INTRODUCTION

Severe fixed thoracolumbar hyperkyphosis represents one of the greatest challenges in spinal surgery. This type of deformity impairs patients’ quality of life because of the often-associated sagittal imbalance. The surgical management of these deformities, because of their null reducibility, requires aggressive surgical management, such as a three-column osteotomy. A pedicle subtraction osteotomy (PSO) is a complex wedge-shaped spinal osteotomy that results in a powerful angular correction, up to 40° in the lumbar spine. Although it has been extensively used in the lumbar spine, the same procedure can be used in the thoracic spine; however, the presence of the spinal cord makes the procedure more demanding. In addition, because of the smaller dimensions of the vertebrae and the different relative sagittal height of the pedicle compared with the vertebral body, thoracic PSOs allow for smaller correction angles compared with lumbar PSOs. Therefore, a simultaneous, double, noncontiguous thoracic PSO may be necessary to gain adequate sagittal correction.

This video presents the surgical correction of severe thoracolumbar hyperkyphosis in adults via two-level noncontiguous thoracic pedicle subtraction osteotomies, analyzing the imaging results in a series of four cases.

MATERIALS AND METHODS

This was a retrospective study. The study included all patients who underwent posterior spinal correction and fusion for severe thoracolumbar hyperkyphosis, with a main thoracic hyperkyphosis greater than 90°, at our institution between January 2016 and June 2019. All the patients underwent one-stage posterior arthrodesis with the use of high-density pedicle screws. All the patients underwent low-dose, high-resolution CT of the spine. A virtual model was then created, and the entry points and the trajectories of the screws as well as the main geometric parameters were set by the surgeon. Customized drill-guides were printed accordingly and then used for screw placement. Sensory- and motor-evoked potentials were monitored. In this case series, all the patients underwent a double noncontiguous thoracic PSO. All the procedures were performed by the same experienced surgeon. All the radiographic measurements to assess deformity correction were obtained by the same experienced surgeon who performed the surgeries. Mean follow-up was 16 months (range, 12 to 48 months). Oswestry Disability Index scores were submitted preoperatively and at the last follow-up to determine patient satisfaction with surgical treatment.

RESULTS

Four patients (three women, one man) were included in the series. The mean patient age was 42.6 years (range, 30 to 52 years). The mean deformity angle improved from 103.7° to 36.4° (64.9% correction rate). Mean thoracic kyphosis improved from 79.1° to 35.5°. Mean pelvic tilt decreased from 38.9 to 25.9. The mean sagittal vertical axis decreased from 16.3 cm to 5.4 cm.

Patients were satisfied with the outcome of surgical treatment. The mean Oswestry Disability Index score decreased from 21.4 preoperatively to 9.3 postoperatively. No major intraoperative and postoperative complications were reported.

DISCUSSION

This technique, although technically demanding, is effective because it allows for powerful correction of the thoracic deformity and restores correct sagittal balance. By dissipating the correction on multiple levels, neurologic risks were lower than those associated with more aggressive techniques, such as vertebral column resection. Another advantage may be a lower risk of pseudarthrosis given the bone-to-bone contact that occurs at the osteotomy level without the use of anterior supports.

CONCLUSIONS

The use of multiple thoracic PSOs is a powerful and safe alternative in the management of severe fixed thoracic hyperkyphosis. Additional studies are necessary to evaluate long-term complications.