ADVANCING YOUR PRACTICE

Is low back pain getting on your nerves?
 By Yvonne D’Arcy, CRNP, CNS, MS

Low back pain is a very common patient complaint. The back is one of the most integral structures of the body, providing support for muscles and tendons while protecting the spinal cord. Because it’s the foundation of the body's support, it’s subject to wear and tear from overuse, incorrect use, disease, the aging process, and obesity. Any of these can cause deterioration of the vertebral bodies and disks, resulting in low back pain.

A 2002 study reported that 26% of respondents experienced low back pain during a 3-month period.1 Nonspecific low back pain is the fifth most common reason for healthcare provider visits in the United States.2 It isn’t only causes pain and suffering for patients, but depletes healthcare resources. Correspondingly, the costs of time lost from work and disability reach into the millions of dollars. Proper treatment of back pain can include medication, exercise, or even surgery.

Patients at risk
The pain and disability of low back pain are the most common reasons patients seek healthcare.3 The condition can be caused by a number of factors, including arthritis, aging, normal wear and tear, degeneration, arthritic bone spurs, structural damage, or a malignancy.4 Risk factors that predispose patients to low back pain include the following:

  • poor physical condition without a regular exercise regimen
  • age over 55 years
  • lifting heavy loads or engaging in daily hard physical labor
  • obesity
  • reduced spinal canal dimensions (spinal stenosis)
  • lower socioeconomic status (less access to healthcare).4-6

Workers who sit at desks for long periods of time or stand all day may find that low back pain can be a life-altering condition. Quality of life is heavily affected by chronic low back pain, as pain may interfere with the ability to work, sleep, and maintain relationships.

As the U.S. population ages, the prevalence of low back pain resulting from degenerative changes seen in these patients will increase. There are 89 million baby boomers who are at risk for degenerative disk disease (DDD).7 A high prevalence of arthritis will contribute to a large number of patients with low back pain from facet disease and bone spurs.

The spine and common spinal conditions
The spine consists of vertebral bodies and disks. The vertebrae are divided into three major sections: cervical, thoracic, and lumbar. There are seven cervical vertebrae, identified as C1 through C7; 12 thoracic vertebrae, identified as T1 through T12; and five lumbar vertebrae, identified as L1 through L5.

Below the lumbar vertebrae are the sacrum, consisting of five fused vertebrae, and the coccyx with four fused vertebrae.8 The spine has normal curvatures at the cervical and lumbar area. Proper posture maintains spinal alignment and can decrease the possibility of low back pain. The vertebral body has a central canal for the spinal cord and transverse processes where the spinal nerve roots are located.

Each vertebra has a vertebral body that’s separated from the adjacent vertebra by a soft, fluid-filled gelatinous disk.8 This disk acts as a cushion for mechanical stress and gives the spine its flexibility. It also maintains support and posture. Each disk is surrounded by a fibrous envelope, known as the annulus, that consists of 12 concentric layers of fibrous tissue. This tissue helps secure the disk in place.

The aging process has an acute effect on these disks. By age 20, the vascularity of each disk decreases, and by age 30, the desiccation of the disk can cause fissures in the vertebral body endplates. This leads to DDD, which isn’t so much a disease, but part of the aging process.7 As degenerative changes take place and each disk becomes less supple, compression can cause the disk to rupture through the annulus, resulting in a herniated disk. This can be extremely painful since the nerve root can be impinged leading to radiculopathy.6 Patients with DDD develop vertebral osteophytes; this condition is called spondylosis.7 The disk becomes flatter, cracks develop, and the vertebra develop roughened edges where osteophytes (bone spur type formations) form. It can also affect the facets of the spine and develop into facet disease.

Two other spinal conditions can cause low back pain. Spondylolysis is a defect in the vertebral arch caused by mechanical stress. This injury is found in children who participate in gymnastics and other sports, such as wrestling or football, where hyperextension of the spinal body is possible.7 The damage in the posterior part of the vertebra causes the vertebral body to become malpositioned, generally in the lumbar spine. Because of the malpositioning, the patient will present with constant low back pain—there may also be motor or sensory loss at L4-5 and S1. Spondylolisthesis is a subluxation of the lumbar vertebrae where one vertebra overrides the lower vertebra. It can present with severe pain and radicular symptoms, bowel or bladder dysfunction, and weakness in the lower extremities.

