Facet Effusion-Incorporating Grading System: A Modified Magnetic Resonance Imaging-Based Classification That Enhances...

Area of Science:

• Radiology
• Orthopedics
• Spinal Surgery

Background:

• The conventional Lee classification for lumbar foraminal stenosis (FS) lacks predictive power for surgical intervention.
• Segmental instability, indicated by facet effusion, is a crucial factor in FS progression.

Purpose of the Study:

• To develop a novel MRI grading system for lumbar FS.
• Incorporate facet effusion into the grading system to improve prediction of surgical treatment needs.

Main Methods:

• Retrospective review of 235 patients with lumbar FS (2011-2017) with ≥5 years follow-up.
• Assessed FS severity using conventional MRI grading and a modified system including facet effusion.
• Utilized survival analysis (Kaplan-Meier, log-rank) and Uno's C-index to compare grading systems' predictive ability.

Main Results:

• The modified grading system showed a significant difference in surgical treatment survival between grades (p < 0.001), unlike the conventional system (p = 0.104).
• Uno's C-index improved from 0.69 to 0.73 after incorporating facet effusion.
• 63 out of 235 patients underwent surgical treatment during the mean 8.1-year follow-up.

Conclusions:

• The Facet Effusion-Incorporating Grading System demonstrates superior predictive value for surgical treatment in lumbar FS.
• This novel MRI grading approach offers enhanced discriminatory ability compared to the conventional Lee classification.
• The inclusion of facet effusion in MRI assessment is vital for predicting surgical intervention in lumbar FS.