Authors of section

Authors

Scott Bartlett, Michael Ehrenfeld, Gerson Mast, Adrian Sugar

Executive Editor

Edward Ellis III

General Editor

Daniel Buchbinder

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Four wall box osteotomy

1. Planning of surgery

The interorbital distance and the vertical discrepancy between the orbits are measured with a caliper. For vertical repositioning, a wedge of supraorbital bone must be removed. When If there is also a horizontal discrepancy, bone needs to be removed medially to allow the orbit to be repositioned.

Note: This surgery should not be performed until after the maxillary teeth have erupted sufficiently that they will not be damaged by the osteotomy cuts.

Hemifacial microsomia (HFM) - Four wall box osteotomy

2. Approach

A coronal approach is used where only the anterior portion of the temporalis muscle is elevated.

Additional exposure through transconjunctival or trans oral approaches are performed so that the orbit can be degloved 360 degrees leaving the medial canthal tendon attached (some surgeons detach the medial canthal tendon and reattach it at the end of the procedure).

3. Four wall box osteotomy

Superior wall osteotomy (craniotomy)

After the exposure of the forehead and the orbits, a unilateral frontal craniotomy beginning 1 cm above the superior orbital rim and extending from the midline to behind the coronal suture is outlined.

Burr holes are first placed at the vertex 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.

Hemifacial microsomia (HFM) - Four wall box osteotomy

After the bone flap is removed, the brain is freed from the anterior and middle fossa in the epidural plane.

The surface of the brain is protected by neurosurgical cottonoids.

Hemifacial microsomia (HFM) - Four wall box osteotomy

Lateral and orbital osteotomies

Malleable retractors are used intracranially to protect the brain and intraorbitally to protect the orbital contents.

Hemifacial microsomia (HFM) - Four wall box osteotomy

With retractors in the orbit and anterior cranial fossa, an osteotomy beginning just posterior to the lateral orbital rim and through the lateral orbital wall is made.

Hemifacial microsomia (HFM) - Four wall box osteotomy

A vertical osteotomy is performed at the junction of the zygomatic arch and zygomatic eminence.

Hemifacial microsomia (HFM) - Four wall box osteotomy

An osteotome is introduced from the temporal fossa and a cut is made along the deep orbital floor to the level of the posterior portion of the inferior orbital fissure.

The lateral orbital floor is cut with an osteotome placed just behind the lateral wall at the level of the zygoma and courses medially to join the osteotomy of the medial orbit.

Note: The inner orbital osteotomies of the floor, medial and lateral walls and roof should be behind the equator of the orbit to ensure that when the orbit is moved it takes the globe of the eye with it.

Hemifacial microsomia (HFM) - Four wall box osteotomy

A right angle saw is then turned intracranially and the orbital roof is cut beginning at pterion laterally and ending at the cribriform plate.

Hemifacial microsomia (HFM) - Four wall box osteotomy

An osteotome is then inserted at the pterion and the lateral orbital wall cut completed if needed.

Hemifacial microsomia (HFM) - Four wall box osteotomy

An osteotome is then inserted from intracranially and the medial orbit is cut posterior to the canthus and on to the medial floor.

Hemifacial microsomia (HFM) - Four wall box osteotomy

Inferior wall osteotomy

Using the upper buccal sulcus or lid incision, a saw is used to cut from the zygomatic eminence below the infraorbital nerve to the pyriform buttress.

Hemifacial microsomia (HFM) - Four wall box osteotomy

Medial wall osteotomy

A single cut is then made from the anterior cranium down the affected side of the nasal bone to the bone cartilage junction.

Hemifacial microsomia (HFM) - Four wall box osteotomy

4. Mobilization and fixation

Mobilization and fixation of orbits

The orbit should now be completely mobile and able to be translocated superiorly. Any interference with bone spicules or ethmoid sinus tissue may need to be removed with a rongeur. There may be interference at the pyriform level as well requiring bony removal.

Hemifacial microsomia (HFM) - Four wall box osteotomy

The orbit may also need is be rotated a little and possibly advanced laterally. Temporary fixation can be secured with a one or two wires superiorly. The definitive new position of the orbit is then fixed with 1.5 mm titanium plates and screws.

Hemifacial microsomia (HFM) - Four wall box osteotomy

The frontal craniotomy has to be reduced before it is replaced and fixed with miniplates and screws. This provides bone grafting material which is then used to fill in gaps, especially below the inferior osteotomy on the anterior wall of the maxilla.

Hemifacial microsomia (HFM) - Four wall box osteotomy

Note: 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 need be performed. 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. Lateral canthal resuspension may also be performed. Further details can be found in the section on nasal ethmoid fractures.

Some surgeons will also place transnasal sutures tied over gauze to help the soft tissue adhere to the new nasal bone position.

Some surgeons continue to 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.

Hemifacial microsomia (HFM) - Four wall box osteotomy

5. Aftercare following transcranial and Le Fort III procedures in infants and children

Intraoperatively

Most surgeons favors placement of a bulb suction drain for 3-5 days. Resorbable skin sutures are often used.

Postoperatievely

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.

Postoperative positioning

Keeping the patient’s head in an upright position postoperatively may significantly improve periorbital edema and pain. Some surgeons use injectable cortico steroids during surgery to reduce periorbital swelling.

Nose-blowing

To prevent orbital emphysema, nose-blowing should be avoided for at least 10 days.

Medication

The use of the following perioperative medication is controversial. There is little evidence to make strong recommendations for postoperative care.

  • No 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 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.

Ophthalmological examination

Postoperative examination by an ophthalmologist may be requested, although sever periorbital edema may prevent useful assessment. The following signs and symptoms are usually evaluated:

  • Vision
  • Extraocular motion
  • Diplopia
  • Globe position
  • Lid position

Postoperative imaging

Postoperative imaging has to be performed within the first days after surgery. 3-D imaging (CT, cone beam) is recommended.

Wound care

Remove sutures from skin after approximately 7-10 days if nonresorbable sutures have been used.
Apply ice packs 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.

Diet

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.

Follow-up

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.