Effectiveness of sustained natural apophyseal glides in females with cervicogenic headache: A randomized controlled trial

Abstract

BACKGROUND:

Cervicogenic headache (CGH) is a common condition that results in significant disability. To treat this dysfunction, Mulligan described sustained natural apophyseal glides (SNAGs) as a manual therapy approach. However, only inconclusive short-term evidence exists for treating CGH with SNAGs.

OBJECTIVE:

The present study aims to investigate the effect of SNAGs in the treatment of CGH.

METHODS:

Fourty female patients ranging from 20 to 40 years with CGH were randomly assigned to two groups: 20 in a treatment group and 20 in a control group. SNAGs were applied to the treatment group while the control group received placebo treatment. Both groups received their respective treatment for 20 minutes, alternately three times per week, for a total of 12 times in four weeks. The outcome measures were the Neck Disability Index (NDI) and the Visual Analogue Scale (VAS). Participants were assessed at baseline and at the end of each week. The data was analyzed using SPSS version 20. Independent t-testing was used to reveal changes between groups. One-way ANOVA was used to determine changes within groups. The level of significance was $P<$ 0.05.

RESULTS:

Twenty participants (100%) in the treatment group and 17 (85%) in the control group had a history of headache aggravation with active movements or passive head positioning. There was no significant difference at baseline ( $p>$ 0.05), indicating that both groups were homogeneous at the time of recruitment. The $p$ value ( $p<$ 0.05) showed a significant difference in pain and level of disability at three and four weeks ( $p<$ 0.05) in patients treated with SNAGs. However, the cervical range of motion (ROM) showed a statistically significant improvement in flexion and extension in the treatment group ( $p<$ 0.05) while there was no significant improvement in side flexion and rotation ROM in both groups ( $p>$ 0.05).

CONCLUSION:

This study found that SNAGs were effective in reducing pain and neck disability and improved ROM in females with CGH.

Keywords

Cervicogenic headache females SNAGs

1. Introduction

In 1986, a Norwegian doctor explained the term cervicogenic headache (CGH) by identifying a subgroup of patients with headache associated with head and neck pain [1]. The World Cervicogenic Headache Society describes CGH as “… the discomfort raised to the parts of head, which is initiated due to a key cause (nociceptor) found in the matters of MSK (musculoskeletal) system, supplied by spinal nerves of cervical region” [2]. It has been reported that the prevalence of CGHs is between 0.4% and 2.5% in the general population and up to 36.20% in patients with headache symptoms [3]. Females are more disposed to CGH, which affects four times more women than men [4]. Sjaastad et al. [2] observed that CGH can be caused by a variety of cervical diseases and anticipated that the pathophysiology of CGH may be due to the consequences of afferent inputs that commence in the upper portion of the cervical vertebra into the vertebral column of the trigeminal nerve, including sensory inputs from the muscles of the cervical spine in the upper region, upper cervical facets, intervertebral discs of C2–C3, vertebral arteries, carotid artery and cranial fossa [2]. This is generally accompanied by higher dysfunction of the neck region, although other CGH mainly arises in patients with lower cervical dysfunction, predominantly following trauma [5, 6, 7].

It has been subsequently found that CGH includes a decreased cervical range of motion (ROM), tenderness and painful joints of the upper cervical spine, and muscular tightness mainly of the upper posterior soft tissues of the neck region in its chronic stages [8, 9]. Patients suffering cervical dysfunction frequently have weakened deep-neck flexor muscles. Numerous studies have concluded that all patients with CGH have complete reduction in strength or endurance of neck flexor muscles [10, 11]. The major risk factors causing CGH may consist of the following: overuse and repetitive activities, whiplash injuries, non-active life style, tension and depression, lack of moisture, forward twisting, rounded shoulders, overhead actions of the shoulder, and a forward head position [12, 13].

Manual therapy is defined as a clinical approach using hands-on training, including a number of techniques other than manipulation/mobilization, used by skilled practitioners to gain a number of benefits in diagnosing and treating soft tissues and joint structures for the purpose of alleviating pain; this includes relaxation by reducing edema, increasing the range of motion by enhancing tissue repair and extensibility of the surrounding structures, facilitating movement and decreasing the level of disability by improving musculoskeletal function for daily functioning [14]. In this context, Penas and Courtney identified a number of manual therapy techniques for the treatment of tension-headache and CGH by working on the theory of pain modulation. The therapies they mention are mobilization and manipulation, trigger point therapy, and a variety of exercises to reduce CGH pain [15]. A few investigations have suggested that SNAGs are an effective treatment for CGH [16, 17]. SNAGs have been defined as “… a persistent shifting of a specific part of vertebra when a motion is being performed.” It concerns the end range of motion of a joint [16, 18, 19]. CGH limits daily activities and even the anxiety of CGH can lead to avoidance of recreational activities. SNAGs therefore play a significant role in effectively handling CGH.

