Introduction
More than any other oculoplastic surgery ptosis surgery depends on a thorough understanding of eyelid anatomy.
Particular care must be taken in the assessment because not all ptosis should be corrected surgically.
Classification
Myogenic:
Isolated congenital ptosis (congenital levator dystrophy)
Blepharophimosis syndrome
Progressive external ophthalmoplegia
Myasthenia gravis
Neurogenic:
Third nerve palsy
Horner’s syndrome
Marcus Gunn jaw-winking
Aberrant regeneration of third nerve
Aponeurotic:
Defects in levator aponeurosis
Mechanical:
Dermatochalasis
Tumour
Scar
Anophthalmos
In the assessment of ptosis (see techniques in Ch. 3 ), measure the amount of ptosis using the margin–reflex distance, the levator function, the skin crease level from the lid margin, the eye movements and the presence of Bell’s phenomenon. Check for jaw-winking.
If there is weakness of elevation of the eye on the affected side, with hypotropia, the position of the eye must be corrected first before embarking on ptosis surgery. The ptosis often improves and ptosis surgery is occasionally no longer required. This can be checked by covering the normal eye ( Fig. 9a , b ).
Correction of unilateral ptosis, especially in the older age group, may reveal a hidden ptosis on the opposite side. Hering’s law applies. Check preoperatively by lifting the ptotic lid to assess a contralateral drop ( Fig. 9c , d ). This test is not totally reliable and patients should always be warned of the possibility of a ptosis developing on the opposite side following unilateral surgery.
Check for fatigue in suspected myasthenia (see 3.7 ).
A phenylephrine test (see 9.5 ) may be helpful before Müller’s muscle resection. Check the vision and, where relevant, assess the pupil reactions and the adequacy of tear production. Finally, examine the fundi.
Choice of operation
– Levator aponeurosis repair
– Levator resection
– Müller’s muscle shortening
– Brow suspension
Dehiscence of the levator aponeurosis is characterised by moderate ptosis with good preservation of levator function. The skin crease is usually higher than normal, there is a deep upper lid sulcus and the lid tissues may appear thinned. Most patients are in late middle age or beyond, some have a history of intraocular surgery and some younger patients have a history of contact lens wear. Repair of the levator aponeurosis is described in Sect. A .
Levator resection is described in Sect. B . It is suitable for any amount of ptosis with a levator function better than 4 mm.
Müller’s muscle shortening is described in Sect. C . The Fasanella-Servat operation was the first operation of this type. The upper tarsal border was included in the excision of Müller’s muscle. However, in the more recent Müller’s muscle shortening operations the tarsal plate is not included. These operations are appropriate only if the levator function is at least 10 mm and there is a maximum of 2 mm of ptosis. The phenylephrine test can be helpful in assessing these patients (see Sect. C ).
Brow (or frontalis) suspension is described in Sect. D . It is the only procedure which will give a lasting correction if the levator function is 4 mm or less.
These general rules must be used with care if there is any weakness of eyelid closure, abnormality of eye movements or reduced tear production. In these patients there may be an increased risk of corneal exposure.
Lid level at operation
Following levator aponeurosis advancement or levator muscle resection the level of the eyelid may change during the first 6 weeks. As a rule-of-thumb the lid may rise by 1 to 2 mm if the levator function is >7 mm and may drop by 1 to 2 mm if it is <7 mm. The lid level can be expected to remain at its immediate postoperative level if the levator function is about 7 mm. In addition, the lid height may change a little from the level set at operation to that found at the first dressing. The local anaesthetic injection and swelling of the tissues may distort the lid level at operation and the action of the orbicularis muscle, paralysed to a variable degree during the operation, may cause a small drop in the lid level postoperatively.
These factors make it difficult to decide exactly where to set the lid at operation and how much levator to resect. Beard’s recommended figures for congenital ptosis give some guidance. They apply mainly to congenital ptosis but offer guidance for other ptosis corrections ( Table 9.1 ). The aim is to achieve a lid level after operation of 1 to 3 mm from the upper limbus depending on the levator function. Other factors are relevant in a small number of patients.
| Degree of ptosis | Levator function | Resection |
|---|---|---|
| Mild (<2 mm) | >10 mm | Small (10–13 mm) |
| Moderate (3 mm) | >8 mm | Moderate (14–17 mm) |
| <8 mm | Large (18–22 mm) | |
| Severe (>4 mm) | <5 mm | Maximum (>23 mm) |
Levator aponeurosis repair
9.1
Anterior levator aponeurosis repair (advancement) ( ) 
The upper lid skin crease is usually raised by a levator aponeurotic defect. At operation a new skin crease is made 6 to 8 mm from the lash line.
See also 10.2 in which an anterior levator aponeurosis repair is combined with a planned blepharoplasty.
Mark the skin crease symmetrical with the opposite side or at the desired level in bilateral cases. Make an incision through the skin to expose the underlying orbicularis muscle. Lift the skin edges at either side of the wound with fine toothed forceps and deepen the wound through the orbicularis muscle until the tarsal plate is exposed throughout the length of the incision. Take care not to stray down toward the lashes or upwards above the upper tarsal border.
