Surface Anatomy

It is useful to conceptually divide the face into aesthetic units when discussing reconstructive techniques.^1,2 Recognizing the junction lines between neighboring units is important as they conceal surgical scars well. Most authors use the eyebrow as the superior limit of the periocular aesthetic unit; however, the suprabrow area can also be considered to be part of the periocular area, as closures in this area can affect the eyebrow and upper eyelid (Figure 12.1). The infraorbital and nasojugal creases define the inferior border of the periocular unit. The nasofacial sulcus marks the medial border in the medial canthal area, while the frontal process of the zygomatic bone defines the lateral margin. Anatomically, it is also useful to distinguish the palpebral portions of the upper and lower eyelids, which overlie the globe when the lids are closed, from the orbital portions, which continue over the bony orbital margin to the edge of the periocular aesthetic unit.

Figure 12.1 Surface anatomy of the periocular area.

Other naturally occurring skin folds and creases within aesthetic units can similarly be used to hide surgical scars, as these lines appear normal and do not attract attention. The upper eyelid crease, for example, hides upper blepharoplasty incisions. Other aspects of periocular aesthetics should also be considered when moving tissue for reconstruction. The concavity of the medial canthus, the symmetry of the eyelids, and the orientation of eyebrow hairs are some of the more subtle features that can become conspicuous if undesirably altered. Attention to these surface characteristics will help avoid distortion of periocular structures and promote aesthetically proper surgical closures.

Surgical Anatomy

A thorough knowledge of the anatomy of the periocular region is paramount to successful surgery in this area (Figure 12.2). Understanding tissue planes and functional relationships between anatomic structures serve the surgeon well in this complex area. Familiarity with the location of nerves, blood vessels, and “danger zones” is critical to achieving optimal surgical results and avoiding bad outcomes.

Figure 12.2 Surgical anatomy of the periocular area. Note the superficial location of the temporal branch of the facial nerve as it approaches the periocular area. It lies between the thin superficial muscular aponeurotic system (SMAS) layer and the temporalis fascia for most of its course here. Only as it crosses the edge of the frontal bone does it dive under the frontalis muscle and become more protected. Not pictured in this diagram are the superior and inferior palpebral arteries, which arch across the eyelids parallel to the lid margins, piercing the orbital septum above and below the medial and lateral canthal tendons.

The margins of the bony orbit are defined by the frontal bone superiorly, the zygomatic bone inferolaterally, and the maxilla inferomedially. Within the orbit sits the globe with its associated vessels, muscles, nerves, fat, and most of the lacrimal apparatus. The orbital septum, a membranous sheet of connective tissue that arises from the periosteum of the orbital rim and spans across the lids, separates the globe and deeper orbital structures from the more superficial muscles and skin. Within each eyelid is a crescent-shaped tarsal plate, the fibroblastic lamina that provides the semirigid structure of the lid. The medial and lateral ends of these plates are stabilized by the medial and lateral canthal tendons, respectively, which attach to the adjacent bony orbit.

The orbicularis oculi muscle lies superficial to the orbital septum. The sphincter muscle of the eyelids, it controls blinking and forceful eyelid closure. It can be divided into palpebral and orbital portions. The palpebral part, confined to the eyelids, arises from the medial canthal tendon and arches across both lids (anterior to the tarsal plates) to insert into the lateral canthal tendon. In oculoplastic surgery it is useful to further subdivide this part into the pretarsal and preseptal portions. The orbital portion of the muscle, located more peripherally, lies flat on the surface of the orbital margin, bordering the forehead and cheek. Its fibers arise from the medial end of the medial canthal tendon and adjoining bone to extend laterally in a series of uninterrupted concentric loops around the orbit. The elevator of the upper lid is the levator palpebrae superioris, a long, flat muscle above the globe. Its aponeurosis fuses with the orbital septum superiorly to insert into the superior tarsus and skin of the upper eyelid.

