Apert syndrome: Surgical outcomes and perspectives

Long-Term Follow-Up of Apert Syndrome Following Mid-Face Advancement: More Than 3 Decades Later

Apert syndrome is characterized by craniosynostosis, a hypoplastic mid-face, skeletal abnormalities, symmetric syndactyly of the hands and feet, and a degree of neurocognitive impairment. Long-term outcomes of patients who have undergone surgical correction of Apert syndrome are limited. The authors present the case of a 73-year-old female with Apert syndrome, with follow-up of more than 3 decades following a fronto-orbital advancement and Le Fort III advancement. Clinical and radiologic images demonstrate a degree of skeletal resorption and relapse that is likely unavoidable. This provides insight into the long-term skeletal stability and esthetic outcomes for patients with Apert syndrome.

Craniofacial morphology in Apert syndrome: a systematic review and meta-analysis

This meta-analysis aims to compare Apert syndrome (AS) patients with non-AS populations (not clinically or genetically diagnosed) on craniofacial cephalometric characteristics (CCC) to combine publicly available scientific information while also improving the validity of primary study findings. A comprehensive search was performed in the following databases: PubMed, Google Scholar, Scopus, Medline, and Web of Science, an article published between 1st January 2000 to October 17th, 2021. PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines were followed to carry out this systematic review. We used the PECO system to classify people with AS based on whether or not they had distinctive CCC compared to the non-AS population. Following are some examples of how PECO has been used: People with AS are labeled P; clinical or genetic diagnosis of AS is labeled E; individuals without AS are labeled C; CCC of AS are labeled O. Using the Newcastle–Ottawa Quality-Assessment-Scale, independent reviewers assessed the articles' methodological quality and extracted data. 13 studies were included in the systematic review. 8 out of 13 studies were score 7–8 in NOS scale, which indicated that most of the studies were medium to high qualities. Six case–control studies were analyzed for meta-analysis. Due to the wide range of variability in CCC, we were only able to include data from at least three previous studies. There was a statistically significant difference in N-S-PP (I²: 76.56%; P = 0.014; CI 1.27 to − 0.28) and Greater wing angle (I²: 79.07%; P = 0.008; CI 3.07–1.17) between AS and control subjects. Cleft palate, anterior open bite, crowding in the upper jaw, and hypodontia occurred more frequently among AS patients. Significant shortening of the mandibular width, height and length is the most reported feature in AS patients. CT scans can help patients with AS decide whether to pursue orthodontic treatment alone or to have their mouth surgically expanded. The role of well-informed orthodontic and maxillofacial practitioners is critical in preventing and rehabilitating oral health issues.

Syndromic Hydrocephalus

Hydrocephalus, the abnormal accumulation and impaired circulation/clearance of cerebrospinal fluid, occurs as a common phenotypic feature of a diverse group of genetic syndromes. In this review, we outline the genetic mutations, pathogenesis, and accompanying symptoms underlying syndromic hydrocephalus in the context of: L1 syndrome, syndromic craniosynostoses, achondroplasia, NF 1/2, Down's syndrome, tuberous sclerosis, Walker-Warburg syndrome, primary ciliary dyskinesia, and osteogenesis imperfecta. Further, we discuss emerging genetic variants associated with syndromic hydrocephalus.

Morbidity Associated With Anterior Versus Posterior Cranial Vault Expansion for Early Treatment of Syndromic Craniosynostosis: A Systematic Review and Meta-Analysis

PURPOSE

The purpose of this systematic review and meta-analysis was to estimate and compare rates of unplanned reoperation and complications after undergoing either fronto-orbital advancement (anterior cranial vault expansion) or posterior cranial vault expansion as an early surgery in the management of syndromic craniosynostosis.

MATERIALS AND METHODS

A literature search was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Relevant articles were identified in 2 electronic databases (PubMed and EMBASE) from the time of electronic publication to November 2020. Quality assessment and risk of bias were appraised using the Grading of Recommendations Assessment, Development and Evaluation system. A meta-analysis was performed comparing rates of reoperation and complications between participants who underwent anterior or posterior cranial vault expansion as an early surgery.

RESULTS

Of 1,373 screened records, 7 met inclusion criteria. Six were included in the meta-analysis. The studies that met inclusion criteria reported on 103 patients treated with anterior techniques and 72 patients treated with a posterior approach. Anterior cranial vault expansion was associated with significantly higher rates of reoperation (Peto odds ratio = 2.83; 95% confidence interval = 1.19, 6.74, P = .02) and complications (Peto odds ratio = 2.61; 95% confidence interval = 1.12, 6.12, P = .03) than posterior cranial vault expansion.

CONCLUSIONS

Both anterior and posterior approaches are suitable options in the treatment of syndromic craniosynostosis depending on patient-specific factors. Anterior cranial vault expansion was associated with higher rates of unplanned reoperation and complications than posterior techniques in this analysis. Because of the paucity of literature which met inclusion criteria, this study was not able to assess critical outcome variables such as distance distracted/volumetric expansion, estimated blood loss, and cost. Larger studies evaluating both techniques under multiple institutions with long-term follow-up are indicated.

