Learning Objectives: After participating in this continuing professional development activity, the provider should be better able to:
1. Identify the most common causes of back pain in the elderly population.
2. Explain the principles of back pain management in geriatric patients, including pharmacologic and nonpharmacologic nonoperative and surgical considerations.
Back pain is the second leading reason for which patients of all ages seek care, and the elderly population is particularly affected with functional limitations and disability.1 Low back pain is defined as pain or discomfort that occurs below T12 and above the gluteal sulcus, and it is occasionally associated with radiating leg pain.1 Unlike younger individuals afflicted with low back pain, the elderly population requires additional considerations when determining an appropriate treatment strategy for remedying back pain. A study evaluating the prevalence of co-occurring pain sites among older adults with back pain and their impact on longitudinal outcomes determined 93% of respondents had at least one additional pain site, whereas 69% reported multiple pain sites, and that an increasing number of pain sites were associated with worse long-term disability, pain intensity, health-related quality of life, and increased risk of falls.2 This phenomenon may, therefore, limit the potential for improvements after surgery, thus requiring nonoperative alternatives to alleviate back pain in older adults. This review details the epidemiology, common causes, and treatment options for the management of chronic back pain in the elderly.
Epidemiology
Between 60% and 85% of all adults experience chronic back pain over the course of their lifetime.3 Many risk factors for developing chronic low back pain have been identified, including age-related changes in supraspinal pain processing, vigorous physical activity, female sex, lower socioeconomic status, lower educational levels, and smoking.4 The majority of low back pain that occurs, regardless of age group, is diagnosed as nonspecific low back pain-meaning that no discrete pathology can be identified.4
Although psychosocial comorbid conditions such as loneliness, economic difficulty, poor self-related health, and dependence with activities of daily living have been identified as risk factors, general medical comorbid conditions including obesity, hypertension, and joint pain have been identified as predictors of developing chronic lower back pain in the elderly.5 Beyond that, elderly populations may demonstrate some level of cognitive impairment due to dementia, prior strokes, or simply age-related memory loss, which places them at increased risk for undertreatment of their pain.6
Overall, this population is particularly at risk for alterations in mental status, which can lead to deficits in communicating level of pain; contraindications, which can limit treatment and management plans; and psychosocial comorbid conditions, which can negatively affect patients' recovery and attitudes toward their condition.7 At best, these factors make treating chronic lower back pain in the elderly challenging, and, at worst, may potentiate their pain and further worsen their condition.
Causes of Chronic Back Pain
Lumbar Degenerative Spondylolisthesis
Lumbar degenerative spondylolisthesis is a common source of lower back pain and is defined as when a cephalic vertebra slips, either forward or backward, over a caudal vertebra secondary to a degenerated disc and facet joint arthrosis.4 The prevalence of spondylolisthesis in elderly adults in the United States is as high as 30%.8 Patients typically present with symptoms of mechanical low back pain, radiculopathy, or neurogenic claudication.8 The detection of spondylolisthesis can be done using lateral radiographs.8 Although this diagnosis is common, the link between low back pain and a degenerative spondylolisthesis is less clear.
Lumbar Spinal Stenosis
Lumbar spinal stenosis is defined as narrowing of any part of the spinal canal that places pressure on the dural sac and nerve roots and is one of the most common causes of low back and leg pain in the elderly.9 This condition can occur with or without spondylolisthesis and is often accompanied by facet hypertrophy and thickening of the ligamentum flavum.4 No gold standard for diagnosis is agreed upon; however, a combination of key findings on clinical examination and imaging is used to make the diagnosis. Patients will typically report bilateral leg or buttock pain when standing or walking that is only relieved by sitting or leaning forward. An MRI without contrast likely shows narrowing of the spinal canal or the presence of nerve root compression. Similar to degenerative spondylolisthesis, spinal stenosis is a common finding in advanced imaging, but the link between stenosis and back pain is less clear. Typically, symptomatic stenosis results in neurogenic claudication or radicular symptoms.