Older patients with osteoporosis may experience vertebral compression fractures. These compression fractures are extremely painful as the nerve root of the vertebral body is compressed. Osteoporosis causes the vertebral bone to become porous and prone to fracture. Older patients also experience desiccation of the vertebral disks, which destroys the cushioning function.

It’s estimated that 95% of the population will have DDD by age 50.7 Patients with DDD present with deep midline low back pain that can radiate to buttocks or thighs. There may be motor weakness, sensory changes, absent or diminished reflexes, and, in more severe cases, bowel or bladder dysfunction.8 Patients with spinal stenosis and herniated disks account for 3% to 4% of low back pain patients; cancer, 0.7%; and compression fractures, 4%.2

Diagnosing low back pain
The American College of Physicians and the American Pain Society have developed a joint guideline for diagnosing and treating low back pain.2 The first guideline recommendation requires a complete focused history and physical exam. A focused history and physical exam can indicate the frequency of symptoms, location and duration of the pain, history of the pain, and prior treatment. Information about any concurrent infection or neurologic symptoms such as numbness or muscle weakness should also be investigated.

The physical exam should include the straight leg raise to determine if a disk is herniated. Since most herniated disks occur in the lumbar spine, this diagnostic tool, along with a neurologic exam that includes great toe and foot dorsiflexion, plantar dorsiflexion, and ankle reflexes, can identify the area of pain. Practitioners should look for the patient to experience pain when the leg is at a 30 to 70 degree increase, as that range affects the nerve roots.2

This information can be used to categorize patients in one of the following groups: nonspecific low back pain, back pain potentially associated with radiculopathy or spinal stenosis, or back pain potentially associated with another spinal cause.2 Practitioners should also assess for psychosocial risk factors (for example, depression, lack of coping skills, anxiety disorder, and substance abuse disorder) that could predict the risk for chronic disabling back pain. This assessment is more predictive of the outcome of treatment than the physical exam or the pain severity or duration.

The second recommendation states that clinicians should try to avoid imaging or other diagnostic tests in patients with nonspecific low back pain.2 Rationale for this recommendation includes the exposure of patients to unnecessary radiation in the lumbar and lower abdominal area of the body. The use of plain radiography and advanced imaging with computerized tomography (CT) or magnetic resonance imaging (MRI) have not been associated with improved patient outcomes. For the majority of patients with nonspecific back pain, the use of imaging creates increased exposure to radiation, increased cost of treatment, and does not positively affect treatment outcome.

The third recommendation indicates instances where imaging should be used.2 Patients who have severe or progressive neurologic deficits or those in which serious underlying conditions are suspected should have diagnostic imaging and testing. Conditions that merit immediate imaging include cancer with suspected cord compression, vertebral infection, and cauda equina syndrome. MRI is preferred over CT because it allows better visualization of the spinal structures. MRI can detect annular tears and disk fragments, and is helpful in identifying cancer and infection.

The fourth recommendation states that those who present with persistent low back pain and signs and symptoms of radiculopathy or suspected spinal stenosis should be evaluated using an MRI, the preferred imaging study, or CT only if the patient is a candidate for surgery or epidural steroid injection.2

In addition to diagnosing the physical injury, practitioners should be aware that depression is common in patients with chronic pain, and the rate of suicide in patients with chronic pain is twice the rate of patients without pain.9 Practitioners should assess patients' moods at each visit, and explain to them that depression is not uncommon for those with chronic pain.

Pharmacologic treatment options
Acute low back pain generally resolves within 6 to 12 weeks, regardless of treatment.10 The 15% of patients with acute low back pain who don’t improve within that time period are considered to have chronic low back pain.3 Treatment approaches differ, depending on the severity of back pain.

