What is a Lumbar Disc Prolapse?
Spinal discs act as shock absorbers between vertebrae to which they are bonded. A lumbar disc prolapse, also known as a ‘herniated’ or ‘slipped’ disc, is a condition where a fragment of soft central disc material squeezes out under pressure through a tear in the disc capsule (annulus). The prolapsed fragment may compress an adjacent nerve root or multiple roots to cause neurological symptoms (Fig1).
What are the symptoms?
Lumbar disc prolapse is most commonly seen between the age of 35 and 55. The episode can be caused by heavy lifting, bending and twisting of the spine, or even mild activity or at rest. Patients usually experience sudden onset low back pain followed by pain radiating into the buttock, thigh, calf, or shin (sciatica).
At first, the pain is very severe but tends to settle after about two weeks with the help of pain medication, reduced activities and physiotherapy. The pain is often described as a deep dull ache but can be a sharp stabbing pain. This may be accompanied by numbness, tingling or muscle weakness in hip, knee or ankle movements. The sciatica is typically worsened by coughing, sneezing, bending or prolonged sitting.
What investigations are required?
A spinal disc prolapse disc is best seen on a spinal MRI scan which provides very detailed images of the spinal structures including the nerves and discs. X-Rays are not useful for diagnosing this condition and involve unnecessary radiation.
What are the treatment options and prognosis?
The majority of patients improve over a period of four to eight weeks with conservative treatment which includes pain medication and reduced activity. They may also benefit from physiotherapy or acupuncture. Forceful spinal manipulation should be avoided as it has the potential to aggravate the pain or cause nerve damage.
Despite these initial conservative treatment measures, about one in four patients do not improve or continue to worsen. These patients are usually referred to a consultant spinal specialist for further assessment and advice. Depending on the individual case, the specialist may recommend ongoing conservative management, a steroid Nerve Root Block or a Lumbar Microdiscectomy operation.
If a patient develops worrying leg or ankle muscle weakness, or problems with bladder or bowel function, then urgent referral to a spinal surgeon is usually advised, as it may be necessary to operate sooner rather than later.