Chiropractic + Naturopathic Doctor • March/April 2022 • Evidence-based case report

Chiropractic management of cervicogenic headaches: an evidence-based case report

Cervicogenic headaches are chronic and recurrent secondary headaches that are characterized by radiating pain emanating from the neck. These headaches present with a loss of cervical range of motion, along with unilateral headaches that migrate to the oculofrontotemporal area(1). Cervicogenic headache is the best understood of the common headaches (i.e., migraine, tension, cluster, and cervicogenic) because the referred pain that is perceived as a headache can be explained by the convergence of upper cervical and trigeminal afferents in the trigeminocervical nucleus. Nociceptive afferents from C1 through C3 spinal nerves converge onto the same second-order neurons that receive afferents from the first branch of the trigeminal nerve through the trigeminal nerve spinal tract. This convergence allows for upper cervical pain to be referred to the occipital and temporal regions of the head, as well as the ocular region(2).

Differentiation of cervicogenic headaches from migraines must be made as they have many common symptoms; both are unilateral headaches with a female preponderance and both may present with nausea, vomiting, photophobia and phonophobia, although patients with cervicogenic headaches present with the latter symptoms less frequently and to a lesser degree (3). In this case report, we have used an “evidence-based” format(4) to determine whether chiropractic manipulation is a more effective therapy than non-steroidal anti-inflammatory drugs (NSAIDs) in a patient presenting with cervicogenic headache.

A 28-year old pregnant female presented with chronic and recurrent neck pain and headaches. She had been suffering from headaches since she was 17 years old. The frequency and intensity of her headaches had worsened in the last 3 months due to increased work-related stress, as she had recently been promoted to a managerial position. She described her headaches as a “throbbing” pain throughout her left suboccipital, periorbital, and temporal regions, which were particularly worse at night and in the early morning hours. During headache episodes, she rated her pain severity at a 9/10 (with 0 being no pain and 10 being the worst pain possible). The patient denied any symptoms of aura, including visual “spots;” however, when her headaches were severe, she experienced photophobia, phonophobia, and nausea with vomiting. Due to being 24 weeks pregnant with her first child, she was worried about the adverse effects of medications for both herself and her baby. She was taking NSAIDs (Ibuprofen, 400 mg) prescribed by her family physician.

Neurological examination of dermatomes, myotomes and reflexes of her upper extremities as well as cranial nerve assessment revealed no remarkable findings. The range of motion of her cervical spine, as well as orthopedic testing, were within normal limits. Palpation revealed myofascial trigger points in the left suboccipital, temporal, and levator scapulae muscles. The patient also had tenderness upon palpation of the left C1-C3 facet joints. Based on her history and examination findings, our working diagnosis was cervicogenic headache. (Note: This case report was written as part of a third-year chiropractic course, Evidence- Informed Chiropractic Practice, at D’Youville College. As such, the report herein was based on a patient scenario rather than an actual patient.)

Due to the patient’s concerns about her current treatment plan of prescribed NSAIDs during pregnancy, she sought out alternative treatment, specifically chiropractic, in the hope of finding an alternative to pharmaceuticals. To use an evidence-based approach to inform the management of this case, we posed the following foreground question: In a 28-year-old pregnant female with worsening chronic cervicogenic headaches, is cervical spinal manipulative therapy (SMT) more effective than NSAIDs at reducing the severity and frequency of headache symptoms?

Using the mnemonic, PICO (i.e., Patient/problem, Intervention, Comparison, and Outcome[s] of interest), this question can be broken down as follows: P 28-year-old pregnant female with cervicogenic headaches; I Cervical SMT; C NSAIDs; O Reduced severity and frequency of headache symptoms

