Journal of Cranio-Maxillo-Facial Surgery 47 (2019) 420e430

Contents lists available at ScienceDirect

Journal of Cranio-Maxillo-Facial Surgery

journal homepage: www.jcmfs.com

Midface correction in patients with Crouzon syndrome is Le Fort III

distraction osteogenesis with a rigid external distraction device the
gold standard?
Michael Engel 1, Moritz Berger 1, Jürgen Hoffmann, Reinald Kühle, Thomas Rückschloss,
Oliver Ristow, Christian Freudlsperger, Katinka Kansy*
Department of Cranio- and Maxillofacial Surgery, Heidelberg University Hospital, Heidelberg, Germany

a r t i c l e i n f o a b s t r a c t

Article history:
Introduction: Le Fort III distraction osteogenesis with a rigid external distraction device is a powerful
Paper received 23 April 2018
procedure to correct both exorbitism and impaired airways in faciocraniosynostosis. The aim of this
Accepted 29 November 2018
Available online 31 December 2018 study was to investigate treatment effect, perioperative parameters and volumetric outcomes after Le
Fort III distraction osteogenesis in patients with Crouzon syndrome in a retrospective study design and to
explore potential strengths and weaknesses of this procedure.
Keywords:
Crouzon syndrome Materials and methods: From June 2013 to February 2015, a total of nine children with Crouzon syndrome
Le Fort III osteotomy underwent Le Fort III distraction osteogenesis with a rigid external distraction device (RED device, KLS
Distraction osteogenesis Martin, Tuttlingen, Germany). Along with perioperative parameters, sleep study reports, traditional
cephalometric analysis, three-dimensional imaging and photographs were evaluated for severity of
disease and therapeutic effect and structural and functional changes of the upper airway preoperatively,
after device removal and one year postoperatively.
Results: Surgery for Le Fort III distraction was performed at a median age of 12.5 years (SD 2.5 months)
with an average weight of 43.0 kg (SD 12.9 kg). Mean estimated blood loss was 535.7 ml (SD 128.1 ml),
not requiring any red blood cell transfusions. Mean duration of surgery was 240 min (SD 30.6min),
average hospital stay eight days (SD 0.5 days) with a planned median ICU stay of 1.7 days (SD 0.4 days)
for all patients.
There were a total of five minor complications. Exorbitism and Angle class III malocclusions were
corrected in all patients. No patient showed velopharyngeal problems postoperatively. The average
amount of distraction was 18.4 mm (14e26 mm). Average length of the distraction period was 18.3 days
(SD 0.4 days), with a total distraction plus consolidation time of three months (SD 0.25 months). In two
patients, vector correction was performed during distraction. A counterclockwise movement despite
vector correction, clinically resulting in an open bite, was observed in one of these two patients. Eight of
the nine patients showed a frontal overbite at the end of the distraction period.
Cephalometric analysis revealed a significant increase of Sella-Nasion-Point A angle (SNA) from 76.0

(þ/ 2.9; T1) to 86.0
(þ/ 3.4; T2) (p ¼ 0.006) and growth-related point A-Nasion-point B angle (ANB)
from 4.8
(þ/3.7) to 5.7
(þ/4.8) (p ¼ 0.001) from preoperatively to device removal and stable re-
sults one year postoperatively.
Upper airway structure and respiratory function were improved clinically after the Le Fort III DO
treatment in all cases with an average posterior airway space increase from 3199 mm3 (þ/ 229.6 mm3)
to 8917,7 ml (þ/415.1 mm3) (T1 to T2).
Surgical outcome was judged good to excellent both by patients and families and the craniofacial
team.
Conclusion: Le Fort III DO with a rigid external distraction device in patients with Crouzon syndrome is a
powerful and reliable surgical procedure that reliably produces a more significant change of appearance
than most other single procedures routinely performed by craniofacial surgeons. It effectively treated

* Corresponding author. Department of Oral and Maxillofacial Surgery University

Hospital Heidelberg Im Neuenheimer Feld 400, 69120 Heidelberg, Germany.
E-mail address: katinka.kansy@med.uni-heidelberg.de (K. Kansy).
1
Equally first, both authors contributed equally to the paper.

https://doi.org/10.1016/j.jcms.2018.11.028
1010-5182/© 2018 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.
 M. Engel et al. / Journal of Cranio-Maxillo-Facial Surgery 47 (2019) 420e430 421

sleep apnea in the affected patients. In our collective, the maxilla remained stable after advancement
without any relapse, but there was no subsequent anterior growth on one year follow-up. Careful vector
planning was able to avoid frontal open bite in eight patients. Complication rates were acceptably low
and patients’ functional and esthetic outcome was high.
© 2018 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights
reserved.

