Management of Severe Maxillary Hypoplasia with Distraction Osteogenesis in Patients with Cleft Lip and Palate Hitesh Kapadia
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Management of severe maxillary hypoplasia with distraction osteogenesis in patients with cleft lip and palate Hitesh Kapadia Maxillary hypoplasia is a common finding in patients with cleft lip and palate. Clinically, this manifests as a concave profile, midface deficiency, and Class III skeletal malocclusion. Management is in accordance with the severity of the malocclusion. In the case of moderate to severe skeletal discrepancy, combined orthodontic and surgical correction is required to obtain optimal results. In most instances, definitive orthognathic surgery is pursued at skeletal maturity. In the most severe cases however, early surgical correction has been achieved with Le Fort I osteotomy and distraction osteogenesis. The technique enables successful correction of a large maxillomandibular discrepancy in a growing patient with stable results. There are also applications in a skeletally mature patient with severe maxillary deficiency. (Semin Orthod 2017; 23:314–317.) & 2017 Elsevier Inc. All rights reserved. istraction osteogenesis (DO) has its origins bones. This serves to restore the periosteum and D in orthopedic surgery. The technique was allows formation of a bony callus. Using the popularized by Ilizarov in the 1940s to lengthen distraction appliance, the bone segments are long bones without the need for a graft.1 gradually pulled apart during the activation McCarthy et al.2 in 1992, was the first to report phase. This allows for formation of immature a craniofacial application in patients with bone or regenerate across the osteotomy. The congenital deformities of the mandible. It was rate of distraction is typically 1 mm per day.4 subsequently adapted to the midface and upper Once the planned position of the bone is craniofacial skeleton.3 reached, the newly formed regenerate is The goal of DO is to create new bone across an allowed to mineralize during the consolidation osteotomy site by gradually moving the two sides phase. In addition to bone remodeling, this time of the bone apart. As with traditional orthog- is important as it allows for expansion of the soft nathic surgery, distraction begins with the tissue envelope to adapt to the changes in the osteotomy. This is coupled with placement of the underlying skeleton. The distraction appliance distraction appliance. The appliance may be is maintained in place until removal after internal or external and depends on clinical 6–8 weeks in consolidation. presentation of the deformity and surgeon The traditional management of severe maxillary preference. There are three distinct phases in hypoplasia in cleft lip and palate (CLP) poses a distraction: latency, activation, and con- challenge for the cleft team. The patient must be solidation. During the latency or lag phase, initial skeletally mature prior to definitive orthognathic bone formation occurs at the gap between the surgery. During the adolescent years, there are few corrective options for a patient experiencing psy- chosocial difficulties related to midface hypoplasia. Seattle Children’s Hospital, Craniofacial Center, Seattle, WA. From the standpoint of establishing a harmonious Address correspondence to Hitesh Kapadia, DDS, PhD, Seattle maxillo-mandibular relationship, this may only be ’ Children s Hospital, Craniofacial Center, 4800 Sand Point addressed with traditional orthognathic surgery Way NE, OB.9.520, Seattle, WA 98102. E-mail: hitesh.kapadia@ when craniofacial growth has ceased. With more seattlechildrens.org – & 2017 Elsevier Inc. All rights reserved. severe anterior posterior discrepancies, correction 1073-8746/12/1801-$30.00/0 of the malocclusion may involve both maxillary http://dx.doi.org/10.1053/j.sodo.2017.05.007 advancement and mandibular setback, as a large Seminars in Orthodontics, Vol 23, No 3, 2017: pp 314–317 314 Downloaded for Anonymous User (n/a) at Seattle Children's from ClinicalKey.com by Elsevier on January 23, 2019. For personal use only. No other uses without permission. Copyright ©2019. Elsevier Inc. All rights reserved. Management of severe maxillary hyopolasia with distraction osteogenesis 315 Figure 1. LFI maxillary distraction osteogenesis in a 14-year-old male with severe maxillary hypoplasia, bilateral cleft lip and palate, Van der Woude syndrome, and hypodontia. (A) Pre-treatment facial photographs, lateral cephalogram and intraoral photographs showing severe maxillary hypoplasia and resulting maxilla–mandibular discrepancy. (B) Pre-LFI DO: the dental arches have been coordinated in preparation for surgery. (C) LFI DO: external distraction appliance with bone anchored maxillary traction plates are used to advance maxilla to over- corrected position to account for anticipated