Eyelids/periorbital

The eyelids are composed of cutaneous skin (<1 mm thick), orbicularis oculi muscle, the tarsal plate, and the conjunctiva. At the eyelid margin the skin tightly adheres to the tarsal plate. In the vertical dimension the inferior tarsal plate is 3 to 5 mm tall and the superior tarsal plate is 10 to 12 mm high. The tarsal plates connect to the bony orbital rim by the medial and lateral canthal ligaments. These ligaments can be cut intentionally for more laxity if needed (eg, for a large wedge repair), or sutured to different areas of the orbital rim to perform a canthopexy. The lacrimal gland with its canaliculi sits in the superior and lateral area of the upper eyelid, and the lacrimal caruncle, canaliculi, and sac are located in the medial/inferior canthus area. If these features are inadvertently damaged during surgery they can cause dry or watery eyes, respectively.

Specialized tools used for MMS on the eyelids include, but are not limited to, corneal shields (we favor plastic shields over the metal ones used for laser to eliminate the risk of inadvertent damage to the cornea and sclera during electrocoagulation), chalazion clamps, small curved iris scissors, Castroviejo scissors and needle holder, Bishop-Harmon forceps, Stevens tenotomy or gradle scissors, micro/beaver blades, 15-c scalpel blades, and micro-tipped/fine-tipped, Teflon-coated, electrosurgery tips.

Approximately 5% to 10% of skin cancers occur in the periocular region ( Table 1 ). Risk factors for periocular neoplasms include advancing age, fair skin, family history, and chronic sun exposure. The most common malignancies are BCC (90%), sebaceous carcinoma (5%), SCC (4%), followed by malignant melanoma (1%), lymphoma, Kaposi sarcoma, MAC, and rarely Merkel cell carcinoma ( Box 1 ). BCCs (∼70% of the time), SCCs (∼68%), and melanoma (∼57%) occur more commonly on the lower lid. On the other hand, sebaceous carcinoma occurs on the upper eyelid 63% of the time because the upper eyelid has more sebaceous glands than the lower lid. Most BCCs and SCCs involve the lower eyelid, followed by the medial canthus or upper eyelid and then lateral canthus. Eyelid BCCs, SCCs, sebaceous carcinoma, and Merkel cell carcinoma have all been treated with traditional frozen section MMS, and malignant melanoma has been treated with modified slow Mohs with paraffin-embedded tissue, all with lower recurrence rates versus surgical excision ( Table 2 ).

Adverse outcomes that may occur whenever surgery is attempted on the eyelids include the normal complications seen in any skin surgery repair such as scarring, dehiscence, flap failure or graft necrosis, hematoma, and infection. Site-specific complications may include ectropion, trichiasis, lagophthalmos, ptosis, keratoconjunctivitis, sicca, watery eye, webbing, entropion, and orbital hemorrhage.

Repair options for Mohs defects on the eyelids or periocular skin include, but are not limited to, secondary intention healing, direct closure, grafting, pentagonal excision with direct closure, lateral canthotomy and inferior cantholysis with direct closure, Tenzel semicircular advancement flap, Mustardé laterally based cheek rotation flap, Hughes tarsoconjunctival flap, hinge flap with or without cheek advancement flap, Cutler-Beard bridge flap, glabellar flap, forehead flap, and the spiral flap.

It is important to consult or refer to oculoplastic colleagues when a repair is beyond the skill or expertise of the Mohs surgeon. If the Mohs surgeon is comfortable performing the repair, it is important to pay close attention to suturing technique, placing any sutures or knots on the cutaneous side of the eyelid, including throwing the deep sutures with the knots facing outward and away from the cornea so as to not cause abrasion and resultant scar. This technique is counter to the typical dermal buried suture technique. Here, suture is passed through the wound edge superficial to deep and deep to superficial so that the knot is more superficial and not buried toward the cornea. It is also important to close the muscle layer and cutaneous layers, paying attention to tarsal plate alignment. The mucosal side can be closed via a buried or subcuticular suture; however, if the muscle and cutaneous eyelid are well approximated, the mucosal eyelid often heals nicely by secondary intent. If necessary, a Frost suture (a horizontal mattress through the lower lid taped to the superior brow) may be used to reduce downward traction and possible cicatricial ectropion. Proper eye patches when needed and good postoperative wound care instructions for the patient can help put the patient at ease and alleviate their fear before leaving the office.