Eyelid margin

The eyelid margin is an anatomic structure that we take for granted until we have to repair it. To repair a lid margin defect, you must know the eyelid margin architecture. We have discussed this in detail, but refer to Figure 12-1 to refresh your memory. Recall that the eyelid margin is a flat platform with nearly right angles at the anterior and posterior edges of the eyelid. From posterior to anterior, the anatomic structures that you should know are:

Figure 12-1 The eyelid margin architecture. Landmarks are the mucocutaneous junction, the meibomian gland orifices, the gray line, and the eyelashes. Note that the lid margin can be split into anterior and posterior lamellae, a concept helpful for lid reconstruction.

Precise alignment of the lid margin structures is necessary to repair eyelid margin defects. Tension-bearing sutures should be placed in the tarsal plate. Precise alignment of the lid margin using everting vertical mattress sutures is required to prevent a postoperative lid notch.

Anterior and posterior lamellae

You will recall that the anterior lamella of the eyelid consists of the skin and muscle. The posterior lamella of the eyelid consists of the conjunctiva and tarsal plate. Start to think of eyelid defects in terms of these anatomic building blocks.

In many patients, you can repair posterior lamellar defects by pulling the tarsal plate together as described above. For larger defects, you will need a graft to replace the tarsal plate. The best replacement for missing tarsus is other tarsal tissue either as a free tarsal graft from the contralateral upper lid or as part of a vascularized tarsoconjunctival flap from the upper lid on the same side (as you will see in the Hughes procedure for reconstruction of large lower lid defects). Other substitutes for the tarsal plate are the hard palate mucosa and, rarely, nasal cartilage.

Anterior lamellar defects are repaired with free skin grafts or myocutaneous advancement flaps. You cannot place an anterior lamellar free graft on a posterior lamellar free graft. There must be a vascular bed covering one surface of a graft. You can use a free tarsal graft for posterior lamella covered with a myocutaneous flap for anterior lamella. You can use the reverse, a free skin graft for anterior lamella over a tarsoconjunctival flap for the posterior lamella. Remember, don’t use a free graft on a free graft.

Lateral canthus

The lateral canthus is relatively simple anatomically. The upper and lower crus of the lateral canthal tendon extend from each tarsal plate to form the lateral canthal tendon. The lateral canthal tendon inserts at Whitnall’s tubercle on the inner aspect of the lateral orbital rim approximately 10 mm below the frontozygomatic suture (Figure 12-2). Although the lateral portion of the eyelid is attached to the rim mainly by the lateral canthal tendon, contributions from the orbicularis, orbital septum, levator aponeurosis, and lower lid retractors provide additional support for the eyelids.

Figure 12-2 (A) Canthal tendons. (B) The lateral canthal tendon attaches on the inner surface of the lateral rim. (C) The medial canthal tendon surrounds the lacrimal sac.

Think of the lateral canthal tendon as a Y. A cantholysis converts the Y of the lateral canthal tendon into a V. To release the lateral aspect of the lid, you must cut the respective crus of the lateral canthal tendon. Think of this as now cutting one leg of the V off the orbital rim (see Figure 13-15). Often you must make some additional cuts when performing the cantholysis to mobilize the lid. These cuts release the septum, orbicularis, and lower lid retractors, the other contributions to the lateral canthus that we just mentioned. You learned to do this when you performed a lateral tarsal strip procedure.

Reconstructing a lateral canthus is simple, anatomically. Remember to reattach the reconstructed tissues on the inside of the lateral orbital rim so that the eyelid margin rests against the curve of the eye. Usually you can reattach the lateral canthus to the periosteum of the bone. If there is no periosteum present, you may have to make small drill holes in the lateral orbital rim to attach the lid.

Medial canthus

The medial canthal tendon is anatomically more complex than the lateral canthal tendon. The anterior and posterior limbs of the medial canthal tendon surround the lacrimal sac (see Figure 12-2). The anterior limb of the medial canthal tendon attaches to the frontal process of the maxilla. The posterior limb of the medial canthal tendon attaches on the posterior lacrimal crest. A tough layer of tissue known as the lacrimal fascia surrounds the sac, fusing with the periosteum of the orbital rim and periorbita of the orbital walls. Disinsertion of the anterior limb of the medial canthal tendon will not change the position of the lower eyelid. An intact posterior limb of the medial canthal tendon will support the canthus and is required to pull the medial aspect of the eyelid posteriorly to follow the curve of the eye.

