Feasibility of thoracoscopic attenuation of the azygos vein as a model for portoazygos shunts: A canine cadaveric study

Abstract

Objective To evaluate the feasibility of thoracoscopic placement of three vascular attenuation devices by using the azygos vein as a model for portoazygos (PA) shunts and to describe the approach for thoracoscopic placement of these attenuation devices in small breed dogs. Study design Randomized, prospective, cadaveric study. Animals Cadavers of 10 adult small breed dogs. Methods Cadavers were placed in sternal recumbency with left dorsolateral obliquity, and three thoracoscopic ports were established in the right hemithorax at the mid‐10th intercostal space and dorsal third of the ninth and 11th intercostal spaces. The caudal azygos vein was thoracoscopically isolated along three adjacent segments bordered by four intercostal arteries, beginning just cranial to the first intercostal artery visualized cranial to the diaphragm. Three attenuation devices including coated cellophane, uncoated cellophane, and a 5‐mm ameroid constrictor were thoracoscopically placed around one segment in each dog. Minor port access modifications were required to improve working space and triangulation in three dogs. Ability to successfully place the device, time required for placement, endoscopic clip configuration, and complications associated with placement were recorded. Results Median dog weight was 7.7 kg (range, 1.8‐11). All attenuation devices were successfully placed thoracoscopically in all cadavers. No difference was detected in time required for placement between the ameroid constrictor and coated and uncoated cellophane (range, 2.3‐33.8 minutes, P = .8). Conclusion Ameroid constrictors and thin film bands were consistently placed via thoracoscopy around the caudal azygos vein of small breed dogs. Clinical significance These results justify further investigation of thoracoscopic PA shunt attenuation in affected dogs.

Laparoscopic attenuation of a congenital extrahepatic portosystemic shunt in a dog—a thin-film banding for splenophrenic shunt: A case report

“…It is also easily introduced through the port and has no concerns about premature closure occurring with ARC occasionally that results from vascular kinking or collapse due to the weight of an implant ( 10 , 12 , 17 ). Although the author has been using TFBs in laparoscopic PSS attenuations, ARCs could be used in laparoscopic attenuation; however, there would be a need to use a larger port for ARC introduction and dropping ARC device or key in the body cavity could be bothersome during placement sometimes ( 19 ). Moreover, a tendency was reported that ARCs in larger diameters are at risk of incomplete occlusion ( 20 ).…”

Laparoscopic portosystemic shunt attenuation in 20 dogs (2018‐2021)

“…Possible intraoperative complications include the necessity of converting to an open approach when the shunt cannot be located during laparoscopic exploration and intraoperative hemorrhage 27 . A recent cadaveric study described the feasibility of portoazygos shunt attenuation via a thoracoscopic approach, however, the outcomes following LPSSA in a larger number of dogs with a CEPSS has not been described 28 …”

“…27 A recent cadaveric study described the feasibility of portoazygos shunt attenuation via a thoracoscopic approach, however, the outcomes following LPSSA in a larger number of dogs with a CEPSS has not been described. 28 The aims of this study were to determine the success of LPSSA in dogs with a CEPSS, describe the laparoscopic approach in relation to the shunt configuration/location, and evaluate complications and outcomes. We hypothesized that LPSSA can be used successfully in dogs with a CEPSS.…”