Microtia Classification and Symptoms
Microtia is not merely a cosmetic issue, its manifestations range widely from mild underdevelopment of the auricle to its complete absence. It is clinically classified into four grades:
Grade I: The auricle is smaller than normal, but key structures are visible. The ear canal may be narrow or affected by aural atresia.
Grade II: The auricle is partially developed, often hook-shaped or S-shaped. The ear canal is usually affected by aural atresia.
Grade III: Only a vertical remnant of tissue is present (often described as a “peanut” shape). The ear canal is completely affected by aural atresia.
Grade IV: Complete absence of the auricle, with no residual tissue (anotia).
Approximately 50-60% of microtia patients have associated ipsilateral facial underdevelopment, such as Hemifacial Microsomia. Bilateral microtia accounts for about 10-20% of all cases; these patients typically face more complex hearing challenges.
Treating microtia requires the involvement of a multidisciplinary medical team, including:
ENT (Otolaryngologist): Evaluates ear structure and hearing function.
Plastic Surgeon: Performs auricular reconstruction surgery.
Audiologist: Conducts hearing assessments (Audiometry) and provides rehabilitation guidance.
Speech Therapist: Assists with speech development training.
Psychologist/Therapist: Provides psychological support and counseling.
Microtia Diagnostic Process
Initial evaluation typically begins in infancy, including a detailed physical examination, hearing assessment (Audiometry), and imaging studies. Hearing tests may include Auditory Brainstem Response (ABR) and Otoacoustic Emissions (OAE) to determine the type and degree of hearing loss. Imaging studies such as CT scans help assess the middle and inner ear structures, providing crucial information for subsequent treatment planning.
Timing and Sequence of Microtia Treatment
Treating microtia is a long-term process, requiring planning based on the patient’s age and specific circumstances:
Infancy (0-3 years): The focus is on hearing management and language development. Children with bilateral microtia should begin using a bone conduction hearing device before 3 months of age. Unilateral cases require regular hearing monitoring. Early intervention is crucial for language development.
Preschool Age (4-6 years): Hearing management and speech therapy continue, while preparation for surgery begins. Discussing the treatment process with the child using pictures and models helps their understanding.
Optimal Surgical Age (6-10 years): By this age, the rib cartilage is sufficiently developed for grafting, and the auricle size is close to adult size. The child also has better psychological readiness and ability to cooperate. Treatment is divided into two main parts—auricular reconstruction and hearing reconstruction—which may be performed in stages based on patient needs.
Auricular Reconstruction
Primarily employs the following three methods:
Autologous Rib Cartilage Reconstruction: This method typically requires 2-4 stages.
Stage 1: An autologous rib cartilage graft is harvested, carved into a 3D ear framework, and implanted under the skin.
Stage 2 (6-12 months later): Lobule transposition and auricular elevation.
Stage 3: Tragus formation and detail refinement; possible adjustment of the contralateral ear for symmetry.
Advantages: Uses the patient’s own tissue, high stability, low infection risk, appearance becomes more natural over time.
Disadvantages: Multiple surgeries, chest wall scar, longer recovery.
Alloplastic Implant (e.g., Medpor Implant): Uses a synthetic framework.
Procedure: Typically requires 1-2 stages. The implant is placed and covered with a temporoparietal fascia flap, followed by skin grafting.
Advantages: Fewer surgeries, no rib cartilage harvest, no chest scar.
Disadvantages: Higher risk of infection and extrusion; stability may be lower than autologous grafts.
Prosthetic Ear: An option for patients unsuitable for or unwilling to undergo surgery.
Attachment: Can be adhered with medical adhesive or attached via osseointegrated implants.
Advantages: No surgery required, highly realistic appearance, removable.
Disadvantages: Requires daily removal and cleaning, periodic replacement, long-term cost.
Hearing Reconstruction
Most microtia patients have conductive hearing loss, often due to aural atresia. Hearing rehabilitation options include:
Canalplasty: Creates a new ear canal and reconstructs the eardrum and ossicular chain. Success rates vary, with a risk of restenosis.
Bone Conduction Hearing Devices: Traditional devices: Held by a headband or softband.
Bone-Anchored Hearing Aid (BAHA): A surgically implanted abutment connects to an external sound processor.
Softband devices: Suitable for infants/young children, no surgery required.
Middle Ear Implants: Such as the Vibrant Soundbridge, which directly stimulates the ossicles.
Postoperative Recovery and Long-Term Follow-up
Adequate recovery is needed after each procedure. Long-term follow-up includes annual assessment of the auricle’s appearance and stability, regular audiometry (hearing tests), and psychological support.
Expected Outcomes After Microtia Treatment
Improvements are expected in three key areas:
- Appearance: Outcomes vary based on the method chosen (autologous rib cartilage graft, Medpor implant, or prosthetic ear), each with distinct advantages and limitations regarding naturalness, feel, and maintenance.
- Hearing: Hearing can be partially improved with canalplasty or BAHA implantation, but typically not fully restored to normal levels.
- Psychological Impact:Improved appearance usually leads to significantly enhanced self-confidence and social engagement.
Future Perspectives and Emerging Technologies
The field of microtia treatment is continuously evolving. Research areas include tissue engineering (lab-grown cartilage), 3D printing for customized frameworks and surgical guides, and genetic studies on Microtia and Hemifacial Microsomia.
Conclusion: The treatment of Microtia is a journey requiring both patience and courage. However, with advancements in medical technology and the collaboration of multidisciplinary medical teams, patients can now achieve significant improvements in both appearance and functional recovery. It is crucial that treatment is tailored based on individual circumstances, family preferences, and professional medical advice to develop the most suitable personalized plan for each patient. For assistance, please contact ENT Head and Neck Surgery Centre (Tel: 3100 0555), where our ENT specialists will provide detailed diagnosis and formulate a treatment plan for you.
Source:
HK ENT Specialist Ltd.
ENT Head and Neck Surgery Centre
For ENT Services, Audiology & Speech Therapy,
Sleep Disordered Breathing Management,
Hearing Aid Prescription & Medical Cosmetic Services
https://www.hkentspecialist.hk
