Modified coronoid process grafts combined with sagittal split osteotomy for treatment of bilateral tmj ankylosis
INDIAN DENTAL ACADEMY
Leader in continuing dental education
PROCESS GRAFTS COMBINED
WITH SAGITTAL SPLIT
TREATMENT OF BILATERAL
HONG YONGLONG et al.,XIAN,
• Tmj ankylosis leads to restriction of oral opening ranging from partial
reductioon to complete immobility of the jaw.
• The most common cause is the macrotrauma associated with a condylar
process # during the active growth period in childhood.
• Commonly used tech’s such as gap arhroplasty at different levels,
interpositional cartilage grafts, and arthroplasty.
• Recently to improve both function and profile, an arthroplasty combined
with orthognathic surgery has been recomended
PATIENTS AND METHODS
• Six pts with bilateral tmj ankylosis and severe retrognathia were treated during the
period june 1996 to march 1999.
• 4 male, 2 female. Youngest being 6 years and the oldest being 17 years.
• Ethilogy for 4 pts being trauma during 1st
decade and other two suffered from otitis
• All pts were not treated previously and had complete bony ankylosis.
• Obstructive sleep apnea was the principal complaint in 5 pts. In which 3 of them were
unable to sleep except in the sitting position and had frequent hypoapnoeic episodes
• The pts were treated with sagittal split ramus osteotomy and immediate coronoid
process grafts. A fibular graft was used to stabilize mand segment in 4 pts.
• GA via nasotracheal intubation in 2 pts and via tracheostomy in 4 pts.
• Mandible approached through combined retromandibular and extended pre auricular
• The retromandibular incision was made 5 cm below the lobe of the ear and 2.5cm
behind the angle of the mandible on the anterior border of the sternocleidomastoid
• The scm muscle was retracted posteriorly, the parotid gland upward, and the skin
fascia flap forward.
• Through this incision the angle of the mandible and post border of the ramus were
exposed. Then the pterygomassetric sling was striped completely from its
• An extended pre auricular incision was made next. After retracting the
flap, the superficial temporalis fascia was incised at 45o
at the root of the zygomatic arch and extending upward to a point 2cm
above the arch deep to temporal fat pad.
• The reflected flap included the superficial temporalis fascia, periosteum,
temporal fat pad, and the zygomatic and temporal branches of the facial
• Then the ankylosed condyle was resected and removed takin care not to
injure the internal max artery behind and deep to the osseous mass.
• A space atleast 1.5 to 2cm between zygomatic arch and superior margin of
the ramus was created.
• Then the coronoid process was detached with a reciprocatig saw and was
used to replace the resected ankylosed condyle.
• The glenoid fossae was created by trimming with rose-head burs, a small
flap of temporalis fascia or muscle was inserted in the gap to prevent
• Now the horizontal cortical osteotomy of the sagittal split was made. This
cut was continued down the external oblique ridge to the second molar
• The lateral vertical cortical osteotomy was started just distal to the
second molar and was extended to the inferior border of the mandible.
• Then to initiate the actual plane for the split, a thin, straight osteotome
and a bone splitter were alternately malleted into the area parallel to and
just beneath the lateral cortex.www.indiandentalacademy.com
• After condylectomy and bsso, the mandible was pulled forward and
rotated into a reasonable position for restoring the occlusion.
• The coronoid process graft was rotated 180o
and the former anterior
border of the segment was alligned with the post border of the ramus.
• The tip of the coronoid process graft was also alligned in the newly
fashioned glenoid fossa and fixed to the ramus with a microplate and
• If both the buccal and lingual cortices were not strong enough or if their
overlap was inadequete, a fibular bone graft was used to stabilize the
• A maxillo-mandibular fixator was used for six weeks.
• All patients mouth opening and aesthetic appearances were found to be
• Both mentolabial and mentocervical angles had returned to normal shape
in late examinations.
• The alignment between middle 3rd
and lower 3rd
of the face had become
normal after 1 or 2 years.
• In 5 cases, the OSAS disappeared completely immediately after surgery.
• One pt only had a interincisal opening of 10mm after 1 year that was
related to his poor compliance with mouth opening exercises.
• Bilateral tmj ankylois developing during the active growth period is often
complicated by development of secondary changes such as the body and
ascending rami fail to develop, the chin recedes, and the coronoid process
is markedly elongated and thickened.
• The temporalis muscle is stronger and hypertrophic, and the suprahyoid
muscle group is shorter and hypertrophic.
• Respiration can be severly jeopardized, causing snoring and OSAS.
• The method chosen for the reconstruction of the ramus and condyle in a
pt with tmj ankylosis not only should provide a functional joint but also
help restore the facial profile.
• Autogenous costochondral rib grafts have been used as a substitute for
mandibular ramus and condyle,
• Several studies have shown that in children costochondral grafts have the
potential to grow. However, this factor alone doesnot mean that growth
will always proceed normally .
• Growth of these grafts is unpredictable, ranging from resorption to
overgrowth and sometimes necessating secondary surgical procedure.
• The coronoid process of patients with long standing tmj ankylosis is
longer and thicker so it could be used to take the place of the condyle and
lengthen the mandibular ramus, thus avoiding a second surgical site.
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