Apert syndrome diagnosed by prenatal ultrasound combined with magnetic resonance imaging and whole exome sequencing: A case report

BACKGROUND

Most cases of Apert syndrome (AS) are found after birth. Cases of AS diagnosed by ultrasound combined with magnetic resonance imaging (MRI) and whole exome sequencing (WES) during pregnancy are rare.

CASE SUMMARY

We present the case of a 34-year old female patient (gravida 2, para 1) whose fetus was diagnosed with AS during pregnancy. Fetal ultrasound performed at 30, 2/7 wk of pregnancy showed abnormalities. MRI and three-dimensional ultrasound performed at 31, 1/7 wk of pregnancy showed the possibility of AS. Chromosome examination and core family WES were conducted at 31, 5/7 wk of pregnancy. The results showed that FGFR2 in the fetus had a c.755C>G missense mutation in its nucleotide, and AS was confirmed.

CONCLUSION

This case highlights the importance of imaging examinations. Prenatal ultrasound combined with MRI can identify fetal morphological abnormalities accurately, which can be confirmed by WES.

Apert syndrome: Cranial procedures and brain malformations in a series of patients

Background:

Apert syndrome is one of the most severe craniofacial disorders. This study aims to describe the craniofacial surgeries and central nervous system malformations of a cohort of children with Apert syndrome treated in the past 20 years and to compare these data with previously published data.

Methods:

Retrospective analysis of a series of patients with Apert syndrome treated between 1999 and 2019 in our hospital. Information was analyzed regarding craniofacial procedures, hydrocephalus and presence of shunts, Chiari malformation Type 1, and other brain malformations such as corpus callosum and septum pellucidum anomalies.

Results:

Thirty-seven patients were studied. Ventriculoperitoneal shunt prevalence was 24.3%, and 8.1% of patients required decompressive surgery for Chiari malformation. All of them needed at least one cranial vault remodeling procedure. The median age for this procedure was 8 months. In 69.7% of patients, the first cranial vault intervention was performed in the fronto-orbital region. In 36.4% of patients, a midface advancement had been performed at the time of this review, although this proportion was very dependent on the follow-up period and the age of the patients. The median age for the midface advancement procedure was 5.25 years. Anomalies of the corpus callosum and the septum pellucidum were reported in 43.2% and 59.5% of patients, respectively.

Conclusion:

Apert syndrome is a type of syndromic craniosynostosis, and patients usually require one or more cranial and facial surgeries. In comparison with other syndromic craniosynostosis types, Apert syndrome less frequently requires a VP shunt or treatment for a Chiari malformation.

A Procedure for Designing Custom-Made Implants for Forehead Augmentation in People Suffering from Apert Syndrome

This paper presents a methodological procedure, based on the anatomical reconstruction and constrained deformation, to design custom-made implants for forehead augmentation in people affected by Apert syndrome, experiencing a frontal bone deficiency. According to the anthropometric theory, a cranial landmarks identification procedure was applied to retrieve, from a repository, a healthy skull, used as reference geometry for implant modelling. Then, using constrained deformation and free-form modelling techniques, it was possible to design a patient-specific implant. At last, the implant was realised using a custom mould, specially designed according to the patient's needs to provide an accurate fit of the defect site. The design procedure was tested on a patient suffering from Apert syndrome. Three implants were virtually modelled and 3D-printed for pre-surgical evaluation. Their shapes were 3D compared with a reference one (handcrafted by a surgeon) to test the accuracy. Deviations are negligible, and the customised implant fulfilled the surgeon's requirements.

Glycosylation of DMP1 maintains cranial sutures in mice

Craniosynostosis, a severe craniofacial developmental disease, can only be treated with surgery currently. Recent studies have shown that proteoglycans are involved in the suture development. For the bone matrix protein, dentin matrix protein 1 (DMP1), glycosylation on the N-terminal of it could generate a functional proteoglycan form of DMP1 during osteogenesis. We identified that the proteoglycan form of DMP1 (DMP1-PG) is highly expressed in mineralisation front of suture. But, the potential role of DMP1-PG in suture fusion remain unclear. To investigate the role of DMP1-PG in cranial suture fusion and craniofacial bone development. By using a DMP1 glycosylation site mutation mouse model, DMP1-S89G mice, we compared the suture development in it with control mice. We compared the suture phenotypes, bone formation rate, expression levels of bone formation markers in vivo between DMP1-S89G mice and wild-type mice. Meanwhile, cell culture and organ culture were performed to detect the differences in cell differentiation and suture fusion in vitro. Finally, chondroitin sulphate (CHS), as functional component of DMP1-PG, was employed to test whether it could delay the premature suture fusion and the abnormal differentiation of bone mesenchymal stem cells (BMSCs) of DMP1-PG mice. DMP1-S89G mice had premature closure of suture and shorter skull size. Lack of DMP1-PG accelerated bone formation in cranial suture. DMP1-PG maintained the essential stemness of BMSCs in suture through blocking the premature differentiation of BMSCs to osteoblasts. Finally, chondroitin sulphate, a major component of DMP1-PG, successfully delayed the premature suture fusion by organ culture of skull in vitro. DMP1-PG could inhibit premature fusion of cranial suture and maintain the suture through regulating the osteogenic differentiation of BMSCs.

