Introduction
Surgical access to the equine paranasal sinuses can be obtained by bone
flap techniques (Auer et al 2019). Two main techniques have been
described for the exploration of the paranasal sinuses, the maxillary,
and the frontonasal bone flaps (Freeman et al 1990; Auer et al2019). The maxillary flap provides excellent access to the maxillary
sinus, entrance to the ventral concha sinus and visualization of the
root of the first (109/209), second (110/210) and third (111/211)
molars. The frontonasal bone flap, affords access to the concho frontal
sinus, ethmoturbinate, caudal maxillary sinus and caudal nasal cavity
(Freeman et al 1990; Auer et al 2019).
Bone flap techniques are usually performed for the exploration and
treatment of the paranasal sinuses, or for the removal of sinus
neoplasia, cyst, and hematomas (Auer et al 2019; Cook and
Littlewort 1974). Progressive ethmoid hematomas (PEH) are encapsulated,
slow growing non-neoplastic masses (Greet 1992; Smith and Perkins 2010)
PEH usually extend into the nasal passages and nasopharynx or expand
into the paranasal sinuses pursuing the path of least resistance.
Treatment of PEH is difficult, with variable success and high
reoccurrence rates (Cook and Littlewort 1974; Greet 1992; Smith and
Perkins 2010). Horses with small PEH are commonly treated with Laser
ablation, cryotherapy, or chemical ablation with repeated intralesional
injections of 4% formal saline (Greet 1992; Schumacher 1998).However,
in larger expansive lesions; surgical abrasion(debridement or removal or
reduction?) via fronto nasal or maxillary flaps are more effective (Cook
and Littlewort 1974; Smith and Perkins 2010; Auer et al 2019).
This article describes the use of a combined frontonasal-maxillary bone
flap for the removal of a PEH invading into the sphenopalatine, frontal,
maxillary sinuses, and the nasal cavity in a horse.