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If your incisional biopsy of a cutaneous tumor shows malignancy, the next step is excision with documentation of tumor-free surgical margins. Reconstruction follows tumor excision. Unusual malignant eyelid tumors may be controlled with cryotherapy, chemotherapy, or radiation treatments, but surgical excision is the most common technique.
Reconstruction is based upon the surgical principles with which you are already familiar. The goal of the reconstruction is to restore the normal anatomy and function. You may be impressed by how quickly you can learn successful eyelid reconstruction techniques. You find that reconstructions are a fun part of your surgical day. Each is different. Initially the idea of being able to fill any defect that comes to you is a bit daunting. As your skill set increases, the options open to you become unlimited.
We begin this chapter with a review of the eyelid and periocular anatomy that is especially important for understanding the concepts involved with lid reconstruction. Use these fundamentals of eyelid anatomy to describe the postoperative excision defect and to plan the reconstruction.
Your choice of reconstructive technique depends on what portions of the eyelid are missing. Smaller anterior lamellar defects can be closed primarily or with some undermining . Larger defects require a myocutaneous advancement flap or free skin graft. Skin grafts are usually full-thickness grafts to avoid shrinkage. Very large defects away from the lid margin occasionally require repair with a split-thickness graft. The preferred technique for repair of larger anterior lamellar defects is a myocutaneous advancement flap . These advancement flaps have several advantages over free skin grafts. We describe the basic techniques for skin grafting and forming myocutaneous advancement flaps in this chapter.
Full-thickness eyelid defects of up to 25% of the eyelid margin can be repaired by pulling the eyelid margins together and suturing them using a primary eyelid margin repair technique. This is the same technique that you use to repair many traumatic lacerations of the eyelid margin. Small lid margin defects involving the lateral canthus are repaired using a simple lateral canthoplasty technique, such as the lateral tarsal strip operation. Medial eyelid margin defects are more difficult to repair because of the presence of the lacrimal drainage system.
If you find that pulling the edges of the full-thickness eyelid wounds together creates a great deal of tension, you need to perform canthotomy and cantholysis to allow the lateral portion of the lid to slide over. Larger full-thickness lid defects require special techniques for closure. Using the Tenzel flap or Hughes procedure , you are able to repair lid margin defects involving 50% and 100% of the lower eyelid. If you are interested in having an active practice in skin cancer removal and eyelid reconstruction, you should learn all of the techniques that we have discussed thus far. With some experience, you learn to modify these procedures and use them in combination. More advanced procedures such as the Mustarde cheek rotation and median forehead flap are used to cover large anterior lamellar defects.
Small upper eyelid defects can be closed using the same principles as those for lower eyelid reconstruction. When more than 50% of the upper lid is missing, more complicated operations are required. The Cutler–Beard procedure is the traditional operation for repairing large upper eyelid defects. This operation borrows tissue from the lower lid to re-create the upper lid. It is complicated, and I rarely use it. Our current technique uses a combination of free grafts and flaps, which are explained later. This technique was something that I taught myself based on principles that you will learn. It is now in common practice in our specialty, I believe. Eyelid reconstruction is a good learning experience and sometimes a challenge. Large upper eyelid reconstructions are the most difficult reconstructions. You won’t want to tackle these until you can confidently perform the basic procedures.
In this chapter, I describe the operations that an interested and well-trained surgeon should use in repairing eyelid defects and give enough detail that you can perform them. I describe the more advanced procedures with less detail but give enough that you can learn the concepts.
Fundamentals of Eyelid Anatomy
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:
The mucocutaneous junction
The meibomian gland orifices
The gray line
The eyelash follicles
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
The anterior lamella of the eyelid consists of 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 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 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 the posterior lamella covered with a myocutaneous flap for the anterior lamella. You can use the reverse, a free skin graft for the anterior lamella over a tarsoconjunctival flap for the posterior lamella. Remember, don’t use a free graft on a free graft.
The concept of anterior and posterior lamellae, in the strictest sense, applies only to the tarsal portion of the eyelids. The concept is extended to the periocular area, however. Here, we describe defects just involving the skin and muscle as anterior lamellar defects. As an aside, you may hear the term middle lamella used. To me, the middle lamella involves the eyelid tissues peripheral to the tarsus, extending posterior to the orbicularis muscle and anterior to the conjunctiva (i.e., the septum, fat, and eyelid retractors). Middle lamellar scarring is a common cause of lower eyelid retraction and, occasionally, upper eyelid lagophthalmos.
The lateral canthus is relatively simple anatomically. The upper and lower crura 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 muscle, orbital septum, levator aponeurosis, and lower lid retractors provide additional support for the eyelids.
