Congenital fusion of the jaws: a management protocol

Abstract

Congenital fusion of the jaws is the inability to open the mouth at the time of birth. It occurs as a result of fusion of the jaws or fusion of the mandible to zygoma or temporal bone. The authors report four case studies and describe their management protocol.

Congenital fusion of the jaws is the inability to open the mouth at the time of birth. It occurs as a result of fusion of the jaws or fusion of the mandible to zygoma or temporal bone. Only a few cases have been reported in the literature. Terms that are commonly used in the literature related to this condition are synechiae , syngnathia and synostosis. Synechiae and synostosis are general terms describing the type of tissue involved in the fusion: soft and bony, respectively. Syngnathia is used when there is fusion between the maxilla and the mandible, which may be in the midline or laterally placed and may be unilateral or bilateral.

The combination of the deformities, their idiopathic nature and difficulties classifying them makes their management challenging. The management of these children is unclear. No proven methodology is described in the literature because of the variable presentation and because some patients have survived without treatment. The authors present their experience with a series of 4 cases of congenital fusion of the jaws, including a case of oromandibular limb hypogenesis syndrome . They also present their protocol for the management of these children.

Case reports

Case 1 ( Fig. 1 a–d)

A 9-month-old female baby born to non-consanguineous parents presented with an inability to open the mouth since birth and difficulty in feeding because of eruption of teeth. The prenatal history was uneventful and the child was born by spontaneous vaginal delivery. No records were available about the mother’s obstetric history or the child’s birth. The child was apparently healthy. The child had no developmental delay. Three dimensionally (3D) reconstructed CT scans showed fusion of maxilla and mandible on both sides and a normal temporomandibular joint (TMJ). Immediate surgery to release the fusion was not considered as the baby was thriving well. The parents were informed to report immediately in case of emergencies. At the age of 1 year the decision to operate was made as the child’s general condition had improved adequately. Routine haematological investigations were found to be normal. Surgery was planned under general anaesthesia as it was a bony fusion. The airway was secured using a fibreoptic endoscope and the surgery was uneventful. The surgery was performed through a bilateral submandibular approach, which was primarily a release of the fusion and the gap created was interposed with silastic sheet to prevent re-ankylosis. The child was reviewed at 10 days, 1 month and 6 months postoperatively. Mouth opening at the time of discharge was approximately 26 mm and remained the same during the first month of follow up. There was marginal decrease of mouth opening, nearly by 5 mm during the 6 months of follow up, after which the patient did not return for follow up.

Fig. 1
(a) Preoperative frontal view. (b) CT scan showing fusion between maxilla and mandible. (c) Intraoperative photograph showing maxillomandibular fusion. (d) 6 months follow up photograph showing good mouth opening.

Case 2 ( Fig. 2 a–c)

A 3-month-old male baby was referred with difficulty in mouth opening. He was the first child of his parents who were unrelated before marriage. No other relevant prenatal history could be elicited. Clinical examination revealed difficulty in opening the mouth, fusion of the maxilla and mandible on the right side with a lateral open bite on the left side. 3D reconstructed CT scans revealed a fusion at the TMJ region on both sides without a significant condyle and coronoid process. As the patient was doing well, surgery was delayed considering the risks involved. Although the child had a lateral open bite, feeding was difficult and a gastrostomy tube was placed under local anaesthesia. The patient was followed up. At 10 months of age the child underwent surgery as his general condition had improved. He had gained weight and his haemoglobin levels had improved. Routine blood investigations were within normal limits. The airway was secured by tracheostomy as fibreoptic endoscopy failed. Bilateral submandibular incisions were placed, the TMJ fusion was released and interposition was done with silastic. Intraorally there was no fusion though clinically it mimicked fusion. Postoperatively the baby was slowly weaned off the tracheostomy and gastrostomy tubes. His general condition improved and his mouth opening was good. Mouth opening at the time of discharge was approximately 25 mm. The mouth opening remained at 25 mm during his first month of follow up, but it decreased marginally to 22 mm and 20 mm during the 6 month and annual follow up.

