Roman Hossein Khonsari

Hôpital Universitaire Necker - Enfants Malades

Background The pituitary gland is formed by the juxtaposition of two tissues: neuroectoderm arising from the basal diencephalon, and oral epithelium, which invaginates towards the central nervous system from the roof of the mouth. The oral invagination that reaches the brain from the mouth is referred to as Rathke’s pouch, with the tip forming the...

Intentional cranial deformations (ICD) were obtained by exerting external mechanical constraints on the skull vault during the first years of life to permanently modify head shape. The repercussions of ICD on the face are not well described in the midfacial region. Here we assessed the shape of the zygomatic bone in different types of ICDs. We cons...

Polycystin 2 (Pkd2) that belongs to the TRP family, which plays a critical role in development. Pkd2 is mainly localized in the primary cilia that also function as mechanoreceptors in many cells that influence multiple biological processes including Ca2+ influx, chemical activity and signalling pathways. Mutations in many cilia proteins result in c...

A major concern in FGFR2 craniofaciosynostosis is oculo-orbital disproportion, such that orbital malformation provides poor accommodation and support for the orbital contents and peri-orbita, leading to insufficient eyelid closure, corneal exposure and eventually to functional visual impairment. Fronto-facial monobloc osteotomy followed by distract...

Growth and patterning of craniofacial sutures is subjected to the effects of mechanical stress. Mechanotransduction processes occurring at the margins of the sutures are not precisely understood. Here, we propose a simple theoretical model based on the orientation of collagen fibres within the suture in response to local stress. We demonstrate that...

Introduction: Crouzon syndrome is characterised by complex craniosynostosis and midfacial hypoplasia. Where frontofacial monobloc advancement (FFMBA) is indicated, the method of distraction used to achieve advancement holds an element of equipoise. This two-centre retrospective cohort study quantifies the movements produced by internal or external...

The use of non-destructive approaches for digital acquisition (e.g. computerised tomography-CT) allows detailed qualitative and quantitative study of internal structures of skeletal material. Here, we present a new R-based software tool, Icex, applicable to the study of the sizes and shapes of skeletal cavities and fossae in 3D digital images. Trad...

Dysfunction of primary cilia leads to genetic disorder, ciliopathies, which shows various malformations in many vital organs such as brain. Multiple tongue deformities including cleft, hamartoma and ankyloglossia are also seen in ciliopathies, which yield difficulties in fundamental functions such as mastication and vocalization. Here, we found the...

Purpose The aim of this study was to investigate the biomechanics of endoscopically assisted strip craniectomy treatment for the management of sagittal craniosynostosis while undergoing three different durations of postoperative helmet therapy using a computational approach. Methods A previously developed 3D model of a 4-month-old sagittal cranios...

OBJECTIVE Chiari malformation type I (CM-I) is frequent in children and remains a surgical challenge. Several techniques have been described for posterior fossa decompression. No decision algorithm has been validated, and strategies are highly variable between institutions. The goal of this study was to define therapeutic guidelines that take into...

The neonate skull consists of several bony plates, connected by fibrous soft tissue called sutures. Premature fusion of sutures is a medical condition known as craniosynostosis. Sagittal synostosis, caused by premature fusion of the sagittal suture, is the most common form of this condition. The optimum management of this condition is an ongoing de...

Crouzon syndrome with acanthosis nigricans (CAN, a rare type of craniosynostosis characterized by premature suture fusion and neurological impairments) has been linked to a gain-of-function mutation (p.Ala391Glu) in fibroblast growth factor receptor 3 (FGFR3). To characterize the CAN mutation's impact on the skull and on brain functions, we develop...

Background : This study aims to assess the improvement of sleep apnea after secondary Le Fort III facial advancement with distraction (LF3) in faciocraniosynostosis patients with sleep apnea who have previously undergone frontofacial monobloc advancement with distraction (FFMBA). Methods : Patients having undergone secondary LF3 were selected from...

Background/aim: To develop a 3D morphable model of the normal paediatric mandible to analyse shape development and growth patterns for males and females. Methods: Computed tomography (CT) data was collected for 242 healthy children referred for CT scan between 2011 and 2018 aged between 0 and 47 months (mean, 20.6 ± 13.4 months, 59.9% male). Thresh...

Clinical diagnosis of craniofacial anomalies requires expert knowledge. Recent studies have shown that artificial intelligence (AI) based facial analysis can match the diagnostic capabilities of expert clinicians in syndrome identification. In general, these systems use 2D images and analyse texture and colour. They are powerful tools for photograp...

Background This study aims to capture the 3D shape of the human skull in a healthy paediatric population (0–4 years old) and construct a generative statistical shape model. Methods The skull bones of 178 healthy children (55% male, 20.8 ± 12.9 months) were reconstructed from computed tomography (CT) images. 29 anatomical landmarks were placed on t...

Sagittal synostosis is the most occurring form of craniosynostosis, resulting in calvarial deformation and possible long-term neurocognitive deficits. Several surgical techniques have been developed to correct these issues. Debates as to the most optimal approach are still ongoing. Finite element method is a computational tool that’s shown to assis...

