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Wet needling of myofascial trigger points in abdominal muscles for treatment of primary dysmenorrhoea
  1. Qiang-Min Huang,
  2. Lin Liu
  1. Department of Sport Medicine, The Center of Rehabilitation, School of Sport Science, Shanghai University of Sport, Shanghai, China
  1. Correspondence to Professor Qiang-Min Huang, Department of Sport Medicine, The Center of Rehabilitation, School of Sport Science, Shanghai University of Sport, Keyanlou 4-408, Hengren Road No. 200, Shanghai 200438, China; huaqia404{at}aliyun.com

Abstract

Objectives To evaluate the effect of wet needling (related to acupuncture) and home stretching exercises on myofascial trigger points (MTrPs) in abdominal muscles for the treatment of dysmenorrhoea.

Methods The effect of wet needing of MTrPs in abdominal muscles, supplemented by home stretching exercises, was observed in 65 patients with moderate and severe primary dysmenorrhoea. The MTrPs in the abdominal region were localised and repeatedly needled with lidocaine injection. Menstrual pain was evaluated with a Visual Analogue Scale (VAS) score after every treatment, with the final evaluation made at a 1-year follow-up. Treatment was stopped when the VAS pain score reduced to ≤3. Symptoms scores were analysed with one-way analysis of variance.

Results The mean VAS pain score before treatment was 7.49±1.16. After a single wet needling session, 41 patients had a reduction in their VAS pain score to <3 during their following menstrual cycle, with a mean of 1.63±0.49. Twenty-four patients who needed two treatments showed a reduction in menstrual pain scores to 0.58±0.50. After 1 year, the mean VAS pain score among all patients was 0.28±0.45, with a response rate of 100%.

Conclusions Primary dysmenorrhoea was significantly reduced 1 year after wet needling to MTrPs in the abdominal region and home stretching exercises, justifying further research with controlled trials.

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Introduction

Primary dysmenorrhoea is a common condition among young women and is characterised by distressing pain and cramping in the lower abdomen during menstruation,1 ,2 often reducing their quality of life. Some have mild pain or discomfort that they find manageable, but many women have moderate or severe pain concentrated in the lower abdomen which negatively affects their physical and mental well-being and is often accompanied by nausea and vomiting, stomach pain, breast tenderness, anal swelling and diarrhoea.1–3

The symptoms of dysmenorrhoea occur before, during and after menstruation. After childbirth, most women no longer experience dysmenorrhoea.4 However, some patients will have a more extreme type of dysmenorrhoea where the pain occurs in the abdomen and also in the head, neck, lower back, pelvis and thighs. Even after childbirth, some women continue to have dysmenorrhoea,4 and, this group of patients is considered to have myofascial pain syndrome, which has been treated according to the principles of myofascial trigger points (MTrPs). This led us to consider whether the pain of primary dysmenorrhoea might be caused by MTrPs in the lower abdominal region and respond to treatment.

MTrPs are a primary source of local neuromusculoskeletal pain, defined as ‘hyperirritable points located in taut bands of skeletal muscle’.5 ,6 When compressed, a referred pain and a recognised pain are characteristic of MTrPs.5 ,7 MTrPs often develop after injury to muscle tissue and are commonly seen in acute and chronic pain conditions and also in orthopaedic conditions.8 ,9 Acute pain is often found in exercise or sports’ participants owing to active MTrPs.10 Chronic pain with MTrPs has been responsible for pain in people with hip osteoarthritis,11 cervical disc lesions,12 temporomandibular dysfunction,13 pelvic pain,14 headaches15 and epicondylitis.16 It has been concluded that myofascial pain syndrome is the most commonly missed diagnosis in subjects with chronic pain.17

Acupuncture treatment has been used in different forms, including wet and dry needling, based on various theories, insights and hypotheses.

We can find no published reports of the use of MTrP principles to treat MTrPs in the abdominal region as the source of primary dysmenorrhoea pain. Therefore, we embarked on this 5-year study in 2007 and here report and summarise this work.