Identify the orbicularis muscle layer in the upper wound edge. Immediately deep to this layer is the white levator aponeurosis, the lower end of which was probably cut while deepening the first incision. A traction suture (9.1c) may be placed through the tarsal plate at this stage to stabilise the lid while dissecting the orbicularis muscle.
Dissect upwards immediately posterior to the orbicularis muscle for about 10 to 15 mm to expose the orbital septum. Take care that this dissection is in the correct plane and not in the deeper, easier plane between the levator aponeurosis and Müller’s muscle (see Diag. 1.16 ). When the dissection is in the correct plane the posterior surface of the orbicularis muscle fibres can be seen clearly without any overlying sheet of tissue. It may also be possible to see the whitish-yellow preaponeurotic fat pad through the orbital septum. Pressure on the lower eyelid will make the fat pad prolapse the septum forward. If it is not visible, further dissection superiorly will often bring it into view.
Having dissected the orbicularis muscle upwards the anterior surface of the levator aponeurosis and the orbital septum may be inspected. The septum inserts into the anterior surface of the aponeurosis a few millimetres superior to the upper tarsal border. A definite transition from healthy, white aponeurosis (above) to attenuated aponeurosis (below) is often visible just inferior to this insertion. Occasionally a definite defect can be identified in the aponeurosis. Müller’s muscle, with overlying vessels, is visible through the attenuated aponeurosis.
Make a buttonhole through the centre of the septum, over the visible preaponeurotic fat pad, to enter the preaponeurotic space. Extend this medially and laterally to expose the preaponeurotic fat pad (arrow) and the anterior part of the levator muscle deep to it (9.1e).
Gently retract the preaponeurotic fat to allow inspection of the levator muscle and to expose Whitnall’s ligament lying transversely across the levator muscle just superior to the origin of the aponeurosis, approximately 10 to 15 mm above the tarsal plate. Incise the attenuated aponeurosis over the upper part of the tarsal plate and carefully dissect it from the underlying Müller’s muscle until the thicker, white aponeurosis is reached. Compared to the anterior surface, this is easier to identify from the deep, posterior aspect of the aponeurosis. Grasp the tissue overlying the tarsal plate and gently lift the lid superiorly to check the curve of the elevated lid. Repeat this at different points until a satisfactory curve is achieved. Bring the edge of the healthy, white aponeurosis to the tarsal plate and fix it at this point, 2 to 3 mm below the upper border, with a single 6/0 absorbable suture placed 2 to 3 mm within the healthy aponeurosis. Ask the patient to look ahead and assess the lid level. It will often be found to be correct. If it is too low or high adjust the height by moving the position of the suture in the levator aponeurosis.
Place medial and lateral sutures and check that the curve of the lid margin is satisfactory. If it is not, adjust the position of these sutures.
Note – It is not always essential to open the orbital septum when repairing an aponeurosis if healthy aponeurotic tissue is clearly visible inferior to the insertion of the septum. However, opening it helps to confirm the anatomy if there is any doubt. It also releases the preaponeurotic fat and prevents a double skin crease.
If there is excess skin above the wound, mark the skin to be removed and excise it with scissors. Begin the excision with a central vertical cut from the wound edge. Alternatively, a planned excision of excess skin can be marked at the start of surgery (see 10.2 ).
A Frost (traction) suture (see 2.22a ) may be inserted into the lower lid and taped to the brow to protect the cornea under the dressing but is not usually necessary.
9.2
Posterior levator aponeurosis repair (advancement) ( ) 
Mark the skin crease as described previously for Fig. 9.1 , evert the lid and place a stay suture through the tarsal plate close to the lid margin. Insert a Desmarres retractor and evert the lid over it to stabilise the tarsal plate. Make a short transverse cut through the centre of the tarsal plate close to the superior tarsal border, approximately level with the skin crease. The postaponeurotic space, an easily identified surgical space, will be entered (see Diag. 1.17 ).
Enlarge the incision in the tarsal plate transversely, parallel to the lid margin, extending it into the conjunctiva medially and laterally. The (postaponeurotic) space now exposed has the levator aponeurosis in its roof and Müller’s muscle in its floor.
Separate the loose connective tissue to enlarge the postaponeurotic space about 10 mm. By pulling down on the lower wound edge traction is exerted on the attachment of Müller’s muscle to the levator. This creates a fold in the levator aponeurosis which is seen as a ‘white line’.
Remove the Desmarres retractor. It may help to replace it over the everted tarsal plate. Pull the cut edge of the levator aponeurosis downwards. The septum and its insertion into the aponeurosis are now visible. The anatomical orientations of the septum and levator are now as they are in an anterior approach (9.1). Incise the septum transversely (see Figs 9.1c , d , 9.4a–c and note on Fig. 9.8d ) to expose the preaponeurotic fat pad and the underlying levator muscle with Whitnall’s ligament (see Fig. 9.8e ).
Note – As in an anterior approach aponeurotic repair it is not always essential to open the septum. It can, however, be opened to confirm the anatomy or to identify healthy aponeurosis if it is not found where expected.
