The visor flap: Preservation of length in finger amputations

Abstract

M ethods of closure of the amputated finger stump are legion. Certain levels of amputation, however, demand preservation of length for optimum function. The visor flap provides this, together with sensation, padding and scars that avoid volar pressure points. The design of the flap follows the principles of three-dimensional rather than plane geomery. PRINCIPLES OF FLAP DESIGN The visor flap is a bipedicled flap based on the dorsal branches of the volar digital neurovascular bundles (Figure 1). Transverse amputations of the distal, middle and distal proximal phalanges are most suitable for this technique. Figure 2 illustrates the design of the dorsal flap. The volar/dorsal diameter of the amputation site is measured (A-B). To achieve adequate coverage, a similar area of dorsal skin and subcuta-neous tissue must be obtained (A-C), therefore, A-B is equal to A-C. The extent of the lateral incisions are to the mid axial line (D). The pivot point, D, restricts the volar transposition of this bipedicled flap because C-D is shorter than A-C. Therefore, a back cut (Figure 3) is made so that AD 1 is equal to C-D 1. The new pivot point of D 1 allows adequate volar transposition of the flap. The back cut must be through dermis only to avoid potential damage to the neurovascular structures in the subcutaneous plane. The dissection is deepened down to but not through the paratenon level. The flap is undermined and transposed distally, and sutured with a nonabsorbable suture. The donor defect is covered with a split thickness skin graft and dressed appropriately: excess skin (dog ears) may be prominent laterally, but these should not be tailored because this may interfere with the neurovascular supply to the flap. Physiotherapy to maintain range of motion is initiated on postoperative day 7. Skin graft maturation and contraction aids in the resolution of the dog ears and acts as a force in drawing the volar scar dorsally, leaving a volar surface free of a potentially prominent and/or painful scar line.