You know it at once. It may be the fiery sensation of a burn moments after your finger touches the stove. Or it’s a dull ache above your brow after a day of stress and tension. Or you may recognize it as a sharp pierce in your back after you lift something heavy.
It is pain. In its most benign form, it warns us that something isn’t quite right, that we should take medicine or see a doctor. At its worst, however, pain robs us of our productivity, our well-being, and, for many of us suffering from extended illness, our very lives. Pain is a complex perception that differs enormously among individual patients, even those who appear to have identical injuries or illnesses.
In 1931, the French medical missionary Dr. Albert Schweitzer wrote, “Pain is a more terrible lord of mankind than even death itself.” Today, pain has become the universal disorder, a serious and costly public health issue, and a challenge for family, friends, and health care providers who must give support to the individual suffering from the physical as well as the emotional consequences of pain.
Ancient civilizations recorded on stone tablets accounts of pain and the treatments used: pressure, heat, water, and sun. Early humans related pain to evil, magic, and demons. Relief of pain was the responsibility of sorcerers, shamans, priests, and priestesses, who used herbs, rites, and ceremonies as their treatments.
The Greeks and Romans were the first to advance a theory of sensation, the idea that the brain and nervous system have a role in producing the perception of pain. But it was not until the Middle Ages and well into the Renaissance-the 1400s and 1500s-that evidence began to accumulate in support of these theories. Leonardo da Vinci and his contemporaries came to believe that the brain was the central organ responsible for sensation. Da Vinci also developed the idea that the spinal cord transmits sensations to the brain.
In the 17th and 18th centuries, the study of the body-and the senses-continued to be a source of wonder for the world’s philosophers. In 1664, the French philosopher René Descartes described what to this day is still called a “pain pathway.” Descartes illustrated how particles of fire, in contact with the foot, travel to the brain and he compared pain sensation to the ringing of a bell.
In the 19th century, pain came to dwell under a new domain-science-paving the way for advances in pain therapy. Physician-scientists discovered that opium, morphine, codeine, and cocaine could be used to treat pain. These drugs led to the development of aspirin, to this day the most commonly used pain reliever. Before long, anesthesia-both general and regional-was refined and applied during surgery.
“It has no future but itself,” wrote the 19th century American poet Emily Dickinson, speaking about pain. As the 21st century unfolds, however, advances in pain research are creating a less grim future than that portrayed in Dickinson’s verse, a future that includes a better understanding of pain, along with greatly improved treatments to keep it in check.
What is pain? The International Association for the Study of Pain defines it as: An unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage.
It is useful to distinguish between two basic types of pain, acute and chronic, and they differ greatly.
- Acute pain, for the most part, results from disease, inflammation, or injury to tissues. This type of pain generally comes on suddenly, for example, after trauma or surgery, and may be accompanied by anxiety or emotional distress. The cause of acute pain can usually be diagnosed and treated, and the pain is self-limiting, that is, it is confined to a given period of time and severity. In some rare instances, it can become chronic.
- Chronic pain is widely believed to represent disease itself. It can be made much worse by environmental and psychological factors. Chronic pain persists over a longer period of time than acute pain and is resistant to most medical treatments. It can—and often does—cause severe problems for patients.
Hundreds of pain syndromes or disorders make up the spectrum of pain. There are the most benign, fleeting sensations of pain, such as a pin prick. There is the pain of childbirth, the pain of a heart attack, and the pain that sometimes follows amputation of a limb. There is also pain accompanying cancer and the pain that follows severe trauma, such as that associated with head and spinal cord injuries. A sampling of common pain syndromes follows, listed alphabetically.
Arachnoiditis is a condition in which one of the three membranes covering the brain and spinal cord, called the arachnoid membrane, becomes inflamed. A number of causes, including infection or trauma, can result in inflammation of this membrane. Arachnoiditis can produce disabling, progressive, and even permanent pain.
Arthritis. Millions of Americans suffer from arthritic conditions such as osteoarthritis, rheumatoid arthritis, ankylosing spondylitis, and gout. These disorders are characterized by joint pain in the extremities. Many other inflammatory diseases affect the body’s soft tissues, including tendonitis and bursitis.
