title: Antinociceptive effects of low dose lumbosacral epidural ropivacaine in healthy ponies.
abstract: The objective of this study was to evaluate the safety and efficacy of low dose lumbosacral epidural ropivacaine in ponies. Antinociceptive effects of epidural ropivacaine were evaluated by means of mechanical nociceptive thresholds (MNTs) at several spinal levels in conscious ponies. The effects of ropivacaine on nociceptive afferent transmission to the spinal cord were also assessed by measuring spinal cord somatosensory evoked potentials (SSEPs) in anaesthetised ponies. Ataxia scores were determined in conscious ponies to assess the effects on motor function. A randomised, placebo controlled, double blind cross-over design was used. Low dose lumbosacral epidural ropivacaine led to increases in MNTs at various anatomical locations with a maximum effect at the lumbosacral and sacrococcygeal regions, both with respect to increase in threshold and duration of effect. Analysis of SSEPs showed that epidural ropivacaine influenced both Aβ- and Aδ-mediated afferent transmission to the spinal cord at the level of the lumbosacral junction. Ponies showed mild ataxia after low dose lumbosacral epidural ropivacaine, but all ponies remained standing. Application of low dose lumbosacral epidural ropivacaine provided safe and efficacious antinociceptive effects in conscious and anaesthetised ponies, and could therefore be a valuable addition to multimodal analgesic protocols in Equidae.
authors.affiliation: Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 114, NL-3584 CM Utrecht, The Netherlands. j.p.a.m.vanloon@uu.nl
authors.forename: Johannes P A M
authors.initials: JP
authors.lastname: van Loon
authors.forename: Eveline S
authors.initials: ES
authors.lastname: Menke
authors.forename: Arie
authors.initials: A
authors.lastname: Doornenbal
authors.forename: Willem
authors.initials: W
authors.lastname: Back
authors.forename: Ludo J
authors.initials: LJ
authors.lastname: Hellebrekers
mesh_terms: D000577:Amides / Q000009:adverse effects*; D015360:Analgesia, Epidural / Q000662:veterinary; D000779:Anesthetics, Local / Q000009:adverse effects*; D000818:Animals; D018592:Cross-Over Studies; D005073:Evoked Potentials, Somatosensory; D006736:Horses / Q000502:physiology*; D007268:Injections, Epidural / Q000662:veterinary; D008161:Lumbosacral Region / Q000502:physiology*; D008297:Male; D059225:Nociception; D010147:Pain Measurement / Q000662:veterinary; D000077212:Ropivacaine; D013116:Spinal Cord / Q000502:physiology*
chemical_list: D000577:Amides; D000779:Anesthetics, Local; D000077212:Ropivacaine