J Korean Soc Spine Surg.  2014 Sep;21(3):116-122. 10.4184/jkss.2014.21.3.116.

Clinical Results And Prognostic Factors for Thoracic Myelopathy Caused by Ossification of Yellow Ligament after Surgical Treatment

• Kim WJ
• Song DG
• Park KY
• Koo JY
• Kwon WC
• Park KH
• Choy WS

• KMID: 2144773
• DOI: http://doi.org/10.4184/jkss.2014.21.3.116

Abstract

STUDY DESIGN: Retrospective study.
OBJECTIVES
We analyzed the clinical results of thoracic myelopathy caused by ossification of yellow ligament (OYL) and to explore prognostic factors after surgical treatment. SUMMARY OF LITERATURE REVIEW: Thoracic myelopathy due to OYL is difficult to treat; surgery is considered as treatment of choice. However, studies of the clinical results and prognostic factors are few due to its rare presentation.
MATERIALS AND METHODS
Twenty six patients who had surgery for thoracic myelopathy caused by OYL were evaluated from February 2002 to April 2012. We describe the analysis of the clinical results after surgery and prognostic factors.
RESULTS
Modified Japanese orthopedic association (JOA) score was recorded in all patients by 5.7+/-1.3 points (range, 2-9 points) preoperatively, 7.8+/-1.7 points (range, 4-10 points) postoperatively, and 8.4+/-2.1 points (range, 5-11 points) at final follow-up. Hirabayashi recovery rate was recorded by 60.2+/-20.2% (range, 45.5-72.0%) postoperatively, 64.5+/-17.3% (range, 50.2-75.1%) at final follow-up. The Visual Analogue Scale (VAS) score was also improved by 7.6+/-1.8 points (range, 7-10 points) preoperatively, 4.5+/-1.3 points (range, 3-6 points) postoperatively, and 3.8+/-1.6 points (range, 2-5 points) at final follow-up. Both modified JOA score and VAS score improved significantly (p<0.05). In prognostic factor analysis, OYL type on CT axial image, duration of symptom, and preoperative severity of myelopathy was significant (p<0.05).
CONCLUSION
We showed the effectiveness of surgery on patients who suffer from thoracic myelopathy caused by OYL and that OYL type identified by CT axial image, duration of symptom, and preoperative severity of myelopathy were significant prognostic factors.

Keyword

Ossification of yellow ligament; Thoracic myelopathy; Clinical result; Prognostic factor

MeSH Terms

Asian Continental Ancestry Group
Follow-Up Studies
Humans
Ligaments*
Orthopedics
Retrospective Studies
Spinal Cord Diseases*

Figure

• 

  Fig. 1. A 57-year-old man suffered from thoracic myelopathy T2-3-4 by OYL. (A) This CT sagittal image shows OYL with protrusion into the spinal canal at T2-3 and T3-4 level (arrow). (B) CT axial image displays localized type of OYL with spinal canal encroachment (arrow). (C) T2-wighted MRI sagittal image demonstrates OYL of beak type which encroaches spinal canal on T2-3 and T3-4 level. (D) He underwent surgery of T2-3-4 posterior decompression and postoperative CT sagittal image shows well-decompressed spinal canal.

• 

  Fig. 2. A 66-year-old man had thoracic myelopathy T10-11 by ossification of yellow ligament. (A) CT sagittal image demonstrates OYL lesion between T10 and T11 level (B) T2-weighted MRI sagittal image shows hypointense signal of OYL with beak type on T10-11 level and intramedullary hypertense signal change on T11-12 level just beneath the level of lesion. (C) Preoperative plain lateral radiograph shows OYL with projection to the spinal canal at T10-11 level (arrow). (D) He had an operation of T10-11 posterior decompression and posterolateral fusion. The patient had to get a wide laminectomy including facet joint because of large size of OYL. This is the reason he had to have a surgery of fusion.

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