Almost everyone reports back and/or neck pain at some point in their lives. Large population surveys have revealed three out of four people can remember having spinal pain, with almost one in three people report that they have experienced back and/or neck pain in the last 3 months. These surveys report that episodes of spinal pain begin to occur during teenage years, are most common during mid life, and are also reported by many elderly people.
Causes of Spinal Pain
Many theories exist as to the cause of common neck and back pain, but all theories are difficult to prove because of the lack of ability to visualize pain production by the structures of the back. Muscle pulls, tears or strains have been postulated to cause back pain mainly because of the muscle tenderness, tightness and spasms that frequently accompanies low back pain episodes. Proving muscle problems has been difficult however. As mentioned above, few people report activities that placed physical strain to the muscles at the time of onset of symptoms. Additionally, imaging fails to demonstrate any evidence of swelling, damage or bleeding in the muscles of the spine, whereas these finding are clearly demonstrated in imaging of damaged muscles in other areas of the body.
Even though degeneration of the spine occurs in everyone, many medical and surgical spine experts theorize that degeneration of the intervertebral discs is responsible for most acute, recurrent and chronic spinal pain. As discussed above, a major component of disc deterioration is the development of progressive tears in the anulus fibrosis, called anular tears. It is suspected that when some anular tears spontaneously extend themselves through additional the rings of the anulus, some people experience a pain response as neck or back pain. Though extension of anular tears is a possible explanation for the spontaneous onset of episodes of acute or recurrent back pain, mechanisms through which the disc degeneration can produce chronic back pain are not known. For chronic spinal pain, it seems more likely that neurological mechanisms are the more likely source of pain.
Degeneration of the facet joints is suspected to cause pain in some individuals, especially in the elderly. However, as facet joint degeneration is present in everyone beyond middle age, and only some of the elderly have pain, it appears that facet joint pain may be more the exception than the rule.
Some spine experts theorize that some spinal pain results from self-limited (and harmless) local areas of neuromuscular dysfunction, termed myofascial pain. This theory holds that bands of muscle tissue within the muscles that surround the spine develop increased involuntary tension at rest, resulting in muscle shortening, irritability, stiffness, and rapid fatigability. Further, it is theorized that these tense areas of muscle, called trigger points, interact with the pain system to cause local pain. These painful areas are common and minor in many people, and do not represent any type of severe pathology, inflammation or disease process. However, it is theorized that for some people these areas may induce intense and prolonged stimulation of the pain system. It is further postulated that these areas of neuromuscular dysfunction are susceptible to neurological influences which generally increases muscle tension, such as worrying, anger and stress.
Onset of Symptoms
Studies of the onset of spinal pain have found surprising results. Despite the commonly held belief that people "hurt their back" or "strain their neck" by performing strenuous activities, most episodes of low back pain occur without incident or with a common daily activity such as bending, twisting or sneezing.
Did You Know? In one large study of people with simple back pain, 70% of people could not identify anything that was associated with the onset of their pain.
In fact, many episodes are first noted upon awakening in the morning, or have gradual onset over several days. Some episodes of low back pain do begin following trauma such as a fall or accident, and some episodes begin with lifting heavy objects, but these are more the exception than the rule. These mechanisms of injuries may be "the final straw" which allows the changes of spinal degeneration to be experienced as pain.
Patterns of Spinal Pain
Fortunately, most episodes of pain are relatively brief and last for several days to a few weeks. These brief episodes are called
acute back pain and
acute neck pain. Many people report that pain episode occur repeatedly over the years (
recurrent back and recurrent neck pain). For some people, pain persists for months or years. These are called
chronic back pain and
chronic neck pain. Chronic spinal pain may begin following a typical episode of acute spinal pain or might come on gradually over days or weeks.
The intensity of spinal pain shows great variability from person to person. Some people report episodes of intense pain that makes normal physical activities almost impossible. Fortunately, intense pain episodes usually last for only several days. After the first few days, most people report that pain is bothersome, but tolerable. Pain location can vary from the center, right or left of the spine, or may be experienced across the whole back or neck. Some people report that pain radiates to the shoulder, back of head, pelvis or hips. Most people find that certain positions or movements of the spine are painful, and many report pain with standing, sitting, rotating, bending or reaching. Sometimes the painful areas are tender to touch or local pressure.
