Reassessing the association: Evaluation of a polyalanine deletion variant of RUNX2 in non-syndromic sagittal and metopic craniosynostosis.

The RUNT-related transcription factor RUNX2 plays a critical role in osteoblast differentiation, and alterations to gene dosage cause distinct craniofacial anomalies. Uniquely amongst the RUNT-related family, vertebrate RUNX2 encodes a polyglutamine/polyalanine repeat (Gln23-Glu-Ala17 in humans), with the length of the polyalanine component completely conserved in great apes. Surprisingly, a frequent 6-amino acid deletion polymorphism, p.(Ala84_Ala89)del, occurs in humans (termed 11A allele), and a previous association study (Cuellar et al. Bone 137:115395;2020) reported that the 11A variant was significantly more frequent in non-syndromic sagittal craniosynostosis (nsSag; allele frequency [AF] = 0.156; 95% confidence interval [CI] 0.126-0.189) compared to non-syndromic metopic craniosynostosis (nsMet; AF = 0.068; 95% CI 0.045-0.098). However, the gnomAD v.2.1.1 control population used by Cuellar et al. did not display Hardy-Weinberg equilibrium, hampering interpretation. To re-examine this association, we genotyped the RUNX2 11A polymorphism in 225 individuals with sporadic nsSag as parent-child trios and 164 singletons with sporadic nsMet, restricting our analysis to individuals of European ancestry. We compared observed allele frequencies to the non-transmitted alleles in the parent-child trios, and to the genome sequencing data from gnomAD v.4, which display Hardy-Weinberg equilibrium. Observed AFs (and 95% CI) were 0.076 (0.053-0.104) in nsSag and 0.082 (0.055-0.118) in nsMet, compared with 0.062 (0.042-0.089) in non-transmitted parental alleles and 0.065 (0.063-0.067) in gnomAD v.4.0.0 non-Finnish European control genomes. In summary, we observed a non-significant excess, compared to gnomAD data, of 11A alleles in both nsSag (relative risk 1.18, 95% CI 0.83-1.67) and nsMet (relative risk 1.29, 95% CI 0.87-1.92), but we did not replicate the much higher excess of RUNX2 11A alleles in nsSag previously reported (p = 0.0001).

Brain volume in infants with metopic synostosis: Less white matter volume with an accelerated growth pattern in early life.

Metopic synostosis patients are at risk for neurodevelopmental disorders despite a negligible risk of intracranial hypertension. To gain insight into the underlying pathophysiology of metopic synostosis and associated neurodevelopmental disorders, we aimed to investigate brain volumes of non-syndromic metopic synostosis patients using preoperative MRI brain scans. MRI brain scans were processed with HyperDenseNet to calculate total intracranial volume (TIV), total brain volume (TBV), total grey matter volume (TGMV), total white matter volume (TWMV) and total cerebrospinal fluid volume (TCBFV). We compared global brain volumes of patients with controls corrected for age and sex using linear regression. Lobe-specific grey matter volumes were assessed in secondary analyses. We included 45 metopic synostosis patients and 14 controls (median age at MRI 0.56 years [IQR 0.36] and 1.1 years [IQR 0.47], respectively). We found no significant differences in TIV, TBV, TGMV or TCBFV in patients compared to controls. TWMV was significantly smaller in patients (-62,233 mm3 [95% CI = -96,968; -27,498], Holm-corrected p = 0.004), and raw data show an accelerated growth pattern of white matter in metopic synostosis patients. Grey matter volume analyses per lobe indicated increased cingulate (1378 mm3 [95% CI = 402; 2355]) and temporal grey matter (4747 [95% CI = 178; 9317]) volumes in patients compared to controls. To conclude, we found smaller TWMV with an accelerated white matter growth pattern in metopic synostosis patients, similar to white matter growth patterns seen in autism. TIV, TBV, TGMV and TCBFV were comparable in patients and controls. Secondary analyses suggest larger cingulate and temporal lobe volumes. These findings suggest a generalized intrinsic brain anomaly in the pathophysiology of neurodevelopmental disorders associated with metopic synostosis.

Dura-based automated vault expansion remodelling (DAVE-R): automated planning of volume expansion in fronto-orbital advancement for trigonocephaly.

Cranial vault remodelling for craniosynostosis aims to increase intracranial volume to facilitate brain growth, avoid the development of raised intracranial pressure and address cosmesis. The extent of vault expansion is predominantly limited by scalp closure and reconstruction technique. Virtual surgical planning tools have been developed to predict post-operative changes and guide expansion. We present a validation study of a novel 'Dura-based Automated Vault Expansion-Remodeling' (DAVE-R) model to guide pre-operative planning for fronto-orbital advancement and remodelling (FOAR). METHODS: Patients with trigonocephaly who underwent FOAR with pre- and post-operative imaging from 2018 to 2020 were identified from a prospectively maintained database. Post-operative scans, normative atlas and whole brain parcellation were registered to the pre-operative images to quantify the change in intracranial volume and morphology (utilising measurement of fronto-orbital advancement and bifrontozygomatic distance) compared to that predicted by the DAVE-R model. RESULTS: Ten patients were included. The DAVE-R model predicted bifrontozygomatic distances of 92.0 + / - 5.14 mm (mean + /SD), which closely matched the post-operative results of 92.7 + / - 6.02 mm (mean + / - SD); (t(d.f. 9) = -0.306, p = 0.77). The fronto-orbital advancement predicted by the DAVE-R method was 11.5 + / - 1.96 mm (mean + / - SD) which was significantly greater than 8.6 + / - 2.94 mm (mean ± SD); (t(d.f. 9) = 3.137, p = 0.01) achieved post-operatively. CONCLUSIONS: We demonstrate that the DAVE-R model provides an objective means of extracting realistic surgical goals in patients undergoing FOAR for trigonocephaly that closely correlates with post-operative outcomes. The normative dural model warrants further study and validation for other forms of craniosynostosis correction.

