An update of ophthalmic management in craniosynostosis

Ocular manifestations and treatment progress of Crouzon syndrome

PURPOSE

Crouzon syndrome is a congenital genetic disease caused by mutations of the FGFR2 gene on chromosome 10. It is usually inherited in an autosomal dominant pattern and is one of the most common types of craniosynostosis syndromes. This article focuses on the ophthalmology-related aspects of Crouzon syndrome in order to help diagnose and develop personalized treatment plans.

METHODS

A combined systematic search of PubMed electronic database by using Boolean operators AND and OR was conducted, choosing the following keywords: "Crouzon", "craniosynostosis", " eye ", " oculus ", " ocular ", " ophthalmic ", " ophthalmologic ", " ophthalmology ", " globe ", " orbit ", " exophthalmos ", " exorbitism ", " keratopathy ", " visual " etc. After the initial screening of these articles, repetitive literatures were excluded.

RESULTS

47 articles were selected. This article introduces the ocular manifestations, possible pathogenesis and treatment progress in Crouzon syndrome.

CONCLUSIONS

The incidence of ocular abnormalities in Crouzon syndrome is very high, such as shallow orbits, exophthalmos, hypertelorism, exposure keratopathy, strabismus, optic neuropathy, ametropia, glaucoma, etc. The pathogenesis of these ocular abnormalities is related to orbital deformities. Most of the treatments are aimed at compensating the abnormal anatomic structure at present.

Lacrimal Obstruction in Craniosynostosis: Anatomical and Genetic Risk Factors

PURPOSE

To investigate whether patients with craniosynostosis exhibit higher rates of nasolacrimal duct obstruction (NLDO) and to explore potential risk factors.

METHODS

Retrospective review including all craniosynostosis patients treated at both the Divisions of Ophthalmology and Plastic, Reconstructive, and Oral Surgery at The Children's Hospital of Philadelphia between 2009 and 2020 was conducted. Synostosis characteristics, lacrimal disorders, and genetic data were collected. Main outcome measures were the rate of NLDO and associations with anatomical and syndromic/genetic risk factors.

RESULTS

The total of 767 participants had a mean age of 2.8 ± 3.8 years, 465 (60.6%) were males, 485 (63.2%) had no syndromic association; 631 (82.3%) had one major suture involved, 128 (17%) had involvement of 2 to 4 major sutures, and 429 (55.9%) underwent craniofacial surgery. Forty-eight (6.2%) patients had NLDO, which more prevalent in the genetic/syndromic group (11.0% vs. 3.5%, respectively, p < 0.001), with the highest prevalence observed in patients with Apert syndrome (n = 4, 30.8%). The genetic variants most associated with NLDO were EFNB1 (n = 1, 100%) and FGFR2 (n = 6, 19.4%). There was no association between NLDO and the number or types of sutures involved or a history of craniofacial surgery.

CONCLUSIONS

Nasolacrimal duct obstruction is more common in patients with craniosynostosis compared to the general population. Having a putative syndrome or a putative genetic variant and female sex were risk factors for NLDO. Ophthalmic evaluations for all craniosynostosis patients and careful assessments of any symptoms of tearing are recommended.

The Outcome of Inferior Oblique Myectomy for Apparent Inferior Oblique Overaction Associated with Craniosynostosis

PURPOSE

Strabismus in patients with craniosynostosis is common, but surgical correction of strabismus in these patients remains challenging. We report our findings in six patients (four of whom were Korean) with craniosynostosis who underwent strabismus surgery to specifically address V-pattern horizontal strabismus with moderate-to-severe inferior oblique (IO) overaction, using IO myectomy at a single tertiary hospital between 2005 and 2016.

METHODS

We recorded preoperative characteristics including sex, age, type of strabismus, versions grading, refractive error, and visual acuity. The grading of cyclorotation of horizontal rectus muscles by V-pattern categorized using coronal computed tomography imaging.

RESULTS

Of the six patients, exodeviation was found in four patients and vertical deviation in two patients in primary position. One patient had both horizontal and vertical strabismus. Available computed tomography imaging showed that V-patterns were category 1 (mild) in two patients, category 2 (moderate) in one patient, and category 3 (severe) in two patients. Complete success was defined as absence of IO overaction any more. Overall complete success rate of IO myectomy was 83.3%.

