Study examines long-term outcomes after ceratohyoidectomy in equids
Bottom line
A new retrospective study in Animals reviewed long-term outcomes after ceratohyoidectomy in 33 equids with temporohyoid osteoarthropathy, including horses treated for both unilateral and bilateral disease. The paper adds to a relatively limited evidence base around how to manage THO surgically, especially as advanced imaging has made bilateral involvement easier to identify. THO is a progressive disorder of the temporohyoid joint that can cause facial nerve paralysis, vestibular signs, dysphagia, pain, and performance-limiting neurologic deficits. Prior literature has generally supported ceratohyoidectomy as a lower-risk alternative to partial stylohyoidectomy, with diagnosis often relying on guttural pouch endoscopy and CT helping define the extent of disease. (acvs.org)
Why it matters: For equine veterinarians, the main clinical question is no longer just whether to operate, but whether unilateral signs always justify unilateral surgery. Earlier work found that some horses with unilateral clinical signs actually had bilateral disease, and expert guidance now emphasizes evaluating both sides with endoscopy and, when available, CT. Existing outcome data suggest many horses improve after ceratohyoidectomy and can return to prior use, but residual cranial nerve deficits may persist, particularly if neurologic injury is established before surgery. That makes case selection, imaging, client counseling, and timing of referral especially important for the pet parent and care team. (pubmed.ncbi.nlm.nih.gov)
What to watch: Watch for whether this study shifts referral-center protocols toward more routine bilateral imaging assessment, and in selected cases, broader consideration of bilateral surgical management. (beva.onlinelibrary.wiley.com)
Key facts
- Study type
- Retrospective study
- Journal
- Animals
- Population
- 33 equids with temporohyoid osteoarthropathy
- Surgery studied
- Ceratohyoidectomy
- Disease pattern
- Unilateral and bilateral disease
- Condition
- Temporohyoid osteoarthropathy (THO)
- Clinical signs
- Facial nerve paralysis, vestibular signs, dysphagia, pain, and neurologic deficits
- Imaging context
- CT can help define the extent of disease, including bilateral involvement
A new study in Animals examines long-term outcomes after ceratohyoidectomy in 33 equids with temporohyoid osteoarthropathy, focusing on management of both unilateral and bilateral disease. That matters because THO can move quickly from subtle performance issues or ear-base pain to facial paralysis, vestibular dysfunction, dysphagia, and fracture-related neurologic decline, and the surgical approach has evolved as clinicians recognize that disease is often not confined to one side. (acvs.org)
THO has long been recognized as a progressive disorder involving osseous proliferation and possible ankylosis of the temporohyoid joint. Earlier case series described facial nerve deficits and vestibulocochlear signs as common presenting problems, and found guttural pouch endoscopy more reliable than radiography for diagnosis. Over time, CT has expanded clinicians’ ability to detect bilateral or more extensive disease, including changes in the hyoid apparatus, temporal bone, tympanic bulla, and adjacent structures. (pubmed.ncbi.nlm.nih.gov)
That imaging shift is central to why this paper is notable. Historically, treatment was often directed to the clinically affected side, and unilateral ceratohyoidectomy became favored because it reduces force transmission through the abnormal joint while avoiding some of the complications associated with partial stylohyoidectomy. ACVS guidance describes ceratohyoidectomy as a procedure intended to reduce pain and fracture risk, while noting that residual neurologic deficits can remain even when overall prognosis is favorable. (acvs.org)
The broader literature gives some context for expectations after surgery. In a 15-case retrospective series from Texas A&M, follow-up was available for 14 horses, average follow-up exceeded four years, eight of 10 athletic horses returned to previous use, and persistent deficits were usually limited to mild facial nerve paralysis or head tilt that were not functionally limiting. The authors concluded prognosis after ceratohyoidectomy was good for resolution of ataxia, though some cranial nerve deficits persisted. (pmc.ncbi.nlm.nih.gov)
There’s also a smaller but important literature on bilateral intervention. A 2014 case report described recurrence of clinical signs about two years after unilateral ceratohyoidectomy, with subsequent bilateral ceratohyoidectomy associated with resolution of signs. At the same time, commentary in Equine Veterinary Education has noted that most horses show evidence of bilateral disease, even when clinical signs are unilateral, while also cautioning that unilateral surgery has often still been successful. Taken together, that sets up the practical tension this new 33-equid study is addressing: when bilateral imaging changes should alter the surgical plan. (beva.onlinelibrary.wiley.com)
Expert and industry guidance is broadly aligned on a few points. ACVS advises checking both guttural pouches because THO can be bilateral, and says CT can be especially useful for surgical planning. AAEP proceedings have also reported better outcomes with surgical than medical management in some THO cohorts, reinforcing the role of referral-level workup and intervention when neurologic signs are progressing. (acvs.org)
Why it matters: For veterinary professionals, this is less about a brand-new procedure than about refining decision-making. If the new study supports good long-term outcomes in bilaterally affected equids, it may strengthen the case for more aggressive imaging workups and more individualized surgical planning rather than assuming the clinically louder side is the only side that matters. It also reinforces a familiar but important message for pet parents: surgery may improve balance, comfort, and function, but established facial or vestibular deficits may not fully resolve, especially when diagnosis is delayed. (acvs.org)
What to watch: The next question is whether this paper changes how equine referral centers define surgical candidacy for bilateral disease, and whether future studies can identify imaging or neurologic predictors that help veterinarians decide between unilateral and bilateral intervention, ideally with standardized outcome reporting and return-to-use data. (pubmed.ncbi.nlm.nih.gov)