The upper eyelid is larger and more mobile than the lower eyelid, and it completely covers the cornea when the lids are closed. The skin of the eyelids is less than 1 mm thick with minimal subcutaneous tissue, and it is tightly adherent to the underlying muscle in the pretarsal region. Over the preseptal and orbital regions, the skin is more mobile. The posterior surface of the eyelids is lined by the palpebral conjunctiva, a thin mucous membrane that reflects in the superior and inferior fornices of the conjunctival sac onto the anterior surface of the globe (the bulbar conjunctiva). Coronally, the eyelids can be divided into two lamellae. The anterior lamella includes the superficial skin and orbicularis oculi muscle, whereas the posterior lamella consists of the tarsal plates, lid retractor muscles, and palpebral conjunctiva.

The lids meet each other at the medial and lateral canthal angles, while the palpebral fissure between them opens into the conjunctival sac and underlying globe. The lateral canthal angle is more acute than the medial, and it lies in direct contact with the globe. The more rounded medial canthus is separated from the globe by a small space, the lacrimal lake, which contains a small mound of tissue, the lacrimal caruncle. The lacrimal gland, situated in the superolateral part of the orbit, lies posterior to the orbital septum and the frontal bone. It secretes tears into the superior fornix of the conjunctiva that wash across the cornea to collect in the lacrimal lake in the medial canthus. Near the medial canthus, both upper and lower eyelids have small lacrimal papules on their margins that contain lacrimal punctor, through which tears drain into the lacrimal canaliculi and to the lacrimal sac. The sac then drains through the nasolacrimal duct to empty into the inferior meatus of the nose. The lacrimal sac lies in a protected position, behind the medial canthal tendon. It is enveloped by fibers of the orbicularis oculi muscle, such that each blink of the eyelids serves to pump tears through the sac and into the nose.

The temporal branch of the facial nerve is the most superficially located (and thus most susceptible) motor nerve in the periocular area. From its emergence beneath the parotid gland in the preauricular region, its course is roughly delineated by drawing one line from 0.5 cm below the tragus to a point 2 cm above the lateral end of the eyebrow and a second along the zygomatic arch.^3,4 The nerve is most superficial in the area of the zygomatic arch, and it is therefore most at risk to damage during a surgical procedure at this site. Anatomically, the four tissue layers of importance in the area of the lateral canthus are the skin and subcutaneous fat, the superficial muscular aponeurotic system (SMAS), the temporalis fascia, and the temporalis muscle. The SMAS is a thin layer of connective tissue that is continuous with the galea superiorly, the frontalis anteriorly, the occipitalis posteriorly, and the muscles of facial expression inferiorly. In the area of the temple, the temporal branch of the facial nerve runs just below the SMAS, within a layer of loose areolar tissue superficial to the temporalis fascia.⁴ At the lateral forehead the nerve dives under the frontalis muscle, becoming less vulnerable to surgical injury. The temporal nerve innervates the ipsilateral frontalis muscle and, to a lesser extent, the orbicularis oculi muscle, and nerve transection leads to weakness of the ipsilateral forehead with droop of the eyebrow and decreased ability to close the eye tightly. The importance of understanding the course of the facial nerve branches and their anatomic relationship to these tissue planes cannot be overstated.

The supraorbital and infraorbital nerves exit the skull via the supraorbital notch and infraorbital foramen, respectively, both located on a vertical line drawn from the medial corneal limbus. Moving clockwise from the supraorbital notch, the supratrochlear and infratrochlear nerves penetrate the orbital septum at the orbital rim. While localizing these can be useful in performing nerve blocks to anesthetize the eyelids and periorbital area, the nerves lie at such a depth that they are relatively protected from inadvertent transection during surgery.

