The procedure presented is a facial biparition-monobloc distraction for the treatment of hypertelorbitism and midface/frontal retrusion. This patient is an 8 year old male with a history of Crouzon syndrome, characterized by hypertelorbitism, midface hypoplasia, frontal flattening and exophthalmos. He was scheduled for a combined facial biparition and monobloc advancement via distraction osteogenesis.

Facial bipartition allows for correction of the hypertelorbitism in both vertical and horizontal planes. In this case, due to the relative preoperative symmetry, a primarily horizontal correction was needed. In order to accomplish the bipartition procedure, a monobloc osteotomy pattern is designed. Prior to downfracture of the monobloc segment, the interdacyron segment is measured. A "V" shaped excision of bone between the orbits is planned to leave 16-20 mm of bone between the medial canthi. After the downfracture the "V" is removed, the bipartition halves are brought together and rigidly fixed. Internal midface distractor devices are then anchored to the temporal bones posteriorly and zygomatic bodies anteriorly. The distractors are returned to neutral position and the coronal incision is closed. A pedicled pericranial flap is used to separate the nasal from the intracranial cavity. The distractor turning arms are brought out through the coronal incisions. After a latency of 7 days, distraction is begun.

The ultimate end point of distraction is correction of the frontal and midface recession. This may result in malocclusion, which is eventually addressed with orthognathic surgery.

Both procedures were necessary to correct his craniofacial dysmorphism and to obtain a significantly improved surgical outcome.