New trends in cranio-orbital and midface distraction for craniofacial dysostosis

Influence of Nonsyndromic Bicoronal Synostosis and Syndromic Influences on Orbit and Periorbital Malformation

BACKGROUND

Oculoorbital disproportion in patients with craniosynostosis has similarities and dissimilarities between syndromic and nonsyndromic cases. The authors hypothesized that these two conditions have specific individual influences as they relate to development of the orbital and periorbital skeletons.

METHODS

A total of 133 preoperative computed tomography scans (nonsyndromic bicoronal synostosis, n = 38; Apert syndrome bicoronal synostosis subtype, n = 33; Crouzon syndrome bicoronal synostosis subtype, n = 10; controls, n = 52) were included. Craniometric and volumetric analyses related to the orbit and periorbital anatomy were performed.

RESULTS

Orbital cavity volume was mildly restricted in nonsyndromic bicoronal synostosis (7 percent, p = 0.147), but more so in Apert and Crouzon syndromes [17 percent (p = 0.002) and 21 percent (p = 0.005), respectively]. The sphenoid side angle in Apert syndrome was wider than when compared to Crouzon syndrome (p = 0.043). The ethmoid side angle in Apert patients, however, was narrower (p = 0.066) than that in Crouzon patients. Maxilla anteroposterior length was more restricted in Apert syndrome than Crouzon syndrome (21 percent, p = 0.003) and nonsyndromic cases (26 percent, p < 0.001). The posterior nasal spine position was retruded in Crouzon syndrome (39 percent, p < 0.001), yet the anterior nasal spine position was similar in Apert and Crouzon syndromes.

CONCLUSIONS

Orbit and periorbital malformation in syndromic craniosynostosis is likely the combined influence of syndromic influences and premature suture fusion. Apert syndrome expanded the anteriorly contoured lateral orbital wall associated with bicoronal synostosis, whereas Crouzon syndrome had more infraorbital rim retrusion, resulting in more severe exorbitism. Apert syndrome developed maxillary hypoplasia, in addition to the maxillary retrusion, observed in Crouzon syndrome and nonsyndromic bicoronal synostosis patients.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, II.

Orbital and Periorbital Dysmorphology in Untreated Pfeiffer Syndrome

BACKGROUND

Visual impairment secondary to orbital and periorbital dysmorphology is frequent in Pfeiffer syndrome patients. The etiopathogenesis of this aberrancy, however, remains unclear.

METHODS

Untreated Pfeiffer syndrome patients (n = 31) and normal control subjects (n = 43) were compared. Craniometric and volumetric analyses related to the orbital and periorbital anatomy were performed using Materialise (Leuven, Belgium) software.

RESULTS

Overall, orbital cavity volume of Pfeiffer patients is reduced by 28 percent (p < 0.001), compared to normal, starting before 3 months of age (p = 0.004). Globe volume was diminished by 10 percent (p = 0.041) before 3 months of age, yet tended to catch up thereafter. However, the retrobulbar soft-tissue volume remained smaller beyond 1 year of age (17 percent, p = 0.003). Globe volume projection beyond the bony orbit increased in all observed ages (82 percent, p < 0.001). The volumes of sphenoid bone, maxilla, and mandible proportionately were restricted by 24 to 25 percent (p = 0.003 to 0.035) before 3 months of age. The volume of maxilla and mandible gradually approximate normal; however, the sphenoid bone volume in Pfeiffer patients remains less than normal (p = 0.002) into childhood. The anteroposterior length of both the zygoma and the maxilla was reduced by 14 percent (p < 0.001). Anterior positioning of the zygoma is less by 23 percent (p < 0.001) in Pfeiffer patients overall, with anterior positioning of maxilla reduced similarly by 23 percent (p < 0.001).

CONCLUSIONS

Pfeiffer syndrome patients develop decreased retrobulbar soft-tissue and globe volume, along with a restricted orbital cavity volume in infancy. Significant hypoplasia of the sphenoid bone is associated with more severe central facial (maxilla) retrusion, compared to lateral facial structures (zygoma).

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, II.

Monobloc Distraction and Facial Bipartition Distraction with External Devices

Monobloc and bipartition advancement by external distraction plays a major role in the treatment of syndromic craniosynostosis. They can reverse the associated facial deformity and play a role in the management of ocular exposure, intracranial hypertension, and upper airway obstruction. Facial bipartition distraction corrects the intrinsic facial deformities of Apert syndrome. Both procedures are associated with relatively high complication rates principally related to ascending infection and persistent cerebrospinal fluid leaks. Modern perioperative management has resulted in a significant decline in complications. External distractors allow fine tuning of distraction vectors and improve outcome but are less well tolerated than internal distractors.

