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Dopp N, Emary P. MANIPULATION, SOFT-TISSUE THERAPY, OR NO TREATMENT FOR TENSION-TYPE HEADACHE? AN ILLUSTRATIVE EVIDENCE-BASED CASE REPORT. JCC. 2025;8(1):61-67.

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Abstract

Objective

To demonstrate how research findings can inform the management of an individual patient with tension-type headache (TTH).

Clinical Features

A 41-year-old female presented with signs and symptoms consistent with TTH.

Discussion

PubMed was searched for systematic reviews and randomized controlled trials (RCTs) on the effectiveness of chiropractic spinal manipulation in treating TTH. One relevant RCT involving 84 participants with TTH was found and appraised for its validity, importance, and applicability to the management of our specific case. Based on the appraised research evidence, we deemed that a combination of manipulation and soft-tissue mobilization would be more effective than manipulation alone at reducing headache frequency, intensity, and pain perception compared to no treatment. In our patient scenario, we would recommend a 4-week trial (of at least 1 session per week) of soft-tissue therapy and manipulation supported by work- and home-based postural and aerobic exercises.

Conclusion

Evidence from a 2014 RCT published in the chiropractic literature was used in combination with our clinical expertise and patient’s values in formulating a management plan for an individual case of TTH.

INTRODUCTION

Tension-type headaches (TTHs) are the most prevalent neurological disorder worldwide.1 Commonly described as “recurrent” headaches, TTHs typically present with a mild-to-moderate intensity with a pressing/tightening quality around the skull. TTHs are often referred to as muscle contraction, stress, or psychogenic headaches.2 These headaches can be classified as either episodic or chronic. Episodic TTHs are divided into an infrequent type, with headache episodes occurring less than once per month, and a frequent type, with episodes occurring multiple times per month.2 Chronic TTHs are a more severe form of frequent episodic TTH, with headache episodes occurring on 15 or more days per month, on average, for more than 3 months.2

The underlying etiology of TTHs remains uncertain, although peripheral and central pain mechanisms are likely to play a role.2 The most significant abnormal finding commonly seen in patients with TTHs is peri-cranial tenderness. The pain location of a TTH is found to be bilateral in 90% of patients.3 The diagnosis of TTHs is solely established through clinical examination. Therefore, a comprehensive history and exam are necessary as there are no laboratory biomarkers or pathognomonic imaging to confirm the diagnosis.

Our report examines literature supporting the management of TTHs using spinal manipulation in a case scenario involving a 41-year-old woman.

CASE REPORT

(Note: This case report was written as part of a third-year chiropractic course, Evidence-Informed Chiropractic Practice, at D’Youville University. As such, the report herein was based on a patient scenario rather than an actual patient.)

Patient History

A 41-year-old female had a headache of 3 days duration. She described the headache as a “dull, squeezing ache” and rated the severity as a 4 out of 10. She claimed to have had similar and, at times, more intense headaches in the past. Her current headaches have been recurrent; however, these are usually relieved with over-the-counter (OTC) acetaminophen (Tylenol). The patient is seeking chiropractic care as an alternative pain management strategy to reduce her intake of analgesics.

During the history, she located the present headache in the muscles at the back of her skull. She reported that when she would bend over, the pain would refer to the top of her head, accompanied by a radiating pain that was felt on the sides of her skull. Tenderness was elicited over the temple region bilaterally when digital pressure was applied. She noted an increased frequency of headaches over the past 6 months, which she attributed to physical and emotional stress from sitting for long hours at work and managing young children at home. When questioned about the frequency of her headaches, she reported that she was currently experiencing them once a week. She denied any visual auras, photophobia, or phonophobia.

Exam

Range of motion (ROM) testing of the cervical spine was within normal limits. Orthopedic tests including cervical compression, Jackson’s, Soto-Hall, shoulder depression, and cervical distraction were negative, with significant other findings of suboccipital and cervicothoracic tension with the Soto-Hall and shoulder depression tests. Palpation revealed myofascial trigger points in the suboccipital, temporal, and upper trapezius muscles, bilaterally. There was also tenderness to palpation at the right and left occipitoatlantal and atlantoaxial facet joints. Neurological testing, including cranial nerve, upper extremity motor, reflex, and sensory, were unremarkable. Blood pressure and heart rate were within normal at 110/62 mmHg and 60 bpm, respectively. Other than taking OTC analgesics on a regular basis for her headaches, the patient was in good general health and denied taking prescription medications. Based on the history and examination findings, the working diagnosis was frequent, episodic TTH.2

Clinical Question

In a 41-year-old female suffering from episodic TTHs with radiating pain to the temples and scalp, is cervical spinal manipulation with or without soft-tissue therapy more effective than receiving no treatment in reducing the frequency and intensity of pain associated with TTHs?