Back pain has become the high price paid by our modern lifestyle and is a startlingly common cause of disability for many Americans, including both active and inactive people. Back pain that spreads to the leg is called sciatica and is a very common condition (see below). Another common type of back pain is associated with the discs of the spine, the soft, spongy padding between the vertebrae (bones) that form the spine. Discs protect the spine by absorbing shock, but they tend to degenerate over time and may sometimes rupture. Spondylolisthesis is a back condition that occurs when one vertebra extends over another, causing pressure on nerves and therefore pain. Also, damage to nerve roots (see Spine Basics in the Appendix) is a serious condition, called radiculopathy, that can be extremely painful. Treatment for a damaged disc includes drugs such as painkillers, muscle relaxants, and steroids; exercise or rest, depending on the patient’s condition; adequate support, such as a brace or better mattress and physical therapy. In some cases, surgery may be required to remove the damaged portion of the disc and return it to its previous condition, especially when it is pressing a nerve root. Surgical procedures include discectomy, laminectomy, or spinal fusion (see section on surgery in How is Pain Treated? for more information on these treatments).
Burn pain can be profound and poses an extreme challenge to the medical community. First-degree burns are the least severe; with third-degree burns, the skin is lost. Depending on the injury, pain accompanying burns can be excruciating, and even after the wound has healed patients may have chronic pain at the burn site.
Central pain syndrome-see “Trauma” below.
Cancer pain can accompany the growth of a tumor, the treatment of cancer, or chronic problems related to cancer’s permanent effects on the body. Fortunately, most cancer pain can be treated to help minimize discomfort and stress to the patient.
Headaches affect millions of Americans. The three most common types of chronic headache are migraines, cluster headaches, and tension headaches. Each comes with its own telltale brand of pain.
- Migraines are characterized by throbbing pain and sometimes by other symptoms, such as nausea and visual disturbances. Migraines are more frequent in women than men. Stress can trigger a migraine headache, and migraines can also put the sufferer at risk for stroke.
- Cluster headaches are characterized by excruciating, piercing pain on one side of the head; they occur more frequently in men than women.
- Tension headaches are often described as a tight band around the head.
Head and facial pain can be agonizing, whether it results from dental problems or from disorders such as cranial neuralgia, in which one of the nerves in the face, head, or neck is inflamed. Another condition, trigeminal neuralgia (also called tic douloureux), affects the largest of the cranial nerves (see The Nervous Systems in the Appendix) and is characterized by a stabbing, shooting pain.
Muscle pain can range from an aching muscle, spasm, or strain, to the severe spasticity that accompanies paralysis. Another disabling syndrome is fibromyalgia, a disorder characterized by fatigue, stiffness, joint tenderness, and widespread muscle pain. Polymyositis, dermatomyositis, and inclusion body myositis are painful disorders characterized by muscle inflammation. They may be caused by infection or autoimmune dysfunction and are sometimes associated with connective tissue disorders, such as lupus and rheumatoid arthritis.
Myofascial pain syndromes affect sensitive areas known as trigger points, located within the body’s muscles. Myofascial pain syndromes are sometimes misdiagnosed and can be debilitating. Fibromyalgia is a type of myofascial pain syndrome.
Neuropathic pain is a type of pain that can result from injury to nerves, either in the peripheral or central nervous system (see The Nervous Systems in the Appendix). Neuropathic pain can occur in any part of the body and is frequently described as a hot, burning sensation, which can be devastating to the affected individual. It can result from diseases that affect nerves (such as diabetes) or from trauma, or, because chemotherapy drugs can affect nerves, it can be a consequence of cancer treatment. Among the many neuropathic pain conditions are diabetic neuropathy (which results from nerve damage secondary to vascular problems that occur with diabetes); reflex sympathetic dystrophy syndrome (see below), which can follow injury; phantom limb and post-amputation pain (see Phantom Pain in the Appendix), which can result from the surgical removal of a limb; postherpetic neuralgia, which can occur after an outbreak of shingles; and central pain syndrome, which can result from trauma to the brain or spinal cord.
Reflex sympathetic dystrophy syndrome, or RSDS, is accompanied by burning pain and hypersensitivity to temperature. Often triggered by trauma or nerve damage, RSDS causes the skin of the affected area to become characteristically shiny. In recent years, RSDS has come to be called complex regional pain syndrome (CRPS); in the past it was often called causalgia.
Repetitive stress injuries are muscular conditions that result from repeated motions performed in the course of normal work or other daily activities. They include:
- writer’s cramp, which affects musicians and writers and others,
- compression or entrapment neuropathies, including carpal tunnel syndrome, caused by chronic overextension of the wrist and
- tendonitis or tenosynovitis, affecting one or more tendons.
