No abstract

Objective: Few epidemiological studies have investigated the external ear malformations anotia and microtia. The authors’ study aimed to investigate the relationships between age, sex, type of microtia, and birth place and associated malformation as seen in 1 private Japanese clinic. Methods: Cases of anotia/microtia that presented in Nagata Microtia and Reconstructive Plastic Surgery Clinic (Saitama, Japan) between 2005 and 2018 were included in the study. The authors identified 1896 patients with anotia/microtia with or without associated malformation. Most were primary cases, with some secondary reconstruction cases wherein the primary surgery was performed at another hospital. Cases were classified with Nagata classification; lobule type, small concha type, concha type, and anotia. Cryptotia was also observed in this study. Results: Among the patients, 61.1% were male, 85.4% had unilateral defects (69.0% LB), and 59.1% had a right-sided defect. Most patients were less than 1 year old (15.0%) or 8 to 10 years old (5.5%–6.3%) on first examination, while 58% were from the Kanto region, including Tokyo. Regarding concomitant disorders, 32.7% had an accompanying malformation, while 13.3% had associated syndromes (eg, craniofacial microsomia, Treacher Collins syndrome). To conclude, in the authors’ clinic, most cases of anotia/microtia were LB, unilateral, and seen in male patients. Information regarding several characteristic clinical features was obtained, especially that clefts and musculoskeletal deformities of the skull/face and jaw were the main accompanying malformations.

Craniofacial sutures are bone growth fronts that respond and adapt to biomechanical environments. Little is known of the role sutures play in regulating the skull biomechanical environment during patency and fusion conditions, especially how delayed or premature suture fusion will impact skull biomechanics. Tgf-β3 has been shown to prevent or delay suture fusion over the short term in rat skulls, yet the long-term patency or its consequences in treated sutures is not known. It was therefore hypothesized that Tgf-β3 had a long-term impact to prevent suture fusion and thus alter the skull biomechanics. In this study, collagen gels containing 3 ng Tgf-β3 were surgically placed superficial to the posterior interfrontal suture and deep to the periosteum in postnatal day 9 (P9) rats. At P9, P24, and P70, biting forces and strains over left parietal bone, posterior interfrontal suture, and sagittal suture were measured with masticatory muscles bilaterally stimulated, after which the rats were sacrificed and suture patency analyzed histologically. Results demonstrated that Tgf-β3 treated sutures showed less fusion over time than control groups, and strain patterns in the skulls of the Tgf-β3 treated group were different from that of the control group. While bite force increased with age, no alterations in bite force were attributable to Tgf-β3 treatment. These findings suggest that the continued presence of patent sutures can affect strain patterns, perhaps when higher bite forces are present as in adult animals.