Atypical sagittal suture craniosynostosis: pathological considerations for early closure of the anterior part of the sagittal suture.

Sagittal suture synostosis is one of the most common craniosynostoses and is often diagnosed by characteristic narrow and long skull shape, scaphocephaly. However, some patients with sagittal suture synostosis do not present with typical scaphocephaly, making early diagnosis difficult. In this study, five cases of characteristic skull deformity showing a narrowing of the cranium posterior to the coronal suture on computed tomography (CT) are presented. The three older children presented with papilledema and intellectual disability and a closed sagittal suture on CT. The two infant cases were diagnosed with the characteristic cranial deformities with aggravation of the deformity over time, but sagittal suture closure was not evident on CT. All patients underwent cranial remodeling surgery. In the two infant cases, the histopathological findings showed that the anterior part of the sagittal suture was firmly fused with fibrous tissue without bony fusion. These findings suggested that narrowing of the cranium posterior to the coronal suture might be due to functional fusion of the anterior portion of the sagittal suture prior to bony fusion. In an infant presenting with such a deformity that shows aggravation of the deformity over time, surgical treatment should be considered.

The current understanding of germline predisposition in non-syndromic sagittal craniosynostosis: a systematic review.

PURPOSE: The objective of this literature review was to provide a comprehensive and up-to-date overview of the current understanding of the genetic etiology for non-syndromic sagittal craniosynostosis. METHODS: Using the PubMed database and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), we systematically reviewed relevant records on germline genetics in children with non-syndromic sagittal craniosynostosis. RESULTS: Two hundred two records were identified, of which 25 were included following title and abstract screening and subsequent full-text review. The 25 records in combination included 829 children with non-syndromic sagittal craniosynostosis. A likely pathogenic or pathogenic germline variant was reported for 9.8% of the 827 patients for whom germline genetic testing was performed. The reported variants were distributed across 50 different genes, with more than one variant detected in 13 genes. CONCLUSION: Based on the existing literature, genetic predisposition is likely to play a role in at least 9% of children with non-syndromic sagittal craniosynostosis. Future studies will benefit from international consensus in terms of diagnostic nomenclature and a higher level of standardization across study methodologies and bioinformatic approaches.

Endoscopic treatment of sagittal suture synostosis - a critical analysis of current management strategies.

While many centers nowadays offer minimally invasive techniques for the treatment of single suture synostosis, surgical techniques and patient management vary significantly. We provide an overview of how scaphocephaly treated with endoscopic techniques is managed in the reported series and analyze the crucial steps that need to be dealt with during the management process. We performed a review of the published literature including all articles that examined sagittal-suture synostosis treated with endoscopic techniques as part of single- or multicenter studies. Fourteen studies reporting results of 885 patients were included. We identified 5 key steps in the management of patients. A total of 188 patients were female and 537 male (sex was only specified in 10 articles, for 725 included patients, respectively). Median age at surgery was between 2.6 and 3.9 months with a total range from 1.5 to 7.0 months. Preoperative diagnostics included clinical and ophthalmologic examinations as well as neuropsychological and genetic consultations if needed. In 5 publications, a CT scan was routinely performed. Several groups used anthropometric measurements, mostly the cephalic index. All groups analyzed equally recommended to perform endoscopically assisted craniosynostosis surgery with postoperative helmet therapy in children < 3 months of age, at least for non-syndromic cases. There exist significant variations in surgical techniques and patient management for children treated endoscopically for single suture sagittal synostosis. This heterogeneity constitutes a major problem in terms of comparability between different strategies.

A case of early obliteration of the sagittal suture without effect on cranial deformation.

This paper describes a unique case of craniosynostosis in a female skull in which sagittal sutures were completely fused by adolescence. Despite sagittal synostosis, the skull was of normal shape and size. Regarding craniometric features, the synostotic normocephalic skull was markedly different than that of scaphocephalic skulls which typically result from premature obliteration of the sagittal suture.

Improved cephalic index following early cranial vault remodeling in patients with isolated nonsyndromic sagittal synostosis.

