Pinna (Auricular) Reconstruction - Detailed Review

Overview and Surgical Options

1. Congenital microtia/anotia - the most common indication
2. Traumatic auricular avulsion or defects
3. Post-oncologic defects after tumor excision

1. Observation (no intervention)
2. Adhesive or implant-retained prostheses
3. Alloplastic reconstruction with porous polyethylene (Medpor/SuPor)
4. Autologous costochondral cartilage reconstruction (gold standard)

Classification of Microtia (Basis for Surgical Planning)

• 1st degree dysplasia: Most normal structures present; reconstruction does NOT require additional skin or cartilage
• 2nd degree dysplasia: Some structures recognizable; partial reconstruction requires some additional skin and cartilage
• 3rd degree dysplasia: No normal structures recognizable; total reconstruction requires skin AND large amounts of cartilage

• Grade 1: Smaller but all structures present
• Grade 2 (conchal type): Some structures absent, concha still identifiable
• Grade 3 (lobular type): Only the lobule present
• Grade 4: Anotia

Timing of Surgery

• Autologous rib cartilage harvest requires sufficient donor cartilage - typically 8-10 years of age (when 85% of adult pinna size is reached)
• Nagata/Firmin frameworks are more complex and delay surgery to age 10 years due to greater cartilage volume requirements
• Brent's technique can begin at 6-8 years due to simpler framework design
• Alloplastic (Medpor) reconstruction can be performed earlier (from age 3)
• Atresia repair, if planned, is performed after microtia reconstruction

1. AUTOLOGOUS RIB CARTILAGE RECONSTRUCTION

A. Brent's Four-Stage Technique

• Harvest costal cartilage, typically the 7th and 8th ribs with a margin of the 6th rib cartilage ("floating rib")
• Sculpt cartilage into the auricular framework - a base, antihelical fold, scapha, and helix
• Create a subcutaneous pocket in the correct anatomical position and orientation on the lateral skull
• Insert the framework into the pocket; small suction drains are placed to ensure thin skin adheres to the framework

• Approximately 3 months after Stage 1
• The soft tissue remnant (vestigial lobule) is translocated into the correct lobule position
• Brent's technique deliberately delays lobule transposition, allowing the pocket to stabilize first

• Elevate the framework off the lateral skull to create retroauricular projection
• A split-thickness or full-thickness skin graft (FTSG) is placed posteriorly to create the postauricular sulcus
• A wedge of banked cartilage is placed behind the framework to support projection

• Create the tragus using a composite graft (conchal cartilage from the opposite ear)
• Deepen the conchal bowl
• Refine any residual cosmetic defects

B. Nagata Two-Stage Technique (and Firmin Modifications)

• Harvest cartilage from ribs 6, 7, and 8 (more cartilage than Brent) to fashion a complete 3D framework including anthelix, antitragus, and tragus components
• Remove the remnant microtic cartilage
• Simultaneously transpose the lobule and create the tragus - procedures Brent performs as separate stages
• Insert the complex framework into a subcutaneous pocket

• A perihelical incision is advanced posteriorly; a posterior scalp flap is widely elevated (with care to avoid injury to hair follicles)
• An anteriorly based postauricular fascial flap is developed and brought down to cover a projecting cartilage block placed just posterior to the conchal bowl
• The posterior scalp flap is advanced to the neo-postauricular crease
• A full-thickness or split-thickness skin graft covers the posterior surface of the reconstructed ear

• A hemitransfixion incision to transpose the lobule without preserving a subcutaneous pedicle near the conchal bowl - this optimizes conchal definition while maintaining vascularity
• Employment of a posterior cartilage foundation to improve definition of the root of helix and tragus
• Firmin reports excellent aesthetic outcomes with this approach

2. ALLOPLASTIC RECONSTRUCTION - POROUS POLYETHYLENE (Medpor/SuPor)

• A large Y-shaped incision is made with the anteroposterior limb approximately 10 cm superior to the auricular remnant in the temporal scalp, with one arm extending down to the remnant
• Skin flaps are elevated and a subcutaneous pocket is created at the correct anatomical position
• The implant is measured, trimmed, and placed in the pocket
• A large temporoparietal fascia flap (TPFF) is elevated and brought down to cover the implant
• The superior one-third of the implant (which lacks skin coverage) is covered with a full-thickness skin graft from the contralateral postauricular area