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 13.17 in Chapter 13 ). Often you must make some additional cuts when performing the cantholysis to mobilize the lid. These cuts release the septum, orbicularis muscle, 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 in terms of anatomy. 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. You can reattach tissue to any remaining bit of the opposite crus of the lateral canthal tendon if present. As a lesser choice, you can reattach the eyelid to tissue outside the rim, but that does not allow the lid to lay tight against the eye at the lateral 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 does not change the position of the eyelids. An intact posterior limb of the medial canthal tendon supports the canthus and is required to pull the medial aspect of the eyelid posteriorly to follow the curve of the eye.
Attempts to re-form 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 re-create 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 Postoperative Excision Defect
Learn to use these fundamentals of eyelid anatomy to describe the postoperative excision defect. Consider these examples:
Full-thickness defect of the central 25% of the lower eyelid
Full-thickness defect of the lower eyelid involving the lateral 50% of the eyelid, including the lateral canthal tendon
Anterior lamellar defect over the inferior orbital rim measuring 1 cm by 1.5 cm
Full-thickness defect of the upper eyelid involving the medial one third of the lid, including the punctum and canaliculus
Each description should bring to mind a picture of the anatomic structures involved and, eventually, the steps needed to reconstruct the eyelid.
Treatment of Malignant Cutaneous Tumors
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 .
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 experiences excising cutaneous malignancies should be performed on well-demarcated small nodular basal cell carcinomas. You are more likely to excise the tumor without several attempts to identify any hidden microscopic extensions. 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 begin reconstruction while the frozen sections are being processed and analyzed. If you need a refresher on the excision technique, refer back to Figure 11.59 in Chapter 11 .
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 postoperative excision defect can be large in many patients.
If you plan to treat a large number of cutaneous malignancies, you should develop a good working relationship with a surgeon trained in Mohs excision. Mohs excision of cutaneous malignancies provides a high cure rate with the minimum amount of excision of normal tissue along with the tumor. The Mohs surgeon, usually a dermatologist, performs both the excision and the microscopic interpretation of the tissue. The expertise of a Mohs surgeon can benefit you and your patient. The Mohs surgeon returns the patient to you with the malignancy excised, ready for your reconstruction. Mohs surgery is especially useful for large nodular basal cell carcinomas, morpheaform basal cell carcinomas, squamous cell carcinomas, and any recurrent tumor. The role of Mohs excision in the treatment of sebaceous cell carcinoma and cutaneous melanoma is controversial because the surgical margins of these tumor excisions are difficult to interpret using frozen-section analysis. You should discuss sebaceous cell and melanoma excision with your Mohs colleague before sending these patients to them.
Radiotherapy has been used extensively in Canada for the treatment of periocular malignancies in the past. 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.
We discussed the role of vismodegib for the treatment of advanced basal cell carcinoma in the last chapter. More than 90% of basal cell carcinomas have a mutation that causes activation of the hedgehog pathway, which is crucial for embryonic development but normally has limited activity in adult tissues. Vismodegib is an oral medication that specifically blocks the hedgehog pathway, inhibiting the growth of these cancers. The effect of treatment dissipates if the medication is stopped, however. There are many side effects of the treatment that can limit its use; nonetheless, it can be an alternative to exenteration or other radical excisions (refer back to Figure 11.5 in Chapter 11 ). This medication is now being considered as an adjuvant therapy for less advanced basal cell tumors. It is possible that vismodegib could be used to shrink a large tumor and allow for a smaller resection. This technique is considered experimental at this point and is not in general use. Vismodegib has no effect on squamous cell carcinoma, melanoma, or sebaceous cell carcinoma.
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.
At this point, you should know the fundamentals of eyelid anatomy that guide reconstruction. As you read the text, try to visualize the defects that are discussed and describe them anatomically.
We have briefly discussed the steps of incisional biopsy and tumor excision with frozen-section–controlled margins or Mohs surgery, and you are ready to learn lid reconstruction techniques.
Anterior Lamellar Defects
Options for Repair
We have used the terms anterior lamella and posterior lamella to describe the layers of the eyelid near the lid margin. In this chapter, we 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:
Healing by granulation
Primary closure with undermining
Free skin graft
Myocutaneous advancement flap
We talk about the advantages and disadvantages of each technique. For many defects, more than one technique may work. Learn to choose the best technique for the particular defect. Small lesions away from important landmarks 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 of anterior lamellar defect. If you cannot perform a more esthetically acceptable procedure, you can always use a skin graft, so it is important to learn the technique.
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, upper lid skin fold, and temple. There is normally little redundant skin in the lower eyelid or medial canthus. 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 is required for all but the smallest defects ( Figure 12.4 ).
