To report the characteristics of myofascial trigger points (MTrPs) in the infraspinatus muscle and evaluate the therapeutic effect of trigger-point injections.
Medical records of 297 patients (221 women; age, 53.9±11.3 years) with MTrPs in the infraspinatus muscle were reviewed retrospectively. Because there were 83 patients with MTrPs in both infraspinatus muscles, the characteristics of total 380 infraspinatus muscles with MTrPs (214 one side, 83 both sides) were investigated. Specific characteristics collected included chief complaint area, referred pain pattern, the number of local twitch responses, and distribution of MTrPs in the muscle. For statistical analysis, the paired t-test was used to compare a visual analogue scale (VAS) before and 2 weeks after the first injection.
The most common chief complaint area of MTrPs in the infraspinatus muscle was the scapular area. The most common pattern of referred pain was the anterolateral aspect of the arm (above the elbow). Active MTrPs were multiple rather than single in the infraspinatus muscle. MTrPs were frequently in the center of the muscle. Trigger-point injection of the infraspinatus muscle significantly decreased the pain intensity. Mean VAS score decreased significantly after the first injection compared to the baseline (7.11 vs. 3.74; p<0.001).
Characteristics of MTrPs and the therapeutic effects of trigger-point injections of the infraspinatus muscle were assessed. These findings could provide clinicians with useful information in diagnosing and treating myofascial pain syndrome of the infraspinatus muscle.
Citations
To assess head posture using cervical spine X-rays to find out whether forward head posture is related to myofascial pain syndrome (MPS) in neck and shoulder.
Eighty-eight participants who were diagnosed with MPS in neck and shoulder were evaluated in this study. Four parameters (distance among head, cervical spines, and shoulder, and cervical angle) were measured from lateral view of cervical spine X-ray. The location and number of trigger points in the neck and shoulder and symptom duration were evaluated for each patient.
Both horizontal distances between C1 vertebral body and C7 spinous process and between the earhole and C7 vertebral body were negatively correlated with cervical angle reflecting cervical lordosis (p<0.05). Younger patients had significantly (p<0.05) less cervical angle with more forward head posture. There was no relationship between MPS (presence, location, and number of trigger points) and radiologic assessments (distance parameters and the cervical angle).
Forward head posture and reduced cervical lordosis were seen more in younger patients with spontaneous neck pain. However, these abnormalities did not correlate with the location or the number of MPS. Further studies are needed to delineate the mechanism of neck pain in patients with forward head posture.
Citations
To investigate the effect of extracorporeal shock wave therapy (ESWT) on myofascial pain syndrome (MPS).
Thirty patients with MPS in trapezius muscle were randomly divided into two groups, ESWT group (n=15), and trigger point injections (TPI)+transcutaneous electrical nerve stimulation (TENS) group (n=15). For a total of 3 weeks, ESWT was undertaken with 1,500 pulse each time at one week interval totaling 4,500 pulse, TPI for once a week totaling three times and TENS for five times a week totaling three weeks.
The changes in pain threshold (lb/cm2) showed the values of 6.86±1.35 before first therapy, 11.43±0.27 after first therapy, and 12.57±0.72 after third therapy, while TPI+TENS group showed the values of 6.20±1.92 before first therapy, 8.80±0.48 after first therapy, and 9.60±2.19 after third therapy, and the changes between the groups were significantly different (p=0.045). The changes in visual analog scale were estimated to be 6.86±0.90 before first therapy, 2.86±0.90 after first therapy, and 1.86±0.69 after third therapy in case of ESWT group, whereas the figures were estimated to be 7.20±1.30 before first therapy, 4.60±0.55 after first therapy, and 2.80±0.84 after third therapy in case of TPI+TENS group, and the changes between the groups were significantly different (p=0.010). The changes in McGill pain questionnaire (p=0.816) and pain rating scale (p=0.644) between the groups were not significantly different. The changes in neck ROM were also not significantly different between the groups (p>0.05).
The ESWT in patients with MPS in trapezius muscle are as effective as TPI and TENS for the purpose of pain relief and improving cervical range of motion.
Citations
Postherpetic neuralgia(PHN) is a common complication of herpes zoster and one of most common intractable conditions in pain clinics. The PHN is defined solely by the persistence of pain after the herpes zoster. There has been no known pathophysiology for the PHN and the role of scars, local muscles, tendons and ligaments has not been addressed.
The characteristics, duration, and location of the referred pain were evaluated along with the electromyographic(EMG) examination of involved muscles. Then treatment was given under the concept of a myofascial pain syndrome till the pain was completely resolved. Most of the patients with acute or chronic pain were relieved from the pain.
This study revealed a practical and important new concept on herpes zoster related pains. In some cases of herpes zoster, acute herpes zoster seems to be an initiating factor to form an acute trigger point in the muscles of the related area. And uncomplicated trigger points neglected in an acute stage become chronic intractable problems, when they were neglected.
In conclusion, myofascial pain syndrome should be taken into account when a postherpetic neuralgia is diagnosed. The recognition of this possible relationship between PHN and myofascial pain syndrome and an early proper care can greatly reduce the suffering of patents from chronic pain.
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