Mandibular nerve block in juvenile Nile crocodile: a cadaveric study

Bianchi, C; Adami, C; Dirrig, H; Cuff, A; d’Ovidio, D; Monticelli, P

Abstract

Study design
Experimental cadaveric study.

Animals
A group of 16 juvenile Nile crocodile heads.

Methods
To study the course of the mandibular nerve, one head was dissected. Computed tomography (CT) examination was performed in two heads to identify useful landmarks. Thereafter, a hypodermic needle was inserted through the external mandibular fenestra of 17 hemimandibles (13 heads) and a mixture of methylene blue and iohexol was injected. Injection volumes were 0.5 (n = 7) and 1.0 mL (n = 10) for hemimandibles < 15 and ≥ 15 cm long, respectively. Iohexol spread and nerve staining with methylene blue were assessed with CT and anatomical dissection, respectively. Data were analysed with either one sample t-test or Mann-Whitney Rank Sum test. p < 0.05

Results
Both anatomical dissection and imaging confirmed the external mandibular fenestra as a useful anatomical landmark for needle insertion. The CT images acquired after needle positioning confirmed that its tip was located on the medial bony mandibular surface formed by the fusion of the angular and coronoid bone in 100% of the cases. In all the hemimandibles, the rostro-caudal spread of contrast was greater than 23 mm. The length of the stained mandibular nerve in the temporal region and of the stained medial branch of the mandibular nerve, as well as the dorso-ventral and medio-lateral spread of iohexol, was greater in group 1.0 than in group 0.5 (p < 0.001). The caudal spread of iohexol was greater in group 1.0 than in group 0.5 (p = 0.01).

Conclusions
and clinical relevance The technique developed in this study is feasible. Both injection volumes resulted in staining of the mandibular nerve. The spread of contrast in the anatomical region of interest may result in successful sensory block.

Citation

Bianchi, C., Adami, C., Dirrig, H., Cuff, A., d’Ovidio, D., & Monticelli, P. (2020). Mandibular nerve block in juvenile Nile crocodile: a cadaveric study. Veterinary Anaesthesia and Analgesia, https://doi.org/10.1016/j.vaa.2020.04.016

• Journal Article Type: Article
• Acceptance Date: Apr 5, 2020
• Publication Date: Sep 6, 2020
• Deposit Date: Sep 11, 2020
• Publicly Available Date: Sep 7, 2021
• Journal: Veterinary Anaesthesia and Analgesia
• Print ISSN: 1467-2987
• Electronic ISSN: 1467-2995
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• DOI: https://doi.org/10.1016/j.vaa.2020.04.016
• Public URL: https://rvc-repository.worktribe.com/output/1375919
• Publisher URL: https://doi.org/10.1016/j.vaa.2020.04.016