Using the mnemonic PICO (i.e., Patient/problem, Intervention, Comparison, and Outcome[s] of interest), this question can be broken down as follows:

P = 41-year-old female with episodic TTHs that radiate to the sides and top of the skull

I = Cervical spinal manipulation with or without soft-tissue therapy

C = No treatment

O = Reduction in the frequency and intensity of headaches

The best evidence to answer a clinical question about therapy is a systematic review of randomized controlled trials (RCTs).4 The second-best type of evidence to answer a clinical question about therapy is a high-quality RCT.4 A thorough search of the English language literature was conducted using the PubMed database. A “broad” therapy filter was selected by utilizing the “clinical queries” tool located in PubMed. The key words ‘tension headache’ were combined with the truncated term ‘chiropr*’ using the Boolean operator ‘AND’. This search yielded 33 results. The timeframe was then limited to the past 10 years, which resulted in 16 studies. Inclusion criteria consisted of systematic reviews and RCTs with a title and abstract relevant to TTHs and chiropractic manipulation. Of the 16 results, two studies were deemed relevant5,6; however, the RCT by Espí-López and Gómez-Conesa6 was most specific to our clinical question. A summary of the eligibility criteria for our literature search is presented in Table 1.

Table 1.Literature search inclusion and exclusion criteria.
Inclusion Exclusion
• Systematic reviews (of RCTs), or standalone RCTs • Non-human studies
• Published in English • Observational designs (e.g., cohort, case-control, cross-sectional, case report or series)
• Published in the last 10 years • Narrative reviews, commentaries, editorials, and non-peer reviewed publications (e.g., conference abstracts)

RCT = randomized controlled trial.

Critical Evaluation of the Evidence

We critically appraised the study by Espí-López and Gómez-Conesa6 using the Critical Appraisal Skills Program (CASP) tool for RCTs.7

(i) Are the results of the RCT by Espí-López and Gómez-Conesa6 valid?

The study by Espí-López and Gómez-Conesa6 was a 2014 RCT that examined the effects of manual and manipulative therapy on patients suffering from TTH. The research team provided a clearly formulated research question (i.e., effectiveness of manual, manipulative, or combined manual and manipulative therapy versus no treatment in reducing headache frequency and intensity among adults with TTH). The randomization methods were appropriate, given the design. The study was a 4 x 3 factorial, double-blinded (i.e., data collector- and outcome assessor-blinded), RCT. Patients were allocated to control and experimental groups using a computer-generated random sequence. This was completed by an independent research assistant who was blinded to treatment allocation. The allocation sequence was also concealed from the two physiotherapists who provided treatment to the experimental groups.

Subjects were placed in 1 of 4 groups: group 1 received soft-tissue manual therapy (i.e., 10 minutes of deep-tissue massage to the suboccipital muscles [6]), group 2 received manipulative therapy (directed at the occipitoatlantal and atlantoaxial articulations [6]), group 3 received a combination of soft-tissue manual and manipulative therapy, and group 4 received no treatment. Participants were assessed prior to treatment, after treatment (4 weeks), and at follow-up (8 weeks). Outcome measures that were assessed included cervical ROM, pain perception, and frequency and intensity of headaches. Cervical ROM was measured using a cervical ROM device with established intra- and inter-rater reliability6 (Appendix 1). Pain perception was evaluated through the McGill Pain Questionnaire (Appendix 2). TTH frequency and intensity were measured with a daily register of headaches (Table 2). Patients were instructed to record TTH frequency (e.g., number of headaches per week) and intensity through a numeric pain scale (0 = no pain, 10 = most severe pain). The necessary sample size to elicit statistically significant results was calculated in the study using the nQuery Advisor software program.6 This resulted in a sample size of 19 subjects per group. Due to the potential for dropouts, eight more subjects were included in the study, resulting in an average of 21 subjects per group. Out of the 84 participants, only 2 dropped out of the manipulation group (group 2), as well as two from the ‘no treatment’ group (group 4), and there were no crossovers between groups.

