Table 1 Criteria list of methodological quality assessment of randomized controlled trials (RCTs) [7]
1. | Study population (30 points) |
(a) | Description of inclusion and exclusion criteria (1 point). Restriction to a homogeneous study population (1 point) |
(b) | Comparability of relevant baseline characteristics: duration of complaint (1 point), value of outcome measures (1 point), age (1 point), recurrences (1 point), and radiating complaints/associated symptoms (1 point) |
(c) | Description of the randomization procedure (2 points). Randomization procedure which excluded bias, i.e., random numbers table (2 points) |
(d) | Description of dropouts for each group and their reasons (3 points) |
(e) | Loss to follow-up: <20% loss to follow-up (2 points), or <10% loss to follow-up (4 points) |
(f) | Sample size: >50 subjects in the smallest group after randomization (6 points), or >100 subjects in the smallest group after randomization (12 points) |
2. | Interventions (30 points) |
(g) | Correct description of the manual intervention (5 points). All interventions described (5 points) |
(h) | Pragmatic study: comparison with an existing treatment modality (5 points) |
(i) | Co-interventions avoided in the design of the study (5 points) |
(j) | Comparison with a placebo control group (5 points) |
(k) | Mention of the experience of the therapist (5 points) |
3. | Measurement of effect (30 points) |
(l) | Placebo controlled studies: patients blinded (3 points), blinding evaluated and fully successful (2 points) or pragmatic studies: patients fully naive, evaluated and fully successful (3 points), time restriction of no manual treatments for at least 1 year (2 points) |
(m) | Outcome measures: pain assessment (2 points), global measure of improvement (2 points), functional status (2 points), spinal mobility (2 points), medical consumption (2 points) |
(n) | Each blinded outcome measure mentioned under item M earns 2 points |
(o) | Analysis of post-treatment data (3 points), inclusion of a follow-up period longer than 6 months (2 points) |
4. | Data presentation and analysis (10 points) |
(p) | Intention-to-treat analysis when loss to follow-up is <10% or intention-to-treat analysis as well as worst-case analysis for missing values when loss to follow-up is >10% (5 points) |
(q) | Corrected presentation of the data: mean or median with a standard deviation or percentiles for continuous variables (5 points) |