WHAT Is lower back pain?
There are many causes for back pain. Fortunately, most are not serious.
Back pain is also known as ‘lumbago’, which takes its name from the lumbar region of the spine.
To understand how back pain may arise, it is necessary to have a basic understanding of the spinal anatomy in the lumbar region.
How common is lower back pain?
Lower back pain is very common. Up to 80% of people will experience lower back pain at some stage.
Lower back pain often resolves by itself, and most people find that their lower back pain improves with simple treatment or without any treatment at all.
Anatomy of the lower back
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 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 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 categorised as either mechanical or compressive.
Mechanical lower back pain results from inflammation. It is usually 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 mimic mechanical lower back pain.
Compressive lower back pain occurs 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 often associated with pain extending down the leg (sciatica) and sometimes into the foot. This leg pain may be associated with numbness or weakness.
Treatment for lower back problems
Treatment for lower back pain is usually non-operative. Surgery is only necessary in a small percentage of patients.
Change to physical activities
Your specialist may recommend that you change some of your physical activities, including avoiding certain recreational and work-related activities.
Special braces are sometimes prescribed as a way of easing back pain. Strict bed rest is usually not needed, however short periods of bed rest may help with severely painful episodes.
A well-rounded physical rehabilitation program can help to settle pain and inflammation and improve mobility and strength. This will help 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 lower 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 issues of depression or anxiety, as these conditions can 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 be helpful in some cases.
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) occurs.
Several types of surgery are recommended for the treatment of back pain:
- Anterior lumbar interbody fusion (ALIF) (carried out through the abdomen, rather than from the back)
- Artificial disc replacement or nucleus replacement
- Decompression and/or microdiscectomy (not usually recommended)
- Extracavitatory lateral interbody fusion (XLIF)
- Instrumented posterolateral fusion (pedicle screw fixation and posterolateral bone graft)
- Oblique lateral interbody fusion (OLIF)
- Posterior lumbar interbody fusion (PLIF)
- Transforaminal lumbar interbody fusion (TLIF)