Infectious Complications After Open Cranial Vault Remodeling for Craniosynostosis

BACKGROUND

Surgical site infection (SSI) after open cranial vault reconstruction (CVR), while relatively uncommon, has received little attention in the literature to date. Here, the authors report our institution's experience with the perioperative management of infectious complications following CVR for craniosynostosis and present the first systematic review of the literature on this topic.

METHODS

The authors performed a retrospective chart review for patients with syndromic and nonsyndromic craniosynostosis who underwent open CVR between 1990 and 2015 at a single institution to determine predictors of SSIs and a systematic review of studies that evaluated for SSI after CVR to ascertain the pooled incidence of SSI, common infectious organisms, and prophylactic antibiotic protocols.

RESULTS

Out of 548 primary and 163 secondary CVR cases at our institution, 6 primary reconstruction patients (1.09%) and 9 secondary reconstruction patients (5.52%) developed an SSI requiring extended hospital stay or readmission (P <0.001); overall infection rate was 2.11%. Streptococcus and Staphylococcus species were the most common organisms isolated. On multivariate analysis, syndromic status conferred more than 7 times greater odds of SSI (OR 7.7, P = 0.023). Pooled analysis of the literature yielded an overall SSI rate of 1.05% to 2.01%. In contrast to our institutional findings, the most common organisms reported were Candida species and Pseudomonas aeruginosa. The most common prophylactic antibiotic protocol was a first-generation cephalosporin for 24 to 72 hours post-operatively.

CONCLUSIONS

Patients undergoing secondary reconstruction have higher infection rates after CVR, and syndromic status is an important predictor of infection when controlling for other patient factors. Our literature review reveals nosocomial organisms to be the most commonly reported source of infection, though this is contrary to our institutional findings of skin flora being most common. Antibiotic prophylaxis varies institutionally.

Retropalatal Cross-Sectional Area Is Predictive of Obstructive Sleep Apnea in Patients With Syndromic Craniosynostosis

OBJECTIVE

There is a high rate of obstructive sleep apnea (OSA) in patients with syndromic craniosynostosis (SCS). Little is known about the airway anatomy in this population. The purpose of this study is to characterize the 3 dimensional (3D) upper airway in patients with SCS with and without OSA.

DESIGN

This is a retrospective study of patients with SCS treated at Boston Children's Hospital from 2000 to 2015. Patients were divided into OSA and no-OSA groups based on polysomnography. Predictor variables included age, sex, body mass index (BMI), and 3D upper airway measurements. The primary outcome variable was the presence or absence of OSA. Secondary outcome variables were apnea-hypopnea index and oxygen saturation nadir. Descriptive and bivariate statistics were computed, and significance was set as P < .05.

RESULTS

There were 24 patients: 16 in the OSA group and 8 in the no-OSA group. The 2 groups did not differ significantly by age, BMI, or syndromic diagnosis. The presence of OSA was associated with a smaller minimum retropalatal cross-sectional area (minRPCSA; P < .001). In a logistic regression model controlling for age, sex, and upper airway length, minRPCSA was the primary predictor of OSA (P ≤ .002). Receiver operating characteristic analysis determined minRPCSA = 55.3 mm² to be the optimal diagnostic threshold for OSA, with sensitivity = 100% and specificity = 87.5% (P < .001).

CONCLUSION

A minRPCSA ≤55.3 mm² is predictive of the presence of OSA in patients with SCS.

Adeno-Associated Virus-Mediated RNAi against Mutant Alleles Attenuates Abnormal Calvarial Phenotypes in an Apert Syndrome Mouse Model

Apert syndrome (AS), the most severe form of craniosynostosis, is caused by missense mutations including Pro253Arg(P253R) of fibroblast growth factor receptor 2 (FGFR2), which leads to enhanced FGF/FGFR2-signaling activity. Surgical correction of the deformed skull is the typical treatment for AS. Because of constant maldevelopment of sutures, the corrective surgery is often executed several times, resulting in increased patient challenge and complications. Biological therapies targeting the signaling of mutant FGFR2 allele, in combination with surgery, may bring better outcome. Here we screened and found a small interfering RNA (siRNA) specifically targeting the Fgfr2-P253R allele, and we revealed that it inhibited osteoblastic differentiation and matrix mineralization by reducing the signaling of ERK1/2 and P38 in cultured primary calvarial cells and calvarial explants from Apert mice (Fgfr2^+/P253R). Furthermore, AAV9 carrying short hairpin RNA (shRNA) (AAV9-Fgfr2-shRNA) against mutant Fgfr2 was delivered to the skulls of AS mice. Results demonstrate that AAV9-Fgfr2-shRNA attenuated the premature closure of coronal suture and the decreased calvarial bone volume of AS mice. Our study provides a novel practical biological approach, which will, in combination with other therapies, including surgeries, help treat patients with AS while providing experimental clues for the biological therapies of other genetic skeletal diseases.