Pneumocephalus secondary to removal of an osteoma from the paranasal sinuses of a horse.

This study reports a case where a 2-year-old horse was diagnosed with osteoma, a mineralized mass in the left paranasal sinuses, leading to a facial deformity and nasal discharge. After undergoing surgery for its removal, the horse developed pneumocephalus—a condition where air becomes present within the skull, typically caused during the surgery. Despite these complications, the horse was performing normally after two years from the surgery.

Physical Symptoms and Diagnosis

• The horse, a 2-year-old Quarter Horse, exhibited a left-sided facial deformation and unilateral nasal and ocular discharge.
• Physical examination showed a convexity in the left frontonasal region, alongside the aforementioned symptoms and reduced air flow through the left nostrils.
• Medical imaging, through radiography and computed tomography, revealed a mineralized mass taking up much of the left paranasal sinuses. This mass was subsequently identified as osteoma, a type of bone tumor.

Surgical Procedure and Complications

• The osteoma mass was attempted to be debulked via a surgical procedure. However, full removal was not possible due to the tight adhesion the mass had with the frontal and maxillary bones.
• After the surgery, the horse developed temporary pyrexia (fever) and colic—a condition causing severe abdominal discomfort.
• Additional post-surgery radiography showed gas opacities in the lateral ventricles of the brain, indicating a condition known as pneumocephalus. This is usually an iatrogenic problem, meaning it was likely caused by the surgery.

Post-Surgery and Conclusions

• Despite developing pneumocephalus, the horse did not display any neurological symptoms and was observed to behaving normally two years after the surgical procedure.
• The findings from this case study emphasize the potential risk of intracranial complications like pneumocephalus in horses undergoing paranasal sinus surgery.
• The use of computed tomography for horses with a mass in the paranasal sinuses is therefore suggested to be helpful in identifying the mass boundaries and devising an appropriate surgical plan.