Low Back Pain

Overview

Low back pain is the second most-common reason patients visit a doctor, and approximately 80% of the U.S. adult population will suffer an acute episode of disabling back pain in their lifetime. In addition, back pain is the most common cause of disability for patients under 45 years of age. However, less than 7% of the population will develop recurrent or chronic back pain, and less than 1% will require back surgery.

Causes

There are many causes of low back pain, which can be categorized as mechanical, degenerative, inflammatory, infectious, traumatic, oncologic (tumor or cancer), congenital/developmental, idiopathic, or psychogenic. Within each of these categories, there are a number of specific diagnoses that can cause back pain with or without associated symptoms. Despite back pain being so common, the precise etiology is not determined in greater than 80% of cases. This may be, in large part, due to the fact that most patients have improvement of their pain before visiting their physician and/or obtaining diagnostic tests. Although there are numerous causes of back pain, it is imperative to distinguish whether the pain is actually generated by a primary spinal problem, or whether it is caused by some other body system (kidney disorder, aortic aneurysm, etc.) mimicking back pain.

Symptoms

Although most patients with a spinal disorder present with some degree of axial back pain, this may not be the chief complaint or problem. Patients with a simple muscle strain or lumbar ligament sprain will often have only isolated back pain and spasm, whereas a patient with a large herniated disc with spinal nerve compression may have severe radiating leg pain with little or no back pain. Patients with spinal stenosis may have aching pain, weakness, and numbness in the buttocks and thighs when walking. Spine infections or tumors may present with constitutional symptoms such as fever, chills, weight loss, and/or night pain. Patients with rheumatoid arthritis or other inflammatory conditions may have multiple areas of musculoskeletal pain, swelling, stiffness, and deformity.

Physical Findings

The physical findings for most spinal disorders often include localized tenderness and decreased trunk range-of-motion. Skin lesions or wounds, swelling, or ecchymosis (bruising) are typically seen only with traumatic injuries, infections, or possibly tumors. Neurologic abnormalities (such as leg muscle weakness or numbness) may be present with a variety of serious spinal disorders, and indicate significant spinal cord or nerve root compression. Abnormal balance or coordination when standing and walking can signify significant disorders of the spinal cord or brain. Sudden onset of bowel or bladder dysfunction can also be indicative of spinal cord compression.

Imaging Studies

X-rays are commonly obtained in the early phases of back pain evaluation, especially if the pain began suddenly or occurred because of a traumatic injury. X-rays of the spine are simple, cost-effective imaging tests that can be used to evaluate bone quality (checking for osteoporosis), spinal alignment, and check for a spine fracture. A magnetic resonance imaging (MRI) study is routinely ordered to evaluate for a disc injury, spinal cord/nerve compression, or spinal tumor or infection. A Computed Tomography (CT) scan is used to more accurately identify and diagnose bone lesions. A myelogram may be performed by itself or in conjunction with a CT scan to evaluate neurologic compression, and involves injecting dye into the spinal canal (within the thecal sac, where the nerves are contained) and taking x-rays and/or CT images of the spine afterward. A bone scan is a special test that utilizes a radionucleotide tracer, which is injected intravenously, to help identify bone lesions such as cancer, tumors, infections, or fractures. A bone density test is noninvasive and checks the mineral density of bone (usually of the spine, hip, and wrist areas) to determine if osteoporosis is present.

Laboratory Tests

Simple blood tests may also be useful in the evaluation of back pain. A Complete Blood Count with differential (CBC), erythrocyte sedimentation rate (ESR), and C-Reactive Protein (CRP) is ordered if infection is suspected. Calcium, Phosphorus, Vitamin D, Parathyroid Hormone, and Alkaline Phosphatase levels are checked when metabolic disorders are suspected. Titers for Rheumatoid Factor (RF), ANA, and HLA-B27 are checked when the patient is suspected of having rheumatoid arthritis, ankylosing spondylitis, or other rheumatologic disorder. Serum Protein Electrophoresis and Urine Protein Electrophoresis is performed to detect multiple myeloma, the most common type of bone cancer of the spine.

Electrophysiology tests such as electromyelography and nerve conduction (EMG/NCV) studies are routinely performed by a neurologist to distinguish the precise location and severity of nerve damage.

Diagnosis

Mechanical Strain, Sprain, Annular Tear, Herniated Nucleus Pulposis
Degenerative Degenerative Disc Disease, Facet Arthropathy, Spinal Stenosis
Inflammatory Rheumatoid Arthritis, Ankylosing Spondylitis
Infectious Discitis, Osteomyelitis, Epidural Abcess (Pyogenic, Tuberculous, Fungal)
Traumatic Fracture, Subluxation, Dislocation
Oncologic Benign or Malignant Spine Tumor, Metastatic Spine Tumor
Congenital Scheuermann's Disease, Scoliosis
Idiopathic Unknown
Psychogenic Psychiatric Disorders with manifestation of back pain

A differential diagnosis (list of possible diagnoses) is developed before, and especially after, all of the symptoms, physical findings, imaging studies, and laboratory tests are analyzed. Often, there is one diagnosis that can be firmly established if all of the appropriate examinations and studies were performed.

Treatment Options

Treatments for low back pain, like many medical conditions, can be conservative (non-operative) or surgical. Most conditions affecting the spine are self-limited, and improve or completely resolve with conservative treatments. Patients are generally recommended for the most conservative, noninvasive treatments first. Spinal injections and surgical treatments are only considered if the diagnosis is amenable to surgery and non-operative treatments have failed. Rarely, some spinal conditions are more serious (fractures, cancer, etc.) and require immediate surgical management.

Conservative

  • Rest or Activity Reduction
  • Oral Medications
  • Topical (Ice packs, heat, ointments, etc.)
  • Orthotics (Back brace, corset, etc.)
  • Yoga or Pilates exercises
  • Massage
  • Physical Therapy
  • Chiropractic Manipulation
  • Modalities (Ultrasound, Phonophoresis, Iontophoresis)
  • Sauna or Whirlpool
  • TENS
  • Interferential Unit
  • Traction
  • Acupuncture
  • Facet Joint Injections
  • Epidural Steroid Injections

Surgical

  • MicroLumbar Discectomy
  • MicroEndoscopic Discectomy
  • Laser Discectomy
  • MicroLaminectomy
  • MicroForaminotomy
  • Laminectomy
  • Posterior Lateral Fusion
  • Posterior Lateral Fusion with Instrumentation
  • Posterior Pedicle Subtraction Osteotomy
  • Anterior Lumbar Discectomy and Fusion
  • Anterior Lumbar Corpectomy
  • Artificial Disc Replacement

Selected Bibliography

Frymoyer JW. Back Pain and sciatica. N Engl J Med 1988;318:291.

Kelsey JL, White AA III. Epidemiology and impact of low back pain. Spine 1980;5:133.

Murray PM, Weinstein SL, Spratt K. Natural history and long term follow-up of Sheuermann's kyphosis. J Bone Joint Surg 1993;75A:236.

Rothman RR, Simeone FA. The spine. Philadelphia, WB Saunders, 1999.

Weber H. Lumbar disc herniation: a controlled prospective study with 10 years of observations. Spine 1983;8:131.

Weinstein JN, Wiesel SW. Lumbar spine. Philadelphia, WB Saunders, 1990.