The periorbital area has a rich vascular supply derived from both the internal and external carotid arteries. The ophthalmic artery arising from the internal carotid artery supplies the supraorbital, supratrochlear, dorsal nasal, and palpebral arteries. The superior and inferior palpebral arteries arch across the eyelids parallel to the lid margins, piercing the orbital septum above and below the medial and lateral canthal tendons. The external carotid artery contributes the remainder of the blood supply, including the superficial temporal artery, which emerges from beneath the parotid gland in the preauricular area. The superficial temporal artery’s frontal branch arcs across the temporalis muscle to supply the lateral eyebrow region as it anastomoses with the supraorbital artery, while the transverse facial artery courses over the zygoma to join the infraorbital artery in the lower eyelid. The facial artery ascends along the nasofacial sulcus to anastomose with the infraorbital and transverse facial arteries, above which the facial artery continues superiorly along the medial orbit as the angular artery, merging with the dorsal nasal artery superior to the medial canthus. Although such excellent vascular supply easily supports flaps and grafts in the periorbital region, the thin, distensible tissues can also predispose to significant postoperative ecchymoses. Meticulous intraoperative hemostasis is important in avoiding hematoma development.

Granulation (Second Intent Healing)

Some defects of the periocular area can be allowed to granulate with good functional and cosmetic results. In general, smaller wounds on concave surfaces can achieve excellent cosmetic results through granulation.⁶ In the periocular area, the concave profile of the medial canthus (and in some cases the lateral canthus) lends itself well to second intention healing, with one caveat. Wounds undergo significant contraction with granulation, and they should be monitored during this time to ensure that ectropion or epicanthal webbing does not occur. Contraction begins around the third postoperative day and rapidly progresses through an exponential phase until the completion of wound contraction, after which any remaining defect heals by scar deposition and reepithelialization.⁶ One recent study showed that wounds in the medial canthal area contracted approximately 78% when allowed to heal by second intent.⁶ Although such significant contraction means that the final scar will be significantly smaller then the original defect, the contraction can also significantly distort nearby free margins and anatomic landmarks such as the canthal angle. Pericanthal wounds selected to heal by granulation should be small (ideally less than 1 cm in diameter) and distributed equally above and below the canthus in order to minimize the chance of canthal displacement during wound contraction. Second intent healing in other periocular subunits gives variable results and has more risk for lid retraction and ectropion.⁶ Although some patients prefer the simplicity of second intent healing over primary surgical repair, several weeks of compliant daily wound care may be required. In debilitated patients or those with limited capability to monitor and clean the wound, primary repair is typically a better choice.

Side-to-Side Closure

The simplest method of wound repair for small to medium-sized periocular surgical defects is usually side-to-side closure. This often requires removal of adjacent redundant tissue to convert the circular defect into a fusiform shape to facilitate closure. The orientation of the ellipse should be designed to fall within or parallel to a wrinkle line, contour line, or RSTL. Since tissue is shifting (some classify large side-to-side closures as “sliding” flaps), care must be taken to avoid tension on free margins (eyelids, canthi) and landmarks (eyebrow, hairline). Since adjacent tissue moves perpendicularly to the long axis of a fusiform defect in side-to-side closure, the traction on the eyelid is maximal when the ellipse parallels the lid margin (Figure 12.6). Larger wounds (which necessitate more movement by adjacent tissues) and wounds closer to the lid margin provide greater risks of unacceptable traction on the lid. Therefore, the vectors of wound closure tensions should be parallel to the lid margin. The most direct way to do this, of course, is to orient the ellipse perfectly perpendicular to the lid.¹⁸ Since it is cosmetically preferable to orient the majority of the ellipse within wrinkles and other lines, one compromise is to curve the tip of the fusiform defect as it approaches the lid margin to be perpendicular to the margin near its border. In defects that diagonally approach the lid, sutures should be oriented parallel to the lid margin, rather than perpendicularly across the elliptical wound, to avoid unnecessary vertical tension on the lid. This closure technique may create slightly more redundant tissue (“dog-ear”) than placing sutures perpendicularly across the wound, but the prevention of tension on the lid margin is more important. Any resultant dog-ear can be “pushed” inferiorly through suturing technique and be subsequently removed away from the lid (inferiorly or laterally). Modified ellipses, such as the m-plasty technique, can also be used to shorten the length of the incision to avoid free margins and landmarks.^7–10

