Low Back pain is an extremely common human phenomenon, a price mankind has to pay for their upright posture. According to one study, almost 80 per cent of persons in modern industrial society will experience back pain at some time during their life.
Fortunately, in 70 per cent of these, it subsides within a month. But, in as many as 70 per cent of these (in whom pain had subsided), the pain recurs.
Causes of Low back pain
The specific etiology of most back pains is not clear. Postural and traumatic back pains are among the commonest.
Back pain could be a feature of an extra-spinal disease like a genitourinary or gynecological disease. The following findings in the clinical examination are helpful in reaching a diagnosis.
Seronegative spond-arthritis (SSA)
– Osteoid osteoma
– Eosinophilic granuloma
-Primary: Multiple myeloma, Lymphoma – Secondaries from other sites
Pain referred from viscera
Functional back pain
Postural back pain
– Protuberant abdomen
Occupational bad posture
– Habitual bad posture
Age: Some diseases are commoner at a particular age. Back pain is uncommon in children, but if present, it is often due to some organic disease. This is different from adults, in whom psycho logical factors play an important role in producing back pain. In adolescents, postural and traumatic back pain are commoner.
In adults, ankylosing spondylitis and disc prolapse are common. In elderly persons, degenerative arthritis, osteoporosis and metastatic bone disease are usually the cause.
Sex: Back pain is commoner in women who have had several pregnancies. Lack of exercise leading to poor muscle tone, and nutritional osteomalacia are contributory factors in these patients. Some women put on a lot of weight during pregnancy, and later develop mechanical back pain.
Occupation: A history regarding the patient’s occupation may provide valuable clues to risk factors responsible for back pain. These are often not apparent to the patient, and could be a part of his ‘routine’. People in sedentary jobs are more vulnerable to back pain than those whose work involves varied activities. Back pain is common in surgeons, dentists, miners, truck drivers etc.
Past history: A past history of having suffered from spinal disease such as a traumatic or inflammatory disease may point to that as the possible cause of back pain.
Features of pain:
The following features are to noted:
Location: Pain may be located in the lower, middle or upper back. Disc prolapse and degenerative spondylitis occur in the lower lumbar spine; infection and trauma occur in the dorso-lumbar spine
Onset: Often, there is a history of significant trauma immediately preceding an episode of back pain, and may indicate a traumatic pathology such as a fracture, ligament sprain, muscle strain etc. A precipitating history is present in about 40 per cent cases of disc prolapse. The trauma may not particularly bea significant one.
It may be subtle, resulting from a routine activity such as twisting to pull something out of a drawer. Careful questioning regarding leisure activities and exercise is important because inconsistency in activity levels during work and leisure time can precipitate back pain.
Localisation of pain: Pain arising from a tendon or muscle injury is localised, whereas that i originating from deeper structure is diffuse. Often, pain referred to a dermatome of the lower limb, with associated neurological signs. pertaining to a particular root, points to nerve root entrapment.
Progress of the pain: In traumatic conditions, or in acute disc prolapse, pain is maximum at the onset, and then gradually. subsides over days or weeks. Back pain due to disc prolapse often has periods of remissions and exacerbation. An arthritic or spondylitic pain is more constant, and is aggravated by activity. Pain due to infection or tumour takes a progressive course, with nothing causing relief
Relieving and aggravating factors: Most back pains are worsened by activity and relieved by rest. Pain due to ankylosing spondylitis, and seronegative spond-arthritis (SSA) is typically worse after rest, and improves with activity. Severe back pain at night that responds to aspirin may indicate a benign tumour. Pain initiated on walking or standing and relieved by rest, is a feature of spinal stenosis. An increase in pain during menstruation may indicate al gynaecological pathology.
Associated symptoms: The following associated symptoms may point to the cause of back pai
Stiffness: It is associated with most painful backs, but it is a prominent symptom in pain due to ankylosing spondylitis, more so early in the morning. There may be an associated limitation of chest expansion.
Pain in other joints: In some rheumatic diseases, back pain may be the presenting feature, but on detailed questioning one may get a history of pain and swelling of other joints.
Neurological symptoms: Symptoms like paraesthesias, numbness or weakness may point to a lesion of the nervous tissue, or a lesion in close proximity to it (e.g., a disc prolapse).
Extra-skeletal symptoms: A history suggestive of abdominal complaints, urogenital complaints, or gynecological complaints may indicate an extra-skeletal cause of back pain.
