Lower Spine Pain and Injury
The lumbar spine plays a crucial weight-bearing role in our body’s movements and is comprised of the five vertebrae in your low back, situated just above the pelvis. We include the pelvis and sacroiliac joints in this as well, because problems with the pelvis can cause low back pain, too.
The University of Maryland Medical Center reports that 60 to 80 percent of the adult American population suffers from low back pain, and it is the leading cause of disability in Americans under the age of 45.
Another fact worth remembering is that back pain is a ‘relapsing remitting” condition – once a person has a sever episode, it is likely to recur. This is important to know, because this is why people with their first episode of back pain need to learn a whole new “back owners manual” – how to take care of their back to reduce back problems in the future. At IPCA we will always direct our patients to the best resources for this.
(back anatomy slides or video???)_
Muscle problems – Such as a muscle strain from heavy lifting, bending awkwardly, or overuse. This can cause short term pain – there is NO quality medical evidence that muscle strain or sprain can be a cause of chronic back pain.
Degenerative disc disease – While the intervertebral discs normally degenerate with time, just like our joints do; sometime the disc can be painful – like a torn knee cartillage can hurt, so can an intervertebral disc. This is more common in younger patients. Herniated discs – Sometimes also called a “slipped” disc, this occurs when the soft material inside an intervertebral disc is pushed outside the disc, like a grape that has been squeezed. This is a common cause of leg pain (sciatica).
Joint dysfunction – The lumbar facet joints can be painful if they are injured in an accident or have arthritis. The sacroiliac joint, located at the bottom of the lumbar spine and just above the tailbone, can be painfult – and this seems to be more common in women. This joint is particularly vulnerable to painful injury care accidents, it seems.
Many patients have what we call “functional” low back pain – meaning that their activity, muscle endurance, ability to support their back, posture, injuries to the lower extremities, diet, and other factors (like their job) are causing the back to hurt but there is no specific “injury”. Inflammation: some people have inflammatory conditions that affect the low back (as well as other joints). Examples would be rheumatoid arthritis, ankylosing spondylitis, and others.
Other diseases like cancer, pelvic organ pain (endometriosis is an exammple), compression fractures, abdominal aneurisms, infections of verterba or intervertebral disc are additional causes of back pain anywhere in the spine.
Treatment for a low back pain and injury depends on the exact nature of the condition. For example, in our older patients, spinal arthritits is common and CAN OFTEN be treated – most primary care providers do not know this. Spinal stenosis, usually a slowly prgressive degenerative process, can is a common cause of leg pain when standing and walking. This is treated conservatively with injections, minimally invasive decompression, and if necessary – surgery. Stress fractures, sacroiliac joint pain, intervetebral disc pain as common causes of back pain without leg pain – and non-surgical treatment for these problems is also available – for example, epidural steroid for pain control plus physical therapy to teach the patient how to take care fo their back for a disc herniation, pelvic floor therapy for sacroiliac joint pinjury in a car accident, thermal annuloplasty for injuries to the intervertbral disc without sciatic. it is important to know that one treatment alone is often not enough to get the best resutls, and this is where the Integrative Pain Center excels: getting to the right diagnosis + mathcing the right treatments to the patient and their problem + coordinating treatments to get the best results long term – with the least invasive program possible. Diet changes, weight loss, smoking cessation, rehabilitation and the right kind of excercise, preventative treatment (chiropractic. massage, Chinese medicine, etc) and knowledge of how to handle flare ups of pain without having to go to the doctor are key parts of our back pain treatment program. people sometimes ask about potent pain medicine, and for more about IPCA’s approach to medications for pain please go to: (the intro to pain medicines that is on the current website at http://www.ipcaz.org/introduction-to-pain-medications/ I don’t see this on this site yet)
For those who want to learn more about back pain:
Common Causes of Chronic Low Back Pain
The most common cause of recurring low-back pain is degeneration in the vertebral joints (facet joints and intervertebral discs). Vertebral joint degeneration can lead to a number of clinical syndromes (e.g., disc degeneration causing back pain, facet joint pain causing back pain, disc herniation causing leg pain, and spinal stenosis causing leg pain), but it is useful to consider these syndromes under a common conceptual framework.