Infection
Vertebral osteomyelitis (VO) is a common cause of chronic low back pain and is one of the most common infectious diseases among the elderly population.4 Four possible etiologies for the development of VO have been proposed: (1) gram-positive bacteria that can be disseminated hematogenously and form microabscesses at the metaphyseal arterioles; (2) patients who have contracted Mycobacterium tuberculosis early in life may retain bacteria in the vertebral bone only to later reactivate due to age-related decreases in immune function; (3) aerobic gram-negative bacteria in older men with urinary tract infections may seed the spine through the prostatic venous plexus; and (4) iatrogenic infections can occur as a result of spinal surgeries or procedures.4
Myofascial Pain
Myofascial pain in the piriformis or lumbar muscles is common among the elderly. It is due to muscles resisting passive stretching, thereby producing a localized tenderness and palpable nodule that is painful on palpation.4 Although evidence is sparse, it is believed myofascial pain develops after muscle overuse due to a combination of eccentric overload, submaximal concentric contractions, and local ischemia.10
Spinal Deformity
Deformities of the adult spine can result from degenerative disc disease, rheumatoid arthritis, congenital deformity, trauma, infection, or iatrogenic pathologies.11 Elderly adults may present with worsening of idiopathic scoliosis that developed during adolescence, or de novo degenerative lumbar scoliosis resulting in sagittal or coronal plane deformities. Degenerative lumbar scoliosis is defined as a coronal plane curve with a Cobb angle greater than 10 degrees. It typically develops after 50 years of age in patients with no history of scoliosis and is thought to have a prevalence as high as 68% of the population older than 60 years.4 Sagittal plane deformities are a significant generator of chronic back pain and contribute to disability among older patients. These deformities can be the result of age-related degenerative changes or from an iatrogenic cause, after lumbar spine fusion without restoration of lordosis. Patients typically present with chronic back pain, overt deformity on examination, and neurogenic claudication.11 These patients can exhibit severe disability and become very limited with daily activities.
Sacroiliac Joint Dysfunction
Nonspecific lower back pain also has the potential to originate from sources outside the lumbar spine, such as the sacroiliac region. Sacroiliac joint (SIJ) dysfunction often presents as a localized lower back pain and has the potential to involve a radiating posterior thigh pain, which often remits when lying down.4 It has been estimated that the SIJ may be the source of the pain in 15% to 30% patients presenting with lower back pain.12
Hip Osteoarthritis
Similarly, osteoarthritis of the hip can also be an extraspinal confounding source of nonspecific lower back pain. One in 2 people with hip osteoarthritis reports concomitant low back pain, and 1 in 4 older adults may have physical examination findings indicative of hip osteoarthritis-a condition that often presents with pain in the groin, buttocks, thigh, and/or distal lower extremity and may be misinterpreted by the patient as emanating from the lower back.13 Risk factors for developing hip osteoarthritis include age, preexisting hip dysplasia, prior hip trauma, femoroacetabular impingement, socioeconomic status, higher bone mass, and higher body mass index.13
Neoplasm
Cancer is a rare cause of lower back pain, typically manifesting as progressive, unremitting pain, which is worse at night and not eased by rest.4 Most often, neoplasms of the spine present as metastases from the lung or breast.14 The spine is the third-most common metastatic site.14 Primary tumors in the spine also can occur; however, they are much more rare. They are more likely to be malignant in the elderly, with the most common examples being chordomas, plasmacytomas (multiple myeloma), and lymphomas.4
Mental Illness
Elderly patients are uniquely at risk for emotional pain due to increased social isolation and bereavement. Studies have demonstrated that depressive symptoms increase the odds of developing disabling lower back pain and vice versa, with nearly 20% of the sample size reporting depressive symptoms.15
Degenerative Lumbar Disc Disease
Although it remains unclear whether degenerative lumbar disc disease causes low back pain, MRI findings suggest disc degeneration is more common in adults with low back pain than in asymptomatic controls.16 Intervertebral disc degeneration encompasses pathologic changes in the vertebral column such as disc desiccation, fibrosis, and narrowing and may commonly result in back pain.3 However, because disc degeneration on MRI is increasingly prevalent with age, radiographic changes may not necessarily compare to similar changes in a younger population. A large proportion of elderly patients with abnormal imaging findings may be asymptomatic.4 Intervertebral discs are posited to undergo a "degenerative cascade" that begins with repetitive microtrauma and the development of circumferential tears that compromise blood supply. This is followed by changes that result in the loss of mechanical integrity and stability, ultimately developing disc space narrowing and fibrosis and the formation of osteophytes.4
Treatment of Chronic Back Pain
Cognitive-Behavioral Therapy
Similar mindful therapies like mindfulness meditation (MM), cognitive therapy, and mindfulness-based cognitive therapy (MBCT) have been used in the attempt to treat low back pain. Although a study reported that MBCT demonstrated improved pain interference, physical function, and a lower likelihood of depression compared with MM, the lack of a traditional control makes interpreting the results difficult.17
Complementary Health Methods
Alternative therapies, outside of traditional medicine, are also used by patients to alleviate pain and therefore need to be addressed. A recent systematic review and meta-analysis demonstrated that tai chi, an ancient Chinese form of mind-body exercise, is associated with improvements in chronic pain for low back pain, osteoarthritis, and osteoporosis compared with other conservative interventions such as education and stretching.18 Acupuncture and thread-embedding acupuncture-in which a piece of polydioxanone suture is inserted into the body and later dissolved-are continuing to be used to treat chronic pain conditions. Although there is a limited body of research on the effects of acupuncture, a retrospective chart review demonstrated improved Oswestry Disability Index (ODI) scores when using thread-embedding acupuncture combined with conventional acupuncture to treat chronic low back pain.19 However, data regarding these alternative therapies must be taken with caution, as studies with higher levels of evidence such as a meta-analysis by Nascimento et al20 demonstrated that complementary health methods (acupuncture, mindfulness, and yoga) were not able to produce a clinically significant reduction in pain and disability when compared with sham, usual care, or minimal intervention.