Sciatica is a painful condition caused by pressure on the sciatic nerve, the main nerve that branches off the spinal cord and continues down into the thighs, legs, ankles, and feet. Sciatica is characterized by pain in the buttocks and can be caused by a number of factors. Exertion, obesity, and poor posture can all cause pressure on the sciatic nerve. One common cause of sciatica is a herniated disc (see Spine Basics in the Appendix).
Shingles and other painful disorders affect the skin. Pain is a common symptom of many skin disorders, even the most common rashes. One of the most vexing neurological disorders is shingles or herpes zoster, an infection that often causes agonizing pain resistant to treatment. Prompt treatment with antiviral agents is important to arrest the infection, which if prolonged can result in an associated condition known as postherpetic neuralgia. Other painful disorders affecting the skin include:
- vasculitis, or inflammation of blood vessels;
- other infections, including herpes simplex;
- skin tumors and cysts, and
- tumors associated with neurofibromatosis, a neurogenetic disorder.
Sports injuries are common. Sprains, strains, bruises, dislocations, and fractures are all well-known words in the language of sports. Pain is another. In extreme cases, sports injuries can take the form of costly and painful spinal cord and head injuries, which cause severe suffering and disability.
Spinal stenosis refers to a narrowing of the canal surrounding the spinal cord. The condition occurs naturally with aging. Spinal stenosis causes weakness in the legs and leg pain usually felt while the person is standing up and often relieved by sitting down.
Surgical pain may require regional or general anesthesia during the procedure and medications to control discomfort following the operation. Control of pain associated with surgery includes presurgical preparation and careful monitoring of the patient during and after the procedure.
Temporomandibular disorders are conditions in which the temporomandibular joint (the jaw) is damaged and/or the muscles used for chewing and talking become stressed, causing pain. The condition may be the result of a number of factors, such as an injury to the jaw or joint misalignment, and may give rise to a variety of symptoms, most commonly pain in the jaw, face, and/or neck muscles. Physicians reach a diagnosis by listening to the patient’s description of the symptoms and by performing a simple examination of the facial muscles and the temporomandibular joint.
Trauma can occur after injuries in the home, at the workplace, during sports activities, or on the road. Any of these injuries can result in severe disability and pain. Some patients who have had an injury to the spinal cord experience intense pain ranging from tingling to burning and, commonly, both. Such patients are sensitive to hot and cold temperatures and touch. For these individuals, a touch can be perceived as intense burning, indicating abnormal signals relayed to and from the brain. This condition is called central pain syndrome or, if the damage is in the thalamus (the brain’s center for processing bodily sensations), thalamic pain syndrome. It affects as many as 100,000 Americans with multiple sclerosis, Parkinson’s disease, amputated limbs, spinal cord injuries, and stroke. Their pain is severe and is extremely difficult to treat effectively. A variety of medications, including analgesics, antidepressants, anticonvulsants, and electrical stimulation, are options available to central pain patients.
Vascular disease or injury-such as vasculitis or inflammation of blood vessels, coronary artery disease, and circulatory problems-all have the potential to cause pain. Vascular pain affects millions of Americans and occurs when communication between blood vessels and nerves is interrupted. Ruptures, spasms, constriction, or obstruction of blood vessels, as well as a condition called ischemia in which blood supply to organs, tissues, or limbs is cut off, can also result in pain.
There is no way to tell how much pain a person has. No test can measure the intensity of pain, no imaging device can show pain, and no instrument can locate pain precisely. Sometimes, as in the case of headaches, physicians find that the best aid to diagnosis is the patient’s own description of the type, duration, and location of pain. Defining pain as sharp or dull, constant or intermittent, burning or aching may give the best clues to the cause of pain. These descriptions are part of what is called the pain history, taken by the physician during the preliminary examination of a patient with pain.
Physicians, however, do have a number of technologies they use to find the cause of pain. Primarily these include:
- Electrodiagnostic procedures include electromyography (EMG), nerve conduction studies, and evoked potential (EP) studies. Information from EMG can help physicians tell precisely which muscles or nerves are affected by weakness or pain. Thin needles are inserted in muscles and a physician can see or listen to electrical signals displayed on an EMG machine. With nerve conduction studies the doctor uses two sets of electrodes (similar to those used during an electrocardiogram) that are placed on the skin over the muscles. The first set gives the patient a mild shock that stimulates the nerve that runs to that muscle. The second set of electrodes is used to make a recording of the nerve’s electrical signals, and from this information the doctor can determine if there is nerve damage. EP tests also involve two sets of electrodes-one set for stimulating a nerve (these electrodes are attached to a limb) and another set on the scalp for recording the speed of nerve signal transmission to the brain.