There was some variability in the baseline characteristics of participants among the four groups. For example, fewer participants in the ‘no treatment’ group reported photophobia or phonophobia at baseline and that physical activity was an aggravating factor with their TTHs compared to the other three groups. In addition, more patients in the soft-tissue manual therapy group (group 1) had nausea or vomiting and peri-cranial tenderness as associated symptoms with their headaches compared to groups 2-4. While no characteristic showed extreme deviation, the abovementioned differences could have introduced bias due to potential confounding. Aside from the experimental interventions, all four groups underwent the same study protocol including a vertebral artery rotation test (bilaterally), followed by a gentle 2-minute neck massage before each treatment session. After each treatment session, treatment groups were instructed to stay in the supine position for 5 minutes.6 All four groups were also assessed using the same outcome measures and timepoints throughout the study.

Table 2.Results from the daily register of headaches among participant groups in the trial (table adapted from Espí-López and Gómez-Conesa6).
Daily headache register Soft-tissue manual therapy Manipulative therapy Combination of manual and manipulative therapy No treatment/ control
Frequency
Week 1 3.25 (2.29) 2.90 (1.86) 3.80 (1.79) 3.24 (1.57)
Week 4 2.60 (2.13) 1.70 (2.00) 1.55 (1.50) 2.45 (1.50)
Week 7 2.45 (2.08) 2.15 (2.25) 1.65 (1.75) 2.85 (1.92)
Week 1-4 t/z t = 1.68; P = 0.10 z = − 2.63; P = 0.008b z = − 3.64; P = 0.000c t = 1.89; P = 0.07
Week 1-7 t/z t = 1.59; P = 0.12 z = − 1.49; P = 0.13 z = − 3.03; P = 0.002b t = 0.55; P = 0.58
Effect size 0.34 0.39 1.15 0.24
Intensity
Week 1 4.79 (2.26) 5.12 (1.95) 4.80 (1.68) 5.24 (1.80)
Week 4 3.77 (2.51) 3.03 (2.80) 3.24 (2.72) 3.95 (2.12)
Week 7 2.82 (2.20) 3.28 (2.39) 3.02 (2.60) 3.86 (2.00)
Week 1-4 t/z t = 1.49; P = 0.15 t = 2.69; P = 0.014a z = − 2.21; P = 0.02a t = 2.34; P = 0.03a
Week 1-7 t/z t = 1.30; P = 0.20 t = 2.86; P = 0.01b z = − 2.42; P = 0.01b t = 2.24; P = 0.03a
Effect size 0.54 0.91 1.01 0.74

All results are presented as mean (SD) unless indicated otherwise.
z, Wilcoxon test; t, t test for 2 related samples.
a ≤ 0.05; b ≤ 0.01; c ≤ 0.001.

(ii) Are the results of the RCT by Espí-López and Gómez-Conesa6 important?

The results were deemed important due to statistically and clinically significant improvements in TTH intensity and frequency among the experimental groups compared to the control group. All three experimental groups showed significant improvements with various dimensions of pain perception, whereas results for cervical ROM were mixed. Although this study did not report risk statistics or confidence intervals, the authors included p-values and effect sizes to support their findings. The threshold for statistical significance was 5% (i.e., p-value ≤ 0.05). Between week 1 and week 7 of the study, the combination group showed a statistically significant within-group reduction in headache frequency (p = 0.002). In absolute terms, this treatment approach reduced the number of headaches by more than half. During this same timeframe, the manipulation and combination groups both showed statistically significant within-group reductions in headache intensity, exceeding the minimally important difference (i.e., the smallest amount of improvement that patients recognize as important).8 P-values in each case were 0.01.