Fig. 2
(a) Preoperative frontal view. (b) Baby with the feeding gastrostomy tube. (c) Intraoperative photograph showing fusion of the mandible to cranium.

Case 3 ( Fig. 3 a and b)

A 2-day-old male baby was referred because of difficulty opening his mouth. He was the first child of unrelated parents. Clinical examination showed an under developed mandible, six digits in the forearm, mild anterior open bite and no mouth opening. The lateral side of the maxilla and mandible on both sides were in close contact with each other and there was no evidence of a gap between them. Haematological investigations were within normal limits. A CT scan was planned for a later date. The patient was thriving so surgery has been postponed. The parents were instructed to report to the authors’ unit every month or in case of emergency.

Fig. 3
(a) Frontal view showing marked deficiency of the mandible and nasogastric tube. (b) Anomaly of the hand with six digits.

Case 4 ( Fig. 4 a and b)

A 2-day-old male baby with reductive limb deformities was referred with complaints of difficulty in feeding due to restricted mouth opening. The baby was the first child of unrelated parents and the mother had taken treatment for infertility. Details about the type of drug taken were not known. The baby’s complete blood count and haemoglobin levels were within normal limits. Clinical examination revealed fusion of the maxilla and mandible. The posterior portion of the maxilla and mandible could not be assessed. The baby had reductive limb deformities involving the upper and lower limbs. The baby died before surgery could be planned; the cause of death was septicemia following aspiration. A postmortem examination revealed a normal TMJ bilaterally and a bony fusion at the midline between the maxilla and mandible almost 1 cm wide. This case is probably an expression of the oromandibular limb hypogenesis syndrome.

Fig. 4
(a) Frontal view of the baby. (b) Photograph shows congenital amputation of the arms and legs.

Treatment protocol

The relative rarity of syngnathia and the limited knowledge about it has made the management challenging. No standard management protocol is available because of the rarity of the condition and the survival of a few patients without treatment . The authors use the following protocol.

Assessment of general condition

The need for surgery in these patients depends on their condition at the time of presentation. If the child can thrive without life-threatening complications, surgery can be delayed to avoid undue risks. Studies have shown that children less than 6 months old are more prone to critical events during anaesthesia such as cardiac arrest and airway problems. Cardiac arrests are related to medication, mainly halothane. The chances of encountering airway related problems, such as laryngospasm, should be borne in mind before administering anaesthesia for children less than 1 year of age . A literature review shows that only a few patients have undergone surgery on an emergency basis .

Feeding

The delay in surgery and the fused jaws make feeding difficult in some patients. The possible ways to feed such babies are by oral feeding through the existing open bite, a nasogastric tube or a gastrostomy tube. Oral feeding is the only one that is relatively risk free. Prolonged use of a nasogastric tube should be avoided because it carries the risk of esophageal cardiac sphincter incompetence and aspiration pneumonitis . Feeding by gastrostomy tube also has complications.

Radiographs

Conventional radiographs are of limited value in determining the site and type of fusion, but must be taken for a generalized assay. The availability of 3D reconstructed CT scans gives a clear picture of the fusion and aids in planning surgery.

Planning surgery

The goal of surgery is to relieve trismus and prevent recurrence. Clinical examination of the patient under anaesthesia confirms the radiographic findings and gives information about the soft tissue structures of the oral cavity. The suppleness of the buccal mucosa plays an important role in the outcome and postoperative rehabilitation. Mucosal fibrosis of the cheek prevents mouth opening and needs to be excised to improve it. The raw area thus created will lead to future relapse during healing. Surgical planning to address the raw area must be borne in mind.

Surgical exposure depends on the site of fusion. Both preauricular and submandibular incisions have been used. Preauricular incisions may be preferred for fusions related to the TMJ region. The authors used a submandibular incision though they had one case with TMJ fusion. Osteotomy of the fusion can be performed easily with the help of 3D CT scanning. Recurrence can be prevented by interposing silicone sheets or blocks and by interposing gauze packs for intraoral raw areas .