- Imaging, especially magnetic resonance imaging or MRI, provides physicians with pictures of the body’s structures and tissues. MRI uses magnetic fields and radio waves to differentiate between healthy and diseased tissue.
- A neurological examination in which the physician tests movement, reflexes, sensation, balance, and coordination.
- X-rays produce pictures of the body’s structures, such as bones and joints.
The goal of pain management is to improve function, enabling individuals to work, attend school, or participate in other day-to-day activities. Patients and their physicians have a number of options for the treatment of pain; some are more effective than others. Sometimes, relaxation and the use of imagery as a distraction provide relief. These methods can be powerful and effective, according to those who advocate their use. Whatever the treatment regime, it is important to remember that pain is treatable. The following treatments are among the most common.
Acetaminophen is the basic ingredient found in Tylenol® and its many generic equivalents. It is sold over the counter, in a prescription-strength preparation, and in combination with codeine (also by prescription).
Acupuncture dates back 2,500 years and involves the application of needles to precise points on the body. It is part of a general category of healing called traditional Chinese or Oriental medicine. Acupuncture remains controversial but is quite popular and may one day prove to be useful for a variety of conditions as it continues to be explored by practitioners, patients, and investigators.
Analgesic refers to the class of drugs that includes most painkillers, such as aspirin, acetaminophen, and ibuprofen. The word analgesic is derived from ancient Greek and means to reduce or stop pain. Nonprescription or over-the-counter pain relievers are generally used for mild to moderate pain. Prescription pain relievers, sold through a pharmacy under the direction of a physician, are used for more moderate to severe pain.
Anticonvulsants are used for the treatment of seizure disorders but are also sometimes prescribed for the treatment of pain. Carbamazepine in particular is used to treat a number of painful conditions, including trigeminal neuralgia. Another antiepileptic drug, gabapentin, is being studied for its pain-relieving properties, especially as a treatment for neuropathic pain.
Antidepressants are sometimes used for the treatment of pain and, along with neuroleptics and lithium, belong to a category of drugs called psychotropic drugs. In addition, anti-anxiety drugs called benzodiazepines also act as muscle relaxants and are sometimes used as pain relievers. Physicians usually try to treat the condition with analgesics before prescribing these drugs.
Antimigraine drugs include the triptans- sumatriptan (Imitrex®), naratriptan (Amerge®), and zolmitriptan (Zomig®)-and are used specifically for migraine headaches. They can have serious side effects in some people and therefore, as with all prescription medicines, should be used only under a doctor’s care.
Aspirin may be the most widely used pain-relief agent and has been sold over the counter since 1905 as a treatment for fever, headache, and muscle soreness.
Biofeedback is used for the treatment of many common pain problems, most notably headache and back pain. Using a special electronic machine, the patient is trained to become aware of, to follow, and to gain control over certain bodily functions, including muscle tension, heart rate, and skin temperature. The individual can then learn to effect a change in his or her responses to pain, for example, by using relaxation techniques. Biofeedback is often used in combination with other treatment methods, generally without side effects. Similarly, the use of relaxation techniques in the treatment of pain can increase the patient’s feeling of well-being.
Capsaicin is a chemical found in chili peppers that is also a primary ingredient in pain-relieving creams (see Chili Peppers, Capsaicin, and Pain in the Appendix).
Chemonucleolysis is a treatment in which an enzyme, chymopapain, is injected directly into a herniated lumbar disc (see Spine Basics in the Appendix) in an effort to dissolve material around the disc, thus reducing pressure and pain. The procedure’s use is extremely limited, in part because some patients may have a life-threatening allergic reaction to chymopapain.
Chiropractic refers to hand manipulation of the spine, usually for relief of back pain, and is a treatment option that continues to grow in popularity among many people who simply seek relief from back disorders. It has never been without controversy, however. Chiropractic’s usefulness as a treatment for back pain is, for the most part, restricted to a select group of individuals with uncomplicated acute low back pain who may derive relief from the massage component of the therapy.
Cognitive-behavioral therapy involves a wide variety of coping skills and relaxation methods to help prepare for and cope with pain. It is used for postoperative pain, cancer pain, and the pain of childbirth.
Counseling can give a patient suffering from pain much needed support, whether it is derived from family, group, or individual counseling. Support groups can provide an important adjunct to drug or surgical treatment. Psychological treatment can also help patients learn about the physiological changes produced by pain.
