Background/Purpose:

Ankylosing spondylitis is chronic inflammatory arthritis with ligament ossification in spine such as ant. longitudinal ligaments, post. longitudinal ligaments, or other several ligaments around spine joints. We generally use mSASSS to evaluate progression of ossification which method only calculate amount of ossification in ant. longitudinal ligament. But there has not been known which ligaments are ossified most commonly.

We performed whole spine CT scan in patients with ankylosing spondylitis to analyze the frequency of ligaments ossification according to the sites of spine.

Methods:

This is a retrospective chart review study. We enrolled the patients who were diagnosed as ankylosing spondylitis by modified NY criteria in our hospital. Among these patients, we analyzed the male patients who had been performed by whole spine CT scans in ages between 40 and 45. Total 119 patients were enrolled. We analyzed the frequency of ossification in ant. longtudinal ligaments, post. longitudinal ligaments, ligamentum flavum, ligaments around facet joints, interspinous ligaments, supraspinus ligaments and annulus fibrosus according to C, T and L spine.

Results:

The most frequent ossification site was lateral side of annulus fibrosus in T spine (68.9%). Even regardless of C, T, L spine, ossification of lateral side in annulus fibrosus was also the most frequent site (157 sites). Second common ligaments ossified were ant. longitudinal ligaments (142 sites) and third common ligaments were ligaments around facet joints (109 sites). According to spine, the ligaments of T spine were the most common ligaments ossified (252). The ligaments in L spine were second common ligaments ossified (177). Interestingly ossification in the ligaments around L spine did not developed, but developed in T spine in 27 patients (22.7%). This is very important finding because ossification in the ligaments around T spine is not included in mSASSS method which method is used to evaluate disease progression in ankylosing spondylitis at present. Ossification in ant. longitudinal ligaments was strongly statistically correlated with ossification in ligaments around facet joints in L spine strongly (p=0.00. r=0.547).

Conclusion:

Ligaments around T spine were most commonly ossified in ankylosing spondylitis and we need to find new method to evaluate of ossification in T spine.

« Back to 2017 ACR/ARHP Annual Meeting

ACR Meeting Abstracts - https://acrabstracts.org/abstract/frequencies-of-ligament-ossification-in-patients-with-ankylosing-spondylitis-according-to-several-ligaments-around-spine-by-whole-spine-ct-scan/