A Subcranial Le Fort III Advancement With Distraction Osteogenesis

CLINICAL STUDY
A Subcranial Le Fort III Advancement With Distraction
Osteogenesis as a Clinical Strategy to Approach
Pycnodysostosis With Midface Retrusion and Exorbitism
Cassio Eduardo Raposo-Amaral, MD, PhD,* Anne Tong, MD,Þ Rafael Denadai, MD,*
Anisa Yalom, MD,Þ Cesar Augusto Raposo-Amaral, MD,* Debora Bertola, MD, PhD,þ
Andrew Li, MD,Þ and Reza Jarrahy, MDÞ
Abstract: Pycnodysostosis is a rare autosomal recessive skeletal
disorder involving a constellation of craniofacial manifestations
including midface retrusion. We report the case of a 13-year-old girl
with pycnodysostosis who presented with exorbitism, midface
retrusion, malocclusion, and obstructive sleep apnea. Here, we describe the successful use of subcranial Le Fort III advancement using
distraction osteogenesis with internal Kawamoto distracters. After
a latency of 5 days, distraction for 10 days, and consolidation for
12 weeks, her midface was advanced by 10 mm with slight overcorrection at the occlusion level. At 2 years postoperatively, the
patient had complete remission of her sleep apnea, resolution of
her exorbitism, and amelioration of her class III malocclusion to class
I. To the best of our knowledge, this is the first report of a successful
subcranial Le Fort III midface advancement with distraction osteogenesis for craniofacial reconstruction of a pycnodysostosis. Our
report highlights the surgical options that have been described for
this craniofacial deformity and presents a novel and expedient approach for patients with pycnodysostosis presenting with exorbitism,
midface retrusion, and/or sleep apnea.
Key Words: Pycnodysostosis, distraction osteogenesis, midface
retrusion, exorbitism, subcranial Le Fort III advancement
(J Craniofac Surg 2013;24: 1327Y1330)
P
ycnodysostosis (OMIM 265800) is a rare autosomal recessive
skeletal dysostosis resulting from a mutation in the gene encoding cathepsin K, a lysosomal cysteine proteinase that is integral
for normal osteoclastic bone resorption and remodeling.1,2 The disease is characterized by generalized bony sclerosis, bone fragility,
From the *Institute of Plastic and Craniofacial Surgery, SOBRAPAR Hospital, Campinas, SP, Brazil; †Division of Plastic and Reconstructive
Surgery, David Geffen School of Medicine, UCLA, Los Angeles, CA;
and ‡Genetics Unit, Instituto da Criança, Faculdade de Medicina,
Universidade de São Paulo, São Paulo, SP, Brazil.
Received February 13, 2013.
Accepted for publication April 28, 2013.
Address correspondence and reprint requests to Dr. Cassio Eduardo
Raposo-Amaral, Institute of Plastic and Craniofacial Surgery,
SOBRAPAR Hospital, Ave Adolpho Lutz 100, Caixa Postal 6028,
13084-880 Campinas, SP, Brazil; E-mail: [email protected]
The authors report no conflicts of interest.
Copyright * 2013 by Mutaz B. Habal, MD
ISSN: 1049-2275
DOI: 10.1097/SCS.0b013e31829978a5
The Journal of Craniofacial Surgery
short stature, dysplastic clavicles, and numerous craniofacial deformities, including dolichocephaly, persistent patency of 1 or more
of the cranial fontanelles, midface retrusion or hypoplasia, micrognathia, malocclusion, and delayed dental eruption.1,2 Moreover,
osteomyelitis of the mandible3Y5 and recurrent pathologic fractures
of the long bones6 are characteristic complications of this disease,
owing to the impaired vascularity of the bone.7 Diagnosis of this
disease is usually made by the association of the patient’s history and
clinical findings, which is then substantiated by gene studies identifying the cathepsin K gene mutation.1,2
Although pycnodysostosis has a characteristic phenotype
and distinct genetic mutation, the rarity of the disease makes it a
challenging diagnosis to identify.1,2 As such, there are very few reports of surgical management of these patients. Long-term stability
of the midface is one of the primary concerns among craniofacial
surgeons; and although midface advancement would serve as an
effective solution to this problem, there has been apprehension
surrounding the technique’s potential morbidity when used on bone
that is already dysvascular, fragile, and considered unlikely to consolidate appropriately. Thus, craniofacial surgeons may turn away
from midface advancement as a surgical option, and consequently,
what is considered a less morbid orthognatic surgical approach is
often used instead.7 Unfortunately, orthognatic techniques do not
address the clinical exorbitism and midface retrusion, which are
critical features of this disease; and as an unfortunate consequence,
suboptimal aesthetics and postoperative function often result. Therefore, aside from the speculation of potential morbidity, midface
advancement with distraction osteogenesis8,9 would seem to be the
optimal surgical approach for midface retrusion and exorbitism associated with this particular disease.