Physical Therapy
Physical therapy treatments for chronic low back pain include stretching, strengthening, aerobic conditioning, trunk coordination, and manipulation. Other modalities include ice and heat, ultrasound, and electrical nerve stimulation.21 The effectiveness of physical and occupational therapy is well-documented with regard to chronic musculoskeletal pain; the combination of active exercises and conditioning, supportive therapy aimed at activities of daily living, and modifications to the home are commonly the conservative treatment option of choice and result in beneficial outcomes with regard to pain and patient autonomy.22 Specifically, multidisciplinary rehabilitation has been demonstrated to reduce short- and long-term pain intensity and disability and improve function in individuals afflicted with chronic low back pain.22 In a systematic review and meta-analysis of 43 studies for chronic low back pain, physical therapy was found to be more effective than other conservative treatments.23 Supervised, individually tailored, high-dose stretching and muscle-strengthening programs with home practice were found to be the most effective form of physical therapy.23
Pharmacologic Management
Pharmacologic management is one of the first lines of treatment for low back pain. According to the American Geriatrics Society, geriatric patients with nonmalignant pain should receive standing orders of analgesics (preferably acetaminophen) so that they maintain steady bloodstream concentrations.24 These standing orders help to limit missed doses that may otherwise occur due to comorbid conditions that alter mental status (eg, dementia).
However, if acetaminophen is unable to control the patient's pain, nonsteroidal anti-inflammatory drugs (NSAIDs) or nonacetylated salicylates may be used as an adjunct therapy.24 Caution must be employed when prescribing these adjunct medications, as NSAIDs may cause gastrointestinal upset; in patients with a history of peptic ulcer disease, nonacetylated salicylates should be preferentially prescribed.4 Other possible adverse effects include renal failure, myocardial infarction, stroke, and hemorrhage.25
Tramadol, a low to moderate opioid receptor agonist, can be used as well, but physicians should be aware of the drug's potential to lower the seizure threshold in particular individuals and therefore should not prescribe it to patients with a history of epilepsy or known seizure risk.24 Opioid medication can be used in the geriatric population but should be slowly titrated up to the patient's need, as opioids have the potential to increase fall risk, confusion, and depressive side effects.26 Ideally, a multimodal protocol can be established with 2 or more of these medications, with different mechanisms of action should be used at the lowest possible doses to both appropriately treat the patient's pain and avoid side effects.4
Polypharmacy is also a concern when dealing with an older population, as patients may be on several other medications concurrently due to their medical comorbid conditions. These medications may complicate pain management due to drug-drug interactions or simply due to the side effect profiles that accompany them. Specifically, fall risk is increased when the patient is taking drugs such as antiarrhythmics, antidepressants, antiepileptics, antiparkinsonian drugs, antipsychotics, benzodiazepines, diuretics, opioids, and urological spasmolytics.26 Common drug-drug interactions include concurrent tramadol and selective serotonin reuptake inhibitor use, which increases the risk of serotonin syndrome; a history of alcohol abuse, which increases the risk of opioid overdose; or opioids and benzodiazepines, which can dramatically affect memory, cognition, alertness, and motor coordination.4
Facet Injection
Intra-articular facet joint injections are widely used in the United States despite no current guideline support for their use in treating low back pain.27 The efficacy of facet injections to treat lower back pain has been researched sparsely, and current literature demonstrates mixed outcomes in improving back pain. A meta-analysis reviewing outcomes for low back pain after facet joint injections reported little evidence of improved outcomes versus placebo/sham-controlled procedures. Although facet joint injections may provide relief for a subgroup of patients with specific low back pain, further investigation is needed for establishing their use as an effective therapy.27
Radiofrequency Ablation
Using an electrode with a current of 250 to 500 kHz, radiofrequency (RF) ablation induces ionic movements in the tissue. By ablating nerves in the low back and preventing conduction of nociceptive impulses, a patient may experience pain relief. Although RF ablation has been used for the management of SIJ pain and discogenic pain, it remains unclear whether RF ablation is an effective therapy for the treatment of chronic back pain.28
Spinal Cord Stimulation
Spinal cord stimulation (SCS), which involves electrical stimulation of the dorsal columns of the spinal cord, can be used in the treatment of chronic back pain.29 Recent advancements in SCS, specifically the use of high-frequency SCS (10,000 Hz), have displayed promising improvements from traditional SCS (<1200 Hz). A recent trial compared high-frequency SCS with traditional SCS in patients with back pain for a 12-month follow-up period. Eighty percent of patients in the high-frequency SCS reported reductions in back pain with no stimulation-related neurologic deficit compared with only 50% of patients in the traditional SCS group (Figure 1).29
Surgical Intervention
Surgical interventions are typically reserved for eligible patients who have failed conservative therapies. Surgical approaches often have 1 of 2 goals in mind: fusion or decompression. In cases of symptomatic hip osteoarthritis, total hip arthroplasty is a successful surgical procedure. Spinal fusion seeks to resolve improper alignment or excessive motion by the addition of a bone graft, whereas decompression seeks to correct neural impingement by the removal of the offending vertebral material.3 In general, surgery to correct back pain in the elderly should be limited to instances in which the cause is especially clear, such as metastatic disease with neurologic deficit or degenerative spondylolisthesis with radiculopathy due to the various medical comorbid conditions present within this population that places it at increased risk during surgical procedures. In all cases, surgery should be approached cautiously in the elderly, with goals, risks, and benefits defined clearly before surgery is performed.
