Comparison of the clinical effect in ankylosing spondylitis-related kyphosis between one-level vertebral column decancellation and two-level pedicle subtraction osteotomy

English Keywords:Ankylosing spondylitis  One-level vertebral column decancellation  Two-level pedicle subtraction osteotomy  Comparative analysis

English Abstract:

  【Abstract】 Objectives: To investigate the surgical outcome differences of ankylosing spondylitis(AS)-related kyphosis between one-level vertebral column decancellation and two-level pedicle subtraction osteotomy. Methods: From January 2007 to March 2013, 33 patients(31 males and 2 females) with an osteotomy angle between 40° and 65°, and with an average age of 35.2 years(19-56 years) were reviewed. The thoracolumbar kyphosis angle was 42.3°±15.2° and the lumbar lordosis angle was 4.4°±16.4°. Group A included 15 cases who underwent one-level vertebral column decancellation, and group B included 18 cases who underwent two-level pedicle subtraction osteotomy. The thoracic kyphosis, thoracolumbar kyphosis, lumbar lordosis, sagittal vertical axis, pelvic incidence, pelvic tilt, sacral slope, osteotomy angle, Scoliosis Research Society(SRS)-22 and Oswestry disability index(ODI) score at the pre- and post-operation were recorded between 2 groups. The observational indexes before and after surgery as well as the differences of the observational index variation between group A and group B were compared, respectively. Results: The osteotomy sites of group A included 1 in T12, 6 in L2 and 8 in L3, respectively. Osteotomy angle ranged from 46.7° to 64.2°(53.6°±6.7°). The osteotomy sites of group B included 13 in L1 and L3 respectively; 4 in T12, L2 and 1 in T12 and L3 each. Osteotomy angle ranged from 45.1° to 63.9°(55.6°±6.0°). The fixed segment in the proximal and distal segments extended at least two vertebral bodies, the vertebral body between osteotomy sites in group B must be fixed. The neurological complication was not noted in 2 groups after operation. The thoracic kyphosis, thoracic kyphosis, lumbar lordosis, sagittal vertical axis, pelvic tilt, sacral slope, SRS-22 and ODI of two groups improved significantly(P<0.05) after operation except of the thoracic kyphosis of group A(P>0.05). The differences of observational index variation between group A and group B showed no statistical significance(P>0.05) except of the changes of thoracic kyphosis, peri-operative bleeding and operation time(P<0.05). Conclusions: One-level vertebral column decancellation and two-level pedicle subtraction osteotomy have similar outcomes for AS patients with the osteotomy angle between 40° and 65°. While for sagittal balance and improvement of the quality of life, one-level vertebral column decancellation is more satisfactory.