The authors thank Olgica Beslac and Kay Nettelbeck for their excellent support and technical assistance during the peri-operative phase and Alessandra Bergadano, DVM, PhD, for the dedicated supervision of the long-term animal health.

All veterinary care was performed in accordance with the institutional guidelines (all experiments were approved by the Local Committee for Animal Care of the Canton Bern, Switzerland (BE 108/16)) and conducted under supervision of a board-certified veterinarian anesthesiologist. The ARRIVE guidelines and the 3R principles were strictly followed17,18.
NOTE: House all animals at a room temperature of 22&#8210;24 Celsius (&#176;C)&#160;a...

Our study demonstrates the feasibility of creating a true bifurcation aneurysm model with different wall conditions in rabbits. Overall, 14 female New Zealand White rabbits with a mean weight of 3.7 &#177; 0.09 kg and mean age of 112 &#177; 3 days were included in the study. 85.72% of all aneurysms remained patent during a follow-up at 28 days. Two animals died prematurely (12.5% mortality).
Previous studies suggested a variety of extracranial aneurysm models to analyze the management of endov...

Subarachnoid hemorrhage resulting from intracranial aneurysm (IA) rupture&#160;can effectively be controlled by either endovascular or microsurgical occlusion techniques1,2,3,4. Different endovascular therapies, to overcome the main limitation of IA recurrence after coiling, gained importance over the past decades generating an increased need of testing endovascular devices. To test these novel treatment approaches, appropriate animal models that respect rheological properties, hemodynamics and aneurysm wall conditions are highly warranted5,6,7. In this context, clinical as well as preclinical studies have already revealed the important role of aneurysm wall conditions regarding aneurysm rupture and recurrence after occlusion, especially focusing on the loss of mural cells7,8,9.
So far, experimental aneurysms in rabbits have most often been created either by elastase incubated common carotid artery (CCA) stumps or venous pouches sutured into an artificial CCA bifurcation.10,11,12,13,14,15,16 Thus, a true arterial pouch bifurcation model has never been described.
The aim of this study was to design a safe, fast, and standardized technique for microsurgical creation of bifurcation aneurysms with different wall conditions in a rabbit model (Figure 1). This was achieved by suturing non-modified and modified arterial pouches into an artificial created bifurcation of both CCAs.

