The interorbital distance is measured with a caliper for reference. The V-shaped osteotomies are planned so as to remove enough interorbital bone so that when the orbits are translocated medially the interorbital distance is normalized to 25 – 30 mm in the adult, and the tilt of the orbit is corrected. This also must take into account leveling of the occlusion. In the younger child this distance may be less, and is based on age and gender matched norms.
Normal interorbital distance (mm)
2. Preparation and approach
Preparation of occlusal splint
The patient is prepared for surgery with fabrication of an occlusal splint from mock (model) surgery performed on plaster models to establish the proper occlusal relationships. In some centers this step is omitted.
The osteotomy is approached through a coronal incision with an upper buccal incision. Extensive dissection of the orbit (deep orbit, anterior and posterior to medial canthus which remains attached), zygoma, midface, and nose is required.
Some surgeons use a lower lid incision as well, but if this can be avoided fewer complications of lid malposition will result.
The following pages provide general information regarding orbital anatomy and dissection
After the exposure of the forehead and the orbits, a bifrontal craniotomy beginning 1 cm above the superior orbital rim and extending to behind the coronal sutures is outlined.
Burr holes are first placed at the vertex, avoiding the sagittal sinus and nasal frontal region as well as temporally. An epidural dissection between these points is made.
The neurosurgeon then completes the osteotomies using a craniotome.
After the bone flap is removed, the dura is freed from the anterior and middle fossaa in the epidural plane.
The dura is protected with neurosurgical cottonoids.
Malleable retractors are used intracranially to retract and protect the dura and intraorbitally to protect the orbital contents while performing the osteotomies.
With retractors in the orbit and anterior fossa, an osteotomy beginning just behind the lateral orbital rim and through the lateral orbital wall is made with a saw.
A vertical osteotomy using a saw at the junction of the zygomatic arch and zygomatic body is completed.
The lateral orbital floor osteotomy is made with an osteotome placed just behind the lateral wall at the level of the zygoma and courses medially just anterior to the inferior orbital fissure to join the planned osteotomy of the medial orbit.
A right angle saw is turned intracranially and the orbital roof is osteotomized beginning at the lateral wall osteotomy and ending at the cribriform plate.
An osteotome is then inserted from intracranially and the medial orbital wall is osteotomized posterior to the canthus and to join the medial orbital floor osteotomy.
Osteotomy of the pterygomaxillary junction
The osteotomy through the pterygomaxillary junction is completed with a curved osteotome from the infratemporal fossa or transorally through the upper buccal sulcus incision.
To assure that the osteotome does not hit vital structures, one usually guides the direction of the osteotome with one hand while a palpating finger is placed medially at the posterior edge of the palate.
Two cuts are then made with a saw from the anterior cranium down the side of each nasal bone to the osteo cartilaginous junction in a V-shaped fashion. The angle of the V and the amount of bone to be removed are determined by the interorbital distances and the amount of rotation of the two hemi-Le Fort III segments one will need.
An upper buccal sulcus incision gives access to the maxillary osteotomy. The V-osteotomy started on the nose is continued on the maxilla, in the midline, and ends between the two central incisors. The osteotomy will need to continue through the hard palate. The small V-shaped segment of maxillary bone is removed. In some patients there is no bony excess here and a midline osteotomy through the maxilla and hard palate is all that is required.
The final osteotomy is made from intracranially and goes from the cribriform plate through the posterior septum to the level of the palate.
(Preservation of some of the cribriform plate may help preserve some sense of smell. For severe hypertelorism this may not be possible.)
It is safest to place a finger in the mouth at the posterior palate to assure the osteotome does not go too deep or penetrate the mucosa.
Removal of the interorbital bone
The interorbital bone is then removed and stripped of mucosa. It may be used as a source for bone grafts.
Disimpaction forceps may be introduced to mobilize the two hemi-facial segments.
5. Mobilization and fixation
The two hemi-facial segments should now be completely mobile and able to be translocated medially. Any interference with bone spicules, ethmoid sinus tissue, or redundant mucosa may need to be removed with a rongeur or scissors. There may also be bony interferences at the pyriform level requiring removal.
Positioning of the segments and fixation
The orbits are rotated medially and the occlusion is leveled as the interorbital distance is reduced and the midface is lengthened. If a splint has been prepared, it is now placed in between the teeth in the proper occlusal relationship and the patient is put into MMF.
The gaps created temporally and along the zygomatic arch are bone grafted with cranial bone and affixed with titanium 1.5 mm plates and screws.
Plate fixation is also used medially between the two orbital segments.
The maxillary halves are stabilized with heavy wire or a small titanium plate.
If resorbable plates are available they may also be utilized as long as stability is assured.
Medial canthopexy (if necessary)
If the medial canthus has not been detached it will be moved with the bone segment. If it has been detached, a transnasal canthopexy will be necessary. This may be performed with wire and metallic plates as in posttraumatic reconstruction, with a bone anchor, or with stout transnasal sutures and bone grafts.
