Immediate Effect of Dry Needling on Trigger Points

Immediate Effect of Dry Needling on the Viscoelastic Properties of a Trigger Point on the Infraspinatus Muscle Measured With the MyotonPro

The immediate effects (0-30 minutes) of a dry needling intervention on a trigger point on their viscoelastic properties (tone, elasticity and stiffness)

Objectives: To investigate the immediate effects of a dry needling puncture on the viscoelastic properties (tone, stiffness and elasticity) of a trigger point (TP) located in the infraspinatus muscle in participants with non-traumatic chronic shoulder pain.

Methods: Forty-eight individuals who presented non-traumatic chronic shoulder pain were recruited. The presence of a TP in the infraspinatus muscle of the painful side was confirmed by an experienced physiotherapist with a palpatory exam according to Travell and Simons criteria. The TP was marked and the viscoelastic properties including tone, stiffness and elasticity were measured with the MyotonPro device by an evaluator. After the first set of measurements (T1), an experienced physiotherapist applied a dry needling puncture to the TP with a pistoning technique to obtain a local twitch response (LTR) with an Optimed 40 x 0.30 mm single use acupuncture needle. The same set of measurements was repeated immediately after the dry needling (T2) and 30 minutes later (T3). Repeated measures ANOVA and post-hoc tests were used to assess changes in viscoelastic properties over time with a significant level set at 0.05.

Inclusion Criteria:

1. present with chronic shoulder pain of non-traumatic origin (rated at least 2/10 on a numeric rating scale (NRS) for more than 3 months. The pain had to be located in the shoulder area or referred in the area of the infraspinatus as described by Travell and Simons (1999);
2. have a hyperirritable spot within a palpable tight band that reproduced the participant's pain when compressed by palpation; and
3. have a body mass index (BMI) lower than 28

Exclusion Criteria:

1. diagnosis of capsulitis, cancer, or metastasis;
2. previous shoulder or thorax surgery or a mastectomy;
3. shoulder girdle bone fracture;
4. C4-C5 or C6 radiculopathy;
5. known osteoporotic profile (positive bone densitometry);
6. apparent atrophy of the infraspinatus fossa (visual interpretation) and
7. contraindications to receive a DN intervention