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Standing trans-nasal endoscopic guided CO2 laser fenestration of the palatine bone to access the sphenopalatine sinus in a horse.

OBJECTIVE
To describe a novel standing trans-nasal endoscopic guided CO2 laser fenestration approach to access the sphenopalatine sinus (SPS) in the horse.


STUDY DESIGN
Case report.


ANIMALS
Cadaver study and client-owned 20-year-old Warmblood gelding.


METHODS
The rostral palatine bone within the nasopharynx was investigated as a possible site for fenestration to access the SPS in cadavers. The ability to fenestrate the SPS was tested in cadavers using a flexible endoscope and CO2 laser fiber inserted via biopsy channel. The fenestration procedure was then performed in a clinical case presented for unilateral epistaxis where a soft tissue attenuating mass in the right SPS was identified with standing computed tomography (CT).


RESULTS
The cadaver study demonstrated the appropriate site within the nasopharynx midway between the vomer and dorsal conchal wall. The CO2 laser successfully ablated the mucosa and palatine bone to enable endoscopic access to the palatine portion of the SPS. The endoscopic procedure was performed as a two-step process via standing sedation due to mucosal bleeding obscuring visualization. Access to the SPS through fenestration allowed biopsy under direct endoscopic visualization with long-handled bronchoesophageal forceps inserted via the ipsilateral middle meatus. The mass within SPS was determined to be an undifferentiated carcinoma. Further treatment was declined and the horse euthanized 6 months following the procedure due to acute onset of neurologic symptoms.


CONCLUSION
Endoscopically guided fenestration of the rostral palatine bone within the nasopharynx using CO2 laser in the standing horse provided good access and visualization of the palatine portion of the SPS.