Orthognathic Surgery
Introduction
Clefts
of the Lip and Palate
Ear
Reconstruction
Craniosynostosis
Orbital Reconstruction
Treacher Collins Syndrome
Nasal Reconstruction
Orthognathic Surgery Trauma
Reconstruction
Hemifacial
Microsomia
Summary
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Orthognathic surgery refers to the surgical
repositioning of the maxilla, mandible, and the dentoalveolar segments
to achieve facial and occlusal balance. One or more segments of the
jaw(s) can be simultaneously repositioned to treat various types of
malocclusions and jaw deformities.
Preoperative diagnosis and planning for
patients with jaw asymmetries and deformities includes a photographic
analysis and a complete orthognathic work-up involving cephalometric and
panorex radiographs, dental impressions, and models. This is done by the
Pedodontist/Orthodontist in coordination with the craniofacial surgeon.
All findings are analyzed and pre-surgical model surgery performed to
ascertain the feasibility of various treatment options. Additionally,
computer analysis is done pre-surgically by the craniofacial surgeon to
simulate surgical results, thereby facilitating proper planning of the
case. Computer analysis provides the craniofacial team with visual
information and numerical data that is a compilation of many
time-consuming calculations such as those used in various cephalometric
analyses (Steiner, Ricketts, or Jarabak-Bjork).
Usually, pre-surgical orthodontics are
necessary to straighten the teeth and align the arches so that a stable
occlusion can be obtained post-operatively, while orthodontics following
surgery are frequently required to revise minor occlusal discrepancies.
Orthognathic surgery is often delayed until after all of the permanent
teeth have erupted unless medical conditions necessitate that the
surgery be performed earlier. In adult patients, orthognathic surgery
can be combined with soft tissue contouring to improve the aesthetic
results.
Maxillary advancement is a type of
orthognathic surgery that may be necessary to improve the facial contour
and normalize dental occlusion when there is a relative deficiency of
the midface region. This is done by surgically moving the maxilla with
sophisticated bone mobilization techniques and fixing it securely into
place. For most patients, the use of screws and miniplates have replaced
wiring of the bone and teeth required to hold the jaw stable. Inlay bone
grafts can be utilized for space maintenance and secured with screw and
plate fixation, while onlay bone grafting is used to augment the bony
skeleton and improve facial soft tissue contour.
Depending on the soft tissue profile of
the face or the severity of an occlusal discrepancy, problems with the
lower face may require surgery on the mandible. This can be done in
conjunction with or separate from maxillary surgery. The mandible can be
advanced, set back, tilted or augmented with bone grafts. A combination
of these procedures may be necessary. Pre-operative planning is crucial
to the success of the procedure and evaluates the surgical and
orthodontic options. The surgeon chooses the type of mandibular surgery
based on his experience, evaluation of the photographic and
cephalometric analysis, and model surgery. Following any significant
surgical movement of the mandible, fixation may be accomplished with
miniplates and screws or with a combination of interosseous wires and
intermaxillary fixation (IMF). Rigid fixation (screws and plates) has
the advantage of needing limited or no IMF. However, if interosseous
wiring is used, IMF is maintained for approximately six weeks.
Nutritionally balanced, blenderized diets are important for proper
healing in the patient in IMF.
The chin is an important component of the
facial profile as well as the aesthetic balance. The position and
projection of the chin should be evaluated in patients considering
orthognathic and facial soft tissue contouring procedures. Photographic
and cephalometric analysis help determine the amount of change necessary
to obtain a well balanced face. The chin can be augmented with such
alloplastic materials as silicone, polyethylene or hydroxyapatite.
However, most craniofacial surgeons prefer a sliding horizontal
osteotomy genioplasty. This procedure tends to give a more natural
contour to the chin and avoids the risk of extrusion that goes along
with alloplastic implants.
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Orthognathic
Surgery |
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| Nineeen
year old female with maxillary hypoplasia, malocclusion and
facial disharmony. |
Postoperative
result
after combined maxillary/mandibular procedures to correct
occlusion and improve facial balance. |
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| Twenty
year old male with prognathic mandible. |
Postoperative
result after mandibular set back. |
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| A
young woman with a prognathic mandible and hypoplastic maxilla. |
postoperative
result after maxillary advancement and mandibular set back. |
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| Twenty
year old woman with microgenia |
Postoperative
result after orthognathic surgery and chin advancement showing
improvement in lower facial profile. |
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Seventeen
year old patient with micrognathia (hyperplastic lower jaw). |
Postoperative
result after mandibular advancement. |
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Seventeen
year old girl with ectodermal dysplasia. She has a hypoplastic
maxilla and an enlarged mandible.
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Seventeen
year old patient with micrognathia (hyperplastic lower jaw). |
Postoperative
result after mandibular advancement. |
The Tennessee Craniofacial
Center, part of the Erlanger Health System, is located in Chattanooga,
Tennessee. The Center, led Larry A. Sargent, M.D., specializes in the
evaluation and treatment of patients of all ages with craniofacial deformities.
Location:
975 East Third Street. Chattanooga, Tennessee 37403
Phone: 423-778-9192 or 800-418-3223 Fax: 423-778-8172
Internet: www.craniofacialcenter.com Copyright ©1997, 2000, Erlanger
Health Systems
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