1. Introduction In contrast to these reports, the purpose of our study was to

evaluate the operative outcome of the uniform treatment concept
Crouzon syndrome is a rare autosomal dominant disorder with a of LFIII DO with a rigid external distraction device in a homogenous
prevalence of 16.5/million births and characterized by faciocra- group of patients with Crouzon syndrome.
niostenosis due to craniosynostosis (Bannink et al., 2010; Kuroda
et al., 2011; Arnaud and Di Rocco, 2012). 2. Materials and methods
Genetic mapping of these syndromes shows that mutations in
fibroblast growth factor receptor 2 (FGFR2) are the cause for cra- This monocentric retrospective study was approved by the local
niosynostosis in most patients (Hollway et al., 1997). Ethics Committee (Ethics number S-237/2009) and carried out
Reduced intracranial volume associated with intracranial pres- according to the Declaration of Helsinki. Written informed consent
sure and midfacial hypoplasia are known as the typical pathogno- was obtained from the parents of all patients.
monic symptoms (Kuroda et al., 2011; Arnaud and Di Rocco, 2012) Between June 2013 and July 2015, all children with Crouzon
also present in Crouzon syndrome and requiring surgical treat- syndrome and faciostenosis, who were treated with a rigid external
ment. Furthermore, there is little anteroposterior midfacial growth distraction device for LFIII DO as described by Fearon et al. (Fearon,
overtime without intervention (Wery et al., 2015). 2001) at our hospital, were included in the study.
Midfacial hypoplasia presents with several clinical problems, Surgical approach to the facial skeleton was obtained by
most notably at the level of the airway, orbits, occlusion and facial bicoronal incision and followed by subperiostal dissection to gain
esthetics with their associated psychosocial problems. Crouzon access to the orbits. Thereafter, the classic osteotomies (orbital
patients are at high risk for upper airway obstruction and are floor, roof and walls, zygoma) were made with separation of the
predisposed for narrowed dimensions of the posterior airway space pterygomaxillary junction either from the coronal approach or
(PAS). through a gingivobuccal access. Particular care was put on obtain-
A high percentage of patients with syndromic craniosynostosis ing clear osteotomy lines. Rowe's forceps were used to mobilize the
develop OSAS and need airway intervention at some time (Boston LFIII segment. The rigid external distraction device (RED device, KLS
and Rutter, 2003; Hoeve et al., 2003; Nout et al., 2008). Martin, Tuttlingen, Germany) was fixed in the established manner
The main objectives of surgical treatment in this complex syn- by screw fixation of four to five bilateral pins into the parietal
dromic craniosynostosis remain the prevention of cerebral damage bones, taking the quality of the local bone into account. A total of
secondary to craniosynostosis and the correction of midface ret- four distraction wires were attached transcutaneously to plates
rusion with the associated problems of exorbitism and upper air- fixed next to both piriform apertures and to two special maxillary
ways impairment (Fearon, 2001; Bannink et al., 2010; Arnaud and retention plates (Fig. 1). All operative procedures were performed
Di Rocco, 2012). by the same surgeon (M.E.).
The traditional surgical procedure for correcting midfacial hy- All patients were hospitalized for seven days regardless of age.
poplasia is a Le Fort III (LFIII) osteotomy. While it was first described Patients were admitted to intensive care unit (ICU) for the first
by Gillies and Harrison in 1949 (Gillies and Harrison, 1950; Warren 24e48 h after surgery. DO was initiated one week postoperatively.
et al., 2012), it then took 20 more years and refinements by Tessier The rate of distraction was 1 mm/day in two daily activations.
to be performed on a greater number of adults (Tessier, 1967, 1971). The RED device was activated such that the location of the main
Advances in pediatric esthesia and intensive care treatment vector of force was 50e60% above the occlusal plane as measured
allowed for the feasibility of this procedure in children in the 1980s from the upper incisal point to the nasion. The direction of the
(McCarthy et al., 1984). distraction force vector was also maintained parallel to the occlusal
In 1993, Cohen et al. first successfully combined LFIII osteotomy plane (Fig. 1).
with distraction osteogenesis (DO) in a 4-year old boy (Cohen The duration of DO depended on the desired advancement.
et al., 1995). Since then, several reports have been published During the distraction period, vector modifications took place
dealing with DO on the LFIII level (Polley et al., 1995; Cohen et al., when necessary. A consolidation period of three months was
1997; Britto et al., 1998; Cedars et al., 1999). As experience grew planned.
with the technique, research focused on developing new internal Sleep study reports, traditional cephalometric analysis (Figs. 2
and external devices and optimizing DO protocols (Nout et al., and 3), three-dimensional CT imaging/or CBCT (Figs. 4 and 5) and
2008). photographs (Figs. 6e8) were reviewed to quantify the degree of
Although there are both older and more recent reviews on severity preoperatively and the effect of the surgical procedure
craniofacial distraction osteogenesis in general (Swennen et al., postoperatively (see Fig. 9).
2001) and in syndromic craniosynostosis (Al-Namnam et al., Cephalometric radiographs were obtained at three points of
2018), the evidence of treatment outcomes in the rare condition time: preoperatively (T1), at device removal (T2), and at 1-year
of Crouzon syndrome are sparse. Even within the two compre- follow-up (T3). All three radiographs were superimposed at the
hensive reviews, the total number of Crouzon patients is small and anterior cranial base and differences of point A and point B on the
within the reviews, both studies with various different treatment x- and y-axis were calculated. The x-axis was parallel to the
concepts and studies with mixed patient populations (Crouzon, Frankfurt horizontal plane, and the y-axis was perpendicular to x-
Apert and Pfeiffer syndrome) have been included in the analysis. axis at Sella (S) in this coordinate system.
422 M. Engel et al. / Journal of Cranio-Maxillo-Facial Surgery 47 (2019) 420e430

Fig. 1. Patient 1 with RED II distractor during the activation period (fontal view ¼ left picture; lateral view ¼ right picture).

Fig. 2. Lateral cephalometric radiographs of patient 1 at three time intervals: preoperatively (T1), at device removal (T2), and at 1-year follow-up (T3).

Fig. 3. Lateral view showing the ROI for calculation of the PAS (patient 3).

Paired t tests were used to evaluate stability of postoperative Patients primarily presenting at our department received CBCT
measurements (Sella-Nasion-Point A angle (SNA); Point A-Nasion- imaging for pre- and postoperative analysis. In these cases, three-
Point B Angle (ANB)) (Table 1). dimensional imaging allowed for three-dimensional analysis of
For five patients, three-dimensional CT images or CBCTs were midface movement and posterior airway space superior to con-
available at two points of time: preoperatively (T1) and at device ventional lateral radiographs.
removal (T2). These images were visualized and analyzed by one iPlan® Cranial was used for the measurement of the amount of
investigator (M.B.) using the software iPlan® Cranial (Brainlab, three-dimensional midface advancement. Sicat Air® was used for
Feldkirchen, Germany) and Sicat Air® (Deutschland). Although the evaluation of upper airway parameters.
three-dimensional imaging was not performed routinely in all After importation to Sicat Air® software, Dicom datasets were
patients, some patients required CT imaging for an intracranial oriented based on the following reference planes: Frankfurt hori-
shunt. Others presented with conventional radiographs and no zontal plane (constructed on Po, Orr and Orl), midsagittal plane
additional images were performed to minimize radiation exposure. (perpendicular to Frankfurt horizontal plane, passing through Na
 M. Engel et al. / Journal of Cranio-Maxillo-Facial Surgery 47 (2019) 420e430 423

Fig. 4. 3D illustration of the PAS in a (a) pre- (T1) and (b) postoperative dataset (T2) (patient 3).

Fig. 5. Patient 1: A 9-year-old boy with Crouzon syndrome seen preoperatively (left), after removing the RED distractor (middle) and 12 months postoperatively (right).

