I saw a short videotape at the surgeon's office about spinal fusion using a tiny incision from the side of the person. The idea is to avoid cutting into the back muscles to get to the bones of the spine. Can you tell me how this method compares to the regular way of doing the surgery?
There are many different ways to treat low back pain. When surgery is needed, there are different options as well. Spinal fusion may be necessary in the case of degenerative disc disease, tumor, infection, deformity, or spinal instability. Just like everything else, fusions can be done in different ways with different approaches.
Interbody fusion is a common method of performing spinal fusion. Interbody refers to the fact that after removing the disc, the surgeon inserts a metal cage, spacer, or bone graft material in the empty space between the two vertebrae. Bone graft material is packed in and around the area to help the fusion process along.
Even with interbody fusion, there are different ways to approach the spine. The surgeon may come in from the front of the body. This is called the anterior approach. Surgery from the back of the spine is a posterior approach. Sometimes a posterolateral approach is used -- angled between the back and the side. No matter which method is used, the goal is always the same: to restore the disc height and vertebral segment spacing and restore spine stability as close to normal as possible.
Each approach has its advantages and disadvantages. There is even a new way of doing this surgery called extreme lateral interbody fusion (XLIF). It sounds like this might have been the type of surgery you viewed in the office. The surgeon goes through the side with only disruption of the psoas (hip) muscle. There are no major organs to avoid (as with the anterior approach). There's no need to strip away large groups of muscles or cut through nerves (as with the posterior or posterolateral approach).
Special X-ray techniques such as fluoroscopy and real-time electromyography (EMG) are used to guide the surgeon and monitor the patient. Using these tools, the surgeon can move safely through the body to the spine avoiding the abdominal contents and without damaging vital nerves, blood vessels, and soft tissues.
The most difficult part of the operation is to move through the psoas muscle without disrupting the lumbar nerve plexus. That's where EMG comes in handy. The tool used for the XLIF has a tiny EMG electrode on the tip giving the surgeon continuous feedback on the location of the psoas muscle. The fluoroscope is used once again after the disc material has been removed to put the spacer in place and to pack it with bone graft material.
XLIF was developed in response to some of the problems that occur with other types of fusion procedures. The XLIF is less invasive with a smaller incision, less disruption and damage to the soft tissues, decreased blood loss, and provides a faster recovery.
With the ability to gain access to the disc space without stripping away the muscles, there is a hope that future problems with adjacent segment degeneration can be prevented. Adjacent segment degeneration refers to the breakdown of the next vertebral segment as a result of a transfer of load from the fused site to the next mobile segment.
Studies done so far with the XLIF report good results. There's been no question about the safety and effectiveness of XLIF for interbody fusion. They have even used it with multilevel fusions in patients with other problems like scoliosis. But the studies are limited and with only a few patients. Larger, randomized controlled trials comparing XLIF to other fusion operations are still needed before this approach will be widely adopted.