The intervertebral fusion cage is a tool for your doctor to use in helping treat various low back problems. For patients who require spinal fusion surgery to treat degenerative disc disease, the intervertebral fusion cage has been shown to be effective for several reasons:
- Low complication rate
- Minimized pain after surgery due to less trauma during surgery
- Shorter hospital stay compared to other types of fusion methods
- Quicker return to daily activities
The intervertebral cage is not designed to treat all types of spinal problems. You may be a candidate if your pain is from degenerative disc disease with segmental instability.
The intervertebral fusion cage is a large spacer made of metal, plastic, or bone, that is implanted between 2 vertebraehollow cylinder. The cages are made from various materials including metal or carbon graphite fiber. Your doctor will place bone graft inside the cylinder. The holes in the cage keep the graft in contact with the bony surface of your vertebrae. This ensures that the bone graft unites with the vertebrae, forming a solid fusion.
The intervertebral cage helps in several ways. The solid cage separates and holds two vertebrae apart. This makes the opening around the nerve roots wider, relieving pressure on your nerves. As the vertebrae separate, your ligaments tighten up, reducing instability and mechanical pain. The cage also replaces the problem disc while holding your two vertebrae in position until fusion occurs.
The intervertebral cage was first approved for use by the United States Food and Drug Administration (FDA) in 1996. It has been proven to be a safe procedure, and several devices have since been approved for use by the FDA.
Intervertebral cages can be implanted from the front, side, or back of your spine. They can also be implanted using an approach that is slightly from your side and slightly from your back, which is called a transforaminal approach, and they may also be implanted using a minimally invasive surgery (MIS) technique.
Surgery to implant an intervertebral cage from the front of your body is called an anterior interbody fusion. In this procedure, your doctor will move your organs and blood vessels to the side to access your spine, but he or she does not have to move your nerves out of the way to implant the intervertebral cage.
When surgery to implant an intervertebral cage is performed through the side of your body, it is called a lateral interbody fusion. Other names for this procedure are direct lateral interbody fusion (DLIF) and extreme lateral interbody fusion (ELIF). The lateral approach uses a smaller incision compared to anterior and posterior approaches while still allowing your doctor to directly see your spine as the surgery is being performed. Lateral interbody fusion can also be performed using a minimally invasive surgery (MIS) technique. Using an MIS technique, your doctor will make 2 small incisions in your side instead of one large incision, which potentially enables the surgery to be performed in less time, and with less trauma and pain than traditional surgical approaches.
The procedure to implant an intervertebral cage from back of your body is called posterior interbody fusion. To access your spine using this approach, your doctor will need to remove the lamina of the upper vertebrae and move your nerve roots out of the way. Posterior interbody fusion can also be performed using an MIS technique, making 2 small incisions in your back instead of one large incision to minimize the time, trauma, and pain associated with more invasive surgical techniques.
Intervertebral cages implanted slightly from your side and slightly from your back use a transforaminal interbody fusion approach. Using this approach, your doctor can implant the intervertebral cage with little or no disruption of your nerve roots or back muscles.
In most cases, two cages are placed side by side to replace one disc. Your doctor will drill two holes through the front of the disc. Before putting one cage into each hole, your doctor will prepare the cages. Bone graft may be taken from your pelvis bone through a small incision on your side, but this second incision may not be needed if your doctor uses a bone graft substitute.
Your doctor will pack the intervertebral cages with the bone graft and insert the cages side by side into the drill holes. A fluoroscope is used to make sure the cages are in the correct position.