Figure 12.6 Side-to-side (elliptical) closures in the periocular area. Orienting ellipses along surface lines or RSTL (which parallel the lid margins) to maximize cosmesis must be balanced with minimizing tension on eyelid margins by keeping the vectors of tissue motion parallel to the lid margins. Ellipses within RSTL of the medial canthal area or surface rhytids of the lateral canthal area (A) are already oriented to minimize tension on the canthi. Very small ellipses (B) parallel to the lid margin can often be closed with acceptable tension. Orienting ellipses perpendicular to the lid margin (vector of tension parallel to lid margin) (C) results in the least lid tension possible. Placing sutures parallel to the lid margin (arrows, D) can instead be used to minimize lid tension. Curving the tip of the ellipse to be perpendicular to the lid margin, as in an S-plasty (E), can also decrease pull on the lid. Ellipses involving the eyebrow (F) should reapproximate the upper and lower brow borders and maintain the vertical brow dimension.

Skin Grafts

Skin grafts are another technically straightforward option for repairing periocular defects. The excellent blood supply of the region affords predictable success when proper technique is used. Full-thickness skin grafts (FTSGs) are preferred over split-thickness skin grafts, as full-thickness grafts undergo less contraction and produce better cosmetic results. Since FTSGs minimize wound contraction, they are often a good option to prevent unwanted tension on lid margins. Despite the fact that additional incisions are avoided and wound tensions are negligible, skin grafts are often cosmetically inferior to skin flaps. The results of skin grafting are directly related to the quality of the tissue match with the surrounding skin. Color, thickness, texture, and degree of sun damage must all be considered when selecting an ideal graft donor site. Although many donor sites can provide tissue to repair periocular defects, skin from the periocular aesthetic unit (the ipsilateral or contralateral eyelid) is the typically closest match. Retroauricular skin is of a similar thickness, and it is an acceptable alternative. Donor sites in the retroauricular fold eliminate the eyelid asymmetry that periocular graft harvesting can produce.

Skin Flaps

Functionally and cosmetically, local skin flaps are often superior to grafts for several reasons. Flaps retain their own blood supply, are less likely to undergo ischemic necrosis, and are more resistant to wound infection.¹¹ Flaps undergo less contraction than FTSGs, and they often have better color and texture matches because of their origins within adjacent skin. Adnexal structures usually survive well in periocular flaps and contribute to texture matches with the surrounding skin. However, flaps can be more technically difficult, and their successes are a function of how well they are executed.

Often, more than one flap will work well to repair a defect. Choosing the “best” flap in a particular situation involves considering many factors, including the patient’s goals (final cosmetic outcome or minimizing complexity of repair procedure) and the surgeon’s experience and comfort level. When evaluating a defect, the surgeon should first consider the nearby areas of relative tissue laxity (“tissue reservoirs”) that can contribute to a flap. The glabella, temple, upper eyelid, and cheek usually have some redundancy that can be utilized for flap creation. For laterally located defects, attempts should be made to base flaps temporally in order to keep the majority of the incisions away from the center of the face, where scars may be more noticeable. Also, flaps should be inferiorly based whenever possible to avoid chronic lymphedema from inadequate drainage (“pin-cushion” appearance). When superiorly based flaps are unavoidable, limiting the depth of incision and dissection will help to minimize the damage to the underlying draining lymphatics.

Most importantly, the surgeon should choose flaps that avoid tension on free margins and surface landmarks. With advancement and rotation flaps the “secondary movement,” which occurs opposite the primary movement of the flap, must be anticipated in order to minimize free margin displacement. With large flaps in this area, it is often necessary to use periosteal anchoring sutures to hold the weight of the flaps and minimize downward pull on the eyelid. In transposition flaps, maximal tension typically results from closing the secondary defect. A thorough understanding of the lines of maximal tension is important for successful execution of flaps in the periocular area.¹¹ Regardless of flap selection, the surgeon should prospectively envision the tension vectors that will be created by secondary movement and should test for adequate tissue extensibility using a thumb and forefinger (“pinch test”) prior to cutting any flap.

