Posterior corrective surgery for moderate to severe focal kyphosis in the thoracolumbar spine: 57 cases with minimum 3 years follow-up

To evaluate the radiological and clinical outcomes of the corrective surgery for patients with moderate to severe focal kyphosis in thoracolumbar spine. Fifty-seven patients with moderate to severe focal kyphosis of the thoracolumbar spine underwent apical segmental resection osteotomy with dual axial rotation correction at our hospital. There were 30 male and 27 female patients. The mean age was 34.3 years. The kyphosis level radiographs were obtained from each patient before surgery, immediately after surgery and at follow-up. Local kyphosis and scoliosis Cobb angles were measured. Full-spine standing radiographs were obtained before surgery and at follow-up, and the spine sagittal and coronal balance were evaluated. The height of patients, the Frankel grading system for neurological functions, the Oswestry disability index for life quality, the visual analogue score for back pain and the patient satisfactory index for satisfaction to surgery were applied before surgery and at follow-up. The radiological and clinical outcomes were further analyzed in different sub-groups of patients according to etiology, severity of kyphosis, age, level of kyphosis apex, Frankel grade before surgery, and complications. The average follow-up time of patients was 46.1 months. The average kyphosis angle reduced from 94.6° before surgery to 31.0° immediately after surgery, and remained at 34.4° at follow-up. The sagittal balance of the spine, height of patients, Frankel grading, Oswestry disability index and visual analogue score were improved. The patient satisfactory index (PSI) showed a satisfied rate of 91.2%. The correction rate was significantly higher in patients with kyphosis angle less than 95° and age less than 35 years. The clinical improvement rate was significantly higher in patient with kyphosis apex at lower thoracic spine or thoracolumbar segment, Frankel grade E before surgery and no complication group. The incidence of intra-operative and early stage complications was 38.6%, and the incidence of instrumentation failure was 10.5%. The most severe complication was transient spinal cord injury, and the incidence was 7.0%. All complications got good relief after appropriate intervention. Apical segmental resection osteotomy with dual axial rotation correction is an effective procedure to treat moderate to severe focal kyphosis, the prevention of serious neurological complications is fundamental to achieve the ideal clinical results.