When comparing mean values, effect sizes of 0.2-0.5 are considered small, 0.5-0.8 are medium, and > 0.8 are considered large.6,9 For TTH frequency, the combination group had the largest effect size (1.15), indicating that this treatment approach had the strongest effect on reducing headache frequency compared to the other experimental interventions or to no treatment. Compared to the combination group, the manipulation group had a much smaller effect size (0.39), indicating that manipulation, on its own, had a much weaker (i.e., small) effect on reducing headache frequency. For TTH intensity, the combination group had the largest effect size (1.01) when compared to the other interventions or to no treatment, again indicating that this therapeutic approach had the greatest effect on reducing headache intensity. The manipulation group had a slightly smaller within-group effect size of 0.91. This indicates that, although lower than the combination group, manipulation still had a large (and therefore, clinically significant [9]) effect on reducing headache intensity among participants. Manipulation and combined soft-tissue therapy and manipulation also had moderate-to-large effects on the affective, evaluative, and pain intensity dimensions of TTHs among participants, as measured via the McGill Pain Questionnaire (see Appendix 2). The effects of ‘no treatment’ on these outcomes ranged from very small (or negligible) to moderate.

(iii) Are the valid, important results of the RCT by Espí-López and Gómez-Conesa6 applicable to our patient?

The inclusion and exclusion criteria from the article by Espí-López and Gómez-Conesa6 are outlined in Table 3. Of the nine inclusion criteria provided, our patient aligned with 8 (i.e., she was between the ages of 18-65, diagnosed with frequent episodic TTH, had episodes on more than one day per month, experienced headache episodes lasting from 30 minutes to 7 days, had bilateral location of pain with a “pressing” quality and mild-to-moderate intensity, peri-cranial tenderness, was suffering from TTHs for more than 3 months, and was under pharmacological control).6 Of the exclusion criteria, our patient aligned with 2 of the 15 (i.e., increased emotional tension, and headaches that were aggravated by head movement).6 Our patient reported being under excessive amounts of stress due to work and having young children at home. Although she was able to locate the pain in the muscles in the back of her neck and sides of her head (i.e., suboccipital and temporalis muscles), she explained that bending over caused her headache pain to refer to the top of her head. Despite meeting these two exclusion criteria, it can be argued that meeting most (89%) of the inclusion criteria and few (13%) of the exclusion criteria and having the potential for positive treatment outcomes with soft-tissue and manipulative therapy would outweigh these exclusions. As such, we feel this evidence is applicable to our patient.

Table 3.Participant eligibility criteria (table adapted from Espí-López and Gómez-Conesa6).
Inclusion criteria Exclusion criteria
• Subjects aged between 18 and 65 years* • Patients with infrequent episodic TTH, and patients with probable TTH in its frequent and infrequent forms
• Diagnosis of frequent episodic TTH or chronic TTH* • Headache that is aggravated by head movements*
• Having headache episodes on more than 1 day/month* • Metabolic or musculoskeletal disorders with symptoms similar to headache
• Headache episodes lasting from 30 minutes to 7 days* • Previous neck trauma
• Headaches having at least 2 of the following characteristics: • Vertigo, dizziness, arterial hypertension
-Bilateral location of pain* • Joint stiffness, arteriosclerosis, or advanced degenerative osteoarthritis
-Pressing non-pulsating quality* • Patients with heart devices
-Mild or moderate intensity* • Patients in process of pharmacological adaptation
-Not aggravated by physical activity • Excessive emotional tension*
• Sufferers may present with photophobia, phonophobia, nausea, or vomiting • Neurological disorders
• Headache may be associated with peri-cranial tenderness* • Laxity of neck soft tissues
• Suffering from TTH for over 3 months* • Radiological alterations
• Subjects being under pharmacological control* • General hypermobility or hyperlaxity
• Joint instability
• Pregnancy

TTH = tension-type headache.
* Inclusion and exclusion criteria met by our patient.

Application of the Evidence

In the article by Espí-López and Gómez-Conesa,6 cervical spine manipulation resulted in a statistically significant improvement in headache intensity with a large effect size (0.91) at 8-week follow-up. It was also found that the combination of soft-tissue mobilization to the suboccipital muscles along with cervical spine manipulation showed statistically significant improvements in headache intensity and frequency at 8-week follow-up, with even larger effect sizes (1.01 and 1.15, respectively). There were also significant improvements (with effect sizes as large as 1.60) involving pain perception (i.e., affective, evaluative, and pain intensity dimensions) with manipulation or combined soft-tissue therapy and manipulation,6 particularly when compared to having no treatment. Based on these findings, which we deemed to be valid, important and applicable to our patient, it can be concluded that manipulation and/or a combination of soft-tissue manual therapy and manipulation are more effective than no treatment in reducing TTH frequency and intensity, as well as with improving certain aspects of pain perception. The effect sizes for these outcomes with no treatment were either very small-to-small (range, 0.18-0.33) or moderate (range, 0.61-0.74).6 Therefore, for the best results, we would recommend that our patient receive a combination of cervical spine manipulation and soft-tissue manual therapy to reduce the intensity, frequency, and self-perceived disability of her headaches. We would recommend a 4-week trial (of at least 1 session per week), supported by work- and home-based postural and aerobic exercises.10

