Reconstruction of Congenital Arhinia With Stereolithographic Modeling: Case Correlate and Literature Review

Nasal Construction in Congenital Arhinia Due to Novel SMCHD1 Gene Variant

Arhinia, or congenital absence of the nose, is an exceedingly rare anomaly caused by pathogenic variants in the gene SMCHD1 . Arhinia exhibits unique reconstructive challenges, as the midface is deficient in skeletal and soft tissue structures. The authors present 2 related patients with arhinia who harbor a novel SMCHD1 gene variant and illustrate their surgical midface and nasal construction. Targeted sequencing was carried out on DNA samples from the 2 affected patients, 1 anosmic and 1 healthy parent, to identify variants in exons 3 to 13 of SMCHD1 . The affected patients and anosmic parent were found to have a novel SMCHD1 gene variant p.E473V. A staged surgical approach was applied. First, both patients underwent a LeFort II osteotomy and distraction osteogenesis to improve the projection of the midfacial segment, followed by tissue expansion of the forehead, and nasal construction with a forehead flap that was placed over a costochondral framework derived from rib cartilage. The novel gene variant could guide future investigations on genetic pathways and molecular processes that underly the physiological and pathologic development of the nose. Further investigations on the variable expressivity ranging from anosmia to arhinia could improve clinical genetic screens for risk stratification of individuals with anosmia on passing on arhinia to their children. Due to the exceptional rarity and complexity of congenital arhinia, most surgical approaches are developed on a single-case basis. This case series, albeit limited to 2 cases, is the largest pedigree of such cases in the literature. It highlights key principles of a staged approach to nasal construction in arhinia and discusses nuances and improvements learned between both patients. It subsequently offers an optimized guide to this surgical strategy.

[Manufacture of facial prosthesis by three-dimensional printing]

The objective of the literature review was to study and analyze literature sources on the methods and means of facial prosthesis manufacture by three-dimensional printing.

MATERIALS AND METHODS

An analysis of information sources covering the last 15 years was carried out, in search sources as PubMed, Elsiver and eLIBRARY and on the website of the Federal Institute of Industrial Property.

RESULTS

The technology of direct production of prostheses by volumetric printing from silicone materials is the object of research for its development. Most of the materials used for the manufacture of facial prostheses using 3D printing need technical improvements, often requiring expensive equipment, which in turn does not allow the method of manufacturing face prostheses by direct method in everyday clinical practice.

CONCLUSION

Based on the obtained data there is a need to develop a new structural material for the manufacture of facial prostheses by 3D printing using laser stereolithography and digital LED projection technologies.

Two Forehead Flaps for Nasal Reconstruction of a Patient with Arhinia

Complete or total arhinia, in which nasal soft tissue is absent, is an extremely rare disease. The embryological origin of the defect is thought to be the maldevelopment of paired nasal placodes. In this article, we introduce nasal reconstruction with two forehead flaps. The reconstruction was done with two forehead flaps in a 20-year-old male patient with arhinia. Using one frontal flap of the forehead as the inner layer and the other one as the outer layer. The postoperative care was uneventful. He was able to breathe through the nose. No chest pain or any difficulty was mentioned in daily activities. The principal advantage of this technique over previous techniques is that the operation is performed in two stages and at the end of the procedure the patient has the final shape of the nose and is able to breathe normally. Furthermore, this technique could be performed for all age groups.

A Clinical Report of the Complete Nasal Agenesis: Reconstruction of Congenital Arhinia and Review of the Literature

Congenital absence of the nose or arhinia is an exceptionally rare craniofacial malformation, and the pathophysiology of the arhinia is still unknown. Most arhinia patients can have difficulties with breathing and feeding due to the absence of the nose, nasal cavities, and associated problems. A 38-day-old female patient was referred to our clinic with arhinia. Physical examination revealed the complete agenesis of nasal structures as the nasal bones and vestibulum nasi. The region of the absent nose was flat and firm at palpation. Congenital arhinia may occur with other associated malformations such as ocular, ear, palate, and gonadal. Therefore, it is recommended to evaluate computed tomography/magnetic resonance imaging in the postnatal period. Additionally, a radiological evaluation will help nasal reconstruction by documenting changes in nasal and maxillary anatomy over time. Due to the limited number of arhinia cases presented, the surgical management of this condition has not been standardized. We presented the pyramid-shaped cartilage grafts for the nasal framework and an expanded paramedian forehead flap for the skin coverage for reconstruction of arhinia.