1.4.2 Direct Excision of Lashes

Distiatic lashes can be removed by direct cut down and excision of individually targeted lash follicles through a tarso-conjunctival trap door or a lash margin split [25, 74]. The access can be obtained even more simply by direct cut down. This should ideally be performed with the surgeon wearing loupes or under a microscope. After infiltration with vasoconstrictive local anaesthetic, the lid is everted over a Desmarres retractor using a 4/0 nylon traction stitch. Alternatively, the lid can be immobilised with a chalazion clamp. The lashes to be targeted are identified. A direct cut down is performed onto the shaft with a feather blade, such as those used for corneal paracentesis. The shaft and its follicle are thus exposed and can be electrolysed and excised (Fig. 1.12). The surgical incision heals rapidly and the patient is treated with topical antibiotic ointment nightly for 1 week.

1.5 Ptosis

1.5.1 Introduction

Ptosis is one of the most common reasons for an oculoplastic referral. In primary gaze, the upper lid margin normally sits at a level of 1–2 mm below the upper limbus. An upper lid is said to be ptotic when its margin is

Fig. 1.12 Electrolysis to lash root under direct vision

lower than this. It may block part of the upper field of vision and if severe enough will obscure the visual axis. Its aetiology is varied and acquired cases are classified as due to aponeurotic defects (by far the most common), or are neurogenic (e.g. third nerve palsy, Horner’s syndrome, myaesthenia), myogenic (e.g. ocular myopathy, external ophthalmoplegia) or mechanical in origin [8].

Various well-established surgical methods have been described for the correction of ptosis. The choice of procedure is based on the degree of ptosis and perhaps more importantly the strength, or lack of it, of levator function [19]. In cases of age related aponeurosis dehiscence, where levator function is good and the ptosis is mild, minimally invasive repairs can be done either by the posterior or anterior approach.

1.5.2Posterior Approach Muller’s Muscle-Conjunctival Resection

In patients with a small ptosis and good levator function, the ptosis can be repaired through a posterior approach by excision of Muller’s muscle and conjunctiva. This was first popularised by Putterman over 30 years ago and has enjoyed a renaissance of late [60].

Patient evaluation: this procedure is best used for mild involutional ptosis of 2 mm or less, with good levator function of 10 mm or more. It can be done unilaterally or bilaterally. It is not an appropriate procedure for patients with traumatic levator dehiscence, nor for ptosis from causes other than age related involution (e.g. neurogenic or myogenic), nor in patients with poor or absent levator function. Ptosis is gauged by measuring the vertical palpebral aperture in primary gaze, i.e. the distance between the upper and lower lid margins at the mid-pupillary line. The palpebral aperture has upper and lower components, the MRD1 and MRD2 respectively. MRD stands for margin-reflex distance and is the distance from the light reflex in the mid-pupil to the upper lid margin (1) and lower lid margin (2). The combined measurements of MRD1 and MRD2 equal the palpebral aperture (Fig. 1.13). Levator function is documented by measuring the upper lid margin excursion from downgaze to upgaze with a millimetre ruler held vertically in the mid-pupillary line, while preventing any brow elevation by pressing on it.

Patient selection: to assess whether a conjunctival – Muller’s muscle excision is likely to be effective,

Fig. 1.13 MRD margin reflex distance. 1: superior; 2: inferior. Illustration by Christiane Solodkoff, Neckargemünd/Heidelberg, Germany

measurements are taken as indicated above. Then one drop of 2.5% phenyephrine is instilled in the superior fornix of the patient’s ptotic lid. After a period of 5 min, measurements are taken again. If the height of the previously ptotic lid now matches the contralateral normal side in unilateral cases, or the heights of both previously ptotic lids are now normal, then this procedure is advisable and 8 mm of Muller’s muscle and conjunctiva can be excised; if the lid is too high, the excision should be reduced to between 6.5 and 8 mm; if a millimetre too low then 8–9.5 mm should be excised. If the ptotic lid response is inadequate, a levator aponeurosis advancement or repair should be considered.

Method: after instillation of local anaesthetic at the lid margin, without any vasoconstrictive agents, and

a

c

Fig. 1.14 Muller’s muscleconjunctival resection.

(a) 6.5 mm measured between cautery marks; (b) suturing above clamp; (c) resection done and suture about to be tied

topical anaesthetic drops to the conjunctival surface, the lid is everted on a Desmarres retractor by a traction stitch through the lid margin. The amount to be resected is marked on the conjunctiva with small cautery burns. Three sutures are placed half way between these marks to tent up the conjunctiva and Muller’s muscle away from the aponeurosis. The tent is then clamped just shy of the cautery marks. A double armed absorbable suture (e.g. 6/0 Vicryl) is sewn in mattress fashion, 1 mm above the clamp edge, to allow room for a D15 blade to shave the clamp and its tissues off the lid once the mattress suture is in place. The unused half of the doublearmed stitch then oversews the cut edge and is tied on the end of the first half (Fig. 1.14). Antibiotic ointment is instilled, and as many surgeons pad the eye for a few hours afterwards as don’t. At review, if the new lid height is too high, the lid is everted after instillation of topical anaesthetic drops and the suture removed and the wound edges opened slightly. If the height is undercorrected, the surgery should be repeated with an alternative procedure which involves the aponeurosis.

