Demographic characteristics of patients undergoing biportal endoscopic lumbar surgery.
| Variable | Outpatient | Inpatient | Total | P Valuea |
| (n = 58) | (n = 26) | (N = 84) | ||
| Female, n (%) | 14 (24%) | 11 (42%) | 25 (30%) | 0.15 |
| Age, y | ||||
| Mean (SD) | 53.9 (15.5) | 73.6 (8.2) | 60.0 (16.4) | <0.0001 |
| Median (range) | 57.5 (24–81) | 71.5 (57–89) | 65 (24–89) | |
| Body mass index, kg/m2 | ||||
| Mean (SD) | 27.6 (5.0) | 27.7 (3.6) | 27.6 (4.6) | 0.92 |
| Median (range) | 26.7 (19.8–38.5) | 27.4 (22.0–36.9) | 27 (19.8–38.5) | |
| ASA classification >2 | ||||
| n (%) | 13 (22%) | 19 (73%) | 2.3 (0.6) | <0.0001 |
| Median (range) | 2 (1–3) | 3 (2–3) | 2 (1–3) | |
| Charlson Comorbidity Index | ||||
| Mean (SD) | 1.5 (1.5) | 3.9 (1.7) | 2.2 (1.9) | <0.0001 |
| Median (range) | 1.5 (0–6) | 3.5 (1–8) | 2 (0–8) | |
| Surgery duration, min | ||||
| Mean (SD) | 116 (42) | 146 (51) | 125 (47) | 0.012 |
| Median (range) | 105 (63–253) | 135 (66–227) | 108 (63–253) | |
| Estimated blood loss,median (range) (IQR) | 0 (0–35) (0–0) | 0 (0–30) (0–8) | 0 (0–35) (0–0) | 0.21 |
| Total drain output, mL, median (range) (IQR) | 30 (0–235) (14–51) | 80 (30–505) (50–134) | 35 (0–505) (25–80) | <0.0001 |
Abbreviations: ASA, American Society of Anesthesiologists; IQR, interquartile range.
↵a Adjusted threshold for statistical significance P < 0.0063.