Congenital maxillomandibular fusion (syngnathia) is rare. The first case was reported in 1936. By 2004, only 25 cases of syngnathia had been reported including 6 cases with fusion of the ascending rami of the mandible with the maxilla and zygomatic complex. This report concerns a 6-month-old girl with a type of congenital fusion of the ascending rami of the mandible with the upper alveolar arch and zygomatic complex that leads to restriction of mouth opening. The clinical features of this anomaly and a brief review of literature are presented.
Congenital craniofacial disorders represent approximately 20% of all birth defects and one of these disorders is maxillomandibular fusion . The first case was detected in 1936. By 2004, only 25 cases of syngnathia had been reported including six cases involving the zygomatic complex and mandible fusion . Congenital maxillomandibular fusion (syngnathia) is a rare deformity seen in infants that often appears as part of a syndrome and can vary in severity from single mucosal bands (synechiae) to complete bony fusion (synostosis), which is less common than synechiae. It may affect soft and/or hard tissue and can restrict maximum mouth opening causing problems with feeding and respiration .
A case report is presented of bony fusion of the mandible to the maxilla and zygomatic complex in a 6-month-old girl who was not able to open her mouth or feed normally.
A 6-month-old girl with a congenital facial deformity and inability to open her mouth since birth was referred. She was underfed and unable to thrive. There was no significant family history and no history of illness, trauma or medical therapy during pregnancy. Routine laboratory data were normal.
Physical examination revealed the child had an earlobe deformity. She had a large earlobe with prominent upper pole, symmetrical bilateral congenital auricular sinuses and small skin pits approximately 2 cm anterior to the tragus. She had bilateral abnormal lateral canthal fissure and as a result of syngnathia, the mandible was deviated to the right, and there was restricted jaw opening. Her mouth could only be opened 10–15 mm so she received tube feeding. Her lips, buccolabial vestibule and oral mucosa were normal ( Fig. 1 ).
After sedation, a facial CT scan in axial, coronal and three-dimensional spiral reconstruction views was taken. The right ascending rami and alveolar arch of the mandible were fused to the upper alveolar arch and zygomatic complex. The coronoid process and sigmoid notch were not determined. The temporomandibular joint (TMJ) and left side of the mandible were normal and there was no other associated abnormality in the facial bone formation ( Figs. 2 and 3 ).
After nasal intubation with a fine fibreoptic laryngoscope and general anaesthesia, to aid haemostasis in the areas of the planned soft tissue incisions and dissection, local anaesthesia with 1/200,000 epinephrine was injected. Exposure was obtained by an intraoral incision from the maxillary vestibule to the anterior border of the mandibular rami and vestibule ( Fig. 4 ). Osteotomy was carried out with a bur and osteotome, releasing the alveolar process and anterior rami of the mandible from the zygomatic complex and maxillary alveoli. The mucosal layers of the maxilla and mandible were sutured separately.
After surgery, some limitation in jaw opening remained, so the first tube feeding was carried out under close nursing supervision. The parents were trained how to open the jaw manually. After 1 month jaw opening had increased to 20–25 mm so tube feeding was no longer necessary.
Long-term follow-up was not possible because the child died 2 months after surgery. The cause of death was diagnosed as aspiration pneumonia.