Sciatica is a common condition and has many other names. Some of these include ‘lumbar radiculopathy’, ‘slipped disc’, ‘torn disc’, and ‘disc prolapse’
These terms are all used to describe a pain that usually begins in the low back and spreads to the buttock, thigh, calf and foot, depending on which nerve root in the spine is irritated
The pain is very variable, and can vary from a bad toothache-like pain affecting the leg, to a severe electric-shock like pain shooting down the leg, or a dull ache in the leg which is difficult to pinpoint. These symptoms can be made worse by coughing or sneezing, excercise, and sitting rather than standing can aggrevate the pain. Additional symptoms that can be associated are tingling in the affected leg or foot, numbness, and occasionally weakness of the affected leg.
Symptoms that are worrying include severe sciatica affecting both legs, difficulting in passing urine, passing urine without knowing, a numb ‘bum’, and new weakness in one or more legs. If you have any of these symptoms you should contact you GP as a matter of urgency
Common Causes of Sciatica:
Prolapsed lumbar disc: The disc is made of a fibrous bag containing a more gelatinous core. As you get older the core becomes dehydrated and the bag may tear causing a disc prolapse to occur. The disc material is pushed backwards and can compress one of the nerves in your spine as it leaves to go to your leg. The brain is fooled into thinking the pain is coming from your leg, this is called ‘referred pain’
Lumbar stenosis: This is usually age-related and is due to wear and tear in the spine. It may otherwise be called ‘spinal degenerative disease’ and ‘spinal stenosis’. Wear and tear causes extra bone formation, typically this is around the neural foramen ( the canal where the nerves leave the spine.) The nerve is compressed by this bone and can cause sciatica. Typically the sciatica comes on after walking and is relieved with rest
Facet degeneration: The facets are small joints between the vertebra above and below, and lie posterior to the disc. These joints suffer wear and tear as part of the natural aging process and thus can become painful. Sometimes when a facet joint becomes inflamed and painful, the brain may be fooled into thinking the leg is painful and thus patients may get sciatica. This is due to referred pain in a very similar manner to nerve root compression. Investigation with an MRI scan typically shows no nerve root compression, but does show facet hypertrophy and wear. The treatment is very similar to that covered in the back pain section and very rarely involves surgery
Diagnosis of Sciatica
The diagnosis is based on an interview and examination. The next step is to decide whether you need further investigation. There is much debate over the timing of investigations for sciatica, this is largely due to the fact that the majority of patients’ sciatica will improve with no treatment after 6- 8 weeks. Thus if your pain persists beyond this period you may benefit from further investigation
The ideal investigation is an MRI scan. The image at the top of the page is a side view of the spine taken using an MRI scanner. The dark horizontal bands are discs, counting up from the bottom, the second disc is blacker, and has a bulge pointing backwards, this is a proplapsed disc of L4/5. Occasionally there is no obvious abnormality on the MRI scan to account for the sciatica. In these instances the pain is thought to be due to pain originating in small joints in the spine called ‘facet joints’. As part of the wear and tear process these joints can become inflammed and irritated and lead to back pain and a degree of sciatica, the sciatica due to facet disease usually is confined to the buttock and thigh. In patients who have had previous surgery on the lumbar spine scar tissue can build up around the nerve roots, this is called ‘epidural scarring.’ This scar tissue can tether the nerve roots and lead to sciatica, it is sometimes not visible on MRI scanning and thus may be a possible diagnosis in patients with pain after spinal surgery, and no nerve root compression on a follow-up MRI scan.
The vast majority (80%) of patients with sciatica will improve without any active treatment within 12 weeks. During this time investigation is not required unless there is sciatica in both legs, weakness, or difficulting passing urine. During this period it is best to remain as active as your pain allows, bed rest has not been shown to be effective treatment. The mainstay of treatment is medication with a non-steroidal painkiller such as diclofenac, low-impact excercise such as walking, swimming, cycling, and physiotherapy. Other treatments such as local injection of steroid into the spine by a pain specialist have also been shown to be beneficial
Only about 5% of patients with sciatica will require surgery to improve the pain. This is usually offered if the pain has not responded to the treatments above, and the pain has persisted beyond 6-8 weeks. Other factors that may mean surgery is offered are if there is a profound weakness in the leg due to the disc prolapse, or in cases of very big disc prolapse
Any operation proposed will be discussed with you. Surgery for sciatica is performed to improve leg pain, if you have a significant amount of back pain as well then this may not improve after surgery. The reasons for this are complex, it is thought that the back pain originates from a combination of muscle spasm in the spine, and wear and tear changes in the spine, whilst the muscle spasm may improve with treatment the wear and tear changes will remain and thus lead to continued back pain.
I perform operations specifically tailored to the location of the pain and appearances of the MRI scans, my preference is to perform minimally invasive surgery usually in the form of a microdiscectomy in combination with a foramenotomy. For larger disc prolapses or extensive degenerative changes I may perform a lumbar laminectomy and facetectomy. In the near future I will be able to perform a minimally invasive operation using a very small incision using the METRX system.
For more detail on these operations please visit the ‘Spinal Operations’ and ‘Keyhole Surgery’ pages.
Outcome of Treatment
Overall 80-90% of patients will have significant improvement in their symptoms after surgery.
Interestingly, a similar number of patients having non-operative treatment of their sciatica will have resolution of their sciatica after 4-5 years. Thus surgery should be seen as a way of speeding up the recovery, there is some additional evidence that patients having surgery earlier will have a better long-term result
The risks of surgery will be listed under the respective operation