Airway

Blind nasal intubation, fibreoptic intubation and tracheostomy are the common ways of securing the airway. There are fewer risks with fibreoptic intubation than with other techniques. Blind nasal intubation caries the risk of laryngeal edema and its sequelae . Tracheostomy should be the last resort because of the postoperative complications .

Physiotherapy

Soft rubber can be used as a wedge for mouth opening. Periodic jaw opening exercises can be carried out by the patient’s parents. Most cases required second corrective surgery because of recurrence, due to the difficulty in giving physiotherapy for such small babies. The literature review shows that the frequency of recurrence is higher in syndromal rather than non-syndromal cases, but the raeson is not known.

Follow up

Periodic recall is important to assess the progress of the child’s growth. The parents must be educated about the need for follow up and future surgical intervention. The maximum period of follow up is only up to 3 years . Long-term follow up is needed to assess the complete growth pattern in such patients.

Treatment protocol

The relative rarity of syngnathia and the limited knowledge about it has made the management challenging. No standard management protocol is available because of the rarity of the condition and the survival of a few patients without treatment . The authors use the following protocol.

Assessment of general condition

The need for surgery in these patients depends on their condition at the time of presentation. If the child can thrive without life-threatening complications, surgery can be delayed to avoid undue risks. Studies have shown that children less than 6 months old are more prone to critical events during anaesthesia such as cardiac arrest and airway problems. Cardiac arrests are related to medication, mainly halothane. The chances of encountering airway related problems, such as laryngospasm, should be borne in mind before administering anaesthesia for children less than 1 year of age . A literature review shows that only a few patients have undergone surgery on an emergency basis .

Feeding

The delay in surgery and the fused jaws make feeding difficult in some patients. The possible ways to feed such babies are by oral feeding through the existing open bite, a nasogastric tube or a gastrostomy tube. Oral feeding is the only one that is relatively risk free. Prolonged use of a nasogastric tube should be avoided because it carries the risk of esophageal cardiac sphincter incompetence and aspiration pneumonitis . Feeding by gastrostomy tube also has complications.

Radiographs

Conventional radiographs are of limited value in determining the site and type of fusion, but must be taken for a generalized assay. The availability of 3D reconstructed CT scans gives a clear picture of the fusion and aids in planning surgery.

Planning surgery

The goal of surgery is to relieve trismus and prevent recurrence. Clinical examination of the patient under anaesthesia confirms the radiographic findings and gives information about the soft tissue structures of the oral cavity. The suppleness of the buccal mucosa plays an important role in the outcome and postoperative rehabilitation. Mucosal fibrosis of the cheek prevents mouth opening and needs to be excised to improve it. The raw area thus created will lead to future relapse during healing. Surgical planning to address the raw area must be borne in mind.

Surgical exposure depends on the site of fusion. Both preauricular and submandibular incisions have been used. Preauricular incisions may be preferred for fusions related to the TMJ region. The authors used a submandibular incision though they had one case with TMJ fusion. Osteotomy of the fusion can be performed easily with the help of 3D CT scanning. Recurrence can be prevented by interposing silicone sheets or blocks and by interposing gauze packs for intraoral raw areas .

Airway

Blind nasal intubation, fibreoptic intubation and tracheostomy are the common ways of securing the airway. There are fewer risks with fibreoptic intubation than with other techniques. Blind nasal intubation caries the risk of laryngeal edema and its sequelae . Tracheostomy should be the last resort because of the postoperative complications .

Physiotherapy

Soft rubber can be used as a wedge for mouth opening. Periodic jaw opening exercises can be carried out by the patient’s parents. Most cases required second corrective surgery because of recurrence, due to the difficulty in giving physiotherapy for such small babies. The literature review shows that the frequency of recurrence is higher in syndromal rather than non-syndromal cases, but the raeson is not known.

Follow up

Periodic recall is important to assess the progress of the child’s growth. The parents must be educated about the need for follow up and future surgical intervention. The maximum period of follow up is only up to 3 years . Long-term follow up is needed to assess the complete growth pattern in such patients.

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Feb 8, 2018 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Congenital fusion of the jaws: a management protocol
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