Staged cervical osteotomy:a new strategy for correcting ankylosing spondylitis thoracolumbar kyphotic deformity with fused cervical spine

BackgroundIn patients with cervical ankylosis, the chin-brow vertical angle (CBVA) should be taken into consideration. Usually, the correction of sagittal balance is sacrificed to ensure the patient has a horizontal visual field. To our knowledge, a staged osteotomy strategy for ankylosing spondylitis kyphotic deformity with an ankylosed cervical spine has not been reported before. The aim of this study was to describe a new surgical strategy with emphasis on sagittal balance and gaze angle in correction of kyphotic deformity with a rigid cervical spine in ankylosing spondylitis thoracolumbar kyphotic deformity.MethodsA 36-year-old man has severe thoracolumbar kyphosis accompanied with cervical hyperlordosis caused by ankylosing spondylitis. A two-stage surgery planning was managed. For the first stage, an interrupted two-level osteotomy was performed at the thoracolumbar area. After surgery, sagittal imbalance was corrected but the CBVA was - 21.7 degrees. Cervical osteotomy was performed for the second stage. A flexion osteotomy was performed at C7, using anterior-posterior-anterior approaches.ResultsBoth sagittal imbalance and gaze angle of the patient were improved markedly. The osteotomy sites were documented fused. Complications were not observed during and after operation.ConclusionsThe aim of osteotomy for ankylosing spondylitis is to reestablish sagittal balance and improve forward gaze and the visual field. A staged cervical osteotomy is an alternative to reduce cervical lordosis to obtain a normal gaze angle. An anterior-posterior-anterior approach is recommended.