Caudal compression of the infraorbital nerve: a novel surgical technique for treatment of idiopathic headshaking and assessment of its efficacy in 24 horses.

The research article discusses a new surgery, which involves the compression of the infraorbital nerve using platinum coils, designed as a treatment for horses diagnosed with idiopathic headshaking, a condition likened to human neuropathic facial pain syndromes. The researchers aimed to determine the success rate of this technique by reviewing the cases of 24 horse patients.

Reasons for Designing and Reporting the Technique

• The researchers identified idiopathic headshaking in horses, a condition without known causes, as having significant similarities to human neuropathic facial pain syndromes linked with post herpetic and trigeminal neuralgia. These are both nerve disorders characterized by intense facial pain.
• Both these conditions stem from irregular sensory functions within the peripheral or central pathways of the trigeminal nerve (TgN).
• Limiting the input from the TgN can potentially help in controlling the perception of pain.
• Previous research has shown that rhizotomy, a surgical procedure that cuts off nerve roots from the spinal cord, of the infraorbital branch of the TgN has poor efficacy. This suggested the need for a new, more effective approach.
• The researchers’ new technique is centered on compressing the nerve at a more caudal (towards the back) location within the infraorbital canal.

Research Objective and Method

• The primary objective was to establish whether caudal compression of the infraorbital nerve using platinum coils in horses with idiopathic headshaking can lead to a reduction in clinical signs.
• The surgical technique used platinum embolisation coils and was carried out under fluoroscopic guidance, a type of medical imaging that shows a continuous X-ray image on a monitor.
• The researchers reviewed clinical records of 24 horses that had undergone this procedure and gathered follow-up information via telephone questionnaires with the horse owners or referring veterinary surgeon.

Findings and Conclusions

• All 24 horses had undergone at least one surgical procedure, with a median follow-up time of 6 months.
• Two horses that had the procedure just 2 weeks prior were excluded from the outcome analysis.
• After one surgery, around 59% of the horses (13/22) had a successful outcome.
• For the 9 horses that didn’t improve after the first surgery, the procedure was repeated in 6 instances. Two of these cases were eventually successful.
• The overall success rate was around 84.2% (16/19).
• The new technique appears to be more effective in preventing input from the TgN than the previously described infraorbital neurectomy.
• The research team concluded that the technique needs further refinement despite having a promising efficacy rate.