Slip disc pain is one of the commonest reasons for a back or leg complaint in an orthopaedic clinic. The cushions between the bones of the spine are called discs, and a "slipped" disc is one that has bulged or torn so that its soft centre presses on a nearby nerve. The disc does not really slip out of place. Most people improve without an operation, and the first treatment is almost always non-surgical.
What is a slipped disc in the back?
Each disc has a soft, jelly-like centre inside a tougher outer ring. With age, strain or a heavy lift, the ring can weaken or crack and the centre pushes out. Doctors use words such as bulge, protrusion and herniation for this. A slipped disc in the back is most often in the lower lumbar spine, and it is seen in the neck too.
How sciatica feels
Sciatica is pain that travels along the sciatic nerve, from the buttock down the back of the thigh and leg, sometimes to the foot. It is usually on one side and can feel sharp, burning or like an electric shock, often with tingling or numbness. It tends to be worse on sitting, bending or coughing, and the leg pain can be stronger than the back pain.
Sciatica is a symptom, not a diagnosis. A slipped disc is the commonest cause, but narrowing of the spinal canal and a slipped vertebra can also cause it. Back pain alone, without pain below the knee or any tingling, is usually not sciatica.
Treatment without surgery
For most people the plan, after an examination, looks like this:
- Stay as active as comfort allows. Short rests are fine, but long bed rest slows recovery.
- Pain-relieving medicines taken as advised by the doctor.
- Physiotherapy for the back, hips and core, with advice on posture and lifting.
Most slipped disc and sciatica pain improves over several weeks, and the time varies from person to person. An MRI is used when symptoms are severe or not settling, or when surgery or an injection is being considered.
Nerve root blocks
When leg pain is severe, or keeps exercises from progressing, a selective nerve root block in the lower back (also called a lumbar foraminal block) may be considered. Using X-ray guidance, a thin needle is placed where the irritated nerve leaves the lumbar spine, and medicine is placed next to the nerve. It helps confirm which nerve is the source of the pain and in some people gives relief for a period, so that rehabilitation can go on. It does not repair the disc.
Many people never need an injection. Possible effects include soreness and, rarely, infection, bleeding or nerve irritation. Very rarely, a blood vessel or nerve can be injured. Some of the medicines used can raise blood sugar for a few days, so tell the doctor if you have diabetes.
When is surgery considered?
- Severe leg pain that has not improved after a proper trial of non-surgical care, usually about six weeks, with an MRI that matches the symptoms.
- Weakness in the leg or foot that is getting worse, or a foot that drops.
- Signs of pressure on the nerves at the base of the spine (see the warning signs below), which need same-day emergency assessment and urgent surgery.
For sciatica without weakness, about six weeks of non-surgical care usually comes first before surgery is discussed. The usual operation is a discectomy or microdiscectomy, in which the part of the disc pressing on the nerve is removed through a small cut at the back. It mainly relieves leg pain; back pain is less predictable. Risks and alternatives are explained first. Read more on slip disc surgery, or decompression and fusion for a narrowed canal.
Warning signs that need urgent care
Go to a hospital emergency department the same day, without waiting for an OPD visit, for:
- Loss of control of urine or stool, or being unable to pass urine.
- Numbness around the genitals, anus or inner thighs, pain or numbness in both legs, or a new change in sexual function.
- Leg weakness that is getting worse.
- Back pain after a fall or accident, or severe back pain with fever.
See a doctor within a day or two for back pain with unexplained weight loss or a past history of cancer.
When to see a doctor
Book an OPD visit if leg pain has not improved after a few weeks, or sooner if there is any weakness. Bring any MRI or X-ray you have.