Evaluation of the Outcome

Based on the evidence presented in the RCT by Espí-López and Gómez-Conesa,6 cervical spine manipulation was found to be effective in reducing TTH intensity and improving pain perception. However, a combination of soft-tissue manual and manipulative therapy would likely provide greater improvements in the intensity, frequency, and pain perception of our patient’s headaches. It can be speculated that if our patient underwent this specific combination of treatments, she would score significantly better on follow-up outcome measures such as characteristics of headaches, pain perception, and the daily register (i.e., frequency and intensity) of headaches. If our patient had not been informed of the results from this study or did not undergo chiropractic care, the intensity of her headaches may still have moderately improved (given the natural history of the disorder); however, the findings from this RCT suggest that the frequency of her headaches would not have improved (i.e., p-values of 0.07 and 0.58 at 4- and 8-week follow-up, respectively).6 Moreover, her negative quality of life, emotional tension, and intake of analgesics may have persisted or increased due to the frequency and intensity of pain associated with TTHs, in association with her ongoing lifestyle factors.

Limitations

The limitations of our report largely pertain to a lack of evidence regarding chiropractic treatment for TTHs. The available evidence that included recent information on chiropractic care and TTHs was limited to two articles5,6 after searching the PubMed database. Moreover, the study we chose included manipulation performed by physical therapists rather than by chiropractors. In addition, the therapists and participants were not blinded to the interventions, which, when combined with the use of subjective outcome measures,6 may have biased the results. As such, this RCT would be graded as moderate- or low-quality evidence because of serious indirectness and/or risk of bias.11 Another limitation was that our literature search included only a single database. A more in-depth search of the evidence, including multiple databases (e.g., DynaMed, Google Scholar), may have yielded more studies. Using an RCT instead of a systematic review is also considered a limitation. A systematic review would have been preferred as it ranks higher on the hierarchy of evidence.4 Furthermore, because this report was based on a single RCT, clinicians should note that additional research evidence on the efficacy and effectiveness of manual therapy, including chiropractic spinal manipulation, is necessary to inform the chiropractic management of patients with TTH. In addition, we did not consider evidence on other comparative interventions for TTH (i.e., pharmacologic or non-pharmacologic) in our appraisal. However, previous studies on patients with TTH suggest that a manual therapeutic approach consisting of either spinal manipulation or mobilization, soft-tissue massage and home-based postural exercises is as effective or better than tricyclic anti-depressants or other usual care provided by general physicians (e.g., advice, analgesics, and non-steroidal anti-inflammatory drugs).5,12

CONCLUSION

Through utilization of an evidence-based format,13,14 the purpose of this report was to demonstrate how research can be used to inform the management of an individual patient in clinical practice. In this specific scenario, a 41-year-old woman presented with signs and symptoms indicative of a TTH. After analyzing and applying the results of a relevant RCT, it was determined that a combination of soft-tissue manual therapy and cervical spine manipulation would result in a greater reduction in headache frequency, intensity, and pain perception in our patient compared to manipulation alone, or to no treatment.