CLINICAL REPORT
A 13-year-old girl presented to our clinic with obstructive
sleep apnea, inability to spontaneously close her eyelids, and eye
irritation and pain. She had a clinical history significant for craniosynostosis at the age of 15 months, surgically corrected with strip
craniectomy at the coronal suture region, as well as multiple fractures since her first years of life. On physical examination, she was
noted to have short stature, midface retrusion, class III malocclusion
with dental crowding and posterior crossbite and exorbitism, as
well as acroosteolysis.
Reformatted computed tomographic imaging showed patency
of coronal and lambdoid cranial sutures, retrusion of the midface,
including the zygomatic-orbital regions, and obtuse angle of the
mandible. Plain radiographs showed a small airway pharyngeal
space. Genetic evaluation revealed a p.Arg241X mutation in the
cathepsin K gene, confirming the diagnosis of pycnodysostosis as
previously reported by our group.1
& Volume 24, Number 4, July 2013
Copyright © 2013 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
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The Journal of Craniofacial Surgery
Raposo-Amaral et al
FIGURE 1. Preoperative frontal photography of the patient with
pycnodysostosis (left). Postoperative frontal photography of the same
patient at 2 years after surgery (right).
Given the risk of infection and/or bone nonunion after an
acute subcranial Le Fort III advancement with bone grafting, we
decided to conduct a subcranial Le Fort III advancement with distraction osteogenesis. The procedure was performed through a coronal incision. Bilateral osteotomies were made in the anterior
zygomatic region, lateral orbital wall, medial orbital wall and orbital
floor and ptergomaxillary buttresses, and at frontonasal region. Rowe
disimpaction forceps were used to down-fracture the face and to
promote the final craniofacial disjunction. Bilateral univector internal Kawamoto distracters were fixed to the zygomatic body anterior to the osteotomy site and temporal bone, behind the zygomatic
root and above the external auditory canal. Both devices were tested,
and 2 drains were placed in the coronal region before closure.
The face was brought forward 10 mm, and a slight overcorrection at her occlusion level was performed by the standard
protocol of distraction osteogenesis.8,9 The latency phase was 5 days,
the activation phase was 10 days, and consolidation phase was
12 weeks. At 2 years postoperatively, the patient had complete remission of her sleep apnea, resolution of her exorbitism, and marked
improvement of her class III malocclusion, which converted to a
class II malocclusion immediately postoperatively. Her occlusion
was stabilized at class I with an orthodontic appliance at 2 years after
surgery. She maintains a posterior crossbite that will be corrected
when her growth is complete (Figs. 1Y3).
& Volume 24, Number 4, July 2013
even so, there was very little consensus on which of these approaches
yields optimal long-lasting outcomes in pycnodysostosis.
The major advantage in undertaking orthognathic correction
in patients with pycnodysostosis is the ability to achieve an adequate
correction of the malocclusion without the morbidity of a major
midface advancement. However, orthognatic surgery does not treat
the exorbitism, and even high Le Fort I advancements may also be
inadequate when used to address inferior orbital rim retrusion.
