INTRODUCTION

The medial eyelid/canthal area comprises an important anatomical region given its esthetical relevance and its intimate relationship with the eye and lacrimal apparatus. One major cause of medial canthal/eyelid defects are malignant skin cancers. The main goal in the reconstruction of any eyelid/canthal defect is to provide a good esthetic and functional outcome, ensuring integrity of the lacrimal apparatus and corneal protection.

A wide variety of local flaps can be used, as well as distant flaps in case of larger defects. Skin grafting is not advisable given the poor cosmetic outcomes.

In this article we describe the case of an 88 years old woman who suffered from a squamous cell carcinoma of the medial canthal region which was excised and repair using a contralateral split paramedian forehead flap.

CASE REPORT

We report the case of an 88 years old woman who presented with a medial canthal lesion affecting both superior and inferior medial eyelids of her left eye (Figure 1). Patient's informed consent was obtained. Incisional biopsy confirmed a squamous cell carcinoma moderately differentiated.

Figure 1. Pre-operative photographs. A medial canthal lesion affecting both upper and lower medial eyelids 

Preoperative CT showed a poorly defined lesion located in the medial canthal area of the left eye, in intimate proximity with the left nasal bone and periorbital fat (Figure 2). No pathological nodes were found.

Figure 2. Pre-operative CT images 

A conservative approach was decided in order to preserve her left eye, given the diminished visual acuity in her right eye due to a previous ophthalmic artery embolism. Surgical resection was performed including the left nasal bone, the medial canthal tendon, the lacrimal punctum and the upper portion of the lacrimal sac and both upper and lower eyelids in their most medial region including the conjuntiva. A right supratrochlear artery-based split paramedian forehead flap was designed, providing two axially perfused flaps for simultaneous repair of both upper and lower eyelids (Figure 3). The flap was elevated, rotated, passed over the nasal dorsum and then trimmed to fit the defect. A canthopexy with wires was performed, fixed to the contralateral nasal bone. Reconstruction of the conjunctiva was not performed. A silicone tube was placed in the left nasolacrimal duct for three weeks to maintain drainage. The donor site was closed primarily.

Figure 3. Surgical resection performed, contralateral split paramedian forehead flap designed 

Histopathological analysis confirmed the previous biopsy: infiltrating squamous cell carcinoma with a maximum thickness of 10 mm. Perineural invasion was found. The lachrymal glands were found free of disease.

A follow up photograph is shown (Figure 4). Adjuvant radiotherapy was considered. Satisfactory esthetic outcomes were achieved. No revision surgery was considered. The patient remained free of disease during the 2 year follow-up.

Figure 4. Post-operative photograph 

DISCUSSION

Skin cancer is a major cause of medial eyelid/canthal region defects, being basal cell carcinoma the most frequent type (80 %). ¹ followed by squamous cell carcinoma.

Reconstruction of medial eyelid/canthal defects is technically challenging because of the remarkable important function and esthetics of the lids². Difficulties arise from the necessity to restore different type of tissues at the same time: skin, tarsus, muscle, conjunctiva, etc. ³. Sometimes a canthopexy may be needed.

Defects larger than one-third of the length of the eyelid require the use of flaps. ⁴. Microvascular flaps can be used when larger defects are found. However, local flaps are to be the workhorse in this type of defects.

Paramedian forehead flaps and their following modifications have been widely used to repair nasal defects, as well as medial canthal areas. It offers a large portion of donor tissue for large, complex defects⁵ of the medial eyelid/canthal area. It is an axial patterned flap based on the supratrochlear artery⁶. Blood supply is so reliable that a narrow pedicle can nourish a relatively large flap⁷. The main disadvantage is the thickness of the flap, so that debulking and thinning may be necessary, which implies a risk of jeopardizing the vascularity and subsequent flap failure.

One modification of the paramedian forehead flap is the split paramedian forehead flap, presented in this article. Its main advantage is its suitability to repair both eyelids simultaneously.

We want to highlight the importance of performing a canthopexy to achieve optimal esthetical results, enhancing the medial canthal contour and reducing medial canthal webbing.

In conclusion, the paramedian forehead flap is a versatile and reliable that should be considered when a defect in the medial eyelid/canthal area is found. Its ease to harvest and minimum donor-site morbidity make the paramedian forehead flap a simple yet satisfactory flap in medial canthal repair.