There are nondegenerative causes of low-back pain as well, and these deserve consideration in appropriate circumstances.
Although this info point presents only the biological approach to understanding back pain, It is important to recognize that we have yet failed to define a single comprehensive unified biological model to explain back pain. Our failure reflects the overwhelming body of literature that suggests that environmental (work, etc) and psychosocial factors present significant obstacles to recovery in most patients with chronic back pain (A systematic review of psychological factors aspredictors of chronicity/disability in prospective cohorts of low back pain., (Pincus T Spine 2002 Mar 1;27(5):E109-20 http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=retrieve&db=pubmed&list_uids=11880847&dopt=abstract) .This underscores the importance of thinking of chronic back pain in terms of the “biopsychosocial model” (link to relevant Info point).It is important to note that there is little evidence for tendon, ligament, or muscle injury as a primary cause of chronic low-back pain (“Muscle spasm is a diagnosis both unreliable and invalid”, “If ligament sprain is a cause of back pain, it is uncommon” The biomechanics of Back Pain by Adams, Michael, Bogduk, Nikolai, Burton, Kim and Dolan, Patricia, Churchill Livingstone Press 2002, pg 74). Although painful myalgias and trigger points can result from an underlying skeletal derangement, presumably the result of reflex spasm and muscle splinting of the painful spine, diagnoses such as “chronic lumbar strain” (which suggests that chronic low-back pain is due primarily to a soft tissue injury are misleading and should not be used.
- Degenerative Disease of the Spine
- Lumbar Spondylolysis
- Vertebral compression fracture
- Sacral insufficiency fracture
- Rheumatologic disorders
- Spinal infection
- Metastatic disease
Degenerative Disease of the Spine
Spinal degenerative diseases such as painful degenerative disc disease, facet joint pain, disc herniation, or spinal stenosis should be viewed as a clinical continuum that:
- Begins with dysfunction
- Progresses to instability
- Ends in spinal fixation and stabilization
- Each of these phases of this continuum does not have to but can cause back pain and/or leg pain via several mechanisms
Pathologically, the early changes involve disc and/or posterior joint degeneration (however, usually discs degenerate before facets) , which lead to local instability and facet joint pain, to disc herniation,.to discogenic pain (painful radial annular fissures) (link to the note on discogenic pain at the end of this section), and later in the process to central spinal canal and neural foraminal stenosis.
It is best to consider spinal degenerative disorders as a group as they may all be present in various stages and at various spinal levels. Thus, a patient’s back discomfort may reflect the effects of more than one pathologic process. In addition, a patient may present at any point along the clinical continuum, depending on their work or athletic environment, pain tolerance, comorbidities, and genetic susceptibility.
Yon-Hing & Kirkady-Willis (1983) used clinical work and autopsy studies to develop a model of degenerative lumbar spine disease based on the interconnected relationship of disc joint disease and posterior (facet) joint disease. As spinal degeneration continues, it passes through a series of stages with predictable clinical findings. Which aspects of degenerative disease of the spine actually cause pain? It is useful to further clarify whether we are talking about back pain or leg pain.
- Back pain: Arthritis of the facet joints (painful arthritis has a prevalence of about 40% in older patients) and most likely radial annular fissures that extend into the outer annulus (discogenic pain) are thought to cause back pain (The biomechanics of Back Pain by Adams, Michael, Bogduk, Nikolai, Burton, Kim and Dolan, Patricia, Churchill Livingstone Press 2002, pg 74-77)
- Leg pain (sciatica): Disc prolapse/herniation and spinal stenosis. , and in some cases referred pain from the disc (Gilette, Ohmeiss) Of course, both back and leg pain can present together, for example in the older patient with painful degerative arthritis of the facet joints and spinal stenosis, or the younger patient with painful radial annular fissure and disc prolapse.
The continuum of degenerative spine disease and the interconnected relationships between disease in the posterior joints and the disc is shown below. Note that initially disease in one area (e.g., the disc) may dominate the clinical picture. However, as degeneration progresses all areas become involved.