1.5.3Anterior Approach – One Stitch Aponeurosis Repair

Patient selection: if the ptosis is more than 2 mm, but still mild to moderate (3–4 mm) and in the presence of normal levator function, then an aponeurosis repair or

b

Fig. 1.15 One stitch aponeurosis repair. (a) Anterior surface of tarsus exposed; (b) aponeurosis edge advanced; (c) edge sutured to tarsus

c

advancement is desirable. In an otherwise healthy lid with no previous surgery, this can be achieved through a small incision, allowing just one stitch to reattach the aponeurosis [10, 33, 45].

Method: the level of the incision is selected preoperatively with a marker pen. The skin incision needs to be short and match the skin crease level of the unaffected contra-lateral side. When performing this procedure bilaterally, the skin incisions need to match. A small amount (1 mL) of vasoconstrictive (1:200,000 adrenaline) local anaesthetic is injected in the sub orbicularis/pre tarsal space under the skin crease mark and massaged in. The incision is duly made at the marked site and the orbicularis fibres are separated by blunt dissection until the anterior surface of the tarsus comes into view. The dissection is then continued superiorly. This will lead to the exposure of the conjunctiva as the aponeurosis has thinned or even detached. Dissection further up will reveal the reflected edge of the dehisced aponeurosis and this is reattached to the top of the tarsus with one non-absorbable suture (e.g. 6/0 nylon) or a thicker long acting absorbable suture (e.g. 5/0 vicryl) on a bow (Fig. 1.15). The new height of the lid is assessed with the patient looking in primary gaze and adjusted until satisfactory. Once the desired level is achieved, the tarsal suture is tied and

the skin closure made with a fast-acting absorbable stitch such as 7/0 vicryl rapide.

This method is ideal for patients with high sulci as it leaves the pre-aponeurotic fat pad undisturbed. In those with full/hooded lids, the reflected edge of the aponeurosis is opened; blunt dissection anterior to it will release the fat pad, enabling it to drop to the level of the skin incision. If a considerable amount of aponeurosis has disintegrated, the stitch reattaching its healthy remnant to the tarsus may need to be on a hangback to compensate for the loss of tissue, as reattaching it directly will be equivalent to a resection, thereby raising the lid too high.

Suture selection: If the incision is to become the skin crease, the skin closure stitch should include the aponeurosis (or the tarsus if the aponeurosis is on a hangback) to match the skin crease of the contra-lateral unaffected side. The skin is closed with one or two fast dissolving sutures such as 7/0 vicryl rapide. If the skin incision is not to be the skin crease (as in patients with high sulci), the incision can be closed directly with sub-cuticular nylon to minimise scarring or fast dissolving sutures.

If the tissues are thin and friable or of poor quality, the post-operative inflammatory response and subsequent scarring may be less than can normally be expected. A dissolving suture may therefore weaken before sufficient

reparatory fibrosis has set in. Under these circumstances it may be preferable to use a permanent suture, such as 6/0 nylon to reattach the aponeurosis edge to the tarsus, whether this be directly or on a hangback.

1.5.4 Supramid Brow Suspension

If the ptosis is severe and there is poor levator function (4 mm or less), surgery on the clearly weak levator muscle will be ineffective. The patient often relies on lifting the brows (frontalis recruitment) to help lift the ptosis to clear the visual axis. Brow suspension procedures harness this reflex frontalis muscle action and transfer its power to the tarsus by connecting to it with various materials. The ideal material is the patient’s own tissue and the use of fascia lata from the thigh is well established [23].

Patient selection: there are times when the harvesting of autogenous fascia lata is not possible. A child may be too young for the leg to be long enough to harvest enough material. In some adults, a general anaesthetic may be undesirable either because of health reasons or because the patient prefers not to have one. The patient may wish to avoid a second site of surgery, i.e. the leg. In patients who are at high risk of corneal exposure (external ophthalmoplegias and ocular myopathies), the suspension may need to be reversed. In all these circumstances, synthetic materials are used [16, 26, 41, 44, 49, 64]. Fascia lata and many synthetic materials are introduced and placed in the lid and brow

a

tissues with a large needle (Wright’s fascial needle). They are often relatively thick and not without complications such as slippage, extrusion and granulomas. Supramid also carries these risks but is thinner and easier to insert, with quicker surgical turnover and less recovery period required for the patient. It is a nonabsorbable synthetic suture of the nylon variety (polyamide). Originally proposed as a replacement for fascia lata, long term studies showed it not to be as effective but nevertheless remained very useful in the shorter term particularly in high risk patients [40]. It consists of a cable, or core, and a very smooth polyamide sheath. This allows it to glide easily through the tissues on insertion. An even greater advantage is its needle. It is an integral part of the stitch, whereas other materials need threading; it is much smaller than that used to insert the other materials mentioned above, and it has the right curvature and length for a brow suspension.

Method: Vasoconstrictive local anaesthetic is injected along the tracks of the suspension material. Local anaesthetic is also infiltrated in children having a general anaesthetic as it helps greatly with post-opera- tive discomfort. Using the Fox technique, 5 small stab incisions are made at each angle of the pentagon, with a straight blade (e.g. E11). Two stab incisions through pretarsal skin and orbicularis are usual. These can be extended into a longer single incision made down to the anterior tarsal surface, thus allowing suturing of the stitch to the tarsus to prevent slippage. Of the remaining three stab incisions, two are placed at the top of the brow, and one in the forehead (Fig. 1.16). These three form an isosceles triangle which is the most efficient

b