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.