Differences in pain perception in women using concentric and monopolar needles.

OBJECTIVE

To examine pain perception using concentric needle electrodes and monopolar needle electrodes in an all-female study group without underlying hand or arm pain complaints, using study subjects as their own controls.

DESIGN

Prospective randomized study. Two muscles--the biceps and abductor pollicis brevis (APB)--were examined using both a concentric needle electrode and a monopolar needle electrode.

SETTING

University community.

PARTICIPANTS

Eighty healthy female employees at the University of Utah and Primary Children's Hospital were enrolled. All completed the study.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Pain scores. Posttest verbal analog pain scale (0-10) measures were obtained after each muscle was studied. A subset of subjects (n=51) was asked to identify needle preference after completion of the study.

RESULTS

There was no significant difference in mean pain scores between the concentric needle electrode and the monopolar needle electrode (3.06 and 3.10, respectively; P=.803). The APB muscle was significantly more painful than the biceps muscle with both needle types (mean pain scores, 3.92 and 2.24, respectively; P<.001). In the subset of subjects asked to identify needle preference after completion of the study, 21 chose a concentric needle electrode and 30 a monopolar needle electrode. This difference was not statistically significant. However, verbal analog pain scores were lower with the needle preferred by each subject (P<.20).

CONCLUSIONS

There is no significant difference in mean pain scores reported between a concentric needle electrode and a monopolar needle electrode. Subjects were clear on the needle they preferred, and the pain scores reported for the less painful needle were lower than those for the other needle.