Why?
This is an extremely common condition, frequently referred to as a ‘slipped disc’. The central portion of the lumbar disc (nucleus pulposis) bulges through the surrounding fibrous tissue (annulus fibrosis) and may cause irritation or compression of an adjacent nerve. This often occurs in the presence of an abnormal or degenerate disc, which has a small tear in the annulus fibrosis.
This may cause leg pain, with associated numbness, and weakness. Occasionally the disc may compress the sac of nerves at the end of the spine called the cauda equina (see cauda equina syndrome), which may damage the nerves controlling bladder, bowel and sexual function.
When?
In most patients the symptoms improve within six weeks with physiotherapy treatment and analgesics. If the pain persists or there is weakness in the leg or concerns about cauda equina compression then the diagnosis of a disc prolapse can be made with an MRI scan.
What other treatment options are there?
The majority of patient’s symptoms will resolve without interventional treatment and require simple analgesics and physiotherapy. If the pain persists despite these measures a confirmed disc prolapse may be treated with a nerve block.
Nerve Root Blocks
This procedure is used when pain relief is required, yet surgery is not immediately indicated. It eases the pain while the disc prolapse resolves. (See Nerve Root Block).
Prior to surgery
Prior to surgery you will be explained the natural history of the condition (what is likely to happen without treatment). Most patients experience relief of symptoms without surgery. Other treatment options will then be discussed and the surgical procedure will be explained including the postoperative care and potential complications (see Complications), prior to you consenting to undergo the operation.
Surgery is indicated under following circumstances.
- Central disc prolapse pressing on the nerves to the bladder or bowel (cauda equina syndrome)
- Progressive weakness within the leg
- Severe leg pain not responding to conservative measures within the first 6 weeks of onset
- Persistent pain affect activities at 6 weeks or more following surgery
After surgery, 75% of sciatica patients are very much better. 20% are improved but have some minor persisting symptoms. About 5% of patients are not helped and about 1% may even be worse off.
Surgery
A general anaesthetic is required and once this is administered the patient is placed on their front. An X-ray machine is used to localize the area of the spine that needs to be operated on. This allows the surgery to be made through a smaller scar and reduces the risks of scar tissue forming around the nerve and causing post-operative pain.
The muscles around the spine are moved out of the way, and a small hole or foraminotomy is made in the soft tissues or bon to gain access to the prolapsed disc.
The nerves are carefully reflected out of the way and the disc prolapse is removed, thus reliving the pressure on the nerve. The annulus is left in position.
Post operative care
On the evening of the surgery or the following day you will be able to mobilise with the help of the nursing staff. You will reviewed by your operating surgeon the day after surgery and the majority of patients will go home that day. You will be seen by a physiotherapist prior to discharge home and encouraged to mobilise as much as possible. Plans will be made for physiotherapy treatment within the outpatient department.
How long until I am better?
When pressure is taken off a nerve the first symptom to improve is pain, which may be immediate. It takes a longer time for muscle weakness to improve. If there has been any muscle wasting (loss of muscle bulk) this frequently never recovers, even though the strength often does. The last symptom to improve is numbness, which sometimes never recovers fully. After surgery it is not uncommon to have various aches and pains in and around the wound, and in the bony pelvis, hips and thighs. These usually improve with time. For the first few weeks postoperatively, your sciatica may return because of nerve swelling.
It is very helpful to have seen a physiotherapist before your surgery and even more important to see one postoperatively. You can receive heat, ultrasound and massage, information on exercises and on how to move and how to build up your core [back and abdominal] muscles long-term in order to help best maintain the strength of your back.
Patients usually return to work between four to six weeks following surgery depending on their job.
