The Helsinki Rat Microsurgical sidewall aneurysm model. The following video gives in depth descriptions of most important features of the rat Microsurgical sidewall aneurysm model developed at the Department of Neurosurgery University Hospital, Helsinki, Finland. We present step by step procedural instructions, information on necessary equipment, and discuss important and anatomical and surgical details for successful microsurgical creation of a sidewall aneurysm in the rat hardware and consumables.
The small animal surgery room needs to be kept quiet, aseptic, and the room temperature maintained at 23 plus minus three degree. The following minimal equipment is needed to perform the experimental aneurysm surgery. A tabletop microsurgical microscope is ideally equipped with an assistance scope and digital microscope camera.
Non-porous reusable operating surface and cleanable instrument surface is used to protect the laboratory bench consumables such as skin disinfectants, physiological cell line, smaller and larger. Gold swaps and suture material including nine zero micro sutures. A five zero non-absorbable and the free zero absorbable suture are prepared.
The following standard surgical instruments are needed, surgical scissors, tissue forceps, soft tissue spreader, or self retaining retractor, and two mosquito surgical clamps. The basic microsurgical instrument set includes curved microneedle holder, one curved and two straight micro forceps and the straight or curved micro scissor. Keep the microsurgical instruments in a kidney dish filled with sterile cell line to keep the instrument non-stick and clean.
During surgery. The kidney dish is padded with a rubber mat or a surgical glove to prevent damage to the tips of the micro instruments. In addition, a vascular clip applicator and three temporary vascular atraumatic clamps are needed.
It is important that the clamps used have a low closing power to prevent injury to the very thin wall of the rat aorta. We also prepare a ruler with half millimeter scale bars, a small colored rubber pad and a short blunt needle anesthetized rat by weight adapt subcutaneous injection of meine hydrochloride, 0.4 milligram per kilogram and intraperitoneal injection of ketomine hydrochloride 60 milligram per kilogram test for the lack of a two pinch reflex to confirm that rat is fully anthesis prior to skin and session. Monitor the death of the anesthesia every 15 minutes during surgery by following respiratory rate, heart rate, and reaction to noxious stimulation.
Subcutaneous injection of buprenorphine 0.03 milligram per kilogram is given for postoperative and analgesia and repeated if necessary. Every 12 hours graft harvesting from the Jurassic aorta. Place the rat in a supine position, immobilize both front and hind pulse with surgical tape without applying stretch or compression to the skin.
Apply a noxious two pinch stimulus to confirm that the rat is fully unresponsive before open up the thoracic cavity. Immediately after opening the thoracic cavity, the rat is sacrificed by overdosing with intracardiac injection of ketamine hydrochloride, and the lungs are mobilized to the right side of the heart. Pulmonary trunk, left subclavian vein, left cranial vein, CVA and ATUs vein interfere with the harvest of the proximal thoracic aorta coddle to the prominent veins.
There is a good entry point to start the dissection of the descending thoracic aorta using micro scissors and micro forceps. Trace the thoracic aorta back from the dorsal wall of the tox upwards to the aortic arch by gentle blunt retraction and dissection with the mosquito surgical clamp, the winds are clamped and then cut with scissors. The clamps are maintained on the wanes and used as retractor to expose the underlying aortic arch.
A ligature is placed just above the first intercostal artery leaving the aorta. The descending aorta is then cut just below the left subclavian artery and then below the ligature. Dreaming can be done in order to get the perpendicular standardized aneurysm geometry, or if needed to get a specific angle between the axis of the aneurysm and the aorta.
The graft is measured in its width and length. Harvested grafts can either be immediately transplanted into recipient rats or further processed to achieve a decellularization of the graft.Wall. Decellularized grafts can be stored at minus four degrees Celsius until reimplantation.