OBJECTIVE: Isolated nonsyndromic sagittal synostosis (SS) is the most common form of craniosynostosis in children, accounting for approximately 60% of all craniosynostoses. The typical cranial measurement used to define and follow SS is the cephalic index (CI). Several surgical techniques have been suggested, but agreement on type and timing of surgery is lacking. This study aimed to evaluate the authors' institutional experience of surgically treating SS using a modified subtotal cranial vault remodeling technique in a population-based cohort. Special attention was directed toward the effect of patient age at time of surgery on long-term CI outcome. METHODS: A retrospective analysis was conducted on all patients with isolated nonsyndromic SS who were surgically treated from 2003 to 2011. Data from electronic medical records were gathered. Eighty-two patients with SS were identified, 77 fulfilled inclusion criteria, and 72 had sufficient follow-up data and were included. CI during follow-up after surgery was investigated with ANOVA and a linear mixed model. RESULTS: In total, 72 patients were analyzed, consisting of 16 females (22%) and 56 males (78%). The mean ± SD age at surgery was 4.1 ± 3.1 months. Blood transfusions were received by 81% of patients (26% intraoperatively, 64% postoperatively, 9% both). The mean ± SD time in the pediatric ICU was 1.1 ± 0.25 days, and the mean ± SD total hospital length of stay was 4.6 ± 2.0 days. No patient required reoperation. The mean ± SD CI increased from 69 ± 3 to 87 ± 5 for patients who underwent surgery before 45 days of age. Surgery resulted in a larger increase in CI for patients who underwent surgery at a younger age compared with older patients (p < 0.05, Tukey's HSD test). In the comparison of patients who underwent surgery before 45 days of age with patients who underwent surgery at 45-90, 90-180, and more than 180 days of age, the linear mixed model estimated a long-term loss of CI of 3.0, 5.5, and 7.4 points, respectively. CONCLUSIONS: The modified subtotal cranial vault remodeling technique used in this study significantly improved CI in patients with SS. The best results were achieved when surgery was performed early in life.

ROCK-TAZ signaling axis regulates mechanical tension-induced osteogenic differentiation of rat cranial sagittal suture mesenchymal stem cells.

Mechanical force across sutures is able to promote suture osteogenesis. Orthodontic clinics often use this biological characteristic of sutures to treat congenital cranio-maxillofacial malformations. However, the underlying mechanisms still remain poorly understood. Craniofacial sutures provide a special growth source and support primary sites of osteogenesis. Here, we isolated rat sagittal suture cells (rSAGs), which had mesenchymal stem cell characteristics and differentiating abilities. Cells were then subjected to mechanical tension (5% elongation, 0.5 Hz; sinusoidal waveforms) showing that mechanical tension could enhance osteogenic differentiation but hardly affect proliferation of rSAGs. Besides, mechanical tension could increase Rho-associated kinase (ROCK) expression and enhance transcriptional coactivator with PDZ-binding motif (TAZ) nuclear translocation. Inhibiting ROCK expression could suppress tension-induced osteogenesis and block tension-induced upregulation of nuclear TAZ. In addition, our results indicated that TAZ had direct combination sites with runt-related transcription factor 2 (Runx2) in rSAGs, and knock-downed TAZ simultaneously decreased the expression of Runx2 no matter with or without mechanical tension. In summary, our findings demonstrated that the multipotency of rSAGs in vitro could give rise to early osteogenic differentiation under mechanical tension, which was mediated by ROCK-TAZ signal axis.

[Endoscopic treatment of nonsyndromic sagittal craniosynostosis in dizygotic twins. A case report and literature review]. / Éndoskopicheskoe lechenie nesindromal'nogo sagittal'nogo kraniosinostoza u dizigotnykh bliznetsov (dvoinia). Klinicheskii sluchai i obzor literatury.

The article presents a rare clinical case of isolated sagittal craniosynostosis in dichorionic diamniotic twins. The review addresses issues of epidemiology, etiology, and pathogenesis of craniosynostosis in this group of patients.

Craniofacial cephalometric morphology in 8-year-old children with operated sagittal synostosis.

