How common is lower back pain?

Lower back pain is very common. The majority of people will experience lower back pain at some stage.

Lower back pain is usually self-limiting, and the vast majority of individuals improve with simple treatment measures or without any treatment at all.

There are numerous causes for back pain, but fortunately most are not serious.

What can cause lower back pain?
A number of structures in the back may be responsible for back pain. Back pain is also known as ‘lumbago’, named after the lumbar region of the spine.

To understand how back pain may arise, it is necessary to have a basic understanding of spinal anatomy in the lumbar region.

The lower back is called the lumbar spine and is made up of five vertebrae (spinal bones) and the sacrum (part of the pelvis).

The lumbar spine is made up of a number of spinal (or ‘motion’) segments. Each spinal segment includes:

• Two vertebrae (spinal bones)
• An intervertebral disc between the two vertebrae (contains a central nucleus, and an outer annulus)
• One nerve root that leaving the spinal canal on each side
• One nerve root passing over the disc and down to the next segment on each side
• Two facet joints at the back, which link the two vertebrae
• Muscular attachments and ligaments
  

Lower back pain may be categorized as either mechanical or compressive.

Mechanical lower back pain results from inflammation as a consequence of irritation or injury to the:

• Intervertebral disc (annular tear, disc degeneration, or disc prolapse)
• Facet joints
• Ligaments or the muscles of the back (musculoligamentous back pain)
• or as a result of spondylolisthesis (a slip of one vertebra on another).

Less common, but extremely important, causes of mechanical lower back pain include:

• Traumatic fractures and/or dislocations
• Tumours which have spread to the spine (metastases)
• Infection (discitis, osteomyelitis, epidural abscess)

Mechanical pain usually starts in or near the midline, and may spread (radiate) to the buttocks and thighs. It is unusual for this type of pain to extend below the knee. Sometimes hip problems (for example, osteoarthritis) may imitate mechanical lower back pain.

Compressive lower back pain arises when one or more nerve roots are either irritated or pinched. A prolapsed (herniated) intervertebral disc is a common cause of compressive pain.

Compressive back pain is frequently associated with pain extending down the leg (sciatica) and sometimes into the foot. This leg pain may be associated with numbness or weakness.

How is lower back pain treated?
Treatment for lower back pain is usually non-operative, and surgery is only necessary in a small percentage of patients.

Your specialist may prescribe modification of physical activities, including avoidance of certain recreational and work-related activities, to help settle symptoms from mechanical back pain. Special braces are occasionally prescribed to ease back pain. Strict bed rest is rarely needed, however short periods of bed rest may help with acute painful episodes.

A well-rounded physical rehabilitation program assists in settling pain and inflammation, improving mobility and strength, and helping you to do your daily activities more easily. A combination of physiotherapy, hydrotherapy and clinical pilates is usually recommended.

Positions, movements, and exercises are prescribed to reduce pain. Hamstring flexibility is addressed, along with strength and coordination exercises for the low back and abdominal muscles (core stability exercises).

The aims of these physical therapies are to assist you in

• managing your condition and controlling your symptoms
• correcting your posture and body movements to reduce back strain
• improving your flexibility and core strength

Some patients also benefit from chiropractic treatment osteopathy, remedial massage, and acupuncture.

Review by a clinical psychologist is often useful. Strategies to manage pain may include cognitive behavioural therapy and mindfulness-based programs. It is important to treat any associated depression or anxiety, as these conditions may increase your experience of pain.

Medications play an important role in controlling pain, easing muscle spasms, and helping to regain a normal sleep pattern. Long-term medication usage should not be undertaken lightly, and should be closely supervised in order to avoid problems such as tolerance and dependence (addiction).

Epidural steroid injections, facet joint blocks and radiofrequency denervations, and nerve sheath injections may yield a benefit.

Surgery is needed only if conservative treatments fail to keep your pain at a tolerable level, and when the underlying condition is amenable to surgery. Not all patients with severe unremitting back pain are suitable for surgery. Surgical treatment must address any mechanical (instability) and compressive (nerve pressure) issues.

Nerve pressure generally requires surgical decompression, also known as a decompressive laminectomy. In order to deal with the compressive issues by taking pressure off the nerves, your surgeon may need to remove a significant amount of bone. The facet joints in particular normally provide stability in the lumbar spine. Removal of either or both can cause the spine to become loose and unstable, especially when a degree of slippage has already occurred. A fusion is therefore recommended in some patients.

Similarly, a fusion is necessary to adequately deal with the mechanical issues of instability when spondylolisthesis (slippage of one spinal bone on another).

Four types of fusion surgery are commonly recommended for the treatment of back pain, depending upon individual patient factors:

1. Decompression and/or microdiscectomy (not usually recommended)
2. Transforaminal lumbar interbody fusion (TLIF)
3. Posterior lumbar interbody fusion (PLIF)
4. Instrumented posterolateral fusion (pedicle screw fixation and posterolateral bone graft)
5. Anterior lumbar interbody fusion (carried out through the abdomen, rather than from the back)
6. Artificial disc replacement or nucleus replacement