At the later date. The decellularization of the aneurysm wall has been shown to predispose the aneurysm to enlarge aneurysm creation After the animal has been anesthetized, clipped the fur from the surgical site and cleaned the skin with a suitable disinfectant, placed the rat in a supine position immobilize both front and hind pulse with a surgical tape without applying stretch or compression to the skin, bend their back with a thick marker or ery pen by placing it under the lumbar region of the back. It is important to obtain as much lumbar spine lordosis as possible in order to improve retroperitoneal exposure and access to the infrarenal aorta which facilitates microsurgical anastomosis test for the lack of a two pinch reflex to confirm that rat is fully and ized prior to skin incision.
After midline incision, the small intestines and the prominent saum are moved to the right or the left. The ligament in between the small intestine and the de descending colon is cut in cranial direction. To allow wider exposure of the dorsal body wall, a self retaining retractor is placed to hold the bowels apart.
The ideal location of endocyte aneurysm anastomosis is found at the level between the renal and iliolumbar veins. The abdominal aorta lies retroperitoneal embedded in fat tissue during dissection. Particular attention has to be paid to the paired, almost transparent ureter and testicular vessels.
A further retraction of intestines is needed. Larger ghost swabs may be used. The ventral surface of the dorsal body wall is covered with a thin peral peritoneum.
Once this is opened, the aorta can be visualized just underneath during careful sharp and blunt dissection of the abdominal aorta. Only the advia should be grasped to avoid damage to the vessel wall. In frequently small lumbar arteries arise as segmental vessel from the dorsal surface of the abdominal aorta and interfere with preparation.
Use of curved micro forceps can facilitate ligature. Placement in the depth ligation and cutting of the vessel is needed to avoid retrograde oozing. During aneurysm suturing, a colored rubber pad is put underneath the abdominal aorta and upholstered with a small cause swab loose connective tissue and AIA is removed at the level of the planned anastomosis site.
The abdominal aorta is clamped distal to the anastomosis first, then proximal. This ensures a firm filling of the vessel and facilitates subsequent artery otomy. The artery otomy is performed using either straight or curved micro scissors.
A micro forceps holds up a very small piece of the vessel wall to cut out elliptical shape. The artery is flushed thoroughly with cell line in both directions using a blunt tipped needle. The first two sutures of this end to side anastomosis are placed at the proximal and distal end of the artery otomy.
At that point, suturing is performed either as continuous or interrupted sutures. If interrupted sutures is chosen, then the backside nine o'clock suture is placed.First. Grasping of the vessel wall with the micro forceps is avoided.
Whenever possible, make sure that each suture is placed through all layers of the we wall. Subsequent sutures can be spaced apart starting adjacent to the very first suture weyl walls respectively. AIA is grasped cautiously and is squeezing or grasping of the intima is avoided.
When the back wall is finished, the endoluminal part of the anastomosis is checked. For misplaced sutures, the same procedures in the same order are now performed on the front side of the anastomosis, especially the first of a total of three knots. Procedure should be firm but not too tight.
After the endocytosis is completed, the site is rinsed with cell line and the distal clamp removed first to allow for backflow. If obvious bleeding occurs from backflow, an extra stitch may be needed. In case of minor oozing, hemostasis can be achieved with gentle pressure over the bleeding side.
Using a small piece of ghost swap. The proximal vascular clamp is then removed. The anastomosis side rinsed once more and the remaining ends of the ligature at the aneurysm doom cut off distal abdominal artery patency is assessed through the direct milking test.
The plastic sheet and the small ghost swab underneath are removed. The pulsating blood will within the created aneurysm is clearly visible. Suture lines around anastomosis can be covered with small pieces of adipose tissue or pongo stand for additional hemostasis.
If small oozing is still present, the soft tissue spreader and gauze swabs are removed. In conclusion, the Helsinki rat aneurysm model is a fast, affordable, and consistent method to create experimental aneurysms that are standardized by means of size, shape, and geometric configuration of the aneurysm in relation to the parent artery.