Gray shaded areas are probable causes of back pain,
Lilac shaded areas are probable causes of leg pain
Stages of Degenerative Spine Disease
The clinical stages of degenerative spine disease (dysfunction, instability, and stabilization) have the following characteristic symptoms and findings:
Stage 1 – Dysfunction
- The patient presents with acute “mechanical” low-back pain without pain radiating consistently to one leg in a dermatomal pattern.
- If there is a disc problem, sitting is often the most painful position; traction relieves the pain temporarily. There is often early morning pain that wakes the patient and it is more comfortable to sleep on their side or in a recliner.often.
- The first episode is short-lived, self-limited, and improves with minimal intervention.
Stage 2 – Instability
- Back pain episodes increase in frequency and duration; they may become constant.
- Pain is often associated with radicular symptoms (pain radiating down the leg, usually below the knee, usually unilaterally, and in a dermatomal distribution) from nerve root compression.
- There are instability symptoms, such as a sudden sharp back pain with movement transitions, rolling over in bed at night, and with minimal bending and twisting. This type of pain may arise from an unstable facet joint or disk that is being stressed by even minor activity.
- Severe instability may cause positional nerve root impingement with radiculopathy. For example, radicular pain can be aggravated by extension of the spine and may become worse when lying down (when the patient relaxes the lumbar stabilizing muscles). Severe instability usually does not respond to conservative treatment.
- Disability increases. The pain may interfere considerably with work.
- There may be dermatomal sensory loss, reflex loss, and strength loss in the distribution of a lumbar root or roots due to disc herniation and/or spondylolisthesis.
- Positive neural tension testing may occur: the straight leg raising test provokes the patient’s typical leg symptoms, indicating compression of the nerve root by disc herniation.
- There may be degenerative scoliosis and perhaps degenerative spondylolisthesis on exam.
- A sudden sharp pain (a “catch”) and refusal to allow the lumbar spine to flex suggests instability between vertebral levels and requires radiographic evaluation.If facet disease is the primary pathological process, the patient may meet Revel’s clinical criteria for facet joint disease. (Link to Revel Criteria, below) Plain radiographs may demonstrate degenerative joint disease of the facet joints, disc space narrowing, osteophytes of the vertebral body, sclerosis of the vertebral endplates, gas within the discs “vacuum disc phenomenon”, and spondylolisthesis without spondylolysis.
- MRI studies may show broad-based disc protrusions, focal disc protrusions, disc degeneration with loss of height, the beginnings of spinal canal and neural foraminal stenosis, and changes consistent with those seen on plain x-rays.
Stage 3 – Stabilization
- Back pain may decrease during stage 3 as the spine loses mobility.
- There is neurogenic claudication: standing and ambulation lead to leg pain radiating below the knee on one or both sides and perhaps bilateral thigh pain. Neurogenic claudication is the hallmark of stage 3.
- There is decreased mobility of the lumbar spine and minimal pain on standing and forward bending.
- There is low back pain with lumbar extension.
- Lumbar extension and side bending may provoke radicular leg pain.
- The neurological exam is usually without focal findings.
- If there are focal neurological deficits due to severe nerve root compression, these are often related to old stable radiculopathy from earlier stages of spinal degenerative disease.
- Plain radiographs demonstrate the findings seen in stage 2 with more advanced disc degeneration, osteophyte formation, and degeneration of facet joints.
- MRI and CT studies show canal and neural foraminal stenosis, but “Clinical signs and symptoms do not appear to predict whether the results of imaging tests will show severe stenosis.” (AHRQ Report, 2001).
Link from above
A note on “discogenic” pain: Many believe this to be a major biological cause of so-called “non-specific low back pain”, of back pain without radiation to the legs. Adams expanded on the part of the process above that research suggests is the cause of “discogenic back pain”. Transfer of load bearing from the nucleus pulposis to the annulus fibrosis consequent to failure of the vertebral endplate adjacent to the nucleus of the disc leads to radial annular tears which are believed to cause much isolated low back pain.
(Adams MA Abnormal stress concentration in lumbar intervertebral discs following damage to the vertebral bodies: A cause of disc failure? Eur Spine Journal 1993: 1:214-244). This process can explain how patients may complain of back pain despite minimal and even no overt changes on imaging studies.
