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

Abstract

Background: Pneumosinus dilatans and pneumocoele sinus describe abnormal hyperpneumatisation of paranasal sinuses, with the latter being accompanied by thinning of bony walls. Although recognised in human and equine medicine, to the authors' knowledge, this condition's computed tomography (CT) findings and successful surgical approach in horses have not previously been reported in conjunction. Advanced imaging, particularly CT, is pivotal for identifying abnormal sinus expansion and associated nasal obstruction. Study design: Case report. Clinical summary: A 2-year-5-month-old Cob filly presented with a 1-month history of progressive inspiratory stertor and weight loss, unresponsive to systemic corticosteroids. Physical examination revealed marked inspiratory stertor. Endoscopy suggested narrowing of nasal passages but was subjective and did not identify the underlying cause. Standing CT of the head demonstrated extensive, bilateral dilation of the dorsal and ventral conchal sinuses with marked thinning of axial sinus walls. The nasomaxillary apertures were occluded, and the dorsal and middle nasal meatuses were markedly narrowed or obliterated. No evidence of sinusitis or other intraluminal disease was present. Transnasal diode-laser fenestrations into the dorsal and ventral conchal sinuses established permanent communication with the nasal cavity. Foley catheters were placed for postoperative flushing. A temporary tracheostomy ensured airway patency. Seventeen days postoperatively, the filly showed complete resolution of inspiratory stertor. Endoscopic evaluation revealed large, epithelialised fistulae and restoration of normal nasal meatus dimensions. Long-term follow-up confirmed persistent clinical normality with no recurrence. Main limitations: Single case report. Conclusions: CT imaging was essential for diagnosis and surgical planning for a case of pneumocoele sinus in a horse. Creation of large, permanent fenestrations between the conchal sinuses and nasal cavity successfully equalised sinus pressure, reversed nasal obstruction, and resulted in an excellent long-term outcome. This condition should be considered as a differential diagnosis in equine upper airway obstruction