Comparison of Radiographic Outcomes for Scoliosis Curves Greater Than or Equal to 100 Degrees: Wires vs Hooks vs Screws
d - Medtronic Sofamor Danek
e - Medtronic Sofamor Danek
Purpose: Spinal fusion in scoliosis curves greater than 100 degrees are challenging surgeries, because of a high rate of complications including pseudarthrosis, instrumentation failure, and neurologic issues. Our purpose was to compare the radiographic outcomes by different techniques and anchors in the surgical treatment of scoliosis greater than 100 degrees.
Methods: 60 patients (21 idiopathic, four congenital and 36 neuromuscular) with greater than 100 degree curves (range; 100-158ยบ) who underwent spinal fusion with different techniques and anchors on the apical levels, were include for analysis. All patients had a minimum 2-year follow-up (mean, 4.2 years; range 2.0-10.5 years) and were classified into Group W (wires, n=25), Group H (hooks, n=18), Group A (anterior vertebral screws, n=6), and Group PS (pedicle screws, n=11), based on the type of apical anchor utilized.
Results: (See Table) There were no statistically significant differences between the groups for gender, age, number of levels fused, and preoperative main curve Cobb angle. Curve flexibility using stress x-rays in the H group was significantly smaller than in the W group (p<0 .05). The PS group showed significantly greater amount of correction than the other groups (p<0.0001) and smaller loss W (p<0.05) at final follow-up. There were four cases pseudarthrosis (W group: 3, H 1), seven implant failure including rod breakage or hook pull-off 5, 2), 12 radiolucency surrounding lowest 9, A 2, 1). Although there neurological complications (3 degraded spinal cord monitoring, 1 failed wake-up test), no permanent deficits.
Conclusions: Apical pedicle screw constructs are able to achieve and maintain better correction without instrumentation failure compared to other instrumentation constructs in scoliosis curves of greater than 100 degrees.
Table: Radiographic data
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Group W (n=25)
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Group H (n=18)
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Group A (n=6)
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Group PS (n=11)
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Significance (ANOVA)
|
|
| Age at Surgery (years) |
13.6 ± 3.9
|
19.4 ± 13.7
|
15.8 ± 1.2
|
15.6 ± 5.5
|
p=0.1691 |
| Surgical Approach |
A/P: 17
|
A/P: 17
|
A/P: 6
|
A/P: 6
|
|
|
Post: 8
|
Post:1
|
Post: 5
|
|
||
| Main Curve Cobb Preoperatively |
113.9 ± 14.7
|
109.4 ±12.7
|
107.2 ± 9.4
|
121.1 ± 19.6*
|
p=0.1402 |
| Stress x-ray Flexibility (%) |
37.5 ± 17.9*
|
23.3 ± 12.0*
|
37.0 ± 16.6
|
31.1 ± 18.3
|
p=0619 |
| Main Curve Cobb Postoperatively |
53.5 ± 18.4*
|
73.3 ± 21.8*†‡
|
42.4 ± 11.6†
|
45.4 ± 23.0‡
|
p‹0.001 |
| Correction Rate (%) |
52.7 ± 16.0*
|
32.9 ± 18.7*†‡
|
60.5 ± 9.7†
|
62.5 ± 17.4‡
|
p‹0.001 |
| Amount of Correction Posteroperative |
58.9 ± 20.6*†
|
35.6 ± 20.8†‡**
|
64.7 ± 10.1‡**
|
75.7 ± 26.0*†‡
|
p‹0.001 |
| Amount of Correction Loss |
8.4 ± 7.6*
|
7.2 ± 11.7
|
4.5 ± 6.8
|
1.9 ± 3.0*
|
p=0.1892 |
| Pelvic Obliquity Preoperatively |
28.7 ± 26.6*†
|
5.2 ± 4.0*
|
20.6 ± 15.8
|
15.4 ± 12.9†
|
p‹0.01 |
| Pelvic Obliquity Postoperatively |
9.8 ± 8.3*
|
4.5 ± 3.7*
|
10.4 ± 6.8
|
6.1 ± 4.1
|
p=0.667 |
| C7 Translation Preoperatively |
137.8 ± 100.6*
|
18.0 ± 12.6*†‡
|
100.0 ± 91.0†
|
89.4 ± 94.6‡
|
p‹0.001 |
| C7 Translation Postoperatively |
66.1 ± 57.1*
|
18.1 ± 11.3*†
|
68.3 ± 67.4†
|
34.8 ± 32.4
|
p‹0.01 |
| Clavicle-Angle Postoperatively |
13.8 ± 9.1*†
|
4.5 ± 3.2*
|
5.6 ± 3.0†
|
9.2 ± 6.8
|
p‹0.005 |
| Clavicle-Angle Postoperatively |
4.7 ± 3.6*
|
4.3 ± 2.4
|
3.6 ± 3.6
|
2.4 ± 1.9*
|
p=0.2191 |
Fisher's PLSD: p‹0.05*†‡