Anterior Lumbar Interbody Fusion
Spinal fusion surgery is an effective treatment that brings substantial relief from severe, continuous low back pain caused by degenerative disc disease.
Fusion is the process of stabilizing the spinal vertebra and the disc by joining bones through grafting. Bone tissue begins to grow between the two vertebral elements, stabilizing the segment and providing pain relief.
While fusion can be accomplished in a variety of ways, the Anterior Lumbar Interbody Fusion (ALIF) procedure allows the spine surgeon to approach the spine avoiding entry through the lower back, thereby not cutting through muscle tissue. The advantage of the ALIF approach to spine surgery is that the back muscles and nerves remain intact.
Conditions Treated by ALIF
The ALIF Procedure
In this procedure, the surgeon works on the spine from the front of the spine (anterior) in order to remove a spinal disc located between two adjacent vertebrae in the lower (lumbar) spine.
ALIF surgery usually begins with a three-to-five-inch long incision on the one side of the abdomen. Abdominal muscles and blood vessels are then pulled to the side to provide the surgeon access to the spine without cutting through the muscles of the abdomen.
A type of implant, called a cage, is then inserted into the disc space. The cage helps restore the normal spacing between the vertebrae, easing pressure on the nerve roots.
During the surgery, the patient’s own bone graft material is usually taken from the front of the patient’s iliac crest, or hipbone, for the procedure (there are also a variety of bone graft substitutes that are available for use in spine fusion surgery, if necessary). The bone graft material is then placed in the cage and, in some instances, in front of the cage. At times, additional support is required, at which point screws are then inserted through the cage.
In the months after the surgery, the bone graft fuses through and alongside the cage, creating a long bone between the vertebrae and immobilizing that segment of the spine, relieving pain.
Getting To The Back From The Front
The majority of spine surgery performed in this country and worldwide for the treatment of spinal conditions such as disc herniation, disc desiccation, sciatica surgery, etc, are performed via an incision made in the back of the spine. This is with good reason: the spinal discs often protrude backwards towards nerves and are best engaged from a posterior or back cutting procedure. However, since the 1950s, anterior lumbar interbody fusion has been employed. This approach actually attempts to get to the spinal discs from an incision in the anterior abdomen. Occasionally, this can be done through very small vertical or horizontal incisions. There are even practitioners doing this from a laparoscopic approach, although this has come out of favor in recent years because of its increased risk.
Anterior lumbar interbody fusion (ALIF) surgery offers some major advantages over a posterior approach. The muscles of the back, which are quite large, do not need to be stripped in order to capture and remove the disc. Furthermore, when a significant desiccation or collapse of the disc exists, the remnant desiccated disc can be removed from the front and a very large bone graft or synthetic device, known as a cage, can be placed within the disc space to allow for a significant increase in height. Most practitioners believe that this approach will allow for a more accurate and larger restoration of disc height than an approach from the back. Surgery from an anterior aspect allows for a salvage procedure when surgery from the posterior approach has already failed. With the advent of more modern instrumentation, now screws, rods and plates can be done with good stability from an anterior spinal surgery.
Not everyone is a candidate for ALIF. One of the major concerns is a one percent chance of retrograded ejaculation in males after an approach into the anterior abdomen, as well as the concern of bowel and vascular issues from an anterior approach