Pneumocoele sinus: Computed tomographic findings and surgical approach in a 2-year-old Cob filly.

Overview

• This study reports on a 2-year-old Cob filly diagnosed with pneumocoele sinus, an abnormal expansion of the paranasal sinuses causing nasal obstruction, and details the CT imaging findings and successful surgical treatment using transnasal laser fenestrations.

Background

• Pneumosinus dilatans and pneumocoele sinus refer to abnormal over-inflation or hyperpneumatisation of the paranasal sinuses.
• Pneumocoele sinus is characterized by thinning of the bony sinus walls along with expansion.
• While known in both human and equine medicine, detailed computed tomography (CT) findings and surgical treatment strategies for horses have not been well documented together before.
• Advanced imaging, especially CT, plays a critical role in identifying abnormal sinus enlargement and associated nasal passage problems.

Case Description

• A 2-year-5-month-old Cob filly was presented with a 1-month history of progressive inspiratory stertor (noisy breathing during inhalation) and weight loss.
• The filly did not improve with systemic corticosteroids, indicating that inflammation was not the sole issue.
• Physical examination confirmed pronounced inspiratory stertor.
• Endoscopy showed narrowing of nasal passages but was subjective and failed to clarify the cause of obstruction.
• Standing CT scans of the head revealed:
  • Extensive, bilateral dilation of the dorsal and ventral conchal sinuses.
  • Marked thinning of the axial walls of the sinuses.
  • Occlusion of the nasomaxillary apertures, blocking natural sinus drainage.
  • Marked narrowing or obliteration of dorsal and middle nasal meatuses (air passages).
  • No evidence of sinusitis or other sinus disease inside the sinuses.

Surgical Intervention

• A transnasal diode-laser was used to create fenestrations (small openings) into the dorsal and ventral conchal sinuses.
• These fenestrations established permanent communications between the sinuses and the nasal cavity, allowing air pressure to equalize.
• Foley catheters were inserted to allow postoperative flushing of the sinus cavities.
• A temporary tracheostomy was performed to ensure the filly’s airway remained open during the early postoperative period.

Postoperative and Follow-up Outcomes

• Seventeen days after surgery, the filly showed complete resolution of inspiratory stertor, indicating restored airway patency.
• Endoscopic examination post-surgery revealed:
  • Large, epithelialized fistulae where laser fenestrations were made.
  • Normal dimensions of nasal meatuses, meaning the nasal passages were no longer obstructed.
• Long-term follow-up indicated:
  • Persistent clinical normality with no recurrence of symptoms.
  • Excellent long-term surgical outcome.

Conclusions and Clinical Significance

• This single case report highlights the importance of CT imaging for accurately diagnosing pneumocoele sinus and planning surgical intervention in horses.
• The creation of permanent fenestrations between the diseased sinuses and nasal cavity effectively equalizes sinus pressure and resolves nasal obstruction.
• The surgical approach is minimally invasive and provides excellent long-term results.
• Veterinarians should consider pneumocoele sinus as a differential diagnosis in cases of upper airway obstruction in horses, especially when symptoms do not respond to conventional treatments like corticosteroids.