Combined percutaneous and open instrumentation for thoracolumbar kyphosis correction by two-level pedicle subtraction osteotomy in ankylosing spondylitis.

backgroundA long global thoracolumbar kyphosis is common in ankylosing spondylitis. Surgical correction of fixed sagittal malalignment by pedicle subtraction osteotomy (PSO) might improve disability and quality of life (QoL). Two-level osteotomies represent major procedures with a risk of hemorrhage. Combined open and minimal invasive surgery has not been described and might be considered. CASE PRESENTATION: A 30-year-old female with ankylosing spondylitis was treated by golimumab and teriparatide. The treatment was stopped during pregnancy which led to vertebral compression fractures and kyphosis of 50° between T11 and L3. A PSO was planned at the kyphotic apex L2. The second PSO was planned at L4 according to the pelvic incidence of 56°, matching with a spinopelvic alignment Roussouly type 3. A derived full balance integrated method was used to calculate the amount of correction. During the first stage surgery, an open approach was performed from L1 to pelvis and combined with percutaneous cement-augmented instrumentation in already fused segments T5-T12, thus reducing perioperative morbidity. A stepwise approach including L2 PSO closure with temporary rods and L4 PSO with final instrumentation was used. Blood loss was estimated around 1100 ml. The patient was able to walk on the second day after surgery. A secondary anterior fusion with LLI cages from L2 to L5 and an ALIF at L5-S1 were performed because of high non-ossified intervertebral disks to reduce the risk for nonunion and rod fractures. At 2-year follow-up, the patient's QoL had significantly improved and full spine radiographs showed stable normalized sagittal parameters.

conclusionThe combined open and percutaneous approach was feasible and might be considered as an alternative option to conventional open surgery when planning major deformity correction in ankylosing spondylitis.