Baseline characteristics of included patients
| Characteristic | PTED (N=179) | OM (N=309) |
| Age—year (SD) | 45.3±12.4 | 45.7±11.3 |
| Male sex—no (%) | 99 (55.3) | 180 (58.3) |
| Current smoker—no (%) | 43 (24.0) | 91 (29.5) |
| Body mass index—kg/m2 | 26.6±4.1 | 26.8±5.4 |
| Paid employment—no (%) | 151 (84.4) | 242 (78.6) |
| Duration of sciatica—months | 4.2±3.0 | 4.2±2.9 |
| Radiating pain in the right leg—no (%) | 84 (46.9) | 155 (50.2) |
| Sensory disturbances—no (%) | 161 (89.9) | 290 (93.3) |
| Muscle weakness—no (%) | 92 (51.4) | 183 (59.2) |
| Difference in deep-tendon reflexes in the knees—no (%) | 48 (26.8) | 81 (26.4) |
| Difference in deep-tendon reflexes in the ankles—no (%) | 42 (23.5) | 77 (25.1) |
| Level of disc herniation causing sciatica—no (%) | ||
| L2–L3 | 2 (1.1) | 7 (2.3) |
| L3–L4 | 15 (8.4) | 13 (4.2) |
| L4–L5 | 68 (38.0) | 137 (44.3) |
| L5–L6 | 1 (0.6) | 2 (0.6) |
| L5–S1 | 93 (52.0) | 148 (47.9) |
| L6–S1 | 0 | 2 (0.6) |
| Score on the Visual Analogue Scale of pain* | ||
| Leg pain | 67.3±21.7 | 69.9±20.6 |
| Back pain | 48.7±27.6 | 45.4±29.7 |
| Oswestry Disability Index† | 44.5±16.9 | 45.5±17.1 |
| Score on the Visual Analogue Scale of quality of life‡ | 46.8±19.9 | 48.8±21.9 |
| SF-36 score§ | ||
| Physical component summary | 30.4±7.7 | 29.6±7.7 |
| Mental component summary | 47.4±10.8 | 46.5±11.3 |
| Four-dimensional symptom questionnaire¶ | ||
| Distress | 9.7±7.2 | 9.3±7.4 |
| Depression | 1.0±1.9 | 1.1±2.2 |
| Anxiety | 1.3±2.4 | 1.5±2.7 |
| Somatisation | 6.8±4.3 | 7.2±5.1 |
| Preference for PTED—no (%) | 85.5 | 77.9 |
One patient in the open microdiscectomy group had missing scores on the Oswestry Disability Index, VAS for QoL and back pain, Four-dimensional symptom questionnaire and Short-Form-36 at baseline. Values are means±SD.
*The visual-analogue scale scores the intensity of leg and back pain from 0 to 100 with higher scores indicating more pain.
†The Oswestry Disability Index measures functional disability from 0 to 100 with higher scores indicating more functional disability.
‡The visual-analogue scale of quality of life scores the general quality of life from 0 to 100 with higher scores indicating a better quality of life.
§The SF-36 score can be summarized in a physical component summary and a mental component summary using normative data. Higher scores indicate a better quality of life.
¶The four-dimensional symptom questionnaire measures distress in four categories.
PTED, percutaneous transforaminal endoscopic discectomy; QoL, quality of life; VAS, Visual Analogue Scale.