Choice of operation
The two techniques described are used for defects of more than one-third length. The more commonly used is the Cutler-Beard bridge flap ( 17.1 ). The ‘switch flap’ ( 17.2 ), which is less commonly used, can provide an excellent reconstruction of large upper lid defects with the preservation of most of the lashes but a subsequent reconstruction of the lower lid, including the margin, is required. The disadvantage of both techniques, compared with techniques which do not require a bridge between the lids, is that the eye is closed for several weeks between the two stages.
17.1
Cutler-Beard flap
This is a two-stage technique for reconstruction of large full-thickness defects in the upper lid. It may be combined with a glabellar flap for large medial defects (see 15.17 ).
Excise the tumour. Pull gently on the edges of the defect to estimate the residual defect which has to be reconstructed. This is the horizontal width of the bridge flap. Draw a horizontal line 5 mm inferior and parallel to the lash line of the lower lid. Mark the width of flap required on this line and draw two vertical lines as far as the inferior orbital rim.
Incise the skin along the horizontal line. Perforate the full thickness of the lid with stab incisions at the corners of the flap. With a pair of scissors inserted between the stab incisions complete the horizontal full-thickness incision. From the ends of this incision cut vertically down to the inferior conjunctival fornix to create an inverted U -shaped flap. Pull the flap up posterior to the lower lid margin.
Suture the flap into the upper lid defect in three layers: conjunctiva to conjunctiva, and orbicularis muscle of the lower lid to the levator aponeurosis and orbicularis muscle of the upper lid, with interrupted 6/0 or 7/0 absorbable sutures. Finally, use 6/0 interrupted sutures for skin to skin closure. If the conjunctiva of the superior fornix is inadequate a small oral mucosal graft may be inserted; this is rarely necessary. Remove the skin sutures at 5 days if necessary.
After 6 weeks estimate whether the flap has stretched enough to reduce the vertical tension. If it is still tight leave it another 3 weeks. If it has stretched and feels less tight divide the bridge to restore the upper lid margin. To do this pass a squint hook posterior to the flap and carefully incise the layers of the flap making the initial incision convex downwards to allow for retraction. Leave an excess of conjunctiva.
It is not always necessary to suture the conjunctiva over the new lid margin to skin if the margin appears stable. If the lamellae require a suture trim the conjunctiva until it is flush with the skin at the lid margin and use a 6/0 continuous monofilament suture. Remove this at 5 days. Replace the pedicle of the bridge into the lower lid defect and repair it in layers to avoid a fistula through the lid.
See also Fig. 15.17 .
Necrosis of the lower lid margin may occur if the marginal artery was damaged when the flap was cut. Wait until the second stage of the procedure and attempt to close the surviving marginal tissues, with a cantholysis or other procedure if necessary.
The reconstructed upper lid margin is relatively unstable and may become entropic and skin hairs may cause irritation. Insertion of a donor graft, such as sclera, between the layers of the upper lid reconstruction, will improve the stability. This can be done as a secondary procedure if necessary. Inturned skin hairs can be treated with cryotherapy as described in Ch. 8 .
The margin may be irregular at the edges of the bridge flap. Allow the lid to heal and excise the notches if necessary.
17.1
Cutler-Beard flap
This is a two-stage technique for reconstruction of large full-thickness defects in the upper lid. It may be combined with a glabellar flap for large medial defects (see 15.17 ).
Excise the tumour. Pull gently on the edges of the defect to estimate the residual defect which has to be reconstructed. This is the horizontal width of the bridge flap. Draw a horizontal line 5 mm inferior and parallel to the lash line of the lower lid. Mark the width of flap required on this line and draw two vertical lines as far as the inferior orbital rim.