For people with chronic or daily pain, most report mild to moderate symptoms that fluctuate from day to day. Many people note daily patterns of symptoms. For example, some people report that their pain is greatest in the morning, or worse with sitting or driving. Because most daily demands of life require our active participation regardless of pain, most people learn that they can continue with daily activities despite their pain. Many people with chronic pain report sudden episodes of more intense pain, often called flares, during which performing required activities is more challenging.
Functioning with Spinal Pain
As acute, severe neck or back pain usually lessens within several days, many people are able to maintain essential life activities including work. Some find this more difficult. As symptoms lessen however, the vast majority of people quickly resume most normal activities, including household activities, exercise and work. Of interest, most people return to activities well before pain has resolved. This does not appear to have any deleterious effect on full recovery, and certainly help to minimize the impact of spinal pain on essential personal roles.
Did You Know? In one research study of people with recent onset of back pain, those who were told by the doctors to return to normal activities as quickly as could be tolerated were actually found to have less pain than those who were recommended either rest or physical therapy.
For people with chronic spinal pain, activity tolerance shows much greater variability. This reflects individual differences in pain tolerance and in beliefs about the importance of pain. Most people function at normal or near normal levels despite their chronic pain, and realize that although certain activities may increase pain, they do not cause harm. However, some people choose to avoid activities that produce pain, and exhibit significant life dysfunction because of their pain. Surprisingly, there is no evidence that avoidance of activities lessens daily pain or improves overall quality of life. On the contrary, people who avoid activities because of pain are found to report greater levels of daily pain are much less satisfied with their lives and often report significant discouragement or depression.
Treatment for Spinal Pain
Whether neck or back pain are produced by progression of spinal degeneration, anular tears of the intervertebral discs, or myofascial dysfunction, recovery has little to do with tissue healing. Degenerating tissue has extremely limited (if any) ability to repair, and areas of painful muscles are not truly injured. Improvement in pain must therefore dependent on processes other than healing. These processes are likely 1) resolution of inflammation and 2) adaptation of the nerve elements that monitors the spine structures to the degeneration that is present. For most episodes of spinal pain, these processes happen over time even when no specific "treatment" is used. This tendency for improvement without treatment has made it difficult for research to demonstrate the advantage of any treatment over no treatment at all.
Stay Active
Perhaps the most powerful treatment for episodes of spinal pain is straightforward advice to stay as active as tolerated. The mechanism of action by which continued activities promotes recovery is unexplained. Some medical providers theorize that activities may reduce the heightened pain sensitivity in the nervous system. Perhaps the benefit of continued activities is simply that daily activities are a distraction from pain, causing time to recovery to pass more quickly. Continuing to stay active may also have benefit in terms of lessening fears and concerns about the spine. A productive day during an episode of pain may act as reassurance, for one is able to continue with life as desired despite spinal pain.
Recommendations such as avoidance of bending or lifting with the back, special sleeping positions, the avoidance of high heeled shoes has long been given to people with back pain. However, no plausible scientific evidence exists to support these recommendations, and following them has not been demonstrated to have any benefit.
Medications
While acknowledging the limitation in actual healing, most medical treatments target reducing pain and inflammation while attempting to hasten adaptation of the nervous system. Initial management of spinal pain often includes use of anti-inflammatory medication (aspirin, ibuprofen, etc) and analgesics (acetaminophen) to help control pain. Muscle relaxants are also commonly prescribed, though their effectiveness is marginal, and sedation a frequent side effect. The use of narcotic analgesic is not mandated by spinal pain, and if a person decides to use these medications, they should be used sparingly and for no more than one week. Recent studies have shown that the use of narcotic analgesics for more than seven days, and that simply refilling a prescription for narcotics are major risk factors for the persistence of spinal pain, or development of chronic pain. Local application of cold packs or heat to the back may also provide temporary symptomatic relief.
Exercise
Exercise is often recommended for spinal pain. Exercise has received extensive study. Of great importance, it is generally concluded that exercise is safe including for people with spine problems, and it is risk neutral for additional injury or increased pain. In terms of pain reduction, for acute spinal pain, the advantage of exercise over no treatment at all is not clear. However, exercise is usually well tolerated, and successful exercise often results in improved confidence for resuming other activities such as house and yard work. Exercise has only a marginal effect, if any, for prevention of future spinal pain. This is compatible with the cellular model of spinal degeneration as discussed above which stresses that cellular loss and not physical activities are the ultimate case of spinal degeneration and pain.
