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 ).








Figures 28.1A–C


Different methods of lateral canthal tendon fixation

A single drill hole lateral canthoplasty can be used to anchor the lateral canthal tendon ( Figure 28.1A ). This method provides a firm basis for lateral canthal fixation but does not provide deep posterior migration of the canthal complex. Figure 28.1B shows a single drill hole canthoplasty combined with elevation of the suborbicularis oculi fat (SOOF). This method provides rigid lateral canthal support as well as midfacial recruitment to support a retracted lower eyelid. Double drill hole canthoplasty provides robust fixation of the lateral canthal complex and strong posterior displacement of the entire canthus ( Figure 28.1C ).


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.




Surgical Technique





Figures 28.2A and 28.2B


Lateral canthus sparing incision

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May 16, 2019 | Posted by in Reconstructive surgery | Comments Off on Canthus sparing drill hole canthoplasty
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