Keeping in line with the centre of the tarsal plate pass both needles of a double-armed nonabsorbable suture posteriorly through healthy aponeurosis close to its cut edge, then through the cut edge of the conjunctiva and Müller’s muscle.
Tie a temporary knot and ask the patient to look ahead. Adjust the level of the suture in the aponeurosis until the level is satisfactory. Place two more double-armed sutures in the same way and adjust as before to achieve a satisfactory eyelid curve.
Tie all three sutures over small cotton wool bolsters. The presence of the bolsters may distort a previously acceptable lid curve; this effect will be reversed when the sutures are removed. A Frost (traction) suture may be inserted to finish.
Remove the sutures after 2 weeks. It the lid is too high postoperatively they should be removed after 2 or 3 days. Lid massage or eyelash traction for 1 minute, three times a day will encourage the lid to drop a little. This can be continued until symmetry with the opposite upper lid is achieved.
Levator resection
9.3
Anterior levator resection ( ) 
Keeping upward tension on the brow to flatten the tissues dissect superiorly on the deep surface of the orbicularis muscle, between the muscle and the septum as described in 9.1a,b, to expose the septum for 10 to 15 mm. Apply pressure on the lower lid to prolapse the preaponeurotic fat pad posterior to the septum.
Make a buttonhole through the septum to enter the preaponeurotic space (see 9.1d ). Extend this medially and laterally to expose the fat pad and the anterior part of the levator muscle deep to it.
Gently retract the preaponeurotic fat to allow inspection of the levator muscle and to expose Whitnall’s ligament lying transversely across the levator muscle just above the origin of the aponeurosis, approximately 1 cm above the tarsal plate. If the levator function was significantly reduced preoperatively a moderate amount of fatty infiltration will be found partly obscuring the levator muscle fibres.
Return to the superior border of the tarsal plate and detach the lower limit of the levator aponeurosis from the superior border of the tarsal plate. This exposes the attachment of Müller’s muscle to the superior tarsal border.
Separate Müller’s muscle from the superior tarsal border. Insert a corneal protector during cautery of the vessels on the surface of Müller’s. Dissect Müller’s muscle and the overlying aponeurosis together from the conjunctiva to the level of the conjunctival fornix. The superior suspensory ligament of the fornix is usually visible as a whitish thickening within the conjunctiva at the level of the fornix.
Return to the inferior edge of the levator aponeurosis and identify the medial and lateral horns. If less than about 13 mm resection of Müller’s muscle and levator is anticipated to correct the ptosis, the horns may be left intact. However, if more than this is required, the horns should be cut. If the horns are not to be cut, proceed to 9.3n.
Cutting the horns of the levator aponeurosis (Different case)
To cut the medial horn, direct the scissors slightly laterally towards the levator muscle to avoid damage to the trochlea. To cut the lateral horn, direct the scissors slightly medially to avoid damage to the lacrimal gland. Take care not to cut Whitnall’s ligament.
Placing the sutures
The amount of resection of the levator aponeurosis (with or without Müller’s muscle) can be estimated preoperatively ( Table 9.1 ). The correct amount will result, at operation, in a lid level 1 to 3 mm below the upper limbus (see Lid level at operation , p. 177 ). To reattach the levator to the tarsal plate, place a 6/0 absorbable suture through the centre of the aponeurosis (or levator muscle, depending on the amount to be resected) at the level of the anticipated resection and attach it to the tarsus 2 to 3 mm from its upper border with a temporary knot and assess the height of the lid. If necessary, reinsert the suture until a satisfactory height is achieved. If the levator aponeurosis has been resected without Müller’s muscle, overcorrect the lid height slightly.
If a very large resection is needed this can be reduced by placing the levator over Whitnall’s ligament (9.3y,z).
A very large levator resection would reduce the amount of functioning levator muscle. By placing the levator over Whitnall’s ligament the fulcrum of action of the levator is raised and less muscle needs to be resected to achieve the same effect.
Carefully dissect the muscle from beneath Whitnall’s ligament. Begin by cutting the muscle sheath transversely above and below Whitnall’s.
Alternative procedure
Levator aponeurosis resection without Müller’s muscle
An alternative to the dissection of Müller’s muscle and levator aponeurosis together, is to dissect the levator aponeurosis alone. To do this, dissect between the aponeurosis and Müller’s muscle until the origin of Müller’s muscle from the posterior surface of the levator is reached approximately 1 cm above the tarsal plate. Make a transverse incision, directed posteriorly towards the conjunctiva, through Müller’s muscle at this point to detach it from the levator, taking care not to damage the levator. The underlying conjunctiva close to the upper fornix is exposed. The levator aponeurosis may now be advanced without Müller’s muscle. This variation is usually reserved for small degrees of ptosis with good levator function.
9.4
Posterior levator resection
With gentle downward traction on the cut conjunctival edge, dissect the levator and Müller’s muscle from the conjunctiva as far as the superior fornix. Identify the horns by transverse traction on the edge of the aponeurosis (see Fig. 9.3j ) and cut them if necessary (see comment 9.3j ).