<table>
	<tbody>
		<tr>
			<td>3-0 resorbable suture</td>
			<td>Ethicon Inc., USA</td>
			<td>VCP428G</td>
			<td></td>
		</tr>
		<tr>
			<td>4-0 non-absorbable suture</td>
			<td>B. Braun, Germany</td>
			<td>G0762563</td>
			<td></td>
		</tr>
		<tr>
			<td>6-0 non-absorbable suture</td>
			<td>B. Braun, Germany</td>
			<td>C0766070</td>
			<td></td>
		</tr>
		<tr>
			<td>9-0 non-absorbable suture</td>
			<td>B. Braun, Germany</td>
			<td>G1111140</td>
			<td></td>
		</tr>
		<tr>
			<td>Adrenaline</td>
			<td>Amino AG</td>
			<td>1445419</td>
			<td>any generic</td>
		</tr>
		<tr>
			<td>Amiodarone</td>
			<td>Helvepharm AG</td>
			<td>5078567</td>
			<td>any generic</td>
		</tr>
		<tr>
			<td>Anesthesia machine</td>
			<td>Dr&#228;ger</td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Aspirin</td>
			<td>Sanofi-Aventis (Suisse) SA</td>
			<td>622693</td>
			<td>any generic</td>
		</tr>
		<tr>
			<td>Atropine</td>
			<td>Labatec Pharma SA</td>
			<td>6577083</td>
			<td>any generic</td>
		</tr>
		<tr>
			<td>Bandpass filter blue</td>
			<td>Thorlabs</td>
			<td>FD1B</td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Bandpass filter green</td>
			<td>Thorlabs</td>
			<td>FGV9</td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Bipolar forceps</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Bicycle spotlight</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Biemer vessel clip (2 x)</td>
			<td>B. Braun Medical AG, Aesculap, Switzerland</td>
			<td>FD560R</td>
			<td>temporary</td>
		</tr>
		<tr>
			<td>Bispectral index (neonatal)</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Blood pressure cuff (neonatal)</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Clamoxyl</td>
			<td>GlaxoSmithKline AG</td>
			<td>758808</td>
			<td>any generic</td>
		</tr>
		<tr>
			<td>Dexmedetomidine</td>
			<td>Ever Pharma</td>
			<td>136740-1</td>
			<td>any generic</td>
		</tr>
		<tr>
			<td>Electrocardiogram electrodes</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Elastase</td>
			<td>Sigma Aldrich</td>
			<td>45125</td>
			<td>any generic</td>
		</tr>
		<tr>
			<td>Ephedrine</td>
			<td>Amino AG</td>
			<td>1435734</td>
			<td>any generic</td>
		</tr>
		<tr>
			<td>Esmolol</td>
			<td>OrPha Swiss GmbH</td>
			<td>3284044</td>
			<td>any generic</td>
		</tr>
		<tr>
			<td>Fentanyl (intravenous use)</td>
			<td>Janssen-Cilag AG</td>
			<td>98683</td>
			<td>any generic</td>
		</tr>
		<tr>
			<td>Fentanyl (transdermal)</td>
			<td>Mepha Pharma AG</td>
			<td>4008286</td>
			<td>any generic</td>
		</tr>
		<tr>
			<td>Fluoresceine</td>
			<td>Curatis AG</td>
			<td>5030376</td>
			<td>any generic</td>
		</tr>
		<tr>
			<td>Fragmin</td>
			<td>Pfizer PFE Switzerland GmbH</td>
			<td>1906725</td>
			<td>any generic</td>
		</tr>
		<tr>
			<td>Glyco</td>
			<td></td>
			<td></td>
			<td>any generic</td>
		</tr>
		<tr>
			<td>Heating pad</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Isotonic sodium chloride solution (0.9%)</td>
			<td>Fresenius KABI</td>
			<td>336769</td>
			<td>any generic</td>
		</tr>
		<tr>
			<td>Ketamine</td>
			<td>Pfizer</td>
			<td>342261</td>
			<td>any generic</td>
		</tr>
		<tr>
			<td>Laboratory shaker</td>
			<td>Stuart</td>
			<td>SRT6</td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Lidocaine</td>
			<td>Streuli Pharma AG</td>
			<td>747466</td>
			<td>any generic</td>
		</tr>
		<tr>
			<td>Longuettes</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Metacam</td>
			<td>Boehringer Ingelheim</td>
			<td>P7626406</td>
			<td>any generic</td>
		</tr>
		<tr>
			<td>Methadone</td>
			<td>Streuli Pharma AG</td>
			<td>1084546</td>
			<td>any generic</td>
		</tr>
		<tr>
			<td>Microtubes</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Micro needle holder</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Midazolam</td>
			<td>Accord Healthcare AG</td>
			<td>7752484</td>
			<td>any generic</td>
		</tr>
		<tr>
			<td>Needle holder</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>O2-Face mask</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Operation microscope</td>
			<td>Wild Heerbrugg</td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Papaverine</td>
			<td>Bichsel</td>
			<td></td>
			<td>any generic</td>
		</tr>
		<tr>
			<td>Prilocaine-lidocaine creme</td>
			<td>Emla</td>
			<td></td>
			<td>any generic</td>
		</tr>
		<tr>
			<td>Propofol</td>
			<td>B. Braun Medical AG, Switzerland</td>
			<td></td>
			<td>any generic</td>
		</tr>
		<tr>
			<td>Pulse oxymeter</td>
			<td></td>
			<td></td>
			<td>any generic</td>
		</tr>
		<tr>
			<td>Rectal temperature probe (neonatal)</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Ropivacaine</td>
			<td>Aspen Pharma Schweiz GmbH</td>
			<td>1882249</td>
			<td>any generic</td>
		</tr>
		<tr>
			<td>Scalpell</td>
			<td>Swann-Morton</td>
			<td>210</td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Small animal shaver</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Smartphone</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Soft tissue forceps</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Soft tissue spreader</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Stainless steel sponge bowls</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Sterile micro swabs</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Stethoscope</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Straight and curved micro-forceps</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Straight and curved micro-scissors</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Straight and curved forceps</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Surgery drape</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Surgical scissors</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Syringes 1 ml, 2ml and 5 ml</td>
			<td></td>
			<td></td>
			<td>any other</td>
		</tr>
		<tr>
			<td>Tris-Buffer</td>
			<td>Sigma Aldrich</td>
			<td>93302</td>
			<td>any generic</td>
		</tr>
		<tr>
			<td>Vascular clip applicator</td>
			<td>B. Braun, Germany</td>
			<td>FT495T</td>
			<td></td>
		</tr>
		<tr>
			<td>Vein and arterial catheter 22 G</td>
			<td></td>
			<td></td>
			<td>any generic</td>
		</tr>
		<tr>
			<td>Vitarubin</td>
			<td>Streuli Pharma AG</td>
			<td>6847559</td>
			<td>any generic</td>
		</tr>
		<tr>
			<td>Yasargil titan standard clip (2 x)</td>
			<td>B. Braun Medical AG, Aesculap, Switzerland</td>
			<td>FT242T</td>
			<td>temporary</td>
		</tr>
	</tbody>
</table>

