1. Patient demographics (Table 1)
In total, 105 patients underwent ACDF at the authors’ institution. Detailed demographics of 48 out of 105 patients were shown in Table 1. In the matched pair analysis, there was no statistically significant factor in the demographic between the two groups. The total of 105 patients’ ages ranged from 46 to 77 years (average age, 57.9±11.83 years old). The patients were followed for an average of 37.7±10.5 months. The operation level was primarily the C5/6 level (60 cases, 57%), followed by the C4/5 level (23 cases, 22%).
Table 1. Patient demographics
|
ACDF without UPR
(n = 24)
|
ACDF with complete UPR
(n = 24)
|
p-value
|
Sex
|
|
|
|
Female
|
15
|
16
|
|
Male
|
9
|
8
|
0.763
|
Mean age (years)
|
47.9 ± 9.78
|
49.1 ± 9.67
|
0.669
|
BMD (g/cm2)
T-score
|
-0.66 ± 1.21
|
-0.78 ± 0.77
|
0.681
|
BMI (kg/m2)
|
23.5 ± 2.47
|
23.5 ± 2.02
|
0.984
|
DM
|
5
|
6
|
0.731
|
Smoking
|
9
|
6
|
0.351
|
Operation level
|
|
|
|
C2/3
C3/4
|
0
6
|
0
5
|
|
C4/5
C5/6
C6/7
|
15
3
0
|
15
4
0
|
0.999
|
Resection side
|
|
|
|
Unilateral
|
|
20
|
|
Bilateral
|
|
4
|
|
BMD; bone mineral density, BMI; body mass index, DM, diabetes mellitus;
ACDF; anterior cervical discectomy and fusion
UPR; uncinate process removal
*p < 0.05 comparing ACDF without UPR and ACDF with complete UPR
2. Comparison of intraoperative blood loss, operative time, days of hospitalization, and clinical parameters (Table 2)
Intraoperative blood loss, operative time, days of hospitalization, Arm-VAS, Neck-VAS, NDI, and Odom’s criteria of the two groups are shown in Table 2. All of the clinical parameters improved at 2-year follow up (P<0.0001). Regarding Odom’s criteria, most of the surgical results were excellent and good in both groups. Also, there was no complication in either group. There was no statistically significant clinical outcome between the ACDF with UPR and ACDF without UPR groups except for postoperative Arm-VAS.
Table 2. Comparison of intraoperative blood loss, operative time, days of hospitalization, and clinical parameters
|
ACDF without UPR
(n = 24)
Median (Q1-Q3),(min-max) N(%)
|
ACDF with complete UPR
(n = 24)
Median (Q1-Q3),(min-max) N(%)
|
p-value
|
Intraoperative blood loss (ml)
|
60.00(52.50-80.00),(50.00-100.00)
|
77.50(57.50-90.00),(50.00-140.00)
|
0.175
|
Operation time (min)
|
100.00(90.00-120.00),(90.00-150.00)
|
120.00(100.00-130.00),(90.00-155.00)
|
0.086
|
Duration of hospitalization (day)
|
6.00(6.00-7.00),(5.00-9.00)
|
6.00(6.00-7.00),(5.00-9.00)
|
0.866
|
Preoperation
Postoperation
2 years follow-up
|
9.00(8.00-9.00), (7.00-9.00)
4.00(3.00-5.00), (2.00-6.00)
2.00(1.00-2.00), (1.00-3.00)
|
8.50(8.00-9.00), (7.00-9.00)
3.00(2.00-3.50), (2.00-5.00)
2.00(1.00-2.00),(1.00-3.00)
|
0.116
0.003*
0.711
|
Preoperation
Postoperation
2 years follow-up
|
9.00(8.00-9.00), (7.00-9.00)
2.00(1.00-5.00), (1.00-5.00)
