Lumbar disc herniation is a common cause of chronic or recurrent low back pain. It is most likely to occur at the L4-L5 and L5-S1 levels and upper lumbar levels are involved occasionally.
The incidence of a herniated disc is about 5 to 20 cases per 1000 adults annually and is most common in people in their third to the fifth decade of life, with a male to female ratio of 2:1. The estimated prevalence of symptomatic herniated disc of the lumbar spine is about 1-3 percent of patients. The prevalence is most significant among 30-50-year-olds. The patients between 25-55 years old have an approximately 95 percent chance of herniated discs occurring either at L4-L5 or L5-S1. Disc disease is the underlying etiology in less than five percent of patients with back pain.