Dermoid cysts are the most common periorbital mass lesions occurring in infants and children.1 They are choristomas that arise from the sequestration of surface ectoderm by closure of the underlying suture lines of the bony orbit. In the periorbital region, the most common location is at the lateral orbital rim adjacent to the frontozygomatic suture.1,2 Dermoids are asymptomatic mass lesions usually fixed to periosteum overlying the suture. They may enlarge slowly and are generally treated by surgical removal.
A direct incision typically is made over the bulk of the mass3 or, to better camouflage the scar, at the inferior border of the brow.2,4 An alternate approach is to make an incision in the eyelid crease below the lesion and then to dissect superiorly and laterally to expose and remove it. This approach has been my preference in 11 patients with lateral orbital dermoids, and has resulted in rapid healing of the incision, good scar camouflage, and excellent final cosmesis.
The procedure can be carried out under local anesthesia in older patients; general anesthesia is required in children. The approach is similar to the external approach for a ptosis repair.5 The lid crease is marked with gentian violet across the lateral half of the eyelid (Figure 1). The lateral tail of the lid crease is then directed superolaterally toward the lateral-most brow hairs to parallel the resting skin tension lines which, with age, will become visible as "laugh lines" in this region. A 4-0 nylon or silk suture is passed through the lid margin and clamped to the drape below, placing the eyelid on stretch. A skin incision is made with a no. 15 Bard Parker blade. The initial incision is usually carried out over the lateral half of the lid crease, ending at the level of the lateral canthus. This incision exposes the orbicularis muscle at the junction of its pretarsal and preseptal components. Toothed forceps are used to grasp the underlying orbicularis muscle and to "tent" it up. Blunt-tipped Westcott scissors are then used|to incise fullthickness through the orbicularis with one snip, thus exposing the post-orbicular fascial plane. This is identified as a white-translucent sheet of tissue immediately beneath the orbicularis, which consists of the confluence of orbital septum and levator aponeurosis. One blade of the Westcott scissors is then introduced through the opening posterior to the orbicularis, and the remaining blade remains anterior to the orbicularis and is used to open across the width of the skin incision.
Once the post-orbicular fascial plane has been exposed in this fashion, dissection then can be performed superolaterally between underlying septum and overlying orbicularis muscle. As dissection is carried up in this direction, the lid tissues can be retracted with Ragnell retractors or a Desmarres lid retractor. The overlying dermis is thin and elastic and remarkable displacement of the lid tissues can be achieved with undermining in the post-orbicular fascial plane to allow the incision to be displaced superiorly and laterally to expose the lesion (Figure 2). If the incision cannot be mobilized easily with undermining and retraction in this fashion, then it can be lengthened by successively incising additional medial portions of the eyelid crease with attendant undermining in the post-orbicular fascial plane.
FIGURE 1: Marking of lid crease incision beneath left superolateral orbital dermoid.
FIGURE 2: Superolateral retraction of the skin and underlying orbicularis muscle results in exposure of the dermoid fixed to the frontozygomatic suture along the lateral orbital rim.
FIGURE 3: Second patient with a more superior and laterally displaced dermoid of the lateral orbital rim.
FIGURE 4: Extension of the lid crease marking superolaterally into a "laugh line."
In lesions that lie particularly superiorly or laterally (Figure 3), the incision can be extended laterally in the previously marked "laugh line" as one would in performing an upper blepharoplasty (Figure 4). This superolateral extension of the lid crease incision should not extend beyond the lateral orbital rim at the junction of thin eyelid skin and thicker periorbital skin. The orbicularis is similarly opened with the Westcott scissors, and additional undermining to the depth of the orbicularis in the superolateral periorbital tissues will allow exposure of the periosteum overlying the frontozygomatic suture (Figure 5).
Once the dermoid is identified, it usually is separated easily from adjacent tissues with blunt dissection. Adhesions to periosteum may be freed bluntly but also may require sharp incision of the periosteum around the periphery of the dermoid. A periosteal elevator is then used to elevate the mass from the underlying suture; this can be facilitated by applying the cryoprobe for traction. Once the dermoid is delivered, hemostasis is obtained with bipolar cautery, and then skin closure is carried out with a simple running 6-0 "mild" chromic suture. If it has been necessary to extend the incision into the "laugh line" lateral to the canthus, then that portion is closed with interrupted sutures, taking care to slightly evert the edges of that portion of the wound not hidden in the lid crease, prior to suturing the lid crease portion of the incision. Interrupted absorbable sutures may be required to close the orbicularis lateral to the canthus. No attempt is made, however, to close the orbicularis beneath the eyelid crease. If hemostasis has been assured at the time of surgery, no patch is required. An ice pack is used as tolerated by the patient in the postoperative period. The mild chromic sutures usually dissolve in three to five days and can be rubbed off of the skin surface at the 1 week follow-up visit if they persist.