OBJECTIVES: To evaluate cephalometrically craniofacial morphology in children with operated sagittal synostosis and to compare the findings with age- and sex-matched controls. SETTING AND SAMPLE POPULATION: Forty-two children (37 boys) with operated primary sagittal synostosis were compared retrospectively with age- and sex-matched controls from lateral cephalograms taken at a mean age of 8.1 (range 7.0-8.9) years. MATERIAL AND METHODS: The operations had been performed between the ages of 2 months and 6.3 years at three Finnish hospitals. The surgical methods included strip craniectomy, pi-plasty and cranial vault expansion. A paired Student's t-test and Pearson's correlation analysis were used in the statistical analyses. RESULTS: Children with operated sagittal synostosis had wide cranial base angles and their mandibles were retrognathic with labially inclined lower incisors relative to the controls. Age at craniosynostosis operation did not correlate with the cranial base angle. CONCLUSION: This study suggests that children with operated sagittal synostosis have minor distinctive morphological features in the cranial base and mandible. Orthodontic evaluation of craniofacial growth is recommended.

Whole genome sequencing identifies associations for nonsyndromic sagittal craniosynostosis with the intergenic region of BMP2 and noncoding RNA gene LINC01428.

Craniosynostosis (CS) is a major birth defect resulting from premature fusion of cranial sutures. Nonsyndromic CS occurs more frequently than syndromic CS, with sagittal nonsyndromic craniosynostosis (sNCS) presenting as the most common CS phenotype. Previous genome-wide association and targeted sequencing analyses of sNCS have identified multiple associated loci, with the strongest association on chromosome 20. Herein, we report the first whole-genome sequencing study of sNCS using 63 proband-parent trios. Sequencing data for these trios were analyzed using the transmission disequilibrium test (TDT) and rare variant TDT (rvTDT) to identify high-risk rare gene variants. Sequencing data were also examined for copy number variants (CNVs) and de novo variants. TDT analysis identified a highly significant locus at 20p12.3, localized to the intergenic region between BMP2 and the noncoding RNA gene LINC01428. Three variants (rs6054763, rs6054764, rs932517) were identified as potential causal variants due to their probability of being transcription factor binding sites, deleterious combined annotation dependent depletion scores, and high minor allele enrichment in probands. Morphometric analysis of cranial vault shape in an unaffected cohort validated the effect of these three single nucleotide variants (SNVs) on dolichocephaly. No genome-wide significant rare variants, de novo loci, or CNVs were identified. Future efforts to identify risk variants for sNCS should include sequencing of larger and more diverse population samples and increased omics analyses, such as RNA-seq and ATAC-seq.

Vertex epidural hematoma: Diagnosis, therapeutic consideration and outcome.

OBJECTIVE: Vertex epidural hematoma (VEDH) is a relatively uncommon type of intracranial hematoma. Because of its unique location and the potential of massive intraoperative bleeding, diagnosis and surgical intervention of VEDH may be challenging. MATERIALS AND METHODS: A retrospective analysis of 32 patients with VEDH was undertaken to investigate the prognostic factor and therapeutic strategy of VEDH. Special attention was paid to the relationship between fracture pattern, surgical method, intraoperative blood loss and outcome. RESULTS: Patients treated surgically had a higher percentage of consciousness disturbance and a significantly larger size of VEDH compared with patients treated conservatively (p = 0.029 and p < 0.0001, respectively). Bleeding from the injured superior sagittal sinus (SSS) was noted in six of nine patients (67%) with a linear fracture parallel to the SSS. Only one patient (20%) with a linear fracture crossing the SSS had bleeding from the injured SSS. Five of eight patients (63%) with sagittal suture diastasis experienced bleeding from the SSS. All patients with massive blood loss and six of seven patients developing intraoperative shock had copious bleeding from the injured SSS. All patients with intraoperative massive bleeding and shock underwent traditional "simple craniotomy". No patients undergoing "strip craniotomy" experienced massive bleeding. Thrombocytopenia (p = 0.008), headache (p = 0.015), consciousness disturbance (p = 0.043), pupil reactivity (p = 0.010), GCS score (p < 0.0001) and the relationship between skull fracture and the SSS (p = 0.037) were significant prognostic factors. CONCLUSION: Our study demonstrated GCS score may be a significant prognostic factor in patients with VEDH. Bleeding from the injured SSS occurred frequently in VEDH patients with a linear skull fracture parallel to the SSS or sagittal suture diastasis and could cause devastating hemorrhage. When operating on such patients, the surgical team should prepare for the possibility of massive blood loss and intraoperative shock. Bilateral parasagittal craniotomies with preservation of a central bone strip containing the sagittal suture (strip craniotomy) to allow application of tack-up sutures from the dura to the bone strip may be more suitable for VEDH evacuation.