Attempts to reform the posterior limb of the medial canthal tendon are complicated by the lacrimal sac and canaliculus. If the lacrimal drainage apparatus is intact, it is difficult to provide a posterior point of attachment for a new medial canthus. If the canaliculus has been excised, you can recreate the pull of the posterior limb of the medial canthal tendon using permanent sutures to attach the medial end of any remaining lid to the posterior lacrimal crest.

Description of the postexcision defect

Learn to use these fundamentals of eyelid anatomy to describe the postexcision defect. Consider these examples:

Each description should bring to mind a picture of the anatomic structures involved and, eventually, the steps you will need to take to reconstruct the eyelid.

Biopsy techniques

If you suspect an eyelid malignancy, you already know to perform an incisional biopsy to confirm your diagnosis. The techniques of incisional biopsy were discussed in Chapter 11.

Tumor excision

Frozen section control

The majority of eyelid malignancies are treated by excisional biopsy. All surgical margins should be confirmed histologically to be free of tumor. Frozen section analysis of the margins is usually done before reconstruction. Alternatively, analysis of permanent sections for tumor-free surgical margins may be performed after reconstruction. However, if a margin is found to contain tumor, the reconstruction must be taken down and the excision repeated until tumor-free margins are obtained.

Ideally, your first several excisions for cutaneous malignancies should be performed on well-demarcated small nodular basal cell carcinomas. Outline the area of clinical involvement with the surgical marker. Draw a second ring around the tumor, marking an additional 3 mm of clinically uninvolved skin to be removed. Excise the tumor using the most peripheral marking. Orient the tissue for the pathologist with a suture. If frozen sections show residual tumor, re-excise the area of involvement. When the surgical margins are tumor free, you can reconstruct the eyelid. Often, surgeons will begin reconstruction while the frozen sections are being processed and analyzed. If you need a refresher on the excision technique, refer back to Figure 11-36.

As you gain experience, you may choose to excise larger nodular basal cell carcinomas. As your ability to perform larger, more complicated reconstructions improves, you can excise morpheaform basal cell carcinomas or squamous cell carcinomas (Figure 12-3). Remember that the margins of these more aggressive tumors are indistinct. The postexcision defect can be large in many patients.

Figure 12-3 Indistinct margins of recurrent squamous cell carcinoma in an elderly man. You can imagine that a postexcision defect will be large.

Radiotherapy

Radiotherapy has been used extensively in Canada for the treatment of periocular malignancies. The cure rate is said to be high. Skin malignancies are relatively radioresistant so high doses of radiation therapy are required. An obvious advantage is that no reconstruction is required. Disadvantages include no histologic confirmation of complete tumor removal and the side-effects related to radiotherapy. In the United States, the majority of cutaneous malignancies are surgically excised. Radiotherapy is reserved for large recurrent tumors and is often considered palliative in these patients.

Cryotherapy

Cryotherapy, using liquid nitrogen, is used for precancerous actinic keratoses. Small nodular basal cell carcinomas away from the eyelids can also be treated with liquid nitrogen. Long-term follow-up is required to ensure that there is no recurrence.

Options for repair

We have used the terms anterior and posterior lamella to describe the layers of the eyelid near the lid margin. In this chapter, we will use the term anterior lamella to also describe skin and muscle defects peripheral to the tarsal plates where no true posterior lamella exists. There are several options for repair of skin and muscle defects in the periocular area:

We will talk about the advantages and disadvantages of each technique. For many defects, more than one technique may work. You will learn to choose the best technique for the particular defect. Small lesions away from important landmarks will heal by granulation over time. Although successful in some patients, the healing may take weeks to months. Scar contracture can result in distortion of anatomic landmarks. Primary closure with or without undermining is generally a better option. Myocutaneous advancement flaps are the best choice for larger anterior lamellar defects. Free skin grafts give the least acceptable result, but allow you to cover any size anterior lamellar defect. If you cannot perform a more aesthetically acceptable procedure, you can always use a skin graft, so it is important to learn the technique.

