Progressive synosteosis in Apert's syndrome (acrocephalosyndactyly), with a description of roentgenographic changes in the feet

[The Apert Foot: Anatomical Changes, Classification, Thoughts on surgical Treatment]

Diagnosis and therapy of the Apert foot are scarcely described in extant literature. This article describes anatomical changes observed in 30 Apert feet. By analysis of X-rays and computed scans 5 types of bony Apert foot malformations were identified. We developed therapeutic recommendations based on this classification.

Is the Apert foot an overlooked aspect of this rare genetic disease? Clinical findings and treatment options for foot deformities in Apert syndrome

BACKGROUND

Apert syndrome is characterised by the presence of craniosynostosis, midface retrusion and syndactyly of hands and feet, thus, synonymously referred to as acrocephalosyndactyly type I. Considering these multidisciplinary issues, frequently requiring surgical interventions at an early age, deformities of the feet have often been neglected and seem to be underestimated in the management of Apert syndrome. Typical Apert foot features range from complete fusion of the toes and a central nail mass to syndactyly of the second to fifth toe with a medially deviated great toe; however, no clear treatment algorithms were presented so far. This article reviews the current existing literature regarding the treatment approach of foot deformities in Apert syndrome.

STATE-OF-THE-ART TOPIC REVIEW

Overall, the main focus in the literature seems to be on the surgical approach to syndactyly separation of the toes and the management of the great toe deformity (hallux varus). Although the functional benefit of syndactyly separation in the foot has yet to be determined, some authors perform syndactyly separation usually in a staged procedure. Realignment of the great toe and first ray can be performed by multiple means including but not limited to second ray deletion, resection of the proximal phalanx delta bone on one side, corrective open wedge osteotomy, osteotomy of the osseous fusion between metatarsals I and II, and metatarsal I lengthening using gradual osteodistraction. Tarsal fusions and other anatomical variants may be present and have to be corrected on an individual basis. Shoe fitting problems are frequently mentioned as indication for surgery while insole support may be helpful to alleviate abnormal plantar pressures.

CONCLUSION

There is a particular need for multicenter studies to better elaborate surgical indications and treatment plans for this rare entity. Plantar pressure measurements using pedobarography should be enforced in order to document the biomechanical foot development and abnormalities during growth, and to help with indication setting. Treatment options may include conservative means (i.e. insoles, orthopedic shoes) or surgery to improve biomechanics and normalize plantar pressures.

LEVEL OF EVIDENCE

Level V.

Talocalcaneal coalition in Muenke syndrome: report of a patient, review of the literature in FGFR-related craniosynostoses, and consideration of mechanism

Muenke syndrome is an autosomal dominant craniosynostosis syndrome resulting from a defining point mutation in the Fibroblast Growth Factor Receptor3 (FGFR3) gene. Muenke syndrome is characterized by coronal craniosynostosis (bilateral more often than unilateral), hearing loss, developmental delay, and carpal and/or tarsal bone coalition. Tarsal coalition is a distinct feature of Muenke syndrome and has been reported since the initial description of the disorder in the 1990s. Although talocalcaneal coalition is the most common tarsal coalition in the general population, it has never previously been reported in a patient with Muenke syndrome. We present a 7-year-old female patient with Muenke syndrome and symptomatic talocalcaneal coalition. She presented at the age of 7 with limping, tenderness and pain in her right foot following a fall and strain of her right foot. She was treated with ibuprofen, shoe inserts, a CAM walker boot, and stretching exercises without much improvement in symptoms. A computed tomography (CT) scan revealed bilateral talocalcaneal coalitions involving the middle facet. She underwent resection of the talocalcaneal coalitions, remaining pain-free post-operatively with an improvement in her range of motion, gait, and mobility. This report expands the phenotype of tarsal coalition in Muenke syndrome to include talocalcaneal coalition. A literature review revealed a high incidence of tarsal coalition in all FGFR related craniosynostosis syndromes when compared to the general population, a difference that is statistically significant. The most common articulation involved in all syndromic craniosynostoses associated with FGFR mutations is the calcaneocuboid articulation.

