
Back Pain: The Latest in Diagnosis and Management
Acute low back pain affects nearly 80% of the population at some point in their lives. The majority of cases resolve with conservative therapy, including bed rest and mild analgesics. However, acute back pain may occasionally represent serious pathology, such as fracture, infection, or herniation. This slideshow reviews the assessment and management of both common and less common sources of back pain and also features the latest related news and research.
Back Pain: The Latest in Diagnosis and Management
Chronic low back pain (> 3 months) may develop from benign or serious etiologies. Certain clinical features may suggest the need for additional evaluation (ie, blood tests, radiography, MRI, or bone scan), similar to the evaluation of acute low back pain. These "red flags" are somewhat controversial, as most patients with benign causes of back pain may have at least one "flag." However, severe or multiple red flags may prompt additional evaluation.
Back Pain: The Latest in Diagnosis and Management
Pain in the thoracic and cervical regions may stem from acute injury (as in the case above; green arrow shows acute transverse fracture of C2 after a motor vehicle accident, with follow-up images 6 months after surgical repair), paraspinal muscle strain, metastatic disease, infection, underlying mechanical disease, or other serious causes. This slideshow focuses on nonmechanical sources of chronic back pain—specifically, conditions commonly encountered in rheumatologic practice.
Back Pain: The Latest in Diagnosis and Management
SpA, a family of disorders characterized by joint disease of the vertebral column, include ankylosing spondylitis (AS), reactive arthritis, inflammatory bowel disease-associated arthritis, psoriatic arthritis, and undifferentiated SpA. This x-ray shows characteristic AS changes with fusion of the bilateral sacroiliac joints and thin, marginal syndesmophytes spanning the lower lumbar vertebrae's intervertebral disc spaces. Joint involvement in AS typically starts at the sacroiliac joints and ascends caudally. Erosive changes of the symphysis pubis can also be seen.
Back Pain: The Latest in Diagnosis and Management
AS occurs in nearly all patients (95%) by age 40 years. Unlike rheumatoid arthritis (RA), which targets synovial tissue lining the joint capsule, SpA has a predilection for fibrocartilage sites. This x-ray from a patient with AS shows bilateral sacroiliac joint involvement and evidence of syndesmophytes in the lumbar spine. Note the mechanical wires overlying the left lower ribcage; the patient had a pacemaker due to cardiac conduction defects sometimes seen in HLA-B27-positive patients.
Back Pain: The Latest in Diagnosis and Management
The Berlin criteria can heighten suspicion for AS: Three of the four criteria have a specificity of 98%; however, given the low prevalence of AS among cohorts with chronic low back pain (5%), the positive predictive value is only 50%. Berlin criteria are most helpful in identifying high-risk patients who warrant further work-up (eg, HLA-B27 testing) rather than for confirming a diagnosis. ASAS criteria for inflammatory back pain can also be used.
Back Pain: The Latest in Diagnosis and Management
Imaging can help confirm suspicion for AS and other forms of SpA with axial involvement, as outlined in the guidelines above. The x-rays on the following slide show changes of osteoarthritis with horizontally oriented osteophytes. A linear hypodensity seen within the intervertebral disc represents the so-called vacuum phenomenon typically associated with degenerative disease. Intervertebral disc space loss is common in osteoarthritis, as seen in this example, but is not characteristic of axial SpA.
Back Pain: The Latest in Diagnosis and Management
Case 1: Degenerative Disease
A 65-year-old man presented with low back pain. X-ray images showed multilevel degenerative disease with associated scoliosis. In addition, at two levels (green arrows), there was a "vacuum disc" sign, indicating that gas—most often nitrogen—was present in the intervertebral disc space.
Back Pain: The Latest in Diagnosis and Management
This patient had degenerative spine disease and the vacuum phenomenon. Gas can also be present within the vertebral bodies through disc material that herniates in the vertebral bodies (Schmorl nodes) or in the setting of osteoporotic vertebral fractures. Gas may be present in spinal facet joints. Some reports indicate that gas can lead to pressure on nerve structures, leading to clinical symptoms of radiculopathy.