The aim of this study was to carry out a retrospective multicenter study comparing the morphological outcome of 8 techniques used for the management of sagittal synostosis versus a large cohort of control patients. Computed tomography (CT) images were obtained from children CT-scanned for non-craniosynostosis related events (n=241) and SS patients...

Sagittal synostosis is the premature fusion of the sagittal suture, affecting 1 in 10,000 live births [1]. Various corrective techniques have been developed. Craniofacial surgeons continue to debate which technique provides the most optimum outcome [2]. Finite element method is a powerful tool used for craniosynostosis management. This study aimed...

Craniosynostosis is the premature fusion of one or more sutures across the calvaria, resulting in morphological and health complications that require invasive corrective surgery. Finite element (FE) method is a powerful tool that can aid with preoperative planning and post-operative predictions of craniosynostosis outcomes. However, input factors c...

‘Bullough lesions’, also referred to as protuberant fibro-osseous lesions (PFOL), are rare temporal bone lesions initially described in 1999. Since only 12 cases have been reported, several key issues, such as their origin and recommended management strategies, remain unresolved. This article reports the largest cohort included in the literature to...

Craniofacial fractures management is challenging to teach due to the complex anatomy of the head, even when using three-dimensional CT-scan images. DIVA is a software allowing the straightforward visualization of CT-scans in a user-friendly three-dimensional virtual reality environment. Here, we assess DIVA as an educational tool for craniofacial t...

Pre-emptive planning to optimize safety and outcome is a defining principle of pediatric craniofacial surgery, in which "procedures that come before" should enhance and not compromise procedures that are planned to follow.A technical modification of fronto-orbital advancement/remodeling in 2-stage hypertelorism surgery for craniofrontonasal dysplas...

Syndromic craniosynostoses are defined by the premature fusion of one or more cranial and facial sutures, leading to skull vault deformation, and midfacial retrusion. More recently, mandibular shape modifications have been described in FGFR-related craniosynostoses, which represent almost 75 % of the syndromic craniosynostoses. Here, further charac...

Objective: The respiratory movements of fetal amniotic fluid are considered to contribute to the growth of the nasal cavities (NC). To assess this functional hypothesis, we considered a group of patients with unilateral choanal atresia (CA) as a model of unilateral absence of amniotic fluid flux in the NC, and compared their NCs shape to age-matche...

Background The study aimed at assessing the variations in thickness of the supra-orbital bar in Crouzon (CS) and Apert syndromes (AS) before and after fronto-facial monobloc advancement (FFMBA) using CT-scan data. Methods All CS or AS patients who underwent FFMBA between 2008 and 2018 with available clinical and CT-scan data were included. Frontal...

Introduction Ophthalmological involvement in anterior plagiocephaly (AP) due to unicoronal synostosis (UCS) raises management challenges. Two abnormalities of the extraocular muscles (EOM) are commonly reported in UCS without objective quantification: (1) excyclorotation of the eye and (2) malposition of the trochlea of the superior oblique muscle....

Gnathodiaphyseal Dysplasia (GDD) is a rare, often misdiagnosed, autosomal-dominant disorder due to point mutations in the ANO5 gene. GDD combines craniofacial fibro-osseous lesions, dental loss and progressive curvature and cortical thickening of long bones and vertebra, causing pathological fractures. Diagnosis is based on bone pathology and mutat...

Background: Orbital anomalies are a central clinical concern in Crouzon syndrome. In this study, the authors assessed the volume and shape of the orbits in a series of patients with Crouzon syndrome treated using frontofacial monobloc advancement with internal distraction, and provide quantitative time-related data on orbital shape. Methods: Twenty...

The vault of the skull is a region of the neurocranium formed by a process of membranous ossification. It consists of several bones: frontal bone, parietal bone, squamous part of the temporal bone, lamina ascendens of the sphenoid, and interparietal bone. The embryological origin of the bones of the skull vault is still the subject of controversy....

The digital revolution has led to many recent developments in implantology that have considerably facilitated implant planning and the creation of surgical guides. The purpose of this article is to explain how we set up a digital workflow in a large city hospital and how we met the requirements of the European regulations on the production of custo...

Secondary surgeries for single craniosynostosis surgeries are mainly esthetic refinements rather than functional indications. However, cranioplasties for bone defects correction or insufficient corrections may be undertaken. Management of syndromic craniosynostoses usually requires multiple surgical interventions, the sequence of which might vary p...

Résumé La déformation nasale résiduelle chez les patients porteurs de fente labiopalatine reste la demande principale de ces derniers. La réalisation d’une chirurgie primaire nasale a considérablement amélioré les résultats. Cependant, il est encore souvent nécessaire d’améliorer la morphologie nasale. Le respect des tissus lors de la chirurgie pri...

