NEW IDEAS – ADULT CARDIAC
Interactive CardioVascular and Thoracic Surgery 20 (2015) 1–6 doi:10.1093/icvts/ivu302 Advance Access publication 17 September 2014
Sameh M. Said* Division of Cardiovascular Surgery, Mayo Clinic, Rochester, USA * Corresponding author. 200 First Street SW, Rochester, MN 55905, USA. Tel: +1-507-2029170; fax: +1-507-2557378; e-mail:
[email protected] (S.M. Said). Received 27 February 2014; received in revised form 10 June 2014; accepted 13 July 2014
Abstract OBJECTIVES: Simulation has become an integral part of thoracic surgical training that has been proven to improve residents’ skills. The purpose of the current study was to develop a low-fidelity and low-cost simulator for aortic root surgery that could provide training in multiple aortic valve and root procedures. METHODS: The current aortic root simulator is made of inexpensive, easily available materials and can be built easily to simulate an aortic root. The basic components are rubber glove, plastic cup, silk tape and small silastic tubes. RESULTS: The simulator was proven to be simple and cost-effective. Several procedures have been performed with this simulator such as standard aortic valve replacement, aortic valve repair, valve-sparing aortic root replacement, and modified Bentall procedure. The building of the simulator is in itself a beneficial process to the resident. The benefit of its construction is a great learning experience. The simulator was placed in a box to create a portable device that can be used by the resident anywhere. CONCLUSIONS: This is a simple and cost-effective aortic root simulator that can be built by the thoracic surgical resident to provide training in multiple aortic valve and aortic root procedures. Such low-fidelity portable simulators are beneficial to young trainees and may contribute to improvement of technical skills and procedural knowledge that ultimately leads to improved performance in the operative field. Keywords: Aortic root • Simulation • Resident training • Aortic valve replacement
INTRODUCTION
METHODS
Surgical simulation is not new and in the past, surgeons used to practise procedures on animals and/or cadavers [1]. Recently, simulators have become an integral part of any good surgical residency programme. They have been proven to improve trainees’ surgical skills and reinforce important surgical concepts [2]. Most simulators currently are done using animal heart models [3], which may be expensive or not available easily for trainees. Low-fidelity simulators in particular help minimize the cost of animal or cadaveric training and add the potential of being portable, easy to be built, and used anywhere by the surgical trainee. Verberkmoes and Verberkmoes-Broeders [4] presented a lowfidelity mitral valve simulator that can be used for training in nearly the full range of both mitral and tricuspid valve surgical techniques and can be used for both open and minimally invasive approaches. In this paper, we present another low-fidelity simulator for aortic valve and root procedures. This is an easy-to-build, portable and low-cost simulator that can further help thoracic surgical residents and young trainees in their endeavour.
The basic components of the simulator include the following (Fig. 1). (i) A silk tape, which is used to simulate the aortic wall. The advantage of using a silk tape as a material is its ability to be cut in a similar fashion to the aortic wall and the ease of sewing to the prosthetic grafts that will be used to replace the aortic wall or root. (ii) A plastic cup, which will be cut in a fashion to simulate the posts and the annulus of the aortic valve (Fig. 2A and B). The silk tape will be wrapped around the plastic cup that helps in maintaining the shape of a free-standing aortic root (Fig. 2C and D). (iii) A pair of silastic tubes that will simulate coronary arteries and these can be sewn to the silk tape in the location of the coronary arteries at both the left and right coronary sinuses of Valsalva (Fig. 3). (iv) A piece of latex glove that will be cut and sewn to simulate the leaflets of the aortic valve. The following represents the steps used to build up the aortic root simulator. (i) The plastic cup is cut in a fashion to simulate the three aortic posts/commissures and the annulus (Fig. 2A and B). The size of that cup can be changed easily to simulate different aortic annular sizes. (ii) The silk tape is wrapped around the plastic cup to form the aortic wall and determine the annulus location (Fig. 2C and D). (iii) A marker will be used to mark the location of the annulus, commissures and the sinuses of Valsalva (Fig. 2E). (iv) A piece of the latex glove is cut as a strip and is sewn to the three
† Presented at the 27th Annual Meeting of the European Association for CardioThoracic Surgery, Vienna, Austria, 5–9 October 2013.
© The Author 2014. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.
