When doing the cheek rotation flap to fill the defect in the medial aspect of the lower lid, the incision should be carried above the lateral canthus and around to the cheek and down in front of the ear. The dissection on the cheek should be performed through the fat layer beneath the skin, taking a sufficient amount of fat along with the skin and subcutaneous tissue. This will preserve the vascular supply to the flap. Since the branches of the seventh nerve lie on the fascia deep to the muscles, it is unlikely that this type of dissection will interrupt the nerve fibers. Dissection should be continued until the flap can be brought in to cover the entire defect without tension. The deep tissues of the flap are secured to the periosteum in the area of the lateral orbital rim, in order to counteract a tendency for the flap to pull inferiorly and cause a lateral ectropion of the lower lid.

335

FULL-THICKNESS SKIN GRAFTS

If neither advancement flaps nor primary closure appear to be sufficient to close an eyelid defect not involving the lid margin, full-thickness skin grafts can often give very satisfactory results (335–339). Although contracture of a full-thickness graft is not usually a significant problem, the graft should be slightly larger than the defect. Retroauricular skin or upper eyelid skin is the best match for a graft to the eyelid. To determine the exact size of the graft, it should be placed in the recipient bed so that the underside of the graft lies flush with the deep tissue within the defect. Grafts heal best if placed immediately after tumor removal. When working with a Mohs surgeon, it is best to repair with a graft on the same day as the cancer surgery (see Chapter 7 and 55–57).

REFERENCES

1.Putterman AM (1977). Semicircular skin flap in reconstruction of nonmarginal eyelid skin defects. Am. J. Ophthalmol., 84(5): 708–710.

2.Mustarde JC (1980). Repair and Reconstruction in the Orbital Region. A Practical Guide, 2nd edn. Churchill Livingstone, Edinburgh, pp. 33–68.

MEDIAL CANTHAL DEFECTS

GENERAL CONSIDERATIONS

Tissue loss in the medial canthal area may involve only skin and subcutaneous tissue. In these cases, the principles of repair will be similar to those principles used in repair of eyelid defects not involving the eyelid margins (Chapter 10: Repair of Defects Not Involving Eyelid Margins). However, in most cases, medial canthal tumors lie close to the lacrimal drainage system and the medial aspects of the upper and/or lower lids. The principle of complete excision of a tumor using microscopic evaluation is especially important in the area of the medial canthus since residual tumor can spread along the sinuses and, eventually, into the brain. It is, therefore, prudent to remove all of the tumor without regard to the underlying lacrimal drainage system or the adjacent eyelids. With this approach, most medial canthal defects will have an associated eyelid margin defect and, often, a lacrimal drainage system defect.

Repair will then consist of filling in the skin and subcutaneous defect, repairing an eyelid defect, and perhaps repairing the lacrimal drainage system. If the attachment of the medial canthal tendon to either eyelid is interrupted, scar formation during the healing process would tend to pull the eyelid away from the globe. It is, therefore, important to re-approximate the medial aspect of either eyelid to the medial canthal tendon, or at least to the area where the medial canthal tendon should be.

Postoperative facial contours will be closer to normal if the concavity of the medial canthal area is preserved. When filling in the defect with flaps or grafts, the donor tissue should be tied securely to the area of the medial canthal tendon. If this is not done, subcutaneous serum or blood can push the graft or flap anteriorly, thereby eliminating the medial canthal depression.

If the lacrimal sac is partially sacrificed or if both canaliculi are interrupted, reconstruction of the lacrimal drainage system can usually be deferred to a later date. In the older person, tear production is diminished, and epiphora will not often be a problem in spite of the loss of the lacrimal drainage system.