Moreover, orthognatic surgery is not without its own set of complications.12 In particular, transection of bilateral inferior alveolar
nerves has been reported after the creation of bilateral mandibular
osteotomies, contributing factors to this complication being the
sclerotic nature of the bone.16
Della Marca et al18 reported airway augmentation using
adenotonsillectomy and uvulo-palato-pharingoplasty in a 5-year-old
patient with pycnodysostosis and obstructive sleep apnea. Although
effective in treating the sleep apnea and avoiding a highly morbid
tracheostomy, this procedure was unable to address the patient’s
facial dysmorphisms. In contrast, a midface advancement with distraction osteogenesis, commonly used in syndromic craniosynostotic
children with obstructive sleep apnea, can correct both sleep apnea
and midface retrusion without jeopardizing speech function.8,9
Other techniques involving bone grafting have also been
described. Teissier et al14 used autologous rib grafting to advance the
mandible and increase the volume of the pharyngeal port in a young
patient not unlike ours. Although they achieved an excellent result
in the end, there are persistent concerns that the lack of blood supply
of the sclerotic bone in pycnodysostosis still put the patient at undue
risk for osteomyelitis among other associated risks.
Midface advancement either with a subcranial Le Fort III or
a monobloc advancement can simultaneously improve obstructive
sleep apnea secondary to posterior pharyngeal soft tissue crowding
and the exorbitism8,9 without requiring the morbidity of autologous
bone grafting. Our group has extensive experience19 in subcranial
Le Fort III and gradual monobloc advancement in treating craniofacial dysostosis with similar clinical presentation, and for this particular case we decided on the former approach. Interestingly, neither
operative technique has been described as a primary treatment for
pycnodysostosis, although some16,17 have considered distraction
osteogenesis a form of adjuvant care for these patients, regardless
DISCUSSION
The poor bone vascularity and bone sclerosis found in
pycnodysostosis have been cited as risk factors for the development of osteomyelitis of the maxillofacial skeleton and pathologic
facial fractures.3Y5 Moreover, these factors are thought to contribute
to an increased risk for perioperative complications.10Y14 Indeed,
osteomyelitis-induced mandible defects have been repaired with
titanium plates and/or nonvascularized iliac crest grafts.4,5,10,11,13
However, as failure occurred,5,10,13 vascularized iliac bone grafts
and free fibular osteocutaneous flaps have been adopted as more
effective alternatives.13,15
Therefore, the tendency among surgeons has been to use
conservative management techniques for craniofacial abnormalities
associated with pycnodysostosis.16 This notion is reflected in the
literature as our extensive English search (Medline and Embase
databases) revealed a general paucity of reports that describe surgical
methods addressing this disease. Most of what we encountered
regarded the use of orthognatic techniques (Table 1),7,12,14,16,17 and
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FIGURE 2. Preoperative lateral photography of the same patient with
pycnodysostosis (left). Postoperative lateral photography of the same patient
at 2 years after surgery (right).
* 2013 Mutaz B. Habal, MD
Copyright © 2013 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
The Journal of Craniofacial Surgery
& Volume 24, Number 4, July 2013
Le Fort III Advancement
FIGURE 3. Preoperative lateral cephalograms showing the midface retrusion and the superior-inferior dental relation (left). Immediate postoperative lateral
cephalograms taken at day 1 postoperatively, during the latency phase, and at 5 days before the beginning of activation phase (center). This radiographic
imaging showed the positioning of the distracters related to the cranial base and the vectors of the distraction osteogenesis. The distracters were placed parallel
to the other one. Postoperative lateral cephalograms taken at the last day of activation phase showed the amount of movement obtained, in addition to the
dimensions of the posterior airway gained (right).
