Back Pain

Back pain is a ubiquitous complaint and one of the most common reasons for a medical office visit. The differential diagnosis for back pain is very broad. Therefore, a thorough history and careful physical exam are essential for determining the etiology of the back pain. Fortunately, most back pain complaints are benign in nature and responsive to conservative measures alone. However, in the presence [Page 202]of certain symptoms, an aggressive pathology may be suspected; this necessitates urgent evaluation and intervention.

Approximately 75 to 80 percent of individuals experience back pain at some point during their lifetime. Back pain affects both sexes, all age groups, and all socioeconomic classes. Back pain most commonly affects those between 35 and 55 years old and is the leading cause of disability for individuals under 55 years old.

Because of the prevalence and potentially debilitating nature of back pain, it is a major public health concern. Back injuries occur in approximately 2 percent of the U.S. workforce annually, resulting in loss of compensation exceeding $20 billion. In 1998 alone, the healthcare expenditure incurred by low back pain in the United States exceeded $90 billion.

The differential diagnoses for causes of back pain are extensive. The challenge is identifying the cases where further urgent evaluation and intervention are needed. Hence, when assessing for a source of back pain, several important factors should be considered that include a person's age, preceding events, chronicity, location, any radiating pain, additional related symptoms, and even psychological disturbances. Physical exams including thorough systematic assessment of the neurological function of the lower extremities should be performed. Imaging studies, such as conventional radiographs or more advanced radiographic studies, may be employed as well.

One common source of low back pain is a herniated disc. A herniated disc or discs may be due to an acute traumatic event, repetitive use injury, postural problems, or degenerative processes. The disease involves the inner part of the disc (nucleus pulposus) bulging through the surrounding outer ring of the disc (annulus fibrosus). As a result, the extruded disc substance can compress a nerve root (pinched nerve) as it leaves the vertebral column.

Common complaints of herniated discs include radiating back pain and paresthesias that follow the course of the compressed nerve's dermatome. Physical activities or maneuvers that increase the pressure onto the disc, such as coughing, sneezing, and sitting forward can worsen the pain. First-line treatment includes antiinflammatories, activity modifications, and therapy. An individual who does not respond to conservative treatment may be a candidate for invasive measures, such as spinal injections and disc surgery.

Back pain is the fifth leading cause for office visits in the United States and the leading cause of disability for people under age 55.

Another etiology of back pain that should be considered in the differential diagnoses, especially among the elderly, is spinal stenosis. Spinal stenosis is the narrowing of the spinal canal or the opening for an exiting nerve. The narrowing may be congenital or may be acquired, such as from degenerative arthritis. The narrowing causes nerve compression and ischemia. Individuals with spinal stenosis complain of onset of pain, paresthesias, and weakness with walking or standing. Unlike disc herniation, the symptoms in spinal stenosis usually improve with sitting forward because the maneuver increases the diameter of the spinal canal and area of the neural foramen (canal of exiting nerve root). Initial treatment is with physical therapy and antiinflammatories as well. Surgery to widen the canal and decompress the nerve may be indicated [Page 203]for those who do not obtain relief from noninvasive measures.

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