USE OF VEIN LOOPS IN RECONSTRUCTIVE PROCEDURES

PIETRO GIOVANOLI, M.D., and VIKTOR E. MEYER, M.D.*

The use of a temporary arteriovenous fistula prior to flapharvesting was suggested by Threlfall in 1982 (Threlfall, AustNZ J Surg 52:182–184, 1982). The basic idea is to use longvenous grafts that can be branched side-to-end to a mainartery at an easily accessible level using one of the well-established exposures from general vascular surgery. In re-constructive microsurgery, AV-loops are used in limb salvage

procedures and in cancer surgery. These patients have oftenundergone previous surgery and additional radiotherapy. AV-loops facilitate the use of normal recipient vessels out of thezone of injury, or far away from scar or irradiated tissue.

© 1998 Wiley-Liss, Inc.MICROSURGERY 18:242–245 1998

Predictable success in free tissue transfer and replantationsurgery requires an appropriate choice of recipient vessels.In complex cases, autologous vein grafts facilitate the use ofnormal recipient vessels out of the zone of injury, or faraway from scar or irradiated tissue. Especially when longvein grafts are required for extraanatomical connection offree tissue transfers the vein loop technique can be em-ployed, creating a temporary arteriovenous (AV) shunt. Wereport our own experience with the AV-loop technique anda review of the literature.

VEIN LOOP TECHNIQUE

In free microvascular tissue transfer, preparation of re-cipient vessels is often a tedious, difficult, and time-consuming part of the operation. For this purpose Threlfall1

recommended the use of a preliminary arteriovenous fistulaprior to flap harvesting. The basic idea was to use longautologous vein grafts that can be branched side-to-end to amain artery at an easily accessible level using one of thewell-established exposures from general vascular surgery.The technique is not limited to the lower limb. It can be usedin other parts of the body, including in head and neck, upperextremity (cephalic vein), and abdominal wall etc. Afterside-to-end anastomosis to the main artery it will function,temporarily, as an arteriovenous shunt, forming a loop(Figs. 1, 2). In a case where the ipsilateral greater or lessersaphenous vein is available, one of them can be used as apedicle vein graft. After this constantly perfused vein loopis optimally placed in the recipient area, the flap harvestedcan be brought into the defect. The vein loop is transected

between two vascular clamps at the most convenient level.Two separate vascular branches, one arterial and one ve-nous, result and the arteriovenous shunt is eliminated. Thesetwo vessels can now be easily anastomosed end-to-end tothe corresponding vessels of the flap. Due to the continuousperfusion of the vein graft until its final transection, tortu-osity, kinking, and spasm are avoided during manipulationsfor final positioning. The long vascular pedicle offers greatfreedom of optimal adjustment of the transferred tissue intothe recipient site.2,3

INDICATIONS

Limb Salvage Procedures

Microvascular reconstructions of the lower limb withcomposite defects are common after severe trauma of theleg. In patients with diabetes mellitus or severe peripheralvascular disease, on the other hand, limb salvage can beachieved with free microvascular tissue transfer. In cases oftrauma in the chronic phase, the posttrauma vascular se-quelae extend at least up to 10 cm beyond the visible limitsof skin involvement.3 The edema and inflammatory reactionin the zone of injury lead to fibrosis, vessel fragility, and therisk of arterial spasms. It is considered imperative to per-form anastomosis well away from the zone of trauma usinghealthy vessels.4 In these cases, extensive proximal dissec-tion of recipient vessels and, if necessary, interpositionalvein grafts or AV-loops, are recommended.

With the increase in limb salvage by arterial bypasssurgery and percutaneous catheter techniques, there aremore wound problems in the revascularized limbs to bedealt with.5 Free flaps compared with local flaps do not relyon local circulation. By performing microvascular anasto-moses at a level where good inflow can be obtained, eitherwith the bypass graft itself or, if needed, with arteriovenousloops or long interpositional vein grafts, these flaps becomea regional extension of the revascularization.6

Division of Hand, Plastic and Reconstructive Surgery, Department of Surgery,University Hospital Zurich, Zurich, Switzerland

*Correspondence to: Viktor E. Meyer, M.D., Head of the Division for Hand,Plastic and, Reconstructive Surgery, Department of Surgery, University Hos-pital Zurich, Ramistrasse 100, CH-8091 Zurich, Switzerland.

© 1998 Wiley-Liss, Inc.

Reconstructive Procedures in Cancer Surgery

Patients with extensive resections of malignant tumorsand primary reconstructions in extremitites and the trunk(especially in advanced breast cancer) are candidates forfree tissue transfers. Free flaps have also become an integralpart of the treatment of head and neck cancer patients. These

patients have often undergone previous surgery and addi-tional radiation therapy. Vein grafts have to be used when,under these circumstances, recipient vessels are not avail-able.7,8 Long vein loops derived from the cephalic vein maybe used in these difficult cases of trunk, arm, or head andneck free tissue transfers.9

Figure 1. A: Free saphenous vein graft from the contralateral side: side-to-end anastomosis to superficial femoral artery and greatersaphenous vein. B: Vigorous flow through the vein graft, acting now as a arteriovenous shunt. C: Loop-shaped arteriovenous shunt, nowbrought into the tissue defect over the proximal part of the tibia ready for transsection, and subsequent anastomosis to artery and vein of alatissimus dorsi free muscle flap. D: Vascular anastomoses performed in an easily accessible location. E: The flap is spread out over theanterior aspect of the tibia and will be covered by a skin graft.

