TY - JOUR
T1 - Pressure-induced referred pain is expanded by persistent soreness
AU - Doménech-García, Victor
AU - Palsson, Thorvaldur S.
AU - Herrero, P.
AU - Graven-Nielsen, Thomas
N1 - DNRF121
PY - 2016
Y1 - 2016
N2 - Several chronic pain conditions are accompanied with enlarged referred pain areas. This study investigated a novel method for assessing referred pain. In 20 healthy subjects pressure pain thresholds (PPTs) were recorded and pressure stimuli (120%PPT) were applied bilaterally for 5-s and 60-s at the infraspinatus muscle to induce local and referred pain. Moreover, PPTs were measured bilaterally at the shoulder, neck and leg before, during and after hypertonic saline-induced referred pain in the dominant infraspinatus muscle. The pressure and saline-induced pain areas were assessed on drawings. Subsequently, delayed onset muscle soreness (DOMS) was induced using eccentric exercise of the dominant infraspinatus muscle. The Day-1 assessments were repeated the following day (Day-2). Suprathreshold pressure stimulations and saline injections into the infraspinatus muscle caused referred pain to the frontal aspect of the shoulder/arm in all subjects. The 60-s pressure stimulation caused larger referred pain areas compared with the 5-s stimulation (P<0.01). Compared with pressure stimulation, the saline-induced referred pain area was larger (P<0.02). After saline-induced pain, the PPTs at the infraspinatus and supraspinatus muscles were reduced (P<0.05) and the 5-s pressure-induced referred pain area was larger than baseline. PPTs at the infraspinatus and supraspinatus muscles were reduced at Day-2 in the DOMS side (P<0.05). Compared with Day-1, larger pressure and saline-induced referred pain areas were observed on Day-2 (P<0.05). Referred pain to the shoulder/arm was consistently induced and enlarged after one day of muscle soreness indicating that the referred pain area may be a sensitive biomarker for sensitization of the pain system.
AB - Several chronic pain conditions are accompanied with enlarged referred pain areas. This study investigated a novel method for assessing referred pain. In 20 healthy subjects pressure pain thresholds (PPTs) were recorded and pressure stimuli (120%PPT) were applied bilaterally for 5-s and 60-s at the infraspinatus muscle to induce local and referred pain. Moreover, PPTs were measured bilaterally at the shoulder, neck and leg before, during and after hypertonic saline-induced referred pain in the dominant infraspinatus muscle. The pressure and saline-induced pain areas were assessed on drawings. Subsequently, delayed onset muscle soreness (DOMS) was induced using eccentric exercise of the dominant infraspinatus muscle. The Day-1 assessments were repeated the following day (Day-2). Suprathreshold pressure stimulations and saline injections into the infraspinatus muscle caused referred pain to the frontal aspect of the shoulder/arm in all subjects. The 60-s pressure stimulation caused larger referred pain areas compared with the 5-s stimulation (P<0.01). Compared with pressure stimulation, the saline-induced referred pain area was larger (P<0.02). After saline-induced pain, the PPTs at the infraspinatus and supraspinatus muscles were reduced (P<0.05) and the 5-s pressure-induced referred pain area was larger than baseline. PPTs at the infraspinatus and supraspinatus muscles were reduced at Day-2 in the DOMS side (P<0.05). Compared with Day-1, larger pressure and saline-induced referred pain areas were observed on Day-2 (P<0.05). Referred pain to the shoulder/arm was consistently induced and enlarged after one day of muscle soreness indicating that the referred pain area may be a sensitive biomarker for sensitization of the pain system.
U2 - 10.1097/j.pain.0000000000000497
DO - 10.1097/j.pain.0000000000000497
M3 - Journal article
C2 - 26808146
SN - 0304-3959
VL - 157
SP - 1164
EP - 1172
JO - Pain
JF - Pain
IS - 5
ER -