Minimally Invasive Spine Surgery - Artificial Disc ReplacementThe disc is the soft cushioning structure located between vertebra of your spine. The disc is made consists of an outer section called the annulus fibrosus and the inner nucleus. An artificial disc is surgically placed into the spine to allow for the functions of a natural spinal disc.
There are many disc designs that either replacement the entire disc or just the disc nucleus replacement. Artificial discs can be made of metal and/or biopolymer materials. These consist of surgical grade materials have been used in the body for decades. Total disc replacement is not a new technology, they have been used carried out since the early 1980’s. The most common total disc replacement designs have two plates with one attaching to the vertebrae above the disc being replaced and the other to the vertebrae below the replacement site. Some replacement discs have a soft plastic-like piece between these plates. The devices allows for motion by having it’s smooth surfaces slide across each other.
Nucleus Replacement Devices
Several nucleus replacement devices are made of a biopolymer material called hydrogel which expands as it absorbs water. The artificial nucleus is placed into the nuclear cavity of the disc and hydrates to expand and fill the cavity. The device can be compressed by the spines natural movements and can function like a healthy, natural disc nucleus. Another design for nucleus replacements is made up of a plastic-like material that is wound up to fill the nuclear cavity.
No nuclear replacement devices are not currently available for use in the United States. FDA-approved studies have not started or been allowed. There are also cervical neck disc replacements that have only been used a relatively short time, while several other designs are currently undergoing evaluation in FDA-approved trials.
Proper Diagnosis To Determine Origin Of Pain
The symptoms that indicate that a disc replacement may be required can vary for each type of implant. Symptoms may include pain originating from the disc that has not been resolved sufficiently with non-surgical care including pain medications, spinal injections, chiropractic care or physical therapy. A physician or surgeon will obtain imaging studies to corroborate the results of certain tests with findings from the patient’s history and physical examination to accurately determine the source of pain.
Are You A Candidate For Artificial Disc Replacement?
There are several conditions that may prevent you from receiving a disc replacement including spondylolisthesis (where one vertebrae slips across a lower one), osteoporosis, vertebral body fractures, allergic reactions to the metals or polymers in the artificial discs, tumors, infection, obesity, degeneration of the facet joints, pregnancy, prolonged steroid use or autoimmune deficiency disorders.
Total disc replacements are surgically implanted through the abdomen. If you have previously had abdominal surgery or if the blood vessels in front of your spine are compromised there may be an increased risk of significant injury during this type of spinal surgery and you may not be an eligible candidate for artificial disc replacement.
Selection of Artificial Disc Replacements
The type of artificial disc to use depends on the source of pain and the degree and progression of the underlying disorder. A nucleus replacement may be an option for patients with early disc degeneration and if the annulus is relatively undamaged. A nucleus replacement may also be implanted after a discectomy where removal of a large amount of disc tissue has been preformed. In discs with severe degeneration, a total disc replacement may be indicated.
Risks & Complications
As with any surgery, there are risks associated with disc replacement and complications are similar to anterior spinal fusion complications. Possible complications include but are not limited to: infection, injury to blood vessels, nerve injury, dislodgment of the disc, destruction of the disc, breakdown of the disc materials, non-resolved or increased pain, development of new pain, sexual dysfunction, injury to urologic structures and possibly death. These risks should be discussed with your surgeon before deciding to proceed with artificial disc replacement surgery.