Reconstruction of the soft tissues of the head following trauma or tumour excision requires a high level of surgical planning. In countries with high ultraviolet levels, resection of squamous cell carcinoma from the nasal plane and lip, forehead, ears and eyelids of cats presents a particular challenge. Other cases requiring reconstructive surgery of the head that have been treated by the author recently include fibrosarcoma and osteosarcoma of the nasal bones and orbit and mast cell tumours in cats.

Reconstruction of the Forehead

Reconstruction of the forehead following tumour removal should be undertaken carefully, especially when a skin defect is created close to the upper eyelid. Closure with minimal tension using techniques that result in primary intention healing with little risk of contracture of the eyelid should be employed whenever possible. Large skin deficits of the forehead may be closed using a V-Y advancement flap based between the ears (Figure 1) or a rotation flap from between the ears or using loose skin from the side of the face.

Reconstruction of the Skin of the Orbit

Wound closure following enucleation and/or orbitectomy is best achieved using the caudal auricular axial pattern flap. This flap is based on the caudal auricular artery that arises between the base of the ear and the wing of the atlas and proceeds caudally before anastomosing with branches of the superficial cervical artery. A long flap may be created with its base near the wing of the atlas, and may be rotated through 180 degrees to close defects of the lateral face and forehead.

Reconstruction of the Bridge of the Nose

Reconstruction of the bridge of the nose following tumour excision may be achieved by using an advancement flap between the ears and eyes, utilising the loose skin on the back of the neck (Figure 2). Parallel incisions are made on either side and extended back beyond the nuchal crest. A close attachment between the skin of the head and the nuchal crest/occipital area must be divided in order to enable the skin to stretch forward.

	Figure 1. Use of a V-Y advancement flap to close a forehead defect without exerting tension on the eyelids.
	Figure 2. Diagram showing use of advancement flap from between the ears to close a defect of the bridge of the nose. This technique is useful for cats as well as dogs.

Reconstruction of the Lower Eyelid

The mucocutaneous subdermal plexus flap was first described in 1982 by Pavletic and colleagues for restoration of the lower eyelid in the dog. Squamous cell carcinoma is a common tumour of cats in Australia. Surgical excision of squamous cell carcinoma with wide margins is the most consistently effective treatment and often involves resection of part or all of the eyelid. Many cats do not require enucleation for disease control, in which case reconstruction of the lower eyelid is ideal if not mandatory.

Veterinary surgeons in areas with a high incidence of squamous cell carcinoma will be faced with the necessity of preserving lower eyelid function in cats who do not require enucleation. Other techniques for eyelid reconstruction including use of nictitating membrane conjunctiva in combination with local transposition flaps, a semicircular flap technique, a split eyelid flap and transplantation of oral mucosa as a free graft. The lip-to-lid fold, however, is a straightforward, single-stage procedure that is associated with minimal sequelae. The author has successfully used the lip-to-lid fold to reconstruct lower eyelids in a number of cats. The reconstructed eyelid functioned normally in protection of the cornea and distribution of the tear film.

Surgical Technique

The patient is placed in lateral recumbency and the side of the face prepared for sterile surgery. A protective ointment is placed in the eye.

The affected eyelid is excised using sharp dissection. A composite mucocutaneous flap is raised using the caudal portion of the upper lip, according to the original description by Pavletic et al. (1982) (Figure 3, dotted lines). The commissure of the lip is less desirable than the caudal segment of the upper lip, as it tends to have a less defined mucocutaneous junction and does not mimic the normal eyelid margin as well. Care is taken to ensure that the base of the flap is not unduly narrow.

Figure 3. Rotation of a flap created using the caudal upper lip in order to reconstruct the lower eyelid.

A bridging incision is made between the base of the flap and the defect left by excision of the eyelid. The flap is then rotated into the defect (arrow), so that the mucocutaneous junction of the lip becomes the margin of the reconstructed eyelid. The buccal mucosa of the flap is sutured to the edges of the conjunctiva using single interrupted sutures of 1 or 1.5 metric polyglactin, with buried knots. The buccal mucosa, subcutaneous tissue of the donor site and skin edges are sutured using single interrupted sutures of 1.5 or 2 metric polyglactin or polypropylene. A broad-spectrum antibiotic (amoxicillin/clavulanate, 12-20 mg/kg) is administered perioperatively and for 48 hours postoperatively. Eye ointment containing antibiotics is applied to the affected eye once daily.

As long as good surgical principles are employed, including gentle tissue handling, preservation of blood supply and maintenance of an appropriate base, good results can be expected. Surgeons should, however, bear in mind that this is a subdermal plexus flap and is therefore not served by a direct cutaneous artery. Therefore, in some cases flaps may approach the safe limit of their blood supply. Ample tissue is available using this technique to permit eyelid reconstruction as well as defects medial and lateral to the canthi, should it be necessary.

References

1.  Hunt GB. Lip-to-lid skin fold for reconstruction of the lower eyelid in 5 cats. Veterinary Surgery 2006; 35: 284-286.

2.  Pavletic MM, Nafe LA, Confer AW. Mucocutaneous subdermal plexus flap from the lip for lower eyelid restoration in the dog. Journal of the American Veterinary Medical Association 1982; 180: 921-926.