FIGURE 5: Exposure of lesion after incision in lid crease and "laugh line" and more extensive soft tissue undermining and retraction.
FIGURE 6: Appearance of the first patient on the first postoperative day. Note that the eyelid fold nicely camouflages the fresh incision.
FIGURE 7: Appearance of the second patient on the first postoperative day with more significant ecchymosis and swelling caused by the more extensive dissection through the lid crease approach.
FIGURE 8: Appearance of the same patient 2 months postoperatively. Note that the extension of the lid crease incision into the "laugh line" is already virtually imperceptible.
FIGURE 9: First patient's appearance 6 weeks after surgery with imperceptible scar.
This procedure has been performed on 11 patients ranging in age from 2½ to 23 years. The dermoids measured between 1 and 3 cm in diameter and were fixed to periosteum in the region of the frontozygomatic suture in all cases. In six cases removal was affected through a lid crease incision stopping at the lateral canthus, while five required extension of the incision laterally into a "laugh line" for adequate exposure. Follow-up has ranged from 3 to 18 months. There have been no postoperative complications, and in each case the patient has had an indistinguishable incision from the first postoperative day (Figure 6). In one case, the more extensive dissection required in this approach may have resulted in more postoperative ecchymosis and swelling (Figure 7) than might have been encountered with an incision placed directly over the dermoid. All soft tissue reaction, however, had completely resolved by the time of the patient's 3-week postoperative visit (Figure 8).
The surgical approach to subcutaneous lesions in the periocular region is dictated by two concerns: 1) the most direct approach to the lesion that minimizes unnecessary dissection; and 2) optimal scar camouflage. Traditionally the approach to lateral orbital dermoids has been carried out with incisions placed either directly over the orbital dermoid or at the inferior aspect of the brow. This has afforded good direct exposure of the underlying lesion and, when the incision has been placed at the inferior border of the brow, reasonably adequate scar camouflage. Because the skin in this region is thicker than that overlying the eyelid crease, however, prolonged erythema may occur and some depression of the mature scar often develops. Damage to the obliquely-oriented eyebrow follicles with resultant brow hair loss also may occur.
Incisions placed in the eyelid crease are ideally camouflaged because they are hidden by the lid fold when the patient's eye is open (Figure 9). Because this is the thinnest skin of the body, incisions heal most rapidly and leave imperceptible, fine line, mature scars. Scar contracture and formation of a depressed scar does not occur. The eyelid crease approach is particularly desirable in blond patients with light eyebrows, which offer little camouflage for an incision placed at the border of the brow. This approach is also preferred in females whose eyebrows are more arched and often lie higher above the orbital rim; in males, the lower position of the brow tends to throw an infrabrow incision into "shadow."
Incision through the lid crease results in a slightly less direct approach to the lesion. Dissection superiorly and laterally in the post-orbicular fascial plane is required to expose dermoids adjacent to the frontozygomatic suture. This is an avascular plane, however, and access to it is obtained easily by the surgeon familiar with the external approach for ptosis surgery. Because of the flexibility and distensibility of the upper lid tissues, even lesions that appear to lie fairly far from the lid crease can be exposed in this fashion, especially if lateral extension in a laugh line is used. As long as this lateral extension is stopped medially to the lateral orbital rim, the skin remains very thin and heals rapidly with a very fine scar. Large dermoids, in one case measuring up to 30 mm in diameter, can be approached successfully through the eyelid crease. The key to adequate exposure in such a case is to open the lid crease incision across the width of the eyelid, extending from the level of the punctum medially to the lateral extent of the laugh line at the lateral orbital rim. Undermining in the postorbicular fascial plane then allows wide displacement of the incision to adequately expose and remove these larger dermoids.
The less direct approach to the lesion offered by an eyelid crease incision may have resulted in increased postoperative swelling and ecchymosis in one patient. The increased dissection required for adequate exposure may increase the potential for more serious complications as well. The possibility that one might fail to appropriately identify the post-orbicular fascial plane and extend dissection posteriorly through the orbital septum and into the underlying levator aponeurosis must be considered. This problem has not occurred in my experience and would be an unlikely complication for any surgeon familiar with an external levator approach for ptosis repair.
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3. Grove AS: Dermoid, in Fraunfelder FT, Roy FH (eds): Current Ocular Therapy Two. Philadelphia, W B Saunders, 1985, p 192.
4. Putterman AM: Treatment of orbital tumors, in Peyman GA, Sanders DR, Goldberg MF (eds): Principals and Practice of Ophthalmology. Philadelphia, W B Saunders, 1980, p 2211.
5. Anderson RL, Dixon RS: Aponeurotic ptosis surgery. Arch Ophthalmol 1979; 97:1123-1128.