WHEN TO SEE A SPINE SPECIALIST

You should seek the advice of a spine specialist if neck or back pain persists for more than two weeks or if it is progressive in intensity and/or distribution. You should seek immediate healthcare attention if neck or back pain occurs as the result of an injury or if it is associated with serious illness and/or a high fever. Additional signs and symptoms which warrant prompt medical attention include:

• Neck or back pain associated with bowel and/or bladder dysfunction
• Neck or back pain associated with extremity weakness or difficulty with coordination
• Extremity numbness or muscle weakness
• Neck or back pain that is associated with impaired walking (gait) or difficulty with balance
• Numbness, tingling and/or muscle weakness associated with a back or neck injury

SCREENING AND DIAGNOSIS

X-ray studies often reveal a loss of vertical disc height, osteophyte formation and bony endplate irregularity. X-ray may also reveal a vacuum phenomena characterized by a gas signal within the degenerative disc. Computerized tomography is helpful for the evaluation of associated disc bulge or herniation. It also provided a detailed view of bony changes such as osteophytes (bone spurs) adjacent to the degenerative disc.

CT helps to evaluate the spinal joints (facets) at the level of DDD and is an excellent tool to rule out spinal stenosis. MRI is the single most valuable imaging tool for confirming the presence and degree of DDD. One of the best indicators on MRI is a loss of T2WI signal within the disc consistent with a loss of water content. MRI can also be used to evaluate the relationship between the inner nucleus of the disc and the supportive (annular) fibers which surround the disc. With DDD there will be a loss of demarcation between the dissimilar tissues. MRI is also used to evaluate for spinal joint arthritis, disc bulging, disc herniation and spinal stenosis at the level of DDD.

There are numerous spine conditions which may present with symptoms similar to a degenerative disc these conditions include:

• Traumatic Disc Herniation
• Disc Hypoplasia (Underdevelopment)
• Disc Space Infection (Discitis)
• Seronegative Spondyloarthropathy
• Hemodialysis Spondyloarthropathy

CAUSES

The causes of degenerative disc disease are multifactorial. For some there is a likely a genetic predisposition. It is more common in individuals who sit for prolonged periods of time and who work at heavy manual labor jobs. Cigarette smoking and obesity has been linked to DDD and increased risk for back pain. DDD is characterized by disc desiccation (dehydration) and increased collagen content. There is a reduction of cells within the annulus with a shift to a greater quantity of type II collagen. The diminished number of cells within the disc is associated with reduced the healing capacity of the disc. There is a loss of hydrostatic properties leading to a loss of disc flexibility and shock absorption capability.

DDD disease is often preceded by endplate abnormalities which further lead to a loss of diffusion and nutrient delivery to the disc. The endplates show progressive thinning. Bone marrow changes may take place subadjacent to the endplate. The loss of disc volume leads to reduced spacing between adjacent vertebrae and increased mechanical stress upon the spinal joints (facets). This increases the risk for facet arthropathy/arthritis and associated pain.

NATURAL HISTORY AND PROGNOSIS

Low back associated with DDD is often self limiting. Less than 10% of individuals with neck or back pain associated with DDD will develop chronic pain. A smaller percentage of individuals develop disabling symptoms. There are varying stages of degenerative disc disease. Most stages are associated with some degree of segmental dysfunction at the level of the DDD. The later stages are often associated with degenerative bony changes involving the development of bone spurs. A degenerative disc is more likely to herniate than an normal disc when injured.