Use of infrared thermography to detect injections and palmar digital neurectomy in horses.
Authors: Van hoogmoed Linda M, Snyder Jack R
Journal: Veterinary journal (London, England : 1997)
Summary
# Editorial Summary: Infrared Thermography for Detecting Equine Nerve Blocks and Neurectomy Infrared thermography offers a non-invasive method to visualise surface temperature changes reflecting underlying tissue metabolism and blood flow, potentially identifying inflammatory responses to therapeutic interventions. Van Hoogmoed and Snyder evaluated whether thermographic imaging could detect thermal signatures following diagnostic and therapeutic procedures including lumbar and suspensory ligament injections, tibial and palmar digital nerve blocks, and palmar digital neurectomy in horses. Local anaesthetic and neurolytic injections produced measurable thermal changes at the injection sites: lumbar region and suspensory ligament injections remained thermographically detectable for approximately two days, tibial nerve blocks with neurolytic agents for two days, whilst palmar digital nerve blocks showed thermal changes lasting 24 hours with bupivacaine but extended to five days with ammonium chloride. Although thermography proved sufficiently sensitive to distinguish treated regions from untreated controls, the technique lacked specificity—thermal patterns could not reliably differentiate between the different procedures or distinguish therapeutic injections from pathological inflammatory responses. For equine practitioners, this suggests thermography holds potential as a research and validation tool for confirming local anaesthetic placement and duration, yet cannot currently serve as a diagnostic technique to differentiate between various interventions or identify injury-related inflammation in clinical practice.
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Practical Takeaways
- •Infrared thermography can objectively document the thermal effects of nerve blocks and injections, potentially useful for monitoring treatment response in the first 1-5 days post-procedure
- •Different analgesic agents (bupivacaine vs ammonium chloride) produce distinctly different durations of detectable thermal change, which may help guide agent selection for diagnostic purposes
- •Thermography alone cannot differentiate between therapeutic injections and traumatic injury based on thermal patterns, so clinical correlation remains essential for diagnosis
Key Findings
- •Lumbar region and suspensory ligament injections produced detectable thermal patterns for 2 days post-procedure
- •Tibial nerve neurolytic agent infiltration showed significant thermal changes for 2 days
- •Palmar nerve analgesia with bupivacaine was thermographically detectable for 24 hours versus 5 days with ammonium chloride
- •Thermography is sensitive enough to detect inflammatory heat patterns but cannot discriminate between different procedures causing similar thermal responses