Vein Loops in Reconstructive Procedures 243

DISCUSSION

Anastomoses that give rise to increased tension in thevessel have a poor prognosis. It is better in these cases to useautogenous vascular grafts. Interpositional vein grafts areused in complex cases where primary anastomoses betweenflap and available recipient vessels were limited due to pre-vious surgery or radiation. Long veins carry a higher risk ofthrombosis and flap failure.10,11 In these situations, the un-favorable circumstances seem to be more of a contributingfactor to vessel thrombosis and flap failure than any intrin-sic factor with the vein grafts themselves.7 In controlledexperimental models, interpositional vein grafts for arterialand venous repairs have the same patency rates as simplerepairs, and the same survival rates can be found in freeexperimental tissue transfers following revascularizationwith interpositional vein grafts compared to simple end-to-end anastomosis.12,13 The elective and planned use of veingrafts have been shown to be reliable and save.3,8,14 Ger-mann and Steinau15 reported success rates of 96.2% flapsurvival using a vein graft or a AV-loop in predominantly

trauma patients compared to 96.7% flap survival for a largeseries of flaps without vein grafts. The use of vein grafts canbe avoided by choosing the best reconstruction for an indi-vidual situation, e.g., long pedicled flaps should be favoredto minimize the use of vein grafts.16,17When vein grafts arerequired its use should be carefully planned, even in reex-ploration.3,15 The use of a temporary arterio-venous fistulaprior to flap harvesting was suggested by Threlfall in 1982.1

Threlfall advocated the two-stage procedure technique,transsecting the vein loop after a 7-day period of observa-tion. In our institution free tissue transfers using an AV-loopare single-stage procedures. This method allows a straight-forward extra-anatomical connection of free tissue transfers.This shortens the length of hospital stay and prevents therisk of temporary cardial failure by the AV-shunt volume ora possible steal effect of a large flap. For fear of high-flowthrombus forming at the arterial side of the vein graft,Acland proposed to perform anastomoses to the flap vesselsfirst before connecting the flap to the recipient artery.3 Thesubcutaneous extra-anatomical anastomoses are performedvery easy and contribute to facilitate postoperative moni-toring by simple palpation of the pulse in case of microvas-cular bone transfer. The use of vein loops in reconstructivemicrosurgery should be limited to complex cases whereirradiation, large tissue defects, or peripheral vascular dis-ease require normal recipient vessels out of the zone ofinjury, or far away from irradiated or scar tissue.

ACKNOWLEDGMENTS

We thank Claudia Meuli-Simmen, M.D., for her reviewof the manuscript.

REFERENCES

1. Threlfall GN: End to side microarterial anastomosis: A simplifiedtechnique.Aust NZ J Surg52:182–184, 1982.

2. Meyer VE, Largiade`r J: The ‘‘vein-loop-technique’’ for connection offree tissue transfers, in Brunelli G (ed):Textbook of Microsurgery.Milano, Masson, 1988, pp. 335–336.

3. Acland RD: Refinements in lower extremity free flap surgery.ClinPlast Surg17:733–744, 1990.

4. Devansh S: Prefabricated recipient vascular pedicle for free compos-ite-tissue transfer in the chronic stage of severe leg trauma.PlastReconstr Surg96:392–399, 1995.

5. Verga MP, D’Amore DF: Microvascular free tissue transfer after ar-terial revascularization in the elderly: An alternative to amputation.Ann Plast Surg21:348–353, 1988.

6. Atiyeh BS, Sfeir RE, Hussein MM, Husami T: Preliminary arteriove-nous fistula for free-flap reconstruction in the diabetic foot.PlastReconstr Surg95:1062–1069, 1995.

7. Schusterman MA, Miller MJ, Reece GP, Kroll SS, Marchi M, Goep-fert H: A single center’s experience with 308 free flaps for repair ofhead and neck cancer defects.Plast Reconstr Surg93:472–478, 1994.

8. Miller MJ, Schusterman MA, Reece GP, Kroll SS: Interposition veingrafting in head and neck reconstructive microsurgery.J ReconstrMicrosurg 9:245–251, 1993.

Figure 2. Arteriogram taken 2 weeks after latissimus dorsi muscletransfer to the lower leg, showing patent arterial part (vein graft) ofthe extraanatomical connection of the flap. (Reproduced from Meyerand Largiader 2 with permission of the publisher.)

244 Giovanoli and Meyer

9. Hallock GG: The cephalic vein in microsurgery.Microsurgery 14:482–486, 1993.

10. Khouri RK: Avoiding free flap failure.Clin Plast Surg19:773–781,1992.

11. Buncke HJ, Oliva A, Buncke GM, et al: Experience with over 1000microvascular transplantations: A retrospective review. Presented atthe 72nd Annual Meeting of the American Association of Plastic Sur-geons, Philadelphia, PA, May 9–12, 1993.

12. Zhang F, Oliva A, Kao SD, Newlin L, Buncke HJ: Microvascular veingrafts in the rat cutanous free-flap model.J Reconstr Microsurg10:229–233, 1994.

13. Zhang F, Oliva A, Kao SD, Newlin L, Buncke HJ: Microvascular

vein-graft patency in the rat model.J Reconstr Microsurg10:222–227,1994.

14. Grotting JC: Prevention of complications and correction of postopera-tive problems in microsurgery of the lower extremity.Clin Plast Surg18:485–489, 1991.

15. Germann G, Steinau HU: The clinical reliability of vein grafts infree-flap transfer.J Reconstr Microsurg12:11–17, 1996.

16. Kroll SS, Schusterman MA, Reece GP, Miller MJ, Evans GRD, RobbGL, Baldwin BJ: Choice of flap and incidence of free flap success.Plast Reconstr Surg98:459–463, 1996.

17. Suominen S, Asko-Seljavaara S: Free flaps failure.Microsurgery16:396–399, 1995.

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