OMFS-0224Developmental anomaliesReconstructionadvancedRight mandibular ramus, condyle and external ear

Facial asymmetry with a small ear and deficient ramus

11-year-old female

Draft — educational study aid, pending faculty review.

§Chief complaint

One side of the face is smaller with a malformed ear

§Medical & dental history

01No cardiac or vertebral anomalies on screening
02Normal developmental milestones
03Occlusal cant with the maxilla following the short right ramus

§Clinical examination

01Right facial hypoplasia with chin deviated to the right and an occlusal cant
02Microtia grade II on the right with conductive hearing loss
03Short right ramus with a hypoplastic condyle; mouth opening 42 mm with deviation right
04Facial nerve function intact; no macrostomia

§ figuresFigures (3)

Hemifacial Microsomia — clinical image: Bialateral (both sides) hemifacial microsomia in an adolescent — Fig. 1Bialateral (both sides) hemifacial microsomia in an adolescent
“Bialateral hemifacial microsomia” · Purplepong · Public domain · Wikimedia Commons

Hemifacial Microsomia — clinical image: Treatment of a Pruzanski type I case of hemifacial microsomia, which has been achieved with distraction osteogenesis of the right side of the mandible, followed by maxillary osteotomy. Photos of the patient: a) before an — Fig. 2Treatment of a Pruzanski type I case of hemifacial microsomia, which has been achieved with distraction osteogenesis of the right side of the mandible, followed by maxillary osteotomy. Photos of the patient: a) before an
“Treatment of a Pruzanski type I hemifacial microsomia” · Καρακάση, Δ.Θ. και Λαζαρίδη, Ν.Θ. · CC BY-SA 4.0 · Wikimedia Commons

Fig. 3A girl suffering from Pruzanksky type III hemifacial microsomia of the right side: a) and b) face and profile view, demonstrate the asymmetry c) intraoral view shows the turn of the lower dental arch to the right, d) the

“Hemifacial microsomia Pruzansky type III” · Dithkar · CC BY 3.0 · Wikimedia Commons

Verified open-access images only, reproduced for education under their stated licences · no AI-generated or illustrative artwork · Hemifacial Microsomia figures pending faculty review.

§Differential diagnosis

Hemifacial microsomia (craniofacial microsomia)Unilateral mandibular and ear hypoplasia

Goldenhar syndromeAdds epibulbar dermoids and vertebral anomalies

Treacher Collins syndromeBilateral and symmetrical, downslanting palpebral fissures, coloboma

Condylar growth arrest post-traumaNormal ear, clear injury history

§Final diagnosis

Right hemifacial microsomia, Pruzansky-Kaban type IIA with grade II microtia

Unilateral hypoplasia of the mandibular ramus and condyle with an abnormal but present glenoid articulation, combined with ear anomaly, matches type IIA disease; a functioning if small condyle allows distraction osteogenesis rather than costochondral grafting.

§Investigations

01CT with 3D reconstruction to classify the ramus-condyle unit
02Audiological assessment and ENT referral
03Cephalometric analysis, photographs and study models
04Spine and renal screening to exclude an oculo-auriculo-vertebral spectrum

§Radiology

013D CT — short right ramus with a hypoplastic but articulating condyle; glenoid fossa shallow
02OPG — ramus height deficit 14 mm compared with the left
03Cephalogram — occlusal cant of 7 degrees

§Treatment plan

01Orthodontic preparation and monitoring of growth
02Mandibular distraction osteogenesis of the right ramus to lengthen and level the occlusion
03Auricular reconstruction with the ENT and plastic surgery team
04Definitive orthognathic surgery at skeletal maturity if residual asymmetry remains

§Surgical procedure

01Right ramus corticotomy with a uni-directional distractor via a retromandibular approach
02Latency 5 days, distraction 1 mm per day for 14 days, consolidation 12 weeks
03Orthodontic elastics guide occlusal levelling during distraction

§Follow-up & outcome

01Weekly review during the distraction phase
0212 weeks — device removed, ramus lengthened 14 mm, cant corrected
03Annual growth review to skeletal maturity

Outcome: Occlusal cant corrected and facial symmetry markedly improved; auricular reconstruction staged for age 13.

§Discussion

01Hemifacial microsomia is the second most common congenital facial anomaly after cleft lip and palate.
02Distraction osteogenesis generates bone and expands the soft tissue envelope simultaneously, which grafting cannot do.
03Relapse and continued asymmetric growth mean many patients still need orthognathic surgery at maturity.

§Clinical pearls / learning points

01Classify the ramus-condyle unit first — the Pruzansky-Kaban type determines the operation.
02Screen for vertebral, renal and cardiac anomalies in the oculo-auriculo-vertebral spectrum.

§Viva questions

What does the Pruzansky-Kaban classification describe?

The severity of mandibular ramus and condyle hypoplasia, from type I (small but normally shaped) to type III (absent ramus and condyle).

Which embryological structures are affected?

The first and second branchial arches.

§MCQs

Q1Hemifacial microsomia arises from maldevelopment of:

Q2Typical distraction rate in mandibular distraction osteogenesis is:

§ evidenceReferences & Evidence

Current Classification

WHO Classification of Tumours Online — Head and Neck

IARC / WHO · 2022

Continuously updated online edition of the WHO head and neck tumour classification.

View official source

Evidence summary

Highest level of evidence linked to this page: WHO / Official Classification.

L1 · Classification — 1
L6 · Textbook — 3

1 linked source was published from 2024 onwards. Where guidance is limited or contested, rely on the higher-level sources above rather than this summary. Educational use only — not a substitute for clinical judgement.

Content last reviewed

September 2026

Evidence last reviewed

September 2026

Next scheduled review

September 2027

Review status

EVIDENCE REVIEWED

Search latest PubMed evidence

Last literature search: 7 September 2026

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Current Classification