CONCLUSIONS

IO myectomy appeared to have some benefits in V-pattern horizontal strabismus with moderate-to-severe IO overaction in patients with craniosynostosis.

Skeletal expansion via craniofacial distraction osteogenesis technique in syndromic craniosynostosis: impact on ophthalmic parameters

BACKGROUND

This study aims to compare the changes in ophthalmic parameters among syndromic craniosynostosis patients who underwent craniofacial skeletal expansion procedures via distraction osteogenesis (DO).

METHOD

A retrospective study was conducted involving syndromic craniosynostosis patients who underwent surgical expansion via the DO technique from the year 2012 to March 2022. Changes in six parameters which consist of visual acuity, refractive error, optic disc health, intraocular pressure, degree of proptosis and orbital volume were measured objectively pre and post-surgery. For categorical parameters, the Chi-square cross-tab test was done. Paired sample T-test was used for normally distributed variables. Wilcoxon signed-rank test was used for non-normally distributed data.

RESULTS

Visual impairment was present in 21.4% of eyes before surgery and increased to 28.5% post-surgery. Three patients had changes of refractive error post-surgery with one developed hypermetropia, another developed anisometropia and the last had improvement to no refractive error. Two patients had optic disc swelling which was resolved post-surgery. Intraocular pressure changes were inconsistent post-surgery. All patients achieved a significant reduction in the degree of proptosis post-surgery. Orbital volume calculation using computed tomography (CT) scans shows a significant increase in volume post-surgery for all patients.

CONCLUSION

Our study shows a significant increase in orbital volume post-surgery with a reduction in the degree of proptosis. Optic disc and nerve health improved after the surgery. Changes in terms of visual acuity, refractive error and IOP were inconsistent after the surgical intervention.

Sensitivity, Specificity, and Cutoff Identifying Optic Atrophy by Macular Ganglion Cell Layer Volume in Syndromic Craniosynostosis

PURPOSE

To determine the sensitivity, specificity, and cutoff of macular ganglion cell layer (GCL) volume consistent with optic atrophy in children with syndromic craniosynostosis and to investigate factors independently associated with reduction in GCL volume.

DESIGN

Retrospective cross-sectional study.

PARTICIPANTS

Patients with syndromic craniosynostosis evaluated at Boston Children's Hospital (2010-2022) with reliable macular OCT scans.

METHODS

The latest ophthalmic examination that included OCT macula scans was identified. Age at examination, sex, ethnicity, best-corrected logarithm of the minimum angle of resolution (logMAR) visual acuity, cycloplegic refraction, and funduscopic optic nerve appearance were recorded in addition to history of primary or recurrent elevation in intracranial pressure (ICP), Chiari malformation, and obstructive sleep apnea (OSA). Spectral-domain OCT software quantified segmentation of macula retinal layers and was checked manually.

MAIN OUTCOME MEASURES

The primary outcome was determining sensitivity, specificity, and optimal cutoff of GCL volume consistent with optic atrophy. The secondary outcome was determining whether previously elevated ICP, OSA, Chiari malformation, craniosynostosis diagnosis, logMAR visual acuity, age, or sex were independently associated with lower GCL volume.

RESULTS

Median age at examination was 11.9 years (interquartile range, 8.5-14.8 years). Fifty-eight of 61 patients (112 eyes) had reliable macula scans, 74% were female, and syndromes represented were Apert (n = 14), Crouzon (n = 17), Muenke (n = 6), Pfeiffer (n = 6), and Saethre-Chotzen (n = 15). Optimal cutoff identifying optic atrophy was a GCL volume < 1.02 mm3 with a sensitivity of 83% and specificity of 77%. Univariate analysis demonstrated that significantly lower macular GCL volume was associated with optic atrophy on fundus examination (P < 0.001), Apert syndrome (P < 0.001), history of elevated ICP (P = 0.015), Chiari malformation (P = 0.001), OSA (P < 0.001), male sex (P = 0.027), and worse logMAR visual acuity (P < 0.001). Multivariable median regression analysis confirmed that only OSA (P = 0.005), optic atrophy on fundus examination (P = 0.003), and worse logMAR visual acuity (P = 0.042) were independently associated with lower GCL volume.

