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Clinical outcomes for andersson lesion in patients with ankylosing spondylitis by transforaminal thoracolumbar intervertebral fusion surgery.

BACKGROUND
Andersson lesion (AL) is a rare complication of ankylosing spondylitis (AS). Its clinical outcome of surgical treatment needs further exploration.


OBJECTIVE
To evaluate the clinical and radiological outcomes of transforaminal thoracolumbar intervertebral fusion (TTIF) in the treatment of AS patients with thoracolumbar AL.


METHODS
Fourteen patients with thoracolumbar AL who suffered from back pain, spinal instability or kyphotic deformity were retrospectively recruited. The clinical outcomes were evaluated with Visual Analog Scale (VAS) and Oswestry Disability Index (ODI). Radiological outcomes were measured with local kyphotic (LK) angle and general kyphotic (GK) angle.


RESULTS
Before surgical treatment for the AL patients, their VAS score and ODI score was 8.0 ± 0.2 and 64.0 ± 6.9, respectively. After TTIF surgery, VAS score of the patients was improved to 2.4 ± 0.5 (p< 0.01) and ODI score was decreased to 17.0 ± 3.7 (p< 0.01). One patient with neurological deficit showed an improvement in the Frankel grade from C to D and all others were grated E-level before and after surgery. For radiological outcomes, patients' LK angle was reduced from 18.5 ± 7.2 to 11.0 ± 6.4 (p< 0.01) and GK angle was reduced to 38.6 ± 8.8 from 42.8 ± 10.4 (p< 0.01) at the 1-year follow-up.


CONCLUSION
For AS patients with thoracolumbar AL, we propose that TTIF is an effective and safe operative treatment, which can achieve good fusion, satisfactory radiological and clinical outcomes.