and Ba), and coronal plane (perpendicular to Frankfurt horizontal outcome of surgery was considered “excellent” if both parents and
plane and midsagittal plane). surgeon were satisfied, “good” if only the parents were satisfied and
In the next step, the region of interest (ROI) for the posterior “poor” if both the parents and the physician were not satisfied.
airway space (PAS) segmentation was set (Kim et al., 2010). Two Student t-test was used to compare continuous variables and p-
reproducible marker points were placed at the posterior nasal spine values <0.05 were considered as significant. All statistical analyses
and the most anterior cranial point of the fourth vertebral body were performed using SPSS for Windows version 12.0 (SPSS, Chi-
(Fig. 4). Afterwards, Sicat Air® used an automatic segmentation al- cago, USA).
gorithm computing all air-filled areas within the ROI, clearly demar-
cating them from bony-tissue and soft-tissue structures, thus 3. Results
processing a volumetric analysis of the defined airways. All PAS vol-
umes were calculated in cubic millimeters (Ristow et al., 2018) (Fig. 5). From June 2013 to February 2015, in this retrospective setting, a
Furthermore, sex, weight, age at surgery, complication rate total of nine children including six (66.7%) boys and three (33.3%)
(intra- and postoperatively), duration of surgical procedure (cut- girls were identified from the medical records with the diagnosis of
tingesuture time), hemoglobin values (pre-,-and postoperatively), Crouzon syndrome and underwent LFIII DO with a rigid external
estimated blood loss, amount of RBC transfusion and length of distraction device (RED II device/KLS Martin) to treat their facios-
hospital stay were recorded. tenosis at a median age of 12.5 years (SD 2.5 years). Due to stan-
We employed the classification of Whitaker and associates to dardized digital documentation, complete patient data could be
evaluate the surgical results (Whitaker et al., 1987). The esthetic retrieved from all patient files. For five patients, pre- and
424 M. Engel et al. / Journal of Cranio-Maxillo-Facial Surgery 47 (2019) 420e430

Fig. 6. Patient 2: A 10-year-old girl with Crouzon syndrome seen preoperatively (left), after removing the RED distractor (middle) and 12 months postoperatively (right).

Fig. 7. Definition of occlusal situation after removal of distraction device (a: circular open (patient 4), b: premolar open (patient 5), c. closed (patient 6)).

postoperative CTs or CBCTs were available (Table 2). All of these the consolidation period and had to be re-fixated operatively. Eight
patients had had craniofacial reconstruction by standardized of nine patients had a frontal overbite at the end of the distraction
fronto-orbital advancement in the first year of life as the first part of period. Due to an extensive counterclockwise rotation of the mid-
a two-step approach to correct the faciocraniostenosis. One patient face resulting in a frontal open bite, a vector modification was
had undergone a previous conventional LFIII osteotomy (patient 3). performed in two patients during the distraction period. Correction
All patients in this series tolerated the external devices well. was successful in one patient. In the other patient (patient 3), an
Exorbitism and angle class III malocclusions were corrected in all open bite in the frontal and premolar region was present at the end
cases (Figs. 6e8, Figs 10 and 11). Average weight at time of surgery of the distraction period (Fig. 3a).
was 43.0 kg (SD 12.9 kg). Mean estimated blood loss was 535.7 ml Two of our patients suffered from transient problems with
(SD 128.1 ml). Red blood cell transfusion was not necessary in our mastication postoperatively due to dental arch mismatch in a class
study population. Average hemoglobin value was 13.6 mg/dl (SD II relationship caused by planned overcorrection. Chewing
0.8 mg/dl) preoperatively and 9.5 mg/dl (SD 0.7 mg/dl) post- normalized after one year in both patients (Figs. 10 and 11). Eight of
operatively. Mean duration of surgery for all patients was 240 min nine patients had orthodontic therapy before and during, and all
(SD 30.6 min). Average hospital stay was 8 days (SD 0.5 days) with a patients had additional orthodontic treatment after LF III DO
planned median ICU stay of 1.7 days (SD 0.4 days) for all patients. (Table 2).
Average length of distraction period was 18.3 days (SD 0.4 days). No patient in our series showed any velopharyngeal problems
Total duration of distractor period (distraction and consolidation postoperatively.
time) was three months (SD 0.25 months). All patients had com- All patients in our series had cephalometric radiographs ob-
plete distraction. Detailed patient data is given in Table 2. tained at our defined measuring points (preoperatively (T1), at
No live threatening complications were observed intra- or device removal (T2), and at one-year follow-up (T3)). The average
postoperatively. There were a total of five complications. Three of amount of distraction, as measured by the number of turns made
our patients had an infection in the placement area of the distractor on the distractor, was 18.4 mm (range 14e26 mm).
pins (Fig. 11). One patient showed loosening of a distractor pin. In Cephalometric analysis revealed that the SNA angle increased
one case the whole external distraction device became loose during significantly from 76.0
(þ/ 2.9; T1) to 86.0
(þ/ 3.4; T2) degrees
 M. Engel et al. / Journal of Cranio-Maxillo-Facial Surgery 47 (2019) 420e430 425

Fig. 8. Demonstration of the distraction distance using iPlan? Cranial in patient 1: preoperatively (T1/purple) and at device removal (T2/green).

(p ¼ 0.006). The average point ANB angle was corrected from 4.8
Seven children in this series experienced a very good esthetic
(þ/3.7) to 5.7
(þ/4.8) (T1 to T2; p ¼ 0.001). correction of their deformities, as judged by both their families and
SNA angle was stable in the one year follow up examination the craniofacial team. In the other two cases, the family was pleased
(T3). Paired t tests revealed no statistically significant relapse from with the outcome, although the craniofacial team still identified
T2 to T3. mild deficits (good outcome).
ANB angle decreased from 5.7
(þ/4.8) to 5.1
(þ/3.5) from
device removal (T2) to follow-up 1 year postoperatively (T3),
however differences were not significant (p > 0.05). 4. Discussion
Following DO, no additional forward maxillary growth was
observed (per lateral cephalogram analysis) up to one year post- LFIII DO has been described as the treatment of choice for
operatively (Table 1; Figs. 2 and 3). midface advancement by various authors in the literature, espe-
Upper airway structure and respiratory function improved clini- cially in younger patients, severe cases and associated syndromic
cally after LFIII DO treatment in all cases. In four patients, pre- and craniosynostosis. With this technique, advancements of more than
postoperative (T1 and T2) CT/or CBCT scans were available to mea- 30 mm are possible (Shetye et al., 2010; Fearon, 2001, 2005; Xu
sure the increase of PAS (Fig. 5). The average PAS increased from et al., 2009; Meazzini et al., 2012), while conventional LFIII
3199 mm3 (þ- 229.6 mm3) to 8917.7 ml (þ-415.1mm3) (T1 to T2). osteotomy without distraction limits safe and reliable advancement
No patient in this series was tracheostomy-dependent before distances to a maximum of 17e20 mm (Toth et al., 1998; Cedars
surgery. Seven patients had been suffering from nocturnal snoring et al., 1999; Saltaji et al., 2014) and may require bone transplants.
without any signs of apnea/OSAS. Snoring disappeared in six pa- Ideal treatment age in the literature is between eight and twelve
tients and decreased in one patient after midface distraction. Two years or after the age of 18 (Shetye et al., 2010; Wery et al., 2015).
patients with preoperative evidence of OSAS had to be evaluated by Distraction osteogenesis in syndromic patients has replaced
overnight polysomnography (PSG). PSG showed that one patient conventional LFIII advancement in almost all cases. This is due to
had moderate and a second patient had severe OSAS preopera- the fact that DO allows for greater advancement distances, more
tively. Both were treated with a nocturnal breathing mask and stable long-term results (Shetye et al., 2010), less bone gaps and
continuous positive airway pressure (cPAP). Postoperatively, the decreased risk of perioperative complications due to gradual soft
situation in both patients improved significantly: In the patient tissue expansion. Since its introduction in craniomaxillofacial sur-
with severe OSAS, the respiratory disturbance index (RDI) was gery, DO has been utilized for a multitude of indications and has
reduced from 100 episodes per hour to less than five episodes per opened up a whole new field of therapeutic options. DO is a ver-
hour. In the case of moderate OSAS the respiratory disturbance satile and reliable way of bone generation, especially in younger
index (RDI) was reduced from 25 episodes per hour to less than five patients. However, well-designed osteotomy lines, correct dis-
episodes per hour. Postoperative sleep studies demonstrated that tractor placement and vector selection are important for treatment
midface distraction with external devices alleviated OSAS in both success.
patients. In accordance with these recommendations, LFIII DO was
According to the classification of Whitaker, seven patients had a considered the best treatment concept for our collective of syn-
Class 1 outcome, with excellent surgical results. Two patients were dromic Crouzon patients with an average advancement of 18.4 mm
defined as Class 2 outcome with a good outcome postoperatively. and a mean age of 12.5 years.
426 M. Engel et al. / Journal of Cranio-Maxillo-Facial Surgery 47 (2019) 420e430