COX-2 inhibitors may be effective for individuals with arthritis. For many years scientists have wanted to develop a drug that works as well as morphine but without its negative side effects. Nonsteroidal anti-inflammatory drugs (NSAIDs) work by blocking two enzymes, cyclooxygenase-1 and cyclooxygenase-2, both of which promote production of hormones called prostaglandins, which in turn cause inflammation, fever, and pain. The newer COX-2 inhibitors primarily block cyclooxygenase-2 and are less likely to have the gastrointestinal side effects sometimes produced by NSAIDs.
In 1999, the Food and Drug Administration approved a COX-2 inhibitor-celecoxib-for use in cases of chronic pain. The long-term effects of all COX-2 inhibitors are still being evaluated, especially in light of new information suggesting that these drugs may increase the risk of heart attack and stroke. Patients taking any of the COX-2 inhibitors should review their drug treatment with their doctors.
Electrical stimulation, including transcutaneous electrical stimulation (TENS), implanted electric nerve stimulation, and deep brain or spinal cord stimulation, is the modern-day extension of age-old practices in which the nerves of muscles are subjected to a variety of stimuli, including heat or massage. Electrical stimulation, no matter what form, involves a major surgical procedure and is not for everyone, nor is it 100 percent effective. The following techniques each require specialized equipment and personnel trained in the specific procedure being used:
- TENS uses tiny electrical pulses, delivered through the skin to nerve fibers, to cause changes in muscles, such as numbness or contractions. This in turn produces temporary pain relief. There is also evidence that TENS can activate subsets of peripheral nerve fibers that can block pain transmission at the spinal cord level, in much the same way that shaking your hand can reduce pain.
- Peripheral nerve stimulation uses electrodes placed surgically on a carefully selected area of the body. The patient is then able to deliver an electrical current as needed to the affected area, using an antenna and transmitter.
- Spinal cord stimulation uses electrodes surgically inserted within the epidural space of the spinal cord. The patient is able to deliver a pulse of electricity to the spinal cord using a small box-like receiver and an antenna taped to the skin.
- Deep brain or intracerebral stimulation is considered an extreme treatment and involves surgical stimulation of the brain, usually the thalamus. It is used for a limited number of conditions, including severe pain, central pain syndrome, cancer pain, phantom limb pain, and other neuropathic pains.
Exercise has come to be a prescribed part of some doctors’ treatment regimes for patients with pain. Because there is a known link between many types of chronic pain and tense, weak muscles, exercise-even light to moderate exercise such as walking or swimming-can contribute to an overall sense of well-being by improving blood and oxygen flow to muscles. Just as we know that stress contributes to pain, we also know that exercise, sleep, and relaxation can all help reduce stress, thereby helping to alleviate pain. Exercise has been proven to help many people with low back pain. It is important, however, that patients carefully follow the routine laid out by their physicians.
Hypnosis, first approved for medical use by the American Medical Association in 1958, continues to grow in popularity, especially as an adjunct to pain medication. In general, hypnosis is used to control physical function or response, that is, the amount of pain an individual can withstand. How hypnosis works is not fully understood. Some believe that hypnosis delivers the patient into a trance-like state, while others feel that the individual is simply better able to concentrate and relax or is more responsive to suggestion. Hypnosis may result in relief of pain by acting on chemicals in the nervous system, slowing impulses. Whether and how hypnosis works involves greater insight-and research-into the mechanisms underlying human consciousness.
Ibuprofen is a member of the aspirin family of analgesics, the so-called nonsteroidal anti-inflammatory drugs (see below). It is sold over the counter and also comes in prescription-strength preparations.
Low-power lasers have been used occasionally by some physical therapists as a treatment for pain, but like many other treatments, this method is not without controversy.
Magnets are increasingly popular with athletes who swear by their effectiveness for the control of sports-related pain and other painful conditions. Usually worn as a collar or wristwatch, the use of magnets as a treatment dates back to the ancient Egyptians and Greeks. While it is often dismissed as quackery and pseudoscience by skeptics, proponents offer the theory that magnets may effect changes in cells or body chemistry, thus producing pain relief.
Narcotics (see Opioids, below).
Nerve blocks employ the use of drugs, chemical agents, or surgical techniques to interrupt the relay of pain messages between specific areas of the body and the brain. There are many different names for the procedure, depending on the technique or agent used. Types of surgical nerve blocks include neurectomy; spinal dorsal, cranial, and trigeminal rhizotomy; and sympathectomy, also called sympathetic blockade (see Nerve Blocks in the Appendix).
