PMC9168345_01
Preoperative CT images: sagittal view (a) and axial views (b and c). Lines (b) and (c) indicate axial slices shown in b and c, respectively (a). Preoperative magnetic resonance images: sagittal view (d) and axial views (e and f). Lines (e) and (f) indicate axial slices shown in (e) and (f), respectively (d).
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F1
Initial radiographic examination including computed tomography (CT) scan and magnetic resonance imaging showed burst fracture at the L1 level with spinal cord and cauda equina compression, which was classified as AO type B2 with spinous process fracture at L1 and L2 [Figure 1]. In this patient, cranial endplate injury was severe; however, caudal endplate injury was mild [Figure 1].
Postoperative radiographs taken in operating theatre in lying position (anteroposterior view in supine position: a, and lateral view in prone position: b), and taken in standing position 14 days after the first surgery (c). Local kyphosis angle (LKA) between T12 and L2 was 16  in prone position (b) and 32  in standing position (c).
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F2
T12 and L2 levels after partial laminectomy at the T12 and L1 vertebrae for decompression were performed [Figure 2]. Intraoperatively, we tried to fill the vacant space inside the fractured vertebra with hydroxyapatite blocks (Pentax, Tokyo, Japan). The angle between the cranial endplate of T12 and the caudal endplate of L2 (local kyphosis angle: LKA) was 18  preoperatively (supine position) and improved to 16  intraoperatively (prone position, [Figure 2]). LKA was 32  in the standing position [Figure 2], while it was 24  in the lateral lying position.
Anteroposterior (a) and lateral radiographs taken in lateral lying position (b) and in standing position (c) after second surgery (3-above 3-below posterior fixation). Local kyphosis angle (LKA) between T12 and L2 was 22  in lateral lying position (b) and 27  in standing position (c).
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F3
T10 to L4 levels were connected by two rods to reinforce the stability of the screw-rod system [Figure 3].
Coronal reconstruction CT images showing location of rib graft bone and caudal endplate injury. CT images of this patients (Case 1) taken a week (a) and 21 months (b) after anterior fusion surgery, showing mild caudal endplate injury (white arrows in a and b) and unilaterally located graft bones (a, b). The continuity of trabecular bone between T12 and L1 vertebrae were observed 21 months after the surgery (b). CT images of Case 2 in Table 1 taken a week (a) and 14 months (b) after anterior fusion surgery, showing no injury at the caudal endplate and graft bones widely located at the fractured site (c, d), and bony fusion was observed 14 months after the surgery (d). CT images of Case 3 in Table 1 taken a week (e) and 21 months (f) after anterior fusion surgery, showing radiologic findings similar to Case 1 (mild caudal endplate injury [white arrows in e and f] and unilaterally located graft bones). The continuity of trabecular bone at the fractured site was observed 21 months after the surgery (f).
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F4
Subsequently, the T12-L1 disc and a part of the injured L1 vertebra were removed, and autologous rib strut grafts were inserted [Figure 4]. T12-L1 segment was confirmed by CT images [Figure 4]; thus, 24 months after the third surgery, all posterior implants were surgically removed. The LKA in the standing position was 28  before removal and 30  11 days after removal [Figure 6]. L1 and L2 vertebrae was observed, as well as between T12 and L1. Loss of lordosis occurred both at the T12-L1 segment (6 ) and L1-L2 segment (6 ), although continuous trabecular bone formation between the T12 and L1 vertebrae was observed before implant removal [Figure 4].
Anteroposterior (a) and lateral radiographs taken in lateral lying position (b) and in standing position (c) after third surgery (single-level anterior fusion). Local kyphosis angle (LKA) between T12 and L2 was 22  in lateral lying position (b) and 29  in standing position (c).
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F5
After the third surgery, the LKA was 22  in the lateral lying position and 29  in the standing position [Figure 5].
Lateral radiographs taken in standing position 21 months (before removal, a), 24 months (after removal, b), and 51 months (final follow-up, c) after the anterior fusion surgery. Local kyphosis angle (LKA) between T12 and L2 was 28  before removal (a), 30  after removal (b), and 40  at the final follow-up (c).
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F6
T12-L1 segment was confirmed by CT images [Figure 4]; thus, 24 months after the third surgery, all posterior implants were surgically removed. The LKA in the standing position was 28  before removal and 30  11 days after removal [Figure 6]. Six months after the removal, LKA in the standing position was 37 , and increased up to 40  at the final follow-up (27 months after removal, [Figure 6]).