Monobloc Frontofacial or Le Fort III Distraction Osteogenesis in Syndromic Craniosynostosis: Three-Dimensional Evaluation of Treatment Outcome and the Need for Central Distraction

Effects of distraction osteogenesis with Le Fort osteotomies on upper airway volumes: a systematic review and meta-analyses

OBJECTIVE

Distraction osteogenesis is one of the treatment options in patients with severe maxillomandibular abnormalities to treat morphological and respiratory problems (obstructive sleep apnea syndrome). The study aimed to evaluate the effect of Le Fort I, II and III distraction osteogenesis (DO) on upper airway dimensions and respiratory function.

METHODS

Electronic search was performed in PubMed, Scopus, Embase, Google Scholar and Cochrane databases. Studies that only involved two dimensional analyses were excluded. Besides, studies that performed DO in conjunction with orthognathic surgery were not considered. NIH quality assessment tool was used to evaluate the risk of bias. Meta-analyses were performed to assess sleep apnea indices and the mean differences in the airway dimensions before and after DO. Gradings of Recommendations, Assessment, Development and Evaluation were used to analyze the evidence level.

RESULTS

Among the 114 studies that went under full-text analyses, 11 articles met the inclusion criteria. Results of the quantitative analyses showed that maxillary Le Fort III DO significantly increased the amounts of oropharyngeal, pharyngeal and upper airway volumes. However, apnea-hypopnea index (AHI) showed a non-significant improvement after this procedure. Besides, the dimensions of the airways increased with Le Fort I and II DO, according to a qualitative analysis. Considering the design of the included studies, our results had a low level of evidence.

CONCLUSION

Maxillary Le Fort DO does not significantly impact AHI, while it significantly increases the airway dimensions. Meanwhile, multicentric studies with standardized evaluation are still required to confirm the effects of maxillary Le Fort DO on airway obstruction.

Apert Syndrome: Selection Rationale for Midface Advancement Technique

Apert syndrome is characterized by a wide spectrum of craniofacial clinical features that have been successfully addressed via a variety of midface advancement techniques. Although surgeons have individual preferences as to which specific procedures should be performed to best treat Apert patients, craniofacial plastic surgeons, working in tandem with pediatric neurosurgeons, can identify and evaluate functional limitations and facial morphologic disproportions, and establish appropriate criteria for effective midface advancement technique indication and selection. The purpose of this review article is to present and discuss our rationale for midface advancement technique selection based upon the most common craniofacial characteristics presented by Apert syndrome patients. The present article also provides a grading system that stratifies as major, moderate, and mild, the effect of each midface advancement technique on the different types of Apert syndrome facial features. Surgeons should take into consideration the maximum effect and benefit of each craniofacial osteotomy and how these procedures will alter the craniofacial skeleton. By understanding the long-term effect of each osteotomy on the most common craniofacial characteristics of Apert syndrome patients, craniofacial plastic surgeons and neurosurgeons will be able to customize the surgical procedures they perform in order to achieve the best possible outcomes.

Monobloc Differential Distraction Osteogenesis

ABSTRACT

Midface advancement at the monobloc level can be the seminal life event for patients with craniofacial dysostosis. Monobloc reconstruction, when planned appropriately, can simultaneously and definitively address multiple functional and aesthetic deficiencies in these patients. The application of distraction has reduced the morbidity experienced with traditional monobloc surgery. The purpose of this study is to report on the outcomes, stability, and growth in younger patients after monobloc advancement in syndromic craniosynostosis patients. The authors report a consecutive series of thirty patients with craniofacial dysostosis treated through monobloc differential distraction osteogenesis. Detailed history, photographic, and long-term radiographic data are reviewed, including a subset of patients who were skeletally immature at the time of their treatment. Differential distraction allows control of midface pitch, roll, and yaw, optimizing functional and aesthetic outcomes. There were no infectious complications requiring reoperation. The average surgical age for all patients was 12.5 years. For the 7 patients age <7 years, average age was 6 years. For all patients, the mean horizontal movement was 12 mm at nasion and 10 mm at A-point. At mean follow-up (4.8 years entire group and 6.2 years age <7 years group) a positive horizontal advancement of 1.1 mm at nasion and 0.8 mm at A-point was observed. More pronounced positive horizontal changes were seen in the age <7 years group. Monobloc differential distraction osteogenesis affords safe and precise repositioning of the midface. The advancement is skeletally stable and young patients show moderate continued growth.

Lefort II distraction with zygomatic repositioning versus Lefort III distraction: A comparison of surgical outcomes and complications

The aim of the study was to determine if the additional surgical complexity of Lefort II distraction with zygomatic repositioning (LF2ZR) results in increased complications compared to Lefort III distraction (LF3). A retrospective review was performed of all LF3 and LF2ZR advancements performed by the senior author over 15 years. Demographic, operative, postoperative, and cephalometric data were collected from initial procedure through greater than 1 year postoperatively. Univariate and multivariate analyses were performed to compare procedures. 19 LF2ZR and 39 LF3 in 53 patients met inclusion criteria. Diagnoses differed between procedures, with more Crouzon Syndrome in LF3 and more Apert Syndrome in LF2ZR. Complication rate was 7/19 for LF2ZR and 12/39 for LF3 with no severe morbidity or mortality, and no difference between procedures (p = 0.56). The types of complications encountered differed between procedures. LF2ZR had a significantly longer operative time (506 ± 18 vs. 358 ± 24 min, p<0.001). However, a greater number of LF2ZR patients underwent concomitant procedures (15/19 vs. 13/39, p<0.001). Multivariate analysis revealed that Apert Syndrome and reoperative midface advancement were the most significant predictors of increased blood loss. LF2ZR has an equivalent complication rate to LF3. Therefore, it is our treatment of choice for cases requiring differential sagittal and vertical distraction of the central midface.

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.

Analysis of Airway and Midface in Crouzon Syndromes

BACKGROUND

Crouzon syndrome is associated with severe respiratory impairment of the upper airway due in part to midfacial dysmorphology. We calculated the distinctive nasal diameter and pharyngeal airway volume in patients with Crouzon syndrome and compared them with age-matched control subjects.

METHODS

Children with computed tomography scans in the absence of surgical intervention were included. Computed tomography scans were digitized and manipulated using Surgicase CMF (Materialise). Craniometric data relating to the midface and airway were collected. For all linear measurements, mean percent increases or decreases were calculated relative to the size of control subjects, and volumetric assessment of the airway was tabulated. Statistical analysis was performed using t test.

RESULTS

Twenty-six computed tomography scans were included (control n = 17, Crouzon n = 9). All children were in early mixed dentition. Pharyngeal airway volume was decreased in patients with Crouzon syndrome relative to control subjects by 46% (P = 0.003). The distance from the posterior tongue to the posterior pharyngeal wall decreased 31% when comparing the Crouzon group versus the control (P = 0.04).

CONCLUSIONS

Three-dimensional analysis revealed notably decreased pharyngeal and nasal airway volumes in patients with Crouzon syndrome, but nasal bone tissue and soft tissue measurements showed very little change between patients and control subjects.