Characteristics of patient demographics included in meta-analyses.
| Study | No. of Patients | Mean Age, y | Level(s) | Posterior Instrumentation | ||
| Outpatient | Inpatient | Outpatient | Inpatient | |||
| Jones11 | 149 | 3579 | NA | NA | 1 | N |
| Snowden12 | 29 | 33 | 44.2 | 51.6 | 1 | Y |
| Cuellar13 | 124 | 102 | 43.6 | 47.6 | 1–3 | N |
| Kamalapathy14 | 1768 | 8840 | NA | NA | 1 | NA |
Abbreviations: N, no; NA, not available; Y, yes.