Table 1 Randomized controlled studies of spinal manipulations for the treatment of migraines

Chaibi (2017) [27]

Single-blind, sham-controlled RCT with 3 parallel groups

104 migraineurs

SMT

(i) Sham

(ii) Pharmacotherapy

(i) Migraine days per month

(ii) Duration

(iii) Intensity

(iv) Headache Index

(i) a. Mean (SD) 3.9 (3.1) vs 4.1 (5.7) (p = 0.20) at post-intervention

b. 4.5 (3.6) vs 4.6 (5.7) (p = 0.39) at 3 months follow-up

c. 4.1 (3.9) vs 5.1 (6.4) (p = 0.65) at 6 months follow-up

d. 4.4 (4.2) vs 4.1 (6.0) (p = 0.85) at 12 months follow-up

(ii) a. 9.2 (5.8) vs 10.4 (7.0) (p = 0.04) at post-intervention

b. 9.5 (6.9) vs 10.6 (7.2) (p = 0.06) at 3 months follow-up

c. 7.3 (7.1) vs 11.6 (7.4) (p = 0.12) at 6 months follow-up

d. 8.1 (7.3) vs 8.9 (7.7) (p = 0.34) at 12 months follow-up

(iii) a. 4.7 (2.8) vs 5.0 (3.0) (p = 0.27) at post-intervention

b. 5.0 (3.0) vs 4.9 (2.8) (p = 0.46) at 3 months follow-up

c. 4.4 (3.6) vs 5.2 (2.9) (p = 0.69) at 6 months follow-up

d. 5.1 (3.5) vs 4.4 (3.2) (p = 0.97) at 12 months follow-up

(iv) a. 295.5 (348.1) vs 330.1 (602.3) (p = 0.16) at post-intervention

b. 338.0 (350.8) vs 399.6 (582.0) (p = 0.32) at 3 months follow-up

c. 313.0 (395.6) vs 402.8 (595.1) (p = 0.56) at 6 months follow-up

d. 350.8 (451.6) vs 322.9 (668.8) (p = 0.92) at 12 months follow-up

Blinding successfully achieved in > 80% of patients

Munoz-Gomez (2021) [26]

Single-blind, sham-controlled RCT with 2 parallel groups

50 migraineurs

OMT

(i) Sham

(i) Intensity

(ii) Frequency

(iii) Disability

(iv) QoL

(i) a. Mean (SD) 6.4 (1.0) vs 7.9 (1.1) at 1 month (p < 0.001)

b. 6.5 (1.0) vs 7.6 (0.9) at 2 months (p < 0.001)

(ii) a. 22.0 (10.9) vs 23.2 (8.9) at 1 month (MD = 1.2; 95% CI − 4.5 to 6.8)

b. 20.6 (10.3) vs 23.4 (8.6) at 2 months (MD = 2.8; 95% CI − 2.6 to 8.2)

(iii) a. 30.2 (18.1) vs 33.9 (13.9) at 1 month (MD = 3.7; 95% CI − 5.5 to 12.9)

b. 24.3 (14.2) vs 34.3 (14.6) at 2 months (MD = 10.0; 95% CI 1.8 to 18.2; p < 0.05)

(iv) a. 66.9 (15.0) vs 57.7 (15.8) at 1 month (MD = − 9.3; 95% CI − 18.0 to − 0.5; p < 0.05)

b. 66.3 (21.1) vs 58.3 (14.9) at 2 months (MD = − 8.0; 95% CI − 18.4 to 2.4; n.s.)

Relatively well-designed and reported study

Nelson (1998) [32]

Quasi-RCT with 3 parallel groups

218 patients with migraine

SMT

(i) Drug therapy (amitriptyline)

(ii) SMT + amitriptyline

(i) Headache index

(ii) Severity

(iii) Frequency

(iv) Medication use

(i) a. Mean (SD) 11.1 (5.6) vs 8.4 (9.0) at post-treatment

b. 10.8 (9.6) vs 12.5 (8.3) at 1 month

(ii) a. 4.3 (1.5) vs 4.3 (1.6) at post-treatment

b. 4.4 (1.7) vs 4.5 (1.3) at 1 month

(iii) a. 37.5 (25.9) vs 26.8 (22.6) at post-treatment

b. 36.9 (29.3) vs 40.5 (23.3) at 1 month

(iv) a. 1.2 (1.2) vs 0.7 (0.9) at post-treatment

b. 1.2 (1.2) vs 1.3 (1.3) at 1 month

Manipulation group received more attention (14 visits) compared to max. of 3 visits for drug therapy group

Parker (1978) [34]

Quasi-RCT with 3 parallel groups

85 migraine patients

(i) SMT by chiropractor

(ii) SMT by a medical practitioner or physiotherapist

Mobilization

(i) Frequency of attacks

(ii) Duration of headaches (hours)

(iii) Disability

(iv) VAS for pain intensity

(i) Mean = 5.1 vs 5.7

(ii) 19.4 vs 11.9

(iii) 1.8 vs 2.2

(iv) 2.8 vs 4.5

(i) Lack of randomization,

(ii) Lack of control for placebo effects

Rist (2021) [25]

RCT with 2 groups

61 females with episodic migraines

SMT + UC

UC alone

(i) Migraine days

(ii) Severity

(iii) Duration

(iv) Disability (MIDAS)

(v) (Acute) medication use

(vi) QoL (emotional)

(i) a. mean change = − 1.92; 95% CIs − 3.46 to − 0.37) at weeks 11–14

b. − 1.71; 95% CI − 3.26 to − 0.16 at weeks 15–18

(ii) a. − 0.85 (− 1.77 to 0.06) at weeks 11–14

b. − 0.64 (− 1.65 to 0.38) at weeks 15–18

(iii) a. − 1.48 (− 3.44 to 0.48) at weeks 11–14

b. 0.31 (− 1.96 to 2.57) at weeks 15–18

(iv) a. − 5.58 (− 10.44 to − 0.72) at weeks 11–14

b. − 9.45 (− 17.47 to − 1.43) at weeks 15–18

(v) a. − 1.36 (− 3.48 to 0.76) at weeks 11–14

b. − 0.83 (− 3.20 to 1.53) at weeks 15–18

(vi) a. 3.60 (− 1.10 to 8.30) at weeks 11–14

b. 6.57 (2.78 to 10.36) at weeks 15–18

Tuchin (2000) [33]

Quasi-RCT with 2 groups

127 volunteers

SMT

Placebo (detuned interferential therapy)

(i) Frequency

(ii) Intensity

(iii) Duration

(iv) Disability

(v) Medication use

(i) mean (SD) = 4.1 (6.55) vs 6.9 (6.6) (p < 0.005)

(ii) 6.9 (1.8) vs 6.2 (1.7) n.s

(iii) 14.8 (19.8) vs 19.8 (17.7) (p < 0.01)

(iv) 13.0 (18.2) vs 15.6 (18.2) (p < 0.05)

(v) 9.8 (12.4) vs 16.2 (12.4) (p < 0.001)

(i) Unequal distribution of patients into groups,

(ii) Unjustified blinding

(iii) The use of a placebo is not credible