There are a wide range of causes of sciatica, from simply a slipped disc to even infections or tumour. However, the latter are very rare. The vast majority of sciatica symptoms come from a slipped disc or wear and tear that’s built up over time. This is known as spondylosis which is a form of osteoarthritis of the spine.
Symptoms of sciatica
The symptoms of sciatica are generally defined as those from the distribution of the sciatic nerve and where it supplies the leg. This is usually pain down the back of the calf, the side of the calf on the outside predominately and also on the top of the foot and sometimes underneath the foot.
The vast majority of patients with sciatica will have discomfort for weeks or months, after which it should spontaneously resolve. Patients who usually end up having an intervention are those where symptoms have persisted or become more severe.
When to seek medical attention
A patient should attend their local accident and emergency or hospital urgently if they experience pain down both legs that’s sudden onset with weakness in the legs, weakness in the control of the bladder, bowels or rectal function or numbness around the genitals. This suggests that the nerves traveling down the centre of the spine in the lower back have been compressed which is a situation that warrants urgent surgical intervention.
When is surgery required?
Surgery is reserved for those patients who have had persistent pain despite trying the other modalities. What is important is if the patient has a weakness (a motor disability) in the muscle group that pertains to a particular nerve root that’s trapped in the spine, because there is a way that if disability occurs it may not improve spontaneously without intervention. In these cases, surgery is important.
Assuming the sciatic pain is being cause by a sliped disc, the standard microdiscectomy is the most common type of operation used. The patient stays for one night in hospital and during the operation, the patient is positioned on their front with a small incision made in the back to allow access to the back of the spine. We move the major nerve roots to the side to allow access to the disc itself and whilst protecting them, we remove as much disc that wants to come out (usually about 10 to 25% of the disk) rather than the entire disk. The patient can expect to be up and about the next day and they’ll hopefully have had improvement in their pain and to have noticed the difference. Sometimes, because the nerve has been squashed for a period of time, we may take the pressure off but the chemistry within the nerve may continue to tell the brain that there is something painful happening in the body.
Epidural and spinal injections are used as a second line after trying painkillers and physiotherapy or when the pain is so acute the patient needs a more dramatic or urgent relief. For lower spinal pain, epidural injections can be a very helpful. An alternative is targeted nerve root injections if the symptoms are pertaining to one nerve root’s distribution. Targeting just the one nerve can be sufficient. However, if there is more of a general lower back pain with more than one root, an epidural is very helpful because it treats multiple targets in the spine with steroid and local anesthetic.
Some of the stronger medications which may cause unwanted drowsiness during the day can conversely be more useful to take at night. They not only help with sleeping but they can help reduce the flow of information from the nerve erroneously to the brain to dampen down of those symptoms of pain.