core of bone and bone marrow. Research has shown that the pressure in the bone marrow of a joint affected by AVN is high. This increased pressure is thought to compromise the blood supply to the affected area of bone. Removing a core of tissue reduces the pressure and may improve the blood supply to the area of bone undergoing AVN. The efficacy of core decompression surgery to treat AVN of the hip has not been evaluated in rigorous controlled studies. Late in the evolution of AVN, joint replacement surgery may be needed if the normal architecture of a joint such as the hip is destroyed and function is lost or pain is severe.
Ayurvedic medicine A complementary, holistic approach to health based on ancient Hindu texts. It is traced back to the sages of ancient India. These rishis are believed to have discovered the principles of Ayurveda during deep meditation. These principles were codified in the Vedas (knowledge) that form the religious texts of Hinduism. The Atharva-Veda is the source of Ayurveda. The basis of
Ayurveda is understanding a person's dosha. There are three doshas or types that can be initially viewed as being similar to the common body types: Ectomorph (light and slim), endomorph (heavy and big boned), and mesomorph (muscular and medium build). On top of these physical characteristics are layered information about learning styles, emotional tendencies, and spiritual inclinations. The three doshas are termed Vata, Pitta, and Kapha. One is usually dominant and one secondary.
These not only describe people but also determine what foods they should eat and what lifestyles are appropriate for them. According to this model, arthritis is thought to result from weakened digestion, poor diet, and disturbed equilibrium. Treatment of arthritis is not standardized. Individualized therapy can include steam baths, enemas, massage, bloodletting, herbs, exercises, yoga, fasting, and avoiding alcohol, meat, and certain vegetables. Ayurvedic approaches to medicine have not been adequately evaluated in well-designed studies.
back pain A surgeon in the United States can operate on someone in the Middle East with a remote-controlled device. Scientists can build specific proteins to block complex molecules secreted by white blood cells in the body or to deliver drugs to a specific subset of cells in the body. Researchers can even predict the later development of certain cancers at the time individuals are born. However, we have no answer to the rising epidemic of simple low-back pain. This does not mean that back pain is new. There is a written description of sciatica dating back to 1500 B.C. and back pain appears to have been a common problem in medical writings from the 1800s. In particular, the disability associated with back pain is on the increase rather than back pain itself. Studies in Scandinavian countries over the last 40 years show no increase in the rate of occurrence of back pain over that time. There is no evidence to suggest that the pathology or nature of the problem is changing. However, the percentage of Swedish workers taking time off work because of back pain increased from 1 percent in 1970 to 8 percent in 1992, and the average number of days they took off increased from 20 to 39 per year. Why, when people do less physical work and the treatment possibilities are so much greater, should disability increase? The answers may be as much sociocultural as medical. Between 1991-93, the Swedish government progressively reduced sickness benefits (although they remain generous), and total sick leave for back pain fell from 28 million days in 1987 to 19.2 million days in 1995. Studies in less developed countries like Oman and Nepal show that back pain is extremely common, but very few people are disabled because of it. Hardly anyone in these countries takes to their bed or stays off work because of back pain.
Population surveys show that around 60 percent of adults have experienced low-back pain at some time, a figure confirmed in several developed countries. In the 45- to 59-year-old age group, this rises to about 70 percent. Many of these people will have had short-lived back pain not requiring any treatment. A third of the population has had back pain lasting more than a day in the previous 12 months. About 6 percent have chronic disabling back pain. This can be compared with the 1 percent that has the most common chronic inflammatory arthritis, rheumatoid arthritis. In the United States, back pain is the commonest cause of activity limitation in people under 45 years of age. There is no significant difference in the numbers of men and women reporting pain.
In any given year, 30 percent of adults who have never experienced back pain will do so. For those who have had back pain previously, the figure is just over 40 percent. In a 12-month study 10 percent of men and 7 percent of women between the ages of 20-59 years had time off work because of back pain. Back pain is conventionally divided into acute or chronic by virtue of persisting for less than or more than three months, respectively. This is because the three-month cutoff separates patients with quite different characteristics and underlying problems. A third group of patients (recurrent) have had back pain for less than three months but have also experienced previous attacks.