1.00(1.00-2.00), (1.00-3.00)
|
9.00(8.00-9.00), (7.00-9.00)
2.00(2.00-3.50), (2.00-5.00)
1.00(1.00-1.00), (1.00-2.00)
|
0.817
0.657
0.281
|
Preoperation
Postoperation
2 years follow-up
|
38.00(37.00-41.50), (35.00-44.00)
24.00(21.00-25.00), (15.00-29.00)
14.00(13.50-16.50), (11.00-19.00)
|
40.50(37.50-42.00), (35.00-44.00)
22.00(19.00-25.00),(15.00-27.00)
13.50(11.00-15.00),(11.00-17.00)
|
0.464
0.514
0.069
|
Excellent
Good
Fair
Poor
|
9
15
0
0
|
9
14
1
0
|
0.999
|
VAS; Visual analog scale, NDI; Neck Disability Index
*p < 0.05 comparing ACDF without UPR and ACDF with UPR
3. Comparison of radiologic parameters (Table 3)
Cervical lordosis, segmental angle, disc height, C2-C7 SVA, St-SVA, T1 slope, SCA, incidence of subsidence, and fusion rate of the two groups are shown in Table 3. All cervical sagittal parameters, including cervical lordosis, segmental angle, disc height, C2-C7 SVA, St-SVA, T1 slope, and SCA, except for preoperative St-SVA, SCA, and disc height of 2 years follow-up, were similar between the ACDF with complete UPR and ACDF without UPR groups. Differences in disc height, C2-C7 SVA, and SCA at 2-year follow up after preoperative examination, however, were statistically significant (p<0.05). Subsidence occurred in 9 patients (ACDF with complete UPR: 8 cases [33%] versus ACDF without UPR: 1 cases [4%]; p < 0.05). Radiological images for representative patients in each group are displayed in Figures 4 and 5. There was no statistical significance because there were only a few cases of removal of uncinate on both sides. However, subsidence occurred more frequently in cases of removal of both sides than in cases of removing only one side.
Table 3. Comparison of radiologic parameters
|
ACDF without UPR
(n = 24)
Mean ± SD, N(%)
|
ACDF with complete UPR
(n = 24)
Mean ± SD, N(%)
|
p-value
|
Preoperation
Postoperation
2 years follow-up
2 years follow-up - Preoperation
|
15.50(9.45-17.60), (3.90-20.80)
15.80(10.25-17.90), (7.70-27.90)
15.95(13.45-24.15), (10.20-28.50)
3.80(0.70-8.50),(-5.70-17.00)
|
14.10(5.45-19.55), (3.90-26.40)
17.25(8.50-19.10), (3.00-27.30)
14.65(11.00-29.70), (1.10-45.50)
5.20(-3.60-15.30),(-12.20-30.00)
|
0.781
0.772
0.877
0.984
|
Preoperation
Postoperation
2 years follow-up
2 years follow-up - Preoperation
|
5.45(4.60-5.95), (1.80-7.10)
5.85(2.90-7.45), (0.50-14.40)
5.90(5.10-7.25), (1.20-9.60)
0.70(-0.75-2.90), (-4.80-5.30)
|
4.95(4.00-5.50), (1.30-7.10)
5.70(3.45-7.55), (1.00-14.40)
5.20(3.75-6.10), (0.90-10.00)
0.50(-1.60-2.30), (-4.80-6.90)
|
0.215
0.918
0.207
0.643
|
Preoperation
Postoperation
2 years follow-up
2 years follow-up – Preoperation
|
5.60(5.15-6.18), (4.23-7.90)
7.16(6.46-7.90), (5.84-8.91)
6.22(5.41-6.58), (4.82-13.12)
0.08(-0.52-2.02), (-1.42-6.95)
|
5.96(5.58-6.26), (5.18-6.97)
7.53(7.27-7.84), (6.52-8.91)
5.19(5.15-5.55), (5.01-5.82)
