Evaluation of a caudal midline glossectomy on tongue volume and upper airway cross-sectional areas in brachycephalic dogs: a cadaveric study.

Abstract

INTRODUCTION: Relative macroglossia may contribute to brachycephalic obstructive airway syndrome, the pathologic disorder associated with respiratory dysfunction commonly seen in brachycephalic dogs. Recent studies on brachycephalic dogs have demonstrated a relative macroglossia along with reduced air volume in the upper airway compared to non-brachycephalic dogs. Tongue reduction glossectomy may be a surgical option to address upper airway obstruction secondary to macroglossia. The objective of this study was to evaluate the effects of a caudal midline glossectomy (CMG) on tongue volume and upper airway cross-sectional areas. METHODS: Cadaveric brachycephalic dogs (&#x202f;=&#x202f;6) were positioned with the tongue retracted and jaw nearly closed. Computed tomography was performed to evaluate tongue volume and cross-sectional areas of tongue, oropharynx, palatal soft tissue and nasopharynx at two levels, the caudal aspect of the hard palate and pterygoid hamulae. A standardized CMG was performed. Positioning and CT scan were repeated. RESULTS: CMG resulted in a 20% decrease in tongue volume (from 87,546&#x202f;&#xb1;&#x202f;21,121 to 70,259&#x202f;&#xb1;&#x202f;17,586 mm;&#x202f;<&#x202f;0.01). CMG resulted in a 20 to 25% decrease in cross-sectional area of the tongue at both hard palate (from 1662&#x202f;&#xb1;&#x202f;311 to 1339&#x202f;&#xb1;&#x202f;254 mm;&#x202f;<&#x202f;0.01) and pterygoid hamulae (from 1425&#x202f;&#xb1;&#x202f;222 to 1041&#x202f;&#xb1;&#x202f;150 mm;&#x202f;<&#x202f;0.01), and 2 to 3-fold increase in cross-sectional area of the oropharynx at both hard palate (from 226&#x202f;&#xb1;&#x202f;68 to 595&#x202f;&#xb1;&#x202f;138 mm;&#x202f;<&#x202f;0.01) and pterygoid hamulae (from 110&#x202f;&#xb1;&#x202f;64 to 351&#x202f;&#xb1;&#x202f;37 mm;&#x202f;<&#x202f;0.01). DISCUSSION: This study provides preliminary guidelines toward the feasibility and potential benefit of CMG in select cases of macroglossia-associated upper airway obstruction.