Calibrated Forceps: A Sensitive and Reliable Tool for Pain and Analgesia Studies

Pressure application measurement (PAM): A novel behavioural technique for measuring hypersensitivity in a rat model of joint pain

“…These values are considerably higher than those seen in the paw using calibrated forceps or the Randall and Selitto device (Baamonde et al, 2004;Cook and Moore, 2006;Luis-Delgado et al, 2006;Randall and Selitto, 1957;Walker et al, 2003) which is probably due to the difference in the size and gross anatomy of the paw and the knee joint, in addition, the surface area over which the pressure is applied differs between the different devices. Pressure exerted onto the skin may activate nociceptive afferents in several tissues, depending on the surface area of the object used.…”

“…To that end, PAM was developed to align pre-clinical measures to those used clinically and help the translation of animal studies to human conditions. Calibrated forceps have been used as a means of mechanical stimulation during electrophysiological recording (Gracely et al, 2003;Li and Neugebauer, 2004;Neugebauer and Li, 2002), or to measure knee joint or paw pain in experimental inflammation and primary hyperalgesia induced in deep tissues by inflammation (Han et al, 2005;Luis-Delgado et al, 2006;Yu et al, 2002). The latter involved direct application of the forceps to muscle or to the knee joint of rats (Cui et al, 1999;Skyba et al, 2005).…”

“…The latter involved direct application of the forceps to muscle or to the knee joint of rats (Cui et al, 1999;Skyba et al, 2005). However, although the technique is reported to be an easy to use, reliable method of assessing nociceptive withdrawal thresholds, they also show a steady increase in paw withdrawal threshold over a 9-day period that was highly correlated to an increase in weight gain over this time (Luis-Delgado et al, 2006). The authors suggest that the modification of pain sensitivity was due to increased size of the paw.…”

Von Frey's hairs – a review of their technology and use – a novel automated von Frey device for improved testing for hyperalgesia

“…There are a number of other difficulties with the system including limited ability to apply the hairs to the same spot, vague definitions of "responses", variability of paradigms, movement of sensory surfaces, the logarithmic scale of the measure and the influence of subjectivity (Luis-Delgado et al, 2006;Vrinten and Hamers, 2003).…”

“…Since the rise of the concept of neuropathic pain, researchers have sought to develop improvements to the technique in order to measure neuropathic-induced changes in a repeatable manner. These have included "calibrated forceps" (Luis-Delgado et al, 2006) and "catwalk" gait analysis (Vrinten and Hamers, 2003). The American National Aeronautics and Space Administration patented a device designed to overcome some of the inherent variability of the technique (Low et al, 1972).…”