## 3 Results
\begin{table}
\begin{tabular}{l c c c c c} \hline
**Variable** & \(n\) & **Absent** & **Mean (\(\pm\)SD)** & **Median (IQR)** & **Min-Max** \\ \hline
**Outpatient follow-up time** & 330 & 0 & 1062.50 (\(\pm\)338.55) & 934.50 (809.00–1228.50) & 728.00–2346.00 \\ Number of instrumented levels & 330 & 0 & 12.68 (\(\pm\)2.76) & 12.00 (11.00–15.75) & 6.00–22.00 \\ Curve 1, proximal thoracic, preoperative & 330 & 0 & 1.85 (\(\pm\)9.06) & 0.00 (0.00–0.00) & 0.00–76.00 \\ Without traction & 330 & 0 & 1.34 (\(\pm\)7.13) & 0.00 (0.00–0.00) & 0.00–76.00 \\ Curve 1, postoperative & 330 & 0 & 0.71 (\(\pm\)3.83) & 0.00 (0.00–0.00) & 0.00–35.00 \\ Curve 2, thoracic, preoperative without traction & 330 & 0 & 26.81 (\(\pm\)26.32) & 32.00 (0.00–49.00) & 0.00–90.00 \\ Curve 2, preoperative with traction & 330 & 0 & 16.80 (\(\pm\)18.72) & 12.00 (0.00–31.00) & 0.00–78.00 \\ Curve 2, postoperative & 330 & 0 & 9.03 (\(\pm\)12.92) & 2.00 (0.00–14.00) & 0.00–74.00 \\ Curve 3, thoracolumbar or lumbar, preoperative & 330 & 0 & 36.60 (\(\pm\)29.92) & 42.00 (0.00–57.00) & 0.00–144.00 \\ without traction & 330 & 0 & 20.90 (\(\pm\)22.30) & 15.00 (0.00–35.00) & 0.00–114.00 \\ Curve 3, postoperative & 330 & 0 & 12.78 (\(\pm\)17.48) & 5.00 (0.00–19.00) & 0.00–90.00 \\ Main curve & 330 & 0 & 54.44 (\(\pm\)16.52) & 50.50 (43.00–63.00) & 15.00–144.00 \\ Sum of secondary curves & 330 & 0 & 10.82 (\(\pm\)20.80) & 0.00 (0.00–0.00) & 0.00–108.00 \\ Main curve flexibility, degrees & 330 & 0 & 21.73 (\(\pm\)17.11) & 21.01 (0.30–29.00) & 0.00–56.00 \\ Secondary curve flexibility, degrees & 330 & 0 & 4.49 (\(\pm\)9.43) & 0.00 (0.00–0.00) & 0.00–41.00 \\ Main curve flexibility, percentage & 330 & 0 & 0.42 (\(\pm\)0.24) & 0.40 (0.25–0.58) & 0.00–1.00 \\ Secondary curve flexibility, percentage & 330 & 0 & 0.10 (\(\pm\)0.21) & 0.00 (0.00–0.00) & 0.00–0.95 \\ Main curve (postoperative) & 330 & 0 & 18.08 (\(\pm\)17.01) & 13.00 (6.00–24.00) & 0.00–90.00 \\ Sum of secondary curves (postoperative) & 330 & 0 & 4.44 (\(\pm\)10.58) & 0.00 (0.00–0.00) & 0.00–67.00 \\ Main curve correction, degrees & 330 & 0 & 36.36 (\(\pm\)13.20) & 36.00 (29.00–43.00) & \(-\)17.00–76.00 \\ Secondary curve correction, degrees & 330 & 0 & 6.38 (\(\pm\)13.16) & 0.00 (0.00–0.00) & \(-\)4.00–75.00 \\ Main curve correction, percentage & 330 & 0 & 0.70 (\(\pm\)0.23) & 0.74 (0.58–0.86) & \(-\)0.52–10.00 \\ Secondary curve correction, percentage & 80 & 250 & 0.61 (\(\pm\)0.27) & 0.58 (0.46–0.82) & \(-\)0.09–1.00 \\ Time to surgery for complications, days & 21 & 309 & 514.86 (\(\pm\)386.22) & 399.00 (272.00–714.00) & 38.00–1435.00 \\ Revision surgeries & 9 & 321 & 1.22 (\(\pm\)0.44) & 1.00 (1.00–1.00) & 1.00–20.00 \\ \hline \end{tabular}
\begin{tabular}{l c c c} \hline  & \multicolumn{3}{c}{**(a)**} \\ \hline \multicolumn{3}{c}{**Material Failure**} \\ \hline  & **Yes** & **No** & **Total** \\ \hline  & \(n\) & **\% (95\% CI)** & \(n\) & **\% (95\% CI)** & \(n\) \\ \hline Main curve flexibility & & & \(p=0.26\) & \\ Flexible & 8 & 4.76 (2.38–8.04) & 160 & 95.24 (92.86–98.51) & 168 \\ Nonflexible & 13 & 8.02 (4.32–11.89) & 149 & 91.98 (88.27–95.84) & 162 \\ Secondary curve flexibility & & & \(p=0.31\) & \\ Flexible & 4 & 9.76 (2.44–17.70) & 37 & 90.24 (82.93–98.19) & 41 \\ Nonflexible & 17 & 5.88 (3.46–8.39) & 272 & 94.12 (91.70–96.63) & 289 \\ Total & 21 & 309 & & 330 \\ \hline \multicolumn{3}{c}{**(b)**} \\ \hline Flexibility and material failure & & & \\ Main curve & & Secondary curves & \\ Degrees–\(p\)-value & 0.6 & 0.6 & 0.7 \\ Percentage–\(p\)-value & 0.3 & & 0.7 \\ Method & Mann–Whitney & & \\ \hline \end{tabular}
\end{table} 
Table 2: Descriptive statistics of quantitative variables.