Lumbar (“Isthmic”, “juvenile”) spondylolysis
This is probably the most common cause of back pain in patients younger than 30 years. The lesion is a defect, either congenital or post-traumatic, in the narrow section of bone that joins the spinous process to the vertebral body, the pars interarticularis. The L4 and L5 vertebral bodies are the most commonly affected. Not all spondylitic lesions cause pain. Slippage of one vertebra over the other may occur if there are bilateral pars interarticularis lesions (as shown in the illustration). This is termed “spondylolisthesis”. Often patients with bilateral spondylolysis and spondylolisthesis go through life without back pain. When there is back pain due to spondylolysis, there is often a history of athletic activity, such as gymnastics, throwing sports, high jump, and American football. Typical symptoms include:
- Intermittent low back pain in the first and second decade
- Pain is typically worse with activity and relieved by rest
- Pain may also be worse with prolonged standing
- Pain may progress to more constant back pain during the third decade
- Exaggeration of the lumbar curve, perhaps with a palpable “step off” if there is significant spondylolisthesis
- The patient’s range of motion is usually normal
- Pain is provoked on hyperextension of the lumbar spine
- Hamstring tightness is common
- The neurological exam is usually normal
- Slippage of one vertebral body over another (as shown in this film)
- Lateral or oblique back films may show a spondylitic defect in the pars interarticularis
- Lateral standing flexion and extension views provide evidence for instability, demonstrating a change in the degree of slippage of one vertebra on another
More sophisticated imaging (bone scan, MRI, SPECT) can be helpful, and such studies are reasonable in a patient in whom a spondylolysis is suspected, but whose plain radiographs are normal.
This is not the same process as seen in degenerative spondylolisthesis, although the outcome can be the same. Symptoms of spinal instability can progress, with progressive impingement of lumbar nerve roots and the central spinal canal causing neurogenic claudication and radiculopathy.
Treatment is only necessary if symptoms are present and related to the spondylotic defect or to the resulting spondylolisthesis and instability. Treatment includes:
- Stabilization exercises and physical exercise
- Wearing an “anti-lordotic” corset, especially during activities that provoke pain
- Avoidance of extension exercises
- Percutaneous denervation of the fracture using the same technique as used for denervation of facet joints
Techniques to promote healing of the fracture, such as bone stimulators and biological treatments, are being studied.
Vertebral compression fracture
Vertebral compression fractures are present in about 4% of back pain patients seen in primary care (Deyo et al., 1992) They are usually the consequence of osteoporosis. However, they may occur in patients taking long-term steroid therapy (vertebral osteonecrosis) and as a complication of metastatic cancer. Patients taking steroid therapy need to be further evaluated for the possibilities of osteomyelitis and osteonecrosis.
- The patient experiences pain at the site of the fracture, usually with no neurologic findings.
- Many patients cannot stand or even sit for prolonged periods.
- Percussion over the fracture site is painful.
MRI is usually adequate to determine whether or not a compression fracture is the consequence of a malignant or benign process. MRI is also helpful in determining the age of the fracture. This is important information when considering surgical treatment.
Bed rest and analgesics may be sufficient in a generally healthy patient, and pain can be expected to resolve spontaneously in 3 or 4 months in most patients. Occasionally, bracing will allow faster resumption of activity, although this tends to be poorly tolerated for upper lumbar and thoracic fractures.
If recovery is insufficient in the first weeks, vertebroplasty and kyphoplasty (link to 20I-1) are effective for mild to moderate acute and subacute fractures where there is evidence of marrow edema on MRI. Occasionally, these techniques are indicated in the first week for more frail patients who are bedridden with fracture pain and at high risk for complications of inactivity.
Sacral insufficiency fracture
The usual symptoms are acute sudden onset presacral pain that becomes aching and spreads to the buttocks, with tenderness to percussion over the sacrum and lower lumbar vertebra much as one would see in a vertebral compression fracture. These are probably under-recognized as a cause of pain and osteoporotic patients. Symptoms may occur without a trauma history. A history of osteoporosis or other metabolic bone disease, pelvic irradiation, or corticosteroid therapy should alert the physician to this possibility. Bone scan and CT scan are usually necessary to detect these fractures.
