Neurocutaneous island flap:: an experimental model using the rabbit ear

The rabbit ear has often been used as an experimental model; however, a neurocutaneous flap has never been described before. The authors examined the reliability of a skin cartilage flap with a pedicle composed only of a sensory nerve with its vascular network in a rabbit model: A 2 x 2-cm cutaneous cartilage flap was harvested on the dorsal side of the ear bilaterally. Vessels were tied and cut on the 4 sides of the flap, including the central auricular artery and vein. The nerve was cut at the distal side of the flap and was "skeletonized" to the extent of 1 cm on the proximal side, meticulously preserving its vascular network. Subsequently, the flap was elevated with the cartilage as a composite flap and was sutured back to its natural site. The authors elevated 28 skin cartilage flaps on the dorsal side of both the ears of 14 New Zealand White rabbits, centered on the central neurovascular axis. All 28 flaps survived. In the control group of 7 rabbits, the artery, vein, and nerve (pedicle) were severed, and the skin cartilage island was sutured back as a composite graft. None of these 14 grafts survived. In 4 additional rabbits, the authors performed a histologic examination 1 day, 3 days, 7 days, and 3 weeks postoperatively of the neurovascular axis after the same skin cartilage flap was harvested. They compared these results with the histologic examination of the nerve of the contralateral nonoperated ear, and noted a marked dilatation and multiplication of blood vessels in the operated ear beginning on day 1 postoperatively. The presence of this neurocutaneous vascularization should be considered when other kinds of flaps (venous flaps or others) are used as experimental models using the rabbit ear.