Blog Post: High-Grade Spondylolisthesis (Part 5) 8-29-2021
This is Part 5 on Spondylolistheses and we have gone from the mild deformities and progressing to the severe grades.
In this post we will present a Type 5 High Grade deformity. This means the patient is compensating for the spondylolisthesis slippage, by rolling the pelvis backwards. In the Type 5 deformities it means the patients successfully compensate and stay globally balanced, so they are not leaning forward or backwards.
The case we will present is one of a 16-year old female, who was having low back pain for 2-3 years which was shooting down both of her legs, right more than left leg. In addition she was tripping frequently, as she was having difficulty lifting her foot up. This happens in High-Grade slips, as the nerve root which permits us to lift our foot up gets pinched and may not work normally.
The below figure focuses on the radiographic deformity. The numbers on the slide are very technical, but are important when we diagnosis, classify and plan surgery for this problem. For this blog post we will not discuss these numbers.
Rather look at the middle 2 x-rays, especially the one third from the left with the red arrow. The L5 vertebra should be sitting on top of the S1 vertebra, but it has slid forward and down.
Below is the MRI of the deformity.
The yellow arrow is pointing at the nerve roots which can be pinched as the L5 vertebra slips forward and down on S1.
Since this is an unbalanced patient, we needed to partially reduce L5 on S1. We don’t want to fully reduce the slip, as the nerve roots (yellow arrow above) can be stretched too much and not work normally. If this happens the patient may not be able to lift her foot up, making walking difficult and need to wear a brace on her foot/ankle long-term. By partially reducing the deformity, we can balance the spine and not cause a nerve root problem (or muscle weakness).
Again we place a cage between L5 and S1 to give support after we removed the disc, and to permit a fusion to happen between L5 and S1 in the front of the spine.
Since there are huge forces to reduce and hold the spine in its new position, the use of iliac screws (green arrow) is necessary.
After surgery this patient did not have any nerve root problems (no muscle weakness) and her back and leg pain has resolved. The below figure is now 1 year after surgery and the red arrow shows a robust, thick fusion mass between L5 and S1 (which incorporates the cage).
This is the last post on spondylolisthesis, for now.
If you have questions let me know! This is a complicated problem which is infrequently cared for by most pediatric spine surgeons.