Rheumatologic disordersThere are many rheumatologic disorders that produce spine pain. The ones to particularly consider are the seronegative spondyloarthropathies, such as:
- Ankylosing spondylitis
- Reiter’s syndrome
- Psoriatic spondyloarthritis
These diseases are characterized by painful involvement of the spine, most commonly the sacroiliac joints, the absence of rheumatoid factor, and a frequent association with the HLA-B27 antigen. Because patients may not have peripheral joint complaints and usually have a negative rheumatoid factor, they are often overlooked. You should think of the seronegative spondyloarthropathies in younger patients with chronic low back pain that is not clearly related to a traumatic incident.
Perhaps the most useful clinical finding on history and exam to support the diagnosis of a seronegative spondyloarthropathy is an “enthesopathy,” pain at the insertion of tendon into bone. The insertion of the Achilles tendon into the calcaneus is a common site for this finding. Morning stiffness and relief of pain with exercise are usually present as well.
The treatment of rheumatologic disorders, including seronegative spondyloarthropathies, includes disease-modifying antirheumatic drugs and, more recently, tumor necrosis factor inhibitors, such as infliximab and etanercept (Liu et al., 2004).
Discitis and osteomyelitis should be considered when low back pain occurs after spinal procedures or without trauma, especially in patients who are who are diabetic, immunosuppressed, or intravenous drug users.
One important characteristic of spinal infection is that the pain is often severe, even at rest and at night. Neurological manifestations are usually absent at first. Constitutional symptoms may be minimal, particularly with indolent infections such as coccidioidomycosis. MRI is very sensitive and specific.
The most common tumors to metastasize to the spine are breast, prostate, lung, kidney, and thyroid. Unremitting back pain that is present at rest and at night in a patient with no history of precipitating trauma, who is also at risk for any of these malignancies, should prompt further evaluation. MRI is very sensitive and specific.
Slump Test (Link from above)
The point of the slump-sit test is to differentiate between disc and posterior element pain. The test is done by having a seated patient flex their neck and plantar flex their foot (as shown). This places tension on neural elements and compresses the intervertebral discs, without allowing movement of other changes in the posterior spine, including potentially degenerative facet joints and any spondylitic defects. If the slump-sit text action produces the patient’s pain and neck extension and foot dorsiflexion relieve the pain, these findings suggests that the pain is due to disc disease.
Revel Criteria for Facet Joint Pain (Link from above)
Revel and his colleagues sought to find clinical features that would distinguish back pain responsive to facet joint injection (Revel et al., 1999). They measured the concordance between clinical criteria and subsequent relief from back pain following facet injection in 80 patients.
Seven clinical criteria were useful in distinguishing back patients who would respond to facet injection from those who would not (sensitivity = 92%, specificity = 80%). A positive “test” was considered the presence of pain that was relieved by recumbency and any four of the following:
- Age greater than 65 years
- Pain not exacerbated by coughing
- Pain not worsened by hyperextension
- Pain not worsened by forward flexion
- Pain not worsened when rising from flexion
- Pain not worsened by extension-rotation
To the extent that pain relief from facet joint injection is a marker for facet joint pain, this constellation of five or more negative findings in back pain patients suggests that the pain originates from posterior (facet) joint disease rather than other causes, such as disc degeneration. Unfortunately, sensitivity is low (<17%) and so these criteria cannot be used as a screening tool because the false negative rate will be too high and many with facet pain would be passed over. Specificity is good enough (>90%) that positive Revel’s criteria strongly suggest facet pain, so the test can be used only when results are positive. Laslett later found the following combination of factors in a more recent publication to be better, but not foolproof predictors of facet pain:
- Patient older than 50 yrs
- Pain best when walking and when sitting
- Pain is paraspinal
- Lumbar extension + rotation is painful
- Absence of centralization (pain does not focus in the midline lumbosacral junction) during repeated lumbar flexion/extension and side bending.
AHRQ Report: Treatment of Degenerative Lumbar Spinal Stenosis. Summary Evidence Report/Technology Assessment: Number 32. AHRQ Publication No. 01-E047. Rockville, MD: Agency for Healthcare Research and Quality, March 2001. Available online at http://www.ahrq.gov/clinic/epcsums/stenosum.htm
Deyo RA, Rainville J, Kent DL. What can the history and physical examination tell us about low back pain? JAMA. 1992;268:760-765.
