Comparing outcomes for single-segment vertebral column decancellation performed at different vertebras in ankylosing spondylitis-an observational study.

BACKGROUND

The surgical procedure of vertebral column decancellation (VCD) has been increasingly performed in orthopaedic surgery for those with spinal deformity. To investigate the results of single-segment VCD performed at different vertebra for correcting thoracolumbar kyphosis in ankylosing spondylitis (AS) and to guide the osteotomy strategy.

METHODS

Eighty-six AS patients (77 males, 9 females) having thoracolumbar kyphosis underwent single-segment VCD (ranging from T12 to L3) between January 2016 and September 2019 were enrolled and divided into four groups according to the osteotomy vertebra: T12 in 9 cases (Group A), L1 in 15 cases (Group B), L2 in 47 cases (Group C), and L3 in 15 cases (Group D). Demographics, operational data, radiological and clinical data were compared among the four groups.

RESULTS

All patients had significant improvements in spinopelvic alignments and health-related quality of life after correction surgeries. Having the similar demographics, patients in the group C obtained the maximum local kyphosis and global kyphosis correction of 45.05° ± 9.07° (P < 0.001) and 43.42° ± 11.24° (P < 0.001) respectively. However, those in the group A had the largest correction in thoracic kyphosis (41.88° ± 9.57°) and chin-brow vertical angle (24.74° ± 6.38°) respectively (P < 0.001). Moreover, the VCD of L2 or L3 would result in much larger correction in lumbar lordosis and sagittal vertical axis than those in the group A and B respectively (P < 0.001), patients in the group A and B suffered from much higher incidence of complications perioperatively although (P = 0.043).

CONCLUSION

Single-segment VCD performed among thoracolumbar segments can effectively restore spinopelvic alignments and improve the health related quality of life for AS patients with thoracolumbar kyphosis deformity. Moreover, L2 may be the optimal osteotomy vertebra for those patients.

TRIAL REGISTRATION

Clinical trial number: not applicable.

LEVEL OF EVIDENCE

III, therapeutic study.