A review of the literature suggests that manual therapy is significantly helpful in improving the condition of CGH sufferers, although a number of other manual therapy techniques for the treatment of CGH are suggested [15]. Only a few case studies have been performed to evaluate the effects of SNAGs, so there is a gap in the literature regarding the application of SNAGs and their efficacy for CGH [20, 21].

Women have reported more complaints of neck pain and headaches [4]; therefore, it was decided that this trial will explore the effect of SNAGs in CGH among female university students. This study therefore aimed to examine the effect of SNAGs in CGH and to evaluate the level of improvement in pain intensity and NDI score in female university students with CGH.

2. Methods

This randomized controlled trial was conducted at the Physical Therapy Department of Safi Hospital, Faisalabad, Pakistan. The study was approved by the Ethical Review Committee of Riphah International University (RCRAHS/ERB/227) and registered under no. IRCT20200221046567N3. Subjects were randomly assigned into two groups following simple randomization procedures (computerized random numbers). Each participant received a written consent statement explaining the safe nature of the trial and their right to withdraw from it at any time. The study comprised 40 women aged between 20 and 40 years who suffered from CGH, fulfilled the diagnostic criteria of the International Headache Society (IHS) and who scored positive for a flexion-rotation test (FRT). Patients were excluded from the study who did not meet the age criteria for inclusion, or presenting a neurological deficit, and those with cervical spine injury, osteoporosis, fracture or surgery, congenital spinal deformity, cervical radiculopathy, history of recent trauma, migraine, disc herniation, and radiculopathy. The sample size for this randomized controlled trial was calculated by G Power 3.1 by using an a-priori sample size calculation. The participating patients were randomly assigned to two groups. The treatment group’s ( $n=$ 20) patients were treated with SNAGs while the control group’s ( $n=$ 20) patients received placebo treatment. The treatment procedure was performed by the manual therapist. The assessor was unaware of the treatment group to which the patients were assigned. However, due to the nature of the interventions, it was not possible to blind the patients or therapist.

2.1 Treatment group

The treatment group was treated with Mulligan SNAGs techniques to relieve neck pain and headache. Firstly, a manual therapist sat next to the patient. The trunk of the patient was grasped by the manual therapist who placed the head of the patient in her arm on the patient’s adjacent side. She then put her ring finger on the exaggerated point just above the small vertebral joints. After that, the manual therapist put the thenar eminence of the opposite hand of her ring finger on the affected small vertebral joint. At the same time, the manual therapist provided a sustained glide in upper direction (45 degrees); the thenar eminence of the opposite hand provided the power of the glide. The application of the glide was in a rhythmical manner at the rate of three times per second for ten seconds. The manual therapist continued to apply the glide to the spinous process. Meanwhile, the therapist asked the participant to move her head toward the side of limited range and pain. When the head of participant was moved thus, it was firmly fixed by the therapist with her hand on the spine of the vertebra (affected point) to sustain the SNAG and the patient was made to hold this position for about ten seconds. This glide was applied ten times over 20 minutes. At the end of the ROM of the cervical rotation, the patient used her own hand to perform a passive rotation (over-pressure). This newly gained pain-free range of motion was then held for two seconds and the glide was sustained until the neck slowly returned to its original position [22]. The SNAGs were applied for 20 minutes in each session of the treatment group, alternately three times per week, for a total of 12 times in four weeks.

2.2 Control group

The control group received placebo treatment for 20 minutes, alternately three times per week, for a total of 12 times in four weeks. A manual therapist who used the placebo effect for headaches stood next to a patient. The therapist did not use any other techniques other than the contact pressure of the hand touching the disturbed joint. The therapist stayed in position for at least ten seconds. This treatment was administered for ten repeats over 20 minutes per performance. This treatment was given three times a week for a total of 20 minutes per performance for 12 times in four weeks.

2.3 Outcome measures

The subjective outcomes including pain were measured using VAS, which has excellent reliability ( $r=$ 0.97) and high intra-rater reliability ( $r=$ 1.00) and inter-rater reliability ( $r=$ 0.99) [23]; NDI was used for evaluating neck disability. Farooq et al. reported that NDI had a high level of reliability with the Cronbach alpha coefficient ( $a=$ 0.96) [24]. The objective outcome, including cervical ROM, was measured by a universal goniometer. All movements of the cervical spine were performed: flexion, extension, side flexion to the right, side flexion to the left, rotation to the right and rotation to the left [25].