Impact of genetics on the diagnosis and clinical management of syndromic craniosynostoses

PURPOSE

More than 60 different mutations have been identified to be causal in syndromic forms of craniosynostosis. The majority of these mutations occur in the fibroblast growth factor receptor 2 gene (FGFR2). The clinical management of syndromic craniosynostosis varies based on the particular causal mutation. Additionally, the diagnosis of a patient with syndromic craniosynostosis is based on the clinical presentation, signs, and symptoms. The understanding of the hallmark features of particular syndromic forms of craniosynostosis leads to efficient diagnosis, management, and long-term prognosis of patients with syndromic craniosynostoses.

METHODS

A comprehensive literature review was done with respect to the major forms of syndromic craniosynostosis and additional less common FGFR-related forms of syndromic craniosynostosis. Additionally, information and data gathered from studies performed in our own investigative lab (lab of Dr. Muenke) were further analyzed and reviewed. A literature review was also performed with regard to the genetic workup and diagnosis of patients with craniosynostosis.

RESULTS

Patients with Apert syndrome (craniosynostosis syndrome due to mutations in FGFR2) are most severely affected in terms of intellectual disability, developmental delay, central nervous system anomalies, and limb anomalies. All patients with FGFR-related syndromic craniosynostosis have some degree of hearing loss that requires thorough initial evaluations and subsequent follow-up.

CONCLUSIONS

Patients with syndromic craniosynostosis require management and treatment of issues involving multiple organ systems which span beyond craniosynostosis. Thus, effective care of these patients requires a multidisciplinary approach.

Hands and feet in the Apert syndrome

We studied 44 pairs of hands and 37 pairs of feet in Apert syndrome, utilizing clinical, dermatoglyphic, and radiographic methods. We also studied histologic sections of the hand from a 31-week stillborn fetus. Topic headings discussed include: clinical classification of syndactyly; correlations between types of hands and feet in the same patient; dermatoglyphics; anatomy of the hand; radiologic assessment; comparison with other studies; histologic assessment of the hand; acrocephalosyndactyly vs. acrocephalopolysyndactyly: a pseudodistinction; and some generalizations.

Spatial dysmorphology of the foot in Apert syndrome: three-dimensional computed tomography

Computer assisted medical imaging was used to define the spatial dysmorphology of the foot in three patients with Apert syndrome and to correlate that dysmorphology with ambulation and footwear. Thin slice (2 mm), abutting, high resolution axial computed tomography (CT) foot scans were obtained. The CT data were post processed, using Analyze, to generate three-dimensional surface shaded and volumetric reformations. The reformatted images were evaluated by a bone and joint radiologist to identify abnormalities of bone shape, size, and orientation, of joint morphology, and of the foot as a whole. Five consistent findings were observed among the three pairs of feet: (1) anomalous great toes with phalangeal and metatarsal pathology; (2) simple syndactyly of toes 2-5; (3) fusions between matatarsals; (4) tarsal coalitions; and (5) limitations in commercial footwear. One patient underwent bilateral fifth metatarsal wedge osteotomies to facilitate the wearing of shoes. The dysmorphology of the Apert foot is a combination of congenital malformations and postnatal deformations, secondary to progressive synostosis. Prophylactic foot surgery may be indicated in Apert patients to facilitate shoe fitting.

Phenotypic variation in acrocephalosyndactyly syndromes: unusual findings in patient with features of Apert and Saethre-Chotzen syndromes

The acrocephalosyndactyly syndromes have presented diagnostic challenges because of overlap in their clinical manifestations. We present a patient with features most suggestive of Apert syndrome, but with a pattern of syndactyly not previously described. In contrast to the complex syndactyly reported as a universal feature of this syndrome, this patient shows close to total simple syndactyly of the index through ring fingers of each hand. Differential diagnoses are discussed. Because the features are reminiscent of Apert syndrome, we suggest that a new classification of hand morphology should be added to include the pattern described here.

Upper and lower airway compromise in the Apert syndrome

Both upper and lower airway compromise may be responsible for early death in some patients with the Apert syndrome. We report on two and review six cases with complete or partial cartilage sleeve abnormalities of the trachea. Possible mechanisms include tracheal stenosis and/or lack of tracheal distensibility which may result in respiratory inefficiency, inability to clear secretions, and/or increased liability to surface injury from tracheal suctioning. Upper airway compromise, consisting of obstructive sleep apnea and cor pulmonale, may result from reduced nasopharyngeal and oropharyngeal dimensions in the Apert craniofacial configuration.