Mental status of the patient must be judged to rule out any psychological cause of back pain (hysteria, malingering, etc.). A patient suffering from an organic disease may have an significant underlying psychological disturbance also.
posture and low back pain
The patient should be stripped except undergarments, and examined in the standing and lying down positions:
Standing position: The following observations are made in the standing position:
Position: Normally a person stands erect with the centre of the occiput in the line with the natal cleft , the two shoulders are at the same level, the lumbar hollows are symmetrical and the pelvis is ‘square’. In a case with back pain, look for scoliosis, kyphosis, lordosis, pelvic tilt and forward flexion of the torso on the lower limbs.
Spasm: Muscle spasm may be present in acute back pain and can be discerned by the prominence of the para-vertebral muscles at rest, which stand out on slightest movement.
Tenderness: Localised tenderness may indicate ligament or muscle tear. There may be trigger points or tender nodules in cases of fibrositis (see page 304). Pain originating from the sacroiliac joint may have tenderness localised to the posterior superior iliac spine.
Swelling: A cold abscess may be indicating tuberculosis as the cause.
Range of movement: There is limitation of movement in organic diseases of the spine. One must carefully differentiate spinal movements from the patient’s ability to bend at the hips.
Lying down position: In the supine position the following observations are made.
Straight leg raising test (SLRT): This is a test to detect nerve root compression (Annexure-III).
Neurological examination: Sensation, motor power and reflexes of the lower limb a examined. This helps in localising the site of spine pathology.
Peripheral pulses: The peripheral pulses should be palpated to detect a vascular cause of low back pain, which may be due to vascular claudication.
The skin temperature in the affected leg may be lower.
Adjacent joints: Often, the pain originates from the hip joints or the sacro-iliac joints, hence the should be examined routinely.
Abdominal, rectal or per vaginal examination may be done wherever necessary. Chest expan sion should be measured in young adults with back pain.
The diagnosis of back pain is essentially clinical. There is no use getting X-rays done in acute back pain less than 3 weeks duration, as it does not affect the treatment. On the contrary, X-ray examination is a must for back pain lasting more than 3 weeks; it is almost an extension of the clinical examination.
There are a number of other investigations like CT scan, MRI scan, bone scan, blood investigations etc. One has to be very thoughtful in ordering these investigations. Order only when you think it is going to change your line of action, or if the clinical diagnosis is doubtful.
Radiological examination: Routine X-rays of the lumbosacral spine (AP and lateral) and pelvis (AP) should be done in all cases. These are useful in diagnosing metabolic, inflammatory and neoplastic conditions. Though, X-rays are usually normal in non-specific back pain, these provide a base line. X-rays should be done after preparation of the bowel with laxatives and charcoal tablets.
CT scan has replaced more invasive techniques like myelography etc. It shows most bony and soft tissue problems around the spine and spinal canal.
MRI scan is an expensive investigation, now available in big cities. It delineates soft tissues extremely well, and may be needed in some cases.
Blood investigations: These should be carried out if one suspects malignancy, metabolic disorders, or chronic infection (please refer to their respective Chapters for details).
Electromyography: If nerve root compression is possibility, electromyography (EMG) may be appropriate.
Bone scan: It may be helpful if a benign or malignant bone tumour is suspected on clinical examinations but is not seen on plain X-rays.
Principles of treatment: For specific pathologies,
treatment is discussed in respective chapters. Most back pains falling in the ‘non-specific’ category have a set programme of treatment, mostly conservative. It consists of rest, drugs, hot packs, spinal exercises, traction, corset and education regarding the prevention of back pain.
Rest: In the acute phase, absolute bed rest on a hard bed (a mattress is allowed) is advised. Bed rest for more than 2-3 weeks is of no use; rather, a gradual mobilisation using aids like brace is preferred.
Drugs: Mainly analgesic-anti-inflammatory drugs are required. In cases with a stiff spine, muscle relaxants are advised.
Physiotherapy: This consists of heat therapy (hot packs, short-wave diathermy, ultrasonic wave etc.). Gradually, a spinal exercises programme is started.
Traction: It is given to a patient with back pain with lot of muscle spasm. It also sometimes help in ‘forcing’ the patient to rest in the bed.
Use of corset: This is used as a temporary measure in treating acute back pain, in back pain due to lumbar spondylosis, etc.
Education: Patients must be taught what they can do to alleviate the pain and to avoid injury or re-injury to the back. This includes education to avoid straining the back in activities of daily living such as sitting, standing, lifting weight etc. ‘Back Schools’ are formalised approach to this education.
