One useful system of classification that has been validated was first proposed by Fairbank and Hall (Fairbank, 2002). It is outlined below:
Attacks occur acutely, with or without obvious precipitating events. Precipitating events may be relatively minor and it is not always helpful to dwell too much on this aspect of the history. The patient's view of what led to the pain may be subjective and is often related to occupational factors although in practice sport, DIY or other home factors are frequent causes of acute low back pain.
The pain is generally limited to the lumbar spine and adjacent muscles. There may be some pain referral to buttocks and the back of the thighs, but pain is not felt below the knee. Many patients will describe their symptoms as 'sciatica' but this is not a useful descriptive term for referred pain that is classically confined largely to the lower back with radiation limited to above the knee. Pain tends to be worse when sitting and improves with activity.
Although these attacks are self-limiting they may be recurrent. This does not imply an underlying defect or problem even though individuals may state they have a 'weak back' or a 'bad back'.
There is no clear distinction between acute, simple back pain, and chronic back pain. Those with chronic pain tend to have persistent underlying pain or discomfort with occasional acute exacerbations. Some of these individuals have definitive signs from imaging tests that demonstrate degenerative disease within the lumbar spine, although most individuals with signs of degeneration of the spine in imaging tests are asymptomatic.
The distribution of pain is similar to that of simple back pain, predominantly in the lower back with some buttock and thigh radiation. Referred pain classically varies in distribution with intensity, being felt further down the leg the more severe the pain ('thermometer pain'). This history helps distinguish referred pain from root pain.
It is not helpful to regard chronic back pain as a purely physical ailment. It is best considered in terms of a biopsychosocial model as described by Waddell, with complex interactions between physical symptoms, mood, and illness behaviour (Waddell, 1992). The relevance of all three is very important in determining long-term prognosis.
As people age they may develop a number of psychological issues with shift work, family commitments, having to accept that they are less physically able as they become older, and having to cope with the normal musculoskeletal aging process. These issues may well reinforce the symptoms of low back pain and need to be considered as an integral part of the management of chronic back pain.
In these patients, the predominant symptom tends to be pain in the leg or legs with a dermatomal distribution. This is classic 'sciatica'.
|
Nerve root |
Location of symptoms |
|
S1 |
Posterior calf and lateral side and sole of foot |
|
L5 |
Lateral calf and dorsum of foot |
|
L4 |
Medial calf |
|
L3 |
Anterior thigh just above knee |
There may initially be more back pain than leg pain, however in most cases after a few weeks or months the leg pain takes over as the most important symptom for the patient. It is not generally possible to distinguish between pain from lateral recess stenosis and pain from disc herniation on clinical assessment although a careful history may differentiate between them.
Pain must be distinguished from numbness which is a 'red flag' symptom. Clinicians should always ask about saddle numbness and incontinence to exclude cauda equina syndrome which is a surgical emergency. Root pain may co-exist with referred pain, while in many cases root pain is felt in isolation with no back pain. Many of the psychosocial issues described above under chronic low back pain are just as relevant to nerve root pain.
In these patients, the leg pain is provoked by standing or walking, and resolves when they sit or lie down. The underlying condition of spinal stenosis may require nerve root blocks or surgery to relieve symptoms, but a third of patients will improve spontaneously.
Where the spinal cord is directly involved and compromised, patients may have symptoms of myelopathy. Lumbar spondylosis is unlikely to cause cord pathology because the cord generally ends above this region, so most patients with myelopathy have cervical spondylosis. Some have thoracic spondylosis. Symptoms can include pain, more generalised numbness and weakness, and classically patients have ‘clumsy hands’.
Where symptoms are unusual, are not relieved by postural change or include rest pain or pain at night, these individuals may have a tumour or infection, an isolated fracture secondary to osteoporosis or steroid use, or psychogenic pain. This group includes a number of 'red flag' signs and symptoms as well as most 'yellow flag' symptoms.
FAIRBANK, J. 2002. Clinical presentations of the Lumbar Spine. In: BULSTRODE, C., BOWDEN, G., BUCKWALTER, J., CARR, A., FAIRBANK, J., MARSH, L. & WILSON-MACDONALD, J. (eds.) The Oxford Textbook of Orthopaedics and Trauma. Oxford: Oxford University Press.
WADDELL, G. 1992. Biopsychosocial analysis of low back pain. Baillieres Clin Rheumatol, 6, 523-57.