A slipped disc is when a soft cushion between the bones of the spine pushes out. The centre of the disc, called the nucleus, is soft, spongy and like a spring. This receives the shock of standing, walking and running etc. The structure covering the nucleus is called the annulus, which provides the structure and strength of the discs.
A slipped disc can occur in:
- Neck region
- Thoracic region (middle back) of the spine
- Lumbar (lower back) region of the spine
Epidemiology
Lower back pain has a point prevalence of 37% and a lifetime prevalence of 87%. Spinal disc herniation most commonly affects individuals aged 20-65 years and becomes more common among those between 45 and 55 years.
Aetiology and Risk factors
The spinal cord consists of an outer ring that is fibrous. In the middle of the disc, there is a substance called nucleus pulposus. A slipped disc occurs when the outer ring becomes weak and allows part of the softer inner portion to slip out.
There are several mechanisms by which a slipped disc can occur, including certain movements. When bending, twisting or turning, or lifting a heavy object, the heavy weight puts substantial strain on the lower back, which could cause a slipped disc. In obese patients, there is a higher risk of disc prolapse as the disc must support the additional weight.
Risk factors for a slipped disc are:
- Age
- Trauma
- Straining during exercise
- Incorrectly lifting weights or heavy objects: This commonly occurs when lifting with a bent waist, rather than lifting with the legs while the back is straight.
- Working with constantly vibrating machinery
- Sedentary lifestyle, and inactivity: As muscles that support the back and neck weaken from inactivity, this increases strain on the spine.
- Obesity: The deterioration of the spinal cord will accelerate as excess fat has to be supported.
- Tobacco: The chemicals found in cigarettes will interfere with the disc’s ability to absorb nutrients, which results in the weakening of the disc.
Clinical features
In some cases, a slipped disc does not produce any symptoms. When the disc bulges out, it may press on nearby structures such as a nerve coming from the spinal cord. The size of the slipped disc can vary. As a rule, the larger the prolapse, the more severe the symptoms are likely to be.
- Back pain: The pain is often severe and usually comes on suddenly. The pain is usually reduced by lying down flat and is often felt with movement of the back, coughing, or sneezing. If the nerve is involved, then the pain is felt as if it were traveling along the leg to the calf or foot.
- Difficulty straightening or bending back
- Numbness or tingling in the back, shoulders, arms, hands, legs, or feet
- Pain while walking a short distance
- If the prolapse is severe, it can lead to loss of functions including weakness of one or both legs and it may also affect control of urine and bowel.
- Muscle weakness
Diagnosis
A slipped disc is usually diagnosed by analysing the symptoms, your medical history, and a physical examination. A patient who presents with back and leg pain or neck and arm pain with associated weakness is suggestive of a slipped disc. In most cases, no further investigation is needed as the symptoms of slipped disc often subside within a few weeks. An MRI shows the site and size of a prolapsed disc.
However, other diseases of the spine – infections, tumours, and fractures – can also present with similar symptoms. An X-ray, CT scan, or MRI is performed to rule out other conditions. Electromyography and myelogram are used to detect any damage to the nerve.
Differential Diagnosis
There are many possible causes for unspecified back pain and neck pain, and there are many pathologies for this. Some differential diagnosis for the slipped disc are:
- Mechanical back pain
- Discal cyst: This is a mass in the inner disc that communicates with the intervertebral disc and causes pain that is resemblant to a slipped disc
- Epidural abscess
- Epidural hematoma
- Metastasis: Spread of cancer from another part of the body to bones of the spine
- Synovial cyst
Complications
The potential complications of a slipped disc are:
- Permanent neurologic dysfunction
- Chronic pain leading to depression, anxiety, substance abuse, and violence, etc.
- Cauda equina syndrome: It is a rare disorder and should be managed surgically as early as possible. In this condition, there is compression of the spinal nerve roots which may lead to the permanent paralysis of the legs.
Treatment
In most cases, the pain associated with a slipped disc improves over a few weeks. The bulging prolapsed disc tends to get smaller over time in most cases. In about 1 in 10 cases, the pain progresses further, causing surgery to be required. The goal of treatment is to rest and immobilise the spine, providing time for the soft tissue to heal. Some methods to treat slip disc are as follows:
Initially, you can help relieve the severe back pain caused by a slipped disc by:
- Taking bed rest on a firm mattress
- Alternating heat and ice application on the affected area
- Physical therapy: Gradually increasing daily activities as exercise will help increase muscle strength that is supporting the spine, thus reducing pain and shortening recovery time.
- Patient education on proper body mechanisms to prevent recurring injury
Medical treatments available for slip disc are:
- Drugs to reduce pain and swelling, such as ibuprofen and prednisolone
- Muscle relaxants to relax the back muscles
- Steroid injections into the slipped disc space
Surgical management: Surgical removal of the slipped disc may be necessary if the pain either worsens or fails to improve, or if there is a problem involving the nerve. It consists of discectomy, laminectomy, spinal fusion, etc.
Prevention
The only way to prevent a slipped disc is through lifestyle modifications, including staying active and exercising regularly. It might not always be possible to prevent a slipped disc, but some steps to reduce the risks are:
- Use proper lifting techniques while lifting heavy weights or ask for support
- Maintain a healthy weight
- Practice good posture while sitting down for long hours, such as while working
- Wear comfortable shoes
- Stretch your body if you haven’t moved for a long time
- Stop smoking
- Maintain a healthy diet
New treatments
Oxygen-ozone treatment for slipped discs is an emerging and potential treatment alternative to steroid injection and surgery. Oxygen-ozone gas is given through injection into the herniated disc, reducing the volume within the disc. When volume is reduced, the pressure on the nerve is also reduced. This, in turn, lowers the pain that is felt.