Eyebrow/Suprabrow Subunits

Figure 12.9 (a) A circular defect involving the brow and suprabrow units after Mohs micrographic surgery. (b) A single incision is made extending laterally from the defect along the border of the eyebrow to create a single-arm advancement flap. (c) In any flap involving the brow, it is important to undermine deep to the follicles to avoid damaging the eyebrow hairs. (d) The flap is advanced into the defect, with the direction of motion (and thus any resulting tension) parallel to the eyebrow and the upper eyelid. (e) Immediate postoperative result leaves the upper eyelid position unaltered.

Figure 12.10 (a) A larger defect after completion of Mohs micrographic surgery, involving the suprabrow, brow, and temple units. (b) In this larger single-arm advancement flap, the incision is continued past the lateral extent of the brow into the temple subunit to increase mobility. (c) Advancing the flap into position. Adequate undermining must be performed to maximize flap mobility (undermining should be restricted to the subcutaneous plane in the temple to stay superficial to the SMAS and avoid damage to the temporal branch of the facial nerve). (d) Immediate postoperative result, with maintenance of brow in neutral position. Note that bruising and edema have already begun to collect in the upper eyelid. (e) Postoperative result at 6 weeks.

Figure 12.11 (a) A circular defect involving the mid-brow. (b) A single lateral incision along the inferior border of the brow did not provide enough movement to close the defect easily, because of a tight temple in this patient. (c) Adding a second incision along the superior border of the brow (to create a double-arm advancement flap) can sometimes increase flap mobility. The incision angles must parallel the follicular shafts so as not to transect them (especially important along the inferior border of the brow, where follicular roots are easily transected); undermining must be in a subfollicular plane to avoid damage to the eyebrow. (d) Immediately after repair, with all redundant tissue sutured out along the edges of the flap. In patients with prominent eyebrows, incision lines can often be well concealed along the superior and inferior borders of the brow. (e) Immediate postoperative result; note significant upper eyelid edema. (f) Postoperative result at 7 days, just after suture removal; note resolution of upper eyelid edema.

Figure 12.12 (a) A circular defect in the suprabrow area after completion of Mohs surgery. (b) Bilateral single-arm advancement flaps (sometimes called “A-to-T” or “O-to-T”) are designed to close the defect. (c) Undermining is performed just above periosteum superiorly, but is kept within the subcutaneous plane medially (to avoid supraorbital nerve damage) and laterally (to avoid damage to the temporal branch of the facial nerve). (d) Flaps advanced into position and secured with key subcutaneous sutures; note standing cone has formed superiorly. (e) Standing cone has been removed, all subcutaneous sutures placed. Eyebrow and upper eyelid are maintained in neutral position. (f) Postoperative result at 7 months.

Repair of defects in either of these subunits can be considered together, as repair of either can affect the brow and upper eyelid position. Although not a free margin, the eyebrow is important in facial expression and its neutral position should be maintained. When closing a defect of the eyebrow, the surgeon should undermine at a plane beneath the hair follicles. Surface incisions should be parallel to hair follicles when possible to minimize the number of transected eyebrow follicles. Incisions along the superior border of the brow will be partially hidden by the upwards growing hairs, whereas those along the inferior border will be more apparent and must therefore be beveled downwards so as not to transect the most inferior follicles.

Upper Eyelid Subunit

Figure 12.13 This upper eyelid defect was closed with a combination of a transposition flap medially, and a FTSG laterally, required several flaps, and demonstrates how a full-thickness skin graft can replace significant lost tissue.

The upper eyelid usually has a significant amount of skin redundancy, and small defects can often be easily closed in a fusiform, side-to-side fashion. Primary closure scars are hidden most effectively when they fall within the upper eyelid crease or along the horizontal RSTLs of the lid. In cases where the defects are larger and linear closures may distort the lid margin or brow, a laterally based advancement flap is a good approach since it can utilize more of the lid’s laxity while keeping tension vectors parallel to the lid margin. Skin grafts can be used with caution, but the grafts should be designed so that they do not interfere with lid mobility—graft contraction could cause lagophthalmos (inability to completely close the lid) whereas oversized grafts could hinder lid retraction.

Lower Eyelid/Cheek Subunit

Figure 12.14 Orienting a side-to-side closure in the vertical dimension will both keep tension parallel to lower lid margin and result in an incision line along the nasofacial sulcus. Although it is not already well-defined in this patient, it is a natural border between the nasal sidewall and the cheek and offers a good location to hide a scar line.

