Simple is best for Mohs reconstruction

New York - Planning and performing a surgical reconstruction after Mohs surgery is usually a simple and straightforward task if the surgeon follows simple rules and implements simple techniques, according to Michael R. Shohet, M.D., director of facial plastic and reconstructive surgery at the Mount Sinai School of Medicine, New York.

"When performing an aesthetic facial surgery, the surgeon must be very careful to approach deeper structures in an atraumatic and minimally detectable manner, and the best reconstruction is one that is simple, restores function and has a good appearance," Dr. Shohet says.

Recurrent tumors, incompletely excised tumors, tumors greater than 2 cm in diameter or with ill-defined borders or sclerotic and finally tumors in areas of cosmetic concern (nasal tip/ala, upper lip, eyelids and ear) are all indications for Mohs surgery.

He further stresses that very large tumors, tumors invading nerves or bone and tumors with an aggressive histology are all likely to recur. He suggests that reconstructive surgery should be delayed 12 to 18 months with the tumors where recurrence is expected.

Types of reconstruction

Reconstruction can be achieved through secondary intention, primary closure, skin grafts, local flaps (advancement, rotation, transposition) and regional as well as distant flaps. Dr. Shohet explains how and when he implements a certain operative technique for a given anatomic location.

For the nose, he uses primary closure or local skin flaps on the dorsum, sidewall or tip for small defects and skin grafting or regional flaps (usually paramedian forehead) for larger defects. Axial flaps often benefit from a sculpting procedure prior to pedicle ligation, where the flap is optimally thinned and inset. This is especially useful is cases where the flap is unusually large or the blood supply is more tenuous.

The cheek offers laxity and an abundance of skin which can be helpful. Here, he either implements primary closure after fusiform excision for smaller defects, with 30-degree angled ends long axis oriented along favorable skin tension lines (FSTL) and aesthetic unit boundaries, or local flaps - transposition flaps such as a rhomboid flap.

He adds that this flap works well in the area of the cheek where the lower eyelid is involved and where lower lid eversion must be avoided. For large cheek defects, the surgeon uses a rotation flap of cheek and neck skin, elevating the flap superficial to SMAS, and cervicofacial rotation advancement flap for medial cheek defects. He extends the preauricular cheek incision into the neck and elevates the flap superficially to the platysma. Defects near the ala can be corrected with an advancement from the melolabial region with the base of the triangle adjacent to the defect and the point in the melolabial fold.

Forehead

On the forehead, Dr. Shohet handles small defects with primary closure after fusiform excision, and moderate defects through advancement, rotation and transposition flaps.

"Avoiding eyebrow distortion is important here," he cautions. "The surgeon must perform wide undermining, and if the skin on the forehead is too tight, closing the defect with a skin graft or through secondary intention may be a more suitable option."

The hairline and eyebrow must be considered when dealing with the temporal region. Smaller defects can be closed primarily with an M-plasty to shorten the scar. V-Y procedure can be implemented for moderate defects, and for larger defects, secondary intention, skin grafts or tissue expanders can all be used, Dr. Shohet says.

He operates small defects of the helix usually via primary closure, skin grafts or secondary intention. With large defects of the helix (those involving cartilage), he suggests to close the skin and leave a contour abnormality or to conduct staged cartilage grafting procedures.

Lip

"When approaching a defect on the lip, I close primarily or perform a bilateral advancement if the defect is centrally located and if only the skin is involved. For full-thickness lip defects (less than one-half lip width), I close the lower lip primarily, and if the lesion extends to the mental crease, I perform an M-plasty or lateral advancement," Dr. Shohet explains.

The surgeon suggests an Abbe flap (upper to lower lip switch) if additional tissue is needed. Here, tissue from the uninvolved lip is used as the donor.