Neck pain and headache: Pathophysiology, treatments and future directions

INTRODUCTION

Neck pain is a prevalent neurologic and musculoskeletal complaint in the general population and is often associated with primary headache disorders such as migraine and tension-type headache (TTH). A considerable proportion, ranging from 73% to 90%, of people with migraine or TTH also experience neck pain, and there is a positive correlation between headache frequency and neck pain. Furthermore, neck pain has been identified as a risk factor for migraine and TTH. Although the exact underlying mechanisms linking neck pain to migraine and TTH remain uncertain, pain sensitivity appears to play an important role. People with migraine or TTH exhibit lower pressure pain thresholds and higher total tenderness scores compared with healthy controls.

PURPOSE

This position paper aims to provide an overview of the current evidence on the relationship between neck pain and comorbid migraine or TTH. It will encompass the clinical presentation, epidemiology, pathophysiology, and management of neck pain in the context of migraine and TTH.

IMPLICATIONS

The relationship between neck pain and comorbid migraine or TTH is incompletely understood. In the absence of robust evidence, the management of neck pain in people with migraine or TTH relies mostly on expert opinion. A multidisciplinary approach is usually preferred, involving pharmacologic and non-pharmacologic strategies. Further research is necessary to fully dissect the linkage between neck pain and comorbid migraine or TTH. This includes the development of validated assessment tools, evaluation of treatment effectiveness, and exploration of genetic, imaging, and biochemical markers that might aid in diagnosis and treatment.

Evidence of localized and widespread pressure pain hypersensitivity in patients with tension-type headache: A systematic review and meta-analysis

OBJECTIVE

This meta-analysis evaluates pressure pain sensitivity values in symptomatic and distant pain-free areas comparing individuals with tension-type headache to controls.

DATABASES AND DATA TREATMENT

Electronic databases were searched for cross-sectional or prospective case-control studies comparing pressure pain thresholds in patients with tension-type headache to headache-free controls. Data were extracted by three reviewers. The methodological quality was assessed by the Newcastle-Ottawa Quality Assessment Scale. Meta-analyses of trigeminal, extra-trigeminal (neck) and distant pain-free areas in tension-type headache were compared to headache-free controls. Frequency of tension-type headache and gender were taken into account.

RESULTS

Twenty studies were included. Patients with tension-type headache exhibited lower pressure pain thresholds than headache-free controls: Trigeminal (MD -49.11 kPa, 95% CI -66.05 to -32.17), cervical spine (MD -88.17 kPa, 95% CI -108.43 to -67.92) and distant pain-free areas (MD -98.43 kPa, 95% CI -136.78 to -60.09). Differences were significant for chronic, episodic, and mixed episodic and chronic tension-type headache within the trigeminal and neck (symptomatic areas), but only significant for chronic tension-type headache (MD -102.86, 95% CI -139.47 to -66.25 kPa) for distant pain-free areas. In general, women had lower pressure pain thresholds than men. The methodological quality ranged from fair (45%) to good (40%). The results showed a high heterogeneity and publication bias.

CONCLUSION

This first meta-analysis addressing pressure pain thresholds differences in symptomatic and distant pain-free areas between patients with tension-type headache and controls found low to moderate evidence supporting the presence of pressure pain hypersensitivity in the trigeminal and neck areas in tension-type headache in comparison with headache-free controls. Sensitivity to pressure pain was widespread only in chronic, not episodic, tension-type headache (moderate evidence).Registration number: https://doi.org/10.17605/OSF.IO/R29HY.

