Article Figures & Data
Figures
- Figure 1
Profile of the mean reduction from baseline and 95% CIs for visual analog scale (VAS) back and leg pain scores. All improvements from baseline were statistically significant (P < 0.001).
- Figure 2
Profile of the mean reduction from baseline and 95% CIs for Oswestry Disability Index (ODI) and Roland-Morris Disability Questionnaire (RMDQ) disability scores. All improvements from baseline were statistically significant (P < 0.001).
- Figure 3
X-ray images of a Charité Artificial Disc at 183 mo after surgery: (a) flexion, (b) extension, (c) anteroposterior, and (d) lateral.
- Figure 4
Patient satisfaction levels over the duration of postsurgery follow-up (N = 211).
Tables
Characteristic n (%) Gender Female 93 (44.1) Male 118 (55.9) Age at time of surgery (y), mean (SD) 42.2 (11.1) Age group <35 y 47 (22.3) 35–45 y 83 (39.3) >45 y 81 (38.4) Level L4-L5 51 (24.2) L5-S1 160 (75.8) Pain, median (IQR) VAS-backa 75.0 (55.0–89.0) VAS-leg 60.0 (17.0–83.0) Disability, median (IQR) ODIb 46.0 (34.0–56.0) RMDQc 16.0 (12.0–19.0) Abbreviations: IQR, interquartile range; ODI, Oswestry Disability Index; RMDQ, Roland-Morris Disability Questionnaire; VAS, visual analog scale.
Note: Data are presented as n (%) unless otherwise indicated.
↵a The VAS is scored on a 0 (no pain) to 100 (worst pain) scale.
↵b The ODI is scored on a 0 (none) to 100 (worst) disability scale.
↵c The RMDQ is scored on a 0 (none) to 24 (worst) disability scale.
Time After Surgery VAS-Back VAS-Leg n Median IQR n Median IQR 0 (baseline) 211 75.0 55.0–89.0 211 60.0 17.0–83.0 6 mo 197 9.0 2.0–20.0 193 1.0 0.0–13.0 1 y 196 5.0 0.0–20.0 192 1.0 0.0–10.0 2 y 187 3.0 0.0–17.0 188 1.0 0.0–11.0 4 y 184 5.5 0.0–22.0 183 1.0 0.0–14.5 5 y 158 6.0 0.0–19.8 158 1.0 0.0–7.0 8 y 96 6.5 1.0–20.0 97 2.0 0.0–7.0 10 y 62 5.0 1.0–21.0 62 1.0 0.0–4.8 13 y 24 12.0 1.0–45.3 24 3.5 0.8–19.0 Time After Surgery ODI RMDQ n Median IQR n Median IQR 0 (baseline) 211 46.0 34.0–56.0 211 16.0 12.0–19.0 6 mo 198 6.0 0.0–18.0 193 1.0 0.0–3.0 1 y 197 4.0 0.0–14.0 195 0.0 0.0–2.0 2 y 188 2.0 0.0–14.0 186 0.0 0.0–2.0 4 y 182 6.0 0.0–14.0 182 0.0 0.0–3.0 5 y 157 4.0 0.0–14.0 157 0.0 0.0–4.0 8 y 97 4.0 0.0–14.0 95 0.0 0.0–3.0 10 y 62 4.0 0.0–13.5 62 0.0 0.0–3.0 13 y 24 4.0 0.0–19.0 23 0.0 0.0–4.5 Abbreviations: IQR, interquartile range; ODI, Oswestry Disability Index; RMDQ, Roland-Morris Disability Questionnaire; VAS, visual analog scale.
- Table 3
Estimates of the fixed effects in the mixed-effects regression modeling of pain and disability change scores over 13 y.
Parameter Coefficient β 95% CI P Value VAS-B Intercept 60.3 (58.3, 62.3) <0.001b Baseline score (centered on 75) 0.9 (0.9, 1.0) <0.001b Time, y −0.6 (−1.0, −0.2) 0.002b VAS-L Intercept 53.1 (49.0, 57.3) <0.001b Baseline score (centered on 60) 0.9 (0.9, 1.0) <0.001b Time, y −0.2 (−0.5, 0.1) 0.27 Age groupa coded 1 (35–45 y) −3.1 (−8.3, 2.1) 0.24 Age groupa coded 2 (>45 y) −7.2 (−12.3, −2.0) 0.007b ODI Intercept 35.0 (33.5, 36.5) <0.001b Baseline score (centered on 46) 0.9 (0.8, 1.0) <0.001b Time, y 0.1 (−0.1, 0.4) 0.22 RMDQ Intercept 13.7 (13.2, 14.1) <0.001b Baseline score (centered on 16) 1.0 (0.9, 1.1) <0.001b Time, y −0.03 (−0.11, 0.05) 0.45 Abbreviations: ODI, Oswestry Disability Index; RMDQ, Roland-Morris Disability Questionnaire; VAS-B, visual analog scale for back pain; VAS-L, visual analog scale for leg pain.
↵a Reference age group coded 0: <35 y.
↵b Statistically significant P < 0.0125. A negative coefficient signifies a decrease in improvement. The intercept coefficient represents the mean change score at year 1 for patients with median baseline for VAS-B, ODI, and RMDQ and for the <35 y age group for VAS-L.
Time After Surgery (in mo) Total n Excellent/Good,
n (%)3 184 171 (92.9) 6 180 169 (93.9) 12 178 164 (92.1) 24 179 167 (93.3) 36 174 161 (92.5) 48 181 165 (91.2) 60 157 146 (93.0) 72 138 129 (93.5) 84 121 115 (95.0) 96 92 89 (96.7) 108 81 75 (92.6) 120 61 59 (96.7)
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