NEW IDEAS
My aortic root simulator: if I can build it, you can build it†
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S.M. Said / Interactive CardioVascular and Thoracic Surgery
Figure 1: The basic components and the basic instruments needed to build a low-fidelity aortic root simulator.
posts of the plastic cup to simulate the aortic valve leaflets above the level of the annulus (Fig. 4A–D). The aortic valve can be built to be a bicuspid valve as well in the same manner. (v) Two holes are then created in the silk tape at the presumed location of the left and right coronary arteries, and a small piece of silastic tube is cut and is sewn to each of these holes to represent the left and right coronary arteries. This is usually done using a running 3/0- or 4/0-polypropylene suture. Now, the resident will have a free-standing aortic root model with aortic valve leaflets and two coronary arteries that can be used to perform several aortic valves and root procedures (Fig. 5). The silk tape also can be used to fix the aortic root model to a working board to maintain its position as a standing root to facilitate suturing. Another alternative is to sew the model in the board with heavy suture to facilitate its use as a free-standing model. Even if there is limited supply of prosthetic valves or grafts, the resident still is able to build a bioprosthesis (Fig. 6A), graft (Fig. 6B) or a valved conduit (Fig. 6C) from the same materials as
Figure 2: (A) The plastic cup is cut in a way to simulate (B) the aortic annulus and the posts of the aortic root. Using a plastic cup for this is beneficial as it is stiff enough to hold the aortic root model; (C) the silk tape is wrapped around the plastic cup to form the aortic wall. Using the silk tape is helpful as surgical needles can pass through that easily, and almost similar to a prosthetic graft material (D), a marker is used to determine the location of the annulus and the future coronary arteries within the sinuses of Valsalva (E).
mentioned previously and use them as substrates to perform any aortic valve and/or root procedures.
RESULTS The previously described simulator was used to perform the following aortic valve and root procedures: (i) aortic valve repair
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and/or replacement by either biological or mechanical valves (Fig. 7A); (ii) aortic valve replacement and supracoronary ascending aorta replacement (Fig. 7B); (iii) aortic root replacement applying either the modified Bentall or Bio-Bentall technique; and (iv) valve-sparing root replacement and aortic root remodelling technique (Fig. 7C). It is beneficial for the trainee to build the simulator him/herself as it is an anatomical learning experience in itself and the trainee will become familiar with the aortic root anatomy this way. Training in sewing coronary arteries is also part of building this root. During the procedure, the trainee will be able to simulate the exact operative steps of aortic valve and/or root replacement including excision of the valve leaflet, sizing the annulus and reimplanting the coronary arteries if needed to.
COMMENT
Figure 3: Creating the coronary ostia in the silk tape and sewing a pair of silastic tubes at the presumed location of the coronary arteries.
Residents and trainees are faced currently with several challenges during their training such as duty hour regulations, the expansion of minimally invasive practice, robotic techniques, and percutaneous interventions [5]. These challenges no doubt affect the quality of training. Simulations have emerged recently as an alternate way of improving surgical training and increasing learning opportunities for residents through a less-expensive and practical way compared with cadaver or animal use. There is also a simulation curriculum in progress for thoracic surgery with specified modules and assessment tools; this curriculum is developed by the Joint Council for Thoracic Surgery Education [6]. Establishment of the Boot Camp by the Thoracic Surgery Directors Association in 2008 was an important example of the advancement in the field of simulation and thoracic surgical training [7].
Figure 4: (A–D) Constructing the final steps in the aortic root model by cutting a piece of the latex glove and suture it in place to form the aortic valve leaflets. At that stage, the trainee can build a tricuspid or bicuspid aortic valve.
NEW IDEAS
S.M. Said / Interactive CardioVascular and Thoracic Surgery
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S.M. Said / Interactive CardioVascular and Thoracic Surgery
Figure 5: The completed aortic root model showing the aortic valve leaflets and the attached coronary ostia.