Medications are the first line of pain management for most patients, but the challenge is: Which medication and for how long? In a recent study, 80% of primary care patients who complained of low back pain were prescribed at least one medication at the initial office visit; more than one-third were prescribed two or more.11

  • Acetaminophen. One of the most common medications patients use at home and that’s recommended by clinicians is acetaminophen. It has minimal risk when taken in dosages lower than the recommended adult maximum dose of 4,000 mg/day. Doses of 4,000 mg/day can result in asymptomatic elevations of liver function tests even in healthy adults, but the risk profile to these increases has not been clearly identified.11 Even though acetaminophen is less effective than nonsteroidal anti-inflammatory drugs (NSAIDs), it’s still worth considering as a firstline option because of its low cost and low risk profile.
  • NSAIDs. There are two different types of NSAIDs: NSAIDs that affect both COX 1 and COX 2 prostaglandin production and COX 2 medication that’s COX 2 selective and doesn;t affect the COX 1 prostaglandins that protect the stomach lining. The COX 2 medications are prescription-only, but nonselective NSAIDs are available over the counter.

The risk-benefit profile is a concern when using NSAIDs to treat low back pain. Both types of NSAIDs can increase cardiovascular risks and renovascular events. Nonselective NSAIDs have an increased risk of ulceration and gastrointestinal (GI) bleeding (using aspirin with NSAIDs can increase the risk for GI bleeding).5 NSAIDs should be prescribed at the lowest dose for the shortest period of time.2

  • Opioid analgesics. The third recommendation for medication is an opioid analgesic or tramadol. These medications should be prescribed for patients who have failed to obtain relief with acetaminophen or NSAIDs. Pain should be severe or disabling before opioids are considered for treatment.3 In the short term, they may be efficacious, but long-term benefit is less clear.12 The incidence of substance abuse is high, with a finding of aberrant medication disorder occurring in up to 24% of patients.12 In a study of 800 patients treated in primary care practices for chronic pain and prescribed opioids, the addiction rate was about 4% for patients who had been exposed to opioids or had a history of substance abuse.13

Another unfortunate occurrence is the development of opioid-induced hyperalgesia. This condition is an atypical hyperalgesic state where pain severity is increased dramatically unrelated to the original pain stimulus.14 The syndrome is thought to be caused by long-term use of opioids that create pain generation in the central nervous system and no longer require nociceptive input to create pain.

  • Other medications. Other medications can be used alone or in conjunction with primary pain management regimens. These include antidepressants, antiseizure medications, muscle relaxants, benzodiazepines, and steroids.

Nonpharmacologic interventions
When patients don’t show improvement with standard treatment, evidence-based nonpharmacologic therapies should be added to the medication regimen. Acute low back pain, which has been present for less than 4 weeks, may benefit from spinal manipulation or superficial heat. Exercise therapy, both supervised and at-home regimens, hasn’t proved effective for acute low back pain.2

Subacute low back pain, which has persisted between 4 and 8 weeks, may benefit from interdisciplinary rehabilitation that includes a physician, NP, and nurses; physical therapy; psychological, social, and vocational intervention; or cognitive behavioral therapy. Chronic low back may benefit from acupuncture; exercise prescribed by a physical therapist, massage, or yoga; progressive relaxation in which the patient relaxes various areas of the body, from head to toe in sequence; spinal manipulation; and interdisciplinary rehabilitation that uses many different disciplines such as nursing, medical, physical therapy, psychology, etc.2, 15-17

Surgical options for treating vertebral fractures include vertebroplasty, which repairs and strengthens the vertebra; and kyphoplasty, which repairs the vertebra and corrects the curvature of the spine. In a review of vertebroplasty and kyphoplasty, 85% of the patients who underwent vertebroplasty and 92% of patients who underwent kyphoplasty reported good pain relief with the procedure.18

There’s conflicting and insufficient evidence related to the use of epidural or other injections for relieving low back pain.19 Prolotherapy, the injection of irritant solutions into weakened back muscles, doesn’t have evidence to support its use alone; however, when added to a comprehensive regimen of rehabilitation, the injections were more effective than control injections.20

Educating patients
Discuss medication options with patients carefully. Many patients with chronic pain rely only on medication to manage pain. It’s important to see medication as a part of the treatment regimen rather than the only option. All patients with chronic low back pain should be encouraged to use a multimodal approach to managing their condition.

