What is Lumbar Interbody Fusion?
Lumbar interbody fusion is a surgical procedure that involves fusion of the vertebrae that form the lumbar part of the spine. It is indicated when there is significant damage to the intervertebral discs, which are the soft cartilaginous discs that lie in between the vertebral bones. It may also be performed when there is age-related damage or herniation of the intervertebral discs. Lumbar interbody fusion is a type of spinal fusion surgery.
How is the Procedure Performed?
There are two different approaches to lumbar interbody fusion. One approach is through the front of the spine while the other one is through the back. In this article, we shall discuss the anterior approach i.e. lumbar interbody fusion performed from the front of the spine.
The procedure is performed under general anesthesia. Consent is obtained from the patient and the area where the surgery is due to be performed is cleaned with antiseptic solution. The patient is covered in sterile drapes and an incision is made in the abdomen. After the moving any intervening structures out of the way, access is obtained to the front of the spine.
The damaged disc is clearly visualized through this approach and is gently removed using surgical instruments. Removal of the disc creates an empty space in between the vertebral bodies. In order to fill this space, temporary spacers are inserted. These temporary spacers help realign the vertebra by putting the vertebral bones back in their normal position. Doing so helps relieve any pressure that is being placed on the nerves by the collapsed vertebrae.
The temporary spacers are replaced with a strong threaded metallic cage which is filled with bone graft. The cage is screwed in place using metallic screws. The temporary spacer is removed and another cage is placed in its spot.
The bone graft that has been inserted into the cage eventually fuses the two vertebrae. In other words, spinal fusion occurs through the medium of a bone graft bridge.
Advantages of Anterior Lumbar Interbody Fusion
The main advantage of performing lumbar interbody fusion through an anterior approach is that the chances of damaging any nerve fibers that emerge from the spinal-cord is minimal. Furthermore, patients tend to recover a lot better through this procedure. The bone graft that is placed in between the vertebrae is compressed more effectively and hence fusion of the spinal bones is better. Finally, a larger implant can be placed in between the vertebral bodies when adopting an anterior lumbar approach.
The risks are very few and can include damage to the nearby blood vessels and blood loss. In the rare cases, a condition known as a retrograde ejaculation can occur in men. This is because there may be mild damage to the L5 and S1 vertebrae which control ejaculation during sex. In retrograde ejaculation, the semen which is normally expelled out goes back into the bladder as it is the path of least resistance. This phenomenon may recover over time.