There are three main types of surgical simulation: the performance simulator, the virtual reality simulator, and the bench model [8]. The human performance simulator is a high-technology simulator that can be used for an entire team training as well. It simulates the operating theatre environment and can include patient variation with the ability for feedback. The virtual simulator is computer-based usually with no physical component. It is reusable and can be customized to interact with the user and provide assessment and feedback. This technology may be best suited for thoracoscopic training. The final technique, the bench model, is the simplest and most cost-effective method of training. These models are available and can be built by the trainee easily to simulate a component of the operation and can be used as a step in training before the real challenge comes in the operating theatre. Low-fidelity simulators are perfect example of the simple bench model of simulation. These simulators are built from readily available and inexpensive materials and have the advantage of being portable, which facilitates its use anywhere by the trainee (Fig. 8A and B). The current aortic root model is an example of such lowfidelity simulators, which can be used to perform a wide range of aortic valve and root procedures. The trainee will be able to size the aortic annulus, cut the leaflets of the aortic valve, perform leaflet repair if needed, and reimplant the coronary arteries for a root replacement technique.
Figure 6: The same simple materials used for constructing the aortic root can be used to build (A) a bioprosthesis, (B) prosthetic graft and (C) a valved conduit to be used with the model.
Figure 7: The aortic root model can be used to perform several aortic valve and root procedures, (A) aortic valve replacement with a mechanical prosthesis, (B) supracoronary ascending aorta replacement, and (C) valve-sparing aortic root replacement using the remodelling technique.
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NEW IDEAS
S.M. Said / Interactive CardioVascular and Thoracic Surgery
Figure 8: A major advantage of this low-fidelity simulator is the simplicity and portability. (A) A plastic box will be carried by the resident anywhere to be able to practise, and an opening is created in the cover of the box where the aortic root model is mounted to create depth perception, which is important during practice, (B) all instruments and materials needed will be carried inside the same box.
to build their own simulators. This way they will be ready to face the real challenges in the operating theatre when the time comes videos 1 and 2. Conflict of interest: none declared.
REFERENCES
Video 1: Formation of aortic valve leaflets using a piece of rubber glove and 4/0-prolene suture. Each strip of rubber is sutured to each post either at one or two spots to form the leaflets and in the same way, the valve can be constructed as bicuspid or normal tricuspid.
[1] Anastakis DJ, Regehr G, Reznick RK, Cusimano M, Murnaghan J, Brown M et al. Assessment of technical skills transfer from the bench training model to the human model. Am J Surg 1999;177:167–70. [2] Al-Kadi AS, Donnon T, Oddone Paolucci E, Mitchell P, Debru E, Church N. The effect of simulation in improving students’ performance in laparoscopic surgery: a meta-analysis. Surg Endosc 2012;26:3215–24. [3] Joyce DL, Dhillon TS, Caffarelli AD, Joyce DD, Tsirigotis DN, Burdon TA et al. Simulation and skills training in mitral valve surgery. J Thorac Cardiovasc Surg 2011;141:107–12. [4] Verberkmoes NJ, Verberkmoes-Broeders EM. A novel low-fidelity simulator for both mitral valve and tricuspid valve surgery: the surgical skills trainer for classic open and minimally invasive techniques. Interact CardioVasc Thorac Surg 2013;16:97–101. [5] Carter BN. The fruition of Halsted’s concept of surgical training. Surgery 1952;32:518–27. [6] Verrier ED. Joint Council on Thoracic Surgical Education: an investment in our future. J Thorac Cardiovasc Surg 2011;141:318–21. [7] Hicks GL Jr, Brown JW, Calhoon JH, Merrill WH. You never know unless you try. J Thorac Cardiovasc Surg 2008;136:814–5. [8] Trehan K, Kemp CD, Yang SC. Simulation in cardiothoracic surgical training: Where do we stand? J Thorac Cardiovasc Surg 2014;147:18–24.
eComment. How trainees perform and develop their skills on the simulator
Video 2: Using 4/0-prolene suture facilitates suturing through the rubber glove and the silk tape. This video shows the completed valve leaflets.
This simple tool has the potential to provide thoracic residents with an easy-to-build, cost-effective simulator to perform a wide range of aortic valve and root procedures. This will contribute to their surgical skills and operative knowledge needed in the operating theatre. Finally, we should encourage the younger trainees or even medical students who have an interest in cardiothoracic surgery
Authors: Meletios A. Kanakis, Constantinos Loukas, Evangelos Georgiou and Achilleas Lioulias Department of Thoracic Surgery, Sismanoglio General Hospital of Athens, Athens, Greece doi: 10.1093/icvts/ivu379 © The Author 2014. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved. We have read with great interest this article based on a fascinating idea [1]. The author describes the development of a bench-type simulator for aortic root surgery using some inexpensive and easily available materials. Despite significant progress in the development of training systems for general surgical procedures, the variety of