CONCLUSIONS

Surveillance for optic atrophy by GCL volume may be useful in a population where cognitive skills can limit acquisition of other key ophthalmic measures. It is noteworthy that OSA is also associated with lower GLC volume in this population.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Facial skeleton dysmorphology in syndromic craniosynostosis: differences between FGFR2 and no-FGFR2-related syndromes and relationship with skull base and facial sutural patterns

PURPOSE

To assess the role of FGFR2 mutations and sutural synostotic patterns on facial skeleton dysmorphology in children with syndromic craniosynostosis.

METHODS

Preoperative high-resolution CT images in 39 infants with syndromic craniosynostosis were evaluated. Patients were divided into infants with and without FGFR2 mutations; each group was split according to synostotic involvement of minor sutures/synchondroses: isolated or combined involvement of middle (MCF) and posterior cranial fossae (PCF). Quantitative analysis of the midface and mandible measures was performed. Each subgroup was compared with a group of age-matched healthy subjects.

RESULTS

Twenty-four patients with FGFR2 related syndromes were clustered in 3 subgroups: MCF + PCF (8 patients, 5.4 ± 1.75 months), MCF (8 patients, 3.62 ± 1.68 months), and PCF (8 patients, 2.75 ± 0.46 months). Fifteen no-FGFR2 patients were clustered in 2 subgroups: MCF + PCF (7 patients, 9.42 ± 0.78 months) and PCF (8 patients, 7.37 ± 2.92 months). Both FGFR2 and no-FGFR2 groups with involvement of minor sutures coursing in MCF showed more facial sutural synostoses. Children with minor suture/synchondrosis synostosis of MCF (MCF-PCF and MCF subgroups) showed altered position of glenoid fossa and mandibular inclination ([Formula: see text]), but children in the FGFR2 group had also reduced midfacial depth and maxillary length ([Formula: see text]). Children with minor suture/synchondrosis synostosis of PCF (PCF subgroups) had reduced posterior mandibular height, but those children in the FGFR2 group also showed reduced intergonion distance ([Formula: see text]).

CONCLUSIONS

In children with syndromic craniosynostosis, both skull base and facial suture synostosis affect facial dysmorphology/hypoplasia. FGFR2 mutations may worsen facial hypoplasia both acting on bone development and causing an earlier premature closure of facial sutures.

Early Ophthalmology Findings in Nonsyndromic Craniosynostosis

Craniosynostosis (CS) occurs 1 in 2500 births and surgical intervention is indicated partly due to risk for elevated intracranial pressure (EICP). Ophthalmological examinations help identify EICP and additional vision concerns. This study describes preoperative and postoperative ophthalmic findings in CS patients (N=314) from chart review. Patients included nonsyndromic CS: multisuture (6.1%), bicoronal (7.3%), sagittal (41.4%), unicoronal (22.6%), metopic (20.4%), and lambdoidal (2.2%). Preoperative ophthalmology visits were at M =8.9±14.1 months for 36% of patients and surgery was at M =8.3±4.2 months. Postoperative ophthalmology visits were at age M =18.7±12.6 months for 42% with follow-up at M =27.1±15.1 months for 29% of patients. A marker for EICP was found for a patient with isolated sagittal CS. Only a third of patients with unicoronal CS had normal eye exams (30.4%) with hyperopia (38.2%) and anisometropia (16.7%) at higher rates than the general population. Most children with sagittal CS had normal exams (74.2%) with higher than expected hyperopia (10.8%) and exotropia (9.7%). The majority of patients with metopic CS had normal eye exams (84.8%). About half of patients with bicoronal CS had normal eye exams (48.5%) and findings included: exotropia (33.3%), hyperopia (27.3%), astigmatism (6%), and anisometropia (3%). Over half of children with nonsyndromic multisuture CS had normal exams (60.7%) with findings of: hyperopia (7.1%), corneal scarring (7.1%), exotropia (3.6%), anisometropia (3.6%), hypertropia (3.6%), esotropia (3.6%), and keratopathy (3.6%). Given the range of findings, early referral to ophthalmology and ongoing monitoring is recommended as part of CS care.

