Table 5.
Comparison of different phases according to the result of CUSUM analysis
| Variable | Phases | p-value | χ2 | F/t | H/Z | |||
|---|---|---|---|---|---|---|---|---|
| Total | Learning phase (n = 54) | Practicing phase | Mastery phase (n = 143) | |||||
| Operating time (min) | 168.37 ± 53.69 | - | 134.27 ± 41.04 | 0.000 | - | 4.225 | - | |
| EBL (mL), median (IQR) | 100 (50–100) | - | 50 (50–100) | 0.359 | - | - | 0.917 | |
| Postoperative hospital stays (day) | 7.01 ± 2.78 | - | 5.87 ± 2.28 | 0.003 | - | 2.972 | - | |
| Surgical failure, n (%) | 6 (11.1) | - | 6 (4.20) | 0.093 | - | - | - | |
| UBE-ULBD | ||||||||
| Operating time (min) | 188.48 ± 55.61* | 162.19 ± 55.45* | 136.98 ± 39.85* | 0.000 | - | 9.220 | - | |
| EBL (mL), median (IQR) | 100 (50–100) | 100 (50–100) | 100 (50–100) | 0.816 | - | - | 0.406 | |
| Postoperative hospital stays (day) | 6.81 ± 2.35* | 6.50 ± 1.86 | 5.88 ± 1.85* | 0.140 | - | 2.006 | - | |
| Surgical failure, n (%) | 3 (9.68) | 2 (5.56) | 2 (5) | 0.701 | 0.817 | - | - | |
| UBE-LD | ||||||||
| Operating time (min) | 152.92 ± 26.33*,† | 124.45 ± 37.07* | 117.36 ± 17.06† | 0.000 | - | 10.879 | - | |
| EBL (mL), median (IQR) | 100 (100–200)* | 100 (50–100) | 50 (50–100)* | 0.004 | - | - | 11.226 | |
| Postoperative hospital stays (day) | 7.92 ± 3.68* | 6.90 ± 3.40 | 5.26 ± 2.27* | 0.003 | - | 6.055 | - | |
| Surgical failure, n (%) | 2* (16.67) | 3† (15) | 0*,† (0) | 0.005 | 9.918 | - | ||
Values are presented as mean±standard deviation unless otherwise indicated.
CUSUM, cumulative sum; EBL, estimated blood loss; IQR, interquartile range; UBE-ULBD, unilateral biportal endoscopy unilateral laminotomy bilateral decompression; UBE-LD, unilateral biportal endoscopy lumbar discectomy.
*,†
p<0.05, pairwise comparison between groups.