Blog Post: Low-Grade Spondylolisthesis (Part 2)                                                               8-9-2021

To restate, a Low-Grade Spondylolisthesis is one which is a Meyerding Grade 1 or 2.

This means the vertebra has slipped forward up to 50% of the vertebral body. To use a football analogy it hasn’t crossed the 50-yard line. Below is a Grade 2.

We typically call spondylolistheses “slips”.

 

What is the most common symptom for Low-Grade slips? Just like spondylolysis/pars fractures, the main symptom for Low-Grade slips is low back pain which worsens with activities.  There is a wide range of symptoms, from no pain to severe disabling pain. 

Are there other symptoms? At times there will be nerve root pain, or sciatica down one or both legs.  This type of pain is usually not constant, but more episodic, and worsens with more stressful activities, such as sports.  If present, this type of pain can be described as “shocky” but also people report decreased sensation or numbness in part of the leg.

So how do we treat Low-Grade slips?  There are several factors which must be considered: previous treatment, length of symptoms, type and severity of symptoms, and how symptoms interfere with activities (sports and activities of daily living).

1.      The first intervention is pain management (over-the-counter medications), activity modification, and physical therapy for paraspinal and core muscle strengthening.  These interventions can be continued long-term, and we discussed these interventions in the previous posts on spondylolysis.

2.      If all nonsurgical management fails to adequately relieve the back +/- leg pain, then surgery may be an option.

What is “surgery” for a Low-Grade Spondylolisthesis? The main goal is to halt the slip progression and to fuse the slipped vertebra to the vertebra on which it is slipping.

The below case is how I generally treat Low-Grade slips surgically:

 

There is a midline incision on the low back

The spine is exposed

Since most of the surgical cases are the isthmic type (have pars fractures), the loose posterior elements are removed, which is called a Gill laminectomy.

The nerve roots are identified and decompressed if necessary.

Pedicle screws are placed into the two vertebra to be fused.

 

The disc space is opened up, from the back and the disc is removed.

To improve the stability of the one-level fusion, a cage is placed between the vertebral bodies (where the disc was before removal) and bone is also placed in the disc space.  This also allows the vertebra to be fused in the front.

The slip MAY be reduced.

Rods are placed (one on each side) to stabilize the vertebra.

Bone graft is placed to get a fusion in the back of the spine.

The surgical wound is closed over a drain (which evacuates blood which collects in the surgical site).