J Manipulative Physiol Ther. 2013 (Sep); 36 (7): 403—411 ~ FULL TEXT
Gema Bodes-Pardo, PT, MSc, Daniel Pecos-Martín, PT, PhD,
Tomás Gallego-Izquierdo, PT, PhD, Jaime Salom-Moreno, PT, MSc,
César Fernández-de-las-Peñas, PT, PhD, Ricardo Ortega-Santiago, PT, PhD
Clinician, Clínica Fisioterapia Santiago Vila,
San Fernando de Henares, Spain.
OBJECTIVE: The purpose of this preliminary study was to determine feasibility of a clinical trial to measure the effects of manual therapy on sternocleidomastoid active trigger points (TrPs) in patients with cervicogenic headache (CeH).
METHODS: Twenty patients, 7 males and 13 females (mean ± SD age, 39 ± 13 years), with a clinical diagnosis of CeH and active TrPs in the sternocleidomastoid muscle were randomly divided into 2 groups. One group received TrP therapy (manual pressure applied to taut bands and passive stretching), and the other group received simulated TrP therapy (after TrP localization no additional pressure was added, and inclusion of longitudinal stroking but no additional stretching). The primary outcome was headache intensity (numeric pain scale) based on the headaches experienced in the preceding week. Secondary outcomes included neck pain intensity, cervical range of motion (CROM), pressure pain thresholds (PPT) over the upper cervical spine joints and deep cervical flexors motor performance. Outcomes were captured at baseline and 1 week after the treatment.
RESULTS: Patients receiving TrP therapy showed greater reduction in headache and neck pain intensity than those receiving the simulation (P < .001). Patients receiving the TrP therapy experienced greater improvements in motor performance of the deep cervical flexors, active CROM, and PPT (all, P < .001) than those receiving the simulation. Between-groups effect sizes were large (all, standardized mean difference, >0.84).
CONCLUSION: This study provides preliminary evidence that a trial of this nature is feasible. The preliminary findings show that manual therapy targeted to active TrPs in the sternocleidomastoid muscle may be effective for reducing headache and neck pain intensity and increasing motor performance of the deep cervical flexors, PPT, and active CROM in individuals with CeH showing active TrPs in this muscle. Studies including greater sample sizes and examining long-term effects are needed.
From the FULL TEXT Article:
Cervicogenic headache (CeH) is a secondary headache, which means “head pain with a cervical source.” [1, 2, 3] It is characterized by unilateral headache with symptoms and signs of neck involvement, for example, pain by movement, by external pressure over the upper cervical, and/or sustained awkward head positions. [2, 3] Prevalence rates for CeH varied in the general population because some studies have not detailed the criteria used to define the headache. Prevalence rates within the general population varied from 0.4% to 2.5%, [4, 5] with a female preponderance (2:1).  However, Sjaastad and Bakketeig  reported a prevalence of 4.1% with no female preponderance.
Physical therapy is commonly used for the management of individuals with CeH.  Previous systematic reviews reported preliminary evidence for the application of upper cervical spine mobilization or mobilization for the management of CeH. [9, 10, 11] A recent systematic review of manual therapies suggests that spinal manipulative might be an effective treatment in the management of CeH patients.  A survey study conducted in Australia revealed that upper cervical spine mobilization or manipulation was the most used intervention by physical therapists.  The physiologic basis of CeH pain lies in the convergence between trigeminal afferents and afferents from the upper cervical spinal nerves in the trigeminocervical nucleus caudalis. [14, 15] Nociceptive afferent inputs into trigeminocervical nucleus may be originated by spondylosis, disk lesions, or facet arthropathies in the upper cervical spine. [16, 17] Therefore, therapeutic interventions targeted to tissues innervated by the trigeminocervical nucleus caudalis can be effective for the management of individuals with CeH.
Cervicogenic headache pain has been mostly related to joint, disk, and ligament pain from the upper cervical spine ; however, clinicians should consider that the upper cervical spine also receives afferent inputs from muscles. The role of referred pain to the head elicited by muscle tissues has received particular interest in recent years. [19, 20] It has been hypothesized that muscle trigger points (TrPs) can play a relevant role in the genesis of headache.  A TrP is usually defined as a hyperirritable spot within a taut band of a skeletal muscle that elicits a referred pain upon examination.  From a clinical viewpoint, TrPs can be classified as active or latent. Active TrPs are those which local and referred pain reproduces the pain symptoms, for example, reproduce the headache pattern.  Trigger points have been reported to be present in patients with tension type headache,  migraine,  and cluster headache.  In addition, active TrPs have been also related to neck pain, [24, 25] a common symptom experienced by individuals with CeH. [3, 5, 8] However, data related to TrPs in CeH are scarce. An old article reported an association between TrPs and CeH, although it was a case series.  Furthermore, there is 1 case report where the referred pain elicited by sternocleidomastoid muscle active TrPs reproduced the headache pain pattern in CeH.  In addition, treatment of this active TrP was effective for the management of this patient.  It is possible that active TrPs in this muscle can be present in a subgroup of patients with CeH. No studies to date have examined the effectiveness of TrP manual therapy over sternocleidomastoid muscle in patients with CeH exhibiting active TrPs in this muscle. Before conducting a randomized, controlled clinical trial, it is necessary to conduct a pilot study as a first step to determine the potential effects of the intervention and, in the case that no significant results were found, to obtain preliminary data for a potential sample size calculation (if needed). Therefore, the purpose of this study was to conduct a pilot randomized clinical trial to determine if such a study were feasible and to identify the preliminary effects of TrP manual therapy in individuals with CeH with sternocleidomastoid muscle active TrPs.
