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July 1985

Trapdoor Effect in Nasolabial Flaps: Causes and Corrections

Author Affiliations

From the Department of Otolaryngology—Head and Neck Surgery, University of Kansas Health Sciences Center, Kansas City, Kan (Dr Koranda); the Plastic Surgical Service, Melrose-Wakefield Hospital, Melrose, Mass (Dr Webster); and the Massachusetts Eye and Ear Infirmary, Boston (Dr Webster).

Arch Otolaryngol. 1985;111(7):421-424. doi:10.1001/archotol.1985.00800090035002

• The trapdoor effect is an elevated and bulging deformity of tissue within the semicircular confines of a U-, C-, or Vshaped scar. Various theories to explain this phenomenon are lymphatic and venous obstruction, hypertrophy of the scar, excessive fatty and redundant tissue, beveled wound edges, and contracture of the scar. Our data suggest that scar contracture is the predominant cause of the trapdoor effect in nasolabial flaps. For mild to moderately severe trapdoor deformities, multiple, small Z-plasties about the periphery of the nasolabial flap are indicated. Intralesional triamcinolone acetonide injections may produce a "pharmacologic Z-plasty" effect in some trapdoor deformities. For marked trapdoor deformities, the combination of multiple, small Z-plasties along the semicircular scar and peripheral undermining about the trapdoor defect is the corrective procedure. The trapdoor deformity may be prevented or lessened by peripheral undermining about the recipient site of the flap equal to or greater in area than the recipient site.

(Arch Otolaryngol 1985;111:421-424)

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