Posterior vertebral column resection(PVCR) corrective surgery for moderate to severe focal kyphosis/kyphoscoliosis in the thoracolumbar spine

English Keywords:Focal kyphosis  Posterior vertebral column resection  Thoracolumbar kyphoscoliosis

English Abstract:

  【Abstract】 Objectives: To evaluate the radiological and clinical outcomes of the corrective surgery for patients with moderate to severe focal kyphosis/kyphoscoliosis in thoracolumbar spine. Methods: 68 patients with moderate to severe focal kyphosis/kyphoscoliosis of the thoracolumbar spine underwent posterior vertebral column resection(PVCR) at our hospital. There were 37 males and 31 females, with a mean age of 36.89±15.38 years. There were 45 patients with lower extremity neurological symptoms before operation, preoperative Frankel classification was as follows: 33 cases of grade D, 9 cases of grade C, 2 cases of grade B, and 1 case of grade A. The kyphosis level radiographs were obtained from all patients preoperatively, immediately postoperatively and at final follow-ups. Local kyphosis and scoliosis Cobb angles were measured. Full-spine standing radiographs were obtained before surgery and at follow-ups, and the spine sagittal and coronal balances were evaluated. The Frankel grading system for neurological functions, the Oswestry disability index(ODI) for life quality, the visual analogue score(VAS) for back pain and the patient satisfactory index(PSI) for satisfaction to surgery were applied before surgery and at follow-ups. 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 factors influencing the improvement rate of follow-up ODI score were analyzed by multiple regression. Results: The average follow-up time of patients was 41.47±4.68 months. The average kyphosis angle reduced from 94.14°±22.57° before surgery to 31.92°±16.79° after surgery, and was 34.60°±18.09° at final follow-up, the correction rate of kyphosis was (64.26±15.13)%. The average scoliosis angle of 21 patients reduced from 37.36°±26.19° to 13.21°±14.72° after surgery, and was 14.33°±14.93° at final follow-up, the correction rate of scoliosis was (69.70±28.44)%. At final follow-up, Frankel classification was improved in 29 patients, 3 patients were raised from grade A or B to C, 5 patients from grade C to D, 1 patient from grade C to E, and 21 patients from grade D to E. The sagittal balance of the spine, Frankel grading, ODI and VAS scores were improved. The PSI showed a satisfied rate of 91.2%. The correction rate was significantly higher in patients with kyphosis angle less than 95° and aged less than 35 years. The clinical improvement rate was significantly higher in patients with kyphosis apex at lower thoracic spine or thoracolumbar segment, preoperative Frankel grade E and without postoperative complications. The results of multiple regression analysis showed that the smaller the kyphosis angle before surgery, the larger the degree of kyphosis angle correction was, and with Frankel grade D or E comparing with A-C the ODI improvement rate was higher. The instrumentation failure happened in 6 patients and underwent revision surgery. Conclusions: Posterior vertebral column resection(PVCR) is an effective and safe technique for the treatment of moderate to severe focal kyphoscoliosis. Medium- and long-term follow-up results show that satisfactory results of correction and improvement of nerve function could be obtained.