Cervical spine in the Apert syndrome

Radiographs of the cervical spine--in many cases longitudinal--were available for study in 68 cases of Apert syndrome. Autopsy material was available in one of these cases, and a 3-dimensional reconstruction from a CT scan was also studied in one case. Variable degrees of fusion were observed, involving the articular facets, the neural arch or transverse processes, or block fusion of the vertebral bodies. Ossification may not always be evident in some early radiographs. However, early radiographic signs of impending fusion may be irregularity in vertical orientation of the vertebral bodies and narrowing of the involved intervertebral spaces. Cervical fusions occurred in 68%, single fusions being found in 37%, and multiple fusions in 31%. C5-C6 fusion was most common, alone or in combination with other fusions. In contrast, cervical fusions are known to occur in 25% of Crouzon patients, most commonly involving C2-C3 only. It appears that when fusions are present, C5-C6 involvement in the Apert syndrome and C2-C3 involvement in the Crouzon syndrome separate the 2 conditions in most cases. Because cervical anomalies may complicate an already compromised airway in any form of acrocephalosyndactyly, it is imperative to initiate radiographic study of the cervical spine before undertaking anesthesia for surgery.

Congenital craniofacial anomalies of ophthalmic importance

Congenital craniofacial abnormalities frequently require ophthalmic evaluation and surgical management. Called upon to perform as part of the craniofacial team managing the often severely deformed craniofacial patient, the ophthalmologist must bring a basic knowledge of craniofacial syndromes and developmental anatomy, as well as clinical acumen to help preserve or improve ocular and adnexal function. As an introduction to this area of ophthalmology, the clinical features, classification, appropriate facial embryology, assessment and surgical considerations of the various congenital craniofacial abnormalities are reviewed. The expanding availability of craniofacial surgeons and surgical teams along with improved surgical results will ultimately require an increasing involvement by many more ophthalmologists in the evaluation and management of these congenital abnormalities.

Apert syndrome associated with septo-optic dysplasia

Apert syndrome and septo-optic dysplasia are rare congenital structural disorders which have not been associated previously; we report a female infant with this association. Brain sonography and computed tomography revealed agenesis of the septum pellucidum; optic hypoplasia was demonstrated by funduscopic evaluation. We postulate that an embryopathic factor, which manifests at 5-6 weeks gestation, may result in this new association. Transverse craniectomy was performed in the hope of preserving brain development. Neither hypopituitarism nor adrenal insufficiency was observed; however, clinical manifestations and laboratory data provided evidence of inappropriate antidiuretic hormone syndrome.

Apert's syndrome--a report of five cases

This report presents five cases of Apert's syndrome with features of acrocephaly, characteristic face and complete syndactyly of the hand and foot with bony fusion. Three cases out of five showed preaxial polydactylies of the foot, considered to be one of the characteristic features of Carpenter's syndrome. In the remaining two cases, the first digital ray of the foot was broad and deformed. In addition one case had a postaxial polydactyly of the hand. Three cases showed severe deformity of the shoulder; two had dysplasia and one had synchondrosis of the glenohumeral joint. On the basis of our findings in this, we feel that there is much phenotypic overlap between Apert's and Carpenter's syndrome. A polydactylous presentation of the hand and foot can be found in not a few cases of Apert's syndrome and it is not always an exclusive feature of Carpenter's syndrome.

Syndromology's message for craniofacial biology

Syndromology is a misunderstood specialty that has much to contribute to the understanding of cranio-facial biology in general and the study of craniofacial anomalies in particular. An introduction to the practice of syndromology and the rudiments of syndrome delineation is presented. The aetiology and pathogenesis of selected craniofacial anomalies (Robin complex, hemifacial microsomia, and craniosynostosis) are considered from the perspective of syndromology.

Syndrome designations

Because syndrome designations permit the collection of data, they are much more than just lables. As new syndromes become delineated, their names connote (1) their phenotypic spectra, (2) their natural histories, and (3) their modes of inheritance or risk of recurrence. Various methods for designating new syndromes are reviewed, including naming them after (1) the basic defect, (2) an eponym, (3) one or more striking features, (4) an acronym, (5) a numeral, (6) a geographic term, and (7) some combination of the above. None of these systems of nomenclature is without fault. The advantages and disadvantages of each are discussed.