Patient characteristics
| Total sample (n=40) | |
| Sex | |
| Men, n (%) | 19 (47.5) |
| Women, n (%) | 21 (52.5) |
| Age, years | |
| Mean (SD) | 73 (6.7) |
| Min-max | 60–87 |
| Level of education | |
| Elementary school, n (%) | 11 (27.5) |
| Upper secondary school, n (%) | 13 (32.5) |
| Tertiary education, n (%) | 16 (40) |
| Living situation | |
| Lives with spouse or adult children, n (%) | 29 (72.5) |
| Lives with spouse and has home care, n (%) | 1 (2.5) |
| Lives alone, n (%) | 9 (22.5) |
| Lives alone and has home care, n (%) | 1 (2.5) |
| Mini Mental State Examination | |
| Mean (SD) | 28 (1.4) |
| American Association of Anesthesiologists’ physical status classification system | |
| I, n (%) | 5 (13) |
| II, n (%) | 18 (45) |
| III, n (%) | 17 (42) |
| Comorbidities | |
| Heart disease (eg, hypertension), n (%) | 24 (57) |
| Vascular disease, n (%) | 9 (21) |
| Lung disease, n (%) | 6 (14) |
| Kidney disease, n (%) | 1 (2) |
| Diabetes, n (%) | 5 (12) |
| History of cancer, n (%) | 8 (19) |
| Autoimmune disease, n (%) | 6 (14) |
| Type of anaesthesia | |
| Spinal, n (%) | 36 (90) |
| General, n (%) | 4 (10) |
| Duration of surgery, minutes (SD) | 114.5 (32.4) |
| Duration of anaesthesia, minutes (SD) | 188.5 (36.5) |
| Intraoperative bleeding, mL (SD) | 348 (148.9) |
| Postoperative days at the hospital, mean (SD) | 1.5 (0.6) |
| Preoperative pain, NRS, mean (SD) | 5.4 (3.2) |
| Postoperative pain day 14, NRS, mean (SD) | 2.1 (2.1) |
| Preoperative tryptophan, µmol/L, mean (SD) | 43.8 (9.5) |
| Postoperative tryptophan, µmol/L, days 13–16, mean (SD) | 41.9 (10) |
| Quality of recovery global score, days 13–16, mean (SD) | 40.9 (28.4) |
| Postoperative opioid treatment, day 14 | |
| Yes, n (%) | 17 (43) |
| No, n (%) | 23 (57) |
NRS, numeric rating scale.