Methods

From 2007 to 2013, a total of 65 patients with primary dysmenorrhoea and with an abdominal Visual Analogue Pain (VAS) pain score of >3 (35 moderate, with VAS score between 4 and 7; and 30 severe, with a VAS score between 8 and 10) received treatment in our clinic and are included in this report. Patients with mild pain (VAS pain score <3) were treated with abdominal muscle stretching or other approaches in our routine clinical work and are not reported. Patients with other diseases and conditions of the reproductive and urinary systems, as well as endometriosis, were excluded. Two-thirds of the subjects were students attending our university, with the remaining one-third being outpatients who were introduced by others who had received successful dysmenorrhoea treatment at our university hospital.

The average age of subjects was 22±2.5 years and mean VAS pain scores 7.49±1.16. This study was conducted using a standard clinical approach, therefore, patients needed to give consent only for receiving invasive treatment. This project was approved for publication by the institutional ethical board of Shanghai University of Sport.

The MTrPs in abdominal muscles were examined and localised according to the three diagnostic criteria from Simons et al7 ,18 and clinical experience. Painful taut bands were palpated in some abdominal muscles. In some patients, palpation caused pain but taut bands could not be identified. Pain on palpation could sometimes be aggravated while balling the abdominal wall, in which case we assumed the presence of MTrP. The locations of MTrPs found in the abdominal wall are roughly as shown in figure 1.

Figure 1

A typical location pattern of trigger points for primary dysmenorrhoea in abdominal muscles from one patient: eight points on the rectus abdominus and four on the ventrolateral muscles.

The skin of the sites was marked and sterilised and the site repeatedly punctured with a 0.4 mm (diameter) hypodermic needle connected to a 5 mL syringe containing 1% lidocaine. During the puncturing process, local muscle jumps (local twitch response) could be elicited once, twice or more, often accompanied by soreness or swelling, and two to three drops of lidocaine were injected to avoid persistent pain. The treatment was carried out in the 2 weeks before menstruation.

During the treatment, the patients were also coached on abdominal muscle self-stretching exercises for self-management (figure 2). Patients were instructed to carry out these exercises three to five times a day, maintaining a static stretching position for 0.5–1 min for each exercise. Further treatment was given according to the VAS pain score for dysmenorrhoea during subsequent menstruations. If the VAS pain score fell to <3 without other symptoms, such as nausea and vomiting, stomach pain, breast tenderness, anal swelling, diarrhoea, etc, the needling treatment was stopped. However, these patients were told to continue doing their abdominal muscle self-stretching exercises (figure 2).

Figure 2

Illustration of self-stretching exercises of abdominal muscles for a supplementary treatment of primary dysmenorrhea. (A) Stretching for the abdominal rectus and internal oblique muscles; (B) stretching for external oblique and internal oblique muscles.

Follow-ups were conducted either over the telephone or by face-to-face clinical interviews 1 year after the last treatment. Pain, symptoms and lifestyle information were reviewed and recorded. The data from each patient were evaluated by a clinical assistant. Mean VAS pain scores and SD were calculated after each treatment and at the final follow-up. Analysis of variance and independent t tests were used for analysis of significant difference, p<0.01.

Results

All patients underwent treatment according to the sites marked by localisation of MTrPs. After the first treatment, 41 patients had VAS score <3, with a mean of 1.63±0.49 (figure 3). In all cases, any associated symptoms were reported as mild. The remaining 24 subjects had a VAS score of ≥3, with a mean of 5.58±0.50 (figure 3) and minimal alleviation in associated symptoms.

Figure 3

VAS scores before and after treatments and at the 1 year follow-up. The dashed line indicates termination of the wet needling treatment for VAS scores <3. The average VAS scores were significantly different before and after each treatment, p<0.0001 and between the second treatment and the 1-year follow-up, p<0.01.

