What Causes Lower Back Pain?
Researchers and spinal health care practitioners categorise lower back bain into the following categories:
1. Specific Spinal Pathologies (<1%)
2. Radicular Syndromes (5-10%)
3. Non-Specific Lower Back Pain (NSLBP) (Bardin et al., 2017)
Specific Spinal Pathologies
Some conditions that cause back pain do require an urgent and specific referral and treatment. These conditions include:
- spinal infections
- cancer (malignancy)
- spinal arthropathies (e.g. rheumatoid arthritis or ankylosing spondylitis)
- cauda equina syndrome
- spinal fractures.
These conditions do require early diagnosis and prompt referral to the appropriate medical specialist. Luckily these conditions account for less than 1% of back pain sufferers, but you don’t want them missed.
Some referrals should be IMMEDIATE!
Lower back pain can result from structural damage that can irritate or pinch a nerve. Researchers believe that radicular syndrome causes 5-10% of back pain presentations to general practitioners.
Radicular pain (e.g. sciatica)
The most common pinched nerve in the lower back is your sciatic nerve. You may be diagnosed with sciatica if you are suffering radicular pain down your leg due to a back injury. While the sciatic nerve is the most common nerve that can be affected by a spinal injury, you can modify any spinal nerve function (e.g. femoral nerve).
The following back injuries may cause radicular pain:
- Herniated disc (slipped disc)
- Facet joint sprain
- Degenerative disc disease
- Back ligament sprain.
Pain is due to swelling or space-occupying material adjacent to the spinal nerve. The affected nerve may be irritated, resulting in radicular pain. Or, even worse, become pinched or compressed, resulting in radiculopathy.
Lumbar radiculopathy can result in functionally disabling conditions such as foot drop, foot slap or eversion muscle weakness that can affect your ability to walk.
Spinal stenosis is a slightly different condition and relates to the narrowing of the spinal canal. Spinal stenosis is usually more prevalent as you age.
Non-Specific Lower Back Pain (NSLBP)
Non-Specific Lower Back Pain (NSLBP) is the diagnostic term used to classify lower back pain sufferers with no specific structure injured. It is a diagnosis of exclusion. In other words, your spinal health care practitioner has excluded specific spinal pathologies and any of the radicular syndromes mentioned above as the cause of your back pain or symptoms.
Fortunately, these conditions account for approximately 90-95% of lower back pain and can nearly always successfully rehabilitate without the need for surgery. Most improve within two to six weeks. They can be fast-tracked with pain relief and physiotherapy techniques such as manual therapy and back exercises.
The causes of NSLBP are numerous but roughly fall into either a sudden (traumatic) or sustained overstress injuries.
Most people can relate to traumatic injury such as bending awkwardly to lift a heavy load that tears or damages structures. However, sustained overstress injuries (e.g. poor posture) are probably more common and more straightforward to prevent. In these cases, positional stress or postural fatigue creates an accumulated microtrauma that overloads your lower back structures over an extended period to cause injury and back pain.
Most commonly, NSLBP causes include back muscle strain or back ligament sprain. Other chronic back conditions such as degenerative disc disease may underly your acute disc health and predispose you to the severe pain.
The good news is that you can take measures to prevent or lessen most back pain episodes. Early diagnosis and specific individualised treatment are the easiest way to recover quickly from lower back pain and prevent a recurrence.