Caudal anaesthesia of the infraorbital nerve for diagnosis of idiopathic headshaking and caudal compression of the infraorbital nerve for its treatment, in 58 horses.
Authors: Roberts V L H, Perkins J D, Skärlina E, Gorvy D A, Tremaine W H, Williams A, McKane S A, White I, Knottenbelt D C
Journal: Equine veterinary journal
Summary
# Editorial Summary: Infraorbital Nerve Surgery for Idiopathic Headshaking Idiopathic headshaking remains a frustrating condition with limited treatment options, and this multicentre retrospective study sought to establish a diagnostic protocol and evaluate the efficacy of caudal compression surgery on the infraorbital nerve across 58 horses with extended follow-up. A posterior ethmoidal nerve (PET) block was performed diagnostically in 27 horses, yielding a positive response in 85% of cases and supporting the hypothesis that this is primarily a facial pain syndrome amenable to nerve-targeted intervention. Whilst initial surgical success was achieved in 63% of horses, the 18-month median follow-up revealed a concerning recurrence rate, with only 49% maintaining a successful outcome long-term; post-operative nose-rubbing developed in 63% of cases, though this resolved in all but four horses. Technical modifications—including additional coils or laser cautery—and a positive PET block response did not significantly influence surgical outcomes or complications. For practitioners managing headshakers where alternative treatments have failed, caudal compression surgery remains the most promising option before euthanasia is considered, though clinicians should counsel owners realistically about recurrence risk and counsel patience during post-operative recovery, whilst acknowledging that the underlying pathogenesis remains poorly understood and warrants further investigation to refine surgical technique and improve long-term prognosis.
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Practical Takeaways
- •Use PET block as a reliable diagnostic tool for headshaking—85% positive predictive value supports this as the first-line diagnostic protocol before committing to surgery
- •Counsel owners that caudal compression surgery offers 49% final success with significant recurrence risk; reserve for cases where euthanasia is otherwise the only option
- •Expect post-operative nose-rubbing in most cases and plan monitoring; though usually self-limiting, prepare owners for potential euthanasia in refractory cases
Key Findings
- •Posterior ethmoidal nerve (PET) block was positive in 23 of 27 horses (85%), providing a diagnostic protocol for headshaking investigation
- •Initial surgical success rate was 63% (35/57 horses), but 26% experienced recurrence 9-30 months post-operatively, reducing final success to 49% (28/57)
- •Post-operative nose-rubbing occurred in 63% of horses (30/48), resolving in all but 4 cases that required euthanasia
- •Changes to surgical technique (additional coils, laser cautery) and positive PET block response did not significantly improve outcomes or reduce complications