Non Specific Low Back Pain


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Definition

Non-specific (or Simple or Mechanical) low back pain is the general term that refers to any type of back pain in the lumbar region that is not related to serious pathology and/or does not have a specific cause. 

Non-specific low back pain is usually categorized in 3 subtypes: acute, sub-acute and chronic low back pain. This subdivision is based on the duration of the back pain. Acute low back pain is an episode of low back pain for less than 6 weeks, sub-acute low back pain between 6 and 12 weeks and chronic low back pain for 12 weeks or more.

Epidemiology/etiology

Low back pain (LBP) is the fifth most common reason for physician visits, which affects nearly 60-80% of people throughout their lifetime. The lifetime prevalence of low back pain is reported to be as high as 84%, and the prevalence of chronic low back pain is about 23%, with 11-12% of the population being disabled by low back pain.  Economically LBP is a huge burden, the cost of care for LBP has been reported (in the USA) to be over $50 billion annually.  It should be noted that most of the epidemiology studies have been done in the western industrialised higher resourced countries so these figures will differ globally. 

Despite the intense focus and formal research on the care of non-specific LBP Pransky et al reported a five fold increase in the prevelance of LBP over a 15 year period.  

Low back pain is a self limiting condition:

• 90% of people with LBP will recover in 3-4 months with no treatment.
• 70% of people with LBP will recover in 1 month with no treatment.
• 50% of people with LBP will recover in 2 weeks with no treatment.
• 5% of the remaining 10% will not respond to conservative care (such as physiotherapy)
  
• The final 5% are the more challenging cases that don't naturally improve that we as physiotherapists commonly see.

However these figures may be deceptive because although the pain may go away the the reoccurrence rate of LBP is extremely high  and these individuals are likely to experience another episode of LBP within 3-6 months.  Reoccurrence is a major problem with the reoccurrence rate being approximately 60%.

Non-specific low back pain accounts for over 90% of patients presenting to primary care and these are the majority of the individuals with low back pain that present to physiotherapy.

Non-specific low back pain can caused by:

• Traumatic injury
  
• Lumbar sprain or strain
  
• Postural strain

Or can be secondary to condiions such as:

• Spondylolysis and Spondylolisthesis
  
• Disc Herniaton
  
• Spinal Stenosis
  
• Osteoporosis with Compression fracture (Lumbar compression fracture)
  
• Congenital disease such as Kyphosis and Scoliosis
  

Cook et al (study ongoing 2015) studied risk factors for LBP pain: 

	First occurrence	Recurrent episode
Community setting	standing or walking >2hrs per day frequent moving or lifting >25 lbs widespread pain limping higher general health scores	other musculoskeletal compliants sitting, standing or walking >2hrs per day frequent moving or lifting >25 lbs strength <50% depression perceived inadequacy i.e. income, job
Occupational setting	female obesity increased driving time perceived heavy lifting requirements slower velocity doing activities poor MCS SF-12 score (i.e. higher anxiety, depression etc)	obesity poor health prior LBP poor back endurance frequent moving or lifting >25 lbs manual jobs awkward posture mental distress poor relationships at work

Leg pain is a frequent accompaniment to low back pain, arising from disorders of neural or musculoskeletal structures of the lumbar spine. Differentiating between different sources of radiating leg pain is important to make an appropriate diagnosis and identify the underlying pathology.  Some specific causes of leg pain need to be managed in a different way to simple non-specific low back pain.

Possible Mechanisms

Any innervated structure in the lumbar spine can cause symptoms of low back and referred pain into the extremity or extremities. This long list of potential structures includes the muscles, ligaments, dura mater and nerve roots, zygapophyseal joints, annulus fibrosis, thoracolumbar fascia, and vertebrae.  One might expect that improvement in the resolution of imaging technology has increased the likelihood of detecting a link between pathology and pain in the lumbar spine. However, the determination of a pathoanatomic origin of low back pain is made difficult by the rate of false-positive findings on imaging studies, that is, individuals without low back pain showing abnormal findings. For example, evidence of herniated disc material is shown on computerized tomography (CT) scans, MRI, and myelography in 20% to 76% of persons with no sciatica. Furthermore, Savage et al reported that 32% of their asymptomatic subjects had “abnormal” lumbar spines (evidence of disc degeneration, disc bulging or protrusion, facet hypertrophy, or nerve root compression) and only 47% of their subjects who were experiencing low back pain had an abnormality identified. In longitudinal studies, low back pain can develop in the absence of any associated change in radiographic appearance of the spine. Boos et al followed asymptomatic patients with a herniated disc for 5 years and determined that physical job characteristics and psychological aspects of work were more powerful than MRI-identified disc abnormalities in predicting the need for low back pain–related medical consultation. Thus, the association between clinical complaints and concurrent pathological examination with radiological findings must be considered cautiously. Further, even when abnormalities are present, establishing a direct cause and effect between the pathological finding and the patient condition has proven to be elusive and most often does not assist greatly in patient management.

Physiotherapy assessment aims to identify impairments that may have contributed to the onset of the pain, or increase the likelihood of developing persistent pain. These include biological factors (eg. weakness, stiffness), psychological factors (eg. depression, fear of movement and catastrophisation) and social factors (eg. work environment). The assessment does not focus on identifying anatomical structures (eg. the intervertebral disc) as the source of pain, as might be the case in peripheral joints such as the knee. Previous research and international guidelines suggest it is not possible or necessary to identify the specific tissue source of pain for the effective management of mechanical back pain.

Characteristics/clinical presentation

 

This low back pain is usually aggravated by:

• Long levered activities
• Lifting heavy objects
• Levered postures (bending forward)
• Static loading of the spine (prolonged sitting or standing)

Diagnostic procedures

Once serious spinal pathology and specific causes of back pain have been ruled out the patient is classified as having non-specific low back pain. As mentioned above it is not necessary to determine the specific pain causing structure to effectively manage this patient group.

Differential diagnoses

• Discogenic back pain 
  
• Cauda Equina Syndrome
  
• Fracture (compression, spinosus process, stress fractures of pars)
  
• SI dysfunction
  
• Non-back pain infection (AAA, Pancreatitis, posterior penetrating ulcer and pyelonephritis)
  
• Metastatic disease (prostate, renal cell, thyroid, breast)
  

Examination

See Lumbar Examination

Medical management

Mechanical low back pain (LBP) is not a life-threatening illness. Unfortunately, it does have a far-reaching impact on medical care expenditures for injured workers.

Pharmacological interventions for the relief of low back pain (LBP) include acetaminophen, nonsteroidal anti-inflammatory drugs (NSAIDs), topical analgesics, muscle relaxants, opioids, corticosteroids, antidepressants, and anticonvulsants.

Acetaminophen remains one of the best first-line treatments of acute LBP.

Physical therapy management

The conservative treatment in the initial phase is ice massage followed by passive knee-to-chest stretch (one leg at a time then both legs together). Also daily walks followed by stretching, electrical stimulation and iontophoresis are recommended in this phase. It’s important to identify possible causes and to correct harmful activities and attitudes, to avoid further back pain problems.

In the second phase it’s necessary to continue the pain management and to be alert for ‘red flags’. The rehabilitation program exists out of stretching of the hamstrings and back (knee-chest), strengthening of back flexors and extensors and core strengthening.

Patients should be taught several correct and comfortable positions and postures (during sleeping, sitting, lying, standing, walking and lifting techniques) that are safe for the spinal structures.

Resources

http://www.allaboutbackandneckpain.com/recognizingsymptoms/causesoflowbackpain.asp

http://www.fmcpaware.org/m-n/mechanical-low-back-pain