Single sagittal craniosynostosis surgical treatment with the "Peau d́ours" technique. Single-center experience in Mexico.

Scaphocephaly (SC) is defined as an elongation of the anteroposterior axis of the skull resulting from the abnormal fusion of the sagittal suture. This study describes the "Peau d'ours" technique and results for correcting SC. We conducted a consecutive and retrospective analysis of patients treated from 2011 to 2016. We evaluated the gender, age, and surgical outcomes. A total of 53 patients were enrolled with a mean age of 19 months old. The advantages of this technique are healthy coronal and lambdoid suture preservation and symmetrical parietal bone flap opening. This technique is safe and simple to reproduce, allowing good surgical outcomes with a low incidence of secondary craniosynostosis. This technique is ideal for patients older than six months old.

Anatomical observation and significance of the parietal foramen in Chinese adults.

BACKGROUND: This study aimed to investigate the incidence, number, diameter, and relative location of the parietal foramen (PF) as well as communication of intracranial and extracranial orifices and their direction, and sagittal suture morphology and length. MATERIALS AND METHODS: A total of 280 dry Chinese adult skull specimens from the Department of Anatomy, Southern Medical University, were observed and measured. The occurrence rate and quantity of the PF near the sagittal suture were recorded. The aperture of the PF, the vertical distance between PF and sagittal suture, and the linear distance between PF and lambda were measured using a Vernier calliper. The length of the sagittal suture was measured by a flexible ruler; the direction and communication of intracranial and extracranial orifices were detected using a probe. RESULTS: The total incidence of the PF was 82.86%, slightly higher on the right side than on the left side. The single-foramen type was the most prevalent. The mean diameter of the PF on the left and right sides were 1.02 ± 0.72 mm and 1.07 ± 0.67 mm, respectively, and the diameter of the PF on the sagittal suture was 1.77 ± 0.44 mm. The mean vertical distance between the PF and the sagittal suture was 5.90 ± 2.78 mm and 5.85 ± 2.75 mm on the left and right sides, respectively. The shape of the sagittal suture in the PF area was primarily dentate shaped, with an average arc length of χ = 124.36 ± 7.76 mm, of which the majority were completely healed type. The intracranial and extracranial communication was 39.97%, and the majority of the PF were anteromedial direction. CONCLUSIONS: The current study provided an anatomical basis for imaging diagnosis and neurosurgery by investigating the incidence, diameter, and relative location of the PF and intracranial and extracranial communication and direction.

Sagittal suture morphological variation in human archaeological populations.

Cranial sutures join the many bones of the skull. They are therefore points of weakness and consequently subjected to the many mechanical stresses affecting the cranium. However, the way in which this impacts their morphological complexity remains unclear. We examine the intrinsic and extrinsic mechanisms of human sagittal sutures by quantifying the morphology from 107 individuals from archaeological populations spanning the Mesolithic to Middle ages, using standardized two-dimensional photographs. Results show that the most important factor determining sutural complexity appears to be the position along the cranial vault from the junction with the coronal suture at its anterior-most point to the junction with the lambdoid suture at its posterior-most point. Conversely, factors such as age and lifeways show few trends in complexity, the most significant of which is a lower complexity in the sutures of Mesolithic individuals who consumed a tougher diet. The simple technique used in this study therefore allowed us to identify that, taken together, structural aspects play a more important role in defining the complexity of the human sagittal suture than extrinsic factors such as the mechanical forces imposed on the cranium by individuals' diet.

Complete sagittal suture closure evaluation based on post mortem computed tomography.

