ASSESSING
THE PATENCY By
OF MICROVASCULAR LEO NIEUBORGH,
ANASTOMOSES
M.D.
Zuiderziekenhuis, Department of Surgery, Postbus 5994, 3008 BC Rotterdam, The Netherlands THE
usual technique for establishing patency of a small vessel anastomosis is that of Hayhurst and O’Brien (1975). A number 2 jeweller’s forceps grasps the vessel immediately distal to the anastomosis with sufIicient force to occlude it. A second forceps empties a short length of the “downstream” side of the vessel of blood. While the distal forceps still occludes the vessel the proximal forceps is removed; if the anastomosis is patent blood rushes in to fill the emptied segment. One deficiency of this test is that it is purely qualitative; the anastomosis is either patent or it is not. The test will not pick up a stenotic anastomosis as the following experiments have shown. The left femoral artery was divided in 25 female Wagrij rats about 30 weeks old. The artery was then repaired in the usual way using IO/O Ethilon sutures on a B.V.4 needle. All the rats survived and the anastomosis was examined from 6 to 14 weeks after the operation. Using the test described above, 23 of the 25 anastomoses were found to be patent. The abdominal aorta in all the rats was cannulated 2 mm distal to the origin
FIG. I. Subtraction arteriogram of a fully patent left femoral artery anastomosis. FIG. z. A stenotic left femoral artery anastomosis which passed the patency test of Hayhurst and O’Brien. Note the collateral vessels. FIG. 3. A completely occluded left femoral artery anastomosis. Here, too, collateral vessels have developed.
152
BRITISH
JOURNAL OF PLASTIC
SURGERY
of the renal arteries, Urografin was injected and X-rays taken. Subsequently the anastomosis was excised and examined histologically. Subtraction arteriograms showed that 4 of the 23 patent anastomoses were stenotic and the lumen was reduced to half its normal size. These stenotic anastomoses were found at the following intervals after operation: II weeks, 12 weeks and 14 weeks (2). Histological examination confirmed the stenosis; the partial obstruction was due to thrombus on the vessel wall. Figures I to 3 show typical arteriograms of fully patent, stenotic and completely occluded anastomoses. In all of the stenotic and occluded rats, collateral vessels had developed to bypass the obstruction. CONCLUSION When evaluating the patency of anastomoses of small blood vessels in experimental animals, it should be noted that the simple test of Hayhurst and O’Brien will not Such stenoses might well have a demonstrate partial obstruction at the suture line. deleterious effect on clinical replants and free flaps and their causation and avoidance should be further investigated. They can be demonstrated by arteriography and their occurrence confirmed histologically. REFERENCE HAYHURST? J. W. and O’BRIEN, B. McC. (1975). technique, patency rates and related factors.
An experimental study of microvascular British Journal of Plastic Surgery, 28, 128.
THE PATENCY By
OF MICROVASCULAR LEO NIEUBORGH,
ANASTOMOSES
M.D.
Zuiderziekenhuis, Department of Surgery, Postbus 5994, 3008 BC Rotterdam, The Netherlands THE
usual technique for establishing patency of a small vessel anastomosis is that of Hayhurst and O’Brien (1975). A number 2 jeweller’s forceps grasps the vessel immediately distal to the anastomosis with sufIicient force to occlude it. A second forceps empties a short length of the “downstream” side of the vessel of blood. While the distal forceps still occludes the vessel the proximal forceps is removed; if the anastomosis is patent blood rushes in to fill the emptied segment. One deficiency of this test is that it is purely qualitative; the anastomosis is either patent or it is not. The test will not pick up a stenotic anastomosis as the following experiments have shown. The left femoral artery was divided in 25 female Wagrij rats about 30 weeks old. The artery was then repaired in the usual way using IO/O Ethilon sutures on a B.V.4 needle. All the rats survived and the anastomosis was examined from 6 to 14 weeks after the operation. Using the test described above, 23 of the 25 anastomoses were found to be patent. The abdominal aorta in all the rats was cannulated 2 mm distal to the origin
FIG. I. Subtraction arteriogram of a fully patent left femoral artery anastomosis. FIG. z. A stenotic left femoral artery anastomosis which passed the patency test of Hayhurst and O’Brien. Note the collateral vessels. FIG. 3. A completely occluded left femoral artery anastomosis. Here, too, collateral vessels have developed.
152
BRITISH
JOURNAL OF PLASTIC
SURGERY
of the renal arteries, Urografin was injected and X-rays taken. Subsequently the anastomosis was excised and examined histologically. Subtraction arteriograms showed that 4 of the 23 patent anastomoses were stenotic and the lumen was reduced to half its normal size. These stenotic anastomoses were found at the following intervals after operation: II weeks, 12 weeks and 14 weeks (2). Histological examination confirmed the stenosis; the partial obstruction was due to thrombus on the vessel wall. Figures I to 3 show typical arteriograms of fully patent, stenotic and completely occluded anastomoses. In all of the stenotic and occluded rats, collateral vessels had developed to bypass the obstruction. CONCLUSION When evaluating the patency of anastomoses of small blood vessels in experimental animals, it should be noted that the simple test of Hayhurst and O’Brien will not Such stenoses might well have a demonstrate partial obstruction at the suture line. deleterious effect on clinical replants and free flaps and their causation and avoidance should be further investigated. They can be demonstrated by arteriography and their occurrence confirmed histologically. REFERENCE HAYHURST? J. W. and O’BRIEN, B. McC. (1975). technique, patency rates and related factors.
An experimental study of microvascular British Journal of Plastic Surgery, 28, 128.