Submitted: December 15, 2024 CDT

Accepted: January 23, 2025 CDT

References

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Appendix 1.Results of cervical ROM among participant groups in the trial (table adapted from Espí-López and Gómez-Conesa6).
Cervical ROM Soft-tissue manual therapy Manipulative therapy Combination of manual and manipulative therapy No treatment/ control
Cervical flexion
Pretreatment 49.20 (12.53) 53 (10.23) 53.25 (12.39) 46.95 (9.03)
Posttreatment 59.85 (11.61) 54.95 (9.86) 53.05 (11.24) 50.29 (9.81)
Follow-up 56.85 (10.85) 52.30 (11.24) 52.75 (10.32) 49.40 (9.47)
Pre/Posttreatment z = − 3.04; P = 0.002b z = − 1.22; P = 0.22 z = − 0.41; P = 0.67 z = − 2.40; P = 0.02a
Pre/Follow-up z = − 2.26; P = 0.02a z = − 0.50; P = 0.61 z = − 0.18; P = 0.85 z = − 2.03; P = 0.04a
Effect size 0.59 0.007 0.04 0.26
Cervical extension
Pretreatment 50.90 (14.51) 49.36 (10.36) 53.40 (13.06) 51.82 (11.29)
Posttreatment 57.05 (13.33) 56.35(11.85) 57.80 (14.53) 54.24 (11.44)
Follow-up 54.15 (12.91) 53.50 (7.56) 57.85 (11.49) 55.10 (11.73)
Pre/Posttreatment t = − 2.34; P = 0.03a t = − 2.26; P = 0.03a t = − 1.94; P = 0.06 t = − 1.46; P = 0.15
Pre/Follow-up t = − 0.93; P = 0.36 t = − 1.67; P = 0.10 t = − 1.41; P = 0.17 t = − 1.71; P = 0.10
Effect size 0.21 0.38 0.33 0.28
Right lateral flexion
Pretreatment 35.60 (14.36) 39.50 (6) 39.95 (8.67) 38.32 (6.22)
Posttreatment 38.60 (8.13) 40.10 (10.73) 40.25 (8.06) 40.95 (8.25)
Follow-up 38.05 (7.03) 41.70 (7.37) 39.85 (6.40) 40.70 (5.44)
Pre/Posttreatment t = − 1.03; P = 0.31 t = − 0.43; P = 0.67 t = − 0.17; P = 0.86 t = − 1.55; P = 0.13
Pre/Follow-up t = − 0.86; P = 0.39 t = − 1.26;P = 0.22 t = − 0.05; P = 0.17 t = − 3.31;P = 0.04a
Effect size 0.16 0.35 0.01 0.37
Left lateral flexion
Pretreatment 38.15 (12.69) 39.54 (6.36) 41.45 (9.49) 38.27 (7.08)
Posttreatment 41.35 (7.47) 44.05 (5.59) 41.05 (8.73) 41.14 (6.46)
Follow-up 40.60 (7.70) 42.50 (5.74) 43.20 (6.95) 40.20 (5.81)
Pre/Posttreatment z = − 1.71; P = 0.08 z = − 2.40; P = 0.01b z = − 0.03; P = 0.97 z = − 2.73; P = 0.06
Pre/Follow-up t = − 0.86; P = 0.39 z = − 1.96; P = 0.04a z = − 0.76; P = 0.44 z = − 1.52; P = 0.04a
Effect size 0.19 0.45 0.18 0.40
Right rotation
Pretreatment 59.85 (11.94) 61.05 (8.27) 63.10 (9.76) 58.73 (9.70)
Posttreatment 64.35 (12.28) 68.70 (7.86) 67.95 (9.96) 61.86 (7.67)
Follow-up 61.80 (12.24) 66.45 (7.51) 66.05 (10.84) 60.45 (7.87)
Pre/Posttreatment z = − 2.34; P = 0.02a z = − 3.42; P = 0.000c z = − 2.02; P = 0.04a z = − 1.77; P = 0.07
Pre/Follow-up z = − 0.68; P = 0.49 z = − 2.69; P = 0.007b z = − 1.55; P = 0.12 z = − 0.28; P = 0.77
Effect size 0.16 0.63 0.29 0.17
Left rotation
Pretreatment 56.50 (14.34) 64.45 (8.05) 63.45 (11.26) 62.36 (9.23)
Posttreatment 66.83 (11.22) 64.15 (13.47) 71.50 (7.61) 68.10 (12.12)
Follow-up 63.15 (10.79) 68.20 (9.14) 66.80 (11.76) 61.40 (9.74)
Pre/Posttreatment t =−4.03; P = 0.000c t = − 3.07; P = 0.006b t =−2.40; P = 0.02a t = − 1.06; P = 0.30
Pre/Follow-up t = − 2.59; P = 0.02a t = − 2.33; P = 0.03a t = − 1.51; P = 0.14 t = − 0.89; P = 0.38
Effect size 0.45 0.45 0.29 0.10

ROM = range of motion.
All results are presented as mean (SD) unless indicated otherwise.
z, Wilcoxon test; t, t test for 2 related samples.
a ≤ 0.05; b ≤ 0.01; c ≤ 0.001.

