Stand alone ALIF on a male

By your report, you have an isthmic spondylolisthesis at L5-S1 (“if I’m still in pain after the surgery that he can bring me back in to do a decompression of the pars defect and also add screws and rods for more support”).

I generally am not a fan of the anterior approach for lumbar spine disorders (ALIF). This is due to two problems associated with the anterior approach surgery and a separate problem with your specific disorder.

In any anterior approach to the lumbar spine, muscles in the belly are cut and this can lead to a muscular hernia in the belly wall. In addition, moving the intestines (which has to be done to get to the anterior spine) can occasionally lead to adhesions and sequella.

The second problem is found with males. There is a 4% chance of retrograde ejaculation. This is due to injury to the sympathetic nerves which descend immediately to the side of the lumbar vertebra. Retrograde ejaculation means that semen will eject into the bladder and not out the end of the penis.

The third problem with an ALIF for an isthmic spondylolisthesis is that there already is a defect in the posterior elements. The ALIF does provide some stability with the screw in cage, but without the stability of the posterior elements (due to the pars fractures-see website), this construct is not as stable as with a posterior approach.

If he suspects that there is a chance of continued pain and that he will need to go posteriorly in a second surgery to stabilize the surgery, why not do this entire process posteriorly at one sitting? A TLIF will produce an anterior fusion like your surgeon proposes along with the ability to decompress the nerves in the back of the spine and put in posterior instrumentation which will make the surgery very stable from the beginning.

I don’t want to full dissuade you as there is a reasonable chance that an ALIF will work well but the chances of success are less than with a TLIF.

I assume that if the surgeon noted that he might need to “roll someone over during the same surgery and putting in the back up screws and rods during the same surgery” is that if he performs the anterior approach for an ALIF and finds greater instability than he assumes is present, he will need to perform a poster instrumentation and fusion at the same setting.

Dr. Corenman

It is hard for me to understand that most of the surgeons would select an ALIF over a TLIF. Have you been consulting with only neurosurgeons?

When you indicate a “lateral fusion”, I assume you mean a posterolateral fusion. The difference is that a lateral fusion (DLIF or XLIF) is performed through the side of the body and will not work for L5-S1 as the iliac crest prevents access.

The posterolateral fusion is performed only from the back of the spine. Generally this fusion should always be included when the incision is from the back of the spine although I have seen some cases where for some unknown reasons, it was not done.

You want a solid fusion as the primary goal of this surgery. In my opinion, this means prepare all potential surfaces for fusion mass. This means the disc space and both posterolateral regions (called the transverse-alar interval).

The statement that “obtaining the largest fusion bed from ALIF will provide the most support and will not require second surgery. I am told the intervertebral fusion will not be nearly as strong with the smaller TLIF or PLIF cages” is blatantly wrong. The TLIF prepares the disc space just as well as the ALIF and fusion is improved by both instrumentation which stabilizes the spine and by the posterolateral fusion which allows for more surface area for fusion.

I have about a 99% fusion rate using the TLIF procedure and I doubt that the individuals you have talked to have that fusion rate.

Dr. Corenman

So these surgeons have not really been planning an ALIF but really planning a “360” or a variant of a front and back fusion. I have seen this pattern before. The simple “roll you over to put in screws is really a posterior approach and not “simple”.

This begs the question as to why they would plan an ALIF which is a stand alone procedure when they really plan a 360 but without any of the benefit of the posterior approach. If you are going to have a posterior incision and screw placement, why not avoid any of the anterior risks and do the entire surgery from one small incision in the back?

This idea of placing screws in the back without the benefits of a decompression or a fusion of the facets and transverse processes bewilders me. The surgeon is already there, can place screws and still do a fusion as well as a decompression and does nothing but place screws. It makes no sense.

A disc herniation cannot be decompressed from the front without some risk to the nerves and dural sac. It is much better to directly look at the nerves being decompressed and decompress then under direct visualization (see microdisc video to understand this concept) than to attempt to decompress indirectly.

Remember that a solid fusion of the disc space and posterior elements will be strong regardless of the approach. The argument that the anterior fusion is stronger is simply not true. The size of the cage is really not relevant as long as a cage of 6mm or larger is placed.

The pars fractures that caused the isthmic spondylolisthesis separates the facets from the entire vertebra. Preserving the facets will not make a difference in stability, but there are detriments to not removing them.

These facets are great bone graft sources and should be used for graft. Not using them again makes absolutely no sense. This graft can make the difference between a solid fusion and no fusion at all. In addition, there is typically a large spur that grows off the bottom of the pedicle of L5 where the fracture originates. This spur compresses the L5 root and can cause compression if the disc is distracted by a intradiscal cage.

Dr. Corenman