This method can help answer key questions about how to set up a life training module for microvascular head and neck reconstruction. The main advantage of this technique is that it facilitates a de froment of microvascular reconstructive surgery skills for beginner surgeons. Begin by using a laryngoscope to expose the vocal cords through the mouth of a 25 to 30 gram female Yorkshire pig and spraying the cords with two puffs of 2%lidocaine topical solution to prevent intubation-induced laryngospasm.
Intubate with a 6.5 millimeter tube. And use a syringe to inflate the tube cuff with three to five milliliters of air. After ensuring that the tracheal tube is in the proper position, apply ointment to the animal's eyes.
And protect the eyes with a cover patch. Next, use a 1%iodine-based scrub solution to disinfect the neck and abdominal wall. And use a number 23 blade to make a vertical midline anterior neck incision to the sternum.
Dissect the strap muscles. And use Kelly tissue scissors and a Lahey retractor to pull back the muscles laterally to expose the trachea from the first ring to the thoracic inlet. Expose the common carotid artery in the internal jugular vein for the anastomosis and use a number 11 blade to create a one centimeter window in the second or third cartilage.
Then look for the endotracheal tube through the tracheal defect and confirm the presence of continuous aeration through the tube. To perform a superior epigastric artery perforator flap harvest, use a surgical marking pen to design a flap on the upper abdomen and use a number 23 scalpel to create a four by three centimeter elliptical skin incision through the anterior sheath of the abdominal wall on the medial side of the flap. While holding the fascia by the Allis, elevate the flap from the rectus abdominis muscle sheath to locate the perforators going to the skin flap.
Blunt dissect the exposed muscle tissue. And follow the perforators to the superior epigastric vessels. Use a number 23 scalpel to make a lateral skin incision in the flap.
And superiorly clamp the superior epigastric vessels and venae comitantes with a haemostat. Then use the Kelly tissue scissors to cut above the haemostat, and ligate the vessel below the haemostat with a three-oh suture to allow removal of the haemostat. For anastomosis of the vessel use a surgical loupe to clamp the carotid artery with two haemostats one to two centimeters apart.
Use microscissors to cut between the haemostats. And tie the superior part of the vessel with a double suture to prevent leakage. Using the double clamp without the frame between the carotid and flap arteries, use a 10-oh simple full thickness interpreted suture to place the first two stay sutures approximately 120 degrees apart around the circumference of the vessel and two to three stitches between the stay sutures.
Release the clamp and check for leakage. If there is no backflow from the venae comitantes, create another anastomosis for the internal jugular vein and the venae comitantes as just demonstrated. Using a syringe equipped with an 18 gauge needle, prick the skin to confirm flap viability.
If a drop of blood appears, use a three-oh suture to close the tracheal window with the muscle fascia of the superior epigastric artery perforator flap. Then exteriorize and suture a skin panel of the flap to the cervical midline skin incision and close the abdominal skin incision. At the end of the procedure, return the pig to the prone position and allow the animal to recover without other animals.
Deliver Ringer's lactate at a 150 milliliters per hour rate until the animal has fully recovered, and administer 0.3 milligrams buprenorphine for analgesia. When the animal is recumbent begin intramuscular amoxicillin clavulanate and meloxicam for one week, checking the donor site and the flap at the reconstruction site daily for healing progression. In these representative studies the mean ischemia time was 50 minutes with the procedure time decreasing as the model was repeated.
The mean harvest time of the six pigs was 55 minutes and no morbidity was observed at the donor site in this module. The mean pedicle size of the flaps was 10 centimeters, similar to that observed in the human head and neck. The mean artery diameter was 4.4 millimeters and the mean vain diameter was 5.75 millimeters, both larger than the human average of two millimeters for both vessels while still being able to simulate human anatomy.
The skin paddle size ranged from 25 to 40 centimeters squared without a significant effect on the flap failure. While attempting this procedure it's important to remember to approach the perforators carefully and to ensure a good venous backflow. After its development this technique paved the way for researchers in the field of trachea reconstruction to explore the use of fascia for trachea defects, and for determining an appropriate safe flap size without collapsing the airway.
Don't forget that performing a trachea reconstruction can be extremely dangerous and that precautions such as making sure the airway is patent and intact should always be taken while performing this procedure.
