Ann Thorac Surg 1999;68:2389
© 1999 The Society of Thoracic Surgeons
Correspondence
Virtual reality imaging of chest wall and the heart
Eugene K.W. Sim, FRCSa,
Quek Swee Tian, FRCRa,
Lenny Tan Kheng Ann, FRCRa,
Reida M. El Oakley, FRCSa
a Division of Cardiothoracic Surgery, National University Hospital, 5 Lower Kent Ridge Rd, Singapore 119074
e-mail: sursimkw{at}nus.edu.sg
To the Editor
We read with interest the article by Reardon and colleagues [1] entitled "The Anatomical Aspects of Minimally Invasive Cardiac Valve Operations." With the current enthusiasm in the minimally invasive approach to valvular heart operation, detailed evaluation of the relationship of cardiac valves to the chest wall has become an essential prerequisite for the success of this new approach. In their article, Reardon and associates examine the relationship of the cardiac valve anatomical position in relation to the surface anatomy of the chest in cadavers. However, the authors did not state the number of cadavers dissected, nor did they discuss whether there were any variations in the position of structures in different subjects. Furthermore, the anatomical relation of the chest wall surface in an arrested heart, collapsed lungs, and exsanguinated circulatory system, may not be similar to that in a living human subject.
For patients undergoing minimally invasive valve operation we have used Ultrafast Computer Tomography (Imatron Inc, South San Francisco, CA), with contrast to obtain three dimensional reconstructions of the ribcage and cardiac structures. These were initially done separately, and subsequently merged into one scan.
We identified the position of the aortic, mitral, and tricuspid valves, and calculated their distances from a fix reference point on the chest wall. The preliminary findings show that there is considerable variation in the position of the cardiac structures in relation to the rib cage between patients. For example, the distance of the aortic valve to the manubrium sternal junction varied from 1.7 to 8 cm (mean 4.0 ± 1.2 cm). These findings suggest that one particular incision may not be suitable for all patients. To circumvent this difficulty, we have simulated the operative exposure by excluding the relevant segment of the chest wall, eg, the lower partial sternotomy or J incision was simulated by excluding the lower third of the sternum and the adjacent costal cartilages (Fig 1). This radiographic technique may be a useful tool in preoperative planning of the ideal minimally invasive approach to the valvular heart operation.
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Fig 1. Three dimensional reconstruction of ultrafast computed tomographic images of the heart and chest wall. The right hemisternum and costosternal junctions have been excluded to show the underlying structures. (SCV = superior vena cava; RA = right atrium; AO = aorta; RV = right ventricle.)
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References
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Reardon M.J., Conklin L.D., Philo R., Letsou G.V., Safi H.J., Espada R. The anatomical aspects of minimally invasive cardiac valve operations. Ann Thorac Surg 1999;67:266-268.[Abstract/Free Full Text]
