Ultrasound-guided retrobulbar nerve block in donkey cadavers

Objective To develop and describe an acoustic window to access and inject the retrobulbar region in donkey cadavers.& nbsp;Study design Prospective cadaveric experimental study. Animals A total of 14 donkey cadaver heads.& nbsp;Methods Ultrasound landmarks for retrobulbar injection were identified by dissection of two cadavers. Ultrasound-guided retrobulbar injection of 3, 6 and 9 mL of contrast-lidocaine mixture (1:1) were evaluated using computed tomography (CT) in 12 cadavers for needle position and spread of injectate into the extraocular muscle cone.& nbsp;Results Real-time visualization of needle, extraocular muscle cone and optic nerve enabled successful intraconal instillation of injectate, as documented on CT images.& nbsp;Conclusions and clinical relevance Ultrasound-guided retrobulbar injections in cadaver donkeys provided adequate infiltration of the intraconal space.