Table 2.
Comparison of patient demographic data in the MIS and open cohorts
| Variable | Number of studies | MIS cohort | Open cohort | p value |
|---|---|---|---|---|
| Number of patients | 26 | 856 | 806 | |
| Mean age (years) | 15 | 55.32 | 56.71 | 0.07† |
| Sex (% male) | 22 | 41 | 44 | 0.12‡ |
| Surgical level (%)* | 24 | 0.44§ | ||
| 1-level | 92 | 90 | ||
| 2-level | 8 | 9 | ||
| Diagnosis (%) | 14 | 0.25§ | ||
| Spinal stenosis | 20 | 17 | ||
| Degenerative spondylolisthesis | 40 | 42 | ||
| Isthmic spondylolisthesis | 17 | 17 | ||
| Degenerative disc disease | 15 | 13 | ||
| Other | 7 | 11 |
* One study had a separate category for 3+ level surgeries; this subsample was omitted; †independent two-sample t-test; ‡two-proportion z-test; §chi-square test of independence; MIS = minimally invasive surgery.