mandibular growth. (D) Post-LFI DO: photographs and radiographs showing resolution of maxillary hypoplasia and improvement in maxilla–mandibular relationship and occlusion. maxillary advancement alone is fraught with With the advent of DO for the midface, the relapse. This may lead to compromised functional management of pronounced maxillary hypo- and esthetic outcomes if the mandible is of an plasia may be dealt with in a growing patient with appropriate size and position. One potential CLP (Fig. 1). This requires coordinated surgical unintended functional outcome of setting back the planning between the surgeon and orthodontist mandible is the adverse effect it could have in as the maxilla must be advanced to the decreasing the size of the oro- and hypo-pharyngeal appropriate position, while taking into account air space. In the case of a large maxillary continued mandibular growth during the mid- to advancement with traditional means, there is the late-teenage years and some degree of skeletal possibility of developing velopharyngeal insuffi- relapse. The goal of DO in a growing patient ciency (VPI). This would require secondary palate would be to establish the ideal position the surgery to restore speech and would be undertaken maxilla with respect to the patient’s underlying in the late teenage years. skeletal pattern of development. With this, the Downloaded for Anonymous User (n/a) at Seattle Children's from ClinicalKey.com by Elsevier on January 23, 2019. For personal use only. No other uses without permission. Copyright ©2019. Elsevier Inc. All rights reserved. 316 Kapadia Figure 2. LFI maxillary distraction osteogenesis in a 15-year-old male with severe maxillary hypoplasia, bilateral cleft lip and palate. (A) Pre-treatment facial photographs, lateral cephalogram, and introral photographs showing severe maxillary hypoplasia with anterior crossbite greater than 15 mm. (B) Pre-LFI DO: the arches have been coordinated for maxillary advancement. (C) LFI DO: external distraction appliance with custom acrylic splint and outriggers for maxillary advancement. The maxilla was overcorrected, taking into account expected mandibular growth. (D) Post-LFI DO: final orthodontic finish showing improved maxillary position and occlusion following maxillary advancement and orthodontic finishing. patient and family must be made aware that there rate associated with Le Fort I DO is 15% after a is the possibility that latent mandibular growth 10 mm advancement.6 The increased magnitude may result in the need for corrective of maxillary advancement with greater stability orthognathic surgery once skeletal growth is can be attributed to the slow and incremental complete.5 movement of the maxilla coupled with The benefits of distraction osteogenesis in a maintaining maxillary position with the use of growing patient with cleft lip and palate include the distraction appliance during consolidation. generation of new bone at the site of osteotomy, For these reasons, DO is also a good treatment large skeletal movement without the need for a option for a patient with CLP and severe maxillary bone graft and gradual stretching of the sur- hypoplasia who is skeletally mature (Fig. 2). rounding soft tissues. Whereas there is a reported Distraction at the Le Fort I level can be 37% relapse rate with conventional Le Fort I achieved with internal or external distraction maxillary advancement of 6.8 mm, the relapse devices. The internal distraction appliance is Downloaded for Anonymous User (n/a) at Seattle Children's from ClinicalKey.com by Elsevier on January 23, 2019. For personal use only. No other uses without permission. Copyright ©2019. Elsevier Inc. All rights reserved. Management of severe maxillary hyopolasia with distraction osteogenesis 317 generally favored by patients, as it is not readily interval to ensure the appropriate vector for the visible. The primary drawback is the inability to intended movement was selected. During this adjust the appliance to change the vector of time, it is also possible to use interach elastics to distraction during the activation phase of dis- guide the maxilla to the optimal occlusion traction.6 By contrast, the external appliance is determined in the pre-surgical plan.6 Once far more conspicuous. It is, however, superior in complete with advancement, the distractor terms of three-dimensional control of the remains in place for 6–8 weeks or longer distraction vector.6 A systematic review of the during the consolidation phase. Following literature by Saltaji et al. suggests the method of bone healing, the distraction devices are distraction as an important predictor of long- removed and orthodontics is reinitiated. The term stability. The internal distractors were primary objective is to maintain the position of found to have higher long-term stability than the midface and optimize the