Lipofilling of the lower eyelids: A craniofacial tool to postpone the facial advancement in craniofacial syndromes

PURPOSE

Many genetic diseases are responsible for a defect in the growth of the maxilla. Craniofacial syndromes such as Crouzon syndrome or Apert syndrome are typically associated with a major hypoplasia in the midface responsible for exophthalmos, leading to palpebral malocclusion and frequent corneal complications. Several treatments have been used to manage ocular protection in craniofacial syndromes such as tarsorrhaphy, a fronto-orbital advancement and/or a Lefort III osteotomy with or without distraction. We describe a new approach as a waiting solution to relieve exophthalmos: the autologous fat grafting of the lower eyelids.

MATERIAL AND METHODS

Children operated from lipofilling of the lower eyelids at the Referral Center for craniosynostosis of Femme-Mère-Enfant Hospital in Lyon, were included. All the patients suffered from midface hypoplasia and exophthalmos with insufficient eyelid closure responsible of multiples episodes of keratitis and corneal ulcerations.

RESULTS

Four children were included: three suffered from Crouzon Syndrome and one suffered from Apert Syndrome. The fat was reinjected at the level of the infraorbital rim, the nasolabial fold or the palpebrojugal fold, in the different planes, according to the patients' needs. Six months after surgery, a second surgery was performed for the patients whose lagophtalmos persisted. Six months after the second procedure, the results are satisfactory with a good eyelid closure.

CONCLUSION

The lipofilling, well used in pediatric surgery to restore facial symmetry, can also be used, as a waiting solution or complement to treat complicated exophtalmos with visual prognosis involved in congenital craniofacial syndromes.

Effect of Fibroblast Growth Factor 2 on Extraocular Muscle Structure and Function

Purpose

Mutations in the fibroblast growth factor (FGF) receptor can result in strabismus, but little is known about how FGFs affect extraocular muscle structure and function. These were assessed after short-term and long-term exposure to exogenously applied FGF2 to determine the effect of enhanced signaling.

Methods

One superior rectus muscle of adult rabbits received either a series of three injections of 500 ng, 1 µg, or 5 µg FGF2 and examined after 1 week, or received sustained treatment with FGF2 and examined after 1, 2, or 3 months. Muscles were assessed for alterations in force generation, myofiber size, and satellite cell number after each treatment.

Results

One week after the 5 µg FGF2 injections, treated muscles showed significantly increased force generation compared with naïve controls, which correlated with increased myofiber cross-sectional areas and Pax7-positive satellite cells. In contrast, 3 months of sustained FGF2 treatment resulted in decreased force generation, which correlated with decreased myofiber size and decreased satellite cells compared with naïve control and the untreated contralateral side.

Conclusions

FGF2 had distinctly different effects when short-term and long-term treatments were compared. The decreased size and ability to generate force correlated with decreased myofiber areas seen in individuals with Apert syndrome, where there is sustained activation of FGF signaling. Knowing more about signaling pathways critical for extraocular muscle function, development, and disease will pave the way for improved treatment options for strabismus patients with FGF abnormalities in craniofacial disease, which also may be applicable to other strabismus patients.

Ophthalmic features of craniosynostosis: A Malaysian experience

BACKGROUND

This study aims to collect local Malaysian data regarding the ophthalmic features and complications in craniosynostosis patients who attended the Combined Craniofacial Clinic (CFC) in University Malaya Medical Centre (UMMC).

METHODS

Retrospective study of medical notes of craniosynostosis patients who attended the CFC in UMMC from 2014 to December 2020.

