Figure 1.
Fabrication procedure for the patient-specific Nuss bar.
Figure 1.
Fabrication procedure for the patient-specific Nuss bar.
Figure 2.
Fabrication procedure for the 3D chest wall model for a PE patient: (a) Step 1; (b) Steps 2 and 3; (c) Step 4.
Figure 2.
Fabrication procedure for the 3D chest wall model for a PE patient: (a) Step 1; (b) Steps 2 and 3; (c) Step 4.
Figure 3.
Illustration of pectus indices calculated from the computed tomography (CT) axial image with greatest sternum depression: (a) description of the Haller index; (b) measurement of the Haller index before and after the Nuss operation.
Figure 3.
Illustration of pectus indices calculated from the computed tomography (CT) axial image with greatest sternum depression: (a) description of the Haller index; (b) measurement of the Haller index before and after the Nuss operation.
Figure 4.
Virtual surgery scenario for insertion point and shape design of Nuss bar: (a) Nuss bar is inserted at A, B, and C points from 3D chest wall model; (b) CT axial images with insertion points A, B, and C.
Figure 4.
Virtual surgery scenario for insertion point and shape design of Nuss bar: (a) Nuss bar is inserted at A, B, and C points from 3D chest wall model; (b) CT axial images with insertion points A, B, and C.
Figure 5.
Illustrations of corrected sternum after Nuss bar insertion. The same shape of the Nuss bar was located on the CT axial image with insertion points.
Figure 5.
Illustrations of corrected sternum after Nuss bar insertion. The same shape of the Nuss bar was located on the CT axial image with insertion points.
Figure 6.
Establishment of CNC bending machine. In the figure, components of the CNC bending machine are (1) main body, (2) control cabinet, and (3) air pump.
Figure 6.
Establishment of CNC bending machine. In the figure, components of the CNC bending machine are (1) main body, (2) control cabinet, and (3) air pump.
Figure 7.
Images of feeding and rotation parts of the CNC bending machine: (a) image of the feeding and rotation assembly, composed of the (1) rotation module, (2) set of clamps, (3) feeding module, and (4) Nuss bar jig; (b) image of the customized jig tool for Nuss bar processing.
Figure 7.
Images of feeding and rotation parts of the CNC bending machine: (a) image of the feeding and rotation assembly, composed of the (1) rotation module, (2) set of clamps, (3) feeding module, and (4) Nuss bar jig; (b) image of the customized jig tool for Nuss bar processing.
Figure 8.
Left and front view of Nuss bar jig design. Designed jig is holding metal bar during the production process of patient-specific Nuss bar by CNC bending machine.
Figure 8.
Left and front view of Nuss bar jig design. Designed jig is holding metal bar during the production process of patient-specific Nuss bar by CNC bending machine.
Figure 9.
Bending unit for Nuss bar manufacturing by CNC bending machine. (a) This picture shows the maximum range of movement of the bending tool. (b) This picture shows the Nuss bar (straight) being inserted into the machine; the Nuss bar makes a 90-degree angle with the bending unit.
Figure 9.
Bending unit for Nuss bar manufacturing by CNC bending machine. (a) This picture shows the maximum range of movement of the bending tool. (b) This picture shows the Nuss bar (straight) being inserted into the machine; the Nuss bar makes a 90-degree angle with the bending unit.
Figure 10.
Minimum AP distance before and after the Nuss procedure. Values of minimum AP distance with Nuss bar insertion points are shown by histogram.
Figure 10.
Minimum AP distance before and after the Nuss procedure. Values of minimum AP distance with Nuss bar insertion points are shown by histogram.
Figure 11.
Haller index before and after the Nuss procedure. The values of the Haller index with insertion points of the Nuss bar are shown in the histogram.
Figure 11.
Haller index before and after the Nuss procedure. The values of the Haller index with insertion points of the Nuss bar are shown in the histogram.
Figure 12.
CT images of asymmetric patients. (a) and (b) are CT images taken before the Nuss operation; (a’) and (b’) are images taken after the Nuss operation. Yellow lines in (a’) and (b’) show the patient-specific Nuss bar.
Figure 12.
CT images of asymmetric patients. (a) and (b) are CT images taken before the Nuss operation; (a’) and (b’) are images taken after the Nuss operation. Yellow lines in (a’) and (b’) show the patient-specific Nuss bar.
Figure 13.
Three components of the Nuss bar. Arc and transition were used to draw the test sample for the bending test.
Figure 13.