Thus, a single wet needle treatment was effective in 63% of cases. The remaining 24 patients received a second wet needling treatment after relocalisation of MTrPs in the abdominal wall. Subsequent evaluation showed a mean VAS pain score during menstruation of 0.58±0.50 (figure 3), with associated symptoms reported as mild, indicating that needling treatment was no longer needed.

At the 1-year follow-up, all participants provided data and the mean VAS score was 0.28±0.45. Furthermore, the associated symptoms of most patients had disappeared almost entirely (figure 3). Although some patients occasionally had mild pain under certain circumstances, such as when eating cold foods and fruits during menstruation, they were able to control the pain through abdominal muscle self-stretching exercises. The reduction in VAS pain scores from baseline to 1 year for all patients after wet needling treatment was highly significant (p<0.0001). Moreover, for those requiring a second treatment, there was a highly significant decrease (p<0.001) between the first and second treatments (figure 3). The differences in VAS pain scores were also highly significant (p<0.01) between subjects’ last needling treatment and their 1-year follow-up (figure 3). One hundred per cent of subjects had VAS pain scores <3 by the time of their 1-year follow-up evaluation.

Discussion

We found that treatment of primary dysmenorrhoea with wet needling to MTrPs in abdominal muscles, together with abdominal self-stretching exercises, demonstrates 100% effectiveness after one or two treatments.

MTrPs are a highly sensitive loci in the skeletal muscles, which may be latent or active.7 ,18 At the site of MTrPs, a high frequency of spontaneous electrical activity and a concentration of contracture knots can be seen.19 MTrPs in trunk muscles can often affect the function of adjacent internal organs, particularly muscles in the abdomen, chest and pelvic floor.1 Direct treatment of the lower abdominal muscles can relieve the pain in the lower abdominal region, but seems unable to reduce associated symptoms such as nausea, vomiting and tightness in the chest. In our experience, by extending the scope of treatments to the upper and middle parts as well as sides of the abdominal region, these symptoms can also be alleviated, suggesting that they arise from MTrPs in the abdominal muscles. We find that one or two treatments are sufficient to reduce the pain of primary dysmenorrhoea to a VAS score <3. Furthermore, self-stretching of abdominal muscles can be helpful to relieve any remaining discomfort in the abdominal region.

Theoretically, muscle stretching can inactivate MTrPs7 and relieve muscle pain.20 However, this stretching is unlikely to have a substantial effect on its own and is used to consolidate treatment with needling.7 Although the two stretching positions look simple, they are useful for patients to self-manage their abdominal pain and discomfort.

Conventionally, the best known single cause for primary dysmenorrhoea is a high plasma level of prostaglandin produced by the endometrium.21 ,22 Since wet needling treatment can inactivate MTrPs, we speculate that a high plasma level of prostaglandin may trigger activation of latent MTrPs. After menstruation, the concentration of prostaglandin in the blood decreases to normal, the activated MTrPs become latent and pain is relieved. This hypothesis requires further research.19

In this study, conclusions about the effectiveness of acupuncture are limited by the absence of a control group, lack of unblinded assessment and combination with self-exercise.

Conclusion

Primary dysmenorrhoea pain was significantly improved after treatment of MTrPs in abdominal muscles with acupuncture and abdominal stretching exercises. At 1 year, the effectiveness was 100%. Furthermore, all associated symptoms of primary dysmenorrhoea were reduced or disappeared. This result demonstrates that an approach focusing on MTrPs in abdominal muscles may provide long-term relief of abdominal pain and associated symptoms from primary dysmenorrhoea. Further research with controlled trials is justified.

References

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Footnotes

  • Contributors Q-MH and LL summarised their work in the clinic during the years 2007–2013 and wrote the manuscript.

  • Funding This paper is supported by Key Laboratory of Exercise and Health Sciences (Shanghai University of Sport), Ministry of Education and by the provincial open fund of the Sports University of Shanghai.

  • Competing interests None.

  • Patient consent Obtained.

  • Ethics approval Shanghai University of Sport.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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