title: Evaluation of analgesia resulting from extracorporeal shock wave therapy and radial pressure wave therapy in the limbs of horses and sheep.
abstract: OBJECTIVE
  To identify the duration and potential mechanisms of analgesia following extracorporeal shock wave therapy (ESWT) and radial pressure wave therapy (RPWT) in limbs of horses and sheep.
  
  
  METHODS
  6 horses and 30 sheep.
  
  
  METHODS
  An electrical stimulus was used to identify the nociceptive threshold for each horse daily for 3 days before treatment (baseline) with ESWT or RPWT, 8 hours after treatment, and at 24-hour intervals for 7 days after treatment. Testing was conducted for the treatment field (midmetacarpus or midmetatarsus) and nerve field (medial and lateral forelimb heel bulbs) distal to a treatment site that included the nerve on the abaxial surface of the proximal sesamoid bone. All 4 limbs of 30 sheep were treated with ESWT, RPWT, or a sham treatment. Two sheep were euthanatized daily and tissue harvested for histologic evaluation of nerves, and concentrations of substance P and calcitonin gene-related peptide were measured in the skin and periosteum.
  
  
  RESULTS
  Values did not differ significantly between baseline and after treatment for the treatment field or nerve field sensation. There was a large difference in the slope when data for horses were plotted for the first 3 days after treatment, compared with the slope for days 4 to 7 after treatment. No differences were found in neuropeptide concentrations after treatment of the sheep, but there was an inflammatory response in the treated nerves.
  
  
  CONCLUSIONS
  A small cutaneous analgesic effect may exist at the treatment site for approximately 3 days after ESWT or RPWT in horses.
authors.affiliation: Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA.
authors.forename: Scott R
authors.initials: SR
authors.lastname: McClure
authors.forename: Iona M
authors.initials: IM
authors.lastname: Sonea
authors.forename: Richard B
authors.initials: RB
authors.lastname: Evans
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Yaeger
mesh_terms: D000698:Analgesia / Q000379:methods*; D000704:Analysis of Variance; D000818:Animals; D004558:Electric Stimulation; D005121:Extremities / Q000528:radiation effects*; D019220:High-Energy Shock Waves / Q000627:therapeutic use*; D006734:Horse Diseases / Q000628:therapy*; D006736:Horses; D009479:Neuropeptides / Q000378:metabolism; D010146:Pain / Q000662:veterinary*; D059408:Pain Management; D010525:Peripheral Nerves / Q000528:radiation effects; D011312:Pressure; D012756:Sheep; D012757:Sheep Diseases / Q000628:therapy*; D013997:Time Factors
chemical_list: D009479:Neuropeptides