Three components of the Nuss bar. Arc and transition were used to draw the test sample for the bending test.
Figure 14.
Bending Springback Calculator from CUSTOMPART.NET [
23]; springback factor (
Ks), final bend radius (
FR), and final bend angle are changed by input values which are sheet thickness (
Mt), K-factor, yield strength, elasticity, initial bend angle, and initial bend radius (
IR).
Figure 14.
Bending Springback Calculator from CUSTOMPART.NET [
23]; springback factor (
Ks), final bend radius (
FR), and final bend angle are changed by input values which are sheet thickness (
Mt), K-factor, yield strength, elasticity, initial bend angle, and initial bend radius (
IR).
Figure 15.
Designs of test sample: (a) central arc design with measuring point of maximum width and height; (b) transition Nuss bar design with measuring points.
Figure 15.
Designs of test sample: (a) central arc design with measuring point of maximum width and height; (b) transition Nuss bar design with measuring points.
Figure 16.
This histogram shows the dimensions of the Nuss bar. The maximum width of SUS and Ti-Gr5 central arc Nuss bars was measured and compared with original width.
Figure 16.
This histogram shows the dimensions of the Nuss bar. The maximum width of SUS and Ti-Gr5 central arc Nuss bars was measured and compared with original width.
Figure 17.
Results for the dimension accuracy of the central arc Nuss bar. This histogram shows the maximum height of the central arc Nuss bars (SUS and Ti-Gr5). Heights were measured and compared with original height.
Figure 17.
Results for the dimension accuracy of the central arc Nuss bar. This histogram shows the maximum height of the central arc Nuss bars (SUS and Ti-Gr5). Heights were measured and compared with original height.
Figure 18.
Results for the dimension accuracy of the SUS and Ti-Gr5 transition Nuss bar. This histogram shows the maximum width of the SUS and Ti-Gr5 transition Nuss bars. Widths were measured and compared with original width.
Figure 18.
Results for the dimension accuracy of the SUS and Ti-Gr5 transition Nuss bar. This histogram shows the maximum width of the SUS and Ti-Gr5 transition Nuss bars. Widths were measured and compared with original width.
Figure 19.
Results for the dimension accuracy of the SUS and Ti-Gr5 transition Nuss bar. This histogram shows the maximum height of the SUS and Ti-Gr5 transition Nuss bars. Heights were measured and compared with original height.
Figure 19.
Results for the dimension accuracy of the SUS and Ti-Gr5 transition Nuss bar. This histogram shows the maximum height of the SUS and Ti-Gr5 transition Nuss bars. Heights were measured and compared with original height.
Figure 20.
Three types of patient-specific Nuss bar drawings and products with Ti-Gr5: (a) symmetric Nuss bar design and (a’) symmetric Nuss bar product for Patient No. 1; (b) eccentric Nuss bar design, which was fitted for an asymmetric chest wall patient (Patient No. 2), and (b’) eccentric Nuss bar product; (c) unbalanced Nuss bar design, which was fitted for an asymmetric chest wall patient (Patient No. 3), And (c’) unbalanced Nuss bar product.
Figure 20.
Three types of patient-specific Nuss bar drawings and products with Ti-Gr5: (a) symmetric Nuss bar design and (a’) symmetric Nuss bar product for Patient No. 1; (b) eccentric Nuss bar design, which was fitted for an asymmetric chest wall patient (Patient No. 2), and (b’) eccentric Nuss bar product; (c) unbalanced Nuss bar design, which was fitted for an asymmetric chest wall patient (Patient No. 3), And (c’) unbalanced Nuss bar product.
Figure 21.
Dimension accuracy histogram of patient-specific Nuss bar: (a) maximum width of patient-specific Nuss bars was measured after Nuss bar processing and compared with original value; (b) maximum height of patient-specific Nuss bars was measured and compared with original data.
Figure 21.
Dimension accuracy histogram of patient-specific Nuss bar: (a) maximum width of patient-specific Nuss bars was measured after Nuss bar processing and compared with original value; (b) maximum height of patient-specific Nuss bars was measured and compared with original data.
Table 1.
Classification of the Haller index.
Table 1.
Classification of the Haller index.
Degree of Pectus Excavatum | Range of Haller Index |
---|
Normal chest | <2.0 |
Mild excavatum | 2.0–3.2 |
Moderate excavatum | 3.2–3.5 |
Severe excavatum | >3.5 |
Table 2.
Specification of the CNC bending machine.
Table 2.