Pressure pain thresholds over the cranio-cervical region in headache: a systematic review and meta-analysis

BACKGROUND

Sensitivity of tissues can be measured by algometry. Decreased pressure pain thresholds over the cranio-cervical area are supposed to reflect signs of sensitization of the trigemino-cervical nucleus caudalis. A systematic review was conducted to assess the current scientific literature describing pressure pain threshold (PPT) values over the cranio-cervical region in patients with migraine, tension-type headache (TTH), and cervicogenic headache (CeH). A literature search was executed in three databases. The search strategy included the following keywords: migraine, TTH, CeH, PPT and algometry. A total of 624 papers was identified of which relevant papers were subsequently assessed for methodological quality. Twenty-two selected papers were assessed by two independent reviewers and the majority of studies scored low risk of bias on the selected items. Mean PPT values of several sites measured in the cranio-cervical region in patients with migraine, chronic TTH and CeH scored lower values compared to controls. The trapezius muscle (midpoint between vertebrae C7 and acromion) was the most frequently targeted site and showed significantly lower PPT values in adults with migraine (pooled standardized mean difference kPa: 1.26 [95%CI -1.71, -0.81]) and chronic TTH (pooled standardized mean difference kPa: -2.00 [95%CI -2.93, -1.08]). Most studies found no association between PPT values and headache characteristics such as frequency, duration or intensity. Further standardization of PPT measurement in the cranio-cervical region is recommended.

Assessment of deep dynamic mechanical sensitivity in individuals with tension-type headache: The dynamic pressure algometry

BACKGROUND

To explore the validity of dynamic pressure algometry for evaluating deep dynamic mechanical sensitivity by assessing its association with headache features and widespread pressure sensitivity in tension-type headache (TTH).

METHODS

One hundred and eighty-eight subjects with TTH (70% women) participated. Deep dynamic sensitivity was assessed with a dynamic pressure algometry set (Aalborg University, Denmark^© ) consisting of 11 different rollers including fixed levels from 500 g to 5300 g. Each roller was moved at a speed of 0.5 cm/s over a 60-mm horizontal line covering the temporalis muscle. Dynamic pain threshold (DPT-level of the first painful roller) was determined and pain intensity during DPT was rated on a numerical pain rate scale (NPRS, 0-10). Headache clinical features were collected on a headache diary. As gold standard, static pressure pain thresholds (PPT) were assessed over temporalis, C5/C6 joint, second metacarpal, and tibialis anterior muscle.

RESULTS

Side-to-side consistency between DPT (r = 0.843, p < 0.001) and pain evoked (r = 0.712; p < 0.001) by dynamic algometer was observed. DPT was moderately associated with widespread PPTs (0.526 > r > 0.656, all p < 0.001). Furthermore, pain during DPT was negatively associated with widespread PPTs (-0.370 < r < -0.162, all p < 0.05).

DISCUSSION

Dynamic pressure algometry was a valid tool for assessing deep dynamic mechanical sensitivity in TTH. DPT was associated with widespread pressure sensitivity independently of the frequency of headaches supporting that deep dynamic pressure sensitivity within the trigeminal area is consistent with widespread pressure sensitivity. Assessing deep static and dynamic somatic tissue pain sensitivity may provide new opportunities for differentiated diagnostics and possibly a new tool for assessing treatment effects.

SIGNIFICANCE

The current study found that dynamic pressure algometry in the temporalis muscle was associated with widespread pressure pain sensitivity in individuals with tension-type headache. The association was independent of the frequency of headaches. Assessing deep static and dynamic somatic tissue pain sensitivity may provide new opportunities for differentiated diagnostics and possibly a tool for assessing treatment effects.

Lower mechanical pressure pain thresholds in female adolescents with patellofemoral pain syndrome

STUDY DESIGN

Cross-sectional study.

OBJECTIVES

To compare pressure pain thresholds (PPTs) between adolescent females diagnosed with patellofemoral pain syndrome (PFPS) and gender- and age-matched controls without musculoskeletal pain.

BACKGROUND

PFPS is prevalent among adolescents and may be associated with reduced PPT both locally and remotely from the site of reported pain. This may indicate altered central processing of nociceptive information. However, this has never been investigated in adolescents with PFPS.