Exercise should general include stretching of the painful area to help the muscle maintain their normal length and fully relax. Stretching is usually done slowly, and the stretch is held at the end of range for 30 seconds. Low level exercise is also advised during the acute phase of spinal pain, with simple walking the easiest to tolerate. Floor exercises or exercises with light weights that put the muscles through their full range of motion under some resistance are often helpful.
For people with chronic spinal pain, exercise has been found to be the most beneficial conservative treatment. In addition to exercise being as safe for people with chronic pain as it is for anyone else, exercise can reverse deconditioning that may have resulted from prolonged avoidance of strenuous or painful physical activities. Exercise, if done in a vigorous way, can improve the flexibility of the spine, the strength of the neck and trunk muscles and general fitness including endurance. The spine becomes the best it can be for the conditions that are present. The direct benefits of these improvements are obvious. Improved flexibility, strength and endurance make it easier to perform the daily tasks that utilize our spine.
A second benefit of exercise for those with chronic pain is general improvement of pain intensity. The mechanisms by which exercise reduces chronic spinal pain are unclear. It has been observed that consistent exercise may increase an abnormally low pain threshold, so that higher amounts of physical activities are needed to stimulate pain production. Several weeks of regular exercise is often required to gain this benefit, with sustained benefits occurring with long-term exercise strategies.
Surgery
Some people with severe and persistent spine pain elect surgery as a treatment for their pain. Referring back to the theory that the unique interaction between spinal (or disc) degeneration and the individuals nervous systems produces pain, surgery for spinal pain attempts to diminish the ability of the degenerative parts of the spine to stimulate the nervous system. Three types of surgical procedures, posterior-lateral fusion, anterior-posterior fusion and disc replacement are employed to accomplish this. All have shown similar effectiveness.
For decades, orthopedic and neurosurgeons have been performing posterior-lateral (back of the spine) spinal fusions procedures to treat spinal pain, especially in the lumbar region. The goal of posterior-lateral spinal fusion is to eliminate motion between vertebrae, which theoretically would lessen the ability of movement between those vertebrae to stimulate pain receptors. The surgery exposes the bone surfaces of both sides of the spinal arch of two or more vertebrae, and places fragments of fresh bone in such a way that as the bone heals, the vertebrae are joined together. Posterior-lateral spinal fusion surgery evolved over the last twenty years and now often uses metal devices to hold the vertebrae in place during the healing phase. The success rates from posterior-lateral fusion surgery are modest. Many people reported overall improvement, but most still experiences some daily spinal pain.
It is theorized that for maximum effectiveness, lumbar spinal fusion surgery should also remove the intervertebral disc, and thus eliminate any possibility of the disc stimulating pain receptors. For this reason, many lumbar spinal fusion surgeries now includes removal of the disc at the fusion level(s) and placement of bone materials and stabilizing mechanical devices into the former disc space. These anterior (front of spine) fusion surgeries aim to develop a bone connection between the vertebral bodies. Anterior fusion surgeries are often combined with posterior-lateral fusions, and these anterior-posterior fusions are currently the most common types of fusion surgeries done in the lumbar region. Their success rates are modest, and some persistent pain following fusion surgery remains common.
The theory held by some spine experts that the intervertebral disc is the primary source of back pain has lead to the development of a third type of spine surgery for primary spinal pain, replacement of the degenerated disc with an artificial disc. As with the anterior fusion surgery, artificial disc surgery eliminates the disc, but instead of filling the prior disc space with bone, a mechanical disc is placed into the space. The theoretical advantage is that the artificial disc allows limited motion between the vertebrae, and can therefore share some of the movements of the spine with the remaining discs. It is hypothesized that by preserving motion, degeneration of the remaining discs with be slowed. To date, results from artificial disc surgeries are similar to those from spinal fusion surgeries, with many patients noting improved pain, but most also reporting some continued spine pain problems.
