What is Spinal Instability?
Spinal instability occurs when the vertebrae do not respond appropriately when faced with physiological loads. Instead of managing the load properly, the spine moves in patterned ways that cause pinching or irritation of nerve roots. It can also lead to excessive pressure on the facet joints, which are located between adjacent vertebrae and serve to stabilize, causing inflammation. In an attempt to stabilize the area, the paraspinal muscles will frequently spasm, which can sometimes lead to the back locking up. Continuous instability results in faster degeneration of the area of the spine and can also be a source of pain for those experiencing it.
What Causes Spine Instability?
There are a series of events that occur in the process that leads to spinal instability. Vertebral discs, when functioning properly, serve as shock absorbers and manage the degree of flexibility and motion of each segment of the spine. When discs are herniated or degenerated, they lose tension, which makes them bulge and increases movement between vertebrae. In addition, when discs degenerate they lose height, which causes the facet joints to become displaced and move out of their proper alignment. This can lead to arthritic overgrowth of the joints and the production of bone spurs, which are bony projections along joints that limit movement and cause pain. You experience pain when you extend or flex and the vertebrae move abnormally. This movement irritates the nerve and causes back or leg pain. Some conditions that contribute to spinal instability include:
- Degenerative Disc Disease
- Weak spine caused by infection or tumor
How is Lumbar Instability Treated?
The goal of spinal fusion surgery is to eliminate or reduce pain caused by joints that have worn out over time. In the surgery, two bones that are separated by a joint are joined together to grow into one bone. To do this, surgeons use a bone graft, which can be taken from the patient’s pelvis or a bone bank. There are many different approaches to this kind of surgery, in terms of the location where the surgeon will perform the surgery, and your doctor will determine which option is best for you based on your specific set of symptoms. All of the options are designed to prevent motion at the vertebral segment. Some of the options include:
- Anterior approach: This approach allows the surgeon to remove the intervertebral disc from the front and place a bone graft between the vertebrae. The incision is made in the abdomen above the pelvic bone. Organs in the abdomen are moved to the side to enable the surgeon to see the front of the spine. Once the problem disc is located it is removed and bone graft is placed in its previous location.
- Posterior approach: The incision is made in the back of the patient. In this surgery the vertebrae can either be fused or the disc is removed. If it is removed, it is replaced with bone graft. The incision is made in the middle of the lower back, at the location of the spine where it will be fused. From this approach, the surgeon can see areas of pressure and what is causing them, whether it is a bone spur, bulging disc, or thickened ligaments. After removing whatever is causing the pressure, the fusion is performed with a bone graft.
- Combined approach: Because of the limitations of just performing surgery from the front or back, and not getting the full scope of what the patient needs to improve their symptoms, surgeons will sometimes make an incision from the front and from the back. This can either be performed at the same time or in two separate operations.
If the surgery is successful, the vertebrae will need three months to fully fuse together, and will continue to fuse and grow for the next one to two years. You may be required to wear a brace to ensure complete stability and spinal fusion, depending on the location of your surgery and instruments used. Your doctor will put a post-surgical rehabilitation program in place to your improve mobility and strength and have you returning to your old activities as soon as possible. Physical therapy is frequently a part of this rehab program, which promotes the flexibility and strength of your spine.
If you are experiencing back pain, your spine might not be stable. After visiting your doctor and getting your symptoms assessed, the next step is deciding what treatment path you want to take. The team at The Center for Musculoskeletal Disorders is experienced in treating spinal instability using conservative methods, and when needed, performing spinal fusion surgery. If you have questions about what options are available for you to manage pain, make an appointment for a consultation with one of our doctors.