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Aims

To characterise keratomas using contrast enhanced computed tomography (CECT) to facilitate complete surgical excision and provide information regarding post operative morbidity.

Methods

Records of horses with histologically confirmed keratomas who underwent CECT were reviewed. Historical and clinical details, CECT characteristics, surgical approach and outcome were reviewed.

Results

Ten horses, mean age 9.3 years, exhibiting recurrent or chronic grade 3 to 5/5 lameness for 5 weeks to 2 years, had histologically confirmed keratomas characterised and removed following CECT. Radiographs failed to reveal evidence of keratomas in 5/10 cases. Eleven keratoma lesions affecting the dorsal midline (n = 5), lateral hoof wall (n = 2), medial hoof wall (n = 3) and solar surface of the third phalanx (P3) (n = 1) were identified. Keratomas had a broad (n = 6) or narrow (n = 4) based attachment to the laminar surface, were classified as columnar (n = 5) or spherical (n = 5), measured 3–15 mm wide and 5–52 mm in length. Contrast material delineated keratoma margins by contrast enhancement within the lesion (n = 4) or attenuation of contrast material by the lesion (n = 6) suggesting surrounding hypervascularity or compression of surrounding vasculature, respectively. Defects in the distal phalanx (n = 5), abnormal vascularity (n = 10) and abscessation (n = 6) around the lesion were also identified. Proximal to distal and medial to lateral limits of the keratoma were marked on the hoof wall allowing complete excision via a partial hoof wall (PHWR [n = 7]) or complete hoof wall resection (CHWR [n = 3]). Soundness (mean 7 weeks) and no recurrence was achieved in all cases. Hoof wall defect healing was protracted in cases in which CECT attenuation of vascularity was evident around the defect.

Conclusions

Contrast enhanced computed tomography allows comprehensive characterisation of keratomas, determining location, vascularity and extent of laminar and P3 involvement. Accurate surgical landmarks are obtained so complete surgical excision is facilitated, the degree of hoof wall resection is minimised and recurrence is prevented. Those lesions with attenuation of vascularity around them on CECT are more likely to have protracted healing of the hoof wall defect.

Ethical animal research

Not required by this Congress: retrospective clinical study. Sources of funding: None. Competing interests: None.