Ann Thorac Surg 2000;69:1282-1284
© 2000 The Society of Thoracic Surgeons
HOW TO DO IT
"Cobrahead" graft for intercostal artery implantation during descending aortic replacement
John A. Elefteriades, MDa,
Michael A. Coady, MDa,
Dimitri J. Nikas, MDa,
Gary S. Kopf, MDa,
Richard J. Gusberg, MDb
a Section of Cardiothoracic Surgery, Yale University School of Medicine, New Haven, Connecticut, USA
b Section of Vascular Surgery, Yale University School of Medicine, New Haven, Connecticut, USA
Address reprint requests to Dr Elefteriades, Section of Cardiothoracic Surgery, Yale University School of Medicine, 121 FMB, 333 Cedar St, New Haven, CT 06510
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Abstract
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A technique for a separate sidearm graft ("cobrahead") to facilitate reattachment of intercostal arteries in descending aortic replacement is described. The technique allows for very prompt restoration of spinal cord blood flow (via a Y attachment from the arterial perfusion circuit). The technique permits a simple, quick, and fully accessible anastomosis, technically more facile than the traditional side-to-side anastomosis. None of 7 patients treated with this technique had early or late paraplegia. Preliminary computed tomographic follow-up scans confirm patency of the cobrahead graft.
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Introduction
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Despite decades of concerted laboratory and clinical investigation, paraplegia after descending aortic replacement remains an extremely serious problem plaguing the thoracic aortic surgeon [1, 2]. Many authors currently recommend reimplantation of multiple intercostal arteries, either on the basis of preoperative angiographic identification of arteries perfusing the lower spinal cord or on the basis of the anatomic probability that such an artery arises from the T8-L2 level, usually on the left side.
In many cases, resection of the thoracic aorta can be made to stop short of the intercostal arteries in question. In other cases, a sharply beveled anastomosis may replace a long segment of anterior aorta while preserving the posteriorly located intercostal arteries. When the T8-L2 region needs to be spanned completely by aortic replacement, formal implantation of intercostal arteries is carried out, usually by side-by-side graft-to-aorta anastomosis (inclusion technique). The inclusion technique for intercostal artery anastomosis is an excellent method, with years of experience behind it. By virtue of brisk aortic flow, the intercostal arteries are constantly "washed" by rapidly moving blood, creating a very favorable circumstance for continued patency.
However, the intercostal side-by-side anastomosis may be technically troublesome. Tightening the suture line optimally, essential because of later incomplete accessibility, may be difficult to accomplish without tearing friable aortic tissues. Bleeding from this site is not infrequent. Bleeding that requires reclamping of the aorta or graft (with attendant increase of cross-clamp time) may make the construction of this anastomosis a net negative intervention vis-à-vis spinal cord preservation. Retraction of the graft at the side-to-side anastomosis may easily disrupt the delicate tissue, leading to troublesome bleeding. For these reasons, alternate techniques may merit consideration.
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Technique
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We have utilized a "cobrahead" technique for intercostal artery implantation. We spatulate a separate 10 to 12 mm collagen-impregnated graft and anastomose this graft end-to-side to the intercostal zone of the aorta to be reanastomosed (Fig 1). In our experience, this anastomosis is straightforward technically, with good exposure even after completion. This graft is done initially, before any other anastomosis. In this way, the spinal cord is reperfused within the 10 to 12 minutes that it takes to create this intercostal anastomosis. (Our standard perfusion for isolated descending aortic operations is left-atrial-to-femoral artery perfusion through a centrifugal pump.) Once the main aortic graft is completed, proximal and distal, the cobrahead graft is anastomosed quickly to the side of the main graft, with a short additional period of ischemia, reestablishing permanent intercostal artery connection. We prefer a long, gentle curve for the cobrahead graft, bringing it behind the main aortic graft and permitting anastomosis to the front surface of the main graft.
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Fig 1. Cobrahead accessory graft for intercostal artery reimplantation. Insets show spatulation of the graft (left) and depiction of connection to arterial perfusion circuit that allows prompt restoration of spinal cord blood flow (right).
