Defining Instability in Degenerative Spondylolisthesis: Surgeon Views

Area of Science:

• Spine surgery
• Orthopedics
• Neurosurgery

Background:

• Degenerative spondylolisthesis (DS) treatment decisions often hinge on the definition of spinal instability.
• A lack of consensus on what constitutes instability complicates surgical decision-making for DS.
• Understanding surgeon-defined instability is crucial for standardizing treatment approaches.

Purpose of the Study:

• To investigate the factors surgeons consider when defining instability in grade 1 degenerative spondylolisthesis (DS).
• To assess the treatment preferences of surgeons for both stable and unstable DS.
• To identify key radiographic and clinical parameters influencing the perception of instability.

Main Methods:

• A survey was administered to surgeons to determine their criteria for instability in DS.
• Respondents indicated the significance of static and dynamic translation, angulation changes, and other clinical/radiographic factors.
• Surgeons reported their preferred treatment strategies for stable and unstable DS.

Main Results:

• Dynamic translation was deemed highly influential by 99% of surgeons, while static translation was important to 55%.
• Prevalent cut-offs for instability were 2-4mm dynamic translation, 10-15 degrees angulation change, and significant importance placed on facet angulation, disk height, and patient age.
• While 99% favored fusion for unstable DS, treatment for stable DS varied, with 60% preferring decompression alone and 40% opting for fusion.

Conclusions:

• There is no clear consensus on the definition of instability in degenerative spondylolisthesis.
• Dynamic translation emerges as the most consistently considered parameter for instability.
• Surgical treatment for unstable DS shows consensus for fusion, but approaches for stable DS are more varied.