Table 1 Primary and secondary outcome parameters
Primary outcome parameter | Oswestry Disability Index (ODI), German and Austrian version, at 5 years’ follow-up to measure degenerative lumbar disc-related disability. [11, 12] |
Secondary outcome parameter | Changes in health status and quality of life will be captured by the Short Form-36 (SF-36) version 2.0 questionnaire [14] and EuroQuality of Life 5-Dimension-3 L (EQ-5D-3 L) questionnaire [13] |
Pain relief, as defined by improvement on 100 mm visual analog scale for back and leg pain [15]. | |
Index level and adjacent disc on magnetic resonance imaging (MRI) | |
• by evidence of disc degeneration (Pfirrmann Classification) or osteochondrosis (Modic Changes) [30–32] | |
• by numerical measurements in disc high, volumetry, and signal intensity | |
• by T2 relaxation | |
• by the presence or absence of stenosis. | |
Pain medication usage will be assessed by a four-level score (0 = none to 3 = high level of usage). | |
Work status and time to return to work | |
Neurological status will be evaluated using the Jenny Scale as a neurological test for the lower extremities, including motor and sensory deficits, reflexes, sciatic stretch ability and walking range. | |
Functional status: | |
• by posture and gait | |
• by finger-ground distance | |
• by Schober’s sign | |
• by precision tenderness/pressure pain |