When performing LFIII DO, a number of challenges and pitfalls

have been described:
When performing LFIII DO at a young age, overcompensation of
maxillary advancement should be planned to compensate for the
lack of maxillary growth postoperatively. This could be confirmed
by our analysis with a good maxillary advancement from T0 to T1
but no further maxillary growth thereafter (T1 to T2) and a stable
ANB angle in our study population at one year follow up exami-
nation without significant relapse of cephalometric measurements
on lateral cephalogram analysis.
This is in line with the findings of Shetye et al. comparing the
stability of the LFIII versus LFIII-DO procedures and a mild relapse
in the LFIII group with excellent stability in the LFIII-DO group, even
after relatively greater forward advancements one year post-
operatively (Shetye et al., 2010), similar to results by Bradley et al.
(2006). The same was true for the five year follow up results of
Patel et al. with stable maxillary position after LFIII advancement
with distraction, minimal advancement along the x axis and more
growth along the y axis (Patel et al., 2017) and in line with the few
other reports on long-term stability with minimal or no relapse of
the midface segment after LFIII DO (Fearon, 2005; Lee et al., 2012;
Meazzini et al., 2012; Iannetti et al., 2012). One important factor
may be that gradually expanding the soft tissue might reduce the
elastic forces acting on the maxilla (Fearon, 2005) in contrast to
conventional LFIII advancement.
The results of a small heterogeneous cohort of Hu et al. (2017)
show less favorable results for Monobloc frontofacial advance-
ment DO compared with LFIII DO with a depressed nose in long-
term follow-up especially in very young patients on four year
follow-up.
Increased soft tissue tension at the level of the upper midface in
comparison to the lower midface during distraction may also
contribute to the common phenomenon of counterclockwise
rotation of the mandible in LFIII DO (Shetye et al., 2009; Figueroa
et al., 2010; Roldan et al., 2011; Bouw et al., 2015) regardless of
mode of anchorage (Bouw et al., 2015). However, Lee et al. argue
that counterclockwise rotation is due to the main distractor force of
external devices and can be overcome by a combination of internal
and external distractors (Lee et al., 2012).
In our cohort, we were able to achieve a frontal overbite in eight
of nine patients at the end of the distraction period respecting the
recommendations of Shetye et al. with a force vector located at 55%
(50e60%) of the distance measured from the incisal edge to the
nasion and parallel to the occlusal plane (Shetye et al., 2009). In two
of our patients, we had to perform a change of vector during the
distraction period, which led to successful bite correction in one
Fig. 9. Dental situation of patient 1 preoperatively (above), after removing the RED patient but resulted in a frontal open bite in the other patient
distractor (middle) and 12 months postoperatively (below). nevertheless. As this patient had already undergone a conventional
LFIII osteotomy in the past, additional scarring may have been one
factor for the failure of sufficient vector correction. Seven of the
On the other hand, adult patients with mild midface hypoplasia nine patients did not require any vector correction. In addition, a
may benefit from conventional LFIII osteotomy due to normal oc- total of five distractor-related complications (three pin infections,
clusion postoperatively, shorter treatment time and the absence of a one pin loosening and one distractor loosening and refixation)
DO device and associated psychosocial problems (Saltaji et al., 2014). reflect a relatively high complication rate of external distraction

Table 1
Changes of SNA and ANB angle within the cohort over time (mean and standard deviation).

Norm value T1 T2 T3 D T1,T2 D T1,T3 D T2,T3

SNA 81.0
(þ/ 3.0) 76
(þ/2.9) 86
(þ/3.4) 85.7
(þ/2.9) 10
(þ/1.9) p ¼ 0.006a 9.8
(þ/1.1) p ¼ 0.001a 0
(þ/1.2)
NSb
ANB 2
(þ/2) 4.8
(þ/3.7) 5.7
(þ/4.8) 5.1
(þ/3.5) 10.4
(þ/1.8) p ¼ 0.001a 8.0
(þ/5.3) p ¼ 0.006a 0.1
(þ/1.8)
NSb
a
Significant change pre-/postoperatively.
b
NS ¼ not significant, stable result postoperatively, no significant difference between values at T2 and T3.
 M. Engel et al. / Journal of Cranio-Maxillo-Facial Surgery 47 (2019) 420e430 427

Table 2
Patient characteristics; A: general, functional and perioperative data, B: cephalometric and airway space data.

