Characteristics of studies examining the difference of refracture between sandwich vertebra and nonsandwich vertebra.
| Study | Study Type | Participants, n | Mean Age, y | Gender, Male/Female | Mean Follow-Up, mo |
| Bo et al (2022)7 | Retrospective | 225 | 73.8 (62.8–84.7) | 79/146 | 28.55 (15.6–41.5) |
| Han et al (2018)8 | Retrospective | 132 | 76.6 (68.4–84.8) | 15/117 | 15.9 (6.2–24.62) |
| Chiu et al (2020)12 | Retrospective | 1321 | 77.8 (70.1–85.5) | NM | 39.6 (24.0–61.0) |
| Hierholzer et al (2008)13 | Retrospective | 316 | 73.0 (-) | 257/59 | 8.0 (6.0–56.0) |
| Jiang et al (2017)14 | Case-control | 111 | 68.0 (46.0–90.0) | 17/94 | 26.3 (17.6–35.0) |
| Liu et al (2021)15 | Retrospective | 1228 | 73.9 (53.0–89 .0) | 27/88 | 39.4 (12.6–71.6) |
| Pitton et al (2007)16 | Prospective | 191 | 70.7 (61.0–80.4) | 61/130 | 19.7 (7.0–32.4) |
| Zeng et al (2018)17 | Prospective | 349 | 60.0 (-) | NM | 40.0 (12.0–60.0) |
| Zhang et al (2021)18 | Retrospective | 179 | 74.4 (62.8–85.5) | NM | 21.5 (15.7–27.2) |
Abbreviation: NM, not mentioned.