RESULTS

Out of 37 patients, 29 had syndromic craniosynostosis, and 8 had non-syndromic craniosynostosis. Visual impairment was present in 32.1% of patients. Causes for visual impairment were as follows - amblyopia (25.0%), exposure keratopathy (3.6%), and optic atrophy (3.6%). Hypermetropia and myopia were each seen in 20.6% of patients. Astigmatism was seen in 47.1% of patients, and 29.1% had anisometropia. Proptosis was present in 78.6% and lagophthalmos in 53.3% of patients. Strabismus in primary position occurred in 51.7% of patients. Thirty-one percent of the patients had exposure keratopathy. Optic disc atrophy was seen in 13.7% of patients, and 8.3% had optic disc swelling. Optic disc swelling was resolved in all patients who underwent craniofacial surgery.

CONCLUSION

Our experience in Malaysia was consistent with previously reported data on ophthalmic features of craniosynostosis patients. Additionally, we found that non-syndromic craniosynostosis patients are also at risk of ocular complications just as much as syndromic patients. Appropriate treatment of amblyogenic risk factors, ocular complications, and timely detection of papilledema, and prompt surgical intervention are crucial in preserving long-term visual function in these patients.

Computer tomography-based quantitative analysis of the orbital proptosis severity in infants with syndromic craniosynostosis: case-control study

PURPOSE

Evaluation of orbital proptosis and sutural synostosis pattern along the coronal ring in craniofaciosynostosis patients with or without fibroblastic growth factor receptor 2 (FGFR2) mutation.

METHODS

High-resolution computer tomography was used to assess, in children with or without FGFR2 mutation, the early synostotic involvement of the "major" and "minor" sutures/synchondroses of the coronal arch along with the following orbital parameters: interorbital angle, bone orbital cavity volume, globe volume, ventral globe volume, ventral globe index.

RESULTS

Infants with FGFR2 mutation showed an increased number of closed minor sutures/synchondroses along the posterior coronal branch while both groups showed a comparable synostotic involvement of the minor sutures of the anterior coronal branch. FGFR2 infants with posterior coronal branch synostotic involvement showed a higher degree of proptosis due to both reduced bony cavity volume and increased globe volume (p<0.05).

CONCLUSIONS

Our data show that FGFR2 mutation together with posterior coronal branch synostotic involvement has a synergic effect in causing a more severe degree of orbital proptosis.

Neuro-Ophthalmological Manifestations of Craniosynostosis: Current Perspectives

Craniosynostosis, a premature fusion of cranial sutures that can be isolated or syndromic, is a congenital defect with a broad, multisystem clinical spectrum. The visual pathway is prone to derangements in patients with craniosynostosis, particularly in syndromic cases, and there is a risk for permanent vision loss when ocular disease complications are not identified and properly treated early in life. Extensive advancements have been made in our understanding of the etiologies underlying vision loss in craniosynostosis over the last 20 years. Children with craniosynostosis are susceptible to interruptions in visual input arising from strabismus, refractive errors, and corneal damage; any of these aberrations can result in understimulation of the visual cortex during childhood neurodevelopment and permanent amblyopia. Elevated intracranial pressure resulting from abnormal cranial shape or volume can lead to papilledema and, ultimately, optic atrophy and vision loss. A pediatric ophthalmologist is a crucial component of the multidisciplinary care team that should be involved in the care of craniosynostosis patients and consistent ophthalmologic follow-up can help minimize the risk to vision posed by such entities as papilledema and amblyopia. This article aims to review the current understanding of neuro-ophthalmological manifestations in craniosynostosis and explore diagnostic and management considerations for the ophthalmologist taking care of these patients.

Ophthalmological outcomes of unilateral coronal synostosis in young children

BACKGROUND

To report refractive outcomes, describe types of strabismus and evaluate the outcomes of surgical intervention for unilateral coronal synostosis (UCS) in paediatric patients.

METHODS

This study retrospectively included 30 UCS cases. Patients aged from 3 months to 6 years (median: 1.8 years) were enrolled from January 2018 to December 2019 at Shanghai Children's Hospital. Sixteen patients had all types of strabismus; 15 of these patients underwent surgery.