Age assessment at the time of death is of great importance when an unidentified skeleton or corpse is found. Obliteration of cranial sutures has been used for age assessment regarding anthropology as non - metrical method of direct bone inspection. The aim of our study was to assess sagittal suture closure in the contemporary population of Polish men using postmortem computed tomography. A total of 255 male skulls were analyzed with the use of multiplanar reconstruction (MPR) and volume rendering technique (VRT) images, which were based on whole-body postmortem computed tomography scans. The individuals of Polish origin were of precisely known metrical age. The sagittal sutures were analyzed across their entire thickness (including both the outer and inner aspect of bone) and along their entire length via frontal sections, using the sagittal suture division into 4 segments. This study showed that the earliest signs of suture closure occur in S4 on the inner side of the calvaria at a mean age of 50.48 years, but the youngest person with starting obliteration process was 13.37 years. This is prove that exist variability which must be count during biological age estimation. Additionally, VRT visualisation shows that the fourth state of obliteration does not mean that obliteration was ended. Further analyses of cranial suture closure are needed to obtain reliable methods for postmortem estimation of the age at the time of death in contemporary populations. The use of postmortem computed tomography may offer additional opportunities for contemporary analysis of skeletal material.

Parietal foramen: incidence and topography.

BACKGROUND: The parietal foramen (PF) is a small inconsistent aperture located at the border of the middle 1/3 and posterior 1/3 of the parietal bone near the sagittal suture and is considered an emissary foramen. Cranial emissary foramina are of utmost importance due to the structures that traverse the foramen. Variations in these foramina are common. Knowledge of the PF is important when performing neurosurgical procedures as the emissary vessels are at risk. MATERIALS AND METHODS: The present study used 100 dry adult calvaria to determine the frequency of PF, the diameter of the PF, as well as topography of the PF (using the sagittal suture as an anatomical landmark). RESULTS: A total of 32% of calvaria had PF present bilaterally; whilst 35% of calvaria had unilateral PF. The study also reports 5% calvaria in which PF were present on the sagittal suture. The mean diameter recorded was 1.55 mm (0.74-3.08 mm), and the mean distance between the lateral margin of the PF and the sagittal suture was 9.02 mm (4.44-18.20 mm). CONCLUSIONS: Knowledge of the incidence and topography of the PF may aid neurosurgeons in creating and adjusting techniques and procedures in order to mitigate the risk of injury to emissary veins and other structures emerging from the PF.

Do standard surgical techniques lead to satisfying aesthetic results in nonsyndromic sagittal suture synostosis?

OBJECTIVE: Surgical correction of synostotic cranial sutures is typically performed early in an affected child's life. Depending on the severity of the cranial synostoses, different aspects of the surgical treatment may have varying degrees of importance. In this sense, the aesthetic appearance in children with normal neurological development in single-suture synostosis plays an important role in self-perception and social acceptance for both the patients themselves and their caregivers. Therefore, in this study, the authors aimed to evaluate the aesthetic outcome after surgical correction in a cohort of patients with nonsyndromic sagittal suture synostosis. METHODS: Between December 2002 and December 2019, a total of 99 patients underwent surgical correction of a synostotic sagittal suture at the Medical University of Vienna. Depending on their age, patients underwent either an extended midline strip craniectomy (EMSC) (< 4 months) or a modified pi procedure (MPP) (≥ 4 months). After the surgical procedure, the outcome was evaluated by the treating neurosurgeon at 1- and 12-month follow-up visits, and after approximately 5 years, before the patient entered elementary school. In addition to that, the patients' caregivers were asked to evaluate the aesthetic outcome of the surgical procedure after 12 months. These results were then compared to evaluate potential differences in the perception of the surgical outcome. RESULTS: After 12 months, the majority of the included patients were evaluated as having a good aesthetic outcome by the treating neurosurgeon (97%) and by their caregivers (89%). These differences did not show statistical significance (p = 0.11). Similarly, no differences in the aesthetic outcome depending on the surgical procedure performed could be found (p = 0.55). At the last follow-up visit, before entering elementary school, all available patients had an excellent or good surgical outcome. Moreover, the majority of caregivers (73%) reported that their child had a normal head shape appearance after surgical correction. CONCLUSIONS: The results of this study have suggested that surgical correction of sagittal suture synostosis by simple operative techniques leads to a good aesthetic outcome and a normal head shape appearance in the majority of patients. An analysis of the evaluation of the surgical outcome by either the treating neurosurgeon or the patient caregivers showed comparable results and, thus, early intervention with simple surgical techniques can be recommended.