Morphological Basis for Airway Surgical Intervention in Apert Syndrome

OBJECTIVE

Previous studies have explored the restricted nasopharyngeal airway in Apert syndrome patients. This study aims to investigate the segmented airway volume changes with age and directly analyze their correlations with subcranial dimensions and angulations.

METHODS

Ninety-seven preoperative computed tomography scans (Apert, n = 44; control, n = 53) were included in this study, and divided into 5 age-related subgroups. Computed tomography scans were measured using Mimics and 3-matics software.

RESULTS

Before 6 months of age, the nasal cavity in Apert syndrome is reduced by 47% (P = 0.002), which gradually approximates normal thereafter; however, there remained a 30% reduction, compared with controls. It is highly correlated with the anteroposterior length of subcranial space, and the position of maxilla and palate. The pharyngeal airway volume in Apert syndrome patients, younger than 6 months, was larger than normal by 129% (P = 0.013). However, between 2 and 6 years of age, the pharyngeal airway becomes smaller than normal, with a 57% (P = 0.010) reduction in childhood and 52% (P = 0.005) in adolescence. It is closely correlated with the intercondylar and intergonial widths.

CONCLUSIONS

Airway compromise in Apert syndrome patients is attributable more to the nasal cavity in infants, but in the older child, it is the pharyngeal region. The restricted nasal airway in Apert syndrome is correlated with the subcranial space length and width, but independent of cranial base flexion. The pharyngeal airway volume in Apert syndrome is not as highly correlated with craniofacial morphology. Rather, it is impacted by the growth of mandible, which often requires surgical intervention later in childhood.

Cephalocranial Disproportionate Fossa Volume and Normal Skull Base Angle in Pfeiffer Syndrome

BACKGROUND

Pfeiffer syndrome is a rare syndromic craniosynostosis disorder, with a wide range of clinical manifestations. This study aims to investigate the structural abnormalities of cranial fossa and skull base development in Pfeiffer patients, to provide an anatomic basis for surgical interventions.

METHOD

Thirty preoperative CT scans of Pfeiffer syndrome patients were compared to 35 normal controls. Subgroup comparisons, related to differing suture synostosis, were performed.

RESULTS

Overall, the volume of anterior and middle cranial fossae in Pfeiffer patients were increased by 31% (P < 0.001) and 19% (P = 0.004), versus controls. Volume of the posterior fossa in Pfeiffer patients was reduced by 14% (P = 0.026). When only associated with bicoronal synostosis, Pfeiffer syndrome patients developed enlarged anterior (68%, P = 0.001) and middle (40%, P = 0.031) fossae. However, sagittal synostosis cases only developed an enlarged anterior fossa (47%, P < 0.001). The patients with solely bilateral squamosal synostosis, developed simultaneous reduced anterior, middle and posterior cranial fossae volume (all P ≤ 0.002). The overall skull base angulation, measured on both intracranial and subcranial surfaces, grew normally.

CONCLUSION

Enlarged anterior cranial fossae in Pfeiffer syndrome children is evident, except for the squamosal synostosis cases which developed reduced volume in all fossae. Volume of the middle cranial fossa is influenced by associated cranial vault suture synostosis, specifically, sagittal synostosis cases develop normal middle fossa volume, while the bicoronal cases develop increased middle fossa volume. Posterior cranial fossa development is restricted by shortened posterior cranial base length. Surgical intervention in Pfeiffer syndrome patients optimally should be indexed to different suture synostosis.

Nasopharyngeal airway and subcranial space analysis in Pfeiffer syndrome

Tracheotomy in infancy helps patients with Pfeiffer syndrome to survive by preventing respiratory crisis, but difficulty in decannulation may consequently be a challenge. This study has investigated the regional abnormalities of the nasopharyngeal airway in children with Pfeiffer syndrome to provide an anatomical basis for the surgical treatment and decannulation of the upper airway. Seventy-two preoperative computed tomograms (CT) (Pfeiffer syndrome n=30; control n=42) were included. The airway volume, cross-sectional area, and cephalometrics were measured using Materialise software. Patients with Pfeiffer syndrome developed a 50% (p<0.001) reduction of nasal airway volume, and a 44% (p=0.003) restriction in pharyngeal airway volume. In patients with Pfeiffer syndrome the cross-sectional area at the choana was only half that of the controls (p<0.001). The posterior width of the nasal airway in patients with Pfeiffer syndrome was shortened by 13% (p=0.003), and the height reduced by 21% (p<0.001). The cross-sectional areas at the condylion and gonion levels, which indicate the calibre of the pharyngeal airway at the entrance and midsection, were reduced by 67% (p<0.001) and 47% (p<0.001), respectively, when compared with the controls. The volume of the nasal airway in patients with Pfeiffer syndrome was significantly restricted in length, height, and width, and by choanal stenosis in all cases in this cohort. The reduced anteroposterior length of the nasal airway contributed to the shortened maxilla more than the anteroposterior position. The limited height and width of the nasal pathway was the result of a hypoplastic sphenoid. Restricted mediolateral and anteroposterior dimensions were evident across the entire course of the pharyngeal airway. Mediolateral maxillary expansion in addition to maxillomandibular advancement is therefore likely to benefit these patients.