Back Pain: The Latest in Diagnosis and Management
Case 1, Continued
MRI allows detection of early changes, such as bone marrow edema and synovial inflammation. MRI sensitivity and specificity for AS approach 90%; however, the positive predictive value may be as low as 30%. An isolated area of bone marrow edema can be seen in 25% of the general population; therefore, it is proposed to define a positive scan as two separate lesions or one lesion that spans two consecutive slices. The presence of multiple features (eg, bone marrow edema, erosive disease, synovial enhancement) may increase specificity for axial SpA.
Back Pain: The Latest in Diagnosis and Management
Case 2: AS Plus Neuropathy
A 63-year-old man with long-standing AS presented with a 2-year history of lower-extremity neuropathy initially affecting the left leg, then the right leg. Numbness and paresthesia extended to his upper thighs and groin region. Various examinations revealed characteristic lack of mobility at the cervical spine, an inability to touch the back of his head to the wall behind him, decreased range of motion (ROM) at the lumbar spine and no lordosis in that region, suggested as stemming from sacroiliac disease. Neurologic examination was abnormal for decreased sensation of the bilateral lower extremities and saddle anesthesia.
Back Pain: The Latest in Diagnosis and Management
Case 2, Continued
Imaging was obtained and revealed small dural ectasias (outpouchings) with suspected nerve root tethering.
The patient was diagnosed with cauda equina syndrome in the setting of dural ectasia. In AS, this is thought to be due to either: (1) small-vessel vasculitis resulting in direct insult to nerve roots; or (2) chronic arachnoiditis leading to decreased elasticity of the dural sac and impaired cerebrospinal fluid resorption resulting in dural ectasias (with tethering of the nerve roots eliciting symptoms).
Back Pain: The Latest in Diagnosis and Management
Case 2: Treatment
Treatment options (eg, prednisone) in this case are limited. The patient had surgical laminectomy without success, with subsequent development of urinary retention. After he was referred to the rheumatology service, he was given infliximab monthly for 1 year without improvement before therapy was stopped.
Back Pain: The Latest in Diagnosis and Management
The x-rays above show an enlarged interval (6 mm) between the posterior aspect of the anterior arch of C1 and the anterior aspect of the odontoid process (the anterior atlantodental interval; normal ≤ 3 mm). In dynamic extension views, this interval narrows to a normal range. This is suggestive of atlantoaxial instability, often the result of ligamentous injury by RA-related pannus formation.
Back Pain: The Latest in Diagnosis and Management
The T1-weighted image above (left) shows an irregular contour of the odontoid process, with defects along the posterior surface consistent with erosive disease. The rind of soft tissue surrounding the dens represents pannus formation. This tissue shows heterogeneous signal intensity on the T2-weighted image (right), suggestive of synovial hypervascularity in some regions. Atlantoaxial instability can occur in the anterior and posterior planes, and lateral and rotatory instability can also be present. Potentially life-threatening vertical atlantoaxial instability ("cranial settling") can occur. In this case, pertinent measurements should be obtained to determine the likelihood of neurologic compromise.
Back Pain: The Latest in Diagnosis and Management
Case 3: Back Pain With Fever
A 70-year-old man presented with progressive back pain, weight loss, and a low-grade fever. Symptoms were present for 6 months, with progressive worsening despite conservative therapy (ie, anti-inflammatory medications, muscle relaxants). Otherwise, the patient felt relatively well, though he had recently developed leg weakness and urinary retention. Imaging revealed a burst fracture of the L5 vertebrae (top), with extension to structures anterior and posterior to the vertebral body (green arrows), suggestive of an infiltrative process (note the compression of the dural canal). A vertebral bone biopsy revealed no histologic evidence of cancer.
