Axial lumbar interbody fusion, also called Axial LIF or AxiaLIF, is a minimally-invasive surgical technique used to fuse together the last bone in the lumbar spine (lower back) and the first bone in sacrum, which sits at the rear of the pelvis. Access to this portion of the spine through other fusion techniques—including posterior lumbar interbody fusion (PLIF) and transforaminal lumbar interbody fusion (TLIF)—is relatively difficult, and AxialLIF gives surgeons a way to achieve fusion in this area with comparatively few problems.
Interbody Fusion Basics
All forms of interbody fusion involve the removal of the cushioning disc that normally sits between adjacent spinal bones (vertebrae), followed by the insertion of a device called a bone graft into the resulting gap in the spinal column. Over time, this graft promotes the formation of new bone tissue that takes the place of the missing disc and joins, or fuses, the neighboring vertebrae together. Most interbody fusion procedures are performed by accessing the spine from the front, rear or side of the body. While some of these surgeries rely on traditional open surgery techniques, others are classified as minimally-invasive and intentionally reduce the tissue and structural damage associated with open surgery.
Even in minimally-invasive procedures, interbody fusion normally requires the operating surgeon to cut through ligaments, muscles and other local tissues in order to create an incision that’s large enough to place the bone graft and its supporting structure in between the targeted vertebrae. More traditional procedures come with significant risks for damage of local nerves and blood vessels, and require relatively lengthy hospital stays for postsurgical recovery.
In axial lumbar interbody fusion, the connection between the last lumbar vertebra (known as L5) and first sacral vertebra (known as S1) is accessed through a very small incision in the skin next to your tailbone, or coccyx, which sits directly below the sacrum. After making this incision, your surgeon will create a narrow channel to main site of the procedure. He will then use this channel to achieve the objectives of the surgery, including removing damaged portions of the targeted spinal disc and placing bone graft material in the space between the L5 and S1 vertebrae. In addition, your surgeon will use the this channel to insert a metal support rod that runs through the site of the graft to anchoring points in the adjoining bone.
Benefits of the Procedure
Unlike other forms of interbody fusion, AxiaLIF does not result in complete removal of the spinal disc between the targeted vertebrae. Instead, your surgeon will leave the main outer structure of the disc, called the annulus fibrosus, more or less intact and only remove the damaged sections of disc material that are triggering your symptoms. Because of the angle used to approach the site of the procedure, damage to your tissues is greatly reduced; as a result, you will typically require a much shorter recovery period than people who undergo most other forms of interbody fusion. You may be an especially good candidate for axial lumbar interbody fusion if you have anatomical features that make access to this part of your spine through other means difficult, or if you have other problems that make other surgical approaches inappropriate or dangerous.
While axial lumbar interbody fusion has produced few problems according to a number of limited studies, the procedure is still too new for doctors and researchers to fully understand all of its potential long-term risks and complications. You are typically not a good candidate for surgery that includes only AxiaLIF if you have a compressed spinal nerve or scar tissue in the vicinity of your coccyx and/or sacrum. Doctors sometimes combine AxiaLIF with other traditional or minimally-invasive back procedures, which come with their own specific risks and potential complications.