If part of a canaliculus is excised or the lacrimal sac is removed to some degree, tubes can be placed in the lacrimal drainage system and the system allowed to epithelize over these tubes. If the punctum and lateral part of the canaliculus are spared and there is some canaliculus attached to the lacrimal sac, silicone tubing can be passed through the canaliculus to bridge the missing part. The canaliculus is then sewn over the tube with fine absorbable sutures. For monocanalicular injuries, the author prefers the Monoka system.1 If the lateral part of the canaliculus, including the punctum, is sacrificed, a silicone tube can be passed through the remaining canaliculus into the nose. The distal end is stitched to the skin of the nose. The lateral part of the remaining canaliculus is marsupialized into the inferior cul-de-sac. This maneuver is not highly successful, but the downside is minimal (245–255).

The author has seen a case in which both canaliculi were removed during tumor resection, but the lacrimal sac was left intact. When healing was complete, an epithelial-lined path had formed between the medial lacrimal lake and the lacrimal sac. Tears drained spontaneously into the lacrimal sac. However, bubbles from the lacrimal sac also came out at the medial canthal angle on occasion.

SPONTANEOUS GRANULATION

Spontaneous granulation was first described by Sidney Fox and Crowell Beard in 1964.2 The reason behind allowing granulation to occur was that increased bleeding in this very vascular area might cause failure of a graft to become viable. If there was extensive tissue loss and only bone remained at the base there would be no recipient site for the graft.

more lax and could be pulled in the direction of the granulation tissue. This might result in an ectropion of either eyelid, or a migration of the medial canthal angle toward the nose (347–352).

If the medial aspect of either eyelid is involved in the defect, the eyelid can be repaired with an advancement flap as described in the section on medial eyelid defects (Chapter 7: General principals of Eyelid Reconstruction and Radiosurgery and 8: Lower Eyelid Reconstruction). When this has been accomplished, and the eyelid or eyelids are placed in their proper position in the medial canthal angle, the rest of the defect can be allowed to granulate

Medial Canthal Defects 115

spontaneously. Large defects can be repaired with spontaneous granulation in combination with advancement or rotation flaps, as described in the subsequent sections within this chapter.

The texture of the new skin following spontaneous granulation is usually a very good match with the surrounding skin. The medial canthal concavity is also well preserved when spontaneous granulation is allowed to occur. A common occurrence following spontaneous granulation is the appearance of conjunctival granulation tissue. This tissue is easily excised and usually does not recur.

FULL-THICKNESS SKIN GRAFTS

If the medial canthal defect has vascular soft tissue, a good result can usually be expected with a full-thickness skin graft (353–358). Retroauricular skin is an excellent source for a medial canthal skin graft. The graft is prepared as described in Chapter 7: (General Principals of Eyelid Reconstruction and Radiosurgery) and placed in the medial canthal area. Special attention should be paid to the medial canthal

concavity by placing several sutures through the graft to attach it to the medial canthal tendon or tissue in this area. Absorbable sutures such as 5-0 chromic gut or 5-0 polyglactin 910 are used to suture the graft to the deep tissues. 6-0 or 7-0 nylon can be used to attach the graft to the surrounding skin. A Telfa bolster may be tied over the graft with 5-0 silk sutures and left in place for 3–5 days, but is not usually necessary. Skin sutures are removed in 6–8 days.

354

356

358

355

357

354–358 Retroauricular graft. 354: Full-thickness retroauricular skin graft in place four days after a medial canthal basal cell carcinoma has been removed. Note the purple hue indicating that vascularization is beginning to occur, and, also, note several defects in the graft which allow the egress of subcutaneous fluid. 355: Same patient three months following a graft to the left medial canthus. 356:Young male with basal cell carcinoma in the right medial canthus. 357: One week following retroauricular skin graft. 358:Ten months after surgery: the graft is not the exact skin match but the contour of the medial canthus is good.

ADVANCEMENT AND ROTATION FLAPS Advancement flap

If there is sufficient tissue surrounding the medial canthal defect, flaps can be used with very satisfactory results. Care must be taken when closing the donor defect to preserve the normal configuration of the eyelids. If the medial aspect of one or both eyelids is involved in the tumor resection, the eyelid(s) can be advanced medially as described in the section on medial eyelid deformities (Chapter 8: Lower Eyelid Reconstruction and 9: Upper Eyelid Reconstruction). The medial canthal defect can then be repaired with an advancement flap.

