Canthus sparing drill hole canthoplasty

Table 28.1

Indications for surgery

Lateral canthal rounding/loss of almond-shaped eye

Lateral canthal dystopia

Shortened horizontal palpebral aperture, dynamic phimosis

Lateral canthal surgery in conjunction with lower eyelid retraction repair

Lateral canthal disinsertion

Table 28.2

Preoperative evaluation

History of prior surgery

Shape and location of lateral canthus

Horizontal and vertical palpebral aperture size

Presence of associated eyelid malposition, i.e. lower eyelid retraction, ectropion, lagophthalmos

Sufficiency of anterior lamella

Middle lamellar scarring

Symptomatic dry eye, foreign body sensation, epiphora

Introduction

Lower eyelid retraction, lateral canthal rounding, and inferior canthal dystopia are stigmata of unfavorable aesthetic eyelid surgery. Multiple factors contribute to these sequelae including exuberant resection of anterior lamellae, middle lamellar scarring, failure to treat lower eyelid laxity, and surgical misalignment of the canthus. Patients may present with symptomatic complaints of foreign body sensation, epiphora, and dry eyes. With complete disinsertion of the lateral canthal ligament from its bony attachment, dynamic phimosis may occur as the lateral canthal angle approaches the corneoscleral limbus with each blink. Combined lateral canthal dystopia and lower eyelid retraction following cosmetic blepharoplasty presents a special challenge to the oculofacial surgeon.

Many techniques have been described to correct canthal disinsertion and rounding in an effort to restore the almond-shaped eye. For mild cases, a canthopexy alone may be sufficient. In severe cases, however, suture fixation alone may be inadequate due to strong cicatricial contractile forces. Rigid fixation through the use of a bone tunnel provides the strongest attachment and more accurately replicates the native attachment of the lateral canthal tendon to Whitnall’s tubercle.

For drill hole fixation of the canthus, several options exist. The surgeon may make use of either one or two bone tunnels, depending on the desired effect. A single drill hole can be used to pass a single armed suture ( Figure 28.1A ). This attachment, while firm, may bring the canthal complex slightly anteriorly. A second option for use of a single drill hole is to use the bone tunnel as a fulcrum and fixation point to bring the canthus posteriorly in combination with midfacial elevation and orbitomalar suspension anteriorly ( Figure 28.1B ). This technique has the advantage of simultaneously fixating the canthus and recruiting anterior lamella with a single fixation point, joining the two sutures just external to the bone tunnel. Finally, if two bone tunnels are made, a double-armed suture is used, bringing the canthus posteriorly and passing each of the sutures through a separate tunnel and joining the two ends externally along the lateral orbital rim ( Figure 28.1C ). This technique is useful if posterior canthal fixation is solely desired. In cases of middle lamellar scarring and eyelid retraction, the drill hole canthoplasty can be combined with posterior lamella spacer grafts to also correct lid retraction ( Chapters 34 , 35 and 36 ). Skin grafts can also be used in cases of severe anterior lamellar deficiency, but in our experience, this is rarely necessary and while functional, does not lend well to aesthetic improvement ( Chapter 27 ).

A sharp lateral canthal angle provides an aesthetically pleasing appearance to the eyelid shape. Anatomical reattachment of the eyelid via lateral canthal fixation to a bone tunnel can also precisely control the vertical position of the canthus and preserve eyelid function. In our experience, fixation of the lateral canthus through a bone tunnel provides the strongest and longest lasting attachment.