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 which to undermine in order to mobilize tissue, preserve the 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. Extensive undermining is usually necessary to mobilize skin in the scalp or forehead ( Figure 12.5 ).
When doing any soft tissue surgery think in terms of tissue planes:
Know the tissue planes well.
What plane do you need to be in?
What plane are you in?
Common tissue planes to work in are:
Eyelids: preseptal plane
Cheek skin: subcutaneous plane
Forehead: subcutaneous plane, subgaleal plane (posterior to the frontalis muscle)
Temple: posterior to temporal parietal fascia along superficial layer of deep temporalis fascia
Avoid danger areas for the facial nerve:
Overlying the zygomatic arch (where the nerve is the most superficial)
1 cm lateral to the tail of the brow (where the temporal branch runs)
Most dissections in the temple are performed deep to the facial nerve in the plane superficial to the deep layer of the temporalis fascia. This plane allows you to move the temporal parietal fascia (remember, it’s the SMAS equivalent in the temple, like the galea in the forehead). You often have to cut the conjoined tendon and enter the subgaleal plane (preperiosteal plane) of the forehead to get effective movement of tissues. These are the same dissection planes that we use in the endobrowplasty and transblepharoplasty operations. In some cases, you can create a dissection plane in the subcutaneous layer, anterior to the facial nerve. In general, this more superficial plane works for only smaller defects in the subcutaneous layer, anterior to the facial nerve.
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 avoids ectropion or lid retraction ( Figure 12.6 ).
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 use full-thickness skin grafts routinely in reconstructive eyelid surgery.
Full-Thickness Skin Graft
The term full-thickness skin graft 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. Full-thickness skin grafts 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
Supraclavicular or upper inner arm skin
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 3.13 in Chapter 3 ).
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 (maybe slightly thicker, but a better skin color match) 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 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. In lower eyelid cases, a lid-tightening procedure such as a lateral tarsal strip operation is appropriate if laxity exists. After removing the skin graft, trim any fat off the posterior graft surface before suturing it into the defect. Use a few interrupted cardinal sutures followed by a running suture to sew the graft into place. Sew a bolster over the graft (or place a wad of Xeroform gauze) 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. In recent years, I have added postoperative oral cephalosporin while the patch is in place, but this may not be necessary.
In rare cases where patching is not practical (the one-eyed patient), I have used quilting sutures to hold the graft in place and then sutured on a bolster. I know of surgeons that place tissue glue on the graft site to hold the graft into position. I use TISSEEL or Evicel commonly for mucous membrane grafts but not routinely for skin grafts. For lower eyelid skin grafting cases, I often use a Frost suture taped to the forehead to stabilize the eyelid in an elevated position.
Graft survival rates are usually high when the full-thickness skin graft is placed on a healthy bed of tissue. The graft often looks dark after 1 week. Normal color and texture return several weeks postoperatively ( Figures 12.8 and 12.9 ). A small amount of shrinkage of the graft is expected (see Figure 12.8 ). If the recipient site seems too avascular for a graft, you may choose to wait several days while a layer of granulation tissue grows in the wound. This is especially helpful on the nose, where the vascular supply may be very poor. Full-thickness skin grafts do not take well on bare bone.
Split-Thickness Skin Graft
You should know about split-thickness skin grafts, although you seldom use them in eyelid reconstruction. A split-thickness skin graft 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 epithelializes spontaneously over a few weeks. Because the skin appendages are left in the donor site, you can harvest a split-thickness skin graft from hair-bearing skin.
The main advantage of a split-thickness skin graft is that a large area of skin may be harvested because no skin closure is required at the donor site. Split-thickness skin usually survives 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 12.10 ). The color, texture, and thickness are often a poor match for eyelid skin. As you might guess from this description, split-thickness skin grafts are used only if the defect is too large for a full-thickness skin graft and there is no myocutaneous flap that is practical for closure.
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:
Locally available tissue
Good match for color and texture
Near normal innervation
Carries a blood supply to allow use over bare bone
High rate of successful healing
Locally available tissue means that little additional injecting, preparing, and draping are necessary to perform the surgery. Because the tissue is adjacent to the defect, the match for color and texture is good. After healing, near normal sensory and motor innervation returns to the mobilized tissue. Because the myocutaneous flap brings its own blood supply, bare bone or free grafts can be covered. Properly designed myocutaneous advancement flaps on the face rarely become infected or ischemic because the blood supply to the face is so rich. Often it is difficult to see the operative site after complete healing has occurred.