Sacroiliac Joint
If conservative treatment options fail to relieve back pain caused by SIJ dysfunction, surgical intervention, specifically SIJ fusion, is an option. A meta-analysis demonstrated that patients undergoing SIJ fusion achieve significant improvements in subjective lower back pain relief, ODI, 36-Item Short Form Health Survey, and Majeed scores.12 Despite this, surgery remains controversial for this diagnosis.
Spinal Deformity
The causation of spinal deformity leading to low pain back can be attributed to degenerative changes, congenital factors, and sagittal deformity. The goals of spinal deformity surgery are to relieve a patient's lower back pain and radicular pain by correcting and stabilizing the spine. These operations can be highly complex, and patients are at high risk of developing minor adverse effects. These operations may involve neurologic decompression, pedicle screw instrumentation, osteotomies or interbody grafts/devices, and stabilization with rods.30
Neoplasms
It is currently recommended that patients with spinal metastases causing symptomatic neurologic compression undergo decompressive surgery before radiation therapy-unless the metastatic cancer is known to be highly radiosensitive, in which case radiation therapy alone is indicated, barring significant neurologic injury.14 The role of surgery may be critical for preventing neurologic compromise; however, it is important to consider end-of-life goals when discussing major surgery in elderly patients with disseminated cancers. In general, surgical interventions are ideal for patients younger than 65 years, with few medical comorbid conditions, an estimated survival time more than 3 months, limited metastatic lesions, and good mobility.14 The older patient with metastatic disease may be at higher risk for postoperative adverse effects, including death.
Conclusion
Management of back pain in the elderly should include thoughtful considerations of a patient's overall clinical picture, cognitive and functional status, and a thorough evaluation of the exact cause of pain-both intrinsic and extrinsic causes. The geriatric patient population often has multiple comorbid conditions that make surgical intervention a risky proposition. Treatment of chronic lumbar back pain in the elderly population should always focus on initial nonoperative management. Physical therapy and closely related alternative therapies are highly recommended strategies for the management of several possible contributors to chronic back pain, including degenerative disc disease, degenerative spondylolisthesis, spinal stenosis, SIJ dysfunction, myofascial pain, and hip arthritis.
Additionally, cognitive-behavioral therapy can improve pain interference, physical function, and depression that may be contributing to pain. Although medication can be effective in treating low back pain, a careful analysis of each medication a patient is prescribed is strongly encouraged; ideally, any prescriptions given to the elderly for symptom relief should be used for the shortest duration and lowest dose required for adequate pain relief. Generally, physicians should first consider analgesics such as acetaminophen. Although NSAIDs and tramadol may be considered if analgesics fail to improve pain, there are risks and possible adverse effects associated with these medications. A physician should also be cognizant of the patient's current prescriptions in efforts to avoid negative drug-drug interactions.
If patients still do not improve, one may suggest more invasive nonoperative treatments-such as SCS, facet injections, and RF ablation-before opting for surgical intervention. Although these treatments have been demonstrated to improve low back pain in some cases, patients should be made aware that pain relief is not always achieved. Those who have failed an initial trial of nonoperative management may be surgical candidates.
Practice Pearls
* Cognitive-behavioral therapy should be considered in patients with possible increased pain associated with depression.
* Physical therapy and closely related alternative practices (tai chi, yoga, etc) are effective nonoperative treatments for chronic low back pain.
* Medicines should be prescribed with care. Acetaminophen is recommended over NSAIDs and tramadol to relieve back pain.
* SCS, facet injections, and RF ablation may be considered, but their efficacy in low back pain is unclear.
References