Primary closure

Primary closure can be performed if redundant skin exists adjacent to the defect. Areas of the face that typically have redundant skin include the glabella, the upper lid skin fold, and the temple. There is normally little redundant skin in the lower eyelid or medial canthus. You will also learn to appreciate how the amount of redundant tissue varies from one patient to the next. The patient with wrinkled and sagging skin has plenty of redundancy to help you close small defects. In the patient with sun-damaged, tight skin with no wrinkles despite advancing age, more than primary closure will be required for all but the smallest defects (Figure 12-4).

Figure 12-4 Middle-aged man, an outdoor worker, with sun-damaged tight skin. Despite the small size of the defect, extensive undermining was required to pull the stiff, inelastic skin closed.

Primary closure with undermining

Primary closure with undermining is commonly used to close lesions away from the eyelid margin. You must know the level to undermine to mobilize tissue, preserve blood supply, and avoid nerve damage (Box 12-1). Within the orbital rims, any tissue undermining should be done in the preseptal plane. Outside the orbital rims, undermining should be done in the subcutaneous tissue plane. Be especially careful when undermining any tissue in the path of the seventh nerve extending from the tragus of the ear to the tail of the eyebrow. The facial nerve is superficial as it crosses over the zygomatic arch. When closing areas in the forehead or scalp, you should undermine deep to the frontalis muscle in the loose areolar tissue superficial to the periosteum. You will find that extensive undermining is usually necessary to mobilize skin in the scalp or forehead (Figure 12-5).

Figure 12-5 Dissect in the appropriate tissue plane for developing facial flaps. (A) Eyelid—under the orbicularis muscle (preseptal plane). (B) Cheek—within the subcutaneous tissue. (C) Forehead and scalp—in the loose areolar tissue plane anterior to the periosteum and posterior to the galea or frontalis. For large defects, relaxing incisions may be required in the galea.

When closing a wound, always orient the closure to minimize tissue distortion and maximize scar camouflage. Closing a forehead wound parallel to the forehead furrows creates less tissue distortion and a better scar than a vertical closure can provide. Depending on the size of the defect, the eyebrow may be elevated. Remember that tissue is most easily mobilized in a direction 90 degrees from the natural skin creases.

When reconstructing the lower lid, minimize any vertical traction on the eyelid by closing wounds to leave a vertical scar. Although the vertical scar does not blend in with the natural skin creases, this technique will avoid ectropion or lid retraction (Figure 12-6).

Figure 12-6 Plan the reconstruction to minimize horizontal tension on the lower eyelid to prevent lower lid ectropion or retraction. (A) Defect after excision of basal cell carcinoma in a young patient with no redundant tissue. (B) Undermining laterally and medially allowed closure without creating vertical tension, avoiding lid retraction or ectropion.

Do enough undermining to minimize tension on the skin closure. Use deep anchoring sutures to the underlying periosteum to support the deep tissues and take tension off the subcutaneous and skin closure. Common places to use anchoring sutures are at the periosteum along the inferior and lateral orbital rim. When using anchoring sutures to prevent lower eyelid retraction or ectropion, place the sutures superiorly to overcorrect the lower eyelid or canthal height.

When the tension is off the edges of the wound, use an interrupted deep layer closure with an absorbable suture such as 3-0 PDS in the scalp, 4-0 PDS in the cheek, and 5-0 PDS in the orbicularis muscle. Perform a routine skin closure with slight eversion of the wound edges. Interrupted sutures provide the best wound alignment and eversion. Running sutures can be used when you anticipate that the scar will fall within a natural skin crease.

Free skin grafts

Free skin grafts are harvested from a donor site and transferred to fill an anterior lamellar defect. The vascular supply to the free graft must be provided by the recipient site for the graft to “take” or survive. You will use full-thickness skin grafts routinely in reconstructive eyelid surgery.

Full-thickness skin graft

The term full-thickness skin graft (FTSG) means that an entire thickness of the epidermis and dermis has been removed for transfer. The floor of the donor site is usually subcutaneous fat. The donor site must be closed surgically, which limits the size of the graft available for transfer. All the skin appendages are contained within the donor skin, so you should choose a hairless donor site for obtaining the graft. FTSGs heal with less shrinkage than split-thickness skin grafts, making the full-thickness technique better suited for eyelid reconstruction where shrinkage can cause ectropion, lid retraction, or lagophthalmos.