Patient Sex Age at Weight Height BMI FOA Snoring Tracheostomy Duration of HB HB Estimated hospital RBC-transfusion intra-op
surgery (kg) (m) pre-op preop surgery (min) pre-op post-op blood loss stay (days) complications

1 m 10.5 27 1.58 13.2 y y n 230 13.6 8.8 470 7 n n

2 f 10.4 26 1.29 15.5 y y n 260 13.2 8.3 525 7 n n
3 f 13.2 46 1.44 22.2 y OSAS n 180 15.8 10.8 630 8 n n
4 m 11.4 60 1.58 24.0 y y n 210 13.2 9.5 450 8 n n
5 m 11 41 1.49 18.5 y y n 270 13.3 9.6 330 7 n n
6 m 14.8 56 1.68 19.8 y OSAS n 245 13 10 700 8 n n
7 m 16.8 48 1.63 18.5 y y n 275 13.1 10 730 7 n n
8 m 9.6 53 1.47 24.5 y y n 255 14 9 510 8 n n
9 f 14.4 30 1.44 14.5 y y n 235 13.6 9.8 470 8 n n

Patient Distraction post-op velopharyngeal Occlusal situation after removing retention CT/CBCT SNA SNA SNA ANB ANB ANB PAS PAS
period complications problems/ the distraction device period pre-and (T1) (T2) (T3) (T1) (T2) (T3) mm2 mm2
(days) insufficiency (months) post (T1) (T2)
Frontal Premolar Molar
region region region

1 26 local pin infection n overbite Non-occlusion closed 3,3 y 72 83 83 2 10 8 3090 9347

2 14 n n overbite Non-occlusion closed 2,5 n 73 81 81 3 4 2
3 16 local pin infection n overbite Non-occlusion closed 2,9 y 80 92 90 1 10 8 3541 8456
4 19 n n open bite open bite closed 3,1 n 76 88 87 6 7 6
5 18 distractor refixation n overbite Non-occlusion closed 3 n 73 83 83 3 9 8
6 22 pin loosening n overbite closed closed 3 n 78 85 87 11 3 0
7 15 local pin infection n overbite closed closed 3,3 y 75 87 86 6 6 6 3199 8918
8 15 n n overbite Non-occlusion closed 3,1 y 79 89 88 1 9 8 3115 8690
9 21 n n overbite closed closed 3,2 y 78 86 87 10 1 0 3050 9178

devices. Therefore, the benefit of external distraction devices re- Latency period and rate of distraction of our study population
mains questionable. However, pin loosening, distractor loosening were comparable to most published studies. Saltaji and colleagues
and pin infection may also occur in internal devices. Furthermore, published a systematic review in 2014 about the results in LFIII DO
due to successful vector correction in one patient, the external versus the conventional LFIII osteotomy in correction of syndromic
distraction device was able to avoid a LeFortI osteotomy procedure midfacial hypoplasia (Saltaji et al., 2014). In this publication, the
at an older age for this patient. general latency period was 5 days (range 2e7), with a rate of
Within the literature, Meling et al. favor the use of external distraction of 1 mm/day, except for the study by Hopper et al., in
distraction devices due to shorter operating time and the possibility which patients younger than 6 years underwent a distraction rate
of three-dimensional control (Meling et al., 2011). of 1.5/day (Hopper et al., 2010).
Sinha et al. showed good results following internal LFI/II midface In most studies, consolidation period ranged from 4 to 12
distraction, however, their average distraction distance was mark- weeks (Saltaji et al., 2014). With respect to LFIII DO, the study by
edly shorter (13.3 mm) than in our cohort (Sinha et al., 2011). Arnaud et al. proposed that a short consolidation period might
In their description of an intraoral device, Burstein et al. again contribute to incomplete ossification and persistent elasticity of
discuss two potential downsides of internal devices: the limited the soft tissue and hence an increased risk of relapse. They high-
amount of distraction compared to external devices and the po- lighted the importance of adequate consolidation periods to help
tential for traditional orthognathic surgery at skeletal maturity due prevent relapse (Arnaud et al., 2007; Lee et al., 2012). We are in
to lack of vector correction (Burstein et al., 2015). The same is true line with Arnaud et al. and prefer a consolidation period of 10e12
for the cohort of Nakajima et al. who showed successful application weeks.
of an internal device but reported the problem of frontal open bites In contrast to these studies, Hopper et al. reported relative sta-
at the end of the distraction period (Nakajima et al., 2012) and the bility in the maxilla in all patients, regardless of the consolidation
results of Satoh et al. with internal distraction resulting in a frontal duration (Hopper et al., 2010). The clearly conflicting conclusions
open bite in all of their exemplary cases (Satoh et al., 2006). might have resulted from differences in the ‘‘pterygomaxillary
The study by Riediger and Poukens shows the successful osteotomy bone formation’’ or, possibly, the small number of pa-
application of delicate internal devices in LFIII DO, however, they do tients in the latter study. Ergo, association between stability and
not present occlusal results in their cohort and the only presented consolidation period could not be confirmed (Saltaji et al., 2014).
case shows a Class III occlusion at the end of the distraction period It has also been postulated that both LFIII and LFIII DO relapse
(Riediger and Poukens, 2003). might be related to inadequate postoperative fixation or palatal
In their review of distraction osteogenesis in syndromic cra- scarring that has occurred from previous operations (Kapucu et al.,
niosynostosis, Al-Namnam et al. found a high rate of counter- 1996; Meazzini et al., 2005).
clockwise rotation following LFIII DO with external devices in However, not all studies have confirmed that it plays a key role
comparison to internal devices (Al-Namnam et al., 2018). However, in postoperative relapse after LFIII DO.
with a closer look at their analysis, only a few results on occlusal No live-threatening complications were observed intra- or
outcome are given in the cited publications using internal devices. postoperatively in our series of nine Crouzon patients. There were a
Furthermore, the example of our cohort shows that taking this total of five complications. Three of our patients had an infection in
movement into account when planning the distraction vector can the area where the distractor pins were placed. One patient showed
overcome this tendency in most cases. In addition, they found that loosening of a distractor pin. In one case loosening of the whole
greater advancements are feasible with internal devices (Al- external distraction device was observed during the consolidation
Namnam et al., 2018). This again does not correspond with the period and operative re-fixation became necessary. With respect to
results of our cohort where distraction distances identical to their LFIII DO, multiple investigators have reported minor or no post-
analysis of internal devices were achieved. operative complications.
428 M. Engel et al. / Journal of Cranio-Maxillo-Facial Surgery 47 (2019) 420e430

Fig. 11. Local pin infection during the retention period (patient 3).