The term radiculopathy refers to pain, tingling and/or weakness in the arm or leg caused by stimulation, inflammation, compression or damage to a spinal nerve roots. Cervical radiculopathy results from disorders that affect the cervical nerve roots and is experienced in the shoulder girdle and/or arm. Similarly, lumbar radiculopathy produce symptoms in the pelvis and/or leg. This pain is often called sciatica.
There are varying estimates of the frequency of radiculopathy within the population, and it is probable that almost two of every five people will experience a lumbar radiculopathy at some point in their lives, with about one in every fifty adults experiencing symptoms during any one year. Less is known about the rate of occurrences of cervical radiculopathy, though it is thought to be less frequent than lumbar radiculopathy. As with spinal pain, radiculopathy occurs most often in middle age, but also affects some teenage and elderly people.
Causes of Radiculopathy
Herniation of the intervertebral disc (discussed in detail under disc degeneration) is the most common cause of radiculopathy symptoms, particularly when this results in disc material occupying the vertebral canal or neural foramen (nerve opening) contact, displace or compress the passing nerve roots. It is essential to remember that disc abnormalities including disc herniation are noted on MRI scans in people who have no symptoms, and it is only when symptoms are present that correspond to nerve root compression that a disc herniation is considered important. Other causes of radiculopathy include spinal stenosis and synovial cysts of the facet joints that are discussed elsewhere.
Onset of Symptoms
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Onset of Sciatica
Because progressive disc degeneration and herniation result from loss of cellular function and not wear and tear caused from physical activities, the onset of radiculopathy symptoms would be expected to be similar to that of common spinal pain, and indeed this appears to be the case. In a recent study of lumbar disc herniation carried out at New England Baptist Hospital, it was observed that almost two out of three subjects reported that their radiculopathy began spontaneous, as no physical movement or activity coincides with the onset of symptoms. Some people report that their symptoms began while performing incidental movements such as bending, reaching or twisting. Less than one in ten people identify lifting something with the onset of symptoms, often only a light object.
Symptoms of Radiculopathy
A radiculopathy will produce a pattern of symptoms depending on the nerve root that is involved. However, considerable variability in symptoms is noted between people based on the severity of nerve root involvement, on individual differences in nerve sensitivity and on individual differences in the nerve supply to the skin and muscles.
When radiculopathy pain symptoms start in the neck or back, pain and radiates into the arm or leg, the correct diagnosis is usually made quickly. Some people experience pain only in the arm or leg, and these presentations can lead to considerable confusion as to the cause of the pain. In these cases, problems of the upper or lower extremity joints or muscles can incorrectly be blamed for symptoms. A few people report no pain symptoms at all, but instead experience only tingling, numbness and weakness of the affected arm or leg. Painless radiculopathy is diagnosed when the pattern of neurological findings matches that a single nerve root, and when other causes of these neurological symptoms are ruled out.
Symptom intensity also shows great variability between different people. For some, initial pain symptoms can be intense, making it unbearable to sit up, walk or get dressed, and almost impossible to find a position of comfort. Usually, intense pain only lasts for several days, but may persist for weeks. For many people, pain intensity is mild or moderate, allowing them to continue with most daily activities during their radiculopathy. Sensory symptoms of tingling and numbness are usually limited to several fingers of the hand, or part of the leg or foot. Although distracting, sensory symptoms are quite tolerable and rarely limit use of the affected area. Fortunately, weakness caused by radiculopathies is usually minor and many people sense that their strength is off, but find their weakness hard to pinpoint. In most cases, minor weakness does not influence daily function. However, some people experience weakness of the hand muscles or major leg muscles which may be severe. These people can experience severe difficulties in use of the hand, or difficulty with walking and climbing stairs.
Natural History of Radiculopathy - Expectations for Recovery
Regardless of treatment, recovery from cervical and lumbar radiculopathy symptoms is surprisingly rapid, with four out of five people feeling significantly better within several months. Pain resolution is thought to result from several important factors. The first factor is a gradual reduction of inflammation that is produced by the disc herniation. A second factor promoting recovery is a gradual absorption of the disc herniation or disc fragment. This process results from shrinking of the herniation associated with continued deterioration of the disc, and for extruded or sequestered disc fragments, from consumption of the disc fragment by macrophages - a specialized "clean-up" cell that is activated by damaged tissues in all parts of the body. Disc absorption is quite slow, occurring over many months or several years. A third factor, that is probably the most important reason for symptom resolution appears to be adaptation of the affected nerve root to the presence of the disc herniation. Nerve root adaptation is postulated to be extremely important because many people feel better long before the disc herniation has absorbed and is still contacting the nerve root, and nerve root adaptation is the only explanation for the findings of asymptomatic nerve root compression noted as incidental finding on spine imaging of many people without symptoms.
