distribution of the lumbar nerve roots and the sciatic nerve are detailed in the separate Low Back Pain and Sciatica article.
    • Large herniations can compress the cauda equina leading to symptoms/signs of saddle anaesthesia, urinary retention and incontinence as described above.
    • Symptoms tend at least to resolve partially in 66% of people with a disc herniation, after six months. This is because the herniated portion tends to regress over time.[3]
    • However, nerve root compression can lead to permanent nerve damage with sensory and motor deficit.[2]
  • Thoracic disc herniation:[4]
    • Disc lesions in the thoracic spine can lead either to nerve root irritation or to cord compression.
    • Thoracic spine lesions can present with symptoms similar to lumbar disc lesions.
    • In nerve root irritation, there may be shooting pain down the legs.
    • There may be pain, paraesthesia or dysaesthesia in a dermatomal distribution.
    • A thoracoabdominal sensory examination can help to determine the level of the lesion: the nipple is innervated by T4; the xiphoid by T7; the umbilicus by T10; the inguinal region by T12.
    • Testing of the abdominal and cremasteric reflexes can help to identify myelopathy and cord compression.
    • Cord compression:
      • This is a neurosurgical emergency.
      • Cord compression in the thoracic spine can produce paraplegia.
      • There may be clonus or a positive Babinski reflex.
      • There may be bladder/bowel dysfunction.
      • Herniation of T2-T5 can mimic cervical disc disease.


  • No investigation may be needed if symptoms settle within six weeks.
  • MRI is very sensitive in showing disc herniations.[1]
  • CT myelography may also be used.
  • Plain X-rays are sometimes useful, as they can show misalignments, instabilities and congenital anomalies well.[1]


Spinal cord compression or cauda equina syndrome are neurological emergencies that require immediate referral and intervention.
  • Analgesia:
  • Encouragement to keep active: swimming is a good exercise.
  • Heat and massage may relieve muscle spasm.
  • Avoidance of activities that may aggravate pain: eg lifting, prolonged sitting.
  • Physiotherapy
  • Surgery:
    • Pain due to a herniated lumbosacral disc may settle within six weeks. If it does not, or there are red flag signs such as the possibility of cauda equina syndrome, referral to an orthopaedic or neurosurgeon should be considered.
    • Interventions for people with chronic intractable pain or neurological complications include removal of the protruding disc (discectomy) and/or spinal fusion.[5]
    • The National Institute for Health and Clinical Excellence (NICE) recommends that prosthetic intervertebral disc replacement may be used in the treatment of symptomatic degenerative disc disease of the lumbar spine.[5]
    • NICE recommends that percutaneous intradiscal laser ablation in the lumbar spine may be considered as a treatment option.[6] The current evidence of percutaneous endoscopic laser lumbar discectomy is inadequate for it to be considered as a treatment option.[7]


  • Permanent nerve damage with sensory deficits and/or permanent motor weakness.
  • Psychosocial problems.
  • Loss of employment.


  • The prognosis for acute sciatica is favourable for most people. The herniated portion of an intervertebral disc causing sciatica tends to regress over time and 66% of people have at least partial resolution after six months.
  • About 50% of people with acute sciatica report some improvement within ten days and about 75% reported some improvement after four weeks. However, up to 30% of people continue to have pain for one year or longer.
  • The prognosis is worse for women and people who initially have greater disability or pain.


  • Regular exercise.
  • Weight loss if overweight.
  • Safe lifting techniques.
  • Correct sitting position and posture.
  • The exact cause of this is not known. Some suggest that it is a natural part of ageing; however, disc degeneration can also occur in young people. The cause is likely to be multifactorial, including genetic, environmental, traumatic, inflammatory, infectious and other factors.[8]
  • Annular tears, internal disc disruption and resorption, disc space narrowing, disc fibrosis and osteophyte formation can all occur.[8]
  • Degenerative disc disease may lead to disc herniation.


  • Discitis is inflammation of the vertebral disc space. It is usually associated with infection and can co-exist with vertebral osteomyelitis (spondylodiscitis).
  • It most commonly affects the lumbar spine. The thoracic spine is least commonly affected with the cervical spine between the two.
  • There is usually haematogenous spread of infection from other parts of the body. The urinary tract, lungs and soft tissues are common primary sites for infection. It may be difficult to find a primary site.
  • Staphylococcus aureus is the most common pathogen.
  • Discitis can occur in children but most commonly affects males aged in their 50s.
  • Risk factors include any cause of immunosuppression (including diabetes) and intravenous drug use.
  • Discitis may rarely follow surgery involving the disc space.


Diagnosis is difficult and often delayed or missed due to the rarity of the disease and the high frequency of low back pain in the general population.[10]

  • An insidious onset is common, with neck or back pain and localised tenderness. Pain is worse on movement. Mobility may be restricted.
  • There may be associated fever and weight loss.
  • Neurological deficit may be present. This is more likely in the cervical spine.


  • ESR and CRP are raised. They can be used to monitor response to treatment.
  • White blood cell count may be normal.
  • Blood cultures, sputum, urine and any other appropriate cultures should be taken to look for the source of infection.
  • X-ray of the spine may show disc space narrowing, end-plate irregularities and annulus calcification. Osteomyelitis changes may be seen including decreased bone density and bone destruction. However, X-ray may be normal initially.
  • Nuclear medicine scans may be helpful.
  • CT and MRI scanning show changes earlier than plain X-ray. MRI is the most sensitive and specific.
  • CT-guided or open biopsy of the infected disc space area can provide histological confirmation of discitis and allow culture. Surgical debridement may be carried out at the same time.


  • Antibiotics are needed. These should be adjusted if/when culture results are available. Parenteral treatment is usually used and may be needed for 6-8 weeks. ESR can be used to monitor response.
  • Immobilisation: two weeks of bed rest have been suggested, followed by immobilisation with a brace, which may be needed for 3-6 months.
  • Analgesia should be prescribed as required.
  • Surgical treatment may be needed if there is neurological deficit, spinal deformity or lack of response to antibiotic treatment.


  • Antibiotic treatment with/without surgery is usually successful in treating the condition.
  • 15% of people have permanent neurological deficits.
  • Complications can include spread of infection into the epidural space or paraspinal soft tissues.
  • Mortality is reported as 2-12%.

Further reading & references

  1. Sahrakar K et al, Lumbar Disc Disease, Medscape, Nov 2011
  2. Sciatica (lumbar radiculopathy); NICE CKS, November 2009 (UK access only)
  3. Jordan J, Konstantinou K, Shawyer MT, Weinstein J; Herniated lumbar disc. BMJ Clinical Evidence. BMJ Publishing Ltd. 2007.
  4. Hannani K, Thoracic Disc Injuries, Medscape, Feb 2010
  5. Prosthetic intervertebral disc replacement, NICE Interventional Procedure Guidance Guideline (July 2009)
  6. Percutaneous intradiscal laser ablation in the lumbar spine, NICE Interventional Procedure Guideline (September 2010)
  7. Percutaneous endoscopic laser lumbar discectomy, NICE Interventional Procedure Guideline (May 2009)
  8. Patel RK, Lumbar Degenerative Disk Disease, Medscape, Nov 2010
  9. Jallo GI, Diskitis. Medscape, Feb 2011
  10. Gouliouris T, Aliyu SH, Brown NM; Spondylodiscitis: update on diagnosis and management. J Antimicrob Chemother. 2010 Nov;65 Suppl 3:iii11-24.

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.

Original Author:
Dr Michelle Wright
Current Version:
Peer Reviewer:
Dr Helen Huins
Document ID:
3900 (v26)
Last Checked:
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