Spine Fusion Procedures
What Is It?
Spine fusion procedures are operations that aim to "fuse" two or more adjacent vertebral levels into one unit which moves together. Normally, the spine has the capability of many degrees of motion as each vertebra (a bone of the spine) moves independently. These normal movements are limited by the soft tissues that connect the bones including the intervertebral discs, facet joints, ligaments and muscles. If two or more levels are fused in a spinal fusion procedure then those levels act as one solid unit.
Spine fusion is performed in many different ways, depending on the specific spine pathology and anatomy which is present. In general, a spinal fusion aims to get the involved bones to fuse together by growing bone across them. The procedure itself does not do this, it simply encourages the body's natural healing process to scar and form new bone to result in fusion.
Some of the procedures used to encourage spine fusion include:
- Discectomy - As the intervertebral disc is one of the large soft tissue structures separating any two vertebrae, it often must be removed in order to encourage fusion across the two or more levels. A discectomy is the removal of the disc so that raw bone edges of the two vertebrae are exposed and can form new bone across the gap, often augmented by bone and/or a support of some type which is placed in the disc space.
- Instrumentation - Spinal instrumentation refers to placing hardware which helps to stabilize the spine while it heals and to promote fusion. This can include wiring and bone screws which, along with rods or plates that connect them, hold the bones relatively stable. It can also include cages made of metal or other materials which are placed in the space between adjacent vertebrae to help support them and encourage bone growth across them.
- Implantation of bone - Using bone in the fusion construct helps to encourage further bone growth and spine fusion. This can be pieces or dust of the patient's own bone or can also include banked bone from a cadaver.
- Bone Morphogenic Protein (BMP) - Occasionally, a special synthetic protein which is normally found in the body can be used to encourage bone growth and thus fusion.
Following surgery, recovery can require external immobilization with a brace or neck collar to keep the area immobile while it heals and the fusion is formed. It can take weeks or months for the scar and bony tissue to fuse across the levels so that the fusion is complete and stable. If the patient does not fuse completely, they can continue to have instability at that level after the procedure and may require further operations. The specific treatments and prognosis for these pathologies and procedures are different from patient to patient. Consult your own treating physician about options and prognosis.
What Is It Used For?
Spinal fusion is used to treat or prevent spinal instability
. Normally, the movement of the spine is controlled by its ligamentous, disc and muscle attachments. In some pathological states, this movement can become abnormal, leading to increased mobility of a part of the spine, termed spinal instability. This instability can be symptomatic, causing pain and/or neurological symptoms due to compression of the spinal cord or spinal nerves. This instability can occur secondary to trauma, degenerative spine disease or prior surgical operations of the spine. Along with instability, these patients often have an abnormal configuration of the spine so that the normal alignment of the spine is compromised.
When a patient presents with instability or is undergoing surgery to the spine which may produce instability they may be recommended to undergo a spine fusion procedure. The goal is to prevent further instability, reverse symptoms, avoid future injury to the spine and improve alignment by fusing the spine in a more appropriate alignment.
The levels and size of a spinal fusion depends entirely on the specifics of each case. In many cases, only two levels are fused together. However, for more severe spine disease or complex problems such as severe scoliosis, many levels may be fused. The more levels that are fused, the less mobility the patient will have after the procedure in that part of the spine.
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This site is not intended to offer medical advice. Every patient is different, and only your personal physician can help to counsel you about what is best for your situation. What we offer is general reference information about various disorders and treatments for your education.