Surgical treatment of headshaking by removal of a paracondylar process fragment via modified hyovertebrotomy approach: A detailed anatomical and surgical description in an adult horse.
Authors: Spiesshofer Pius, Hawkins Alex E, Berner Dagmar, Previdelli Renato L, Fiske-Jackson Andrew R
Journal: Veterinary surgery : VS
Summary
# Editorial Summary: Surgical Management of Paracondylar Process Fracture-Induced Headshaking Violent, progressive headshaking can severely compromise safety and performance, yet identifying its underlying cause remains challenging in equine practice. This 2024 case report and anatomical study describes a modified hyovertebrotomy approach for surgical access to the paracondylar process (PCP)—a bony prominence at the occipital condyle—with detailed dissection of five equine heads to map critical neurovascular anatomy. A seven-year-old mare presenting with acute, escalating headshaking and high sensitivity to palpation over the right PCP was found via CT and ultrasonography to have a fracture fragment; surgical excision via the modified approach successfully resolved clinical signs, with the horse returning to light work without recurrence over two-and-a-half years of follow-up. Critical anatomical landmarks including the caudal meningeal vessels and the glossopharyngeal and hypoglossal nerves must be carefully preserved during the procedure to avoid serious complications. For practitioners managing horses with refractory headshaking, this work demonstrates that CT and ultrasonographic imaging can identify PCP fractures as a treatable underlying pathology, and that surgical intervention—when anatomically feasible and performed by experienced surgeons—offers a realistic chance of complete resolution rather than lifelong management of a dangerous clinical sign.
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Practical Takeaways
- •Consider paracondylar process fracture as a differential diagnosis in cases of acute-onset violent headshaking, especially when the horse is reactive to palpation over this region
- •CT imaging combined with ultrasonography can reliably identify paracondylar process fractures to guide surgical decision-making
- •Surgical removal of paracondylar process fragments via modified hyovertebrotomy is a viable treatment option that can result in complete resolution of headshaking with good long-term outcomes
Key Findings
- •A modified hyovertebrotomy approach successfully accessed and removed a paracondylar process fracture fragment in a mare with violent headshaking
- •Complete resolution of headshaking occurred postoperatively with the horse returning to light work 2.5 years after surgery
- •Critical anatomical structures adjacent to the paracondylar process include the caudal meningeal artery/vein and glossopharyngeal and hypoglossal nerves that must be avoided during surgical dissection
- •CT and ultrasonography were effective diagnostic tools for identifying the paracondylar process fracture