The clinical relevance of the presence of bridging syndesmophytes on kyphosis correction and maintenance following pedicle subtraction osteotomy for thoracolumbar kyphotic deformity in ankylosing spondylitis: a comparative cohort study

Table 1 Radiological comparisons of spino-pelvic sagittal parameters before surgery, before discharge and at a minimum 2-year follow-up

Parameters	Groups	Preoperative	Postoperative	Final Follow-up
SVA(mm)	NBG	147.46 ± 58.92	34.46 ± 37.53*	34.17 ± 35.33
SVA(mm)	BG	174.43 ± 51.59^†	54.03 ± 44.99*	57.28 ± 35.18
SSA(°)	NBG	80.56 ± 16.68	108.36 ± 11.82*	106.18 ± 11.48
SSA(°)	BG	80.81 ± 14.20	104.19 ± 7.95*	103.84 ± 8.37
TPA(°)	NBG	44.41 ± 11.50	17.87 ± 8.54*	21.69 ± 8.71^#
TPA(°)	BG	50.90 ± 12.13^†	26.78 ± 10.11*	27.97 ± 10.30
GK(°)	NBG	66.28 ± 17.80	18.26 ± 10.97*	21.51 ± 10.89^#
GK(°)	BG	71.28 ± 16.14	22.09 ± 17.20*	21.63 ± 14.97
LK(°)	NBG	19.59 ± 10.84	−25.53 ± 8.76*	− 25.67 ± 10.38
LK(°)	BG	13.56 ± 8.50^†	−26.75 ± 7.35*	− 27.09 ± 7.36
TK(°)	NBG	41.87 ± 16.46	37.95 ± 11.87*	42.87 ± 11.56^#
TK(°)	BG	49.69 ± 16.78	46.63 ± 14.62*	44.41 ± 12.92
LL(°)	NBG	3.87 ± 14.39	−40.54 ± 14.06*	− 39.69 ± 12.45
LL(°)	BG	0.22 ± 13.61	−38.44 ± 10.87*	− 38.94 ± 10.80
SS(°)	NBG	7.36 ± 9.21	23.02 ± 9.12*	18.62 ± 10.10^#
SS(°)	BG	8.75 ± 7.53	20.31 ± 6.26*	19.63 ± 6.69
PT(°)	NBG	35.64 ± 8.73	19.46 ± 8.13*	23.44 ± 8.19^#
PT(°)	BG	40.63 ± 10.28^†	26.91 ± 9.42*	28.28 ± 9.59

^†Indicates a statistically significant difference intergroup comparing preoperative values (p < 0.05)
*Indicates a statistically significant difference intragroup comparing preoperative and postoperative values (p < 0.05)
^#Indicates a statistically significant difference intragroup comparing postoperative and final follow-up values (p < 0.05)
SVA indicates sagittal vertical axis, TPA T1 pelvic angle, SSA spinosacral angle, GK global kyphosis, LK local kyphosis, TK thoracic kyphosis, LL lumbar lordosis, SS sacral slope, PT pelvic tilt, BG bridging syndesmophytes group, NBG non-bridging syndesmophytes group

ISSN: 1471-2474