Percutaneous doxycycline sclerotherapy in a horse with a mandibular aneurysmal bone cyst.

OBJECTIVE: To describe the use and outcome of sclerotherapy with intralesional doxycycline foam in a horse with a mandibular aneurysmal bone cyst. STUDY DESIGN: Case report. ANIMALS: Client-owned 1 year old Standardbred filly. METHODS: The horse presented for progressive mandibular swelling. A 10 mg/mL doxycycline foam was prepared for intralesional injection. Three doses were injected into the lesion under computed tomographic guidance at 6 and 15 weeks after initial treatment. Volume reduction was monitored after each treatment with 3D volumetric rendering and region of interest segmentation using commercially available software. RESULTS: The volume of the lesion decreased from 458.7455 cm3 before treatment, to 363.3101 cm3 at 6 weeks, 273.5855 cm3 at 15 weeks, and 247.2316 cm3 6 months later, resulting in a total reduction of 54% of the initial volume. Bone formation was noted in the lesion. No adverse effects related to doxycycline foam injections were noted. The mandibular swelling was resolved after treatment. CONCLUSION: Intralesional doxycycline sclerotherapy was shown to be efficacious in reducing the volume of the aneurysmal bone cyst in the horse presented in this report. There was complete resolution of mandibular swelling with no side effects related to the intralesional injections.

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.