Summary of Cartilage Repair, Grafting, and Tissue Engineering

## Introduction Auricular cartilage refers to the cartilage of the external ear (auricle) that provides shape, flexibility, and structural support. This study material focuses on practical surgical considerations for harvesting auricular cartilage, donor-site management, and selected clinical applications that involve using auricular cartilage grafts and perichondrial procedures, excluding topics covered elsewhere such as cartilage biology, cartilage grafting theory, nasal reconstruction techniques, costal cartilage, and broad cartilage tissue engineering. > Definition: Auricular cartilage — the elastic cartilaginous framework of the external ear that maintains contour and provides a source of graft material for selected reconstructive procedures. ## Overview of Clinical Uses (practical focus) - Auricular cartilage is commonly harvested as a graft source for small structural needs in facial reconstructive surgery, and as a composite chondrocutaneous graft when skin plus cartilage is needed. - Perichondrium from auricular or rib sources can be used clinically to support regeneration or surface repair in selected applications. ## Principles of Auricular Cartilage Harvest ### Goals 1. Maximize usable cartilage harvest while preserving donor-ear appearance. 2. Prevent contour deformity, collapse, or unpleasant scarring. 3. Provide predictable closure techniques matched to graft size and location. ### Key anatomical areas used for harvest - Cymba concha and cavum concha — common donor areas for conchal cartilage. - Helical rim and base of helix — often used for composite (skin + cartilage) grafts. > Definition: Conchal cartilage — the cartilage forming the bowl (concha) of the external ear, divided into cymba concha (upper) and cavum concha (lower). ### Practical checklist before harvest - Mark the intended graft boundaries and preserve at least a minimal outer rim (see techniques below). - Consider leaving a lateral extension or portion of helical crus to act as a strut preventing collapse. - Plan closure method according to graft width and location. ## Techniques to Preserve Donor Ear Aesthetics Use these stepwise strategies depending on the graft size and site. ### Technique A: Maximal conchal cartilage harvest with preservation of contour - Mark cymba and cavum concha and a minimum 2-mm superior outer rim along the conchal wall. - Preserve at least 5 mm of the crus helicis with a lateral extension to support structure. - After cartilage removal, use a tie-over bolster or molded dressing to conform the conchal bowl and prevent contour depression. Fun fact: Studies have shown that careful preservation of a small helical crus extension and a 2-mm outer rim allows removal of large conchal grafts with almost no visible external evidence of harvest. ### Technique B: Small composite grafts (width < 1 cm) - Harvest from root of helix. - Close primarily by advancing adjacent skin and running the dog-ear anteriorly toward the hairline to preserve rim contour. ### Technique C: Composite grafts with cartilaginous base 1–1.5 cm - Wider composite grafts from helical base require more elaborate closure. - Close by distributing tissue movement: advance the dog ear anteriorly into hairline and posteriorly into triangular fossa; remove a full-thickness wedge of cartilage from triangular fossa to prevent buckling. ### Technique D: Harvests with width 1–1.2 cm from helix base - Primary closure may be possible by advancing the helical rim forward. - Anticipate possible overprojection of the ear; if present, a postauricular incision and scaphomastoid suture can reduce projection to match the contralateral ear. ### Technique E: Large composite grafts (> 1.5 cm width) - Simple helical advancement causes significant distortion and overprojection. - Use a V-shaped skin wedge closure combined with a “half-star” cartilage excision at the V apex to redistribute tension and avoid cupping. - Supplement with a postauri