In the acute phase, remaining active, using heat, and medication, such as acetaminophen and NSAIDs, will produce the best outcome. If the pain persists, a rehabilitation program and relaxation can provide benefit.

For chronic pain, the combination of medication and complementary techniques provide the best outcome. If pain is severe or disabling, opioids may be an option. Yoga and exercise can help increase flexibility in tense muscles. Using different types of exercise therapy can be helpful, such as exercise classes, swimming, or water therapies. Teaching patients to use relaxation techniques can help them conquer feelings of helplessness and decrease stress.

Encourage patients to stay as active as possible, and help them choose pain management that fits their lifestyle. For example, yoga and massage may not be realistic options for all patients. Relaxation, stress relief, and meditation can help build useful coping skills.

References
1. Deyo RA, Mirza SK, Martin BI. Back pain prevalence and visit rates: estimates for U.S. national surveys, 2002. Spine. 2006;31(23):2724–2727.
2. Chou R, et al. Diagnosis and treatment of low back pain: a joint clinical practice guideline from the American College of Physicians and the American Pain Society. Ann Intern Med. 2007;147(7):478–491.
3. Von Korff M, Saunders K. The course of back pain in primary care. Spine. 1996;21:2833–2837.
4. D'Arcy Y. Pain Management: Evidence-Based Tools and Techniques for Nursing Professionals. Marblehead, MA: HcPro; 2007.
5. Dorsi MJ, Belzberg AJ. Low back pain. In: Wallace MS, Staats P, eds. Pain Medicine & Management. New York: McGraw-Hill; 2005.
6. D'Arcy Y. Low back pain relief. Nurse Pract. 2006;31(4):17–25.
7. Lower S. Oh my aching back. Paper presented at: Nursing 2008 Symposium Conference; March 2008; Las Vegas, NV.
8. Smeltzer S, et al. Textbook of Medical Surgical Nursing. Philadelphia, PA: Wolters Kluwer, Lippincott Williams and Wilkins; 2008.
9. Tang NK, Crane C. Suicidality in chronic pain: a review of prevalence, risk factors, and psychological links. Psychol Med. 2006;36(5):575–586.
10. Hagan KB, Hilde G, Jamtveldt G, et al. Bed rest for acute low back pain and sciatica. Cochrane Database Syst Rev. 2005;(4):CD001254.
11. Chou R, Huffman L. Medications for acute and chronic low back pain: a review of the evidence for an American Pain Society/American College of Physicians Clinical Practice Guideline. Ann Intern Med. 2007;147(7):505–514.
12. Martell B, O'Connor P, Kerns R, et al. Systematic review: opioid treatment for chronic back pain: prevalence, efficacy, and association with addiction. Ann Intern Med. 2007;146(2):116–117.
13. Flemming M, Balousek S, Klessig C, et al. Substance abuse disorders in primary care sample receiving daily opioid therapy. J Pain. 2007;8(7):573582.
14. DuPen A, Shen D, Ersek M. Mechanisms of opioid-induced tolerance and hyperalgesia. Pain Manag Nurs. 2007;8(3):113121.
15. Chou R, Huffman L. Nonpharmacologic therapies for acute and chronic low back pain: a review of the evidence for an American Pain Society/American College of Physicians clinical practice guideline. Ann Intern Med. 2007;147(7):492–504.
16. Khadlikar A, et al. Transcutaneous electrical nerve stimulation (TENS) for chronic low back pain. Cochrane Database Syst Rev. 2005;(3):CD003008.
17. Manheimer E, et al. Meta-analysis: acupuncture for low back pain. Ann Intern Med. 2005:142(8):651–663.
18. Hulme P, Krebs J, Fergusson S, et al. Vertebroplasty and kyphoplasty: a systematic review of 69 clinical studies. Spine. 2006;31(17):1983–2001.
19. Marcus A. APS Guidelines for low back pain show little love for interventional therapies. Pain Medicine News. 2008;6(6).
20. Yelland M, et al. Prolotherapy injections for chronic low back pain: a systematic review. Spine. 2004;29(1):21262133.

Source: Nurse Practitioner. May 2009.
     
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