Back pain is pain felt in the back. The back is divided into middle back pain (thoracic), lower back pain (lumbar) or coccydynia (tailbone or sacral pain) based on the segment affected. Neck pain (cervical), which is considered an independent entity, can involve similar processes. The lumbar area is the most common area for pain, as it supports most of the weight in the upper body. Episodes of back pain may be acute, sub-acute, or chronic depending on the duration. The pain may be characterized as a dull ache, shooting or piercing pain, or a burning sensation. Discomfort can radiate into the arms and hands as well as the legs or feet, and may include numbness, or weakness in the legs and arms.
The majority of back pain seen in primary care is nonspecific with no identifiable causes. Common identifiable causes of back pain include degenerative or traumatic changes to the discs and facets joints, which can then cause secondary pain in the muscles, and nerves, and referred pain to the bones, joints and extremities. Diseases and inflammation of the gallbladder, pancreas, aorta, and kidneys may also cause referred pain in the back. Tumors of the verteba, neural tissues and adjacent structures can also manifest as back pain.
Back pain is common, with about nine out of ten adults experiencing it at some point in their life, and five out of ten working adults having it every year. Some estimate up to 95% of Americans will experience back pain at some point in their lifetime. It is the most common cause of chronic pain, and is a major contributor of missed work and disability. For most individuals, back pain is self-limited. In most cases of herniated disks and stenosis, rest, injections or surgery have similar general pain resolution outcomes on average after one year. In the United States, acute low back pain is the fifth most common reason for physician visits and causes 40% of missed days off work. Additionally, it is the single leading cause of disability worldwide.
Spinal disk disease occurs when the nucleus pulposus, a gel-like material in the inner core of the vertebral disc, ruptures. Rupturing of the nucleus pulposus can lead to compression of nerve roots. Symptoms may be unilateral or bilateral, and correlate to the region of the spine affected. The most common region for spinal disk disease is at L4-L5 or L5-S1. The risk for lumbar disc disease is increased in overweight individuals due to the increased compressive force on the nucleus pulposus.