For the midface deformity, a Le Fort III or monoblock osteotomy is required.
A monoblock osteotomy done transcranially is utilized when the forehead, orbits, and midface all require a similar magnitude of advancement.
The "standard" Le Fort III osteotomy is performed when the superior orbital rim and forehead are in a satisfactory position and only the midface requires advancement.
The Le Fort III osteotomy using conventional fixation and bone grafts is usually performed after craniofacial growth is complete, although some proponents do it during the period of growth.
More often the Le Fort III osteotomy is done via distraction osteogenesis in the younger patients in order to overcorrect the deformity, reduce complications, obviate the need for bone grafts, and hopefully reduces the total number of operations the child might need.
The conventional monoblock osteotomy can also be done as a single stage or…
…via distraction in children up to age 6-8 years. Single stage advancements are not often done after this age due to the excessive risk of complications (infections, CSF leak, etc.).
2. Preparation and approach
Preparation of occlusal splint
The patient is prepared for surgery with presurgical orthodontia and fabrication of an occlusal splint to establish a Class I relationship or, if overcorrection is desired, the desired occlusal relationship.
The patient is placed in a supine position on a well-padded headrest.
Nasal intubation is required as the patient will be placed in temporary MMF during the procedure.
The osteotomy is approached through a coronal incision with or without an upper buccal sulcus 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. Similarly the osteotomies can usually be done without a buccal sulcus incision.
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 fossae 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 when performing the osteotomies.
Vertical osteotomies are made just behind the lateral orbital rims and down through the lateral orbital wall with a saw.
A vertical osteotomy using a saw at the junction of the zygomatic arch and zygomatic body is completed.
With the brain carefully retracted, 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 inserted from intracranially and the medial orbit is osteotomized behind to the canthus and on to the medial floor.
An osteotome is used to perform osteotomies across the orbital floor anterior to the inferior orbital fissure, connecting to the medial wall osteotomies.
Separation of pterygomaxillary junction
The osteotomy through the pterygomaxillary junction is completed with a curved osteotome from the infratemporal fossa or transorally if an upper buccal sulcus incision has been made.
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.
Cut of the nasal septum
The final osteotomy is made from intracranially and goes from the cribriform plate through the posterior septum to the level of the palate.
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.
Disimpaction forceps are then introduced and the midface is down- and out-fractured, mobilizing it completely.
5. Positioning and fixation
Positioning of midface with MMF
The patient is then placed in MMF using the occlusal splint and stainless steel wire loops.
Fixation of the midface
Once the desired vertical dimension is established, fixation with titanium plates and screws (1.5 or 2.0 mm) at the zygoma and temporal region secures the advancement.
If the monoblock procedure is being performed in a child above the age of 6-8 years as a single stage, there is a high risk of CSF leak and/or infection. Therefore the anterior cranial base in the midline is usually filled with a galea frontalis flap and tissue sealant (eg, Fibrinogen etc.).
This may require cutting a small notch out of the frontal bone to prevent constriction of the flap.
Grafting of bony gaps
The bony gaps are then filled with bone grafts wedged into position and secured to the plate. Inlay bone grafts may also be placed along the orbital floor.
Fixation of frontal bone flap
The frontal bone flap is then replaced and affixed to the supraorbital rim with titanium plates and screws.
Grafting of coronal bone gap
The coronal bone gap created from the advancement is then filled with particulate bone shavings harvested with a manual hand-held burr-hole instrument or commercial harvester (eg. Safe scraper) from the frontal bone flap or the posterior skull.
Positioning of midface with MMF
Most patients with Syndromic synostosis have canthal malposition so a lateral canthopexy in an overcorrected superior position is completed prior to closure.
7. Removal of MMF
If the advancement is thought to be secure, the MMF may be removed, but most surgeons prefer a period of 3-6 weeks of MMF.
8. 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.