Laslett, Mark BMC Musculoskelet Disord. 2004; 5: 43. at: http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=534802).
Laslett, Mark The Spine Jourmal 2006;6(4): 370-379
Liu Y, Cortinovis D, Stone MA. Recent advances in the treatment of the spondyloarthropathies. Current Opinions in Rheumatology. 2004;16:357-365.
Revel M, Poiraudeau S, Auleley GR, Payan C, et al. Capacity of the clinical picture to characterize low back pain relieved by facet joint anesthesia. Proposed criteria to identify patients with painful facet joints.
Spine. 1998;23:1972-1977 passim.
Yong-Hing K, Kirkaldy-Willis WH. The pathophysiology of degenerative disease of the lumbar spine. Orthopedic Clinics of North America. 1983;14:491-504.
“BUT DOCTOR, DON’T I NEED AN MRI?”
WHAT NATIONAL GUIDELINES SAY ABOUT WHEN XRAYS AND MRIS ARE USEFUL [Infopoint #16]
Imaging Studies in Back Pain
Imaging studies, particularly radiographic studies, are often overused in the management of back pain, and published guidelines have not improved the use of imaging studies as much as one would expect (Suarez-Almazor et al., 1997; Rao et al., 2002).
One reason that physicians frequently order imaging studies in back pain may be that patients expect them. A randomized trial of lumbar radiography in low back pain found that use of radiographic studies had no effect on patient functional outcomes, but it did improve patient satisfaction (Kendrick et al., 2001). Thus, the challenges facing physicians may be to manage patient expectations as well as to appropriately utilize expensive imaging procedures.
Some simple concepts may help you better understand (and explain to patients) when back imaging studies are likely to be helpful in the primary care setting. The key treatable causes of back pain (Link to #38) that can be confirmed via imaging studies are:
- Clinically relevant disc herniation
- Metastatic cancer
- Compression fracture
- Seronegative spondyloarthropathy (ankylosing spondylitis and others)
- Plain radiographs
- CT scans
- Bone scans
In-office, low-power MRI and ultrasound are being developed and may become useful screening tools in the future; however, these will probably not be widely used for at least the next 5 years.
“Imaging studies do not test for pain. Rather, they identify structural abnormalities which may or may not correlate with production of pain.” (North American Spine Society. Unremitting low back pain. LaGrange (IL): North American Spine Society (NASS); 2000:23) (Link to NASS site: http://www.spine.org/guidelines.cfm)
- Positive radiographic findings alone have little correlation with the presence or absence of back pain (Frymoyer et al., 1984; Phillips et al., 1986).
- Positive MRI findings alone often have no relationship to the presence or future development of back pain (Jensen et al., 1994; Borenstein et al., 2001).
Therefore: Imaging studies should be used only to confirm clinical findings.
When should back imaging studies be used in primary care? Which studies?
The following recommendations consider the sensitivity, specificity, and cost of plain lumbar radiographs, CT scans, bone scans, and MRI studies for osteomyelitis, compression fracture, metastatic cancer, seronegative spondylitis, and disc herniation (Jarvick, 2003).