intracranial migration of halofixation pins, fracture of the

zygomatico-maxillary junction, and intraoperative fragment
disjunction (Swennen et al., 2000; Saltaji et al., 2014). Fearon et al.
also reported incomplete distraction in three patients and asym-
metric advancement in two patients, perhaps related to a ‘‘unilat-
eral incomplete downfracture.’’ (Fearon, 2005; Saltaji et al., 2014).
All of our patients had complete distraction. We are convinced that
clear osteotomy lines and a proper down fracture can avoid
incomplete distraction.
After LFIII advancement, there is an increased risk that children
may develop velopharyngeal incompetence (Fearon, 2005). No
patient in our series showed clinical signs of velopharyngeal
problems postoperatively (transient or permanent). In a series of
eleven patients who were followed after LFIII using internal
distraction, Cedars et al. identified only one patient that had tran-
sient velopharyngeal incompetence (Cedars et al., 1999). In a large
series of Fearon using RED distractors after a LFIII, only two patients
developed transient velopharyngeal incompetence; both sponta-
neously improved within six weeks without any therapy. Despite
an average measured maxillary advancement of just less than 2 cm,
no patients in this series developed permanent velopharyngeal
incompetence (Fearon, 2005).
At the same time, early surgical intervention of midfacial hy-
poplasia is indicated to treat OSAS associated with reduced airway
space due to a posteriorly positioned midface (Shetye et al., 2010).
Obstructive sleep apnea is common in patients with craniofacial
abnormalities, especially in syndromic craniosynostosis like Crou-
zon syndrome (Ponniah et al., 2008; Witherow et al., 2008; Xu
et al., 2009). This may remain undetected in some patients, but
Fig. 10. Dental situation of patient 2 preoperatively (above), after removing the RED nevertheless 50% of patients with syndromic craniosynostosis
distractor (middle) and 12 months postoperatively (below).
develop OSAS and need airway intervention at some time (Hoeve
et al., 2003; Pijpers et al., 2004). Some severe cases may even
However, the LFIII is a high risk operation that can result in need tracheotomy to alleviate airway obstruction. However, tra-
complications (Cedars et al., 1999; Ridgway et al., 2011). A number cheotomy has a high complication rate (Moore, 1993; Mahadevan
of different and more severe complications can be found in the et al., 2007; Xu et al., 2009). No patient in this series was
literature. These complications vary from cerebrospinal fluid tracheostomy-dependent before surgery. In our collective, two
leakage to meningitis and infections (Bradley et al., 2006). Other patients had preoperative evidence of OSAS which was significantly
complications reviewed by Nout et al. included cutting the alleviated by LFIII DO with a significant improvement of PAS in all
infraorbital nerve, strabismus, ptosis, partial anosmia, zygoma patients of the cohort and markedly improved sleep studies post-
fracture during mobilization, partial exposure of the nasal bone operatively in the two patients with OSAS in line with the findings
graft, respiratory distress requiring tracheotomy, subgaleal hema- of Fearon and Xu (Fearon, 2005; Xu et al., 2009) Furthermore,
toma, cerebrospinal fluid leakage, and visual loss after retro-orbital snoring disappeared in six of our patients and decreased in one
hemorrhage (Nout et al., 2008; Saltaji et al., 2014). patient after midface distraction.
Swennen et al. reported a number of complications after LFIII Until now a lot of studies have proven that craniofacial
DO, including pin loosening, frame migration, traumatic injury, morphology affects the extent of the pharyngeal airway space
 M. Engel et al. / Journal of Cranio-Maxillo-Facial Surgery 47 (2019) 420e430 429

