Study design <p>Technical case report.</p> Introduction <p>Severe thoracic hyperkyphosis caused by multiple osteoporotic fractures can lead to significant disability. When deformities are rigid, surgical correction may be required. This report describes a rare case of four-level pedicle subtraction osteotomy (PSO) to address a fixed deformity, with focus on technique, outcomes, and complications.</p> Case presentation <p>A 65-year-old female with Scheuermann’s disease developed progressive thoracic hyperkyphosis due to osteoporotic vertebral fractures. Radiographs showed a rigid kyphosis of 130.3°. The patient underwent a two-stage surgery: cement-augmented instrumentation (T2–L3), followed by contiguous PSOs from T6 to T9. Neurophysiological monitoring was used throughout.</p> Results <p>Kyphosis was corrected from 130.3° to 48°. Postoperatively, the patient developed progressive lower limb weakness due to spinal cord kinking. Revision surgery allowed neurological recovery. At two years, radiological parameters remained stable, and the patient reported reduced pain, improved mobility, and restored quality of life.</p> Conclusion <p>Four-level PSO can be an effective treatment for severe rigid thoracic hyperkyphosis in osteoporotic patients. Although technically demanding and associated with potential complications, careful planning and staged correction can result in successful outcomes.</p> Level of evidence <p>IV (Case Report).</p>