The anterior approach is suitable for larger amounts of retraction; the posterior approach is better for smaller amounts. Since the posterior approach also results in a raised skin crease, it is preferable to restrict its use to bilateral cases.
The principle is that the levator aponeurosis and Muller's muscle are separated from the tarsal plate and recessed. Their position may be maintained with a spacer or with sutures, or left free.
The technique for the anterior approach is as follows (Figure 7.8a and b).
• Make an incision in the upper lid skin crease at the desired level. Deepen it through the orbicularis muscle to expose the full width of the tarsal plate.
• Dissect the skin and orbicularis muscle upwards for about 10-15mm to expose the anterior surface of the orbital septum. To confirm that it is the septum, press on the lower eyelid and look for the forward movement of the pre-aponeurotic fat pad behind it. Incise the septum horizontally to expose the pre-aponeurotic fat pad. Sweep the fat superiorly to expose the underlying levator aponeurosis and muscle.
• Dissect the levator aponeurosis and Muller's muscle from the superior border of the tarsal plate and continue the dissection between Muller's muscle and the conjunctiva as far as the superior conjunctival fornix. The upper lid retractors are now free of their inferior attachments and the tarsal plate can descend freely. If there is persistent retraction laterally, cut the lateral horn of the levator aponeurosis. If it still persists cut the lateral third of Whitnall's ligament and continue to free the tissues laterally until the retraction is overcome and there is a smooth curve to the lid. Decide whether a spacer is to be inserted to maintain the corrected lid position.
• If a spacer is to be inserted (Figure 7.8a), cut the spacer to the size required to allow adequate correction of the lid retraction. It is usually necessary to overcorrect the retraction by 2-3mm. Using 6/0 absorbable sutures, suture the edges of the spacer to the upper lid retractors (levator aponeurosis
-Central and medial
Figure 7.8 (a) Spacer of donor sclera placed between tarsal plate and levator aponeurosis, (b) upper lid retractors recessed and fixed with central and medical hang-back sutures.
and Muller's muscle) superiorly and to the superior tarsal plate border inferiorly.
• If no spacer is to be used (Figure 7.8b), estimate how much recession of the upper lid retractors is required and insert three 6/0 long-acting absorbable or nonabsorbable hang-back sutures.The lateral suture can be omitted if there was difficulty achieving satisfactory correction laterally.
• Close the lid with deep bites to create a skin crease. Insert a traction suture into the upper lid and tape it to the cheek until the first dressing.
The technique for the posterior approach is as follows (Figure 7.9 a and b).
• Place a 4/0 stay suture into the centre of the tarsal plate close to the lid margin. Evert the lid over a Desmarres retractor. Make a short incision through the tarsal plate close to the superior border. An obvious surgical space - the post-aponeurotic space - is entered. Extend the incision medially and laterally, staying close to the superior border of the tarsal plate. The levator aponeurosis is the structure in the depths of the wound (see Figure 7.4).
• Pull down the lower wound edge which includes a strip of the superior tarsal plate and dissect between Muller's muscle
posteriorly and the levator aponeurosis anteriorly. Downward traction on Muller's muscle will expose a "white line" (Figure 7.9a) which is the edge of the levator aponeurosis folded on itself. Incise and turn down the levator aponeurosis for the full width of the tarsal incision to expose, but taking care not to damage the underlying orbicularis muscle (Figure 7.9b). Turn the lid back into its correct anatomical position and assess the correction of the retraction. An over-correction of 2-3mm is usually required. If it is inadequate, dissect superiorly between the levator aponeurosis and the orbicularis muscle for a few millimetres and reassess the lid position. Repeat this until adequate correction is achieved.
• Excise the narrow strip of superior tarsal plate - which is attached to the Muller's muscle. The retractors may be left free. Alternatively, suture them to the orbicularis muscle to fix their position.
• The conjunctiva does not need to be closed. Place a traction suture in the upper lid and tape it to the cheek until the first dressing.
Complications - the lid level, or the curve of the lid margin, may be incorrect. If there is no obvious cause, such as swelling, adjust the level early, within a week or so. If there
of the folded aponeurosis, (b) aponeurosis and septum
of the folded aponeurosis, (b) aponeurosis and septum
Figure 7.9 exposed.
appears to be a probable cause, for example haematoma or swelling, and you think the lid may settle, wait then readjust the level, if necessary, at six months.
An inevitable side effect of an upper lid retractor recession by the posterior approach is that the skin crease is raised. Further surgery may be needed to restore symmetry of the upper lid skin creases and lid folds - either lowering the skin crease in the operated upper lid or raising the skin crease in the opposite upper lid.
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