Midface Morphology and Growth in Syndromic Craniosynostosis Patients Following Frontofacial Monobloc Distraction

BACKGROUND

Facial advancement represents the essence of the surgical treatment of syndromic craniosynostosis. Frontofacial monobloc distraction is an effective surgical approach to correct midface retrusion although someone consider it very hazardous procedure. The authors evaluated a group of patients who underwent frontofacial monobloc distraction with the aim to identify the advancement results performed in immature skeletal regarding the midface morphologic characteristics and its effects on growth.

METHODS

Sixteen patients who underwent frontofacial monobloc distraction with pre- and postsurgical computed tomography (CT) scans were evaluated and compared to a control group of 9 nonsyndromic children with CT scans at 1-year intervals during craniofacial growth. Three-dimensional measurements and superimposition of the CT scans were used to evaluate midface morphologic features and longitudinal changes during the craniofacial growth and following the advancement. Presurgical growth was evaluated in 4 patients and postsurgical growth was evaluated in 9 patients.

RESULTS

Syndromic maxillary width and length were reduced and the most obtuse facial angles showed a lack in forward projection of the central portion in these patients. Three-dimensional distances and images superimposition demonstrated the age did not influence the course of abnormal midface growth.

CONCLUSION

The syndromic midface is hypoplastic and the sagittal deficiency is associated to axial facial concavity. The advancement performed in mixed dentition stages allowed the normalization of facial position comparable to nonsyndromic group. However, the procedure was not able to change the abnormal midface architecture and craniofacial growth.

Long Term Speech Outcomes Following Midface Advancement in Syndromic Craniosynostosis

Midface advancement by distraction osteogenesis (DO) is commonly performed in patients with craniosynostosis for indications including midface hypoplasia, exorbitism, obstructive sleep apnea, class III malocclusion, and overall aesthetic facial deficiency. There is evidence to suggest that maxillary LeFort I advancement increases the risk of velopharyngeal dysfunction in the cleft palate population, yet few studies have investigated changes in speech following LeFort III or monobloc midface advancement in patients with syndromic craniosynostosis. The purpose of this study was to examine the effect of midface DO on speech as indicated by the Pittsburgh Weighted Speech Score in patients with Apert, Crouzon, and Pfeiffer Syndrome. Among 73 midface advancement cases performed during the study period, 19 cases met inclusion criteria. Overall, the highest post-advancement Pittsburgh Weighted Speech Score (PWSS) was significantly higher than the pre-advancement PWSS (0.52 versus 2.42, P = 0.01), indicating an acute worsening of VPI post-advancement. Specifically, the PWSS components nasal emission and nasality were significantly higher post-advancement than pre-advancement (nasal emission: 1.16 versus 0.21, P = 0.02) (nasality: 0.68 versus 0.05, P = 0.04). However, there was no significant difference between pre-advancement PWSS and the latest post-advancement PWSS (P = 0.31). Midface distraction is associated with an acute worsening of VPI post-operatively that is followed by improvement, and often resolution over time. Future work with additional patient accrual is needed to determine the effect of different advancement procedures and syndromes on VPI rates and profundity.

Surgical-Orthodontic Considerations in Subcranial and Frontofacial Distraction

Subcranial and frontofacial distraction osteogenesis have emerged as powerful tools for management of hypoplasia involving the upper two-thirds of the face. The primary goal of subcranial or frontofacial distraction is to improve the orientation of the upper face and midface structures (frontal bone, orbitozygomatic complex, maxilla, nasal complex) relative to the cranial base, globes, and mandible. The various techniques used are tailored for management of specific phenotypic differences in facial position and may include segmental osteotomies, differential vectors, or synchronous maxillomandibular rotation.