The best evidence to answer a clinical question about therapy is a systematic review of randomized controlled trials.5 Therefore, a search of the English language literature (from January 1, 2012 to June 5, 2021) was conducted using the National Library of Medicine (PubMed) database. Because our interest was in cervicogenic headaches, the key term ‘cervicogenic’ was used and our search settings were filtered to ‘systematic reviews’ and studies published between 2004 and 2021. This search yielded 65 results. The truncated term ‘chiropr*’ was then added with the Boolean operator ‘AND,’ bringing the search yield down to 13 citations. A systematic review of manual therapies for cervicogenic headache6 published in 2012 was chosen because, of the 13 citations, it was most pertinent to our PICO question. However, because the systematic review did not contain studies directly comparing manual therapy to NSAIDs, we conducted an additional search using a combination of the key terms, ‘headache’ AND ‘NSAID.’ We filtered this search to systematic reviews and studies published between 2004 and 2021. This search resulted in 103 articles. We added the Boolean operator AND with the term ‘cervicogenic,’ but no additional articles were found. Therefore, the term ‘migraine’ was combined with ‘headache’ (in parentheses) and connected using the Boolean operator OR, and we removed the term ‘NSAID’ from our search string, replacing it with the term ‘Ibuprofen.’ Because this search resulted in a large number of citations involving studies of children, the term ‘children’ was added and connected to our search string using the Boolean operator NOT. This resulted in 19 citations. A systematic review of lowdose Ibuprofen for the treatment of acute migraines7 was chosen because the other results either did not focus on headache conditions that were similar to cervicogenic headache (e.g., cluster, tension), or they involved post-operative pain management. The systematic review also focused on an NSAID that the patient was taking to relieve pain from a headache condition. The entire literature search, including retrieval of manuscripts, took less than 30 minutes.

Both systematic reviews retrieved showed evidence of reduced headache pain using manipulation or Ibuprofen. However, before these results could be applied to the current patient, both systematic reviews were first appraised using a template provided by the Critical Appraisal Skills Program (CASP).8 Specifically, the papers were appraised with respect to their (i) validity, (ii) importance, and (iii) applicability to the treatment of cervicogenic headaches in the current patient.

Both articles by Chiabi and Russell(6) and Suthisisang et al.(7) were systematic reviews that included patients with cervicogenic or migraine headache diagnoses and who had received an intervention. Both included a methods section that described searching multiple databases and finding relevant randomized controlled trials, which are the most appropriate study design for evaluating interventions. However, Chiabi and Russell(6) only evaluated studies that were written in English while Suthisisang et al.(7) did not have any language restrictions, thereby reducing the potential for selection bias. Both reviews also assessed the quality of included articles using validated appraisal tools. In both reviews, the results of all included studies were clearly displayed in evidence tables or in a forest plot. Due to clinical heterogeneity however, the results were not combined in the Chiabi and Russell(6) review, whereas they were combined in the Suthisisang et al.(7) review using a meta-analysis. Therefore, based on the above criteria, the results of both reviews were deemed valid.

The results were deemed important for 2 main reasons. First, in 5 out of 6 manual therapy trials in the Chiabi and Russell review patients receiving cervical SMT, on average, experienced statistically (p < 0.05) and/or clinically significant within-group improvements in headache symptoms (i.e., pain, duration and/or frequency) from baseline to last follow-up. In terms of statistical significance, this means that the probability the observed differences or outcomes occurred by pure chance was less than 5%. The follow-up periods in the included studies ranged anywhere from immediately post-treatment up to 12 months after. In 4 of these 5 studies, there were statistically and/or clinically significant between-group differences as well, favouring the SMT group. In fact, the magnitude of clinical improvements across these studies ranged anywhere from approximately 5% to greater than 50%. [A change of 30% or greater is generally considered to be a clinically meaningful improvement for patients with painful musculoskeletal conditions. (9)] In other words, across these 4 studies, patients were consistently reporting a decrease in headache symptoms after receiving SMT, and in many cases by a clinically meaningful amount, while patients in the placebo or control groups were not reporting similar findings. The only study that did not show any statistically or clinically significant improvements among SMT patients involved cervical SMT that was performed by medical physicians rather than chiropractors, and this may have attenuated the outcome.

