Anterior lumbar interbody fusion is a surgical procedure done through the abdomen to remove a diseased intervertebral disc and replace it with a spacer, thus restoring the disc height, decompressing the nerves, correcting deformity and fusing the vertebrae together in the corrected position.
Three main indications for ALIF:
- Degenerative disc disease causing disc collapse with compression of the nerves and back pain
- Spondylolisthesis, which is instability between the spine bones, when two vertebrae shift next to each other
- Recurrent disc herniation
What are the goals of ALIF?
There are three main goals:
- Restore height of the disc space and remove pressure from the surrounding nerves
- Correct alignment of the bones
- Remove abnormal movement by fusing the bones together
How is the procedure performed?
ALIF is performed through the abdomen. Skin is incised, muscles are retracted and content of the abdomen is pushed away from the spine. Large blood vessels in front of the spine are protected and the surface of the diseased disc is visualized.
The disc is then removed using sharp instruments and the space between the bones is filled with a spacer secured in place with screws. Bone graft is placed inside the spacer to promote bone fusion. In some cases, supplemental screws are inserted from the back through small incisions using a portable X-ray machine.
What is recovery like after the surgery?
Since there is no large incision over the spine and no significant damage to the spinal muscles, patients tolerate this procedure much easier compared to the traditional open spine surgery.
There is less pain compared to the traditional posterior spine surgery and most patients are able to leave the hospital after a one-night stay.
Are there any limitations in physical activity after ALIF?
Yes, to achieve fusion you would have to maintain certain limitations in physical activity for at least three months (average time required for fusion).
An easy way to remember recommended activity modifications is to “avoid BLTs”:
- No Bending
- No Lifting heavier than five pounds
- No Twisting (such as golfing or sweeping the floor)
How much mobility would I lose as the result of fusion?
One spinal disc has range of motion of no more than 5-10 degrees. In fact, when you bend forward, most range of motion occurs across the hip joints, not spine. As such, fusing one disc space does not lead to noticeable loss in the range of motion.
What are the risks of ALIF?
Together with the usual surgical risks like infection and blood loss, there are specific risks of ALIF related to the anterior approach through the abdomen:
- Slowing of the bowel function causing nausea, vomiting and inability to tolerate regular food – this may last for a day or two after surgery
- Injury to the internal organs: bowel and large blood vessels lying in front of the spine
- Retrograde ejaculation – this is important in young males planning to have family since it may lead to infertility (chance of 2%-4%)
What are limitations of and alternatives to ALIF?
In cases when the spine cannot safely be approached through the abdomen, traditional open spine surgery may be used. These cases include obesity, previous extensive abdominal surgeries, unfavorable anatomy of the blood vessels and pelvis and unacceptable risk of retrograde ejaculation.
At the spine levels above L4-5, anterior approach to the spine may also be complicated. In those cases, an LLIF, Lateral Lumbar Interbody Fusion, may be an option. TLIF, Transforaminal Lumbar Interbody Fusion, a surgery done through the back, may be used when neither ALIF nor LLIF are possible.
What are the benefits of ALIF compared to other procedures?
- ALIF does not require cutting through the back muscles to expose the spine. For this reason, patients tolerate the procedure much easier, have less pain and are able to recover faster
- The spacer inserted in front of the spine provides more powerful manipulation of the vertebrae allowing significant correction of deformity
- Because of the large surface of the spacer, fusion rates are higher after ALIF, compared to other surgeries
- The spinal nerves are not exposed during the ALIF, thus, the risk of nerve damage is smaller
How do I know if ALIF is right for me?
The spine levels at L4-5 and L5-S1 are most commonly addressed with ALIF. If you have a kind of pathology at those levels that may require fusion, ask your surgeon if ALIF is an option.