AUTOGENOUS MICRO-ARTERIAL GRAFTS FEMORAL VEIN IN RABBITS

TO THE

By B. McC. O’BRIEN,B.Sc., M.D., M.S., F.R.C.S., F.R.A.C.S., F.A.C.S., T. K~JBO,M.D. and G. N. THRELFALL,F.R.A.C.S. Microsurgery Research Unit, St Vincent’s Hospital, Melbourne, Australia

IN clinical microvascular surgery it is sometimes convenient to use a small segment of a dispensable artery as a graft for the reconstruction of an important vein. This situation may arise when a divided artery lies within the operative field, whereas to obtain a suitable donor vein would require further surgery at another site. The handling of a small segment of artery is technically easier than a similarly sized segment of vein. This report examines the repair of femoral vein defects in rabbits with autogenous arterial grafts taken from the femoral artery of the opposite side. TECHNIQUES All operations were performed on white rabbits weighing between 1.5 kg and 2.5 kg. They were anaesthetised with intravenous Nembutal (30 mg/kg) supplemented with Halothane, nitrous oxide and oxygen by mask. Using standard micro techniques and micro instruments, the left femoral artery was isolated through a longitudinal groin incision, The arteries ranged from 0.8 mm to I ‘3 mm in diameter. Small branches of the artery were coagulated and divided. A segment of artery measuring 15 mm in length prior to sectioning was removed between ligatures. The graft was stored in normal or heparinised normal saline. The right femoral vein was then isolated through a longitudinal groin incision. The diameters ranged from 1.0 mm to 1.3 mm, the vein usually being slightly larger than its companion artery. A double microvascular clamp was used to isolate a length of vein from which a 5 mm segment was measured and then removed. The arterial grafts were sutured into the vein defects using Ethicon IO,‘Omonofilament Nylon on a BV2 needle. Ten to twelve interrupted sutures were inserted at each anastomosis. On completion of the anastomosis the proximal clamp was removed followed immediately by the distal clamp. The grafts were divided into 3 groups according to the type of irrigating fluid used during the operation : Group I (15 grafts) irrigated with heparinised saline, IOOO IU heparinroo ml normal saline. Group II (15 grafts) irrigated with normal saline. Group III (IO grafts) irrigated with magnesium sulphate solution as described by Acland (1972). The magnesium sulphate solution was used as a topical irrigation during the surgery and dripped on the anastomosis for a further 20 minutes after its completion. Address for reprints : B. McC. O’Brien, Director, Microsurgery Melbourne, Victoria 3065, Australia. 32/3--c

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Research Unit, St Vincent’s Hospital,

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BRITISH

JOURNAL

OF PLASTIC

SURGERY

All anastomoses were inspected after 30 minutes and found to be patent. The wounds were then closed. Late patency was assessed by exploration at intervals ranging from 7 to 14 days postoperatively, the period which indicates the truest patency rate (Hayhurst and O’Brien, 1975). RESULTS

Forty autogenous artery to vein grafts were performed, a 15 mm graft filling a 5 mm defect in vessels approximately I-O mm in diameter. An immediate patency rate of 100 per cent was achieved in all groups. The patency rate as assessed by exploration at 7 to 14 days remained IOO per cent for the Group I grafts. Two grafts were occluded by thrombus in Group II and one graft was thrombosed in Group III (Table). TABLE

Patency rates of micro-arterial

grafts to the femoral vein of the rabbit

Number Group I Group II Group III

of vessels 15 15 IO

Result looyo

87% 90%

DISCUSSION

With the advent of replantation surgery and microvascular free transfer of composite tissues, interest developed in the surgical reconstitution of small veins. Buncke and Murray (1971) demonstrated the use of autogenous arterial grafts in the reconstitution This report established that arterial of arteries of approximately I mm in diameter. autografts can also be used to fill defects in small veins with reliable results. There would appear to be no advantage apart from convenience in using arterial autografts (as opposed to venous autografts) to fill defects in small veins. The procedure has been of clinical value in digital replantation where an unrepaired artery has been used as graft material for repair of a dorsal vein. This reduces the need to seek graft material elsewhere and the easier handling of the small piece of artery expedites the procedure. The use of grafts in the vessels may allow the need for bone shortening to On be modified in those cases in which it is particularly undesirable or impossible. other occasions there may be vessel deficiency, even with bone shortening, especially in avulsion injuries. Factors in the technique which led to satisfactory patency results were the use of a graft of adequate length without excessive tension and the meticulous placement of the An arterial graft measuring 15 mm in length prior to sectioning shrinks sutures. markedly when removed but not nearly as much as a similar length of vein. Similarly, a 5 mm defect in the vein will expand markedly when the divided ends are free to retract. All small vessels, particularly veins, are prone to narrowing of the lumen if anastomosed under tension. Meticulous suture placement keeps the number of sutures to a minimum. The choice of irrigating fluid did not appear to be significant in the small number of cases reported. SUMMARY Forty autogenous arterial grafts 15 mm in length filled 5 mm defects in the femoral veins of rabbits approximately I-O mm in diameter. Patency rates of 87 to I00 per cent were achieved at 7 to 14 days.

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This work is supported b-v a grant from the National Health and Medical Research Council of Australia. REFERENCES ACLAND, R. D. (1972). Prevention of thrombosis in microvascular surgery by the use of magnesium sulphate. British Journal of Plastic Surgery, 25, 292. BUNCKE, H. J. and MURRAY, D. E. (1971). Autogenous arterial interposition grafts of less than I mm in external diameter in rats. “Transactions of the 5th International Congress

of Plastic Surgery”, edited by Hueston, J. Melbourne : Butterworths. (1975). Experimental study of microvascular technique, patency rates and related factors. British Journd of Plastic Surgery, 28, 128.

HAYHURST?J. W. and O’BRIEN, B. McC.

Autogenous micro-arterial grafts to the femoral vein in rabbits.

AUTOGENOUS MICRO-ARTERIAL GRAFTS FEMORAL VEIN IN RABBITS TO THE By B. McC. O’BRIEN,B.Sc., M.D., M.S., F.R.C.S., F.R.A.C.S., F.A.C.S., T. K~JBO,M.D...
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