| Male：Female | 17 : 13 | 20:10 | 16:14 | 0.551 |
| Age (years) | 67.3±10.64 | 62.1±13.01 | 63.0±13.68 | 0.229 |
| Body mass index (BMI) | 23.0±3.84 | 24.6±3.41 | 23.4±3.65 | 0.236 |
| Previous operation history | 7 (23.3%) | 7 (23.3%) | 11 (36.7%) | 0.412 |
| Preop.§ radiotherapy | 2 (6.7%) | 0 (0%) | 1 (3.3%) | 0.770 |
| Preop.§ mucosectomy | 1 (3.3%) | 2 (6.7%) | 5 (16.7%) | 0.263 |
| Anesthetic time (minutes) | 219.8±47.46 | 267.5±31.20 | 286.0±46.73 | 0.000 |
| Operative time (minutes) | 164.7±46.94 | 208.7±29.91 | 228.8±47.17 | 0.000 |
| Length of hospital stay after op.∥ (days) | 16.5±8.57 | 11.9±4.95 | 12.1±3.39 | 0.005 |
| Estimated blood loss (ml) | 150.7±121.53 | 151.7±115.88 | 138.9±162.46 | 0.925 |
| Amount of RBC¶ (pints) | 1.2±2.02 | 0.6±0.97 | 0.4±1.19 | 0.094 |
| Drain removal (day) | 7.7±3.96 | 6.3±3.04 | 5.7±1.69 | 0.033 |
| Sips start (day) | 5.3±2.07 | 4.8±1.29 | 5.0±0.89 | 0.520 |
| Duration of usage of nalbuphine (days) | 1.5±2.18 | 0.4±1.16 | 0.5±1.36 | 0.022 |
| Postoperative complication | 7 (23.3%) | 3 (10.0%) | 4 (13.3%) | 0.439 |