Temperomandibular joint ankylosis in children.

Temperomandibular joint (TMJ) ankylosis or hypo mobility involves fusion of the mandibular condyle to the base of the skull. Impairment of speech, difficulty in mastication, poor oral hygiene, rampant caries, and acute compromise of the airway pose a severe psychological burden on the tender minds of children. The treatment of TMJ ankylosis poses a significant challenge because of technical difficulties and a high incidence of recurrence. This report describes a case of 7-year-old with inability to open mouth, diagnosed with unilateral right bony TMJ ankylosis. The surgical approach consisted of inter-positional arthroplasty followed by physiotherapy. A detailed history, clinical and functional examination, and radiographic examination facilitating correct diagnosis followed by immediate surgical intervention and physiotherapy can help us to restore physical, psychological and emotional health of the child patient.

Ankylosis of the temporomandibular joint (TMJ) is an intracapsular union of the disc-condyle complex to the temporal articular surface that restricts mandibular movements, including the fibrous adhesions or bony fusion between condyle, disc, glenoid fossa, and eminence. It is a serious and disabling condition that may cause problems in mastication, digestion, speech, appearance, and hygiene.

Temperomandibular joint ankylosis is most commonly associated with trauma (13-100%), local or systemic infection (10-49%), or systemic disease (10%), such as ankylosing spondylitis, rheumatoid arthritis, and psoriasis. Ankylosis can also occur as a result of TMJ surgery.[1]

Temperomandibular joint ankylosis requires surgery to restore mouth opening. Inability to open the mouth results in an inability to maintain dental hygiene and to chew solid food. This leads to dental caries, malocclusion, weight loss and stunned growth. The problems in TMJ ankylosis surgery are general anesthesia and the requirement for nasal intubation. In the absence of visualization of the vocal cords, it is difficult to intubate and often, tracheostomy is required.[2]

Case Report

A 10-year-old boy reported with the complaint of inability to open mouth since 1 year. History revealed that he had a fall from the bicycle and got injury on the face and back of his head 2 years back. No bleeding from mouth or face was noted at the time of injury. Parents recognized the inability to open mouth after sometime and child was then taken to a local doctor. The child was referred to Department of Pedodontics and Preventive Dentistry, Rama Dental College, Hospital and Research Center, Kanpur, for further evaluation and treatment planning. Extra oral examination revealed facial asymmetry with fullness of cheek on the right side [Figure 1]. The child showed almost nil mouth opening [Figure 2]. Radiographic examinations comprised of orthopantomogram [Figure 3] and computerized tomography that revealed a lack of structural organization and obliteration of right TMJ space. Based on these findings, a diagnosis of unilateral right bony TMJ ankylosis was confirmed.

Figure 1

Extraoral photograph

Figure 2

Preoperative mouth opening

Figure 3

Preoperative osteoprotegerin

Treatment

A sequential protocol for the treatment of TMJ ankylosis is based on aggressive resection of ankylotic mass. While resecting a special approach has to be directed particularly from the medial aspect of the joint which is in close proximity with internal maxillary artery to ensure that bony, fibrous and granulation tissues are completely removed.

After complete evaluation, a unilateral TMJ arthroplasty with interposing temporalis muscle graft was done under general anesthesia. The patient was intubated using a fiber-optic microscope, which is the recent technique of choice in patients who present with trismus. A Popowich modification of Alkayat and Bramley preauricular incision was employed. Full thickness mucoperiosteal flap was reflected, and the ankylotic mass was exposed [Figures 4 and 5]. After exposing the joint space, an arthrotomy cut was given at the level of the sigmoid notch.

Figure 4

Reflected full thickness of mucoperiosteal flap

Figure 5

Surgical exposure of ankylotic mass

The section consisted of two horizontal osteotomy cuts, which were placed at the level of joint (below the zygomatic arch) and removal of a bony wedge was done so that a gap is created between the roof of the glenoid fossa and ramus [Figure 6]. The bone was removed carefully by using surgical burs until the bone is thinned and then removed using chisel or osteotome.

Figure 6

Two horizontal osteotomy cuts placed

The joint cavity was then irrigated with betadine, and the bony margins were smoothened using bone file. A temporalis graft was harvested and sutured to the medial pterygoid muscle to act as an interposing sling [Figures 7 and 8].

Figure 7

Temporalis sling being harvested

Figure 8

Temporalis fibres being sutured to medial pterygoid

Postoperative course

Active mouth opening exercises are started immediately after postoperative pain subsides. However, for patients who have undergone International Monetary Fund, exercises are started soon after release of fixation. Patients are encouraged to start gentle, active and gradually increasing mouth opening exercises using their own fingers as a monitor to start with, in order to gain self-confidence, and they are allowed to take a soft diet. Wooden tongue blades are used thereafter with a gradually increasing number according to the patient's tolerance, avoiding any passive force or pain. This is performed under strict supervision for 15 min 5 times a day. Regular weekly visits are arranged during the 1st month, biweekly for the next 3 months, then monthly for 1 year [Figure 9]. The child regained her beaming smile and relishing her favorite foods with enthusiasm.

Figure 9

Postoperative mouth opening

Discussion

The clinical findings of TMJ ankylosis in children are affected by the age of onset, the duration, and whether the ankylosis is unilateral or bilateral. Unilateral ankylosis reveals unilateral hypoplasia of the mandible and deviation of the chin to the affected side.

Bilateral ankylosis results in severe retrognathia, mandibular alveolar protrusion, open-bite deformity, bird-face appearance, and hypertrophic and thick coronoid process. Night snoring and obstructive sleep apnea are the other clinical findings in bilateral ankylosis.[3]

Mandibular asymmetry or bird-face deformities will be the outcome according to whether the case is unilateral or bilateral. The long standing ankylosed joints result in chronic isometric contractions of the masticatory muscles. This gives rise to shortening of the mandibular ramus/rami (pterygomassetric muscle sling) recession of the chin and its elongation in a cephalocaudal direction and the development of the antegonial notch owing to the antagonistic actions of the pterygomassetric sling and the depressor muscles.[4]

Temperomandibular joint ankylosis protocols throughout the world suggest early surgical intervention, elaborate resection, early mobilization, and aggressive physiotherapy for at least 6 months posyoperatively.[5]

On the surgical front, our team comprised of three pediatric dentists, an oral and maxillofacial surgeon and pediatric anesthetist. TMJ arthroplasty followed by temporalis muscle interposing was planned.

A temporalis sling was used as it is the technique of choice for lining the glenoid fossa and is a good interposing material to permit adaptive growth in children.[67]

Temperomandibular joint ankylosis, not only hinders the integrity of the cranio-facial skeleton, but also affects the normal growth and development of jaws and occlusion.[8]

Every pediatric dentist, or every dentist who treats children is in a unique position to help such patients psychologically as well as physically.[9]