(Alves et al., 2008; Park et al., 2010; Stellzig-Eisenhauer and Meyer- complications, while one patient had a benefit from vector
Marcotty, 2010). Numerous studies have demonstrated that a correction.
combined orthodonticeorthognathic treatment highly influences
the upper airway space (Figueroa et al., 1999; Swennen et al., 2000; Appendix A. Supplementary data
Fearon, 2001, 2005; Bannink et al., 2010).
In our cohort, we have been able to reproduce these results both Supplementary data related to this article can be found at
clinically and on three-dimensional analysis of posterior airway https://doi.org/10.1016/j.jcms.2018.11.028.
space. Due to the retrospective analysis of this study, we used all
data that had been available from the patient records. However, References
following these very clear results and results from the literature, it
is debatable whether 3D imaging should be performed on a routine Al-Namnam NMN, Hariri F, Rahman ZAA: Distraction osteogenesis in the surgical
management of syndromic craniosynostosis: a comprehensive review of pub-
basis in these patients or if imaging should be restricted to con-
lished papers. Br J Oral Maxillofac Surg 56: 353e366, 2018
ventional lateral radiographs. While for a long time, conventional Alves PV, Zhao L, O'Gara M, Patel PK, Bolognese AM: Three-dimensional cephalo-
lateral radiographs have been used to plan and follow-up LFIII DO, metric study of upper airway space in skeletal class II and III healthy patients.
this modality does not allow for three-dimensional analysis. With J Craniofac Surg 19: 1497e1507, 2008
Arnaud E, Di Rocco F: Faciocraniosynostosis: monobloc frontofacial osteotomy
regard to the enormous advances in digital three-dimensional replacing the two-stage strategy? Childs Nerv Syst 28: 1557e1564, 2012
analysis, visualization and treatment planning with the possibility Arnaud E, Marchac D, Renier D: Reduction of morbidity of the frontofacial mono-
of individual planning of osteotomy lines and patient-specific im- bloc advancement in children by the use of internal distraction. Plast Reconstr
Surg 120: 1009e1026, 2007
plants and the nature of these rare, complex syndromic cases, we Bannink N, Nout E, Wolvius EB, Hoeve HL, Joosten KF, Mathijssen IM: Obstructive
favor three-dimensional CBCT preoperatively and at the end of the sleep apnea in children with syndromic craniosynostosis: long-term respiratory
distraction period as our gold standard. However, we discuss outcome of midface advancement. Int J Oral Maxillofac Surg 39: 115e121, 2010
Boston M, Rutter MJ: Current airway management in craniofacial anomalies. Curr
increased radiation dose critically with the parents. Opin Otolaryngol Head Neck Surg 11: 428e432, 2003
Aside from functional aspects, LFIII also helps to improve facial Bouw FP, Nout E, van Bezooijen JS, Koudstaal MJ, Veenland JF, Wolvius EB: Three-
morphological features and promotes better psychosocial adapta- dimensional position changes of the midface following Le Fort III advancement
in syndromic craniosynostosis. J Cranio-Maxillo-Facial 43: 820e824, 2015
tion during early development. A very important part in the Bradley JP, Gabbay JS, Taub PJ, Heller JB, O'Hara CM, Benhaim P, Kawamoto Jr HK:
improvement of facial morphological features is the correction of Monobloc advancement by distraction osteogenesis decreases morbidity and
patients' exorbitism and the class III occlusion. We reached this goal relapse. Plast Reconstr Surg 118: 1585e1597, 2006
Britto JA, Evans RD, Hayward RD, Jones BM: Maxillary distraction osteogenesis in
and patients’ exorbitism and angle class III malocclusions were
Pfeiffer's syndrome: urgent ocular protection by gradual midfacial skeletal
corrected in all of our cases. All patients showed a significant advancement. British journal of plastic surgery 51: 343e349, 1998
improvement of the facial morphological features with good to very Burstein F, Soldanska M, Granger M, Berhane C, Schoemann M: Initial experience
good esthetic and surgical outcomes according to the Whitaker with a new intraoral midface distraction device. J Craniofac Surg 26:
1224e1228, 2015
classification and as judged by the parents and the surgical team, Cedars MG, Linck 2nd DL, Chin M, Toth BA: Advancement of the midface using
regardless of patient age at operation. The good to very good esthetic distraction techniques. Plast Reconstr Surg 103: 429e441, 1999
results with change of syndromic to non-syndromic appearance are Cohen SR, Burstein FD, Stewart MB, Rathburn MA: Maxillary-midface distraction in
children with cleft lip and palate: a preliminary report. Plast Reconstr Surg 99:
an important argument for early LFIII DO at the age of 8e12 to 1421e1428, 1997
minimize psychosocial sequelae of stigma before puberty and Cohen SR, Rutrick RE, Burstein FD: Distraction osteogenesis of the human cranio-
significantly improve quality of life for Crouzon patients. facial skeleton: initial experience with new distraction system. J Craniofac Surg
6: 368e374, 1995
Fearon JA: The Le Fort III osteotomy: to distract or not to distract? Plast Reconstr
5. Conclusion Surg 107: 1091e1103, 2001 discussion 1104-1096
Fearon JA: Halo distraction of the Le Fort III in syndromic craniosynostosis: a long-
term assessment. Plast Reconstr Surg 115: 1524e1536, 2005
LFIII DO is a powerful and reliable surgical procedure in Crouzon
Figueroa AA, Polley JW, Figueroa AD: Biomechanical considerations for distraction
patients and superior to standard LFIII osteotomy in the growing of the monobloc, Le Fort III, and Le Fort I segments. Plast Reconstr Surg 126:
child in many aspects, and has the ability to produce more signif- 1005e1013, 2010
Figueroa AA, Polley JW, Ko EW: Maxillary distraction for the management of cleft
icant change of appearance than most other single procedures
maxillary hypoplasia with a rigid external distraction system. Semin Orthod 5:
routinely performed by craniofacial surgeons. 46e51, 1999
This procedure is indicated for children with Crouzon syndrome Gillies H, Harrison SH: Operative correction by osteotomy of recessed malar
and hypoplastic midface. In our collective, the maxilla remained maxillary compound in a case of oxycephaly. Br J Plast Surg 3: 123e127, 1950
Hoeve LJ, Pijpers M, Joosten KF: OSAS in craniofacial syndromes: an unsolved
stable after advancement without any relapse, but there was no problem. Int J Pediatric Otorhinolaryngol 67(Suppl. 1): S111eS113, 2003
subsequent anterior growth up to one year postoperatively. The Hollway GE, Suthers GK, Haan EA, Thompson E, David DJ, Gecz J, Mulley JC: Mu-
technique effectively improved sleep apnea in all affected patients, tation detection in FGFR2 craniosynostosis syndromes. Human Genet 99:
251e255, 1997
and was not associated with any long-term effects on speech or Hopper RA, Sandercoe G, Woo A, Watts R, Kelley P, Ettinger RE, Saltzman B:
mastication. Complication rates in our series were found to be Computed tomographic analysis of temporal maxillary stability and pter-
acceptably low and patients’ functional and esthetic outcome was ygomaxillary generate formation following pediatric Le Fort III distraction
advancement. Plast Reconstr Surg 126: 1665e1674, 2010
high. Although a frontal overbite could be achieved in eight pa- Hu CH, Wu CT, Ko EW, Chen PK: Monobloc frontofacial or Le Fort III distraction
tients at the end of the distraction and observation period, long osteogenesis in syndromic craniosynostosis: three-dimensional evaluation of
term follow-up examinations of our patients will be necessary to treatment outcome and the need for central distraction. J Craniofac Surg 28:
1344e1349, 2017
evaluate whether LFIII distraction can avoid a second LFIII pro- Iannetti G, Ramieri V, Pagnoni M, Fadda MT, Cascone P: Le Fort III external midface
cedure that is routinely required with the conventional LFIII pro- distraction: surgical outcomes and skeletal stability. J Craniofac Surg 23:
cedure and the rate of orthognathic surgery in these patients. While 896e900, 2012
Kapucu MR, Gursu KG, Enacar A, Aras S: The effect of cleft lip repair on maxillary
there is agreement on the surgical technique, distraction rates and
morphology in patients with unilateral complete cleft lip and palate. Plast
retention period, the potential of further growth reflected by the Reconstr Surg 97: 1371e1375, 1996 discussion 1376-1378
amount of overcorrection and the use of internal versus external Kim YJ, Hong JS, Hwang YI, Park YH: Three-dimensional analysis of pharyngeal airway
devices are still under debate. in preadolescent children with different anteroposterior skeletal patterns. Am J
Orthod Dentofac Orthop 137, 2010 306. e301-311; discussion 306-307
In our cohort, the use of external distraction devices was asso- Kuroda S, Watanabe K, Ishimoto K, Nakanishi H, Moriyama K, Tanaka E: Long-term
ciated with a relatively high level of minor distractor related stability of LeFort III distraction osteogenesis with a rigid external distraction
430 M. Engel et al. / Journal of Cranio-Maxillo-Facial Surgery 47 (2019) 420e430