Much back pain is attributed to the abnormalities of the intervertebral disc, and sometimes the disc is indeed the culprit. In the adult, the top and bottom of each vertebral body is covered by a thin sheet of cartilage (as found in joints), the outer rim of which is calcified (that is, bony). Attached to this outer rim are concentric layers of tough fibrous tissue (the annulus fibrosis) that spiral round at an angle of 70° to the vertebral body to attach to the next vertebral body. Each successive layer is at right angles to the previous one, thereby increasing the ability to withstand torsion. contained within these layers is a gelatinous substance called the nucleus pulposus. This allows for free movement as well as providing a shock-absorbing ability. Important changes occur as we age. The nucleus pulpo-sus loses water, becoming smaller and stiffer. cracks and tears start to develop in layers of the annulus fibrosis after the age of about 30 years. This occurs particularly in the inner two-thirds that has no blood supply. These changes may lead to significant weaknesses and possibly bulging of the annulus fibrosis. The forces on the erect spine are always tending to squeeze the nucleus out of its contained space. Generally, it is most likely to be forced either upward or downward into the adjacent vertebral body or outward through the retaining annulus fibrosis. It is likely that this actually occurs only with a sudden increase in force. Apart from pain, such disc-bulging or protrusion can lead to several spinal problems. Spinal movement will be reduced in the affected segments. Some forward tilting of the spine occurs due to loss of height of the disc. Bony protrusions or osteophytes develop around and abnormal stresses are placed on the posterior spinal or facet joints that may then develop osteoarthritis.
However, it is important to see back pain not as a disease entity but as a symptom that can arise from many different diseases or abnormalities. Approximately 90 percent of back pain patients have mechanical back pain. This is defined as pain from overuse of a normal structure or from trauma to or deformity of an anatomic structure (including the disc). The exact source and nature of this pain may be extremely difficult to pinpoint, and specific diagnoses vary between practitioners with different special interests. Some diagnostic labels that are applied to people in this group include disc derangement or disruption, annular tear, spondy-losis, degenerative disc disease, disc syndrome, lumbar disc disease, back sprain or strain, facet joint syndrome, spinal osteoarthritis, and sacroiliac injury. While these are all potentially valid diagnoses it is just not possible to be sure of the precise cause of the pain in many people.
A small proportion of patients with mechanical back pain will have nerve root impingement, usually known as sciatica. This can be due to direct pressure from disc material as the nerve leaves the spinal cord, a gradual narrowing of the canal through which the nerve exits the spine, interference with the nerve's blood supply, or simply swelling and inflammation close to the nerve.
The remaining 10 percent of patients with back pain have an underlying systemic disease, and there are many such possible causes. Inflammatory back pain is typified by ankylosing spondylitis, but reactive arthritis, psoriatic arthritis, and sarcoidosis can all cause spinal inflammation (see psoriasis and psoriatic arthritis). Infective spondylitis can be caused by any of the organisms causing infective arthritis. It should be considered particularly in intravenous drug users (where staphylococ-cal species and gram-negative bacteria such as Pseudomonas aeruginosa are common) as well as those with lowered immunity due to cancer, HIV infection, or other causes of chronic ill health. BRUcellosis frequently involves the spine or sacroiliac joints, and 50 percent of bone or joint tuberculosis is in the spine.
Tumors may arise in the spine (lymphoma, sarcoma, giant cell tumor, osteoid osteoma, heman-gioma, chordoma) or metastasize there from a primary cancer elsewhere (lung, breast, prostate, ovary, colon, and myeloma particularly). Bone disease such as paget's disease, osteomalacia, and osteoporosis can frequently cause back pain. Problems outside the spine may occasionally first present as back pain. Such conditions affecting internal organs include abdominal aortic aneu-rysm, kidney infection, pancreatitis, and colon cancer. Herpes zoster (shingles) may give rise to severe pain of uncertain cause for two or three days before the characteristic rash appears.
There are also well-described associations with back pain. While these might not physically cause the pain, the association is such that effective therapy will necessarily have to address them. These include obesity and smoking. Patients consulting their doctor for back pain are also more likely to have consulted for stress or mental disorders. Depression is thought to be a consequence of back pain more often than a precedent.
Almost all patients with a back problem complain of pain. Disability or restriction of activities is the most important association with back pain. Disability and restriction of activities are not the same, and there is no close correlation between them. There is also no close correlation between pain or disability and pathology or disease. Of note is that this means the severity of pain does not provide any information on the actual diagnosis. Some people with serious spinal pathology will have little disability while others with minimal pathology are seriously disabled. Many people with low-back pain will have pain elsewhere. This is most commonly in the neck but may be widespread. It is important to note that pain radiating into the leg does not necessarily indicate nerve root entrapment. The sacroiliac joint and associated structures frequently refer pain into the upper leg. Pain with numbness or tingling that radiates down the leg to the foot usually does indicate nerve root irritation, though.
