Severe orbital haematoma after attempted maxillary nerve block in a horse

TEARS/LIDS Elmont – The case report by Matthew J. Woodman of the Cornell Ruffian Equine Specialists in Elmont, New York, USA, and Canadian colleagues describes the rare complication of third eyelid prolapse in a horse following maxillary nerve block and the successful treatment with temporary tarsorrhaphy.

A 20-year-old Quarter Horse gelding was presented for a routine dental examination. Periodontitis and dislocation of tooth 108 were diagnosed and oral extraction was planned. After a blind maxillary nerve block was unsuccessful, it was decided to perform the procedure under general anaesthesia. On awakening, a focal superficial corneal ulcer, marked retrobulbar swelling, mild exophthalmos, and marked swelling and prolapse of the third eyelid (nictitating membrane) were observed. Clinical signs persisted for over 48 hours despite systemic and topical ocular anti-inflammatory and antibiotic treatment. Temporary tarsorrhaphy was performed after 48 hours and the horse was discharged after 5 days of hospitalisation and resolution of clinical signs.

In the April 2024 issue of the CANADIAN VETERINARY JOURNAL, the authors use this case report to demonstrate that although blind maxillary nerve block is very helpful in facilitating tooth extraction, it is associated with potential complications due to inadvertent vascular puncture, which in this case were managed with medical measures and a temporary tarsorrhaphy. (bs)

Authors: Woodman MJ, MacKenzie J, Osinchuk S, Husulak M. Correspondence: Michelle Husulak, Department of Large Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, Saskatchewan S7N 5B4, Canada. Email: michelle.husulak@usask.ca Study: Severe orbital hematoma with third eyelid swelling and prolapse following a blind maxillary nerve block in a horse. Source: Can Vet J. 2024 Apr;65(4):359-362. PMID: 38562986; PMCID: PMC10945441. Web: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10945441/