• Can be performed at a younger age (from ~3 years)
• Single-stage procedure (reduces operative burden)
• Excellent projection and definition
• No donor site morbidity from rib harvest
• No pneumothorax risk

• Risk of extrusion (no autologous integration)
• Long-term durability data are limited
• The thinness and pliability of TPFF minimizes framework distortion but the vascular supply to skin graft must be meticulous
• Complications (graft exposure, skin breakdown) are more difficult to salvage than autologous failures

3. AURICULAR PROSTHESES

A. Adhesive-Retained Prostheses

• Silicone prosthetic ears affixed with medical adhesive glue (applied daily)
• Lifelike cosmesis with minimal surgical morbidity
• Limitations: requires daily care, skin reaction risk, prosthesis degradation over time

B. Bone-Anchored Auricular Prosthesis (BAAP)

• Titanium osseointegrated posts placed surgically in the mastoid bone
• The silicone prosthesis clips onto the posts
• Requires minimum calvarial bone thickness of 3-4 mm (usually age >5 years; FDA minimum age for implantation)
• Necessitates removal of the vestigial ear (including the lobule), which precludes subsequent autologous reconstruction
• A specialist prosthetist is critical for planning, prosthesis fabrication, and aftercare

• Lack of autogenous tissue
• Irradiated tissue (post-radiation fibrosis/ischemia makes flap reconstruction unreliable)
• Failed autologous reconstruction
• Cancer resection leaving large defects
• Absence of the lower half of the pinna
• Severe soft-tissue or skeletal hypoplasia
• Unfavorable hairline (would result in hair-bearing skin over framework)
• Patient preference

4. RECONSTRUCTION BY DEFECT TYPE

Grade I Microtia

• Often does not require reconstruction as it cannot be cosmetically improved
• If there is EAC atresia, atresia surgery can proceed without auricular reconstruction
• If prominent ears coexist, otoplasty (e.g., Mustarde technique) can be performed

Grade II Microtia

• Depends on the development of the residual auricle and surgeon expertise
• If residual cartilage is not salvageable, autologous rib cartilage reconstruction is performed from scratch
• Some cases can be addressed with a single-stage anterior incision approach

Grade III / Anotia

• Full autologous costochondral reconstruction (Brent or Nagata technique)
• OR Medpor alloplastic reconstruction
• OR BAAP prosthesis

Traumatic Defects

• Avulsed pinna with intact cartilaginous framework: cartilage preserved and "banked" in a postauricular scalp pocket; later used in reconstruction
• Partial defects: local flaps with or without cartilage grafts
• Total defects: as for Grade III microtia

5. COMPLICATIONS

6. PREOPERATIVE ASSESSMENT

• Unilateral vs. bilateral microtia
• Size and location of microtic ear; development of contralateral pinna
• Hairline assessment (unfavorable high or low hairline affects planning)
• Site and size of remnant lobule
• Presence of skin separating remnants (may indicate superficial facial nerve - caution required)
• Presence of stenotic ear canal
• Mastoid bone growth and space between TMJ and mastoid tip
• Facial asymmetry (hemifacial microsomia, Goldenhar syndrome)
• Facial nerve function

• Most microtia patients have conductive hearing loss from canal atresia
• Some have underlying SNHL - bone conduction thresholds essential
• Hearing rehabilitation (BCHA or BACD) addressed separately from cosmetic reconstruction

Key Surgical Principles (All Techniques)

1. Framework construction - anatomically accurate 3D cartilage framework is the foundation
2. Soft tissue cover - thin, pliable skin (non-hair-bearing) to allow framework definition to show
3. Projection - retroauricular sulcus creation to achieve natural ear projection
4. Autologous is preferred - lower infection, rejection, and extrusion risk compared to alloplastic
5. Meticulous suction drainage in Stage 1 ensures skin adherence to the framework
6. Staged approach reduces skin tension and vascular compromise at each stage