arterial pouch microsurgical bifurcation aneurysm model in the rabbit

Endovascular treatment for intracranial aneurysms gained importance over the past decades, consequently there is an increased need of testing endovascular devices. Animal models respecting rheological, hemodynamic and aneurysm wall conditions are highly warranted. Therefore, the aim of the present study was to design a novel standardized and reproducible surgical technique to create autologous arterial pouch bifurcation aneurysms with non-modified and modified wall conditions in rabbits.
Bifurcation aneurysms were created by end-to-side anastomosis of the right on the left common carotid artery, both serving as parent arteries for the arterial pouch, which was microsurgically sewn on. Grafts were taken from the proximal right common carotid artery, either for the control (n = 7, immediate autologous re-implantation) or modified (n = 7, incubated with 100 international units elastase for 20 minutes before autologous re-implantation) group. Pouch and parent artery patency were controlled by fluorescence angiography immediately after creation. At follow-up (28 days), all rabbits underwent contrast enhanced magnetic resonance angiography and fluorescence angiography followed by aneurysm harvesting, macroscopic and histological evaluation.
A total of 16 female New Zealand White rabbits were operated upon. Two animals died prematurely. At follow-up, 85.72% of all aneurysms remained patent. Both groups revealed an increase in aneurysm size over time; this was more pronounced in the control group (6.48 &#177; 1.81 mm3 at time of creation vs. 19.85 &#177; 6.40 mm3 at follow-up, p = 0.037) than in the modified group (8.03 &#177; 1.08 mm3 at time of creation vs. 20.29 &#177; 6.16 mm3 at follow-up, p = 0.054).
Our findings demonstrate the adequacy of this new rabbit model which allows for the creation of bifurcation aneurysms with different wall conditions in a microsurgical approach. Given the excellent long-term patency and the property of aneurysm growth over time, this model may serve as an important tool for preclinical evaluation of novel endovascular therapies.

Following a pilot series of seven animals, totally 16 animals were included in the experimental protocol. Two animals died prematurely and were therefore excluded from the final analysis (12.5% mortality). Calculated on 14 animals, immediate aneurysm patency rate during fluorescence angiography was 71.43% in both, the control and modified group. Four aneurysms had to be reopened with consecutive thrombus evacuation and after a repeated fluorescence angiography there was a documented patency in all cases (100%). Aneurysm ...

Watch this Scientific Journal Video about Arterial Pouch Microsurgical Bifurcation Aneurysm Model in the Rabbit at JoVE.com

Arterial Pouch Microsurgical Bifurcation Aneurysm Model in the Rabbit

Developing and testing endovascular devices for intracranial aneurysm treatment is still of great importance. Most aneurysm models used today miss either the important characteristics of an arterial degenerated wall or the hemodynamics of a true bifurcation. Therefore, we aimed to design a novel arterial pouch bifurcation model in rabbits.

Endovascular treatment for intracranial aneurysms gained importance over the past decades, consequently there is an increased need of testing endovascular ...