Figure 12.15 (a) This defect lends itself well to a side-to-side closure that can be concealed within the nasojugal fold. (b) Sutures should be oriented parallel to the lower lid margin, rather than perpendicular to the closure line, in order to minimize tension on the lower lid. “Zipping” the defect closed superiorly to inferiorly (rather than by the “rule of halves”) will “push” the closure away from the eye, ensuring that any redundant cone of tissue can be removed away from the lid rather than extending it toward the medial canthus. (c) Immediate postoperative result. (d) Postoperative result at 7 days, just after suture removal.

Figure 12.16 An inferiorly based rotation flap is an excellent option for repair of this defect of the lower eyelid. (a) A circular defect of the lower eyelid after Mohs micrographic surgery excision of a skin cancer. (b) Inferiorly and laterally-based rotation flap designed and incised. (c) Flap is moved in to place. Note that the direction of motion is parallel to the lower eyelid margin. (d) Flap sutured in to place. (e) Final cosmetic result. There is no alteration of the eyelid margin.

The lower eyelid subunit is a challenging area for reconstruction, as repairs here produce higher risks of lid malposition and ectropion. Fusiform side-to-side closures can be hidden along the RSTLs, but as the size of the primary defect and the proximity to the lid margin increases, so does the risk of ectropion. In larger defects, flaps often provide more options to alter the vectors of tension and avoid pull on the lid margin. Ectropion can be a direct result of inappropriate flap design and the resulting tension vectors that pull the lid inferiorly. However, even in properly designed and executed repairs, the weight of temporary postoperative edema and expansion of soft tissue at the lid margin can contribute to the development of ectropion.

A special maneuver designed to counteract these temporary gravitational forces is the placement of a Frost suspension suture.¹⁸ Placement is straightforward: After completion of a flap or full-thickness skin graft that lies close to the lid margin and raises concern for tension, a suture is passed through the tarsus of the lower lid. Both ends of the suture are then attached to the overlying brow to create a suspension sling. The suture can be anchored at the brow with tape or sutured over a cotton bolster (Figure 12.17). Any type of suture may be used, and 4-0 nylon is an acceptable choice. Although some authors suggest placing the lid in its normal anatomic position, the lid may also be suspended slightly superior to its normal position to ensure there is no unwanted downward tension on the lid margin during healing. The suture placement through the tarsus and the anchoring points at the brow should be positioned so that vision is not obstructed and the cornea is not traumatized. Although the palpebral fissure will obviously be narrowed, the patient should still be able to see out of the eye in forward gaze. The suture is removed in 5–7 days, or as soon as most of the postoperative edema has resolved and thus reduced the risk of ectropion. Most importantly, the purpose of the suspension suture is not to correct an ectropion present at the time of closure (from improperly placed tensional forces) but rather to prevent it (by counteracting transient gravitational forces from edema).

Figure 12.17 Patients flap repair shown in Figure 12.16. (a) The Frost suspension suture should significantly raise the lower lid to counteract any gravitational forces. (b) The suture should not overlie the cornea; the pupil is not obstructed when in forward gaze.

Lateral Canthus/Temple Subunit

Figure 12.18 (a) A circular defect of the left temple after Mohs micrographic surgery. (b) Simple side-to-side closure oriented perpendicularly to the eyelids offers several advantages in this area. It allows recruitment of tissue laxity in the lower temple and lateral cheek, places the scar parallel to nearby periocular rhytids, and minimizes tension and displacement of the lateral canthus, eyebrow, and upper lid. Side-to-side closures of circular defects such as this almost always necessitate removal of standing cones on both sides of the wound, requiring extension of scar lines (compare the anterior extent of the defect in (a) to that of the incision line here). (c) Surgical result 3 months postoperatively.

