Article Figures & Data
Figures
- Figure 1
The five configurations of the instrumentation in the sacropelvic region (left—posterior view of sacropelvis; right—lateral view of sacropelvis): (a) pedicle screw fixation (PED); (b) PED bilaterally supplemented with S2 alar-iliac (S2AI) screws; (c) PED bilaterally supplemented by a porous fusion/fixation implant (PFFI) in an S2AI trajectory; (d) PED bilaterally supplemented with a triangular titanium implant placed in a sacro-alar-iliac trajectory and by a PFFI in an S2AI trajectory (PFFI-IFSAI); (e) PED bilaterally supplemented by a PFFI placed in an S2AI trajectory and a second PFFI in an SAI trajectory stacked cephalad to that in the S2AI position (2-PFFI). Rods are not shown.
- Figure 2
Predicted ranges of motion with respect to pedicle screw of L5-S1 and sacroiliac joints in flexion-extension (left), lateral bending (middle), and axial rotation (right) for the 4 instrumented configurations (S2AI, PFFI, PFFI-IFSAI, and 2-PFFI). Refer to Table 1 for model descriptions and abbreviations.
- Figure 3
Maximal stresses in the left S1 pedicle screw predicted for the 5 instrumented configurations (PED, S2AI, PFFI, PFFI-IFSAI, and 2-PFFI). “flex”: flexion; “ext”: extension; “lb (ipsi)”: lateral bending in the ipsilateral direction (the same side of the implant of interest); “lb (contra)”: lateral bending in the contralateral direction; “ar (ipsi)”: axial rotation in the ipsilateral direction (the same side of the implant of interest); “ar (contra)”: axial rotation in the contralateral direction. Refer to Table 1 for model descriptions and abbreviations.
- Figure 4
Maximal stresses in the left implants placed in an S2 alar-iliac (S2AI), trajectory predicted for 4 instrumented configurations (S2AI, PFFI, PFFI-IFSAI, and 2-PFFI). “flex”: flexion; “ext”: extension; “lb (ipsi)”: lateral bending in the ipsilateral direction (the same side of the implant of interest); “lb (contra)”: lateral bending in the contralateral direction; “ar (ipsi)”: axial rotation in the ipsilateral direction (the same side of the implant of interest); “ar (contra)”: axial rotation in the contralateral direction. Refer to Table 1 for model descriptions and abbreviations.
- Figure 5
Maximal stresses in the left posterior rods in the portion between the L5 and the S1 pedicle screws (PED) predicted for the 5 instrumented configurations (PED, S2AI, PFFI, PFFI-IFSAI, and 2-PFFI). “flex”: flexion; “ext”: extension; “lb (ipsi)”: lateral bending in the ipsilateral direction (the same side of the implant of interest); “lb (contra)”: lateral bending in the contralateral direction; “ar (ipsi)”: axial rotation in the ipsilateral direction (the same side of the implant of interest); “ar (contra)”: axial rotation in the contralateral direction. Refer to Table 1 for model descriptions and abbreviations.
Tables
Model Name Model Description Pedicle screws Pedicle screws, T10 to S1 S2 alar-iliac PED + S2 AI screws Porous fusion/fixation implant PED + porous fusion/fixation implants PFFI-IFSAI PED + porous fusion/fixation implants + triangular titanium implants 2-PFFI PED + stacked porous fusion/fixation implants Configuration Flexion-Extension Lateral Bending Axial Rotation L5-S1 SIJ L5-S1 SIJ L5-S1 SIJ S2AI 0.9 0.6 0.9 0.4 0.8 0.3 PFFI 0.9 0.2 0.9 0.2 0.7 0.1 PFFI-IFSAI 0.9 0.6 0.8 0.4 0.7 0.3 2-PPFI 0.6 0.2 0.4 0.2 0.6 0.1 Abbreviations: PFFI, porous fusion/fixation implant; 2-PFFI, S2AI position PFFI; S2AI, S2 alar-iliac; SIJ, sacroiliac joint.
Note: All values are in degrees (°).
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