Department of Clinical Sciences and Services, Royal Veterinary College, University of London, Hatfield, UK.
Hull York Medical School, University of York, Heslington, York, UK.
Vet Anaesth Analg. 2020 Nov;47(6):835-842. doi: 10.1016/j.vaa.2020.04.016. Epub 2020 Sep 6.
To develop a technique for performing the mandibular nerve block in Nile crocodiles.
Experimental cadaveric study.
A total of 16 juvenile Nile crocodile heads.
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 one-sample t test or Mann-Whitney U test. Significance was set at p < 0.05.
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 bones in 100% cases. In all the hemimandibles, the rostrocaudal spread of contrast was > 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 dorsoventral and mediolateral 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).
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.
开发一种在尼罗鳄中进行下颌神经阻滞的技术。
实验性尸体研究。
共 16 个头骨幼年尼罗鳄。
为了研究下颌神经的行程，对其中一个头进行了解剖。对其中两个头进行了计算机断层扫描（CT）检查，以确定有用的标志。然后，将皮下注射针穿过 17 个半下颌骨的外部下颌骨窗（13 个头），并注射亚甲蓝和碘海醇混合物。注射体积分别为 0.5（n=7）和 1.0 毫升（n=10），用于长度小于 15 厘米和大于等于 15 厘米的半下颌骨。用 CT 和解剖学解剖分别评估碘海醇的扩散和亚甲蓝的神经染色。数据采用单样本 t 检验或曼-惠特尼 U 检验进行分析。显著性设置为 p<0.05。
解剖和影像学均证实外部下颌骨窗是一种有用的针插入解剖标志。在定位针后获得的 CT 图像确认其尖端位于由角骨和冠状骨融合形成的内侧骨性下颌骨表面的 100%病例中。在所有半下颌骨中，对比剂的前后扩散大于 23 毫米。在组 1.0 中，染色的下颌神经在颞区的长度以及染色的下颌神经内侧支的长度，以及碘海醇的背腹和内外扩散均大于组 0.5（p<0.001）。组 1.0 中的碘海醇的尾端扩散大于组 0.5（p=0.01）。
本研究中开发的技术是可行的。两种注射量均导致下颌神经染色。在感兴趣的解剖区域对比剂的扩散可能导致成功的感觉阻滞。
