A Hybrid Auricular Framework of Autologous Rib Cartilage and a Porous Polyethylene Implant for Reconstruction of Congenital Microtia: A Modification of Nagata's Technique

Abstract

Background: An implant (porous polyethylene) is an alternative to rib cartilage for microtia reconstruction but carries a risk of extrusion. Objective: To evaluate the outcome of a hybrid framework of implant with rib cartilage for microtia reconstruction. Methods: Patients who underwent Nagata's technique for microtia reconstruction were reviewed for complications and aesthetic score. In stage 1, a rib cartilage framework or a hybrid framework of implant with rib cartilage was used. In stage 2, the framework was elevated and supported by an implant for projection. Postoperative outcomes were reported for both groups. Results: Forty-four ears of 40 patients underwent surgery. Eleven ears received a rib auricular framework and 33 ears a hybrid auricular framework. The mean postoperative follow-up for the rib and hybrid groups was 76.3 and 43.1 months, respectively. No supporting postauricular implant extruded, whereas stainless-steel wires extruded in seven ears (15.9%). Five (15.2%) hybrid frameworks were removed due to infection or extrusion. Mean operating time was 2 h shorter in the hybrid group. Aesthetic outcomes were similar for both groups. Conclusion: A hybrid framework of rib and implant that requires less harvested cartilage is feasible for microtia reconstruction, but caution should be used due to its higher explantation rate.

Fig. 1.

Surgical technique for reconstruction of the auricular framework by rib cartilage alone or combination rib cartilage and porous polyethylene. (A) Rib cartilage was harvested from the 7^th rib on either the ipsilateral or contralateral side of the chest. (B) The helix (red), antihelix (blue) and antitragus (green) were formed from either side of the lateral border of the 7^th rib cartilage. (C) The template of the ear is copied from the opposite ear. (D) An auricular framework is formed from autologous rib cartilage (ACC). (E) The base of the auricular framework was constructed from either a porous high-density polyethylene “Siegert” auricular prosthesis (Stryker, Kalamazoo, MI) with the helix and antihelix shaved out, or carved from a polyethylene implant block [63 mm (Length) × 30 mm (Width) × 6 mm (Thickness)] (Stryker, Kalamazoo, MI) using a surgical burr and scalpel. The scaphoid fossa, triangular fossa, concha symba and concha cavum are formed with a cutting burr. (F) A hybrid auricular framework is formed by binding rib cartilage to the base of the polyethylene implant with stainless-steel wire to form a helix, antihelix and tragus. Perichondrium (white arrows) is placed to cover the polyethylene implant in the region of the earlobe.

Fig. 2.

Intraoperative photographs showing microtia reconstruction by a modified Nagata's technique for stage 1 and stage 2 operations using rib cartilage and a porous polyethylene. (A) An ‘S’ incision (small black arrows) is made in the preauricular, auricular and postauricular region to prepare for the elevation of the skin flap and to allow transposition of the earlobe. A skin pedicle attached to the mastoid region is preserved (black shaded area with white arrow). The position and orientation of the auricular framework is planned according to the opposite ear. (B) The skin flap is elevated with a skin pedicle remaining attached to the mastoid fascia (white arrows) which allows the earlobe to be transposed. The remnant of the ear cartilage is removed (black arrows). (C) A template of the opposite ear is prepared using a plastic film to facilitate carving of the porous high-density polyethylene implant block. (D) The base of the auricular framework is carved from a polyethylene block to form a scaphoid fossa, triangular fossa, concha symba and concha cavum. (E) Addition of the helix, antihelix, antitragus and tragus by autologous rib cartilage (small black arrows) to the polyethylene implant to form a hybrid graft. Rib cartilage is also added to cover the earlobe region of the framework (large black arrows). (F) Placement of the hybrid auricular framework deep to the skin pocket with the pedicle of the skin flap located in the concha cavum. (G) The shape of the auricle after placement of the hybrid auricular framework and transposition of the earlobe. Redundant skin is excised. (H) Appearance of the auricle after stage 1 reconstruction while undergoing stage 2 reconstruction to create auricular projection. (I) The auricular skin is peeled off from the hybrid auricular framework to allow excision of redundant fibrofatty tissue in the scaphoid fossa and triangular fossa. An intact helix (white arrows) and antihelix (black arrows) by autologous rib cartilage and good bio-integration of the soft tissue to the polyethylene base are seen. (J) A temporoparietal fascial flap is harvested from the temporal region by an external skin incision. (K) Elevation of the hybrid auricular framework and the skin from the mastoid to create a postaural sulcus (white dotted line). (L) A wedge of polyethylene implant is carved according to the requirement for projection based on the opposite ear. (M) The polyethylene wedge is placed in the postaural sulcus to check the auricular projection which is then covered by vascularized temporoparietal fascia (white arrows). The cervical skin is advanced superiorly to cover the postaural defect posterior to the earlobe (black arrows). (N) The projection of the hybrid auricular framework is achieved after placement of the polyethylene wedge covered by vascularized temporoparietal fascia (white arrows). (O) A full thickness skin graft is harvested from the lower abdomen and the wound closed primarily. (P) The immediate postoperative appearance of the auricle after Nagata s stage 2 reconstructive surgery with a closed suction drain to prevent a hematoma and to maintain negative pressure for better skin binding to the auricular framework.

Fig. 3.

Appearance of the auricle before and after microtia reconstruction using the rib cartilage and hybrid auricular framework made with a rib cartilage and porous polyethylene. (A) (Left): Lobular type of microtia. (Middle): Reconstruction by a rib auricular framework. (Right): Postaural sulcus. (B) (Left): Small conchal type of microtia. (Middle): Reconstruction by a rib auricular framework. (Right): Postaural sulcus. (C) (Left): Small conchal type of microtia. (Middle): Reconstruction by a hybrid auricular framework. (Right): Postaural sulcus. (D) (Left): Lobular type of microtia. (Middle): Reconstruction by a hybrid auricular framework. (Right): Postaural sulcus. (E) (Left): Lobular type of microtia. (Middle): Reconstruction by a hybrid auricular framework. (Right): Postaural sulcus. (F) (Left): Large conchal type of microtia. (Middle): Revision reconstruction by a rib auricular framework as salvage surgery after explantation of a hybrid auricular framework caused by persistent infection. (Right): Postaural sulcus.