Hydroxyapatite Nanoparticles Facilitate Osteoblast Differentiation and Bone Formation Within Sagittal Suture During Expansion in Rats.

BACKGROUND: The potential of relapse of craniofacial disharmony after trans-sutural distraction osteogenesis is high due to the failure to produce a stable bone bridge in the suture gap. The aim of this study is to evaluate whether hydroxyapatite nanoparticles (nHAP) have the effect of promoting osteoblast differentiation of suture-derived stem cells (SuSCs) and bone formation in sagittal suture during expansion. METHODS: SuSCs were isolated from sagittal sutures and exposed to various concentrations of nHAP (0, 25, 50, and 100 µg mL-1) to determine the optimal concentration of nHAP in osteoblast differentiation via performing Western Blotting and RT-qPCR. Twenty 4-week-old male Sprague-Dawley rats were randomly assigned into 4 groups: SHAM (sham-surgery), distraction, ACS (absorbable collagen sponge) and ACS+nHAP groups. In the ACS and ACS+nHAP groups, saline solution and nHAP suspended in a saline solution were delivered by ACS placed across the sagittal suture, respectively. In the latter three groups, the suture was expanded for 14 days by 50 g of constant force via a W shape expansion device. Suture gap area, bone volume fraction (BV/TV) and bone mineral density (BMD) of sagittal sutures were assessed via micro-CT, while the mechanical properties of sagittal sutures were evaluated via nanoindentation test. The efficacy of nHAP on bone formation in sagittal suture was also evaluated via BMP-2 immunohistochemistry staining. RESULTS: The expression of osteoblast related genes and proteins induced by 25µg mL-1 nHAP were significantly higher than the other groups in vitro (p<0.05). Furthermore, treating with 25µg mL-1 nHAP in vivo, the suture gap area was significantly reduced when compared with the distraction group. Correspondingly, the BV/TV, BMD, hardness and modulus of sagittal sutures were significantly increased in the ACS+nHAP group (p<0.05). CONCLUSION: The 25µg mL-1 dose of nHAP delivered by ACS can facilitate bone formation into the sagittal suture during expansion via inducing osteoblast differentiation of SuSCs.

Acute-on-Chronic Vertex Epidural Hematoma with Diastasis of the Sagittal Suture in an Adult.

BACKGROUND: Vertex epidural hematoma (VEDH) is a rare intracranial mass constituting roughly 2.5% of all epidural hematomas. Bleeding usually derives from the superior sagittal sinus, and presentation is often acute-seldom chronic. Fractures are common, but diastasis of the sagittal suture in adults is unique. We hereby present a case combining these rare features along with diagnostic pitfalls and management. CASE DESCRIPTION: A 43-year-old male with a history of hitting his head against the roll cage of the racing car 3 weeks before admission presented with unbearable headache of 9 Numeric Rating Scale intensity and decreased muscular strength in the right upper limb down to 4/5 of the Lovett scale. The initial Glasgow Outcome Scale was 4. His axial computed tomography scan mimicked convexity hyperostosis, meningioma, or lymphoma. Coronal reconstruction revealed a 102-mL large biconcave mass of mixed hyperdensity and hypodensity at the vertex. Bone window showed sagittal suture diastasis. Contrast-enhanced magnetic resonance imaging gave evidence of superior sagittal sinus detachment. Parietofrontal craniotomy crossing the midline was performed in order to evacuate the hematoma. On 2-week follow-up his pain decreased, his right arm strength recovered, and he had a Glasgow Outcome Scale score of 5. CONCLUSIONS: VEDH can present as an intensifying headache even weeks after purported trauma. Axial computed tomography scans can be tricky because of the blind spot. Even large VEDH may be seen only in the very last few axial slices and may mimic other entities. Coronal reconstructions or additional magnetic resonance imaging come in handy. One-piece parietofrontal craniotomy is an option to approach this hematoma.