Figure 12.19 (a) Small circular defect of the right temple after Mohs micrographic surgery. Although this defect is smaller than the one in Figure 12.18, it is slightly more inferior and closer to the lateral canthus. (b) In contrast to the side-to-side repair in Figure 12.18, this rotation flap design will keep the repair within the temple, away from the lateral canthus and the anterior view of the face. Lateral placement of the incision will conceal any long-term scar from the anterior view, and the wide pedicle and inferior drainage of the flap result in a predictably excellent cosmetic result in most cases. (c) Closing the “primary” defect first helps to ensure the flap is positioned to most effectively minimize tension on the eyebrow, upper eyelid, and lateral canthus. Then zipping the “secondary” defect closed from anterior to posterior serves to push the closure laterally, away from the central face, so that any standing cones can be removed along the hairline. However, the long curving incision usually allows the secondary defect to be gradually sutured out such that no “dog-ear repair” is needed. (d) Immediately after repair. (e) Surgical result 3 months postoperatively.

Side-to-side elliptical closures often hide nicely within lateral periocular rhytids. Laterally based rotation and transposition flaps keep most of the incision lines away from the frontal view of the face and appropriately redistribute the tension of closure. In some patients, the slight concavity of the temple subunit may make second intent healing an attractive option; in these cases, lateral canthal displacement during wound contraction is possible.

Medial Canthus/Nose Subunit

Figure 12.20 (a) A circular defect adjacent to the medial canthus after Mohs micrographic surgery. (b) A side-to-side closure was used to keep the direction of tissue movement parallel to the lower eyelid margin and take advantage of laxity in the lower eyelid and glabellar subunits in this patient. At the superior end of the defect, deep sutures placed through periosteum were used to pex the tissue down into the concavity of the medial canthus to avoid webbing. (c) This side-to-side closure was oriented in a vertical fashion to conceal it in the nasofacial sulcus, the natural junction of the nasal sidewall and the lower eyelid/cheek. This placement also minimizes tension on the lower lid since tissue movement is parallel to the lower lid margin. As in earlier examples of the lower eyelid subunit, the defect was closed to push any standing cones requiring removal inferiorly away from the canthus.

Figure 12.21 (a) A surgical defect on the junction of the medial canthus and nasal sidewall after Mohs surgery. (b) A full-thickness skin graft from the postauricular sulcus was used to repair the defect. Note the central pexing suture. (c) Good graft survival was noted 1 week postoperatively. (d) Unfortunately, contraction of the underlying wound bed can lead to the “pin-cushion” deformity, seen here in this one-month postoperative photograph. The appearance of the graft improved with subsequent intralesional steroid injections.

Figure 12.22 (a) A defect adjacent to medial canthus after Mohs micrographic surgery. (b) In this case, laxity of the nasal aspect of the upper eyelid was used to create a transposition flap. A deep pexing suture was placed within the undersurface of the flap to ensure it conformed to the concave contour of the medial canthal area. (c) Postoperative result at 1 week, just after suture removal.

Figure 12.23 (a) A deceptively “small” defect adjacent to the medial canthus after Mohs surgery. (b) Note how this defect “enlarges” as the medial canthal area is stretched with a finger. The concave shape of this subunit can lead to deceivingly large defects, which at first glance seem to have a small diameter since much of the “surface” area of the wound is concealed within the concavity. It is important to avoid undersizing flaps in the medial canthus to avoid anatomic alteration of the area. A glabellar transposition flap design is shown. (c) Glabellar transposition flap in place postoperatively. (d) Postoperative result at 1 week (just after suture removal), anterior view. (e) Postoperative result at 1 week (just after suture removal), side view.

The medial canthal area can be a difficult area to reconstruct, and there are multiple repair options for defects in this area. Because of its concave profile, the medial canthus is the most appropriate periocular subunit for second intent healing. Wound contraction can displace the canthus, however, so wounds optimally suited for granulation should extend evenly above and below the canthus. Canthal webbing can also be a distracting problem, and it should be avoided when reconstructing the area with cutaneous flaps. The glabellar area often has sufficient donor skin to contribute a transposition flap, as does the nasal sidewall and upper medial cheek. When designing a transposition flap, it is important to make certain that the tension vector used to close the secondary defect does not displace the eyelid or canthus.