Change in sagittal plane alignment following surgery for Scheuermann's kyphosis

Study Design Retrospective comparative study. Objective To evaluate changes in sagittal plane alignment in patients with Scheuermann's kyphosis after spinal fusion. Summary of Background Data Although surgery is commonly undertaken in patients with severe Scheuermann's kyphosis for deformity correction, there are limited data regarding the response of spinopelvic parameters and sagittal plane alignment of the spine to surgical treatment. Methods Eighteen consecutive surgical Scheuermann's kyphosis patients were retrospectively reviewed (mean preoperative kyphosis, 76°). Full-length spine films were evaluated for maximal sagittal Cobb angle, thoracic kyphosis, cervical and lumbar lordosis, pelvic parameters, and sagittal plane alignment. Findings were compared with reported literature values in normal patients. Results After surgery, thoracic kyphosis improved significantly, with mean maximum kyphosis improving from 76° to 56° (p =.001). Preoperative cervical lordosis was increased compared with reported normal adolescent values (-35° vs. -5°) and did not significantly change after surgery. Lumbar lordosis decreased significantly after surgery, from -77° to -57° (p =.023). No change was noted in pelvic tilt, sacral slope, or pelvic incidence. Furthermore, there was little improvement in sagittal plane alignment. Preoperatively, 12 of the 18 patients had deviation in sagittal plane alignment greater than 2 cm (5 positive and 7 negative); postoperatively, 11 patients had persistent sagittal imbalance (6 positive and 5 negative). Five patients were noted to have proximal junctional kyphosis and 3 underwent revision surgery for malpositioned screw (1) and loss of distal fixation (2). Conclusions Surgical management of Scheuermann's kyphosis resulted in normalization of thoracic kyphosis and lumbar lordosis. Compared with reported values in unaffected adolescents, cervical lordosis remained increased and most patients had residual sagittal plane imbalance greater than 2 cm on imaging.