The Radiological Complications of Short-Segment Pedicle Screw Fixation Combined with Transforaminal Interbody Fusion in the Treatment of Unstable Thoracolumbar Burst Fracture: A Retrospective Case Series Study in Vietnam

Figures & data

Figure 1 Measurement of parameters on plain X-rays: (A) shows measurement of the regional kyphotic angle (RA) and vertebral kyphotic angle (VA); (B) shows measurement of percentage of anterior vertebral body height loss (%AVB), which is calculated by the formula: %AVB = 100–2b/(a + c)* 100, where a is the anterior edge height of the vertebra above the fractured vertebra; b is the anterior edge height of the fractured vertebra; and c is the anterior edge height of the vertebra below the fractured vertebra.

Table 1 Demographic Data

Parameters	Hardware Failure (N, [%])			Total
	No	Yes	p value
				N=36
Follow up months	51.0 ± 17.1	64.8 ± 8.3	0.078	53.3 ± 16.7
Age	47.8 ± 12	41.7 ± 9	0.143	46.8±11.7
Gender (%)
Female	16 (44.4)	0 (0)		16 (44.4)
Male	14 (38.9)	6 (16.7)		20 (55.6)
The reasons of trauma
Fall from height	23 (63.9)	5 (13.9)		28 (77.8)
Traffic accident	4 (11.1)	0 (0)		4 (11.1)
Sport accident	3 (8.3)	0 (0)		3 (8.3)
Direct trauma	0 (0)	1 (2.8)		1 (2.8)
Fracture level
T12	4 (11.1)	0 (0)		4 (11.1)
L1	17 (47.2)	5 (13.9)		22 (61.1)
L2	9 (25)	1 (2.8)		10 (27.8)
LSC	6.7 ± 1.1	7.0 ± 0.6	0.493	6.8 ± 1.1

Table 2 Correction Loss of Kyphotic Deformity at Final Follow-Up

Parameters	Pre-Operative	Immediately Post-Operative	Final Follow-Up	Correction Loss
%AVB	49.1	17.3*	27.5^+,**	10.2
VA (^°)	24.6	11.5*	14.4^+,**	2.9
RA (^°)	19.7	8.5*	14.1^+,**	5.6

Notes: *The postoperative versus the preoperative with p-value < 0.05. ⁺The latest follow-up versus the preoperative with p-value < 0.05. **The latest follow-up versus the postoperative with p-value < 0.05.

Table 3 The Prevalence of Hardware Failure

Hardware Failure		N (%)	Total (%)
No		30 (83.3)	83.3
Yes	Screw breakage below fracture level	2 (5.6)	16.7
	Screw breakage above fracture level	3 (8.3)
	Rod pull-out of above screw head	1 (2.8)
	Loss of regional kyphosis angle >10°	0
	Screw loosening	0

Table 4 CT Grading of Interbody Fusion Based on Bridwell’s Criteria

Fusion Grade	N (%)	Numbers of Cases of Implant Failure
Grade I	23 (63.9)	3 cases
Grade II	10 (27.8)	2 cases
Grade III	3 (8.3)	1 case
Grade IV	0	0

Figure 2 Implant failure: (A) breakage of pedicle screws above the fracture level; (B) breakage of pedicle screws below the fracture level; (C) rod pull out of the pedicle screw head.

Figure 3 Good bone union in the patient with hardware failure: (A) preoperative X-ray; (B) postoperative X-ray; (C) final follow-up X-ray with hardware failure; (D) sagittal CT at last follow-up with good bone union.