ALIF: Anterior Lumbar Interbody Fusion: Overview
ALIF is generally used to treat back or leg pain caused by degenerative disc disease. The surgeon will stabilize the spine by fusing vertebrae together with bone graft material.
The procedure is performed through a three- to five-inch incision on the stomach. Two common approaches are over the center of the stomach or slightly to the side.
STEP 1: Disc Removed
The damaged disc is partially removed. Some of the disc wall is left behind to help contain the bone graft material.
STEP 2: Implantation
A metal cage implant filled with bone graft is placed in the empty disc space. This realigns the vertebral bones, lifting pressure from pinched nerve roots.
STEP 3: Vertebrae Secured
In some patients, this will be enough to secure the vertebrae. For others, the surgeon may need to implant a series of screws and rods along the back of the spine for additional support.
STEP 4: End of Procedure
Over time, the bone graft will grow through and around the implants, forming a bone bridge that connects the vertebra above and below. This solid bone bridge is called a fusion
ALIF surgery potential risks and complications
There is a major risk that is unique to the ALIF approach. The procedure is performed in close proximity to the large blood vessels that go to the legs. Damage to these large blood vessels may result in excessive blood loss. Quoted rates in the medical literature put this risk at 1% to 15%.
For males, another risk unique to this approach is that approaching the L5-S1 (lumbar segment 5 and sacral segment 1) disc space from the front has a risk of creating a condition known as retrograde ejaculation. There are very small nerves directly over the disc interspace that control a valve that causes the ejaculate to be expelled outward during intercourse. By dissecting over the disc space the nerves can stop working, and without this coordinating innervation to the valve, the ejaculate takes the path of least resistance, which is up into the bladder. The sensation of ejaculating is largely the same, but it makes conception very difficult (special harvesting techniques can be utilized). Fortunately, retrograde ejaculation happens in less than 1% of cases and tends to resolve over time (a few months to a year). This complication does not result in impotence, as these nerves do not control erection.
Apart from the risk to the bowel, the other risks of ALIF are the same as other fusion techniques (non-union, re-operation, etc).
It is important to note that with any type of spine fusion surgery, there is a risk of clinical failure (meaning that the patient's pain does not go away) despite achieving a successful fusion.