Nonsteroidal anti-inflammatory drugs (NSAIDs) (including aspirin and ibuprofen) are widely prescribed and sometimes called non-narcotic or non-opioid analgesics. They work by reducing inflammatory responses in tissues. Many of these drugs irritate the stomach and for that reason are usually taken with food. Although acetaminophen may have some anti-inflammatory effects, it is generally distinguished from the traditional NSAIDs.
Opioids are derived from the poppy plant and are among the oldest drugs known to humankind. They include codeine and perhaps the most well-known narcotic of all, morphine. Morphine can be administered in a variety of forms, including a pump for patient self-administration. Opioids have a narcotic effect, that is, they induce sedation as well as pain relief, and some patients may become physically dependent upon them. For these reasons, patients given opioids should be monitored carefully; in some cases stimulants may be prescribed to counteract the sedative side effects. In addition to drowsiness, other common side effects include constipation, nausea, and vomiting.
Physical therapy and rehabilitation date back to the ancient practice of using physical techniques and methods, such as heat, cold, exercise, massage, and manipulation, in the treatment of certain conditions. These may be applied to increase function, control pain, and speed the patient toward full recovery.
Placebos offer some individuals pain relief although whether and how they have an effect is mysterious and somewhat controversial. Placebos are inactive substances, such as sugar pills, or harmless procedures, such as saline injections or sham surgeries, generally used in clinical studies as control factors to help determine the efficacy of active treatments. Although placebos have no direct effect on the underlying causes of pain, evidence from clinical studies suggests that many pain conditions such as migraine headache, back pain, post-surgical pain, rheumatoid arthritis, angina, and depression sometimes respond well to them. This positive response is known as the placebo effect, which is defined as the observable or measurable change that can occur in patients after administration of a placebo. Some experts believe the effect is psychological and that placebos work because the patients believe or expect them to work. Others say placebos relieve pain by stimulating the brain’s own analgesics and setting the body’s self-healing forces in motion. A third theory suggests that the act of taking placebos relieves stress and anxiety-which are known to aggravate some painful conditions-and, thus, cause the patients to feel better. Still, placebos are considered controversial because by definition they are inactive and have no actual curative value.
R.I.C.E.–Rest, Ice, Compression, and Elevation-are four components prescribed by many orthopedists, coaches, trainers, nurses, and other professionals for temporary muscle or joint conditions, such as sprains or strains. While many common orthopedic problems can be controlled with these four simple steps, especially when combined with over-the-counter pain relievers, more serious conditions may require surgery or physical therapy, including exercise, joint movement or manipulation, and stimulation of muscles.
Surgery, although not always an option, may be required to relieve pain, especially pain caused by back problems or serious musculoskeletal injuries. Surgery may take the form of a nerve block (see Nerve Blocks in the Appendix) or it may involve an operation to relieve pain from a ruptured disc. Surgical procedures for back problems include discectomy or, when microsurgical techniques are used, microdiscectomy, in which the entire disc is removed; laminectomy, a procedure in which a surgeon removes only a disc fragment, gaining access by entering through the arched portion of a vertebra; and spinal fusion, a procedure where the entire disc is removed and replaced with a bone graft. In a spinal fusion, the two vertebrae are then fused together. Although the operation can cause the spine to stiffen, resulting in lost flexibility, the procedure serves one critical purpose: protection of the spinal cord. Other operations for pain include rhizotomy, in which a nerve close to the spinal cord is cut, and cordotomy, where bundles of nerves within the spinal cord are severed. Cordotomy is generally used only for the pain of terminal cancer that does not respond to other therapies. Another operation for pain is the dorsal root entry zone operation, or DREZ, in which spinal neurons corresponding to the patient’s pain are destroyed surgically. Because surgery can result in scar tissue formation that may cause additional problems, patients are well advised to seek a second opinion before proceeding. Occasionally, surgery is carried out with electrodes that selectively damage neurons in a targeted area of the brain. These procedures rarely result in long-term pain relief, but both physician and patient may decide that the surgical procedure will be effective enough that it justifies the expense and risk. In some cases, the results of an operation are remarkable. For example, many individuals suffering from trigeminal neuralgia who are not responsive to drug treatment have had great success with a procedure called microvascular decompression, in which tiny blood vessels are surgically separated from surrounding nerves.
The information provided here is in the public domain. My thanks to NINDS and the NIH for allowing it to be freely copied.