Table 2 Summary of included studies

Hall et al. ( 2007) [18]

To investigate the efficacy of the treatment of C1-C2 self-SNAG and the effects on the change of FRT and symptoms related to cervicogenic headache

n = 32

13 M; 19 F

MA: 36 years /

Performed by 3 professionals/

RCT-Parallel

Trial Period: 12 months

CG: False mobilization of C1-C2 using the cervical self-SNAG strap 2 times a day

SG1: Self mobilization (self-SNAG) of C1-C2 using the cervical self-SNAG strap 2 times a day

FRT

MMHI

CG: ↑ FRT ( p < 0.001); = MMHI

SG1: ↑ FRT ( p < 0.001); ↑ MMHI( p < 0.001)

FRT: SG1 > CG

MMHI: SG1 > CG

Shin and

Lee, (2014)

[19]

To investigate the effect of the SNAG technique on the duration of headache in middle-aged women with CH

n = 40

37 F

MA: 45 years /

Performed by 3 professionals /

RCT-Parallel

Trial Period: 7 weeks

CG: Placebo mobilization of the neck area with pain—3 × week (20 min) for 4 weeks

SG1: SNAG technique—3 × week (20 min) for 4 weeks

VAS

NDI

HD

CG: ↑ VAS ( p < 0.05); ↑ HD ( p < 0.05); ↑ NDI ( p < 0.05)

SG1: ↑ VAS ( p < 0.05); ↑ HD ( p < 0.05); ↑ NDI ( p < 0.05)

VAS: SG1 > CG

NDI: CG = SG1

HD: SG1 > CG

Wade and Franklin, (2015) [16]

To study the effects of the SNAG technique and strengthening muscles in the cervical spine in the relief of cervicogenic headache

n = 30/

M;F (Not specified)

MA: 35 years/

Performed by 2 professionals/

RCT-Parallel

Trial Period: 1 week

CG: TENS in the paraspinal region of the cervical spine combined with deep muscle strengthening for the cervical region

SG1: C1-C2 SNAG 10 × 10 s, combined with deep muscle strengthening for the cervical region

VAS

SDCM

GC: ↑ VAS( p < 0.000); SDCM

( p < 0.000)

SG1: ↑ VAS( p < 0.000); SDCM( p < 0.000)

VAS: SG1 > CG

SDCM: SG1 = CG

Christian (2017)

[20]

Search for the effects of SNAG (Mulligan) and PA (Maitland) techniques on cervicogenic headache and compare them with a control group

n = 23

12 M; 11 F

MA: 30 years/

(Not specified)/

RCT-Parallel

Trial Period: 1 week

CG: n = 6 sessions (active neck exercises + strengthening and stretching exercises)

SG1: n = 6 SNAG sessions

(4 × 10 s.)

SG2: n = 6 sliding sessions central PA, lateral PA (from 3 × 60 to 5 × 120 oscillations)

FRT

HDI

CG: ↑ FRT ( p < 0.05)

SG1: ↑ FRT ( p < 0.05);

SG2: ↑ FRT ( p < 0.05)

FRT: CG = SG1 = SG2

HDI1: CG > SG2

Patra, Mohanty,

Gautam (2017)

[17]

Evaluate the effectiveness of dry needling combined with SNAG C1-C2 in improving PPT and reducing disability due to cervicogenic headache

n = 114

37 M; 77F

MA: 37 years/

Performed by 3 professionals/

RCT-Parallel

Trial Period: 6 weeks

SG1: Dry Needling

SG2: C1-C2 SNAG

SG3: GE1 + GE2

HDI

PPT-1

PPT-2

PPT-3

SG1: ↑ HDI ( p < 0.001); ↑ PPT-1 ( p < 0.001); ↑ PPT-2 ( p < 0.001); ↑ PPT-3 ( p < 0.001);

SG2: ↑ HDI ( p < 0.001); ↑ PPT-1 ( p < 0.001);

SG3: ↑ HDI ( p < 0.001); ↑ PPT-1 ( p < 0.001); ↑ PPT-2 ( p < 0.001); ↑ PPT-3 ( p < 0.001);

HDI: SG3 > SG2 > SG1

PPT-1: SG3 > SG2 > SG1

PPT-2: SG3 > SG1 > SG2

PPT-3: SG3 > SG1 > SG2

Kirthika et al. (2018)

[21]

To compare the effects of the SNAG and MET techniques on the life management of subjects with cervicogenic headache

n = 30

6 M; 24 F

MA: 26 years/

Performed by 4 professionals/

RCT-Parallel

Trial Period: 4 weeks

SG1: SNAG 3 sets of 5 repetitions SG2:MET 6 sets de 5 repetitions

VAS

HDI

SG1: ↑ VAS ( p < 0.001); ↑ HDI2 ( p < 0.001)

SG2: ↑ VAS ( p < 0.0001); ↑ HDI2 ( p < 0.001)

VAS: SG2 > SG1

HDI2: SG2 > SG1

Mohamed et al. (2019)

[22]

To determine the effect of the SNAG technique on C1-C2 on cervicogenic headache and associated dizziness

n = 48

28 M; 20F

MA: 29 years/

Performed by a therapist/

RCT-Parallel

Trial Period: 6 months

SG1: SNAG C2 (10 × 10 s. / 30 s rest each repetition)

SG2: C1-C2 SNAG Half-Rotation (10 × 10 s / 30 s of rest each repetition)

SG3: Combination of GE1 + GE2

(5 repetitions of each technique)

NDI

DHI

FRT

SG1: ↑ FRT (p < 0.001); ↑ DHI (p < 0.001)

SG2: ↑ FRT (p < 0.001); ↑ DHI (p < 0.001)

SG3: ↑ NDI (p < 0.001); ↑ FRT

(p < 0.001); ↑ DHI (p < 0.001)

NDI: SG3 > SG1 = SG2

FRT: SG3 > SG1 = SG2

DHI: SG1 > SG3 > SG2

Kashif et al. (2021) [23]

To investigate the effect of SNAGs in the treatment of cervicogenic headache

n = 40

0 M; 40 F

MA: 22 years/

Performed by a manual therapist/

RCT-Parallel

Trial Period: 4 weeks

SG1: 10 × 10 s; 3 × week (20 min; 12 sessions)

CG: received placebo treatment (contact pressure of the hand touching the disturbed joint) 10 × 10 s; 3 × week (20 min; 12 sessions)

VAS (assessed on week 1, 2, 3 and 4)

SG1: ↑ VAS ( p < 0.001)

VAS: SG1 > CG on week 3 ( p < 0.001) and week 4 ( p < 0.001)