Recovery from neurological symptoms of numbness, tingling and weakness also occurs in most people within several months. To date, there is no evidence that this recovery is affected by any treatment, including surgery. Instead, the pace and degree of neurological recovery is dependent on the degree of damage to the nerve root caused by the root compression.
As described in anatomy section, nerve roots are made of hundreds of individual nerve fibers, each of which conducts electrical impulses to or from the body. Most fibers have an insulating coating made up of myelin, a molecule that is produced by Schwann cells. Myelin is essential for efficient nerve impulse conduction. When a nerve root is compressed, the myelin coatings of some of its nerve fibers are easily damaged. This produces a blockage of impulse conduction along those nerve fibers, resulting in inability of those fibers to communicate with our skin or muscles. Fortunately, Schwann cells can regenerate rather quickly and recoat the nerve fiber with myelin. This often occurs over several months, and is the mechanism that is responsible for the recovery of motor and sensory problems noted for most people with cervical and lumbar radiculopathies.
Some cases of nerve root compression are more serious, and result in damage of the actual nerve fibers. Unfortunately, nerve fibers cannot repair themselves, and if damaged the nerve fiber from the point of injury all the way to its target area of skin or muscle will disintegrate. When this occurs, the nerve fiber above the point of injury must regenerate, and grow all the way back to it muscle or skin. Nerve fiber regeneration is very slow, often taking years, and rarely results in much overall recovery. To date, we lack treatment to aid in nerve fiber regeneration.
Treatment for Radiculopathy
No treatment at all is required for many cases of radiculopathy. The symptoms may be tolerable from the onset, and improve rapidly.
If treatment is required, it is usually only needed for several weeks or months during the most painful phase of the radiculopathy. Conservative treatments generally target hastening inflammation and pain caused by the disc herniation, combined with activity recommendations that try to lessening the impact of the radiculopathy on daily activities. Surgical interventions are aimed at the mechanical aspects of the disc herniation, and remove the herniated disc material from the affected nerve root.
Stay Active
Though in the past, rest or activity avoidance was commonly recommended during acute radiculopathies, no evidence has been found to support this. It appears that continuing with activities as tolerated is safe, which for many people includes continuing or rapidly resuming daily tasks, exercise and work. Resuming activities as quickly as tolerated helps to lessen the impact of radiculopathies on peoples' lives, prevents deconditioning and also acts as a distraction from the pain. Some neurological symptoms such as weakness of major leg muscles or loss of hand strength can produce significant limitation for some activities. These restrictions may be required for several months before neurological function improves.
Medications
Some episodes of radiculopathy produce severe pain for several weeks. Treatment strategies then focus on reducing pain and inflammation during this phase of symptoms.. In these cases, the use of anti-inflammatory medications (aspirin, ibuprofen, etc) may be helpful for some people. Sometimes several days of oral corticosteroid medications, which have very powerful anti-inflammatory action, may also be prescribed. Pain medication such as acetaminophen may be helpful and can be combined with anti-inflammatory medication. Narcotic pain medications can be helpful for the most severe cases, and are usually limited to nighttime use to lessen pain and allow sleep. Muscle relaxants are generally not prescribed for radiculopathy symptoms.
Spinal Corticosteroid Injections
The inflammatory and pain aspects of radiculopathies can also be treated with injections of corticosteroids medication into the spine. These procedures use a needle inserted under X-Ray guidance into the epidural space or nerve opening to place medication into the area around the disc herniation. The corticosteroids are then slowly absorber for up to 4 weeks, and are postulated to reduce the inflammation that stimulated pain from the nerve root. When successful, spinal steroid injections may reduce the intensity of radiculopathy pain for several weeks, during the worst phase of pain symptoms. These injections do not influence neurological symptoms of tingling, numbness or weakness, nor do they alter long term outcomes including the total period of time needed for recovery. They do not influence the size of the actual disc herniation. Occasionally spinal steroid injections can be repeated. This is usually reserved for cases when the initial injection resulted in 3-4 weeks of symptom reduction, followed by an increase in pain intensity as the medication disappears. The rationale for a second (or third) injection is simple to provide another period of pain relief while waiting for the usual resolution of the pain symptoms.