MAJOR CAUSES OF LOW BACK PAIN
Spina bifida: This and other minor congenital anomalies of the spine are present in about half the population, but are not necessarily the cause of back pain. Therefore, other pathological conditions should be ruled out before diagnosing this as the cause of symptoms. Treatment is as for non-specific back pain.
Transitional vertebrae: A transitional vertebra is the one at the junction of two segments of the spine, so that the characteristics of both segments is present in one vertebra. It is common in the lumbosacral region, either as lumbarisation (S, becoming L) or sacralisation (L, fused with the sacrum, either completely or partially).
Back strain (acute or chronic): The terms back strain and back sprain are often used interchangeably. Most often this arises from a ‘trauma’ sustained in daily routine activities rather than from a definite injury.
People prone to back strain are athletes, tall and thin people, those in a job requiring standing for long hours and those working in bad postures. Sedentary workers and women after pregnancy are also frequent candidates for back strain.
Acute ligament sprain may occur while lifting a heavy weight, sudden straightening from bent position, pushing etc. Treatment is ‘non-specific as discussed earlier.
Compression fractures: These fractures occur commonly in the thoraco-lumbar region. Treatment depends upon the severity of compression. It is important to be suspicious of any underlying pathology. Diseases such as early secondary deposits in an elderly, may produce a fracture spontaneously, in one or multiple vertebrae.
Tuberculosis: Spinal tuberculosis is a common cause of persistent back pain, especially in undernourished people living in unhygienic conditions. Early diagnosis and treatment is crucial for complete recovery.
Ankylosing spondylitis: This should be suspected in a young male presenting with back pain and stiffness. Symptoms are worst in the morning and are relieved on walking about. Spinal movements may be markedly limited along with limitation of chest expansion.
Spinal stenosis: Narrowing of the spinal canal may occur in the whole of the lumbar spine (e.g., achondroplasia), or more often, in a segment of the spine (commonly in the lumbo-sacral region). Stenosis may be in all parts of the canal or only in the lateral part; the latter is called as root canal stenosis. It may give rise to pressure or tension on the nerves of the cauda equina or lumbar nerve roots. Typically, the patient complains of pain radiating down the lower limbs on walking some distance, and is relieved on taking rest for a few minutes (neurological claudication). Diagnosis is confirmed by a CT scan or MRI. Treatment is by decompression of the spinal canal or root canal, as the case may be.
Both benign and malignant tumours occur in the spine and the spinal canal. Tumours of the spinal canal, usually benign, are classified as extradural or intradural; the latter can be either intra-medullary or extra-medullary.
These tumours are usually diagnosed on myelogram or CT scan. Tumurs of the spine are mostly malignant, usually secolaries from some other primary tumours. Some commoner tumours of the spire as discussed below.
Benign tumours: These are uncommon. Osteoid osteoma is the commonest benign tumour of the spine. It causes severe back pain, especially at night. Typically the pain is relieved by aspirin. The tumour, usually the size of a pea, is found in the pedicle or lamina.
Haemangioma also occurs in the vertebral body. Meningioma is a common intradural, extra-medullary tumour which presents with back pain or radiating pain.
Malignant tumours: Multiple myeloma is the commonest primary malignancy of the spine. Metastatic deposits are extremely common in the spine because of its rich venous connections, especially with the vertebral venous plexus.
Pain often precedes X-ray evidence of a metastatic deposit. By the time a deposit is visible on X-ray, the tumour has replaced about 30 per cent of the bony content of the vertebra. A bone scan can detect the lesion earlier.
Metabolic disorders: Osteoporosis and osteomalacia are common causes of back pain.
degenerative Facet arthropathy and subtle Arthritis of the facet joints can result from a disease and mal-development of the facets (facet tropism).
The source of back pain is difficult to find because of variable factors. The aim is to identify the pathology that needs immediate treatment, such as an infection, neoplasm, disc prolapse etc. All other back pain are treated as ‘non-specific back pain’ with more or less common treatment programme.
While the patient is on this treatment programme, he is reviewed at regular intervals for any additional signs suggesting an organic illness. First establish whether the problem is acute (3 to 6 months) or chronic (longer than 6 months). If it is an acute pain, whether it is related to a definite episode of trauma or is spontaneous in onset.
The causes are accordingly worked out. In cases with chronic back pain, it is helpful to judge whether it is mechanical or inflammatory by asking the patient whether rest bring relief or makes the pain worse. According further sign s and symptoms helping diagnosis. Gives an outline of how to approach a patient with low back pain.