Fusion patterns of major calvarial sutures on volume-rendered CT reconstructions.

OBJECTIVE: Recently, the authors investigated the normal course of fusion of minor lateral calvarial sutures on "3D" volume-rendered head CT reconstructions in pediatric trauma patients. While evaluating these reconstructions, they found many more fused sagittal sutures than expected given the currently accepted prevalence of sagittal craniosynostosis. In the present study, using the same set of head CT reconstructions, they investigated the course of fusion of the sagittal as well as the lambdoid, coronal, and metopic sutures. METHODS: They reviewed all volume-rendered head CT reconstructions performed in the period from 2010 through mid-2012 at Children's Hospital Colorado for trauma patients aged 0-21 years. Each sagittal, lambdoid, coronal, or metopic suture was graded as open, partially fused, or fused. The cephalic index (CI) was calculated for subjects with fused and partially fused sagittal sutures. RESULTS: After exclusions, 331 scans were reviewed. Twenty-one subjects (6%) had fusion or partial fusion of the sagittal suture. Four of the 21 also had fusion of the medial lambdoid and/or coronal sutures. In the 17 subjects (5%) with sagittal suture fusion and no medial fusion of adjacent sutures, the mean CI was 77.6. None of the 21 subjects had been previously diagnosed with craniosynostosis. Other than in the 21 subjects already mentioned, no other sagittal or lambdoid sutures were fused at all. Nor were other coronal sutures fused medially. Coronal sutures were commonly fused inferiorly early during the 2nd decade of life, and fusion progressed superiorly and medially as subjects became older; none were completely fused by 18 years of age. Fusion of the metopic suture was first seen at 3 months of life; fusion was often not complete until after 2 years. CONCLUSIONS: The sagittal and lambdoid sutures do not usually begin to fuse before 18 years of age. However, more sagittal sutures are fused before age 18 than expected given the currently accepted prevalence of craniosynostosis. This finding is of unknown significance, but likely many of them do not need surgery. The coronal suture often begins to fuse inferiorly early in the 2nd decade of life but does not usually complete fusion before 18 years of age. The metopic suture often starts to fuse by 3 months of age, but it may not completely fuse until after 2 years of age.

Sagittal suture craniosynostosis or craniosynostoses? The heterogeneity of the most common premature fusion of the cranial sutures.

BACKGROUND: Scaphocephaly is usually defined as the deformation of the skull resulting from the premature fusion of the sagittal suture. It is the most common type of craniosynostosis, and can be easily recognized on simple clinical examination. Its pathophysiology is easy to understand and to confirm on neuroradiological examination. In contrast, surgical indications are still somewhat controversial, the dispute mainly concerning therapeutic versus esthetic objectives. In recent years, however, several studies have challenged these basic and relatively simplistic interpretations of the pathophysiology of the condition. MATERIALS AND METHODS: To assess the heterogeneity of scaphocephaly, we reviewed cases of scaphocephaly operated on at the Hôpital Femme-Mère-Enfant, Lyon University Hospital, France during a 10-year period (2008-2017) and performed a review of the literature on scaphocephaly and sagittal suture closure. RESULTS: During the 10-year period, 401 children were operated on for a scaphocephaly at the Hôpital Femme Mère Enfant, Lyon University Hospital. Mean age at surgery was 1.14 years, for a median 0.7 years (range, 4 months to 8. 5 years). Several subtypes could be distinguished according to morphology, intracranial findings on imaging, patient age, and etiology associated to the sagittal synostosis. Two main surgical techniques were used to correct the malformation, depending on patient age, type of deformation and the surgeon's preference: cranial vault remodeling with occipital pole widening, with the patient in a prone position, and parietal enlargement with or without forehead remodeling, in dorsal decubitus. CONCLUSIONS: The complexity and heterogeneous nature of sagittal synostoses depend on different pathogenic mechanisms leading to and interfering with the skull abnormalities: abnormalities of CSF dynamics, possibly associated with systemic alterations, accounting for the varied postoperative morphological and functional course, in terms of cognitive impairment and late complications (notably intra-cranial pressure elevation). However, the real impact of such heterogeneous clinical presentations on surgical indications and surgical results remains to be elucidated.