Effects of Repeated Monopolar Pulsed Capacitive Radiofrequency Energy Treatments on Mechanical Nociceptive Thresholds and Skin Temperature in Show-Jumping Horses with Thoracolumbar Pain.

Overview

• This study investigated the impact of repeated monopolar pulsed capacitive radiofrequency energy treatments (CRET therapy) on pain sensitivity and skin temperature in show-jumping horses suffering from chronic thoracolumbar pain.
• The researchers compared treated horses to a sham control group to assess changes in mechanical nociceptive thresholds (pain sensitivity) and surface skin temperature over time.

Study Design and Methods

• Subjects: Fifteen show-jumping horses experiencing chronic thoracolumbar pain participated in the study.
• Groups: The horses were randomly assigned into two groups:
  • Ten horses received CRET treatment.
  • Five horses underwent a sham (placebo) procedure.
• Treatment Protocol:
  • Monopolar capacitive radiofrequency device operating at 500 kHz was used.
  • Five treatment sessions were conducted, each 72 hours apart.
• Measurements:
  • Mechanical Nociceptive Thresholds (MNT): Assessed before treatment, after each session, and throughout a 45-day follow-up to evaluate changes in pain sensitivity.
  • Infrared Thermography: Used to measure skin surface temperature before and after each session to observe immediate thermal responses.

Data Analysis

• Linear mixed-effects models were used for MNT data, considering:
  • Treatment group (CRET vs. sham)
  • Time (different assessment points)
  • Anatomical site (exact location on the horse’s back)
  • Interactions between these factors
• Significance was defined with p-values less than 0.0001 for key effects.

Key Findings

• Effect on Pain Sensitivity:
  • CRET treatment induced a progressive increase in mechanical nociceptive thresholds (MNT), meaning horses became less sensitive to mechanical pain stimuli.
  • The increase in MNT was significantly greater in the CRET group compared to sham starting from the second treatment session.
  • Increased MNT levels persisted throughout the 45-day follow-up, indicating a lasting pain-relieving effect.
• Effect on Skin Temperature:
  • Skin surface temperature rose after both the CRET treatment and sham procedures.
  • No significant differences in thermal changes were detected between the groups, suggesting that the CRET protocol did not cause an immediate or greater thermographic response than placebo.

Interpretation and Implications

• The findings support the use of monopolar capacitive CRET therapy as a non-invasive treatment option to reduce mechanical pain sensitivity in horses with chronic thoracolumbar pain.
• The lack of a significant difference in skin temperature changes suggests that analgesic effects are not directly linked to immediate alterations in surface blood flow or temperature detectable by thermography.
• Repeated sessions are likely needed for the treatment to produce cumulative and sustained improvements in pain thresholds.
• These results may guide veterinarians in managing back pain in athletic horses, potentially improving comfort and performance without relying on drugs.

Limitations and Future Directions

• Small sample size (only 15 horses) may limit generalizability.
• The sham procedure increased skin temperature similarly to active treatment, indicating possible placebo effects or confounding factors in thermographic measurements.
• Future studies could investigate the long-term functional and performance outcomes of CRET therapy and explore biological mechanisms underlying the analgesic effects.
• Comparisons with other physical therapy modalities or combinations thereof could further optimize treatment protocols for equine back pain.