-0.44(-1.15--0.19), (-1.78-0.45)
|
0.173
0.117
<0.001*
0.007*
|
Preoperation
Postoperation
2 years follow-up
2 years follow-up - Preoperation
|
20.05(15.39-26.31), (12.46-30.53)
19.33(13.92-26.13), (9.77-29.04)
15.78(12.36-21.51), (10.62-30.84)
-3.98(-5.80--2.84), (-9.62-7.01)
|
17.06(15.15-24.72), (6.97-28.53)
18.58(13.25-29.88), (6.72-39.25)
17.28(11.18-29.57), (4.42-41.93)
-0.26(-4.15-5.88), (-5.32-15.96)
|
0.261
0.877
0.703
0.005*
|
Preoperation
Postoperation
2 years follow-up
2 years follow-up - Preoperation
|
30.77(24.05-35.06), (15.71-42.98)
27.65(17.49-28.63), (10.59-52.27)
24.53(11.82-32.77), (9.37-48.84)
-1.30(-3.00-1.25), (-14.90-2.90)
|
25.68(20.72-29.36), (13.25-55.43)
28.94(17.12-30.42), (4.40-61.23)
28.56(11.53-41.36), (4.74-77.58)
0.50(-0.70-2.75), (-15.40-7.10)
|
0.018*
0.414
0.496
0.066
|
Preoperation
Postoperation
Last follow-up
Last follow-up - Preoperation
|
25.15(20.25-27.90), (12.00-31.60)
24.85(17.10-28.10), (13.60-32.80)
23.50(17.60-27.00), (12.00-33.20)
-1.30(-3.00-1.25), (-14.90-2.90)
|
24.10(22.00-25.90), (11.90-44.00)
25.40(20.50-27.55), (14.80-32.50)
25.80(20.75-28.00), (15.40-49.20)
0.50(-0.70-2.75), (-15.40-7.10)
|
0.687
0.599
0.327
0.066
|
Preoperation
Postoperation
2 years follow-up
2 years follow-up - Preoperation
|
104.65(101.20-108.65), (89.90-115.90)
104.75(100.90-108.45), (94.60-117.00)
105.80(100.60-111.60), (92.80-115.50)
3.65(-4.50-8.35), (-13.30-10.70)
|
111.05(107.85-114.70), (101.20-120.00)
105.90(103.65-111.45), (95.50-113.60)
105.80(99.10-107.30), (87.30-121.40)
-8.15(-15.15-2.70), (-20.10-9.80)
|
<0.001*
0.397
0.634
0.004*
|
Subsidence
|
1 (4%)
|
8 (33%)
|
0.023*
|
Fusion
|
22 (92%)
|
22 (92%)
|
0.999
|
SVA; sagittal vertical axis, St-SVA; sellar turcica–sagittal vertical axis,
SCA; spinocranial angle
* Statistically significant
4. Binary multiple logistic regression of the five measurements as significant parameters on subsidence (Table 4)
Radiologic factors that may potentially associate with subsidence were analyzed using binary multiple logistic regression test. The results are shown in Table 4. As an association factor of subsidence, preoperative SCA values were significant (P<0.05). In opposition to our hypothesis, complete UPR was not a significant factor affecting subsidence.
Table 4. Binary multiple analysis of the five measurements as significant parameters on subsidence
Factor
|
Odds Ratio
|
95% CI
|
p-value
|
Preoperative C2–C7 SVA
|
1.034
|
0.896 – 1.192
|
0.651
|
Preoperative St-SVA
|
0.946
|
0.863 – 1.037
|
0.238
|
Preoperative SCA
|
1.237
|
1.074 – 1.425
|
0.003*
|
Preoperative CL
|
0.950
|
0.817 – 1.104
|
0.503
|
Preoperative T1-slope
|
0.998
|
0.870 – 1.145
|
0.978
|
SVA; sagittal vertical axis, St-SVA; sellar turcica–sagittal vertical axis,
SCA; spinocranial angle, CL; cervical lordosis, CI: confidence interval
* Statistically significant