359 Double advancement flaps. An inferior and a superior advancement flap are brought to meet one another to fill the medial canthal defect. Note that the superior flap is tied to the area of the medial canthal tendon using mattress sutures that can be absorbable or nonabsorbable.

360

360–362 Double advancement flaps for a medial canthal defect. 360: Basal cell carcinoma in the right medial canthus. 361: One week

postoperative, showing the sutures which are still in place outlining the advancement flaps from the areas superior and inferior to the defect. 362: Medial canthal configuration is preserved seven weeks following surgery.

Medial Canthal Defects 117

Advancement flaps are best brought from an area superior or inferior to the defect and, in some cases, a double advancement flap can be used. The skin and subcutaneous tissue are undermined under the advancement flap. If it is a single flap, the appropriate area of the flap is secured to the medial canthal tendon. If the flaps are brought from above and below, they can meet in the area of the medial canthal tendon. The sutures that attach the flaps together can be passed through the medial canthal tendon to preserve this medial canthal concavity. The rest of the skin is usually closed with a small suture such as 7-0 polypropylene, 6-0 nylon, or silk (359–362).

359

361

362

Myocutaneous island flap

Myocutaneous island flaps can be used if there is not sufficient tissue laxity to perform advancement flaps (216, 363). A single myocutaneous flap or double myocutaneous flap may be appropriate to fill a medial canthal defect. The flap is fashioned by outlining a triangle of skin with its base being the inferior or superior margin of the defect. The

363 Double advancement myocutaneous eyelid flaps. a: Medial canthal defect showing the outline of triangular flaps. b:Triangular flaps are fashioned. c:The triangles are advanced to meet one another. d: Skin closure.

other two sides of the triangle are incised, and the subcutaneous tissue and muscle beneath the apex of the triangle are also incised. This leaves a muscle attachment beneath the base of the triangle. The muscle pedicle serves as a blood supply to the island of skin which is trimmed and advanced into the defect. As with the other advancement flaps, the appropriate tissue should be sutured into the medial canthal tendon area and then the skin closed with 6-0 silk or 6-0 nylon sutures. Primary closure is used in the area from which the triangle was taken.

‘V’ to ‘Y’ rotation flap

A rotation flap can also be used to fill a medial canthal defect. This flap can be taken from the glabellar area or it can be taken from the area inferior to the medial canthal defect. The rotation flap from the area above the nose can be fashioned as a ‘V’ and closed as a ‘Y.’ Undermining is done, and a flap of skin and subcutaneous tissue is then rotated into the defect. Primary closure is used in the area between the brows (364–371). The rotated flap is then sutured to the tissues in the medial canthus, and also to the eyelid tissues if the eyelids have been involved in the resection.

364

a

b

c

364 Glabellar ‘V’ to ‘Y’ rotation flap. a:Tumor in the right medial canthus. Dotted lines indicate ‘V’ incision. b: Flap is undermined and rotated to fill the defect. c: Skin closure is done in a ‘Y’ fashion.

Midline forehead flap

If a midline forehead flap is used, the rotation flap is outlined (372) and brought into the recipient bed. The skin that fills the defect in this method comes from the forehead area and is, therefore, significantly thicker than skin adjacent to the medial canthal defect. Using thick skin makes preservation of the medial canthal contour difficult, and a secondary procedure may be needed to thin the skin. The donor site is closed primarily. This method should be used if other techniques are not appropriate, since the cosmetic appearance may be less satisfactory.

Cheek rotation flap

A cheek rotation flap can be used if the defect is in the lower aspect of the medial canthus. The flap is formed by undermining an area where the medial aspect of the cheek meets the lateral aspect of the nose and bringing this flap superiorly into the defect (373–377).