Appendix 2.Results of the McGill Pain Questionnaire among participant groups in the trial (table adapted from Espí-López and Gómez-Conesa6).
McGill Pain Questionnaire Soft-tissue manual therapy Manipulative therapy Combination of manual and manipulative therapy No treatment/ control
Sensory dimension
Pretreatment 19.20 (8.48) 20.81 (10.45) 18.80 (9.76) 20.04 (9.37)
Posttreatment 15.85 (9.44) 15.40 (11.74) 16.20 (8.18) 15.80 (9.49)
Follow-up 13.95 (10.82) 12.70 (10.85) 14.25 (9.19) 13.95 (7.76)
Pre/Posttreatment t = 1.35; P = 0.19 t = 2.38; P = 0.02a t = 1.85; P = 0.07 t = 3.31; P = 0.003b
Pre/Follow-up z = − 2.31; P = 0.02a z = − 3.55; P = 0.000c z = − 2.20; P = 0.02a z = − 2.94; P = 0.003b
Effect size 0.59 0.75 0.45 0.62
Affective dimension
Pretreatment 2.80 (2.41) 2.68 (2.23) 3 (2.24) 2.27 (2.25)
Posttreatment 1.75 (1.58) 1.55 (1.84) 1.85 (1.66) 1.95 (2.10)
Follow-up 2.20 (2.44) 0.90 (1.59) 1.60 (2.19) 1.85 (2.25)
Pre/Posttreatment t = 2.01; P = 0.05a t = 2.06; P = 0.05a t = 2.88; P = 0.01b t = 0.98; P = 0.33
Pre/Follow-up z = − 1.40; P = 0.15 z = − 2.88; P = 0.004b z = − 2.58; P = 0.01b z = − 1.25; P = 0.21
Effect size 0.24 0.77 0.6 0.18
Evaluative dimension
Pretreatment 2.75 (0.91) 2.63 (1.00) 2.65 (0.87) 2.22 (0.97)
Posttreatment 1.80 (1.19) 1.85 (0.98) 2.25 (0.96) (1.76-0.94)
Follow-up 1.90 (0.79) 1.60 (0.99) 2.00 (1.03) 1.90 (0.91)
Pre/Posttreatment t = 2.89; P = 0.009b t = 2.99; P = 0.007b t = 1.71; P = 0.10 t = 4.26; P = 0.000c
Pre/Follow-up z = − 2.85; P = 0.004b z = − 3.37; P = 0.001b z = − 2.29; P = 0.02b z = − 1.73; P = 0.08
Effect size 0.91 1.00 0.71 0.33
Number of word descriptors
Pretreatment 11.25 (4.55) 11.68 (5.03) 10.45 (4.53) 11.09 (4.70)
Posttreatment 8.90 (4.82) 9.25 (5.52) 9.35 (4.68) 9.48 (5.50)
Follow-up 8.10 (4.93) 7.00 (5.06) 7.70 (4.77) 8.80 (4.91)
Pre/Posttreatment t = 1.94; P = 0.06 t = 2.39; P = 0.02a t = 1.78; P = 0.09 t = 2.83; P = 0.10
Pre/Follow-up z = − 2.63; P = 0.008b z = − 3.73; P = 0.000c z = − 2.99; P = 0.003b z = − 2.43; P = 0.47
Effect size 0.66 0.89 0.58 0.47
Intensity of pain
Pretreatment 4.45 (2.11) 4.64 (2.12) 4.85 (2.00) 5.27 (2.22)
Posttreatment 3.45 (2.52) 3.35 (2.25) 2.00 (1.55) 4.24 (2.54)
Follow-up 2.55 (1.82) 2.50 (2.37) 1.50 (1.64) 3.85 (2.35)
Pre/Posttreatment t = 1.96; P = 0.06 t = 2.10; P = 0.04a t = 4.35; P = 0.000c t = 1.70; P = 0.10
Pre/Follow-up t = 4.14; P = 0.001c t = 3.05; P = 0.007b t = 7.77; P = 0.000c t = 2.26; P = 0.03a
Effect size 0.86 0.87 1.60 0.61

All results are presented as mean (SD) unless indicated otherwise.
z, Wilcoxon test; t, t test for 2 related samples.
a ≤ 0.05; b ≤ 0.01; c ≤ 0.001.