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We have utilized the cobrahead technique in 7 patients over the last 2 years. None developed paraplegia at any point in early or late follow-up. We also utilized both the bevel technique and the side-to-side anastomosis during the same time period in individual patients.
Figure 2 shows a postoperative computed tomographic scan of a patent cobrahead graft in a 51-year-old woman with intact neurologic function after one-stage replacement of the entire descending and abdominal aorta and iliac arteries. The cobrahead graft must represent the only direct intercostal or lumbar source of blood flow to the low spinal cord in this patient.
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Fig 2. Postoperative computed tomographic scan of patent accessory cobrahead graft in a 51-year-old woman with intact neurologic function after one-stage total replacement of the descending and abdominal aorta and iliac arteries. Arrow indicates accessory graft coming out from main aortic graft.
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Figure 3 shows a patent cobrahead graft in a 63-year-old man who underwent total aortic replacement (in two stages) from just above the coronary arteries to the aortic bifurcation. Again, the cobrahead graft represents the only direct aortic supply to the lower spinal cord in this patient.
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Fig 3. Postoperative computed tomographic scan of patent accessory cobrahead graft in a 63-year-old man with total aortic replacement from the coronary ostea to the aortic bifurcation. (A) Cobrahead graft running parallel to main aortic graft in transverse section. (B) Three-dimensional reconstruction. The arrow shows the accessory graft in both (A) and (B).
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Comment
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We present the cobrahead technique as another technical option for intercostal artery reattachment in descending aortic operations. Potential advantages of the cobrahead technique may be multiple: - The intercostal anastomosis is technically simple and fully accessible without undue retraction of the main aortic graft.
- Early reperfusion of the intercostal arteries is accomplished (even before the proximal aortic anastomosis is completed). Spinal cord ischemia is minimized by early perfusion of the cobrahead graft through a sidearm from the arterial perfusion circuit. (However, the number of patients in this series is insufficient to draw inferences regarding the impact of this technique on the general incidence of paraplegia.)
- Early intercostal anastomosis decreases the ambient blood in the aortic operative field so that less blood needs to be recycled through the cell-saving apparatus.
Our experience with this technique is limited, and although we present this option for inclusion in the aortic surgeon’s armamentarium, caution in its application is recommended. We are pleased to note that other centers have found the sidearm technique useful [3]. However, it is unknown whether patency will equal that of the traditional side-by-side anastomosis. Our early radiographic assessment is encouraging, as is the freedom from early or late paraplegia. The cobrahead technique is analogous to the Cabrol technique for coronary artery reimplantation in ascending aortic replacement, which has been widely validated (albeit with isolated reports of thrombosis) [4]. Of course, the vascular runoff of the coronary arteries may exceed that of the intercostal arteries.
We routinely utilize preoperative spinal angiography to identify vital intercostal arteries, and their revascularization by the cobrahead technique has, in this small experience, proved adequate to preserve spinal cord function.
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References
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Svennson L.G., Crawford E.S., Hess K.R., Coselli J.S., Safi H.J. Variables predictive of outcome in 832 patients undergoing repairs of the descending thoracic aorta. Chest 1993;104:1248-1253.[Free Full Text]
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Kouchoukos N.T., Wareing T.H., Izumoto H., Klausing W., Abboud N. Elective hypothermic cardiopulmonary bypass and circulatory arrest for spinal cord protection during operations on the thoracoabdominal aorta. J Thorac Cardiovasc Surg 1990;99:659-664.[Abstract]
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Jacobs M.J.H.M., Meylaerts S.A., de Haan P., de Mol B.A., Kalkman C.J. Strategies to prevent neurologic deficit based on motor-evoked potentials in type I and II thoracoabdominal aortic aneurysm repair. J Vasc Surg 1999;29:48-59.[Medline]
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Cabrol C., Gansjbankhch I., Pavie A. Surgical treatment of aneurysms of ascending pathology. J Card Surg 1988;3:167-180.[Medline]
Accepted for publication December 3, 1999.
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Invited commentary
- Marc A.A.M. Schepens
Ann. Thorac. Surg. 2000 69: 1284.
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Abstract
Introduction