Second, the pooled results in the Suthisisang et al. review(7) showed that patients taking Ibuprofen (400 mg) experienced statistically and clinically significant reductions in headache pain within 2 hours compared to placebo. The risk ratios (RRs) for Ibuprofen (400 mg) showed patients on average were 89% more likely to have pain relief (i.e., pain intensity that reduced from severe or moderate down to mild or none) after 2 hours (RR = 1.89; 95% confidence interval [CI], 1.45 to 2.46) and greater than twice as likely to be pain-free at 2 hours (RR = 2.15; 95% CI, 1.24 to 3.73). Extrapolating these findings to the general population, we can be 95% confident that had the total population of acute migraine patients been included in this systematic review, headache sufferers would be between 45% and nearly 2.5 times more likely to have pain relief, or between 24% and 3.7 times more likely to have been pain-free, within 2 hours of taking Ibuprofen (400 mg) as opposed to taking a placebo. The RR for sustained pain-relief (i.e., headache relief beyond 24 hours) was even higher, but not statistically significant because its 95% CI range included the value of 1.0, which in this case equates to no difference (RR = 3.26; 95% CI, 0.48 to 22.08). This demonstrated that not every patient in these studies was able to stop the headaches from reoccurring long-term with Ibuprofen (400 mg). However, some patients did achieve clinically significant sustained pain-relief, as evidenced by the wide CI range that included values of 30% or greater. Therefore, both systematic reviews showed statistically and/or clinically significant improvements in headache symptoms or frequency with their interventions.

(iii) Are the valid, important results of these systematic reviews applicable to this patient?

In the Chiabi and Russell review(6), cervical SMT was performed in 5 of the 6 studies on adults (age 18 or older) who had not received manipulative therapy in the last 12 months and had suffered from cervicogenic headache, as diagnosed according to Cervicogenic Headache International Study Group (CHISG) criteria. Therefore, the age and symptomatology of patients in these 5 studies were similar to the age and headache symptomatology of our patient. In Suthisisang et al.(7), all study participants were 16 years of age or older and suffered from migraine attacks, an analogous headache condition with similar symptomatology to cervicogenic headache. Therefore, because of their clinical commonality, we can assume that the evidence of effectiveness of Ibuprofen on migraines likely provides evidence of effectiveness of NSAIDs on cervicogenic headaches. As such, the results from the 2 systematic reviews were deemed applicable to our patient.

Had this case report been written for the purposes of managing an actual patient, we would have told our patient that, based on research evidence from over 3,500 patients(7), taking 400 mg of Ibuprofen will result in between a 45% and 2.5-fold greater likelihood of getting pain relief, or between a 24% and 3.7-fold greater likelihood of being pain-free, within 2 hours compared to taking a placebo. There is also potential for sustained relief of their headaches beyond 24 hours (i.e., up to over 22 times as likely), but there is also a chance their headaches will reoccur within 24 hours if they do not continue to take Ibuprofen (i.e., 52% increased risk of recurrence). Therefore, there is a good likelihood of at least temporary and clinically significant pain relief with Ibuprofen for headache symptoms, whether that be for pain intensity or headache duration. However, this patient is worried about the potential risks or complications of NSAID use during pregnancy.

In our review of Chiabi and Russell (6) data from 4 studies of nearly 400 patients showed the following: (1) cervical SMT resulted in a 50% decrease in pain for between 47% and 71% of cases, while 33% had complete resolution of pain symptoms; (2) by 4-week follow-up, the duration of cervicogenic headaches decreased in 60% of those treated, and 53% still had a decrease in headache duration after 12 weeks; and (3) the intensity of headaches decreased in 36% to 58% of patients by 4 weeks, with 56% having a decrease in headache frequency as well. Therefore, because SMT has the potential to provide patients with clinically meaningful pain relief – although with less certainty or magnitude than that of Ibuprofen (400 mg) – including in some cases, sustained effects (i.e., weeks of positive benefits versus hours), we would have recommended that this patient consider a trial of chiropractic care, as there is good potential it could give her pain relief and decreased headache frequency without the use of NSAID medications. For instance, the findings of Chiabi and Russell(6) also demonstrated that in 1 study of 200 patients, the consumption of NSAIDs was significantly reduced from pre-treatment to post-treatment (i.e., 93% of patients had a reduced median medication intake after 12 months in the study).

In this case, a 28-year-old woman presented with signs and symptoms suggestive of cervicogenic headache while pregnant. By using the results of 2 systematic reviews, in combination with the patient’s values and clinical circumstances, we deemed that cervical SMT was the preferred treatment option over anti-inflammatory medication. Our report illustrates how research literature can be used in clinical practice, particularly for helping to inform the management of an individual patient.

JULIA CHATIGNY-BLAIS was a 3rd-year chiropractic student at D’Youville College in Buffalo, New York. This case report is published posthumously in her honour.

DR. PETER EMARY is a chiropractor at the Langs Community Health Centre in Cambridge, Ontario. He is a PhD candidate at McMaster University, and he also teaches in the Chiropractic Department at D’Youville College.