Referred Pain Patterns of the Infraspinatus Muscle Elicited by Deep Dry Needling and Manual Palpation

Abstract

Objectives: To identify the most common referred pain (ReP) pattern of the infraspinatus myofascial trigger point (MTrP) and compare its coincidence with the original ReP pattern, to verify whether there are any significant differences by sex and types of technique and to determine the observed signs and symptoms evoked by deep dry needling (DDN) and manual palpation (MPal). Design: A cohort study of patients randomized to two different examination methods (July and August 2016). Settings: Students and staff recruited from Miguel Hernandez University (Southeast Spain). Patients: One hundred thirty-three participants (70.7% women) with shoulder complaints were randomly assigned to either an MPal (n = 67) or DDN group (n = 66). Interventions: The same physiotherapist carried out the techniques on all participants, and the same protocol was followed for both the DDN and MPal groups. The physiotherapist did not ask participants about their pain features or other relevant issues. Outcome measures: Local twitch response (LTR) and ReP assessed through a visual analogue scale and features of ReP of the infraspinatus muscle. Results: The areas with the highest percentage of ReP were the front (area 3; 27.1%) and back (area 11; 21.1%) of the arm, anterior (area 4; 36.1%) and posterior (area 12; 42.1%) shoulder, and infraspinatus muscle area. DDN proved to be significantly easier than MPal in evoking an LTR ( p £ 0.001). There were significant differences between sexes in zone 2 ( p = 0.041) and no statistically significant differences were found by technique. Conclusions: The ReP pattern of the infraspinatus muscle coincides with the original pattern described by Travell and Simons, although the neck area should be questioned. The study found no significant differences in the ReP pattern by sex and when comparing MPal with DDN of MTrP of the infraspinatus muscle. DDN proved to be significantly easier than MPal in evoking an LTR