Up to ten percent of skin cancers occur in the periorbital region1, with basal cell accounting for the vast majority (87%) followed by squamous cell carcinoma (7%).2 In a systematic review by Cook and Bartley, only two treatment modalities were found to have strong evidence supporting their use in the management of periocular BCC or SCC, Mohs Micrographic Surgery (MMS) and excision with frozen section or permanent section control.1 MMS is particularly suited for cutaneous tumors of the periorbital area because it preserves healthy tissue and ensures complete margin evaluation.3-4 Studies have shown that 29-69% of periocular defects are referred by Mohs surgeons to plastic surgery or oculoplastic surgery for repair.5,6 However, there is growing evidence suggesting that Mohs surgeons can safely perform eyelid reconstruction.5,6,7,8,9,10
When postoperative defects are limited to the skin and orbicularis muscle, they are easily repaired with full-thickness skin grafts (FTSG) or local cutaneous flaps, however, full-thickness eyelid defects that include tarsal plate and mucosa present a more complex reconstructive challenge. Defects of the posterior lamella that involve 50-100% of the eyelid margin have traditionally required lid-sharing procedures such as the Cutler-Beard flap (upper lid) and the Hughes tarsoconjunctival flap (lower lid).11 These interpolation flaps require the patient to tolerate monocular vision for up to three weeks prior to pedicle division. Such visual deficits for extended periods of time are universally difficult for patients and even dangerous and/or disabling in certain patient populations.
In 2021, Mori, et al. published a retrospective review of patients who underwent successful reconstruction by lateral canthotomy with inferior cantholysis by Mohs surgeons.10 Herein, we expand on this work to demonstrate the use of the periosteal flap technique to reconstruct larger, full-thickness eyelid defects. We propose that this single-stage procedure can be performed safely by Mohs surgeons with significant benefit to the patient, including a reduction in the number of office visits to multiple specialists, avoidance of complications of general anesthesia, potential cost savings to the healthcare system, and most importantly, preservation of binocular vision in the post-operative period.
Anatomy
A thorough understanding of eyelid anatomy is a prerequisite before attempting any repair. The upper and lower eyelids are divided into the anterior and posterior lamella. The anterior lamella consists of skin, connective tissue, and orbicularis muscle, while the posterior lamella consists of the tarsal plate and the palpebral conjunctiva. The upper and lower tarsal plates attach medially and laterally to their respective canthal tendons, together comprising the tarsoligamentous slings that support the eyelids. Addressing deficiencies of the anterior lamella, posterior lamella, and canthal tendons is critical to achieve an optimal aesthetic and functional outcome. Furthermore, it is important to utilize similar materials when reconstructing any of these components, for example, obliterated tarsal plate needs to be reconstructed with tissue that will provide a semi-rigid structure, oppose the globe, and provide a lining of nonkeratinizing mucosal epithelium so as not to abrade the cornea.
Surgical technique
For full-thickness lower lid defects that cannot be closed primarily, our approach is described as follows. We first attempt canthotomy with inferior cantholysis. If there is still too much tension on the wound, we extend the canthotomy incision as a Tenzel-style semicircular rotation flap. If there is still too much tension, a mucosal back cut can be made to release the full thickness lateral lid remnant to meet the residual medial lid; this leaves a deficit in lateral support and lining, and a periosteal flap can be elevated to replace the tarsal plate and support the repaired lid on the bony skeleton of the orbit (Video 1).
Prior to the procedure, proparacaine eye drops are administered and the patient is positioned and asked to look toward the unaffected side. This ensures that the pupil is at the maximum distance from the anesthesia needle. Tension is provided by retracting the lateral canthus and 0.25 to 0.5 cc of anesthesia is slowly injected with the needle oriented away from the globe at the interior aspect of the lateral orbital rim, providing anesthesia to the lateral aspect of the posterior lamella. The remainder of the surgical zone is anesthetized in standard fashion.
The authors use an internal eye shield to protect the globe during the procedure but recommend its removal prior to closure of the primary defect. After placement of the eye shield, the skin is prepared with povidone-iodine and draped in standard fashion. The primary Mohs defect should be converted into a pentagonal wedge shape, which will result in optimal positioning for closure.12
Mori et al. describes the technique for canthotomy with cantholysis. If closure cannot be achieved after following these steps, it can be due to restraint from the anterior lamella. In this case, a Tenzel semicircular rotation flap can be used for patients with 25-66% full-thickness lower lid defects.13 The canthotomy incision is extended superiorly and laterally from the lateral canthus in a semicircular arc. The flap is dissected in the pre-septal plane, posterior to the orbicularis muscle, until it is sufficiently mobilized so that the wound can be closed without tension. The flap is then elevated and rotated into position; anchoring sutures tether the flap to the periosteum of the medial aspect of the lateral orbital rim. The pentagonal wedge is closed primarily, and the flap is sutured into place. The procedure to repair the upper lid is the identical mirror image to that for the lower lid.
If the lateral eyelid can still not be mobilized sufficiently to allow for a low-tension closure, it is because of restraint from the residual mucosa. We make a vertical back cut through the mucosa of the affected lid at the lateral canthus, allowing the lateral lid remnant to advance medially to meet the medial lid remnant. A single diagonal tarsal suture approximates the eyelid margin.14 Medialization of the lateral lid remnant preserves native lashes, and results in lateralization of the eyelid defect.
Next, we use a laterally based periosteal flap to replace the posterior lamella thus providing support and lining in a single stage. Using the Tenzel incision for access, a strip of periosteum is incised at the inner aspect of the lateral orbital rim, approximately 5 mm in height and with a length corresponding to just greater than the distance needed to reach the tarsal plate remnant. The flap should be incised in the desired vector of the affected lid (Figure 1) and the superior aspect of the planned flap will determine the position of the lateral lid. The strip of periosteum is carefully elevated from lateral to medial around the curve of the orbital rim and hinged 180 degrees, maintaining its attachment point at the inner, lateral orbital rim. It is sutured to the remaining tarsal plate using 5-0 vicryl. Attention is then turned to the Tenzel flap, which is rotated into the defect and suspended with tacking sutures to the lateral orbital rim. Alternative options including skin grafts and other local flaps can be used to reconstruct the anterior lamella.