Specification of the CNC bending machine.
Average Power Consumption | Electrical Requirement | Installed Power | Air Requirement |
---|
1.9 KW/h | 230 Volts/single-phase/50–60 Hz | 5 kVA | Dry air 100 psi (min. 80 psi) |
Table 3.
Operating parameter values to operate the CNC bending machine for the Nuss bar.
Table 3.
Operating parameter values to operate the CNC bending machine for the Nuss bar.
Index | Description | Value |
---|
0 | Default Units | 0.0000 |
1 | Stop Machine if done | 0.0000 |
6 | Return Bender Speed | 100.0000 |
7 | Delay at the end of program | 0.0000 |
12 | Cut at the end of program | 3.0000 |
16 | Negative Z-axis limit | −200.0000 |
17 | Positive Z-axis limit | 200.0000 |
18 | Initial Feeder position * | 756.750 |
19 | Initial Bender position | 0.0000 |
20 | Output ON Delay | 80.0000 |
21 | Output OFF Delay | 80.0000 |
23 | Feeder Clamp move to grip | 0.0000 |
24 | Arm Collision detection Rotation Default | 5.0000 |
Table 4.
Tool geometry setting values for increasing accuracy of bending result.
Table 4.
Tool geometry setting values for increasing accuracy of bending result.
Index | Description | Value |
---|
0 | Inner bending roller diameter (mm) | 19.050 |
1 | Outer bending roller diameter (mm) | 19.050 |
3 | Upper Roller Center to X (mm) | 27.305 |
10 | Tool type (#) | 5 (=Mandrel cluster) |
11 | Tool Cluster Diameter | 75.001 |
Table 5.
Haller index values before and after the Nuss procedure in Patient No. 1.
Table 5.
Haller index values before and after the Nuss procedure in Patient No. 1.
Point | A (mm): Pre-Op. | A’ (mm): Post-Op. | B (mm): Pre-Op. | C (mm): Post-Op. | HI: Pre-Op. | ICI: Post-Op. |
---|
A | 217.86 | 206.97 | 73.01 | 101.11 | 2.98 | 2.05 |
B | 215.22 | 204.46 | 68.61 | 103.49 | 3.14 | 1.98 |
C | 217.57 | 206.70 | 73.30 | 104.15 | 2.97 | 1.98 |
Table 6.
Haller index before and after the Nuss procedure in Patients Nos. 2 and 3.
Table 6.
Haller index before and after the Nuss procedure in Patients Nos. 2 and 3.
Type | A (mm): Pre-Op. | A’ (mm): Post-Op. | C (mm): Pre-Op. | C’ (mm): Post-Op. | HI: Pre-Op. | ICI: Post-Op. |
---|
Eccentric (Patient No. 2) | 197.2 | 187.34 | 60.4 | 84.4 | 3.26 | 2.22 |
Unbalanced (Patient No. 3) | 246.0 | 233.7 | 72.6 | 98.6 | 3.39 | 2.37 |
Table 7.
Data of springback factors.
Table 7.
Data of springback factors.
Material | Sheet Thickness (mm) | K-Factor | Yield Strength (psi *) | Elastic Modulus (psi) * | Initial Bend Radius (mm) | Initial Bend Angle (°) |
---|
Ti-Gr5 | 3 | 0.33 | 140,000 | 16,500 | Up to transition values |
SUS | 3 | 0.33 | 116,000 | 28,000 |
Table 8.
Data table for patient-specific Nuss bar dimension accuracy.
Table 8.
Data table for patient-specific Nuss bar dimension accuracy.
| Symmetric | Eccentric | Unbalanced |
---|
SUS | Ti-Gr5 | SUS | Ti-Gr5 | SUS | Ti-Gr5 |
---|
Drawing (mm) | Width (A) | 298.1 | 304.2 | 297.8 |
Height (B) | 86.3 | 84.4 | 78.6 |
Specimen 1 (mm) | Width (A) | 297.5 | 298 | 303 | 305 | 299 | 297 |
Height (B) | 85 | 86 | 86 | 85 | 82 | 80.5 |
Specimen 2 (mm) | Width (A) | 298.5 | 298 | 302 | 304 | 296 | 298 |
Height (B) | 86 | 85 | 86 | 86 | 82 | 79.5 |
Specimen 3 (mm) | Width (A) | 300 | 300 | 303 | 302 | 297 | 299 |
Height (B) | 86 | 85 | 87 | 85 | 82.5 | 81.5 |