Surgical options in experimental porcine model for endovascular training in complex vascular lesions

Abstract

We describe a new, elegant, two-phase, microsurgical method that minimizes the surgical preparation time for different complex vascular lesions in a swine model. In the first phase, the model is prepared microsurgically in the experimental laboratory using arterial or/and venous grafts. In the second phase, the model is implanted in the experimental animal. This two-fold method allows for increasing the complexity and accuracy of the model while reducing preparation time on the day of the training session.

Keywords: Endovascular training; aneurysm model; animal experimentation; arteriovenous fistula model; experimental surgery.

Figure 1.

displays a schematic drawing (image a) and a surgical picture (image b) of a cervical dissection and exposure of the neurovascular bundle of the neck. This is the site of implantation of the models. It includes the common carotid artery, the vagosympathetic trunk and the internal jugular vein. Of greater thickness, the external jugular vein is also exposed in the dissection.

Figure 2.

illustrates the construction of a complex wide-neck bifurcation aneurysm. The purpose of this figure is to display schematically how we perform the aneurysm reconstruction represented in Figure 3. For the preparation of this complex model, we require the use of two arterial grafts and one venous graft (image 2a). The first arterial graft is used as a recipient of the second arterial graft and part of the venous graft. For its subsequent implementation, two oblique cuts are made at each end, as well as two lateral slits (fish mouth). In this same artery two lateral slits are made for the suturing of the second arterial graft. In the second arterial graft, two oblique cuts and two lateral slits are made to facilitate anastomosis to the first graft. However, at the proximal end of this second graft additional slits are made, the length of which determines the neck of the aneurysm and the location of the base on one or both branches. In other words, the shorter the upper groove in relation to the lower one, the lower the aneurysm will be in relation to this vessel. To carry out the anastomosis, the usual technique is followed, in which anchorage is made at the margins and a continuous suture is put under tension once all points have been correctly passed (images 2b and 2c).

Figure 3.

Image 3a corresponds to three-dimensional reconstruction of a typical aneurysm at the bifurcation of the middle cerebral artery. Note the amplitude of the neck of the aneurysm and its preferential relationship with one of the two branches. In image 3b the created model is shown, ready for later implantation in the experimental animal. Image 3c shows a surgical view of the model just after implantation and image 3d corresponds to an angiographic image of the final implanted model. Note the model has all the angiographic characteristics of the desired aneurysm. The created aneurysm has a wide base of implantation with a preferential relationship to one of the branches. Image 3e shows an image of the practice in which partial embolization of the aneurysm is observed. Note the two clips placed distally to the first end-to-side anastomosis and proximally to the second end-to-side anastomosis to occlude the carotid artery.

Figure 4.

The figure shows the construction of two wide-neck aneurysms in a cavernous carotid artery model. The object of the model is to represent two aneurysms in an artery with the precise curvature typical of the cavernous artery. This requires the use of one arterial graft and one venous graft (image 4a). The arterial graft is used as a recipient of the venous graft. For its subsequent implementation in the carotid artery, two oblique cuts with lateral slits (fish mouth) are made at each end. In this same artery, two lateral slits are made for the implantation of the venous grafts. The size of these lateral slits determines the neck of the aneurysm and the size of the selected vein dictates the size of the aneurismal dome. To carry out the anastomosis, the usual technique is followed, anchoring first at the margins and tensing a continuous suture once all points have been correctly passed (images 4b and c). Image 4d corresponds to a typical angiography of a wide-neck aneurysm of the intracavernosal carotid artery. In image 4e the created model is shown, ready for later implantation in the experimental animal. Image 4f shows a surgical image of the model after implantation.

Figure 5.

The figure shows the construction of an arteriovenous fistula. This requires the use of one arterial graft and one venous graft (image 5a). As per protocol, two oblique cuts with lateral slits (fish mouth) are made at each end. For the preparation of the model, one end of the vein is occluded. A slit that matches the diameter of the artery to be anastomosed is made (image 5b). The arterial graft is connected laterally to the venous graft for subsequent implementation on the carotid artery and internal jugular vein (image 5c). To carry out the anastomosis, the usual technique is followed: anchorage at the margins and tension of a continuous suture once all tissue has been correctly passed. Image 5d shows a surgical view of the arteriovenous model after implementation.