Cervical spinal canal stenosis: the differences between stenosis at the lower cervical and multiple segment levels

Area of Science:

• Orthopedics
• Neurosurgery
• Radiology

Background:

• Cervical spondylotic myelopathy typically affects lower cervical segments.
• Stenosis at upper cervical segments is less common, suggesting different pathogenetic mechanisms.

Purpose of the Study:

• To investigate differences in the development of cervical canal stenosis at various spinal levels.
• To identify factors contributing to upper versus lower cervical segment stenosis.

Main Methods:

• Positional MRI in a weight-bearing position was performed on 295 symptomatic patients.
• Patients were grouped based on stenosis location: C3-4, C5-6, or both.
• Evaluated parameters included age, canal diameter, disc degeneration, cord compression, and mobility.

Main Results:

• Upper cervical stenosis (C3-4) involved C3-C4 pedicles; lower (C5-6) and two-level stenosis involved C4-C6 pedicles.
• Two-level stenosis group showed significantly smaller sagittal canal diameters (except C7) compared to the lower segment group.
• Developmental morphology of the cervical canal influences stenosis development at different levels.

Conclusions:

• Distinct pathogenetic processes underlie cervical canal stenosis at C3-4, C5-6, and multi-level segments.
• Individuals with sagittal canal diameters <13mm face higher risk for upper cervical stenosis, particularly following lower segment stenosis.