Syndromic Craniosynostosis

Management strategies for syndromic craniosynostosis patients require multidisciplinary subspecialty teams to provide optimal care for complex reconstructive approaches. The most common craniosynostosis syndromes include Apert (FGFR2), Crouzon (FGFR2), Muenke (FGFR3), Pfeiffer (FGFR1 and FGFR2), and Saethre-Chotzen (TWIST). Bicoronal craniosynostosis (turribrachycephaly) is most commonly associated with syndromic craniosynostosis. Disease presentation varies from mild sutural involvement to severe pansynostoses, with a spectrum of extracraniofacial dysmorphic manifestations. Understanding the multifaceted syndromic presentations while appreciating the panoply of variable presentations is central to delivering necessary individualized care. Cranial vault remodeling aims to relieve restriction of cranial development and elevated intracranial pressure and restore normal morphology.

Craniofacial syndromes and sleep-related breathing disorders

Children with craniofacial syndromes are at risk of sleep disordered breathing, the most common being obstructive sleep apnea. Midface hypoplasia in children with craniosynostosis and glossoptosis in children with Pierre Robin syndrome are well recognized risk factors, but the etiology is often multifactorial and many children have multilevel airway obstruction. We examine the published evidence and explore the current management strategies in these complex patients. Some treatment modalities are similar to those used in otherwise healthy children such as adenotonsillectomy, positive pressure ventilation and in the refractory cases, tracheostomy. However, there are some distinct approaches such as nasopharyngeal airways, tongue lip adhesion, mandibular distraction osteogenesis in children with Pierre Robin sequence, and midface advancement in children with craniosynostoses. Clinicians should have a low threshold for referral for evaluation of sleep-disordered-breathing in these patients.

The usage of the three-dimension distractor in the NAVID system for plagiocephaly-three case reports

BACKGROUND

Distraction osteogenesis is a standard method for craniosynostosis. However, the technique using conventional devices still has some disadvantages, especially for anterior or posterior plagiocephaly with complex deformities. In the Nakajima's angle-variable internal distraction (NAVID) system originally for maxillary surgeries, the cranial three-dimension (D) distractor with three dimensionally movable joint at the anterior arm has been developed recently in order to prevent the interference in the distraction process and excessive force.

CASE REPORTS

In this paper, we first reported two cases of anterior plagiocephaly, and one case of posterior plagiocephaly received distraction osteogenesis using new 3-D distractor in the NAVID system. In two cases of anterior plagiocephaly, the reshaping of supra-orbital bar in reference of simulating by the 3-D skull model was performed. In all cases, we fixed two paralleled 2-D distractors and a 3-D distractor in the upper frontal or parietal region.

CONCLUSION

Within the limitations of this study, we believe that the NAVID system is suitable for infant plagiocephaly due to the simple and small joint arm. Furthermore, the usage of the 3-D distractor would reduce the interference with 2-D distractors and easily lead to attainment of targeted distracting distance.

Expansion and compression distraction osteogenesis based on volumetric and neurodevelopmental analysis in sagittal craniosynostosis

PURPOSE

Distraction osteogenesis (DO) is a less daunting procedure than extensive cranial vault remodeling and has been used to correct sagittal craniosynostosis. The purposes of this study are to describe DO in combination with expansion and compression procedures and to report analytic results based on the cranial index (CI), volumetric measurement, and neurodevelopmental tests.

METHODS

Between June 2002 and May 2013, 32 patients with non-syndromic sagittal synostosis who had undergone antero-posterior compression with bitemporal expansion were recruited. Circumferential baseline, mid-sagittal, and bicoronal craniotomies were performed in addition to four-quadrant bone flap procedures via distraction with dural attachment. CI, intracranial volume (ICV), head circumference (HC), and neurodevelopmental outcomes using the Bayley Scales of Infant Development-II (BSID-II) scoring system were analyzed.

RESULTS

Dolichocephalic CI (68.85 ± 3.61) was altered to mesocephalic CI (78.28 ± 3.74) postoperatively. Preoperative ICV and HC determinations were within the normal range for the majority of participants (normal ICV 87.5%, n = 28; normal HC 75%, n = 24). ICV and HC did not show significant changes with postoperative measurements and were maintained within normal ranges. Regarding neurodevelopment, both the mental and psychomotor developmental indices (MDI, PDI) demonstrated significant improvement (MDI, 88.69 ± 17.38 to 96.23 ± 21.05; PDI, 91.38 ± 16.31 to 100 ± 11.51; p < 0.05).

