Mechanical Low Back Pain (LBP)
Scope of this article:
This article focuses on mechanical (non-specific) low back pain , without lubosacral radiculopathy (i.e. not sciatica). For sciatica and radiculopathy, see the Sciatica and Lumbosacral Radiculopathy article.
Disclaimer:
Mechanical (non-specific) low back pain and sciatica (lumbosacral radiculopathy) are distinct clinical conditions, but they may coexist in the same patient.
It is important to distinguish between these conditions in exams. However, in clinical practice (esp. in non-specialist setting), the exact distinction is less important. The priority is to identify red flags that may suggest an underlying serious condition. In the absence of red flags, both conditions share the same management approach.
Causes and Risk Factors
Common contributing factors and triggers:
- Muscle or ligament strain (e.g. from heavy lifting, twisting, overexertion)
- Paraspinal muscle spasm
- Age-related degenerative changes (e.g. facet joint diseas, intervertebral disc degeneration)
Risk factors for non-specific low back pain:
- Obesity
- Physical inactivity
- Occupational factors (e.g. those that require heavy lifting, bending, twisting)
- Stressful life events
- Depression
Clinical Features
Mechanical / non-specific low back pain typically presents with:
- Onset after a mechanical trigger (e.g. heavy lifting)
- Pain localised to the lower back
- Sometimes radiating to the buttocks or upper thigh that is not in a clear dermatomal pattern
- Presence of pain / sensory changes in a clear dermatomal pattern should raise suspicion of sciatica / radiculopathy
- Characteristic features (that distinguish from back pain secondary to a serious underlying cause)
- Pain worsened by movement (e.g. bending, lifting, twisting, certain postures)
- Pain relieved by resting (e.g. lying down)
- Paraspinal muscle tenderness (but not mid-line tenderness)
- Absence of objective neurological deficit (e.g. weakness, reduced reflexes)
Back Pain Red Flags
| Serious underlying condition to exclude | Key red flags |
|---|---|
| Cauda equina syndrome |
|
| Spinal fracture |
|
| Cancer |
|
| Infection (e.g. discitis, vertebral osteomyelitis, spinal / epidural abscess) |
|
TUNA FISH is a mnemonic / clinical screening tool used for low back pain red flags:
- T: trauma
- U: unexplained weight loss
- N: neurological symptoms (esp. saddle anaesthesia, loss of bowel or bladder control)
- A: age (<20 or >50 y/o carries a higher risk of serious non-mechanical causes)
- F: fever
- I: IVDU
- S: steroid use
- H: history of cancer
Investigation and Diagnosis
Clinical diagnosis (based on clinical history and physical examination)
Consider using the STarT Back risk assessment tool for risk assessment and stratification to guide management
DO NOT routinely offer imaging (including lumbar X-rays and MRI) in a non-specialist setting
Only consider imaging in a specialist setting if the result is likely to change management
Management
First, exclude red flags that may suggest a serious underlying cause
- If cauda equina syndrome or spinal fracture is suspected → emergency referral to a spinal surgery service
- If cancer or infection is suspected → urgent referral to a spinal surgery service or urgent MRI within 2 weeks
Choice of management based on risk stratification:
- Likely to have a good outcome (e.g. low risk of chronicity on STarT Back) → simpler and less intensive support (e.g. reassurance + advice to keep active + guidance on self-management)
- Higher risk of a poor outcome (e.g. high risk of chronicity on STarT Back) → more complex and intensive support (e.g. exercise programmes +/- manual therapy or psychological approach)
Conservative / General Management
Advise to:
- Stay active and continue normal activities as much as possible
- Perform exercises that promote strength, flexibility and aerobic fitness
Offer:
- Structured exercise programme
- +/- Manual therapy (e.g. spinal manipulation, mobilisation or massage)
- +/- Psychological therapies using a CBT approach
Do NOT offer the following:
-
Belts, corsets, foot orthotics, and shoes
-
Manual traction therapy
-
Acupuncture
-
Electrotherapies (including: ultrasound, TENS, PENS, interferential therapy)
Pharmacological Management
- 1st line: oral NSAIDs (use the lowest effective dose for the shortest possible period of time)
- 2nd line: weak opioid +/- paracetamol
Do NOT offer paracetamol alone
Do NOT offer the following:
- Gabapentinoids (pregabalin and gabapentin) and other antiepileptics
- Benzodiazepines
- Corticosteroids
- Opioids
- SSRIs, SNRIs, TCAs
Interventional / Invasive Management
Interventional / invasive management is primarily for sciatica (i.e. lumbosacral radiculopathy), but not simply low back pain without evidence of radiculopathy.
See the Sciatica and Lumbosacral Radiculopathy for more information.