Reshaping and fixation of frontal bone flap
The frontal bone flap is then reshaped and replaced, held in place with titanium screws and plates. This may involve removing segments of bone to allow a good fit with the reshaped orbits, or splicing in segments of bone to get a best fit.
Most often additional nasal projection is required and an onlay cranial bone graft (cantilever bone graft) to the nose needs to be placed (inset). The amount of projection, shape and size of the bone graft depends upon the patient's deformity.
Some surgeons will remove midline redundant skin at this time, while others will do this as a subsequent surgical procedure because it may involve less risk of wound break down and nasal bone graft exposure than when performed during the correction of hypertelorism.
Any residual defects in the cranium are now filled with bone shavings prior to closure of all wounds.
Some surgeons use percutaneous bolsters to ensure adaptation of the skin to the underlying bone. However, these should be applied with great caution to avoid underlying skin necrosis.
MMF may be removed at this point, but many surgeons prefer a period of 3-6 weeks of MMF.
6. Aftercare following transcranial and Le Fort III procedures in infants and children
Most surgeons favors placement of a bulb suction drain under the scalp for 3-5 days. Resorbable skin sutures are often used.
A circumferential head dressing is utilized for 48 hours. The neurosurgeon may request placement of a lumbar drain if significant dural tears have occurred during surgery. Patients should spend at least 1-2 days in an intensive care unit for neurological monitoring.
Keeping the patient’s head in an upright position postoperatively may significantly improve periorbital edema and pain. Some surgeons use injectable corticosteroids during surgery to reduce periorbital swelling.
To prevent orbital emphysema, nose-blowing should be avoided for at least 10 days.
The following perioperative medications are controversial. There is little evidence to make strong recommendations for postoperative care.
Avoidance of aspirin or nonsteroidal antiinflammatory drugs (NSAIDs) for 7 days.
Analgesia as necessary.
Antibiotics (many surgeons use perioperative antibiotics. There is no clear advantage of any one antibiotic, and the recommended duration of treatment is debatable.).
Nasal decongestant may be helpful for symptomatic improvement in some patients.
Steroids may help with postoperative edema. Some surgeons have noted increased complications with perioperative steroids.
Ophthalmic ointment should follow local and approved hospital protocol. This is not generally required in case of periorbital edema. Some surgeons prefer it. Some ointments have been found to cause significant conjunctival irritation.
Regular perioral and oral wound care has to include disinfectant mouth rinse, lip care if intraoral incision has been used.
Postoperative examination by an ophthalmologist may be requested, although sever periorbital edema may prevent useful assessment. The following signs and symptoms are usually evaluated:
Postoperative imaging has to be performed within the first days after surgery to verify accuracy of surgery. 3-D imaging (CT, cone beam) is recommended.
Remove sutures from skin after approximately 7-10 days if nonresorbable sutures have been used. Apply ice packs for the first 12 postoperative hours as able although infants and young children do not tolerate this well (may be effective in a short term to minimize edema). Avoid sun exposure and tanning to skin incisions for several months.
Soft diet can be taken as tolerated until there has been adequate healing of any maxillary vestibular incision. In children and infants age appropriate diets are then prescribed. Patients in MMF will remain on a liquid diet until such time the MMF is released.
Clinical follow-up depends on the complexity of the surgery, and whether the patient has any postoperative problems. Most patients are discharged at postoperative day 3-5 and seen again in 2-3 weeks.
In patients undergoing monoblock or Le Fort III distraction, distraction typically begins at day five at 1 mm/day and is assessed weekly with plane radiographs and clinical examination until the desired position is reached. After advancement a period of consolidation of 1-3 months is recommended before the retractors are removed.
In patients undergoing conventional advancement with intermaxillary fixation, MMF is kept in place for 4-6 weeks. Routine oral hygiene is prescribed. Patients with arch bars and/or intraoral incisions and/or wounds must be instructed in appropriate oral hygiene procedures. The presence of the arch bars or elastics makes this a more difficult procedure. A soft toothbrush (dipped in warm water to make it softer) should be used to clean the surfaces of the teeth and arch bars. Elastics are removed for oral hygiene procedures. Chlorhexidine oral rinses should be prescribed and used at least 3 times a day to help sanitize the mouth. For larger debris, a 1:1 mixture of hydrogen peroxide/chlorhexidine can be used. The bubbling action of the hydrogen peroxide helps remove debris. A Waterpik® is a very useful tool to help remove debris from the wires. If a Waterpik is used, care should be taken not to direct the jet stream directly over intraoral incisions as this may lead to wound dehiscence.
The patient needs to be examined and reassessed regularly and often. Additionally, ophthalmological, ENT, and neurological/neurosurgical examination may be necessary. If any clinical signs for meningitis or mental disturbances develop, professional help has to be sought. Due to the young age of many patients, routing CT-scans are performed only if clinically indicated to avoid excessive radiation exposure.