Bilateral Subcranial Le Fort III Osteotomies with Midface Distraction – A Surgical Review

Procedure In this video, we showcase the bilateral subcranial Le Fort III osteotomies with midface distraction using Kawamoto distractors.   Introduction The surgery was performed in a 4-year-old boy with Crouzon Syndrome to correct his severe proptosis, increase the nasopharyngeal airway space and improve his severe negative overjet.  Internal distractors were chosen to achieve maximum correction at this age.   Indications/Contraindications The Lefort III osteotomies are an effective treatment of proptosis, midface hypoplasia, and obstructive sleep apnea, often seen in Apert, Crouzon, and other craniofacial synostotic syndromes. The operation is generally not performed in children under three years of age or if a significant psychosocial and or physiologic benefit can be achieved.   Materials and Methods Osteotomies are performed at the zygomatic arch, infraorbital fissure, zygomaticofrontal junction, nasofrontal junction, and the pterygomaxillary junction (Figure 1). The osteotomies are performed with an electric bone saw or a sonopet, and full separation of the midface from the cranial base is achieved with osteotomes, smith spreaders, and Rowe disimpaction forceps. As a final step, the internal distractors are attached to achieve mid-face distraction.   Results The patient undergoing surgery had no intraoperative or postoperative complications. A full separation of his facial bones was achieved. The patient had an uneventful recovery period, and there was a significant improvement in his proptosis and malocclusion.   Conclusion If a careful selection of surgical candidates is made, the Lefort III osteotomies can lead to a significant improvement in the structural and functional symptoms experienced by patients with craniosynostosis, proptosis, and midface hypoplasia.

The cranial Le Fort III osteotomies allow for the movement of the entire orbitozygomatic body and maxilla in one unit away from the cranial base.1 Through distraction osteogenesis, expansion of the orbits and improvement of midfacial position and occlusion are achieved in addition to gradual stretching and relaxation of the soft tissues.2 In many cases, the increased oropharyngeal and nasopharyngeal volume created can lessen sleep apnea and allow for eventual decannulation of a tracheostomy. 2 The Lefort III osteotomies are indicated for patients suffering from syndromic craniosynostosis, proptosis, and midface hypoplasia as seen in Apert, Crouzon, and other craniofacial synostotic syndromes.3   The patient presented in this video is a 4-year-old boy with Crouzon Syndrome, severe proptosis, malocclusion, and obstructive sleep apnea. We determined that he was a surgical candidate, as his comorbidities did not increase his post-operative complications more than expected. After evaluation, we determined that the anterior advancement of his orbitozygomatic body and maxilla would increase the space available for his eyes, and would improve his airway, which would simultaneously improve his severe proptosis and obstructive sleep apnea. Some of the complications we informed the parents about included hemorrhage, CSF leak, neurological impairment, infection, injury to orbital structures leading to full or partial blindness, and movement of facial bones to an undesired position leading to structural and functional problems. Our surgical team and the patient’s family came to a consensus that the benefits of the procedure outweighed the potential complications. We chose to use bilateral KLS (Mulheim, Germany) internal Kawamoto distractors for this operation. The use of distractors is indicated in the growing child and would allow a greater degree of skeletal correction when compared to conventional osteotomy with rigid fixation.4 Additionally, the internal distractors would be less visible, and thus more socially acceptable than the rigid-external distractors.5 The disadvantage of using internal distractors is that a second procedure is needed to remove the devices and that once they are set in place, their distraction vector cannot be modified.5 On the other hand, the external distraction devices can be modified any time after the procedure.6

The special instrumentation used in this procedure was the Kawamoto internal distractors made by the (KLS Martin Group, Muhlheim, Germany).7 The osteotomies are performed with an electric bone saw or a sonopet, and full separation of the facial bones is achieved with osteotomes, Smith spreaders, and Rowe disimpaction forceps. The patient was brought to the operating room and set up began as he was placed on the table in the supine position. After satisfactory induction of general anesthesia, tarsorrhaphy sutures were performed with a 5-0 nylon suture through the upper and lower eyelid to protect the patient’s eyes due to his severe proptosis. A throat pack was inserted to prevent contamination of his upper aerodigestive tract. The entire head and face were sterilized with betadine paint.   The patient’s old coronal incision from his original craniosynostosis repair was injected with 1% lidocaine with epinephrine. A 3D Computed Tomography was performed as a part of the pre-operative workup.   To begin the operation, an incision was made overlying the patient’s old coronal incision sites. The scalp was dissected downward to the subperiosteal plane until the level of the temporalis muscle, which was elevated up to the level of the lateral orbital rim and nasofrontal junction. The temporalis flap was raised from the scalp bilaterally to reach the zygomatic root or the body of the zygoma. A 360-degree dissection around both orbits was done in order to get a clear view of the infraorbital fissure and the anterior ethmoid arteries. The anterior arms of the Kawamoto plates were attached bilaterally with a total of 8 screws. The posterior arms of the distractors were aligned with the occlusal plane and were left unattached to allow for precise alignment with the contralateral side. The osteotomies began at the zygomatic arch. Followed by a cut going from the infraorbital fissure up to the horizontal cut of the zygomaticofrontal junction. The infraorbital fissure was identified, which is where the osteotomy begins and joins up with the horizontal cut at the zygomaticofrontal suture.8 The next cut was done at the nasofrontal junction and nasal septum, which was followed by medial cuts to complete the nasofrontal disjunction. The osteotomy was done below the anterior ethmoidal artery in order to prevent injury to the cribriform plate leading to a CSF leak.8 Special attention was also taken to ensure that the medial cuts at the nasofrontal junction were done posterior to the lacrimal groove to prevent injury to the medial canthal tendon attachments.8 The osteotomies were finalized with vertical cuts to the pterygomaxillary junction. A full separation of the facial bones was achieved with osteotomes, Smith spreaders, and Rowe disimpaction forceps. The Rowe disimpaction forceps and a palatal splint were used to gingerly but firmly  disimpact and mobilize the maxilla and subcranial face in one unit. A tongue depressor was placed in the mouth to approximate the location of the occlusal plane. The posterior distraction arms were set parallel to the occlusal plane and were fixed in place with a combination of 5 cm and 7 cm screws. The double joint arms were attached to the distraction devices bilaterally. The scalp was set back in place, and the incisions were sutured with 5-0 Nylon.

