It's All in the Details: The Specifics of an Interbody Fusion

Week 3

In my very first blog post, I introduced that I will be analyzing Minimally Invasive Spine Transforaminal Lumbar Interbody Fusion (MIS TLIF) for my Senior Research/AP Research Project. So what is exactly is a lumbar fusion?

The basic definition of a lumbar fusion surgery is a procedure that joins or fuses two or more vertebrae. Spinal fusion surgeries are used to treat or help alleviate pain caused by a variety of spinal pathologies like Degenerative Disc Disease, Spondylolisthesis, Neurogenic Claudication, and more. There are multiple ways a lumbar fusion can be performed, but the approach ultimately depends on the patient’s condition and area of pain. For example, an Anterior Lumbar Interbody Fusion (ALIF), a Posterior Lumbar Interbody Fusion (PLIF), an Extreme Lateral Interbody Fusion (XLIF), or a Minimally Invasive Transforaminal Lumbar Interbody Fusion (MIS TLIF) can be performed. Moreover, a spinal fusion isn't limited to the lumbar spine, vertebrae can be fused on cervical and thoracic spine as well. As aforementioned above, the location of the damaged disc (in conjunction with the symptoms) helps the surgeon decide where to make the incision/direct the surgery. An ALIF, PLIF, and XLIF all are surgeries used to replace a damaged intervertebral disc with a cage filled with bone graft. On the other hand, TLIF is a bit more complex.

For the specific purposes of my blog, we will be considering the contexts and implications of these surgeries within the lumbar spine as this is the part of the spine where lordosis occurs. In this next section, I provide short summaries of these procedures and how they differentiate from MIS TLIF.

Anterior Lumbar Interbody Fusion (ALIF)

ALIF is commonly performed on a very specific location on the lumbar spine, the L4-L5 vertebrae or L5-S1 portion. According to Spine Surgery: Techniques, Complication Avoidance, and Management, one of the texts books Dr. Nicol loaned me, an ALIF procedure "allows for restoration, or at least improvement, of normal lumbar lordosis." In addition, ALIF is a more favorable procedure compared to PLIF because there is a lower complication rate. I won't go into too much specifics about ALIF, but I included this video because it demonstrates the wide variety of spinal procedures and techniques.

Click here to watch the video that describes an ALIF.

Posterior Lumbar Interbody Fusion (PLIF)

PLIF is very similar to ALIF. Instead of performing the surgery from the ventral side of the body, it is performed from the dorsal side. (It's pretty intuitive.) According to Spine Surgery: Techniques, Complication Avoidance, and Management, PLIF gained popularity in the mid-twentieth century due to its creator, neurosurgeon Ralph Cloward. Initially, PLIF resulted in higher fusion rates, but more complications like blood loss, dural injury, and more. With time, better instrumentation allowed the surgery to become more successful. However, with PLIF, the thecal sac and nerves have to be pulled aside to get to the disc, amplifying the likelihood for damaging the nerve roots or the dura mater.

Click here to watch an animated PLIF.

Extreme Lateral Interbody Fusion (XLIF)

XLIF is very similar to the aforementioned spinal fusions above. Unlike ALIF or PLIF, XLIF cannot be performed on L5-S1 or L4-L5 (in some cases) . Moreover, the surgery is performed from the side of the body.

Click here to watch XLIF.

Transforaminal Lumbar Interbody Fusion (TLIF)

A traditional TLIF is performed posteriorly. This approach fuses the spine together with pedicle screws and rods to help fuse the spine together. A bone graft is inserted between the vertebrae and along the back the vertebrae because parts of the vertebrae have to be removed in order to perform surgery on the damaged discs. Eventually the bone graft will create a "bone bridge" between the damaged vertebrae.

Click here to watch TLIF.

Minimally Invasive Spine Surgery

Minimally Invasive Spine surgery is a procedure that uses smaller incisions than traditional open back surgery. This approach decreases damage to muscles and ligaments around the spine by utilizing equipment like endoscopes, microscopes, and retractors. Moreover, a minimally invasive approach is associated with less blood loss, faster recoveries, and increased patient satisfaction.

Here is a short video introducing the MIS technique featuring Dr. Jeffrey J. Larson, M.D., my external advisor:

Here is a MIS TLIF Video also featuring Dr. Larson:

I hope that you found this blog post helpful!

Until next time,

Hannah


P.S. this weeks yoga pose is extended puppy pose.