Step-advancement island flap for fingertip reconstruction

Brirrsh Journa/ofFlasric Surgery(1988),41, 105-111 c 1988The Trustees of British Association of Plastic Surgeons

Step-advancement reconstruction

island flap for fingertip

D. M. EVANS and D. L. MARTIN Department of Plastic Surgery, Wexham Park Hospital, Slough, Berkshire

Summary-An island flap is described for fingertip reconstruction, based on one neurovascular bundle. The design incorporates the stepladder principle, which ensures the provision of ample skin with full tactile sensibility in the required position, without the risk of longitudinal volar scarring and with good nail support when necessary. Fourteen such repairs have been carried out with satisfactory results and no complications

The advancement of a nemovascular island flap to repair fingertip damage is a well established technique (Joshi, 1974; Venkataswami and Subramanian, 1980; Schuind et al., 1985). Theoretically the entire side of the finger could be advanced distally, based on one neurovascular pedicle, but the use of long island flaps carries the disadvantage of a longitudinal midline volar scar with the attendant risk of flexion contracture. To overcome this problem and yet be able to utilise large flaps to reconstruct defects requiring up to 2 cm of advancement, we have applied the step-advancement principle, previously described as a means of reconstruction of the lower lip (Johanson et al., 1974; Sullivan, 1978) and nose (Hallock and Dreyer, 1987). This technique of repair is applicable to defects of the fingertip which are too large to allow simple skin closure or volar VY advancement (Atasoy et al., 1970) without distortion of surrounding structures, and which are too deep to allow the use of a free skin graft without adhesion to underlying bone or loss of satisfactory tactile pulp. The digit must have two patent digital arteries, confirmed by the digital Allen’s test or Doppler examination, and the requirement for advancement should not be more than 2 cm. It is not advisable to use the technique in the elderly or in arteriopaths or heavy smokers. It provides tissue to support the nail if that has been preserved, and allows stump coverage without shortening in more proximal amputations. Technique The repair should be carried out under regional block or general anaesthesia, and arm tourniquet 105

control. The flap is raised on whichever side of the digit provides it most readily, but the least used side of the finger is preferred. The design of the flap is critical, the distal segment being the key area, since this provides cover for the original fingertip defect (Fig. 1A). The volar incision, which is made first, comprises three triangular flaps, narrow proximally and wide distally. The distal wide triangle just crosses the midline to poach slightly from the other side of the digit, but the proximal flaps are confined to the affected side. These triangles are not separated from the underlying subcutaneous fat, but the corresponding triangles based on the other side of the digit are raised thinly so that a longitudinal subcutaneous dissection can be made in the midline of the finger, protecting the neurovascular bundle. The dorsal incision is gently convex, maintaining adequate width at the narrow segments and coming to a point proximally with a triangular flap on the line of the neurovascular bundle. The island flap is now raised from distal to proximal on the plane deep to subcutaneous fat, keeping the neurovascular bundle with the skin. Small branches have to be divided, but if a larger dorsal branch is encountered running distally it can be preserved since it will slacken as the flap moves distally. The network of fibrous tissue that tethers the skin to the underlying structures has to be freed and as the proximal pole of the flap is reached this dissection should be carried more proximally so that the neurovascular bundle is mobilised. The incision can be extended proximally in the midlateral line to achieve this. Only when the neurovascular bundle is completely mobile can the dissection be considered complete. This phase is time-consuming and should be done with some

106

BRITISH JOURNAL OF PLASTIC SURGERY

Fig. 1 Figure l-(A) Design of a flap to replace loss of most of the pulp due to a dog bite, initially grafted. A volar-oblique defect such as this can be replaced if the distal segment of the flap is large enough, which means that the proximal part of the flap extends into the proximal section of the digit. The triangular flaps become narrower more proximally. The incision is extended to allow neurovascular dissection. (B) The flap has advanced distally by 2 cm. Note the volume of convex tissue that is available. Each triangular flap has moved distally one step. The two proximal triangular defects have been closed. The dorsal incision is allowed to gape, avoiding tension in the flap, and the PIP joint has been allowed to adopt a flexed position. This must be actively corrected by 5 days, or more active splintage may be needed to regain full extension.

1

magnification to be sure of avoiding damage to the digital nerve or artery or its minute accompanying veins. It should now be possible to advance the flap, engaging each triangular flap one step distally (Fig. 1B). If it will not move far enough the neurovascular bundle should be further freed, dividing every last strand of fibrous tissue that tethers it. Some PIP joint flexion can be allowed to feed the flap distally, and provided this is fully extended at 5 days there need be no fear of flexion contractures. Nevertheless this complication must be consciously avoided. The tourniquet is released and the circulation checked. The flap should fill rapidly. Suturing commences at the points and angles of the volar zig-zag. The gap left by the proximal triangle is closed, as is the proximal angle left by distal advancement of the flap. The distal segment of the flap is sutured into the tip defect where it should restore the proud convexity of the fingertip pulp. Finally the dorsal incision is sutured, though it is usually found that complete skin-edge apposition is impossible. A gap of up to 4 mm is acceptable and will heal down to a narrow scar. The flap must not be put under tension. Results Fourteen flaps have been used in 13 patients. There has been no loss of any part of the flap and healing has been uneventful in every case. The distribution by digit is shown in Figure 2.