device in a patient with Crouzon syndrome. Am J Orthod Dentofac 140: Roldan JC, Moralis A, Dendorfer S, Witte J, Reicheneder C: Controlled central
550e561, 2011 advancement of the midface after Le Fort III osteotomy by a 3-point skeletal
Lee DW, Ham KW, Kwon SM, Lew DH, Cho EJ: Dual midfacial distraction osteo- anchorage. J Craniofac Surg 22: 2384e2386, 2011
genesis for Crouzon syndrome: long-term follow-up study for relapse and Saltaji H, Altalibi M, Major MP, Al-Nuaimi MH, Tabbaa S, Major PW, Flores-Mir C: Le
growth. J Oral Maxillofac 70: e242ee251, 2012 Fort III distraction osteogenesis versus conventional Le Fort III osteotomy in
Mahadevan M, Barber C, Salkeld L, Douglas G, Mills N: Pediatric tracheotomy: 17 correction of syndromic midfacial hypoplasia: a systematic review. J Oral
year review. Int J Pediatr Otorhinolaryngol 71: 1829e1835, 2007 Maxillofac Surg 72: 959e972, 2014
McCarthy JG, Grayson B, Bookstein F, Vickery C, Zide B: Le Fort III advancement Satoh K, Mitsukawa N, Tosa Y, Kadomatsu K: Le Fort III midfacial distraction using
osteotomy in the growing child. Plast Reconstr Surg 74: 343e354, 1984 an internal distraction device for syndromic craniosynostosis: device selection,
Meazzini MC, Allevia F, Mazzoleni F, Ferrari L, Pagnoni M, Iannetti G, Bozzetti A, problems, indications, and a proposal for use of a parallel bar for device-setting.
Brusati R: Long-term follow-up of syndromic craniosynostosis after Le Fort III J Craniofac Surg 17: 1050e1058, 2006
halo distraction: a cephalometric and CT evaluation. J Plast Reconstruct Aesthet Shetye PR, Davidson EH, Sorkin M, Grayson BH, McCarthy JG: Evaluation of three
Surg 65: 464e472, 2012 surgical techniques for advancement of the midface in growing children with
Meazzini MC, Mazzoleni F, Caronni E, Bozzetti A: Le Fort III advancement osteotomy syndromic craniosynostosis. Plast Reconstr Surg 126: 982e994, 2010
in the growing child affected by Crouzon's and Apert's syndromes: presurgical Shetye PR, Giannoutsos E, Grayson BH, McCarthy JG: Le Fort III distraction: Part I.
and postsurgical growth. J Craniofac Surg 16: 369e377, 2005 Controlling position and vectors of the midface segment. Plast Reconstr Surg
Meling TR, Hogevold HE, Due-Tonnessen BJ, Skjelbred P: Midface distraction 124: 871e878, 2009
osteogenesis: internal vs. external devices. Int J Oral Maxillofac Surg 40: Sinha R, Menon PS, Venugopal MG: A clinical evaluation of midface advancement
139e145, 2011 using intraoral distractors in management of bone stock deficiencies. Med J
Moore MH: Upper airway obstruction in the syndromal craniosynostoses. Br J Plast Armed Forces India 67: 245e252, 2011
Surg 46: 355e362, 1993 Stellzig-Eisenhauer A, Meyer-Marcotty P: Interaction between otorhinolaryngology
Nakajima H, Sakamoto Y, Tamada I, Ohara H, Kishi K: An internal distraction device and orthodontics: correlation between the nasopharyngeal airway and the
for Le Fort distraction osteogenesis: the NAVID system. J Plast Reconstruct craniofacial complex. GMS Curr Top Otorhinolaryngol Head Neck Surg 9, 2010
Aesthet Surg 65: 61e67, 2012 Doc04
Nout E, Cesteleyn LL, van der Wal KG, van Adrichem LN, Mathijssen IM, Wolvius EB: Swennen G, Dujardin T, Goris A, De Mey A, Malevez C: Maxillary distraction osteo-
Advancement of the midface, from conventional Le Fort III osteotomy to Le Fort III genesis: a method with skeletal anchorage. J Craniofac Surg 11: 120e127, 2000
distraction: review of the literature. Int J Oral Maxillofac Surg 37: 781e789, 2008 Swennen G, Schliephake H, Dempf R, Schierle H, Malevez C: Craniofacial distraction
Park JW, Kim NK, Kim JW, Kim MJ, Chang YI: Volumetric, planar, and linear analyses osteogenesis: a review of the literature: Part 1: clinical studies. Int J Oral
of pharyngeal airway change on computed tomography and cephalometry after Maxillofac Surg 30: 89e103, 2001
mandibular setback surgery. Am J Orthod Dentofac Orthop 138: 292e299, 2010 Tessier P: Total facial osteotomy. Crouzon's syndrome, Apert's syndrome: oxy-
Patel PA, Shetye P, Warren SM, Grayson BH, McCarthy JG: Five-year follow-up of cephaly, scaphocephaly, turricephaly. Ann Chir Plast 12: 273e286, 1967
midface distraction in growing children with syndromic craniosynostosis. Plast Tessier P: The definitive plastic surgical treatment of the severe facial deformities of
Reconstr Surg 140: 794ee803e, 2017 craniofacial dysostosis. Crouzon's and Apert's diseases. Plast Reconstr Surg 48:
Pijpers M, Poels PJ, Vaandrager JM, de Hoog M, van den Berg S, Hoeve HJ, 419e442, 1971
Joosten KF: Undiagnosed obstructive sleep apnea syndrome in children with Toth BA, Kim JW, Chin M, Cedars M: Distraction osteogenesis and its application to
syndromal craniofacial synostosis. J Craniofac Surg 15: 670e674, 2004 the midface and bony orbit in craniosynostosis syndromes. J Craniofac Surg 9:
Polley JW, Figueroa AA, Charbel FT, Berkowitz R, Reisberg D, Cohen M: Mon- 100e113, 1998 discussion 119-122
obloc craniomaxillofacial distraction osteogenesis in a newborn with severe Warren SM, Shetye PR, Obaid SI, Grayson BH, McCarthy JG: Long-term evaluation of
craniofacial synostosis: a preliminary report. J Craniofac Surg 6: 421e423, midface position after Le Fort III advancement: a 20-plus-year follow-up. Plast
1995 Reconstr Surg 129: 234e242, 2012
Ponniah AJ, Witherow H, Richards R, Evans R, Hayward R, Dunaway D: Three- Wery MF, Nada RM, van der Meulen JJ, Wolvius EB, Ongkosuwito EM: Three-
dimensional image analysis of facial skeletal changes after monobloc and dimensional computed tomographic evaluation of Le Fort III distraction
bipartition distraction. Plast Reconstr Surg 122: 225e231, 2008 osteogenesis with an external device in syndromic craniosynostosis. Br J Oral
Ridgway EB, Robson CD, Padwa BL, Goumnerova LC, Mulliken JB: Meningoence- Maxillofac Surg 53: 285e291, 2015
phalocele and other dural disruptions: complications of Le Fort III midfacial Whitaker LA, Bartlett SP, Schut L, Bruce D: Craniosynostosis: an analysis of the
osteotomies and distraction. J Craniofac Surg 22: 182e186, 2011 timing, treatment, and complications in 164 consecutive patients. J Plast
Riediger D, Poukens JM: Le Fort III osteotomy: a new internal positioned distractor. Reconstr Surg 80: 195e212, 1987
J Oral Maxillofac Surg 61: 882e889, 2003 Witherow H, Dunaway D, Evans R, Nischal KK, Shipster C, Pereira V, Hearst D,
Ristow O, Ruckschloss T, Berger M, Grotz T, Kargus S, Krisam J, Seeberger R, White M, Jones BM, Hayward R: Functional outcomes in monobloc advance-
Engel M, Hoffmann J, Freudlsperger C: Short- and long-term changes of the ment by distraction using the rigid external distractor device. Plastic Reconstr
pharyngeal airway after surgical mandibular advancement in Class II patients- Surg 121: 1311e1322, 2008
a three-dimensional retrospective study. J Cranio-Maxillo-Facial Surg 46: Xu H, Yu Z, Mu X: The assessment of midface distraction osteogenesis in treatment
56e62, 2018 of upper airway obstruction. J Craniofac Surg 20(Suppl. 2): 1876e1881, 2009