Donor sites include (Figure 12-7):

• Upper eyelid skin

• Retroauricular skin

• Preauricular skin

• Supraclavicular or upper inner arm skin

Figure 12-7 Donor sites for full-thickness skin grafting. In order of preference: upper eyelid, preauricular, retroauricular, supraclavicular, and upper arm.

When possible, donor skin of the same color, texture, and thickness should be picked for transfer. Upper eyelid skin is the best choice for reconstructing eyelid defects. From a practical point of view, this skin is seldom used for fear of creating upper eyelid skin fold asymmetry or lagophthalmos. When the situation permits, grafts can be taken from both upper eyelids to obtain sufficient skin and maintain symmetry. The results of full-thickness skin grafting with upper eyelid skin are good (refer back to Figure 3-11).

The traditional donor site is retroauricular skin. However, it is difficult to work behind the ear and somewhat uncomfortable for patients postoperatively. Preauricular skin is similar to retroauricular skin in character and is much easier to harvest. Slightly less skin is available, but the 15 mm by 40 mm area from the preauricular site is well suited in size and shape for most eyelid grafting. We discussed the technique of preauricular skin grafting in Chapter 3, so I’ll review it only briefly here.

Inject local anesthetic containing epinephrine into the preauricular area. Transfer a template of the defect to the preauricular region. Outline the template on the skin. Incise the skin with a blade or Colorado needle, and create a plane of dissection between the subcutaneous fat and the skin. After removing the skin graft, trim any fat off the graft before suturing it into the defect. Use a running suture to sew the graft into place. Sew a bolster over the graft, and patch the eye for 1 week. Close the preauricular site with subcutaneous interrupted 4-0 PDS sutures and a cutaneous 5-0 Prolene running suture.

Graft survival is usually high when the FTSG is placed on a healthy bed of tissue. The graft will often look dark at 1 week. Normal color and texture will return several weeks postoperatively. A small amount of shrinkage of the graft is expected (Figure 12-8). FTSGs do not take well on bare bone.

Figure 12-8 Full-thickness skin graft for repair of an anterior lamellar defect of the upper eyelid and brow. (A) Defect after excision of a basal cell carcinoma. (B) Full-thickness skin graft in place. Dark color is often present and does not suggest poor survival. Note that the full-thickness skin has been harvested from bilateral upper blepharoplasties. (C) Result 1 year postoperatively.

Split-thickness skin graft

You should know about split-thickness skin grafts, although you will seldom use them in eyelid reconstruction. A split-thickness skin graft (STSG) is harvested by leaving the deep layer of the dermis intact. The normal donor site is the thigh. Typically, a power dermatome is set to harvest a layer of skin between 0.012 and 0.020 inch thick from the thigh. The donor site will epithelialize spontaneously over a few weeks. Because the skin appendages are left in the donor site, you can harvest a STSG from hair-bearing skin.

The main advantage of a STSG is that a large area of skin may be harvested because no skin closure is required. Split-thickness skin will usually survive on bare bone, especially if the cortical bone is burred to create some bleeding. The donor skin is thin, and considerable shrinkage is always seen (Figure 12-9). The color, texture, and thickness are often a poor match for eyelid skin. As you might guess from this description, STSGs are used only if the defect is too large for a FTSG and there is no myocutaneous flap that is practical for closure.

Figure 12-9 Split-thickness skin grafting. (A) Preoperative large anterior lamellar defect. (B) Split-thickness skin graft in place. (C) One year postoperatively, note shrinkage and poor color match of the graft. Note that the lower eyelid was tightened at the time of grafting to help prevent cicatricial lid retraction.

Myocutaneous flaps

Advancement of a myocutaneous flap is usually the best choice to repair an anterior lamellar eyelid defect. Use these flaps whenever possible. Myocutaneous flaps in the periocular area are formed of skin and orbicularis muscle that is dissected off the underlying orbital septum and stretched into position over the anterior lamellar defect. Myocutaneous flaps have many advantages over free skin grafts:

Related posts:

The Diagnosis and Management of Misdirected Eyelashes The Art of the Surgical Technique Aesthetic Surgery of the Face Evaluation and Treatment of the Patient with Ptosis Diagnosis of Malignant and Benign Lid Lesions Made Easy The Diagnostic Approach to the Patient with Proptosis

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