Materials and methods
A small flight briefcase (N = 1, $ 50.20, reusable) is the simulator casing. It can be carried easily and, when opened, is arranged from the surgeon’s viewpoint as in the operating theatre (Figure 1A). An oblique lint roller tube (N = 1, $ 0.60) is secured on a plywood sheet (N = 1, $ 9.70, reusable) as the simulator skeleton (Figure 1B). The tube is in a sponge working field. The root and ascending aorta are replicated by a rolled and glued foam sheet with two heat-shrink sleeving tubes (N = 2, $ 0.33, non-reusable), replicating the coronary arteries, attached to it (Figure 2). The aortic valve and the commissures are reproduced by a condom (N = 1, $ 0.70, non-reusable) and a ‘press-and-seal’ sandwich bag plastic sealer (N = 60, $ 2.6, reusable) respectively. The pattern of aortic root and the measurements are mapped on the foam sheet (N = 1, $ 0.83, non-reusable). For example, to design a 4 cm aortic root simulator the following measurements need to be taken into account: Foam sheet width: 13.6 cm, Profile height (distance between the upper and lower lines): 2.2 cm, Divide upper line into three segments of 4.5 cm, Divide the lower line into two segments of 4.5 cm in the middle and one segment of 2.25 cm on either side of the middle segments, six length of 3.2 cm press-and-seal to form the annulus in zigzag pattern connecting the upper and lower line by the segments.
The press-and-seal strip is cut out into multiple segments which are sewn or glued by super glue (N = 1, $ 2.6, re-usable) to the foam sheet (Figure 2). The aortic valve cusps are cut out of the condom in a semi-circular fashion, which is then held firmly by the plastic sealer. The semi-circle cusps need to be cut out with a diameter of 1.5 – 2 times larger than the distance between the commissures so when they are held by the press-and-seal segments can be easily trimmed to mimic a well-coapting valve. A strip of plain felt sheet (N = 1, $ 0.83, reusable) is attached around the lint roller tube as the sewing cuff (annulus) for implantation of a valved conduit or aortic valve.
Results/Functions
We were able to construct a multipurpose, anatomically realistic aortic root replacement simulator using the above materials both time and cost efficiently, using minimal surgical equipment. The simulator enables the residents to learn and practice procedures including; Coronary buttons re-implantation (Figure 2A), Aortic root replacement, Valve-sparing aortic root replacement (Figure 2B,C) and Stentless aortic valve replacement (Figure 2D). The foam sheet forms the core of the simulator, which allows the trainees to experience a perfectly simulated tissue handling and accurate angle of needle attack in complex aortic root and stentless valve surgery.