Sciatica

• What is Sciatica?
• Statistics
• Risk Factors
• Progression
• Symptoms
• Clinical Examination
• How is it Diagnosed
• Prognosis
• Treatment
• References

What is Sciatica?

Sciatica is defined as pain caused by pressure or irritation of the sciatic nerve. It can cause pain anywhere along the distribution of the sciatic nerve from the lower back to the sole of the foot. It can also cause changes in sensation and muscle power of the leg.
The sciatic nerve is a large nerve the size of a little finger. They originate from the spinal column in the lower back and travel behind the hip joint, down the buttock and down the back of the leg to the foot.

Statistics

Sciatica has been reported to occur in 1 to 10% of the population, most commonly in people age 25 to 45 years.

Risk Factors

Injury to the sciatic nerve is most commonly caused by entrapment of the nerve at the base of the spine, which may be related to prolonged sitting or lying with pressure on the buttocks. Most of the time people with sciatica do not recall a specific injury that caused the symptoms.
Sciatica can also be caused by pelvic fractures, gunshot wounds and other trauma to the buttocks or thighs. Spinal stenosis, which occurs as people get older, can but pressure on the sciatic nerve on both sides and this can result in sciatica on both sides of the body. Masses in the pelvis such as a tumour, abscess or bleeding can also put pressure on the sciatic nerve.

How is it Diagnosed

Sciatica is a clinical diagnosis and does not usually require any investigations. In some cases, when the diagnosis is uncertain or if the pain is not spontaneously resolving, imaging and other investigations may be required.

Prognosis

Approximately 90% cases of sciatica will resolve with conservative treatment, of which most gradually settle within 12 weeks (3 months).

Treatment

Acute sciatica:
Spontaneous recovery can be expected, however supportive treatment can include:

• Relative bed rest for no more than 2 days
• Return to normal activities as soon as possible
• Simple analgesics such as paracetamol (eg Panadol)
• 2 weeks of NSAIDs such as ibuprofen or naproxen
• Basic exercise such as swimming and walking should be continued
• Physiotherapy may be useful after the initial injury

Chronic sciatica:
If a trial of NSAIDs, rest and physiotherapy has not brought relief, an injection of local anaesthetic into the spinal (epidural space) may bring relief.
Surgical intervention:
There are some cases when surgery may be necessary in patients with sciatica, including:

• Loss of control of bladder or bowel function.
• Changes in sensation over the perineal area (around the genitals and anus).
• Progressive muscle weakness, such as foot drop or quadriceps weakness.
• Consider surgery in cases with severe prolonged pain or disabling pain, or failure of conservative treatment with persistent pain.

Prevention:
The following measures may help prevent sciatica:

• Weight loss
• Improved general physical condition
• Good back care

Complications
Complications of sciatica can include:

• Incorrect diagnosis
• Chronic low back pain
• Loss of bowel or bladder function
• Persistent numbness or weakness of the leg
• Addiction to pain killers if they are not prescribed appropriately
• Persistent psychosocial problems related to chronic pain

References

1. A.D.A.M. Medical Encyclopedia [Internet]. Atlanta (GA): A.D.A.M., Inc.; (c)2005. Sciatica; [updated 2004 August 3; cited 2006 April 2]; Available from: http://www.nlm.nih.gov/medlineplus/ency/article/000686.htm
2. Baldwin, J. Horwitz, J. Lumbar (intervertebral) disc disorders). eMedicine. 2006. Available at: http://www.emedicine.com/emerg/topic303.htm
3. Gibson JNA, Grant IC, Waddell G. Surgery for lumbar disc prolapse. The Cochrane Database of Systematic Reviews 2000, Issue 3. Art.
   No.: CD001350. DOI: 10.1002/14651858.CD001350.
4. Lex, J. Sciatica. eMedicine Consumer Health. 2006. Available at: http://www.emedicine.com/aaem/topic490.htm
5. Murtagh, J. General practice. 3rd ed. 2003. McGraw Hill. Sydney.
6. Watts, R. Silagy, C. A meta-analysis on the efficacy of epidural corticosteroids in the treatment of sciatica. Anaesth Intensive Care. 1995; 23: 564-569.