?

I

: :

: /

I

\\, Fig. 2

Figure 2-The

distribution of flaps by digit.

:I

/

/ R

/’

1”

,,,,--

)

1

/ ;

STEP-ADVANCEMENT

ISLAND FLAP FOR FINGERTIP

RECONSTRUCTION

107

Fig. 3 Figure 3-_( A) Use of the flap for transverse fingertip loss with nail preservation. (B) The design of the flap. The bone has not been shorter ned. (C) The flap raised, with only the neurovascular bundle still connected. (D) The flap sutured in place. Nail SL‘PPCuting matrix has been replaced as a free graft, and the tip of the flap forms part of its bed. (E) The final result. with a good I sea r, no contra1 eture and a convex tip. (F) Regrowth of the nail.

108

BRITISH JOURNAL

OF PLASTIC SURGERY

Fig. 4

Fig. 5 Figure 4-(A) Amputation of two fingertips proximal to the nail, with preservation of the DIP joint. The parts were not suitable for replantation. (B) Two ulnar-sided flaps have been used, achieving closure without any bone shortening. (C) There is a 5 cm dorsal gap. (D) Satisfactory fingertip restoration with full motor and sensory function. (E) The benefit of maintaining skeletal length is clear. Figure 5-(A) and(B) The result after use of the flap to repair thumb-tip loss.

STEP-ADVANCEMENT

ISLAND FLAP FOR FINGERTIP

RECONSTRUCTION

109

Fig. 6 Figure 6-_(A) simultaneous elective reconstruction of two scarred fingertips. A step-advancement island flap has been designee II on the fad ha1 side of the middle finger. (B) A cross-finger flap has been designed with its base on the ulnar side of the same finger and its tip I-caching the dorsal edge of the island flap defect. This flap was transferred to replace the pulp of the ring finger. (C) and (D) The tw ‘0 healed flaps on middle and ring fingers. The Wolfe graft used to repair the cross-finger flap defect extended to the edg re of the isla nid flap.

BRITISH JOURNAL OF PLASTIC SURGERY

Fig. I Figure 7-(A) Elective use of the flap to replace a scarred amputation stump with a chronic fissure in a plumber. (B) The flap raised. (C) Distal advancement of the flap. (D) A satisfactory smooth finger stump.

STEP-ADVANCEMENT

ISLAND

FLAP FOR FINGERTIP

111

RECONSTRUCTION

Eight repairs were carried out as emergencies and six were elective. In one case a cross-finger flap was raised from the dorsum of the same finger, based on the opposite side, for transfer to the neighbouring finger. Representative examples are shown in Figures 3-7. The patients have been examined 3 months or more after the repair. All were satisfied and used the digits without difficulty. None complained of tender scars on either dorsal or volar edges. All but two patients had normal sensation and sweating, while two reported reduced sensation, though some sensation was present and sweating normal. In these two patients, 2-point discrimination was 10 mm. The circulation was normal, all the volar zig-zag scars were inconspicuous and free of contractures and the dorsal scars trouble free. Finger movements were normal though one recent patient had delayed restoration of PIP extension due to poor out-patient supervision, and splintage was required to regain full extension. This case underlined the need for close attention to PIP joint extension at about 5 days. Acknowledgements We are grateful to Mrs Rita Hanson for secretarial help in preparing this paper, Mrs Jean Tyler for help with the illustrations, and other members of staff at Wexham Park Hospital for help in treating these patients. The authors acknowledge the generous contribution made by Princess Margaret Hospital, Windsor, towards the cost of reproducing the colour photographs.

References Atasoy, E., Ioakimidis, E., Kasdan, M. L., Kutz, J. E. and Kleinert, H. E. (1970). Reconstruction of the amputated finger tip with a triangular volar flap. A new surgical procedure. Journal of Bone and Joint Surgery, 52A, 92 1. Hallock, G. G. and Dreyer, T. M. (1987). The stair-step flap for nasal reconstruction. Annals of Plastic Surgery, 18. 34. Johanson, B., Aspehmd, E., Breine, U. and Holmstriim, H. ( 1974). Surgical treatment of non-traumatic lower lip lesions with special reference to the step technique. Scandinavian Journal of Plastic and Reconstructive Surgery, 8, 232. Joshi, B. B. (1974). A local dorsolateral island flap for restoration of sensation after avulsion injury of the fingertip pulp. Plastic and Reconstructive Surgery, 54, 175. S&rind, F., Van Gene&ten, F., Dennit, P., Merle, M. and Foucher, G. (1985). Homodigital neurovascular island flaps in hand surgery. Annals of Hand Surgery, 4,306. Sullivan, D. E. (1978). “Staircase” closure of lower lip defects. Annals of PlasticSurgery, I, 392. Venkataswamy, R. and Subramanian, N. (1980). Oblique triangular flap: a new method of repair for oblique amputations of the finger-tip and thumb. Plasticand Reconstructive Surgery, 66,296.

The Authors D. M. Evans, FRCS, Consultant Plastic Surgeon, Wexham Park Hospital, Slough, Berkshire SL2 4HL. D. L. Martin, FRCS, Registrar in Plastic Surgery. Nottingham City Hospital, Nottingham. Requests

for reprints

to Mr D. M. Evans

Paper received 3 June 1987 Accepted 23 June 1987.