title: Preoperative back pain is associated with diverse manifestations of central neuroplasticity.
abstract: Increased or decreased gain in central nervous system processing after surgery, i.e. neuroplasticity, may play an important role in postoperative pain. Identification of patient subgroups particularly vulnerable to either type of post-surgical neuroplasticity is thus of interest. Preoperative pain has also been suggested to increase vulnerability to post-surgical chronic pain complications due to central facilitation. To study if back pain preoperatively is associated with differences in central sensory processing, we measured transcutaneous electric sensation, pain detection and pain tolerance thresholds at the upper arm, lower back and lower leg in 52 consecutive patients scheduled for back surgery in a blinded, prospective fashion. Patients with no pain had significantly lower pain thresholds than patients with pain in the leg, and significantly higher pain thresholds than those with pain in the back. These results suggest that preoperative pain can induce diverse central neuroplastic changes, i.e. inhibition and facilitation, and that the nature of this neuroplasticity depends on the nature of the pain involved. The presence of facilitation may be the basis of the increased vulnerability described in some studies of patients with significant preoperative pain, whereas the implications of reduced pain sensitivity are less clear. The demonstration of neuroplasticity and its diversity are, however, likely to be of significant clinical relevance.
authors.affiliation: Nociception Research Group, Tiefenaustrasse 110/211, CH-3004 Berne, Switzerland Department of Anaesthesia, Geneva University Hospital, Rue Micheli du Crest 24, CH-1211 Geneva 14, Switzerland Laboratory for Experimental Pain Research, Centre for Sensory-Motor Interaction, University of Aalborg, Fredrik Bajers Vej 7, DK-9220 Aalborg Ø, Denmark.
authors.forename: Oliver H G
authors.initials: OHG
authors.lastname: Wilder-Smith
authors.forename: Edömer
authors.initials: E
authors.lastname: Tassonyi
authors.forename: Lars
authors.initials: L
authors.lastname: Arendt-Nielsen
mesh_terms: D000328:Adult; D001416:Back Pain / Q000503:physiopathology* / Q000601:surgery; D004558:Electric Stimulation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009433:Neural Inhibition / Q000502:physiology; D009473:Neuronal Plasticity / Q000502:physiology*; D009475:Neurons, Afferent / Q000502:physiology; D009619:Nociceptors / Q000502:physiology; D017288:Pain Threshold / Q000502:physiology; D011300:Preoperative Care