From Fusion to Function: Clinical Insights and Therapeutic Strategies in Syngnathia.

Background: Syngnathia is a very rare craniofacial anomaly, referring to different forms of fusion of the upper and lower jaw, with or without involvement of the temporomandibular joint (TMJ). Due to its rarity, limited knowledge is available about the clinical manifestation and, in specific, about treatment strategies. The aim of the study is to map out the clinical manifestation and the currently used treatment options by collecting information systematically in a case series.

Methods: Within the European Reference Network of Craniofacial Anomalies and ENT disorders, a call was sent out to identify cases of syngnathia. In several meetings, a clinical checklist was developed and approved by all involved centers. Data was collected through the checklist, and a comparison with previous literature was made.

Results: A total of 12 cases of syngnathia were identified. Cases included bony and fibrous syngnathia, as well as a combination. The majority of the cases were diagnosed directly after birth. Most cases were associated with additional (craniofacial) anomalies and syndromes occurred in 4 of the cases. In 6 cases, the TMJ was involved. Treatment strategies varied and timing of the first surgery differed between 4 days and 9 years. In all cases, feeding problems occurred. The need for a tracheal stoma was reported in 8 cases.

Conclusion: This study presents the largest case series of syngnathia so far, emphasizing the high occurrence of oral health problems in the population. Suggestions for adjustment of a clinical classification system are made. Concerning treatment decisions, caution should be taken with early release operations.