Hemifacial Microsomia Review: Recent Advancements in Understanding the Disease

Abstract

Hemifacial microsomia (HFM) is the second most common congenital disability of the face, with a prevalence of 1 in 3000 to 5600 live births. Although etiology is still not fully understood, including both genetics and environmental factors, the latest reports indicate the prominence of premature loss of the neural crest cells. What is more, a deficit of muscles of mastication, except the masseter, correlates in the pathomechanism of mandibular underdevelopment. Due to the significant phenotypic diversification, the typical picture of HFM cannot be determined. It may present as an esthetic concern—minor asymmetry with deformed auricle, and on the contrary, as microtia/anotia with conductive type hearing loss, hypoplastic mandible, and microphthalmia, impairing patient's daily activities. Referring to psychosocial problems, it has been proved that in population with HFM, there is a modestly elevated risk for behavior problems, social competence, and less acceptance. Over the years, more comprehensive methods of assessing the extent and severity of the HFM as the OMENS (+) classification have emerged. The authors like to summarize and present for plastic surgery resident and plastic surgeons the critical features of HFM, including the epidemiology, clinical presentation, pathogenesis, and innovative management reported in the current literature.

A homozygous missense variant in laminin subunit beta 1 as candidate causal mutation of hemifacial microsomia in Romagnola cattle

“…In humans, 50% of microtia cases are associated with ancillary findings, mostly craniofacial anomalies. 24 , 25 Hemifacial microsomia is 1 of the major microtia‐related diagnoses in human medicine with an incidence of 1:5600 live births 26 and is estimated as the most common birth defect of the human face, after cleft lip and cleft palate. Features of HFM include unilaterally as well as bilaterally deformity of the external ear and small ipsilateral half of the face with epibulbar dermoid and vertebral anomalies (OMIM 164210), leading to asymmetrical appearance.…”

“… 27 Due to a marked phenotypic diversification, no typical clinical picture can be assigned to HFM: it might present from minor asymmetry with deformed auricle or microtia, until complete anotia, with conductive type hearing loss. 24 …”

A narrative review of craniofacial deformities

“…It is also important to correct the ear deformities in HFM patients. Costochondral grafts can establish the cartilage framework and local flaps and can form the soft tissue coverage (76).…”

STING inhibition accelerates the bone healing process while enhancing type H vessel formation

“…In craniomaxillofacial surgery, distraction osteogenesis is frequently used in hemifacial microsomia for treating mandibular hypoplasia. 1 Bone healing process usually starts with an inflammatory response, which includes the recruitment of inflammatory cells and their secreted factors from the circulation to the healing site. [2][3][4][5] Innate immune cells, such as macrophages, have an integral role in bone repair.…”