METHODS

Adolescents with PFPS and a comparison group without musculoskeletal pain were recruited from a population-based cohort of students from 4 upper secondary schools, aged 15 to 19 years. All 2846 students within that age range were invited to answer an online questionnaire regarding musculoskeletal pain. The students who reported knee pain were contacted by telephone and offered a clinical examination by an experienced rheumatologist, who made a diagnosis. PPTs were measured at 4 sites around the knee and 1 site on the tibialis anterior in the 57 female adolescents diagnosed with PFPS and in 22 female adolescents without musculoskeletal pain.

RESULTS

Adolescents with PFPS, compared to controls, had significantly lower PPTs (26%-37% [100-178 kPa]) at each of the 4 sites around the knee, suggesting localized hyperalgesia. On the tibialis anterior, adolescents with PFPS had a 33% (159 kPa) lower PPT (distal hyperalgesia) compared with controls.

CONCLUSION

These findings suggest that adolescent females with PFPS have localized and distal hyperalgesia. These findings may have implications for treating PFPS, as both peripheral and central mechanisms may be driving the pain. Registered at clinicaltrials.gov (NCT01438762).

Referred pain from myofascial trigger points in head and neck-shoulder muscles reproduces head pain features in children with chronic tension type headache

Our aim was to describe the referred pain pattern and areas from trigger points (TrPs) in head, neck, and shoulder muscles in children with chronic tension type headache (CTTH). Fifty children (14 boys, 36 girls, mean age: 8 ± 2) with CTTH and 50 age- and sex- matched children participated. Bilateral temporalis, masseter, superior oblique, upper trapezius, sternocleidomastoid, suboccipital, and levator scapula muscles were examined for TrPs by an assessor blinded to the children's condition. TrPs were identified with palpation and considered active when local and referred pains reproduce headache pain attacks. The referred pain areas were drawn on anatomical maps, digitalized, and also measured. The total number of TrPs was significantly greater in children with CTTH as compared to healthy children (P < 0.001). Active TrPs were only present in children with CTTH (P < 0.001). Within children with CTTH, a significant positive association between the number of active TrPs and headache duration (r (s) = 0.315; P = 0.026) was observed: the greater the number of active TrPs, the longer the duration of headache attack. Significant differences in referred pain areas between groups (P < 0.001) and muscles (P < 0.001) were found: the referred pain areas were larger in CTTH children (P < 0.001), and the referred pain area elicited by suboccipital TrPs was larger than the referred pain from the remaining TrPs (P < 0.001). Significant positive correlations between some headache clinical parameters and the size of the referred pain area were found. Our results showed that the local and referred pains elicited from active TrPs in head, neck and shoulder shared similar pain pattern as spontaneous CTTH in children, supporting a relevant role of active TrPs in CTTH in children.

Generalized mechanical nerve pain hypersensitivity in children with episodic tension-type headache

OBJECTIVES

The objective of this study was to analyze the presence of generalized pressure pain hypersensitivity over nerve tissues in trigeminal and nontrigeminal regions in children with frequent episodic tension-type headache (FETTH).

METHODS

Thirty children, 7 boys and 23 girls (mean age: 8.8 +/- 1.7 years) with FETTH and 50 age- and gender-matched healthy children (14 boys, 36 girls; mean age: 8.5 +/- 2.1 years; P = .743) were recruited. Pressure pain thresholds (PPTs) were bilaterally assessed over supra-orbital (V1), infra-orbital (V2), mental (V3), median (C5), radial (C6), and ulnar (C7) nerves by an assessor who was blinded to the patient's condition.

RESULTS

The analysis of variance showed that PPT levels were significantly bilaterally decreased over both trigeminal (supra-orbital, infra-orbital, and mental) and nontrigeminal (median, ulnar, and radial) nerves in children with FETTH as compared with control subjects (all sites, P < .001). There was a greater magnitude of PPT decrease within trigeminal nerves as compared with nontrigeminal nerves (P < .03). PPTs over infra-orbital (r(s) = -0.4, P < .05) and radial (r(s) = -0.5, P < .01) nerves were negatively correlated with the duration of headache attacks (P < .05).

