Clinical Application and Exploration on Steps Progressively Corrections and Gradual Shortening Combined with Total Spinal Osteotomy for Angular Kyphosis—Basic Research and Clinical Application

Introduction: This study is designed to explore the biomechanical principles of posterior bilateral pedicle screw on steps progressively and tight closure on every step for severe angular kyphosis and the indication conditions and clinical pathways of above new technique. Materials and Methods: A total of 90 patients have severe angular kyphosis, 37 males and 53 females, with an average age of 47 years. All patients were treated with posterior bilateral pedicle screw and step tight closure for gradual shortening and orthopedic technology. Results: Average intraoperative blood loss was 2089 ml. Average operation time was 326 minutes. Kyphotic angle changed from 90.1° averagely preoperatively to 41.6° averagely postoperatively with an improvement rate of 65%. The distance from C7 plumb line to posterior upper edge of the S1 vertebral body was averagely 5.2 mm postoperatively, with a correction rate of 73%. Neurological complications occurred in 2 cases, accounting for 6%. Non-neurological complications occurred in 2 cases, accounting for 6%. Anatomical parameters were significantly improved postoperatively (P < 0.05). All patients were averagely followed up for 28 months. Segments undergoing osteotomy achieved bone fusion, without loss of orthopedic angle. Conclusions: The orthopedic technology of bilateral pedicle screw and step tight closure designed by human physiology and biomechanical principles can protect spinal cord cells from injury to the utmost. To choose an appropriate osteotomy plane during pre-surgical planning can make the repair results closer to the normal function of the spine. Intraoperative nerve root protection, full release and bone graft fusion are effective safeguards to ensure kyphosis correction and to avoid spine lateral offset.