Heat pain detection threshold is associated with the area of secondary hyperalgesia following brief thermal sensitization: a study of healthy male volunteers.
The area of secondary hyperalgesia following brief thermal sensitization (BTS) of the skin and heat pain detection thresholds (HPDT) may both have predictive abilities in regards to pain sensitivity and clinical pain states. The association between HPDT and secondary hyperalgesia, however, remains unsettled, and the dissimilarities in physiologic properties suggest that they may represent 2 distinctively different pain entities. The aim of this study was to investigate the association between HPDT and BTS-induced secondary hyperalgesia.



A sample of 121 healthy male participants was included and tested on 2 separate study days with BTS (45°C, 3 minutes), HPDT, and pain during thermal stimulation (45°C, 1 minute). Areas of secondary hyperalgesia were quantified after monofilament pinprick stimulation. The pain catastrophizing scale (PCS) and hospital anxiety and depression scale (HADS) were also applied.



A significant association between HPDT and the size of the area of secondary hyperalgesia (p<0.0001) was found. The expected change in area of secondary hyperalgesia due to a 1-degree increase in HPDT was estimated to be -27.38 cm2, 95% confidence interval (CI) of -37.77 to -16.98 cm2, with anR2of 0.19. Likewise, a significant association between HADS-depression subscore and area of secondary hyperalgesia (p=0.046) was found, with an estimated expected change in secondary hyperalgesia to a 1-point increase in HADS-depression subscore of 11 cm2, 95% CI (0.19-21.82), and withR2of 0.03. We found no significant associations between secondary hyperalgesia area and PCS score or pain during thermal stimulation.



HPDT and the area of secondary hyperalgesia after BTS are significantly associated; however, with anR2of only 19%, HPDT only offers a modest explanation of the inter-participant variation in the size of the secondary hyperalgesia area elicited by BTS.
Department of Anesthesiology, 4231, Centre of Head and Orthopedics, Rigshospitalet.
Morten Sejer
MS
Hansen
Copenhagen Trial Unit, Centre for Clinical Intervention Research, Department 7812.
Jørn
J
Wetterslev
Section of Biostatistics, Faculty of Health, Copenhagen University, Copenhagen.
Christian Bressen
CB
Pipper
Department of Anesthesiology, 4231, Centre of Head and Orthopedics, Rigshospitalet.
Mohammad Sohail
MS
Asghar
Department of Anesthesiology, Department Z, Bispebjerg Hospital, Copenhagen, Denmark.
Jørgen Berg
JB
Dahl
catastrophization; central nervous system sensitization; central sensitization; healthy volunteers; hyperalgesia; pain; pain threshold; secondary hyperalgesia