CONCLUSIONS

Our study revealed bilateral and generalized pressure hypersensitivity over both trigeminal and nontrigeminal nerves in children with FETTH. Diffuse hypersensitivity of peripheral nerves evidences the presence of hyperexcitability of the central nervous system in children with FETTH.

Bilateral, wide-spread, mechanical pain sensitivity in children with frequent episodic tension-type headache suggesting impairment in central nociceptive processing

Introduction: The aim was to investigate bilateral, wide-spread pressure pain hyperalgesia in symptomatic (trigeminocervical) and non-symptomatic (pain-free distant) regions in children with frequent episodic tension-type headache (FETTH).

Methods: Twenty-five children, 6 boys and 19 girls (mean age, 8.9 ± 1.8 years) with FETTH and 50 age- and sex-matched healthy children (12 boys, 38 girls; mean age: 8.8 ± 1.7 years) were recruited. Pressure pain thresholds (PPTs) were bilaterally assessed over temporalis muscle, upper trapezius muscle, second metacarpal and tibialis anterior muscles in a blinded design.

Results: The results showed that PPT levels were significantly decreased bilaterally over the temporalis, upper trapezius and tibialis muscles, and the second metacarpal in children with FETTH as compared to controls (all sites, P < 0.001). No significant differences in the magnitude of PPT decrease between the upper trapezius muscle, second metacarpal and tibialis anterior muscles were found. PPT over both upper trapezius muscles were negatively correlated with the history and intensity of headache (rs = −0.415; P = 0.045).

Conclusions: The findings revealed bilateral, wide-spread pressure pain hypersensitivity in children with FETTH suggesting that wide-spread central sensitisation is involved in children with this headache pain condition.

Mechanical allodynia and hyperalgesia in nerve and muscles in chronic tension-type headache

Evidence suggests that the most prominent finding in chronic tension-type headache (CTTH) is an increased tenderness to palpation of pericranial muscle tissues. Furthermore, lowered pain detection and tolerance thresholds found in CTTH suggest both allodynic and hyperalgesic response to pressure stimulation. Nevertheless, whether this mechanical hypersensitivity is a primary or a secondary phenomenon to CTTH is not clear. One recent study has demonstrated that pain sensitivity is a consequence not a causative factor of CTTH. Additionally, nerve tissues have also been found to be sensitized in CTTH. Recent evidence is modifying previous knowledge about relationships between muscle tissues and CTTH, since it has been found that trigger points, but not tender points, are responsible for peripheral nociceptive inputs in CTTH. An updated pain model suggests that headache perception can be explained by referred pain from active trigger points in the craniocervical muscles, mediated through the spinal cord and the trigeminal nucleus caudalis rather than only tenderness (tender points) of the muscles themselves.

Increased Pericranial Tenderness, Decreased Pressure Pain Threshold, and Headache Clinical Parameters in Chronic Tension-type Headache Patients

OBJECTIVE

The aim was to investigate whether increased pericranial tenderness or decreased pressure pain threshold (PPT) was related to headache intensity, duration, and frequency in chronic tension-type headache (CTTH).

METHODS

Twenty-five CTTH patients and 25 matched controls were studied. A headache diary was kept for 4 weeks to substantiate the diagnosis and record the pain history. Three tenderness (total, cephalic, and neck) scores and PPT at both cephalic and neck points were objectively and blinded assessed. Bodily pain perceived by the patients was assessed with the Short Form-36 questionnaire.

RESULTS

CTTH patients showed decreased PPT and increased tenderness as compared with controls (P<0.001). Negative correlations were found between PPT on each point and their respective tenderness scores. Within the CTTH group, neither increased tenderness nor decreased PPT seemed to directly influence headache intensity, frequency or duration; or vice versa.

DISCUSSION

Increased tenderness may predispose the patients to other perpetuating factors in inducing headache attacks. Further research is needed to clearly define the role of pericranial tender tissues or other factors in the genesis and maintenance of CTTH.