CONCLUSIONS

Symmetric sagittal synostosis can be treated comprehensively through DO in combination with expansion and compression procedures. ICV and HC measurements were useful for designing surgical and postoperative distraction strategies. Achievement of mesocephalic CI and neurodevelopmental improvement validated morphological and functional effectiveness.

Cranial distraction osteogenesis: a proposal of minimal consolidation period

PURPOSE

Cranial distraction osteogenesis (DO) has many advantages for correcting skull deformities: Thus, DO is extensively used for the treatment of skull deformities. However, diverse, unexpected complications are associated with this procedure. In this study, we present the surgical outcomes and complications of DO. Moreover, we propose a modified protocol for DO to reduce complications.

METHODS

This is a retrospective study on managed patients that underwent DO between March 2008 and May 2013. Their clinical courses were reviewed. Distraction protocols were individually inspected, and the final surgical outcomes, including complications, were evaluated.

RESULTS

During the study period, a total of ten patients (seven boys and three girls) were treated at our institute. The median distraction period was 20.5 days (ranging from 17 to 50 days). The range of total distraction length was 19-22 mm. The median consolidation period was 96 days (ranging from 0 to 343 days). All patients achieved the goals of distraction. At follow-up evaluations, all patients, except one, showed good surgical outcomes in both head shape and neurologic symptoms. There were six patients with wound complications during the treatment period. Among them, the distractors were removed early in three patients. Interestingly, even these three patients, without a sufficient consolidation period, showed good outcomes.

CONCLUSIONS

Although DO has many merits for correcting skull deformities, it frequently causes severe wound complications. To reduce these complications, we propose a modified protocol with a minimal or even no consolidation period.

Significance of distraction osteogenesis of the craniomaxillofacial skeleton - a clinical review after 10 years of experience with the technique

INTRODUCTION

Distraction osteogenesis (DO) has been applied to the field of craniomaxillofacial surgery for more than two decades. Although relevant factors for successful distraction osteogenesis are well known there are ongoing controversies about indications and limitations of the method and there is still a lack of evidence based data. Since 2003 the principle of gradual lengthening has been applied to patients affected by different types of skeletal craniomaxillofacial deficiency within individualized treatment protocols at the Campus Virchow Klinikum - Charité Universitätsmedizin Berlin - by the same surgical team. The records of these patients were reviewed in order to assess the significance of the technique within the spectrum of a craniomaxillofacial department. During 10 years DO has been applied in 80 patients representing less than 1% of all patients that have been treated since 2003. Review of the protocols showed a heterogeneous group with a wide variance of parameters, the age ranging from 2½ to 51 years. Internal distraction devices were used in all cases and individually selected with respect to optimal stability during active distraction and consolidation phase. Although distraction related complications occurred the majority of procedures ended up with the favoured result and skeletal stability. However additional reconstructive surgery was required despite successful distraction in the majority of patients. Although DO has a low significance with respect to overall patient counts the method is a powerful tool within individual therapeutic concepts for the surgical correction of craniofacial anomalies that are characterized by skeletal deficiencies and should be seen as addendum to other surgical options. Predictable and stable results can be expected if the basic principles of the method are regarded.

Normalizing facial ratios in apert syndrome patients with Le Fort II midface distraction and simultaneous zygomatic repositioning

BACKGROUND

Le Fort III distraction advances the Apert midface but leaves the central concavity and vertical compression untreated. The authors propose that Le Fort II distraction and simultaneous zygomatic repositioning as a combined procedure can move the central midface and lateral orbits in independent vectors in order to improve the facial deformity. The purpose of this study was to determine whether this segmental movement results in more normal facial proportions than Le Fort III distraction.

METHODS

Computed tomographic scan analyses were performed before and after distraction in patients undergoing Le Fort III distraction (n = 5) and Le Fort II distraction with simultaneous zygomatic repositioning (n = 4). The calculated axial facial ratios and vertical facial ratios relative to the skull base were compared to those of unoperated Crouzon (n = 5) and normal (n = 6) controls.

RESULTS

With Le Fort III distraction, facial ratios did not change with surgery and remained lower (p < 0.01; paired t test comparison) than normal and Crouzon controls. Although the face was advanced, its shape remained abnormal. With the Le Fort II segmental movement procedure, the central face advanced and lengthened more than the lateral orbit. This differential movement changed the abnormal facial ratios that were present before surgery into ratios that were not significantly different from normal controls (p > 0.05).

CONCLUSION

Compared with Le Fort III distraction, Le Fort II distraction with simultaneous zygomatic repositioning normalizes the position and the shape of the Apert face.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.