British _%umal of PlasticSurgery (1977), 30, 54-58
THE SLIDING TRANSPOSITION FLAP: ITS APPLICATION TO LEG DEFECTS By S. H. HARRISON,F.R.C.S., L.D.S., R.C.S.E. and M. N. SAAD,F.R.C.S., F.R.C.S.(Ed.) The Plastic Surgey
Unit, Wexham Park Hospital, Slough, Beds
IT is a well known fact that local skin flaps do well in the region of the knee, ankle and sole of the foot. In the leg, however, their survival is less certain, and to quote Cormely (1968): “Local pedicle flaps with only a single pedicle should not be used in the leg because of limited collateral circulation. Such flaps require one delay or more, a factor that greatly diminishes their usefuhiess”. Whilst this limited collateral circulation in the leg may be partly to blame, there is another factor which influences the fate of these flaps, particularly in the lower third of
0 1
02 FIG. I.
The bipedicle or strap flap. The pedicles are subjected to transverse tension, thus depriving the central part of adequate blood supply. FIG. 2. The sliding transposition
54
flap.
THE
SLIDING
TRANSPOSITION
FLAP
BRITISH
FIG. 4.
FIG. 5.
JOURNAL
OF PLASTIC
SURGERY
Two proximally based flaps used to resurface larger defects.
Excision of an unstable
scar and resurfacing
with z sliding transposition
flaps.
THE
SLIDING
TRANSPOSITION
FLAP
57
the leg. This is the lateral movement of the flap across the convex surface, resuhing in transverse tension with further embarrassment to the blood supply. This tension is often the final insult to a flap already deprived of most of its nutrition, and it may be the cause of necrosis. The bi-pedicle, or “strap” flap (Fig. I) perhaps and undeservedly the most widely used flap in the leg, is similarly at risk. The lateral excursion of this flap on a convex surface subjects the two pedicles to transverse tension. The central part is thus deprived of adequate blood supply, and necrosis then occurs at the very site where good viable tissue is most needed. A safer version of the “strap” flap was described by Crawford in 1957, but this requires two stages. It is interesting to note that whereas local flaps in the leg are affected by this transverse tension, cross leg flaps are safe when inset comfortably on the opposite leg. However, should a cross leg flap be delayed and resutured into its original site, the resultant oedema may cause additional tension leading subsequently to necrosis of part of the flap. Maisels pointed out in 1967 that, should a cross leg flap be delayed, it should be resutured in its retracted position, and the remaining defect covered by a split skin graft. The effect of tension on the survival of skin flaps was proved experimentally by Patterson in pigs in 1971. In this paper we describe a local flap of such design that this transverse tension is obviated by insetting the distal oblique edge of the flap into the contra-lateral side of the
58
BRITISH JOURNALOF PLASTIC SURGERY
defect (Fig. 2), thus sliding the long axis of the flap transversely around the convexity of the limb. TECHNIQUB A healthy and unscarred area of skin i.s selected medial or lateral to the defect (Fig. 3, A). The flap is planned so that its distal oblique edge is as long as the contralateral side of the defect. After raising the flap down to deep fascia (Fig. 3, B) the recipient site is prepared and the flap inset (Fig. 3, c). The flap donor site is then grafted. A fairly obvious dog’s ear can be expected to appear at the base of the flap, but the temptation to trim it should be resisted. It usually readjusts spontaneously, and none of our cases required subsequent trimming. For larger defects two such flaps can be used (Fig. 4). Both flaps are based proximally with their bases on different levels on the limb (Fig. 5). MATERIAL Since Ig6g 13 patients were successfully treated with sliding transposition flaps to repair small to medium-sized defects in the leg. These flaps have also been used in the knee and ankle regions, but these sites are usually favourable for conventional local flaps, and have therefore been excluded from this series. Ages ranged from 18 to 61 with an average of 38. None of the flaps required delay, except I case in which the only flap donor site available was on an old cross leg flap (Fig. 6). Approximately half the cases had defects in the middle third of the leg; the remainder shared equally between the upper and lower thirds. All our flaps survived. Primary healing was achieved in all but I case. In this instance bone infection persisted, a sinus formed, and this required a further procedure, including excision of the infected bone, saucerisation, and skin grafting. CONCLUSION Although local skin flaps are not particularly favourable in the leg, avoidance of transverse tension makes it possible to use local flaps to resurface small to medium-sized defects in I stage. We are grateful to Miss K. Ockendon for the diagrams and to Mr D. Gr@n for the photographs.
REFERENCES CONNELY, J. R. (1968). Reconstructive procedures of the lower extremity, in “Plastic Surgery”, edited by W. C. Grabb and J. W. Smith, p. 784. Boston: Little, Brown & Company. CRAWFORD,B. S. (1957). The repair of defects of the lower limbs using a local flap. British Journal of Plastic Surgery, IO, 32. PATTERSON, T. 1. S. (1971). The effects of tension on the survival of skin flaps. “Transactions of the 5th International Congress of Plastic and Reconstructive Surgery”, p. 807. Australia: Butterworth. SAAD,M. N. (1970). The problems of traumatic skin loss of the lower limbs, especially when associated with skeletal injury. British Journal of Surgery, 57, 604.
