PMC8192795_01
Spinal alignment evaluation. Sagittal spino-pelvic parameters (A-C) for the assessment of the alignment [A-C adopted from Lafage et al. ]: pelvic parameters measured were PI, PT, and SS. Regional spinal parameters included PI-LL mismatch, LL, and TK. Global alignment was assessed linearly by SVA and the angular measurements of T1SPI, T9SPI, and TPA. Cervical parameters were composed of T1 slope, C2-C7 cervical lordosis, and C2-C7 SVA. (D) For the GAP score L4-S1 lordosis L(L4-S1) and the global tilt (GT) were defined. (E) Coronal alignment is assessed by measuring the distance between the center of the C7 vertebral body and the CSVL.
fsurg-08-662919-g0001.jpg
PMC8192795_02_fsurg-08-662919-g0001.jpg
F1
Definition of virtual 3D geometry from CT scan. During the segmentation process the bone volume is first separated from the surrounding soft tissue by thresholding of the greyscale levels of the CT images. The resulting mask (green) voxels represent the 3D volume of the L1-S1 spine segment. Then, from the mask, a triangulated surface mesh is generated in STL format. The STL file serves as an input for 3D printing, with FDM technology. The virtual patient-specific geometry can be edited in CAD software in order to perform virtual surgical intervention (L4 PSO). The virtual geometries are then integrated in the clinical communication as a 3DPDF document.
fsurg-08-662919-g0002.jpg
PMC8192795_02_fsurg-08-662919-g0002.jpg
F2
To better understand the complex anatomical condition at the lower lumbar level, especially in the neuro foraminal and central spinal canal area, patient-specific virtual and physical models were created based on the pre-op CT (Figure 2). The thresholding algorithm and manual segmentation tools (erase, paint, fill etc.) were used in 3D Slicer 4.1.1 free software (Brigham and Women's Hospital, Boston, MA, USA), Figure 2. To evaluate the accuracy of the segmentation process, the Dice Similarity
PMC8192795_02
Spinal alignment evaluation. Sagittal spino-pelvic parameters (A-C) for the assessment of the alignment [A-C adopted from Lafage et al. ]: pelvic parameters measured were PI, PT, and SS. Regional spinal parameters included PI-LL mismatch, LL, and TK. Global alignment was assessed linearly by SVA and the angular measurements of T1SPI, T9SPI, and TPA. Cervical parameters were composed of T1 slope, C2-C7 cervical lordosis, and C2-C7 SVA. (D) For the GAP score L4-S1 lordosis L(L4-S1) and the global tilt (GT) were defined. (E) Coronal alignment is assessed by measuring the distance between the center of the C7 vertebral body and the CSVL.
fsurg-08-662919-g0001.jpg
PMC8192795_02_fsurg-08-662919-g0001.jpg
F1
Definition of virtual 3D geometry from CT scan. During the segmentation process the bone volume is first separated from the surrounding soft tissue by thresholding of the greyscale levels of the CT images. The resulting mask (green) voxels represent the 3D volume of the L1-S1 spine segment. Then, from the mask, a triangulated surface mesh is generated in STL format. The STL file serves as an input for 3D printing, with FDM technology. The virtual patient-specific geometry can be edited in CAD software in order to perform virtual surgical intervention (L4 PSO). The virtual geometries are then integrated in the clinical communication as a 3DPDF document.
fsurg-08-662919-g0002.jpg
PMC8192795_02_fsurg-08-662919-g0002.jpg
F2
To better understand the complex anatomical condition at the lower lumbar level, especially in the neuro foraminal and central spinal canal area, patient-specific virtual and physical models were created based on the pre-op CT (Figure 2). The thresholding algorithm and manual segmentation tools (erase, paint, fill etc.) were used in 3D Slicer 4.1.1 free software (Brigham and Women's Hospital, Boston, MA, USA), Figure 2. To evaluate the accuracy of the segmentation process, the Dice Similarity
Preoperative (A,B) and postoperative (C,D) standing X-rays for sagittal (A,C) and coronal (B,D) spinal alignment evaluation, using the Surgimap software sagittal alignment tools. In the sagittal plane, the SVA was reduced by 7.4 cm compared to the preoperative X-rays due to the Th9-Ileum fixation, correction with the L3-L4 intervertebral fusion (TLIF) and the 3-column osteotomy at the L4 level. The coronal alignment was corrected by reducing the distance between C7 to CSVL from 4.8 cm pre-op (B) to 0.5 cm post-op (D).
fsurg-08-662919-g0003.jpg
PMC8192795_02_fsurg-08-662919-g0003.jpg
F3