2.4 Statistical analysis and interpretation

Data was normally distributed. Quantile-quantile (QQ) plots were used to assess the normality of all variables. The QQ plots showed that pre- and post-variables were normally distributed with $p$ value $>$ 0.05.

The descriptive statistics of the study groups were presented by frequency tables, histograms and multiple bar charts. An independent $t$ -test was used to determine the improvement between groups in the form of subjective and objective measurements. Repeated measure ANOVA testing was used to determine the improvement within the groups between two consecutive visits in the form of subjective and objective measurements.

Table 1
General characteristics of the participants

	Treatment group	Control group		$P$ value
	( $n=$ 20)	( $n=$ 20)
Age (years)	22.20 $\pm$ 1.64	21.80	$\pm$ 1.54	0.064
Height (cm)	5.37 $\pm$ 0.20	5.33	$\pm$ 0.16	0.073
Weight (kg)	52.45 $\pm$ 8.68	53.05	$\pm$ 9.45	0.126
BMI (kg/m ${}^{2}$ )	19.58 $\pm$ 3.34	20.10	$\pm$ 3.48	0.204
What is the duration of your headache?	1.10 $\pm$ 0.068	1.35	$\pm$ 0.109	0.194
Does your headache aggravate with physical activity?	1.45 $\pm$ 0.11	6.85	$\pm$ 0.28	0.077
Pre-measurements of VAS	7.00 $\pm$ 0.30	6.85	$\pm$ 0.28	0.104
Pre-NDI score	22.10 $\pm$ 5.77	22.10	$\pm$ 5.77	0.091

BMI: Body Mass Index; VAS: Visual Analogue Scale; NDI: Neck Disability Index.

Figure 1.

Flowchart of the research process.

Figure 2.

Bar chart of change in VAS score across the two groups.

Table 2

Between-group comparison of VAS score

Study groups	Pre-measurement of VAS	Post-VAS week 1	Post-VAS week 2	Post-VAS week 3	Post-VAS week 4
Treatment group	7.00 $\pm$ 0.30	7.00 $\pm$ 0.30	6.30 $\pm$ 0.25	4.35 $\pm$ 0.19	1.80 $\pm$ 0.15
Control group	6.85 $\pm$ 0.28	6.85 $\pm$ 0.28	6.85 $\pm$ 0.28	6.55 $\pm$ 0.28	6.55 $\pm$ 0.28
$P$ value	0.722	0.722	0.156	0.000 ${}^{*}$	0.000 ${}^{*}$

VAS: Visual Analogue Scale, ${}^{*}$ : $p<$ 0.05.

Table 3

Between-group comparison of NDI score

Study groups	Pre-measurement of NDI	Post-NDI score week 1	Post-NDI score week 2	Post-NDI score week 3	Post-NDI score week 4
Treatment group	22.10 $\pm$ 5.77	22.10 $\pm$ 5.77	19.85 $\pm$ 5.07	16.55 $\pm$ 3.96	11.70 $\pm$ 3.29
Control group	22.10 $\pm$ 5.77	22.10 $\pm$ 5.77	22.05 $\pm$ 5.84	21.85 $\pm$ 6.10	20.45 $\pm$ 6.11
$P$ value	1	1	0.211	0.002 ${}^{*}$	0.000 ${}^{*}$

NDI: Neck Disability Index, ${}^{*}$ : $p<$ 0.05.

Table 4

Between-group comparison of cervical flexion

Study groups	Pre-measurement of cervical flexion	Post-1 week measurement of cervical flexion	Post-2 weeks measurement of cervical flexion	Post-3 weeks measurement of cervical flexion	Post-4 weeks measurement of cervical flexion
Treatment group	31.00 $\pm$ 1.86	32.30 $\pm$ 2.12	33.40 $\pm$ 1.93	34.90 $\pm$ 1.83	36.15 $\pm$ 2.05
Control group	31.00 $\pm$ 2.77	31.70 $\pm$ 2.61	32.00 $\pm$ 2.49	32.30 $\pm$ 2.53	32.75 $\pm$ 2.53
$P$ value	0.69	0.432	0.054	0.001	0

Table 5

Between-group comparison of cervical extension

Study groups	Pre-measurement of cervical extension	Post-1 week measurement of cervical extension	Post-2 weeks measurement of cervical extension	Post-3 weeks measurement of cervical extension	Post-4 weeks measurement of cervical extension
Treatment group	30.00 $\pm$ 0.85	30.85 $\pm$ 0.93	31.70 $\pm$ 0.65	32.45 $\pm$ 0.75	0.87 $\pm$ 0.99
Control group	29.90 $\pm$ 1.07	30.70 $\pm$ 1.12	31.05 $\pm$ 0.99	31.30 $\pm$ 0.80	32.05 $\pm$ 0.99
$P$ value	0.746	0.65	0.02	0	0

Figure 3.

