Spondylolisthesis and Spondylolysis N039

Current RMA Instruments

Changes from previous Instruments

ICD Coding:

• ICD-10-AM: M43.0, M43.1, Q76.21, Q76.22

Brief description:    

Spondylolisthesis refers to the displacement of one vertebra relative to the one beneath it. This can occur in a forward direction (anterolisthesis) or less commonly, backward (retrolisthesis).

Spondylolysis is a defect or fracture of the pars interarticularis- a small segment of bone that connects the upper and lower facets of a vertebrae. It can be unilateral (one side) or bilateral (both sides), and most often occurs at the L5 level of the lumbar spine, with L4 being the next most common site. This conditio typically arises either as:

• A developmental- defect, usually becoming apparent in childhood (around 8 yrs of age), or a
• A stress fracture, especially in child and adolescent athletes involved in high- repetition hyperextension activities. 

Spondylolisthesis often develops secondary to spondylolysis but it can also occur due degenerative changes (spondylosis) or other less common causes.

Confirming the diagnosis

Diagnosis requires X-ray, CT scan or MRI scan showing forward displacement (anterolisthesis) or backward displacement (retrolisthesis) of one vertebra over the vertebra below. 

The specific type of the condition (evident from the imaging) needs to be considered to apply some of the SOPs factors. See further comments below relating to the diagnosis.

The relevant specialist is an orthopaedic surgeon.

Additional diagnoses covered by SOP

• Anterolisthesis
• Retrolisthesis
• Degenerative spondylolisthesis

Conditions not covered by these SOPs

• Cervical spondylosis *
• Thoracic spondylosis *
• Thoracolumbar spondylosis *

* another SOP applies

Further comments on diagnosis

Types:

• Spondylolytic spondylolisthesis - forward displacement of a vertebra due to bilateral fractures of the pars interarticularis.
• Degenerative spondylolisthesis - displacement of vertebra associated with degeneration of facet joints without pars interarticularis fracture(s).  This form typically presents in older adults with advanced degenerative joint disease.
• Other causes- rarely, spondylolisthesis can occur due to congenital vertebral dysplasia, high impact trauma, osteomyelitis or neoplastic bone involvement.
• Retrolisthesis most commonly affects the cervical spine or lumbar spine and typically occurs in the context of degenerative changes (spondylosis).

Clinical onset

The condition may be asymptomatic and found incidentally on imaging, especially when it develops in early life.  In adolescent athletes, symptoms usually develop gradually as activity- related low back pain, in the form of low back pain, rather than an acute injury.  Spondylolysis or spondylolytic spondylolisthesis is unlikely to present as new onset back pain in adults, particularly those aged 25 or older. In contrast, degenerative spondylolisthesis and retrolisthesis more commonly appear later in life as part of age-related spinal degeneration. 

In asymptomatic individuals, the date of imaging may be considered the date of onset. 

Clinical worsening

Progression may be marked by an increase in the degree of vertebral slippage or displacement. The development of spondylolisthesis on a background of spondylolysis should be regarded as a separate new diagnosis.