TABLE 1. Summary of Studies Containing Surgical Approach to Patients with Pycnodysostosis With Craniofacial Abnormalities According to our
Literature Review7,12,14,16,17
Author (y)
Patient
Demographics
(Age, Sex, and
Ethnicity)
Ilankovan and Moos
(1990)
17 y, F, Pakistani
Norholt et al (2004)
15 y, F, Danish
Teissier et al (2009)
3.5 y, M, French
Varol et al (2011)
33 y, F, Turkish
Hernandez-Alfaro et al
(2011)
18 y, F, Spanish
Raposo-Amaral et al
(current study)
13 y, F, Brazilian
Craniodentofacial and Extremity
Clinical Findings
Radiographic Findings
Frontal bossing, bilateral proptosis of
the eyes, gross midface hypoplasia,
beaked nose, small
mandible, marked retrogenia, and
class III malocclusion
Bulbous deformity of all the terminal
phalanges of the fingers and toes
and short stature
Midfacial hypoplasia, exophthalmos, blue
sclera, and class III malocclusion
Short stature, short fingers and toes, and
dystrophic clavicles
Severe upper airway obstruction with
apnea, retrognathia, glossoptosis,
beaked nose, high forehead, large
fontanelles, and sagittal sutures
Short spoon-shaped fingers with
overriding nails and wrinkles
Midfacial hypoplasia, slight retrognathia,
exophthalmos, and frontal bossing
Dwarfism, clavicular dysplasia,
dystrophic fingernails, and
brachydactyly
X-ray: skullV sclerosis of skull base, patent
frontotemporal and parietooccipital sutures;
faceV rudimentary maxillary sinuses
and obtuse gonial angles of mandible;
handsVshort terminal phalanges and
resorption of the terminal phalanges
Advancement of maxilla, mandible
with inverted osteotomy, and
genioplasty with bone grafting
Lateral cephalogram: maxillary hypoplasia
and obtuse mandibular angle
Bimaxillary distraction osteogenesis
with rigid external device
CT: hypoplastic mandible and maxilla,
flattened mandibular angles, and
bilateral exophthalmia
Costochondral rib grafting to enlarge
pharyngeal airway
Cephalometric analysis: reduced facial
height and absence of gonial angle
Rx: intraoralVlower third molars,
2 lower and 2 upper premolars were
developmentally absent, and height and
width of the ramus and height of the
body of the mandible were reduced;
handsVacroosteolysis of the terminal
phalanges and fractures of metatarsals
on both sides
Cone beam CT scan: distorted facial
architecture with abnormally small
facial bones
Bimaxillary distraction osteogenesis
with rigid external device
CT: patency of coronal and lambdoid
cranial sutures and obtuse angle of
the mandible
X ray: small airway pharyngeal space
Subcranial Le Fort III advancement
with internal distraction osteogenesis
Brachycephaly, open cranial sutures and
fontanelle, maxillary and mandibular
hypoplasia, rhinomegaly, and class II
malocclusion
Short stature, clavicular and phalangeal
dysplasia
Midfacial hypoplasia, exorbitism,
obstructive sleep apnea, and
class III malocclusion
Short stature and acroosteolysis
Craniofacial Surgical Technique
Mandibular advancement with bilateral
sagittal split osteotomy, maxillary
advancement with Le Fort 1
osteotomy, and vertical sagittal
augmentation genioplasty with
synthetic bone graft
F indicates female; M, male; CT, computed tomography.
* 2013 Mutaz B. Habal, MD
Copyright © 2013 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
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Raposo-Amaral et al
of the type of osteotomy used. Reviewing the literature, we found
little information regarding recommended periods for latency, activation, and consolidation for this particular disease; and so we
adopted a traditional distraction osteogenesis protocol,8,9 reasoning
that this would allow gradual bone regeneration and sufficient bone
stability. Indeed, 2 years after surgery, the patient had sufficient
stability of the midface, complete remission of the sleep apnea, and
resolution of symptoms related to exorbitism such as corneal exposure, ocular redness, and ocular pain.
For this particular disease, we feel that subcranial Le Fort III
advancement is able to correct more craniofacial dysmorphisms of
pcynodysotosis than orthognatic procedures. Moreover, it produces
a more stable result with less surgical morbidity in comparison to
acute advancements involving bone grafts and rigid fixation.
In conclusion, this is the first report on the successful use of
subcranial Le Fort III midface advancement with distraction osteogenesis for craniofacial reconstruction of a pycnodysostosis patient.
A subcranial Le Fort III with a previously described distraction
osteogenesis protocol was sufficient to provide bone stability to
the craniofacial skeleton for this particular patient. However, further
studies with a larger cohort may analyze the average individual bone
physiologic response to this operation. Because pycnodysostosis is
a very rare disease, a multicenter study may be required.
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* 2013 Mutaz B. Habal, MD
Copyright © 2013 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.