The patient had no intraoperative or immediate postoperative complications. The operation achieved a full separation of his facial bones by the operation. The advancement was done for 43 days, and a total of 29 mm of distraction were achieved. In order to promote bone consolidation, the distractors were left in place for a period of 2 months. The patient’s mother was satisfied with the advancement results. Since the distractors allow for a maximum of 30 mm of advancement, no further advancement was possible with the internal Kawamoto distractor devices. As distraction advanced, however, approximately half-way into activation, there was a small fracture in the left medial orbital rim, and thus the central nasal unit did not advance as much as it was expected. At the end of the 2-month consolidation period, the distractor devices are scheduled to be removed. At that time, because of the incomplete correction of the central midface, consideration may be given to repeat distraction with an external device.

The specific osteotomies performed in the Le Fort III allow for the movement of the orbitozygomatic body and maxilla in one unit away from the cranial base. Through distraction osteogenesis, expansion of the orbits and improvement of midfacial position and occlusion are achieved. It is important, however, to acknowledge that the results of the distraction may vary depending on the patient’s age and bone maturation. The use of distractors allows for greater bone mobility when compared to conventional osteotomy with rigid fixation. Furthermore, distractors provide various options for repositioning including advancement of the face, vertical rotation of the face, and minor transverse rotation of the face.4,10 Our choice of internal rather than external distractors had the advantage that they were less visible, and are thus more socially acceptable than the external distractors.5 The disadvantage of using internal distractors is that a second procedure is needed to remove the devices.5 A second downside to the internal devices is that once they are set in place, their distraction vector cannot be modified, which is different from the external devices which can be modified at any time.5 In this patients' case, the fracture of the left orbital rim might have indicated that we needed to make our intra-orbital osteotomy further back from the orbital rim. At the time of device removal, depending on how the bone appears on CT scan, repeat Le Fort III distraction may be considered. A new sleep study will also be obtained to quantify the degree of correction of sleep apnea. If significant gains have been made and depending on parent preference, a definitive LeFort II operation will be scheduled once he is skeletally mature.9   The eventual goal would be decannulation and correction of the severe class III malocclusion.   If a careful selection of surgical candidates is made, the Lefort III osteotomies can lead to a significant improvement in the structural and functional symptoms experienced by patients with craniosynostosis, proptosis, and midface hypoplasia, in addition to significant psychosocial improvement.

The authors have no conflicts of interest to disclose.

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1. Shetye P, Giannoutsos E, Grayson B, McCarthy J. Le Fort III Distraction: Part I. Controlling Position and Vectors of the Midface Segment. Plast Reconstr Surg. 2009;124(3):871-878. doi:10.1097/prs.0b013e3181b17b57 2. Diner P. Le Fort III Advancement with Gradual Distraction Using Internal Devices. Plastic & Reconstructive Surgery. 1997;100(Supplement 1):831,832. doi:10.1097/00006534-199709001-00002 3. Mathijssen I. Guideline for Care of Patients With the Diagnoses of Craniosynostosis. Journal of Craniofacial Surgery. 2015;26(6):1735-1807. doi:10.1097/scs.0000000000002016 4. Rapp S, Uribe-Rivera A, Pan B, Billmire D, Gordon C. Outcomes and Analysis When Utilizing a Minimal Incision Lefort III Osteotomy and Rigid External Distraction on Syndromic Patients with Obstructive Sleep Apnea. Plast Reconstr Surg. 2013;132:123. doi:10.1097/01.prs.0000436003.41308.3e 5. Lao W, Denny A. Internal Distraction Osteogenesis to Correct Symptomatic Cephalocranial Disproportion. Plast Reconstr Surg. 2010;126(5):1677-1688. doi:10.1097/prs.0b013e3181ef8f65 6. Polley J, Figueroa A. Management of Severe Maxillary Deficiency in Childhood and Adolescence Through Distraction Osteogenesis With an External, Adjustable, Rigid Distraction Device. Journal of Craniofacial Surgery. 1997;8(3):181-185. doi:10.1097/00001665-199705000-00008 7. Klsmartin: Kawamoto Midface Distractor. Klsmartinnorthamerica.com. http://www.klsmartinnorthamerica.com/products/distraction-devices/lefort-iii-and-monobloc/kawamoto-midface-distractor/. Published 2018. Accessed November 28, 2018. 8. Orra S, Tierney W, Capone A, Gharb B, Papay F, Doumit G. Relevant Surgical Anatomy of Pterygomaxillary Dysjunction in Le Fort III Osteotomy. Plast Reconstr Surg. 2017;139(3):701-709. doi:10.1097/prs.0000000000003084 9. Caterson E, Shetye P, Grayson B, McCarthy J. Surgical Management of Patients with a History of Early Le Fort III Advancement after They Have Attained Skeletal Maturity. Plast Reconstr Surg. 2013;132(4):592e-601e. doi:10.1097/prs.0b013e31829f4b11 10. Hettinger P, Hanson P, Denny A. Le Fort III Distraction Using Rotation Advancement of the Midface in Patients with Cleft Lip and Palate. Plast Reconstr Surg. 2013;132(6):1532-1541. doi:10.1097/prs.0b013e3182a97ebc