Confusion has arisen because of the difficulty in making a precise anatomic diagnosis in many (some say up to 85 percent) patients with back pain as well as the controversy surrounding various diagnoses. The anatomic diagnosis means identifying which structure the pain is coming from or in which the primary problem lies. Everyone presenting with significant or persistent back pain should have a detailed history taken followed by a thorough examination by a practitioner skilled in this area. The management of back pain is improved if, at this stage, a differentiation or triage into one of three groups is made. These are
• Simple low-back pain
• Serious spinal pathology
Simple Low-Back Pain usually develops in patients aged 20-55 years. The pain may be in the lower back, buttock region, or thighs. It is mechanical in that it varies with time and physical activity, and apart from the pain, the patient is well.
Nerve Root Pain generally radiates to the ankle or foot. Frequently this unilateral leg pain is worse than the back pain. There is numbness or paresthesia in the same area and signs of nerve irritation such as reduced straight-leg raising that reproduces the pain. There is loss of power, loss of sensation, or altered reflexes in the area supplied by one nerve root.
Serious Spinal Pathology includes the inflammatory conditions, infections, tumors, metabolic bone disease, and other rare diseases mentioned above. Less than 5 percent of back pain is due to these. There is an increasing trend to use so-called red flags to identify these. This requires the clinician to run through a validated list of signs and symptoms that signal the possibility of serious pathology. Red flags include:
• Presentation younger than 20 years or older than 55 years
• Significant trauma such as a motor vehicle accident
• Constant, nonmechanical pain
• Thoracic back pain
• Previous history of cancer
• Drug abuse or HIV infection
• Systemical unwellness, including weight loss or fever
• Widespread neurological abnormalities (more than one nerve root)
• Deformity of the spine
• Bone destruction or collapse on X ray
Within the grouping simple low-back pain are of course many different syndromes and a large number of structures that may be giving rise to pain. However, most patients with simple back pain and no red flags do not need any diagnostic tests. Symptom-relieving treatment may be given in the expectation of an early recovery. Many patients with nerve root pain will also recover spontaneously and special investigations will not be required. All patients with positive red flags should have further investigations done immediately. In addition, those in the first two groups who do not improve significantly within six weeks should have further investigations. These may include appropriate blood tests looking for an underlying systemic condition and imaging. Blood tests may include those indicating inflammation such as EsR, tests for calcium and markers of bone turnover, as well as tests looking for various forms of cancer such as prostate specific antigen. These will be dictated by each individual's circumstances. Plain X rays show bony lesions well but may take some time to become abnormal. Technetium bone scans on the other hand are very sensitive in showing abnormalities early on but do not give very specific information. They are particularly useful if metastatic cancer (cancer that has spread) is suspected, although one particular cancer (multiple myeloma) may not be demonstrated in this way.
Magnetic resonance imaging (MRI) scans are the investigation of choice for demonstrating nerve root impingement and many other conditions such as tumor or infection. Apart from expense, the chief drawback of MRI scans is the frequent finding of abnormalities in normal people. As MRI scans became widespread in the early 1990s, it was found that 40 percent of adults with no back pain at the time had abnormalities on MRI of their lower spine. It has therefore become important for radiologists reporting these scans to specify the degree of the abnormality along internationally agreed guidelines. In particular, it must be recognized that degenerative changes in the discs are a normal aging process. The MRI abnormalities should also be in keeping with the clinician's expectations before they are accepted as the cause of the patient's problem. CT scans may also be useful, although they show the soft tissues less well. There is very little place for traditional myelograms (injection of dye into the fluid space around the spinal cord), although they are very occasionally combined with CT scanning to assist in the planning of surgery. An electromyogram (EMG) may be helpful in a few instances where nerve lesions are atypical or difficult to interpret.
The treatment of back pain clearly depends on the diagnosis, and this discussion will be limited to mechanical back pain. Many of the other causes will be discussed elsewhere in this book. As indicated above, the vast majority of people with acute back pain will recover spontaneously within a few days. Studies have shown that continuing with normal activities (excluding heavy lifting) actually leads to a better outcome in acute back pain than either specifically designed back exercises or bed rest for a few days. Indeed, it has become apparent over the last 20 years that bed rest for more than a day or two leads to a much worse outcome. This is of course a dramatic change from an earlier era when rest was considered an important treatment for back pain.