Physical Therapy
Physical therapy has a limited role for the treatment of radiculopathy. Many types of treatments have been tried, including traction, heat, cold, ultrasound, electric stimulation and exercise, but non have shown convincing evidence of effectiveness. For some people, exercise may have a limited role of helping to maintain normal conditioning during a period of time when some activities are limited. Exercise does not change or improve weakness caused by dysfunction of the nerve root. Recovery of weakness and other neurological symptoms results from improved nerve function.
Surgery
Surgery is an effective treatment for radiculopathies in both the cervical and lumbar region. Surgery is directed as the mechanical aspect of disc herniations, and removes the herniated or extruded disc material, relieving the compression of the effected nerve root. Surgery is an elective treatment that is reserved for cases of severe pain that persists for many weeks without signs of improvement, for progressive weakness of muscles from worsening damage to the nerve roots caused by the disc herniation. In most cases, surgery results in a rapid reduction of pain. It does not appear to hasten the recovery of nerve function such as numbness or weakness. Surgery is always recommended for cases when the disc herniation is damaging the spinal cord in the cervical or thoracic regions, or in the lumbar region the lower nerve roots that control the bowel and bladder. In these cases surgery helps to prevent further loss of spine cord or nerve function which can have devastating long term consequences.
Surgical approaches for cervical disc herniations can approach the disc herniation from either the front of the neck, called anterior cervical discectomy and fusion (ACDF), or the back of the neck, called posterior discectomy or keyhole foraminotomy.ACDF is currently the most common surgical technique for cervical disc herniations. This approach requires an incision on the front of the neck followed by careful dissection around the muscles and neck structures to reach the front of the cervical spine. The problematic disc is then carefully removed in its entirety, including any disc materials that may be contacting the nerve structures. Following this, the disc space is filled with bone material called bone graft. This helps to maintain the distance between the vertebrae and promotes the development of a bone connection between the vertebral bodies. Many surgeons now attach a small metal plate over the disc space to hold the bone graft in place during healing. This allows the patient to begin moving the neck immediately, and negates the need for a neck brace. Most people feel better very quickly after ACDF procedures, and can return to light types of activities including work within a week. Full activities are usually resumed within 3-4 months.
Similar to ACDF, a new procedure called disc arthroplasty (disc replacement) is sometimes done as part of cervical disc herniation surgery. In this procedure an artificial metal or metal and plastic disc is inserted into the space instead of fusion. Early clinical results show good results for single level herniations that are similar to ACDF. Long term outcomes are not known, and advantages over the tradition ACDF are not established. For this reason, only some health insurance companies recognize or pay for disc replacement.
Posterior cervical discectomy or keyhole foraminotomy is performed under special conditions such as the location of the disc herniation within the spinal canal, the level of the disc herniation and other problems that are present in the cervical spine and neck. This procedure begins with an incision in the back of the neck, followed by careful dissection of the muscles from the back or the vertebra or lamina. The lamina is then partially removed to allow access into the spinal canal. The spinal cord and nerve roots are then gently moved to the side to expose the disc herniation, which is then removed from the spinal canal. Recovery from this procedure is usually rapid with return to most activities within weeks.
Lumbar microdiscectomy to remove a disc herniation is most common operation performed on the spine. Micro refers to optical magnification with a microscope or special glasses during the procedure. Optical magnification allows the procedure to be performed through a small incision with limited dissection through the muscles of the back. Many times a small amount bone is removed from the back of the vertebra (lamina) to gain exposure to the spinal canal and disc herniation. This is called a laminotomy. Once the surgeon accesses the spinal canal, the nerve roots are carefully moved to the side to expose the disc herniation. The herniated disc material is then carefully removed, and the surgical site closed. In most cases, lumbar microdiscectomy procedures are done as day surgery. Most patients are up and around within hours of the operation with many full recovery and resumption of normal activities within weeks.