Back Pain: The Latest in Diagnosis and Management
Acid-fast bacteria staining was positive; subsequent cultures revealed Mycobacterium tuberculosis. The patient was started on standard tuberculosis (TB) therapy and eventually underwent stabilization surgery.
TB spinal infection typically involves the vertebral body, with secondary spread to the anterior (green arrow) and posterior longitudinal ligament; further extension up and down the spine along these planes can occur. If involvement is isolated to the vertebral body, cancer should remain high on the differential diagnosis. In contrast, most bacterial infections in the spine start at the intervertebral disc, with secondary extension to adjacent bone.
Back Pain: The Latest in Diagnosis and Management
Case 4: Infectious Discitis?
A 55-year-old woman presented after several years of dull mid-back pain that had progressively worsened. She reported decreased neck ROM without pain for the past 10-15 years and mild pain in the anterior chest with prior suspicion of pleurisy, which had moderately responded to anti-inflammatory medications. She had no constitutional symptoms (eg, fever). The vertebral end plates at T9 and T10 on the above x-ray were markedly irregular with sclerotic borders (green arrow), raising concern about infectious discitis. A biopsy of the disc space and adjacent bone was negative for cancer and infection.
Back Pain: The Latest in Diagnosis and Management
Case 4, Continued
Additional imaging with MRI showed contrast enhancement throughout the T9 and T10 vertebral bodies. Additional areas of enhancement were seen at the T2 and T1 vertebrae. Sternomanubrial enlargement was identified (green arrow). These findings led to imaging of the anterior chest wall, cervical spine, and lumbar spine (next slide). There was extensive bony enlargement of the right clavicle, with concern for cancer, Paget disease of bone, and osteomyelitis. A bone biopsy subsequently grew Propionibacterium acnes. The patient was treated with 6 weeks of intravenous antibiotics and referred to the rheumatology service for further evaluation of the axial spine findings.
Back Pain: The Latest in Diagnosis and Management
Case 4: Diagnosis
Some consider synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO syndrome) to represent a spectrum of the seronegative SpA family. In this case, biopsies overruled initial concerns about infection or cancer. Paget disease of bone was thought less likely, given the normal alkaline phosphatase level and pattern of bone involvement. The absence of skin findings does not preclude a diagnosis of SAPHO syndrome. Additionally, the absence of HLA-B27 and the normal intervening lumbar spine were atypical for AS. Ultimately, the findings of significant clavicular and sternomanubrial hyperostosis, vertebral and iliac bone osteitis (right x-ray), and presence of P acnes were all suggestive of underlying SAPHO syndrome.
Back Pain: The Latest in Diagnosis and Management
Case 5: Skin Disease Plus Back Pain
This 52-year-old man with psoriatic skin disease presented with worsening pain and stiffness in the low back and buttocks, worst in the early mornings and improving after several hours of movement and use of nonsteroidal anti-inflammatory drugs (NSAIDs). Several months ago, he had pain, stiffness, and swelling of his right third proximal interphalangeal joint, which since improved. He had limited ROM of his lower back and a positive FABER test bilaterally. He had scattered psoriatic plaques on his elbows, knees, and scalp. Radiography of the pelvis demonstrated asymmetric sacroiliac joint sclerosis, with near-complete fusion on the right (green arrow). He had mild degenerative disease of both hips. He was diagnosed with psoriatic arthritis with axial involvement. In pure AS, sacroiliac disease is typically symmetric. However, in psoriatic arthritis, sacroiliac involvement can be asymmetric, as in this case.
Back Pain: The Latest in Diagnosis and Management
Case 6: Adolescent Back Pain and Kyphosis
A 14-year-old male presented with back pain and kyphosis. Radiography of the spine demonstrated a wedge-shaped change of the lower thoracic vertebrae (green arrow), with irregular vertebral end plates. This patient had Scheuermann disease, or juvenile osteochondrosis of the spine. The exact cause is unknown but probably due to strain on the vertebral growth cartilage in the appropriate genetic setting. This leads to anterior compression of the vertebra, kyphosis, and clinical symptoms (eg, back pain). Treatment includes physical therapy and bracing, with surgical intervention for severe cases.