Acute back pain For those people whose acute back pain lasts more than a few days or in whom the pain is very severe, treatment may be necessary. This group should first have serious disease excluded as above and be reassured about this. Aggravating or initiating factors should be looked for, and ways of avoiding or modifying these discussed. An explanation of the pain and possible causes is extremely important in enabling people to continue their normal activities while still having pain. Pain relief is often necessary, and either pain killers or NSAIDs are helpful. Manipulation may help reduce the pain more rapidly and improve mobility. Physical therapy as well as appropriate exercises may be prescribed or a referral made to an appropriate therapist to initiate these. The expected outcome should be discussed since many people have an overly negative view of back pain. Most patients seeking care for back pain (which is not everybody with back pain) will improve considerably over the first four weeks, but only 30 percent will actually be painfree. After four weeks, about a third will continue to have moderate pain and 25 percent will have marked limitation of activity. At 12 months, 70 percent will have had some recurrent back symptoms and 30 percent will have had intermittent or persistent pain of moderate intensity. About 15 percent will still have significant activity limitation at this stage.
Chronic back pain The treatment of chronic back pain is much more difficult and complex. Psychosocial factors assume greater importance here. Treatment modalities include manual therapies such as massage and manipulation, soft tissue injections, medication, exercise programs, corsets and braces, back schools, cognitive behavioral therapy, and work hardening (specific training to get fit for work activities). Most modern treatment programs for disabling chronic back pain would include cognitive behavioral therapy and exercise as substantial elements. Factors such as job dissatisfaction, relationship problems, and drug dependency that strongly impact on disability and illness behavior should be addressed. Work activities and the individual's fitness to undertake this must be assessed. Work-hardening programs analyze the individual's physical requirements at work and design a training program specifically to prepare them for this. posture, both at work and during daily activities, frequently needs correction. Manipulation is less helpful than in acute back pain. corsets and braces are generally best avoided but may provide some pain relief early in the course of treatment when used in conjunction with an exercise program. Analgesics, NSAIDs, and muscle relaxants are often used with effect.
Evidence-based treatment Because back pain is such a huge health care problem, the u.s. Agency for Health Care Policy and Research spent over two years and $1 million evaluating the scientific evidence for the effectiveness of the various treatments for back pain in the early 1990s. This has since been updated by both Dutch and British researchers, and the results are very briefly summarized here.
• Good evidence indicates that continuing ordinary activities leads to as good or better symptom re-lief and less disability than more traditional approaches including specific exercises and short-term rest. Graded reactivation over days or weeks with behavioral management makes no difference initially but leads to less long-term disability.
• Manipulation results in a quicker reduction in pain and better mobility in the first six weeks of back pain, but evidence for its value in chronic pain is inconclusive. When properly carried out, the risks of manipulation are very low. McKenzie exercises (extension or flexion exercises) probably provide some benefit in acute back pain. However, it has not been shown that other back-specific exercise programs are helpful in acute back pain. On the other hand, strong evidence indicates that exercise therapy is beneficial in chronic back pain.
• Local therapies such as ice, heat, short-wave diathermy, massage, and ultrasound may provide some short-term relief, but they do not alter the outcome. Traction is probably not effective for either simple low-back pain or sciatica. There is no evidence that transcutaneous electrical nerve stimulation or TENS is effective for either acute or chronic low-back pain.
• The use of orthotic shoe insoles in appropriate patients is probably helpful, but correction of leg length differences of less than 2 cm is not. There is no evidence for the use of lumbar supports or corsets. Biofeedback is probably not effective in chronic low-back pain.
• The evidence for soft tissue injections is equivocal. Evidence is contradictory regarding the use of acupuncture in chronic back pain. Reasonable evidence is available to support the use of epidural steroid injections in both chronic low-back pain and specifically in sciatica. Facet joint injections have not been shown to be effective.
• Back schools vary considerably in content, but there is some evidence that this form of therapy is more effective than other types of conservative treatment. There is also reasonable evidence in favor of behavior therapy.
• acetaminophen, NSAIDs, and acetaminophen-opioid combinations are all effective in acute and chronic back pain, but no one is better than the others. There is strong evidence that muscle relaxants are effective in acute low-back pain and possibly in chronic, but they have significant side effects.
• There is good evidence that narcotics and benzodiazepines for more than two weeks, colchicine, systemic corticosteroids, bed rest with traction, manipulation under anesthesia, and the use of plaster jackets are bad for the patient.
Surgery Patients with definite nerve root impingement in whom sciatica is severe, is disabling, and does not improve within four weeks or gets progressively worse will probably benefit from
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