THE SLIDING TRANSPOSITION FLAP: ITS APPLICATION TO LEG DEFECTS By S. H. HARRISON,F.R.C.S., L.D.S., R.C.S.E. and M. N. SAAD,F.R.C.S., F.R.C.S.(Ed.) The Plastic Surgey
Unit, Wexham Park Hospital, Slough, Beds
IT is a well known fact that local skin flaps do well in the region of the knee, ankle and sole of the foot. In the leg, however, their survival is less certain, and to quote Cormely (1968): “Local pedicle flaps with only a single pedicle should not be used in the leg because of limited collateral circulation. Such flaps require one delay or more, a factor that greatly diminishes their usefuhiess”. Whilst this limited collateral circulation in the leg may be partly to blame, there is another factor which influences the fate of these flaps, particularly in the lower third of
0 1
02 FIG. I.
The bipedicle or strap flap. The pedicles are subjected to transverse tension, thus depriving the central part of adequate blood supply. FIG. 2. The sliding transposition
54
flap.
THE
SLIDING
TRANSPOSITION
FLAP
BRITISH
FIG. 4.
FIG. 5.
JOURNAL
OF PLASTIC
SURGERY
Two proximally based flaps used to resurface larger defects.
Excision of an unstable
scar and resurfacing
with z sliding transposition
flaps.
THE
SLIDING
TRANSPOSITION
FLAP
57
the leg. This is the lateral movement of the flap across the convex surface, resuhing in transverse tension with further embarrassment to the blood supply. This tension is often the final insult to a flap already deprived of most of its nutrition, and it may be the cause of necrosis. The bi-pedicle, or “strap” flap (Fig. I) perhaps and undeservedly the most widely used flap in the leg, is similarly at risk. The lateral excursion of this flap on a convex surface subjects the two pedicles to transverse tension. The central part is thus deprived of adequate blood supply, and necrosis then occurs at the very site where good viable tissue is most needed. A safer version of the “strap” flap was described by Crawford in 1957, but this requires two stages. It is interesting to note that whereas local flaps in the leg are affected by this transverse tension, cross leg flaps are safe when inset comfortably on the opposite leg. However, should a cross leg flap be delayed and resutured into its original site, the resultant oedema may cause additional tension leading subsequently to necrosis of part of the flap. Maisels pointed out in 1967 that, should a cross leg flap be delayed, it should be resutured in its retracted position, and the remaining defect covered by a split skin graft. The effect of tension on the survival of skin flaps was proved experimentally by Patterson in pigs in 1971. In this paper we describe a local flap of such design that this transverse tension is obviated by insetting the distal oblique edge of the flap into the contra-lateral side of the
58
BRITISH JOURNALOF PLASTIC SURGERY
defect (Fig. 2), thus sliding the long axis of the flap transversely around the convexity of the limb. TECHNIQUB A healthy and unscarred area of skin i.s selected medial or lateral to the defect (Fig. 3, A). The flap is planned so that its distal oblique edge is as long as the contralateral side of the defect. After raising the flap down to deep fascia (Fig. 3, B) the recipient site is prepared and the flap inset (Fig. 3, c). The flap donor site is then grafted. A fairly obvious dog’s ear can be expected to appear at the base of the flap, but the temptation to trim it should be resisted. It usually readjusts spontaneously, and none of our cases required subsequent trimming. For larger defects two such flaps can be used (Fig. 4). Both flaps are based proximally with their bases on different levels on the limb (Fig. 5). MATERIAL Since Ig6g 13 patients were successfully treated with sliding transposition flaps to repair small to medium-sized defects in the leg. These flaps have also been used in the knee and ankle regions, but these sites are usually favourable for conventional local flaps, and have therefore been excluded from this series. Ages ranged from 18 to 61 with an average of 38. None of the flaps required delay, except I case in which the only flap donor site available was on an old cross leg flap (Fig. 6). Approximately half the cases had defects in the middle third of the leg; the remainder shared equally between the upper and lower thirds. All our flaps survived. Primary healing was achieved in all but I case. In this instance bone infection persisted, a sinus formed, and this required a further procedure, including excision of the infected bone, saucerisation, and skin grafting. CONCLUSION Although local skin flaps are not particularly favourable in the leg, avoidance of transverse tension makes it possible to use local flaps to resurface small to medium-sized defects in I stage. We are grateful to Miss K. Ockendon for the diagrams and to Mr D. Gr@n for the photographs.
REFERENCES CONNELY, J. R. (1968). Reconstructive procedures of the lower extremity, in “Plastic Surgery”, edited by W. C. Grabb and J. W. Smith, p. 784. Boston: Little, Brown & Company. CRAWFORD,B. S. (1957). The repair of defects of the lower limbs using a local flap. British Journal of Plastic Surgery, IO, 32. PATTERSON, T. 1. S. (1971). The effects of tension on the survival of skin flaps. “Transactions of the 5th International Congress of Plastic and Reconstructive Surgery”, p. 807. Australia: Butterworth. SAAD,M. N. (1970). The problems of traumatic skin loss of the lower limbs, especially when associated with skeletal injury. British Journal of Surgery, 57, 604.