When back pain is the chief complaint without pain radiation below the knees, one needs to be selective. 1. Uncomplicated acute low back pain does not require imaging (no risk factors for metastatic disease or osteomyelitis: age less than 50, no history of diabetes mellitus or intravenous drug abuse, no history of cancer, no fever, no weight loss). Imaging studies are probably unnecessary (Atlas & Deyo, 2001; Atlas & Nardin, 2003). 2. Uncomplicated low back pain that has not improved in 6-8 weeks, and complicated acute low back pain may need imaging studies to confirm a clinical diagnosis (patients who have one or more of the risk factors mentioned above). The appropriate first step is to obtain plain radiographs (and probably an erythrocyte sedimentation rate). X-rays of the sacroiliac joints should be ordered if inflammatory spondylitis is a possibility. If you suspect segmental instability, standing flexion and extension films may document this. If you suspect spondylolysis, oblique films may demonstrate the pars fracture. Consider an MRI when the suspicion of systemic disease is high, and the first line imaging (plain films) is nondiagnostic. MRI is sensitive and specific for infection and for infiltrative processes of the vertebral body. MRI is also valuable for providing information regarding the age of compression fractures, which is crucial to planning treatment. When back pain is the chief complaint, and there is pain radiation below the knees, MRI is the most useful study. The appropriate test is an MRI if: A. There has been no improvement after at least 6 weeks of conservative care or, B. The situation is urgent (there is persistent debilitating pain despite analgesia, urinary retention, saddle anesthesia, severe weakness, or there are bilateral neurological findings). When neurogenic claudication is present (usually in an older adult), consider MRI. MRI is reasonable when symptoms are intolerable or neurologic deficits are evident. MRI outperforms CT because it is more sensitive for soft tissue (disc) encroachment on neural foramina. The two are roughly equivalent when evaluating central canal stenosis. Note that “Clinical signs and symptoms do not appear to predict whether the results of imaging tests will show severe stenosis.” (AHRQ Report, 2001) Roughly 20% of asymptomatic individuals over age 60 will have at least moderate spinal canal stenosis on CT or MRI (Porter & Bewley, 1994). The likelihood of finding incidental spinal stenosis on imaging in a patient who complains of back pain is fairly good. However, spinal stenosis is usually not the cause of isolated back pain; it causes symptoms of neurogenic claudication (pain, numbness, heaviness in the thighs and perhaps lower legs with standing and ambulation, which is relieved by sitting down). References AHRQ Report: Treatment of Degenerative Lumbar Spinal Stenosis. Summary, Evidence Report/Technology Assessment: Number 32. AHRQ Publication No. 01-E047, March 2001. Agency for Healthcare Research and Quality, Rockville, MD. http://www.ahrq.gov/clinic/epcsums/stenosum.htm Atlas SJ, Deyo RA. Evaluating and managing acute low back pain in the primary care setting. Journal of General Internal Medicine. 2001;16:120-131. Atlas SJ, Nardin RA. Evaluation and treatment of low back pain: an evidence-based approach to clinical care. Muscle and Nerve. 2003;27:265-284. Borenstein DG, O’Mara JW Jr, Boden SD, Lauerman WC, et al. The value of magnetic resonance imaging of the lumbar spine to predict low-back pain in asymptomatic subjects : a seven-year follow-up study. Journal of Bone and Joint Surgery of America. 2001;83-A:1306-1311. Frymoyer JW, Newberg A, Pope MH, Wilder DG, et al. Spine radiographs in patients with low-back pain. An epidemiological study in men. Journal of Bone and Joint Surgery of America. 1984;66:1048-1055. Jarvik JG. Imaging of adults with low back pain in the primary care setting. Neuroimaging Clinics of North America. 2003;13:293-305. Jarvik JG, Deyo RA. Diagnostic evaluation of low back pain with emphasis on imaging. Annals of Internal Medicine. 2002;137:586-597. Jensen MC, Brant-Zawadzki MN, Obuchowski N, Modic MT, et al. Magnetic resonance imaging of the lumbar spine in people without back pain. New England Journal of Medicine. 1994;331:69-73. Kendrick D, Fielding K, Bentley E, Kerslake R, et al. Radiography of the lumbar spine in primary care patients with low back pain: randomised controlled trial. British Medical Journal. 2001;322:400-405. North American Spine Society. Unremitting Low Back Pain. LaGrange, IL: North American Spine Society (NASS), 2000. p. 23. (http://www.spine.org/guidelines.cfm) Phillips RB, Frymoyer JW, Mac Pherson BV, Newburg AH. Low back pain: a radiographic enigma. Journal of Manipulative Physiology and Therapy. 1986;9:183-187. Porter RW, Bewley B. A ten-year prospective study of vertebral canal size as a predictor of back pain. Spine. 1994;19:173-175. Rao JK, Kroenke K, Mihaliak KA, Eckert GJ, Weinberger M. Can guidelines impact the ordering of magnetic resonance imaging studies by primary care providers for low back pain? American Journal of Managed Care. 2002;8:27-35. Suarez-Almazor ME, Belseck E, Russell AS, Mackel JV. Use of lumbar radiographs for the early diagnosis of low back pain. Proposed guidelines would increase utilization. JAMA. 1997;277:1782-1786.