Total Artificial Disc Replacement is the latest innovative technology and is an alternative surgical treatment for patients with chronic back pain caused by Degenerative Disc Disease (DDD) which can give them a chance to return to a permanent symptom-free life.

Degenerative Disc Disease results in a flattened disc space so losing its normal height. This height is important as it separates the disc above from the one below. When disc height is lost, the nerve root pathways may become narrow and result in nerve impingement, inflammation, and pain. It can occur at any spinal level although it is very common in the lumbar region. Severity of back pain does not depend only on the pathology caused by the disc shape; the patient's age or traumatic disc condition and various other factors are also involved.

Early research in the development of artificial disc replacement began in Germany in 1984. It followed more than a decade of research on the spinal degenerative processes, spinal biomechanics and biomaterials before serious efforts to produce an artificial disc commenced. The first patients to have a TADR are still pain free and leading normal social and working lives 20 years after their operations.

Total Artificial Disc Prosthesis preserves normal movement between two vertebral bodies preventing them from collapsing and irritating or damaging the nerve roots - by maintaining the disc space height between both bony surfaces. It leads to resto- ration of spinal stability similar to the beneficial effect of total knee or hip replacement..

Patients who suffer with chronic low back pain caused by DDD, will return to a normal pain free life. Also total disc replacement protects the discs at the adjacent levels by distributing the stress through the lower back during normal activities such as lifting and bending (flexion and extension).

Total Artificial Disc Replacement is, in fact, different from the procedure called artificial disc replacement which requires the removal of disc tissue and the placing of a device such as a Titanium or a Carbon fiber cage to refill the disc space and act as a spacer and restore disc height. This type of procedure will prevent movement between the affected discs by fusing both vertebrae together.

Treatments of chronic low back pain are divided between conservative therapies and surgical treatment. When conservative therapies have failed, surgery is often the next step. This usually means spinal fusion surgery. In fact the overall process is successful for back pain treatment. But a spinal fusion at one or more levels causes stiffness and decreased motion of the spine, increasing stress on the rest of the spine. This transferred stress may cause new problems at other levels, leading to the need for further back surgery or else a decrease in the quality of life.

Total Artificial Disc Prosthesis is composed of two metallic endplates and a polyethylene core that moves between them. The endplates are made of cobalt chromium alloy with bioactive-coated surface of titanium and calcium phosphate (TiCaP).
A pair of endplates is inserted in the space between two vertebrae and bioactive-coated surface attached to the vertebrae above and below. The nucleus which is made of Ultra High Molecular Weight Poly Ethylene (UHMWPE) is then inserted between the two endplates to create a disc-like structure which mimics the normal human nucleus pulposus by providing both a normal space between the two vertebrae and allowing the usual range of motion and flexibility for that segment of the spine.

The advantages of the Total Artificial Disc Replacement

1. Restoration of spinal stability
2. Restoration of nearly-normal physiologic mobility of spine
3. Restoration of normal disc space height

Spinal Fusion (usual standard method in spinal surgery)

Conservative treatment of Degenerative Disc Disease (DDD) is usually effective in patients with early stage back pain within a short-term remittance. But in some individuals who suffer from chronic low back pain, such as degenerated disc disease, as the underlying cause remains and interferes with patients occupation and normal daily activities, this may lead to the requirement for surgical intervention.

Lumbar spinal fusion or arthrodesis, the standard surgical treatment in DDD, necessitates the removal of the disc tissue and fusing both vertebrae together with a bone graft and sometimes supplemented with pedicle screw fixation. Patients usually are free of back pain after fusion but lose their ability to move in the "fused" segment and the post operative recovery period varies from 3-4 months. Failure of the fusion may be associated with a return of the symptoms.

Spinal fusion in one or more levels will create some stiffness and reduced movement of the spine causes more stress at its adjacent levels. These problems with the transferred stress in the adjacent levels may increase the risk of further degeneration of the adjacent discs which may lead to additional back surgery.

Post-operative care for Total Artificial Disc Replacement (TADR)

After the TADR procedure, the damaged disc is replaced with a mobile prosthesis. With the movement preservation that this affords, the stress at the adjacent segments is not increased. Rather than wearing a rigid brace, which is often necessary following a fusion procedure, patients are encouraged to move their trunk after TADR surgery.
Since TADR is an anterior-approach with a smaller incision, there is less blood loss and significantly less pain. Early ambulation leads to earlier rehabilitation and recovery as compared with the standard posterior spinal fusion.

Comparison of Total Artificial Disc Replacement and Standard Spinal Fusion

Indications and contra-indications of TADR
Patients suitable for TADR
Best candidates are :

1. Age 18-60 years old
2. Patients with discogenic back pain who have been suffering from 1 to 3 levels of DDD with or without previous back surgery
3. Long-term chronic back pain over 6 months
4. Disc herniation with back pain predominated
5. Recurrent Disc Herniation

Patients not suitable for TADR
Any patients who have following conditions

1. Osteoporosis
2. Spondylolisthesis
3. Back pain not arising from Degenerative Disc Disease
4. Infection or tumor of spine
5. Morbid obesity or BMI (Body Mass Index) > 40%
6. Spine deformities from trauma
7. Facet arthrosis
8. Obvious scoliosis or kyphosis

Duration of Artificial Disc Prosthesis

          The estimated life-span of an artificial disc prosthesis is over 80 years, this compares favourably with the 10-15 years life of a hip or knee replacement. Already twenty years after the first artificial disc implantations the first patients are still living pain and symptom-free lives.