This document describes surgical techniques for treating TMJ ankylosis in children, including:
1. Excising the ankylotic mass through a preauricular incision and reconstructing the ramus condyle unit with either a costochondral graft or distraction osteogenesis.
2. Lining the glenoid fossa with a vascularized temporalis fascia flap to prevent reankylosis.
3. An intensive post-operative physical therapy regimen to regain jaw mobility.
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Kaban protocol tmj ankylosis treatment new 2009
1. 2009 American Association of Oral and
Maxillofacial Surgeons
J Oral Maxillofac Surg 67:1966-1978,
2009
2.
3. The TMJ is approached through a
preauricular incision with a temporal
extension (hemicoronal incision) to expose
the temporalis fascia and muscle,
zygomatic arch, ankylotic mass, and
sigmoid notch.
The periosteum over the arch is incised
horizontally, and the incision is continued
inferiorly over the bony or fibro-osseous
mass and extended to the identifiable
unaffected portion of the ramus.
4. Aggressive excision of the fibrous and/or bony mass is performed.
If any TMJ anatomy is identifiable, the superior osteotomy is extended
into the joint to separate the ramus from the skull base.
If a sigmoid notch is identifiable, the inferior osteotomy is created from
the notch, extending posteriorly at least 1.5 to 2 cm below the margine
of the ankylotic mass.
A bur is used to reshape the skull base into a glenoid fossa.
5.
6. A hole is made at the base of the
coronoid process, and a wire is placed
for traction .
The osteotomy extends from the depth
of the sigmoid notch to the junction of
the horizontal and vertical rami of the
mandible.
Once the osteotomy is completed,the
coronoid is placed on traction with the
wire,
The remaining temporalis muscle and
tendon attachments are cut, and the
entire coronoid is removed.
Coronoid tip removal – inadequate-
reforms and attaches to temporalis
tendon.
7.
8. If an intact disc is identified during
resection of the ankylotic mass, it is
dissected, mobilized, and repositioned
to line the roof of the new glenoid fossa.
In other cases, the TMJ is lined with a
previously described inferiorly based
temporalis muscle fascia flap rotated
over the arch into the joint.
The temporalis flap is pedicled
inferiorly on the deep temporal artery.
9. The deep temporalis fascia and the superficial muscle layer are
transferred to construct a barrier to support the function of the
reconstructed ramus/ condyle unit and to maintain flap vascularity.
10. The flap is sutured medially, anteriorly, and posteriorly to the soft
tissue with 4-0 monocryl suture.
11. 1. Reconstruction with costochondral graft.
2. Reconstruction using distraction osteogenesis.
12. Reconstruction of the ramus condyle
unit (RCU) is achieved with a CCG
obtained by an infra-mammary
incision.
The cartilage is contoured to be no
more than 1 to 2 mm thick and should
be rounded at the edges.
The rib is trimmed and contoured to
produce a good bony interface.
13. The cartilaginous articulating surface of the graft is then placed
against the temporalis flap through the submandibular incision
and rigidly secured with a 2.0-mm titanium bone.
The wounds are closed in layers.
14. The mandibular stump is reshaped to
make it narrow and rounded at the top.
A corticotomy is created distally, leaving
enough bone to serve as a transport
disc.
The distraction device is secured, the
corticotomy completed, and mobility of
the segment tested by activating the
semiburied unidirectional distraction
device ..
Active distraction starts 2 to 4 days after
the operation at a rate of1 mm/day
with a rhythm of 2 or 4 activations daily.
15. Once the transport disc has contacted the skull base, the
distraction is stopped so as not to create pressure on the flap or
disc lining the joint.
The advantages of reconstruction using transport DO are the
lack of donor site morbidity and the ability to start physical
therapy the day of the operation.
16.
17.
18.
19. It consists of active hinge opening
and lateral excursions combined
with manual finger stretching in
front of a mirror.
The exercises are done 4 times
daily for 3 to 5 minutes by the
clock.
At 6 weeks postoperatively, the
diet is advanced to solid foods, and
the “Thera- Bite Jaw Rehabilitation
System is used 4 to 5 times daily for
3 to 5 minutes .
The physical therapy program also
includes heat, massage, and gum
chewing.
If the patient is not able to
achieve the documented
intraoperative MIO, or if the
MIO shows no sign of
improvement at 6 to 8 weeks,
the jaw should be stretched
with the patient under general
anesthesia.
The use of the TheraBite 3 to 4
times daily, gum chewing, and
finger stretching exercises
should be continued for 1 year,
and patients should be
followed closely for at least 1
year.
20.
21.
22. In a more recent retrospective
analysis of 11 children younger
than 16 years of age treated by
this protocol
8 patients had ankylosis secondary
to trauma,
1 had hemifacial microsomia,
1 an infection,
and 1 congenital ankylosis.
In 2 patients, both joints were
affected.
The ramus condyle unit was
reconstructed with either a CCG
(n 6) or DO (n 5).
The patients were followed for a
period of 4 to 74 months (mean
24.8).
The mean preoperative MIO was
11.5 mm (range 1 to 23).
Postoperatively, the mean MIO
was 38.2 mm (range 15 to 49).
Ten of 11 patients had an MIO
greater than 30 mm after the
operation and 1 had to have
fibrous ankylosis release 6 years
after the first operation.
23.
24. Facial asymmetry progressively worsens because of the hypomobility
and abnormal muscle function.
The short ramus condyle unit restricts mid-face growth.
The longer the duration of hypomobility, the more severe will be the
muscle atrophy and facial asymmetry.
If secondary elongation and hypertrophy of the coronoid process
restricting jaw motion
25. A vascularized temporalis myofascial flap is
desirable for lining the joint because the donor
site is in the surgical field, the muscle and fascia
are of adequate thickness, and its long-term
viability.
It also acts as a barrier to excessive bone
formation, fusing the RCU to the skull base.
26. The benefits of a CCG its growth potential, its biologic
compatibility, and its capacity to remodel into a neocondyle with
time.
Its major drawbacks donor site morbidity and reported
unpredictable growth.
Perrott and Kaban described 2types of overgrowth:
1) linear overgrowth resulting in asymmetric or bilateral prognathism;
2) Tumor like overgrowth and reankylosis.
Both types of overgrowth are caused by an excessive cartilaginous cap
on the graft.
The rib growth center is the costochondral junction. A
cartilaginous cap greater than 1 to 2 mm transfers an excessive
portion of the growth center, resulting in linear overgrowth.
27. DO has the advantage of eliminating donor site
morbidity and allowing immediate mobilization ofthe
jaw.
This allows the patient to begin mobilizing the jaw on
the night of the operation.
A major disadvantage is that a growth center is not
transplanted.
Additional surgeries might be necessary to correct any
residual asymmetry after the end of growth.
Editor's Notes
Removing only the tip of the coronoid or simply doing a coronoidotomy is inadequate, because the coronoid reforms and becomes attached and limited by the temporalis tendon and scar.
The protocol is the same as described in the previous section, except for the reconstruction phase.
Untreated TMJ ankylosis in children results in significant adverse consequences.