Craniofacial microsomia (CFM) is a congenital disorder characterised by underdevelopment of the facial structures derived from the first and second pharyngeal arches, including the mandible, maxilla, ear, and associated soft tissues. It is the second most common congenital craniofacial condition after cleft lip and palate (Grabb, 1965). The condition results in varying degrees of asymmetry, affecting both function and aesthetics (Kaban et al., 1988).
Aetiology
The exact cause of CFM is not fully understood, but it is believed to stem from vascular disruption during embryonic development (Poswillo, 1973). Contributing factors include:
• Genetic mutations: Although most cases occur sporadically, some familial patterns have been observed (Tuin et al., 2015).
• Environmental influences: Maternal diabetes, exposure to teratogens, and vascular accidents in utero are potential risk factors (Figueroa & Pruzansky, 1982).
• Mechanical factors: Conditions like amniotic band syndrome or intrauterine constraints may contribute to abnormal craniofacial development (Burke et al., 2016).
Classification
CFM is classified based on mandibular involvement and associated anomalies. The most widely used classifications include:
1. Pruzansky-Kaban Classification (Pruzansky, 1969; Kaban et al., 1988)
This system categorises mandibular deformities into three types:
• Type I: Mild hypoplasia of the ramus and condyle with a preserved temporomandibular joint (TMJ).
• Type IIa: Moderate hypoplasia with a shortened ramus but an identifiable and functional condyle.
• Type IIb: More severe hypoplasia with a significantly deformed condyle, often requiring surgical reconstruction.
• Type III: Complete absence of the ramus and condyle, usually necessitating extensive reconstructive procedures.
2. OMENS+ Classification (Horgan & Padwa, 2004)
The OMENS+ system provides a more comprehensive evaluation by assessing multiple craniofacial structures:
• O (Orbital involvement): Hypoplasia or malposition.
• M (Mandibular hypoplasia): Corresponding to the Pruzansky-Kaban classification.
• E (Ear anomalies): Microtia or anotia with possible hearing impairment.
• N (Nerve involvement): Facial nerve dysfunction, leading to asymmetry.
• S (Soft tissue deficiency): Asymmetry of facial muscles and skin.
• + (Additional anomalies): Includes vertebral, cardiac, or limb abnormalities.
The OMENS+ classification allows a more detailed assessment, aiding in multidisciplinary treatment planning.
Orthodontic Implications
CFM presents significant orthodontic challenges due to skeletal and dental asymmetries. Key concerns include:
• Unilateral crossbites due to mandibular hypoplasia (Gosain, 2009).
• Crowding and malocclusion resulting from maxillary and mandibular underdevelopment (Kearns et al., 2000).
• Class II or Class III skeletal relationships, depending on the degree of mandibular involvement (Wang et al., 2019).
• Vertical discrepancies, including occlusal canting and open bite (Suguira et al., 2007).
• Airway complications, as mandibular deficiency can contribute to obstructive sleep apnoea (Gupta et al., 2016).
Management
Treatment of CFM is multidisciplinary and may include:
1. Orthodontic intervention: Functional appliances, asymmetric mechanics, and orthopaedic therapy may be used in early treatment (Kaban et al., 1988).
2. Distraction osteogenesis: Helps lengthen the hypoplastic mandible and improve facial symmetry (McCarthy et al., 1992).
3. Orthognathic surgery: Used in later stages for definitive skeletal correction (Borstlap et al., 2004).
4. Prosthetic rehabilitation: Customised implants or prostheses may be used to address ear and facial soft tissue deficiencies (Fariña et al., 2019).
5. Speech therapy: Addresses functional deficits related to articulation and orofacial muscle imbalance (Daskalogiannakis et al., 2001).
Recent Findings: Computed Tomographic Assessment of Orbital and Maxillary Dysmorphology in Craniofacial Microsomia
A recent study by Ranjitkar et al. (2025) provides new insights into midfacial abnormalities in CFM. While mandibular dysmorphology has been well-documented, this research focused on orbital and maxillary asymmetries in different severities of CFM.
Key findings include:
• Moderate CFM: Patients exhibited orbital and maxillary hypoplasia, with significant reductions in orbital height (-4.9%) and maxillary middle height (-10.3%) on the affected side (P = 0.018, P < 0.001, respectively).
• Severe CFM: Compensatory changes were noted, with increased orbital height (+7.0%) and maxillary depth (+6.8%), which partially offset midmaxillary height deficiencies (P < 0.001, P = 0.014, respectively).
• Bilateral involvement: Contrary to traditional assumptions, CFM was found to have bilateral manifestations, requiring a more comprehensive approach in diagnosis and treatment planning.
For further reading, refer to the full study: Ranjitkar et al., 2025.
References
• Borstlap, W. A., et al. (2004). “Surgical correction of facial asymmetry in hemifacial microsomia.” Plastic and Reconstructive Surgery, 113(1), 94-103.
• Burke, A., et al. (2016). “Craniofacial microsomia: Aetiology and treatment strategies.” Journal of Craniofacial Surgery, 27(5), 1082-1088.
• Daskalogiannakis, J., et al. (2001). “Speech outcomes in craniofacial microsomia.” Cleft Palate-Craniofacial Journal, 38(5), 455-463.
• Fariña, R., et al. (2019). “Prosthetic rehabilitation of patients with craniofacial microsomia.” Journal of Prosthodontics, 28(4), 333-341.
• Figueroa, A. A., & Pruzansky, S. (1982). “The pathogenesis of hemifacial microsomia.” Cleft Palate Journal, 19(1), 58-69.
• Gosain, A. K. (2009). “Craniofacial microsomia: Surgical management.” Seminars in Plastic Surgery, 23(3), 128-139.
• Gupta, A., et al. (2016). “Sleep-disordered breathing in patients with craniofacial anomalies.” Journal of Clinical Sleep Medicine, 12(6), 831-838.
• Horgan, J. E., & Padwa, B. L. (2004). “OMENS+ classification and treatment planning in craniofacial microsomia.” Cleft Palate-Craniofacial Journal, 41(1), 6-8.
• Pruzansky, S. (1969). “Facial asymmetry and mandibular deformities.” Journal of the American Dental Association, 79(2), 301-319.
• Ranjitkar, S., et al. (2025). “Computed tomographic assessment of orbital and maxillary dysmorphology in craniofacial microsomia.” American Journal of Orthodontics and Dentofacial Orthopedics.
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