The authors report an unusual case of penetrating anterior neck injury in a 71-year-old female patient, who intentionally stabbed herself in a suicide attempt. The initial clinical and radiological assessment revealed that the knife had pierced through the sixth vertebral body and spinal cord, avoiding all the vital structures on the way. Surgical...

Rituximab, an anti-CD20 monoclonal antibody, is an effective treatment for rheumatoid arthritis. Here we report the case of a patient with rheumatoid arthritis, having taken risedronate for 14 months to prevent corticosteroid-induced osteoporosis, more than 2 years ago, who presented osteonecrosis of jaw following herpetic gingivostomatitis two wee...

Background: Gorham-Stout disease (GSD) is a rare lymphatic disorder which results in bone destruction. Defects of the skull base are difficult to manage, we describe cases to better understand the disease and discuss treatment. Methods: Retrospective study including all patients treated for GSD skull-base defects. Medical records, clinical, imag...

The Iraq-Iran war (1980-88) resulted in numerous maxillofacial injuries. More than 400,000 people were wounded and required specialist care. Paul Tessier, a leading French plastic surgeon and pioneering craniofacial surgeon, was involved in several missions to Iran and operated on a vast cohort of patients with complex war trauma sequelae. Our stud...

Aim and scope: Artificial intelligence (AI) in medicine is a fast-growing field. The rise of deep learning algorithms, such as convolutional neural networks (CNNs), offers fascinating perspectives for the automation of medical image analysis. In this systematic review article, we screened the current literature and investigated the following quest...

Introduction: Cleft lip and palate (CLP) surgery interferes with maxillary growth and contributes to transversal and sagittal growth impairment. Our retrospective descriptive study aimed to evaluate maxillary bone shape in a homogenous unilateral CLP patient group using geometric morphometrics based on CT-scan data. Material and methods: We incl...

Introduction: Cephalometry performed on sagittal teleradiographic X-rays is commonly used for the planification of orthognathic procedures. Tomographic imaging techniques (computer tomography or cone-beam computer tomography) are more and more prescribed for the assessment of complex occlusofacial anomalies. In this study, we intended to evaluate...

Purpose: Parry Romberg syndrome (PRS) is a condition characterized by progressive hemifacial atrophy, predominantly affecting the soft tissues. Associated bone retraction is a common clinical feature of PRS but has never been assessed. Here we used 3D imaging and Bayesian statistics in order to demonstrate and quantify bone atrophy in PRS. Materi...

Schwannomas are benign peripheral nerve sheath tumors originating from the Schwann cells. Most schwannomas in the head and neck region are solitary; however, multiple schwannomas affecting one or more nerves suggest a possible association with neurofibromatosis type 2 and schwannomatosis. Plexiform schwannoma is a rare variant of conventional schwa...

Introduction Primary failure of eruption (PFE) is a sporadic or inherited disorder of dental eruption that can be caused by mutations in the PTH1R gene. PFE typically manifests as a severe posterior open bite. Orthodontic treatment is considered ineffective in PFE. Case presentation Here we report 2 unrelated PTH1R‐negative cases of severe eruptio...

Aim and scope: Result assessment in cleft surgery is a technical challenge and requires the development of dedicated morphometric tools. Two cohorts of patients managed according to two different protocols were assessed at similar ages and their palatal shape was compared using geometric morphometrics. Material and methods: Ten patients (protoco...

Background: In FGFR2 craniosynostosis, midfacial hypoplasia features oculo-orbital disproportion and symptomatic exorbitism. Clinical consequences may mandate surgery at a young age to prevent globe subluxation, corneal ulceration, and potential loss of vision. Monobloc osteotomy and distraction osteogenesis (monobloc distraction) seek to correct...

The development of the craniofacial skeleton is a spatial and temporal process where cranial sutures play a role in the regulation of morphogenesis and growth. Disruption of these cellular and molecular interactions may lead to craniosynostosis, the premature obliteration of one or more cranial sutures, yielding skull growth restriction and malform...

Splints are commonly used after primary cleft surgery in order to secure the position of the nasal cartilages. Although the importance of splints is more and more stressed in the literature, many questions remain unanswered relative to the psychological impact of this device on children and families. Two questionnaires, Information and Tolerance, w...

The Musée Dupuytren was a Parisian pathology museum established in 1835. This museum hosted 3 skulls with severe craniofacial lesions initially tagged as aggressive forms of tinea capitis. The aim of this study was to investigate these specimens and discuss the initial diagnosis. Historical investigations were conducted based on the biographic data...

Background Fibroblastic connective tissue nevi (FCTN) are benign skin conditions characterized by bland spindle cells infiltrating the reticular dermis and the upper subcutis with preservation of adnexal structures. A subset of FCTN expresses CD34, which may cause difficulties in the differential diagnosis, in particular with dermatofibrosarcoma (D...

Subperiosteal implant denture therapy was initially introduced in 1942 in Sweden and was then used worldwide for the treatment of fully edentulous maxillary or mandibular arches with advanced bone atrophy. Most authors describe decent success rates for mandibular subperiosteal implants in cases with major bone atrophy but follow-up studies for maxi...