This study showed that a pilot trial could be conducted to determine if such a study were feasible. The study found preliminary findings that that manual therapy targeted to active TrPs in the sternocleidomastoid muscle may be effective for reducing headache and neck pain intensity and increasing motor performance of the deep cervical flexors, PPT, and active CROM when compared with simulated therapy in patients with CeH showing active TrPs in this muscle. Between-groups effect sizes were large for all the variables suggesting a clinical relevance of the changes after the treatment. In addition, between-group change scores surpassed the previously reported MCID for pain intensity. These results would support the hypothesis that, in patients with CeH where the referred pain from active TrPs in the sternocleidomastoid muscle reproduces the headache pain pattern, the application of TrP manual therapies can be an effective approach for these patients.
Our study is novel because previous studies investigating manual therapies in patients with CeH have only included joint interventions or exercise, but not TrP therapies. [10, 11, 12] There has only been 1 study where the authors applied TrP manual therapy to the masticatory muscle in individuals with CeH.  The results of our study are consistent with a previous case report where management of active TrP in the sternocleidomastoid muscle was effective for the treatment of a patient with CeH showing affectation of this muscle.  It should be noted that lower bound estimates of the 95% CIs for between-group changes exclude the MCID for pain intensity, the primary outcome, supporting statistically and clinically meaningful improvements in reduction of pain.
Some authors suggested that the sternocleidomastoid muscle may be a particularly common source of myofascial CeH.  Nevertheless, we should consider that not all patients with CeH exhibit active TrPs in the sternocleidomastoid muscle. In our study, at least 12 (24%) of 52 patients with CeH did not have active TrPs in this muscle. It would be interesting to determine the prevalence of active TrPs in the neck and head muscles in individuals with CeH.
The mechanisms why TrP manual therapy can be effective for reducing pain remain speculative.  Possible mechanisms include a reduction of TrP activity, restoration of the length of the muscle sarcomeres, reactive hyperemia within the TrP taut band, temporary elongation of the connective tissue, or reduction of sensitization mechanisms associated to TrPs. [45, 46] Another explanation may be that TrP manual treatment results in segmental antinociceptive effects.  In agreement with this hypothesis, we found significantly greater increases in PPT over the affected joints in those patients receiving TrP therapy. Again, between-groups differences exhibited large effect sizes, supporting a clinical effect of the intervention over mechanical sensitivity in those joints previously found to be hypersensitive in CeH.  The fact that TrP therapy decreases pressure pain sensitivity by increasing PPT is in line with a previous study.  Current and previous findings would support the antinociceptive effect of TrP interventions. Nevertheless, it is possible that different mechanisms are involved at the same time in the therapeutic effects of TrP manual treatment. Future studies are needed to determine the mechanisms effects of TrP manual therapies.
We also found that patients with CeH with active TrPs in the sternocleidomastoid muscle receiving TrP manual therapy experienced an increase in motor performance of the CCFT. This finding may be related to the fact that the sternocleidomastoid produces cervical flexion as its primary function. There is evidence associating relative excessive electromyographic activity of this muscle with weak deep cervical flexor activity during the CCFT. [37, 38] It has been found that patients with CeH also exhibit lower motor performance during the CCFT. [36, 50] Therefore, it is further possible that excessive activity of the sternocleidomastoid muscle during the CCFT induces TrP activation as previously suggested. [21, 39, 45] In fact, some studies have demonstrated that TrPs are associated with abnormal movement patterns  and increased motor neuron excitability  demonstrating the clinical relevance of TrPs in motor performance. In such scenario, manual therapies targeted to TrPs in the sternocleidomastoid muscle can restore the motor control performance of the CCFT.
Finally, we also found an increase in all CROMs after TrP manual therapy suggesting that TrP therapy can relive muscle tension of the taut bands in the sternocleidomastoid muscle. Our results agree with a previous study where patients with chronic neck pain and dizziness also exhibited increase in CROM after the application of ischemic compression over tender neck muscles.  In fact, we do not know if restoration of the length of the sarcomeres can be related to improvements in active CROM observed in those patients receiving TrP therapy. Because restricted CROM has been found to discriminate CeH from other headache subtypes,  it is expected an improvement of this outcome after a reduction of pain.
Although a potential strength of the current controlled clinical trial was the inclusion of a simulated therapy group, we should recognize potential limitations. The sample size was small, which was related to the fact that this was a pilot randomized, controlled study. Thus, clinical findings still need to be confirmed with larger studies. We only assessed the effects of TrP manual therapy at 1–week follow-up period, so we cannot be certain if differences remain in the long term. Subject selection was based on CeH clinical criteria and the presence of active TrP in the sternocleidomastoid muscle. Therefore, current results should not be extrapolated to all patients with CeH. As well, it is possible that the simulated TrP treatment could have provided some beneficial effects, although the pressure was minimal. Finally, only 1 therapist provided the treatment in the current study, which may limit the generalizability of the results. Future trials should address these issues and consider including multiple therapists delivering the interventions.
This study provides preliminary evidence that a trial of this nature is feasible. The findings of this pilot trial suggests that TrP manual therapy may be effective for reducing headache and neck pain intensity and pressure pain sensitivity and for increasing motor performance of the deep cervical flexors and active CROM in individuals with CeH showing active TrPs in the sternocleidomastoid muscle. Studies including large sample sizes and longer follow-up periods are suggested.
The application of manual therapy of active TrP in patients with
CeH improved pressure pain sensitivity, CROM, and deep
cervical flexors motor performance.
Manual therapy in active TrP point of sternocleidomastoid muscle
decreased the intensity of neck and head pain in individuals with CeH.
Future randomized controlled trials are necessary to determine the
validity of these results.