Bar chart of change in NDI score across the two groups.

3. Results

A total 40 patients diagnosed with CGH were recruited as meeting the inclusion criteria. There were 20 persons (100%) in the treatment group and 17 (85%) in the control group who had a history of headache aggravation with active movements or passive head positioning. The symptom history of the treatment group was eight (40%) with nausea, four (20%) with phonophobia, three (15%) with photophobia, one (5%) with dizziness and four (20%) experiencing difficulty in swallowing or decreased appetite. The control group had five (25%) with nausea, one (5%) with phonophobia, seven (35%) with photophobia, two (10%) with dizziness and one (5%) with difficulty in swallowing or decreased appetite. There was no significant difference at baseline ( $p>$ 0.05), showing that both groups were homogeneous at the time of recruitment (Table 1). There was a significant difference in pain and level of disability in the treatment group at three and four weeks ( $p<$ 0.05) (Tables 2 and 3). However, the cervical ROM experienced statistically significant improvement in flexion and extension in the treatment group ( $p<$ 0.05) (Tables 4 and 5) while there was not significant improvement in side flexion and rotation ROM in both groups ( $p>$ 0.05).

4. Discussion

The present study was performed to evaluate the effect of SNAGs among female students. Its results demonstrated a marked improvement in the treatment group, with considerably reduced pain intensity and a reduction in neck disability levels over the control group.

This study concludes that patients in the treatment group exhibited superior improvement in pain and function levels, which were measured using VAS and NDI. The comparison between the two groups measured by VAS showed a pre-measurement $p$ value of 0.722, which reduced to 0.156 at the end of the second week and further reduced to $p$ value $<$ 0.001 at the end of the fourth week. Furthermore, the significance of SNAGs is demonstrated by the between-group comparison in NDI: the pre-score $p$ value was 1.000, decreasing to 0.211 at the end of the second week and to $<$ 0.001 at the end of the fourth week. The findings of this trial are the same as those of Shin E-J et al. [22], which concluded that female patients receiving SNAGs demonstrated better results compared to placebo SNAGs. The difference between their study and ours is that we have taken the weekly VAS and NDI scores through follow up, whereas they took the values pre- and post-treatment. Moreover, the age range in the present study is 20–40 years, while the age range in theirs was 30–60 [22].

The objective of this trial was to investigate the effect of SNAGs on pain, ROM and functional disability in female university students with CGH. The $p$ value of pain for the treatment group was $<$ 0.001 and 0.010 for the control group. As the $p$ value of the treatment group was less than 0.005, we can conclude that treatment using SNAGs was effective. An RCT study by Tachii et al. in 2015, with the principal aim of exploring the short-term effects of SNAGs in patients having a neck pain history of over three months, supported this study. Their results showed that the group with SNAGs improved better than the control group, demonstrating the same results as this study [26].

The present study demonstrated a noteworthy reduction in discomfort intensity and a considerable rise in function levels in the treatment group over the control group. The $p$ value of NDI for the treatment group ( $p<$ 0.001) compared to the control group ( $p=$ 0.116) at the end of the study showed that there was a statistically significant difference between the groups and revealed that SNAGs are more effective. The present study is further corroborated by the work of Khan et al. in comparing SNAGs and posterior anterior vertebral mobilization in patients with CGH at the atlanto-axial level. The results were significantly different ( $p<$ 0.001) and confirmed SNAGs as an effective treatment [27]. The study by Said et al. further supported the findings of this study as the results reported significant improvement in VAS and NDI scores and stated that self-mobilization and Mulligan SNAGs were equally effective for the cervical joint sense [28].

4.1 Limitations

The adaptation of the cervical muscle joint structure for exercise therapy may take longer than manipulation. The four-week period may be too early to compare both treatment methods. Therefore, studies with a treatment duration of more than four weeks to observe the long-term effects of SNAG should be conducted in the future. Moreover, post-treatment follow-up was not performed in the current study.

5. Conclusion

This study found that SNAGs are more effective in pain reduction, neck disability and improvement in cervical ROM for patients with CGHs. It also suggests that SNAGs may be used as an effective treatment for CGHs in regular clinical practice.

Footnotes

Conflict of interest

None to report.

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