Badawy Adel M, Eshra Eman A
Department of Veterinary Surgery, Anesthesiology and Radiology, Faculty of Veterinary Medicine, Benha University, Toukh, Egypt.
Department of Anatomy and Embryology, Faculty of Veterinary Medicine, Benha University, Egypt.
Vet Anaesth Analg. 2018 Mar;45(2):175-182. doi: 10.1016/j.vaa.2017.09.039. Epub 2017 Nov 7.
Description of an ultrasound (US)-guided technique for retrobulbar nerve blockade in dromedary (Camelus dromedarius) cadavers.
Prospective experimental cadaveric study that was carried out in three phases: phase I: anatomical dissection and development of US-guided technique; phase II: methylene blue (MB) injection; phase III: contrast medium (CM), US-guided injections with computed tomography (CT) control.
A total of 36 orbits from 18 heads were obtained from 18 dromedary cadavers.
Phase I: anatomical dissections were carried out bilaterally, using two heads to determine needle site placement. Phase II: a US-guided, lateral, in-plane approach using one of three volumes of MB (3, 6, or 9 mL) was evaluated in six heads (four orbits per volume tested) to establish the ideal injection volume. Injections of MB that strongly stained all retrobulbar nerves were considered successful, whereas insufficient MB volumes resulted in weak or no nerve staining. Phase III: US-guided retrobulbar injection with CM was carried out using 20 orbits. Computed tomography was performed after each injection trial to determine the accuracy of needle placement and CM dispersal. An injection was judged to be successful when the CT images revealed that the needle was located within the retractor bulbi muscle cone and the CM reached the target nerves at the orbitorotundum and the optic foramina.
Only injection of 9 mL of MB stained the target nerves sufficiently, whereas there was no or only weak staining with 3 and 6 mL, respectively. Therefore, 9 mL of CM was used for the US-guided injections in phase III. Subsequent CT scans revealed satisfying CM distribution within the ocular muscle cone in 18 of 20 cases (90% success rate).
US-guided retrobulbar injection in dromedary cadavers is feasible. Further research is required to assess its practicality and usefulness in vivo.
描述一种在单峰驼（骆驼属单峰驼）尸体上进行超声引导下球后神经阻滞的技术。
前瞻性实验性尸体研究，分三个阶段进行：第一阶段：解剖并开发超声引导技术；第二阶段：注射亚甲蓝（MB）；第三阶段：注射造影剂（CM），在计算机断层扫描（CT）控制下进行超声引导注射。
从18具单峰驼尸体上获取了18个头的共36个眼眶。
第一阶段：双侧进行解剖，使用两个头来确定进针部位。第二阶段：在六个头（每个测试体积的MB注射四个眼眶）中评估使用三种体积（3、6或9毫升）的MB之一进行超声引导下的外侧平面内进针方法，以确定理想的注射体积。能使所有球后神经强烈染色的MB注射被认为是成功的，而MB体积不足则导致神经染色较弱或无染色。第三阶段：使用20个眼眶进行超声引导下的球后CM注射。每次注射试验后进行计算机断层扫描，以确定进针位置和CM扩散的准确性。当CT图像显示针位于眼球退缩肌圆锥内且CM到达眶圆孔和视神经孔处的目标神经时，注射被判定为成功。
仅注射9毫升MB能充分使目标神经染色，而分别注射3毫升和6毫升时无染色或仅有微弱染色。因此，在第三阶段的超声引导注射中使用9毫升CM。随后的CT扫描显示，20例中有18例（成功率90%）CM在眼肌圆锥内分布良好。
在单峰驼尸体上进行超声引导下球后注射是可行的。需要进一步研究以评估其在体内的实用性和有效性。