As the development and testing of endovascular devices in intracranial aneurysm treatment is still greatly needed. We have designed a novel arterial pouch bifurcation model in rabbits. This model uses a single, highly standardized and easily reproducible microsurgical technique to create a autologous material pouch bifurcation aneurysms with modified and non-modified wall conditions in rabbits.After confirming a lack of response to pedal reflex in an anesthetized adult rabbit, make a median skin incision from the manubrium sterni to the level of the larynx, and use a scalpel, surgical scissors, and forceps to sharply dissect the skin and soft tissue. Using micro forceps and surgical scissors, enter the anterior upper ridge of the sternocleidomastoid muscle immediately on the left side by blunt dissection. And macroscopically perform a blunt preparation to carefully distally separate the left common carotid artery from the vagal nerve to avoid laryngeal paresis.Administer 40 milligrams per milliliter of papaverine locally into the artery and position the papaverine soaked artery below the autologous muscle tissue to protect the vessel from dehydration under the light of the surgical microscope. Switch sides and perform the same dissection on the right side of the animal as just demonstrated. When the right common carotid artery has been isolated inject 500 international units per kilogram of heparin systemically via a venous ear catheter.After tightening the six zero ligature, use a temporary vessel clip to clamp the right common carotid artery as far distally as possible to avoid endothelial damage, to create a long vessel segment for irrigation to prevent thrombogenesis. To harvest the pouch, cut the distal vessel to the four zero nonabsorbable ligature. Then cut the vessel distal to the 6-0 non-absorbable ligature.Meticulously clean the arterial pouch of all soft tissue and use a vessel clip to measure the length, width, and depth of the pouch. If a pouch degradation is needed, pre-incubate the cleaned pouch with 100 units of porcine elastase dissolved in five milliliters of Tris buffer at room temperature for 20 minutes. For further preparation of the common carotid artery, place two micro swabs directly beneath the common carotid artery to allow the vessel to be moved superficially and place an additional micro swab with a blue padding under the left artery at the distal third for better visualization of the artery.Change sides to access the left side of the animal and use micro scissors and forceps to make a two millimeter fish mouth incision on the proximal side of the right common carotid artery. Use the second temporary vessel clip to clamp the left distal common carotid artery and clamp the proximal left common carotid artery with two additional temporary vessel clips. When all of the clamps have been placed, liberate the distal third of the left common carotid artery completely from the soft tissue and perform an arteriotomy.Now flush the recipient vessel with heparinized saline and liberate the complex from a adventitia, then suture the right common carotid artery to the left common carotid artery. Transfer the arterial pouch from the heparinized saline solution into the surgical field where the bifurcation is planned. While keeping all of the aspects of the vessel complex hydrated with a continuous saline irrigation, suture the pouch to the vessel, and then remove all of the temporary vascular clamps in stepwise manner.When all of the clamps have been removed, administer one milliliter of fluorescein intravenously to perform fluorescence angiography of the vessel complex. Then close the operative situs according to standard protocols. In this experimental analysis, animals with aneurysms induced by either the vital or elastase pouch methods demonstrated an increase in aneurysm size over time.The average duration of the surgical procedure for the control group was 164 plus or minus 10 minutes compared to 201 plus or minus 13 minutes for the modified group. An average of 24 plus or minus one interrupted sutures was needed to create aneurysms in the controlled group, while 25 plus or minus two stitches were required in the elastase group. Measurements can then be performed by using three dimensional reconstructions of the MR imaging and detailed histological analysis.A careful separation of the common carotid artery from the vagal nerve is essential for avoiding postoperative complications. To avoid thrombogenesis, keep the vessel and arterial pouch complex hydrated. Given the excellent patiency achieved with aneurysm growth over time, this model may serve as an important tool for the preclinical evaluation of novel endovascular devices.

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Research

JoVE Journal

Neuroscience

2.2K visualizações.  Kantonsspital Aarau. As the development and testing of endovascular devices in intracranial aneurysm treatment is still greatly needed. We have designed a novel arterial pouch bifurcation model in rabbits. This model uses a single, highly standardized and easily reproducible microsurgical technique to create a autologous material pouch bifurcation aneurysms with modified and non-modified wall conditions in rabbits.After confirming a lack of response to pedal reflex in an anesthetized adult rabbit, make a m...