Table 2 Key results of the binary logistic regression models

Patient age

1.05 (0.98–1.12)

0.195

1.00 (0.96–1.05)

0.954

1.03 (0.99–1.07)

0.176

Patient sex female (ref. male)

0.51 (0.09–2.79)

0.435

1.47 (0.45–4.84)

0.529

0.80 (0.26–2.41)

0.797

No radiation below gluteal fold (ref. radiation below gluteal fold)

2.97 (0.17–53.52)

0.461

3.28 (0.45–23.63)

0.239

0.14 (0.02–1.03)

0.138

Chiropractor (ref. non chiropractor)

1.42 (0.24–8.31)

0.701

32.26 (3.17–327.98)

0.003*

1.94 (0.50–7.51)

0.339

No implant (ref. implant)

1.04 (0.01–75.59)

0.985

0.27 (0.03–2.20)

0.789

0.43 (0.05–3.84)

0.449

Motion segments non-reduced (ref. reduced)

7.60 (0.14–406.79)

0.318

9.07 (0.97–84.64)

0.053

0.33 (0.35–3.19)

0.340

Post-surgical imaging (ref. no)

2.99 (0.34–26.06)

0.323

4.09 (0.47–35.83)

0.203

2.42 (0.57–10.20)

0.228

Lumbar SMT (ref. no)

NA

NA

NA

NA

2.26 (0.35–14.76)

0.395

Time to SMT > 1 year (ref. ≤ 1 year)

2.73 (0.33–23.01)

0.355

0.64 (0.15–2.82)

0.557

NA

NA