RESULTS

Refractive errors of 30 cases were included. In 60% of patients, astigmatism of 1.00D or more existed in not less than one eye at last record. Twenty (66.7%) patients had the larger amount of astigmatism in the contralateral eye. Fifteen patients received strabismus surgery, of whom 6 patients with monocular elevation deficiency (MED) underwent the standard Knapp procedure, with or without a horizontal deviation procedure. Fifteen cases were horizontally aligned within 5 prism dioptres (Δ). Six patients with MED (100%) had attained ≥25% elevation improvement after surgery, and the vertical deviation decreased from 25.83 Δ ± 4.92 Δ (range, 20 Δ-30 Δ) to 0.83 Δ ± 4.92 Δ after surgery (range, 0 Δ-10 Δ), for an improvement of 26.67 Δ ± 4.08 Δ (t = 16 P < 0.05). In 1 patient with esotropia, the horizontal deviation decreased from + 80 Δ to + 5 Δ after surgery. One patient was diagnosed with trichiasis and one with contralateral lacrimal duct obstruction.

CONCLUSIONS

Contralateral MED was also the main type of strabismus in UCS. Superior oblique muscle palsy was still the most common, as previously reported. There is a risk of developing a higher astigmatism and anisometropia in the contralateral eye to synostosis. Other ophthalmic disorders should be treated in a timely manner.

TRIAL REGISTRATION

The study was approved by the Institutional Review Board of Shanghai Children's Hospital (approval No. 2020R023-E01) and adhered to the tenets of the Declaration of Helsinki. Ethics approval was procured on March 30, 2020. This was a retrospective study. Written informed consent was sought from the patients' parents or legal guardians. Clinical Trials Registry number: ChiCTR2000034910 . Registration URL: http://www.chictr.org.cn/showproj.aspx?proj=56726 .

Clinical study and some molecular features of Mexican patients with syndromic craniosynostosis

BACKGROUND

Craniosynostosis is one of the major genetic disorders affecting 1 in 2,100-2,500 live newborn children. Environmental and genetic factors are involved in the manifestation of this disease. The suggested genetic causes of craniosynostosis are pathogenic variants in FGFR1, FGFR2, FGFR3, and TWIST1 genes.

METHODS

In order to describe their major clinical characteristics and the presence of pathogenic variants, a sample of 36 Mexican patients with craniosynostosis diagnosed as: Crouzon (OMIM 123,500), Pfeiffer (OMIM 101,600), Apert (OMIM 101,200), Saethre-Chotzen (OMIM 101,400), and Muenke (OMIM 602,849) was analyzed.

RESULTS

In addition to craniosynostosis, most of the patients presented hypertelorism, midface hypoplasia, and abnormalities in hands and feet. To detect the pathogenic variants p.Pro252Arg FGFR1 (OMIM 136,350), p.Ser252Trp, p.Pro253Arg FGFR2 (OMIM 176,943), p.Pro250Arg, FGFR3 (OMIM 134,934), and p.Gln119Pro TWIST1 (OMIM 601,622), PCR amplification and restriction enzyme digestion were performed. Four and two patients with Apert presented the pathogenic variants p.Ser252Trp and p.Pro253Arg in FGFR2, respectively (with a frequency of 11.1% and 5.5%). The p.Pro250Arg pathogenic variant of FGFR3 was found in a patient with Muenke (with a frequency of 2.8%). The above percentages were calculated with the total number of patients.

CONCLUSION

The contribution of this work is discreet, since only 4 genes were analyzed and sample size is small. However, this strategy could be improved by sequencing the FGFR1, FGFR2, FGFR3, and TWIST1 genes, to determine different pathogenic variants. On the other hand, it would be important to include other genes, such as TCF12 (OMIM 600,480), MSX2 (OMIM 123,101), RAB23 (OMIM 606,144), and EFNB1 (OMIM 300,035), to determine their participation in craniosynostosis in the Mexican population.

Evaluation and Management of V pattern Strabismus in Craniosynostosis

V pattern strabismus is the most common ocular motor disorder reported in patients with craniosynostosis. Strabismus management may prove challenging, and few studies provide perspective on surgical approach. The purpose of this review is to discuss evaluation and surgical options for treating V pattern strabismus in patients with craniosynostosis. We provide a step-by-step approach to facilitate surgical planning.