We propose a blade as a noninjurious nociceptive stimulus modeling sharp mechanical pain and yielding acute pain and hyperalgesia responses with closer proximity to incision-induced pain/hyperalgesia than punctate or blunt pressure mechanical pain models. Twenty-six healthy men and women were investigated to compare a small incision in the left forearm with noninvasive stimuli of different shapes and modalities to the right forearm. The magnitude and time course of incisional and blade-induced pain were assessed by numerical rating scales. Affective vs sensory components of pain experience were differentiated using a pain sensation questionnaire. The magnitude and time course of the axon reflex vasodilator response and of secondary hyperalgesia following a 7-second blade application were assessed. The maximum blade or incisional pain was similar (visual analogue scale [mean ± SD]: 32.9 ± 22.5 [blade] vs 33.6 ± 29.8 [incision]), and both time courses matched closely in the first 10 seconds (paired t test; P = 0.5-1.0), whereas incision but not blade was followed by a second phase of pain, probably related to the tissue injury (decrease to half maximum pain 8 ± 2 vs 33 ± 35 seconds; P < 0.01). Affective pain scores were significantly lower than sensory scores for all stimuli (P < 0.001). Comparing blade and incision, patterns of affective and sensory pain descriptors exhibited a remarkably similar pattern. Hence, we suggest the blade as novel model of sharp mechanical pain, which will be useful in investigating postoperative/mechanical pain and the role of self-injurious behavior in, eg, patients with borderline personality disorder.
The “blade” is a noninvasive surrogate model that imitates the acute phase of sharp incision-like pain. This model is useful to study mechanisms of mechanical pain and self-injurious behavior.
aDepartment of Neurophysiology, Centre of Biomedicine and Medical Technology Mannheim, Medical Faculty Mannheim, Ruprecht Karls-University Heidelberg, Mannheim, Germany
bDepartment of Psychosomatic Medicine and Psychotherapy, Central Institute of Mental Health, Mannheim, Germany
Corresponding author. Address: Department of Neurophysiology, Centre of Biomedicine and Medical Technology Mannheim (CBTM), Medical Faculty Mannheim, Ruprecht Karls-University Heidelberg, Mannheim, Germany. Tel.: +49-621-383-9934; fax: +49-621-383-9921. E-mail address: email@example.com (U. Baumgärtner).
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Received March 09, 2015
Received in revised form July 24, 2015
Accepted August 31, 2015