You have already been creating myocutaneous flaps as parts of other procedures. Surgical approaches to the inferior orbital rim for a transcutaneous lower blepharoplasty, fracture repair, and retractor reinsertion are all examples of myocutaneous flaps. You create an upper lid myocutaneous flap each time you perform an upper lid blepharoplasty or ptosis repair. Some specific tips help when creating myocutaneous flaps for reconstruction:
Choose natural skin creases to hide the incision lines.
Know the planes to move into when you advance peripheral to the orbital rims.
Create horizontal tension rather than vertical tension on the lower eyelid.
Develop the flap so that there is little tension on the final closure.
Use anchoring sutures to reduce tension on the skin and provide vertical support.
Always overcorrect the position of the flap.
Consider tightening the lower eyelid if you are concerned about retraction or you have shortened the anterior lamella.
Most skin cancers that you see occur on the lower eyelids. The most common incision for creating a myocutaneous flap is the subciliary incision, which you can extend laterally into a laugh line. As you develop the flap, continue the dissection until there is as little tension on the wound closure as possible. It takes some experience to know how far to undermine. When in doubt, do more dissection to free up the flap. Each patient’s tissues stretch different amounts, so there are no exact formulas for determining how far to extend the flap.
If you extend the flap beyond the orbital rims onto the cheek, stay posterior to the orbicularis muscle and enter the subcutaneous plane of the cheek. This is an important concept. Remember that when doing any soft tissue surgery, you must think in terms of tissue planes. Plan the operation based on tissue planes. Ask yourself, “What plane do I need to be in now?” During the operation, ask, “What plane am I in now?” Be especially careful in danger zones where damage to the facial nerve can occur. Keep your dissection superficial over the path of the facial nerve, from the tragus of the ear to the tail of the brow, especially over the zygomatic arch.
When you close a defect, construct the flap so that any tension on the lower eyelid is horizontal rather than vertical. A simple example is the 2-cm circular anterior lamellar defect in the lower eyelid shown in Figure 12.11 . The defect can be closed leaving a vertical scar or a horizontal scar. Although the horizontal scar is more natural, ectropion or lid retraction can be produced. The vertically placed scar puts horizontal traction on the eyelid, so the eyelid is not pulled inferiorly or away from the eye.
As you develop the flap, stop and pull the tissue into place to see if you have dissected enough to take the tension off the skin closure. When in doubt, dissect further. After you have freed up enough tissue, place one or more anchoring sutures from the undersurface of the flap to the periosteum at the orbital rims (or other deep tissue) to support the flap position and reduce the tension on the skin closure. Another good place to anchor is just posterior to the lateral orbital rim in the temporalis fascia. It is always wise to overcorrect the vertical height of the flap at the lateral canthus and along the lower lid margin. As the wound heals, some contracture occurs. Overcorrection by a small but noticeable amount prevents lid retraction and lateral canthal dystopia.
You may want to tighten the lower lid when you close the anterior lamella under horizontal tension. Sometimes the posterior lamella is too lax for the tight anterior lamella. In extreme cases, the posterior lamella bunches up posterior to the tight anterior lamella (the flap). If you think that this may be a problem, do a lateral tarsal strip operation at the time of anterior lamellar closure. I often tighten the lower eyelid with lid reconstruction. As you recall, a tight lower eyelid is a stable eyelid. It is less likely to become ectropic or retracted.
As you get experience, you may be able to bend the rules a bit. If the defect is small enough, you may be able to close it vertically, leaving a horizontal scar. To do this, you must create redundant tissue in a vertical orientation by undermining the cheek in the subcutaneous plane and lifting the tissue vertically. You need to use anchoring sutures to prevent the eyelid from being pulled down ( Figure 12.12 ). Place deep 3-0 or 4-0 PDS sutures from the cheek subcutaneous tissues to the lower rim of the periosteum to support the cheek, preventing any traction on the lower eyelid. You may want to put deep sutures from the flap to the lateral canthal periosteum or temporalis fascia. Remember to overcorrect the height of the flap. This technique of undermining and anchoring of the soft tissues is a functional midface lift. Although this technique is worthwhile to learn, it is somewhat advanced and requires some technical experience and judgment for you to be able to decide which patients might benefit from it (see the section on hatchet flaps in this chapter).
At this point, we have covered the options for anterior lamellar repair. You should always consider primary closure with or without undermining before you try the other options. These options are a free skin graft and a myocutaneous advancement flap.
What is the difference between full-thickness and split-thickness skin grafts? Which is more suitable for eyelid reconstruction? Which shrinks less? Name three possible donor sites for a full-thickness skin graft.
Which is the first choice for anterior lamella repair: full-thickness skin grafts or myocutaneous advancement flaps?
Name three advantages of a myocutaneous advancement flap over a full-thickness skin graft.
What is the dissection plane for: