7 Ectropion
Ectropion is a condition commonly encountered in clinical practice. The pathogenesis of ectropion varies. Frueh and Schoengarth (1982), in an excellent paper, succinctly summarized the evaluation and treatment of the six elements of pathology that may be present in an ectropic eyelid. These factors include horizontal lid laxity, medial canthal tendon laxity, punctal malposition, vertical tightness of the skin, orbicularis paresis secondary to seventh nerve palsy, and lower eyelid retractors disinsertion.
The presence of each factor is determined by clinical examination. One or more of these components may be present in an ectropic eyelid. Proper recognition of the underlying anatomic defect will enable the surgeon to select the appropriate surgical procedure for correction. There are many procedures described for the treatment of each of these eyelid malpositions. In this chapter, one technique is recommended for each of the conditions.
HORIZONTAL LID LAXITY
Horizontal lid laxity is most likely a result of stretching of the lateral and medial canthal tendons, rather than actual elongation of the tarsal plate. This produces a redundancy in the lid tissues, causing the lid margin to fall away from the globe. Horizontal lid laxity can be corrected surgically by several procedures. One popular method is full-thickness excision of a wedge of eyelid tissue and closing the defect primarily. One disadvantage of this method of horizontal lid shortening is that it often leads to lateral canthal deformities, such as blunting of the lateral canthal angle. Additionally, a block resection technique often exaggerates the laxity of the medial and lateral canthal tendon and may produce a horizontally narrowed palpebral fissure. More importantly, surgical correction is not aimed at the underlying defect, namely, stretching of the lateral canthal tendon.
In correcting this element of lid malposition, the lateral tarsal strip procedure advocated by Anderson (1979) is preferred. In this technique, the eyelid is shortened at the lateral canthal end of the lid. The advantages of this technique are that (a) surgery is directed at correcting the anatomic defect, (b) there are no marginal lid sutures, (c) the danger of lid notching or misdirected lashes irritating the cornea is avoided, (d) canthal malposition and lid shortening may be corrected simultaneously, (e) the procedure can be performed quickly, and (f) the almond-shaped canthal angle is preserved.
Procedure: lateral tarsal strip
Lidocaine 2% with 1:100,000 epinephrine is injected into the lateral canthal region with a 30-gauge needle. A small amount of anesthetic is also delivered to the periosteum of the lateral orbital rim and the temporal inferior fornix.
The tarsal plate is grasped with a tissue forceps and pulled with sufficient tension in a lateral direction to place the lower punctum slightly lateral to the upper punctum.
Medial canthal tendon laxity is detected by observing the lateral displacement of the lower punctum with lateral traction on the nasal eyelid. When the lower punctum is no longer aligned vertically with the upper punctum and can be displaced to the nasal limbus when the eye is in primary position, the medial canthal tendon should be repaired. It is unusual to find medial canthal tendon laxity alone, without concomitant lateral canthal laxity. The medial canthal laxity should be corrected first, before proceeding with the horizontal-shortening procedure. The aim of medial canthal tendon plication is to restore the anatomic position of the inferior punctum, so that it is in apposition with the globe and tear lake. The technique involves the exposure of the tendon, anchoring the lid nasally and posteriorly and protecting the inferior canaliculus.
Procedure: medial canthal tendon plication
A curved, vertical incision is made over the medial canthal tendon and continued inferiorly to the medial lid margin, about 3 mm below the punctum.
A Bowman probe is placed in the lower canaliculus to identify and protect the structure throughout the operation. Blunt dissection is carried through the orbicularis muscle fibers with a Freer periosteal elevator to expose the medial canthal tendon and the nasal-most end of the tarsus beneath the punctum.
A double-armed 4–0 Polydek suture on an ME-2 half-circle needle is used.