Back Pain: The Latest in Diagnosis and Management
Case 7: Back Pain With Calcifications
A 72-year-old man presented with mild low back pain and loss of ROM. On x-ray, he was noted to have flowing calcification of the right side of his spine (green arrows) that was absent on the left side. Diffuse idiopathic skeletal hyperostosis (DISH) was diagnosed (see next slide).
Back Pain: The Latest in Diagnosis and Management
The anterior nature of the calcification can be seen on lateral imaging (see above). The absence of calcification on the left side of the spine as seen in this case has been attributed to the pulsations of the aorta reducing the calcium formation. Radiographic findings in DISH can to some extent mimic those of the spinal disease of AS, but, of note, sacroiliac and facet joint fusion are typically absent. Therefore, diagnosis requires that sacroiliac and facet joint fusion be absent. In addition, the unilateral nature of the calcification was strongly suggestive of DISH and not AS.
Back Pain: The Latest in Diagnosis and Management
Case 8: Postpartum Back Pain
A 28-year-old woman presented with low back and buttock pain 10 weeks after delivery of her first child. X-ray showed triangular sclerosis of the iliac wings at the lower poles of the sacroiliac joints (green arrows), but the sacroiliac joints otherwise appeared normal. Osteitis condensans ilii (OCI), which occurs most in women after birth, was diagnosed.
Back Pain: The Latest in Diagnosis and Management
OCI (left) is characterized on x-ray as triangular sclerosis of the iliac wings in the absence of sacroiliac joint space narrowing or erosions. Radiographic findings may be misinterpreted as inflammatory spinal disease. It can be distinguished from such diseases as (right) by absence of erosive changes or joint-space narrowing in the sacroiliac region. Of note, in inflammatory SI disease, erosions are most commonly seen in the lower third of the SI joint, which is the region that has a synovial lining.
Back Pain: The Latest in Diagnosis and Management
Medscape Medical News has featured several stories on recent back pain research. In 2017, updated guidelines from the American College of Physicians (ACP) recommended conservative back pain treatment, beginning with first-line NSAIDs and muscle relaxers.[1] Elsewhere, a systematic literature review determined that the gabapentinoids pregabalin and gabapentin are not effective in treating lower back pain.[2] In 2016, the US Food and Drug Administration placed a hold on fasinumab, a nerve growth blocker many hoped would be an alternative to opioids for back pain. Although no new breakthrough medications arrived, there is continued evidence to support the efficacy of low-risk lifestyle interventions such as yoga[3] and regular activity[4] like intense walking.
Back Pain: The Latest in Diagnosis and Management
In 2017, an international task force updated their guidelines from 5 years prior, incorporating higher-quality evidence available in the interim. The new guidelines[5] offered stronger support for treating to the target of remission. There were also several recent studies dealing specifically with AS. Results from the MEASURE 1 study[6] showed that secukinumab, a fully human monoclonal antibody against interleukin-17A, improved clinical and radiographic outcomes of AS through 2 years of therapy. Recent findings suggest that biosimilars to infliximab produce comparable outcomes in terms of clinical response and safety. Finally, the use of statins was linked with up to a 60% reduction in premature mortality in patients with AS.[7]
Back Pain: The Latest in Diagnosis and Management
Impact of Back Pain
Advancing the management of back pain and spinal disease is ever-more important in light of the ongoing opioid epidemic in the United States, which has caused many practitioners to ask where to draw the line when treating pain. If not properly treated, back pain can lead to increasingly hazardous situations, which may increase pain. Two recent studies noted that back pain, even in those with no accompanying disabilities, can increase the risk of falling in older men and women.[8,9] This is additionally significant, as back pain is the most common type of pain older men complain of. Identifying the underlying causes of our patients' pain, and treating it as sufficiently as possible may save them from untold problems down the road.
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