Radiculopathy is characterized by motor and/or sensory changes in the neck and arms or the legs and feet, which results from extrinsic pressure on the nerve root. This pressure is typically caused by disc material, swelling, or osteophytes. A large study in Rochester, Minnesota, has reported the annual incidence of cervical radicular symptoms to be 83.2 per 100,000 population, and its prevalence most significant within a 50- to 54-year age group. In the study, 90 percent of patients were asymptomatic or only mildly incapacitated. Surgery is not often required for resolution of cervical radiculopathy symptoms.
Radicular pain, the characteristic symptom of cervical radiculopathy, is often confused with radiating pain in clinical practice. Because specific treatments are exclusively indicated for radicular pain, an accurate distinction is important. True radicular pain follows dermatomal patterns and is usually — though not always — unilateral. Onset is often insidious but may also be abrupt, and the pain is frequently aggravated by arm position and extension or lateral rotation of the head.
There are three primary types of pain:
Local Pain is caused by irritation to the structures in the back including bone, muscles, ligaments and joints. The pain is usually steady, sharp or dull, felt in the effected area of the spine and may change with changes in position or activity.
Referred Pain can be pain caused by non-spinal pathology that is referred to the back, such as an abdominal aortic aneurysm. Referred pain can also be pain originating in the spine that is felt in distant structures. For instance upper lumbar pain is frequently felt in the upper thighs, and lower lumbar pain is felt in the lower buttocks. Sacroiliac joint pain is often referred to the inguinal and antero-lateral thigh area. Referred pain rarely extends below the knees, where as nerve root pain can be felt in the calf or foot.
Radicular Pain is caused by irritation of the nerve roots (radix) and is usually more severe than referred pain, and may have a more distal radiation. Radicular pain usually circumscribes the territory of innervation of the given nerve root (in a dermatomal distribution). This type of pain is often deep and steady, and can usually be reproduced with certain activities and positions, such as sitting or walking. In addition, radicular pain is frequently exacerbated by any maneuver that raises the pressure of cerebrospinal fluid (or the interabdominal pressure), such as valsalva, sneezing, or cough.
Radicular Pain Distribution
Radicular pain radiates into the extremity (thigh, calf, and occasionally the foot or to the arm, forearm or hand) directly along the course of a specific spinal nerve root. The most common symptom of radicular pain is sciatica (pain that radiates along the sciatic nerve – down the back of the thigh and calf into the foot) and arm pain and paresthesia of the hand. Sciatica is one of the most common forms of pain caused by compression of a spinal nerve in the low back. It may result from compression of the lower spinal nerve roots (L5 and S1). With this condition, the leg pain is typically much worse than the low back pain, and the specific areas of the leg and/or foot that are affected depends on which nerve in the low back is affected. Compression of higher lumbar nerve roots such as L2, L3 and L4 can cause radicular pain into the front of the thigh and the shin.