Surgical strategy in treatment of metopic synostosis in a single centre experience: technical note and quantitative analysis of the outcomes.

PURPOSE: Trigonocephaly is the most common craniosynostosis involving orbits. Although some degree of agreement has been reached regarding surgical timing and indications for treatment, there is no consensus regarding the ideal operative technique to guarantee an optimal morphological outcome. The purpose of this study is to describe both strategies and to compare morphological outcomes by means of morphological surface analysis obtained from three-dimensional (3D) stereophotogrammetry, with two different techniques. METHODS: We retrospectively investigated 43 patients with metopic synostosis surgically treated between 2004 and 2020. Two different techniques were applied, addressed as technique A and B. Ten patients undergone postoperative 3d stereophotogrammetry were enrolled, and cephalometric measurements were taken and compared to a cohort of unaffected patients matched by age and gender. RESULTS: Comparison of the groups demonstrated a hypercorrection of the metopic angle of the second technique, associated with a slightly lower correction of the interfrontoparietal diameter. The metopic angle showed to be significantly undercorrected with the first method. CONCLUSIONS: Alternated barrel staving technique appears to be a quick and satisfactory method in cranial remodelling for metopic synostosis. It guarantees an optimal aesthetic result in the first years after surgery.

Secondary metopic craniosynostosis after posterior cranial decompression in cloverleaf skull deformity.

Cloverleaf skull deformity or Kleeblattschadel syndrome is a severe condition where multiple cranial sutures are absent and prematurely fused, leading to a trilobate head shape. The remaining open sutures or fontanelles compensate for rapid brain expansion, while the constricted fused calvarium restricts brain growth and results in increased intracranial pressure. Recent data show that early posterior cranial and foramen magnum decompression positively affects infants with cloverleaf skulls. However, long-term sequelae are still rarely discussed. We hereby report a child who developed secondary metopic craniosynostosis after posterior cranial decompression, which required a front-orbital advancement and cranial remodelling as a definitive procedure.

A Three-Dimensional-Based Morphometric Analysis of a Standardized Overcorrection Technique for Fronto-Orbital Advancement in Metopic Craniosynostosis.

INTRODUCTION: The concept of "overcorrection" for trigonocephaly has been reported to achieve both anterior cranial fossa expansion and normalization of craniofacial form. The purpose of this study is to describe in detail a standardized technique to fronto-orbital advancement utilizing the concept of "overcorrection" and objectively evaluate intermediate results. METHODS: This retrospective study included patients with isolated metopic synostosis who underwent surgery via the proposed surgical technique and age and sex-matched unaffected controls. Craniofacial morphometric analysis was performed on pre-, immediate post-, and intermediate postoperative (>2 years) three-dimensional (3D)-rendered computed tomographic (CT) scans and photographs. Key CT-based measurements included interzygomaticofrontal suture distance (IZFS), endocranial bifrontal angle (ECA), and temporal expansion. 3D photogrammetry was performed using established measurements and associated Z-scores converted. A Paired t-test and analysis of variance were performed when appropriate. RESULTS: Forty-one patients were included. A comparison of pre- and immediate postoperative CT scans demonstrated statistically significant increases in all measurements. Subset analysis of 12 patients with intermediate follow-up (age: 39.6 ± 3.6 months) demonstrated significant differences from preoperative values except for IZFS, which decreased from immediate postoperative values and was smaller than age- and sex-matched controls. 3D photogrammetry demonstrated a mean Z-score above the norm for frontal breath. 3D photogrammetry is also positively correlated with CT-based measurements. CONCLUSIONS: This standardized "overcorrection" approach for trigonocephaly can provide the appropriate changes to maintain a normal ECA despite a reduction in bifrontal width over time. 3D photogrammetry positively correlated with CT-based measurements and may provide useful information when following patients clinically. Long-term follow-up assessment to determine the necessary degree of overcorrection at skeletal mature is needed.

Quantitative outcomes of endoscopic strip craniectomy for metopic craniosynostosis in children with severe trigonocephaly.

PURPOSE: To assess intermediate-term (> 3 years) outcomes of endoscopic strip craniectomy with postoperative helmet therapy (ESC + HT) for the treatment of infants with severe trigonocephaly. METHODS: This retrospective study examined cranial morphology of consecutive patients with severe trigonocephaly treated with minimally invasive ESC + HT. Preoperative and follow-up clinical parameters were collected from patient charts. Interfrontal divergence angle (IFDA), a validated and accurate measure of forehead narrowing, was measured on preoperative CT scans and on preoperative and postoperative 2D photographs. RESULTS: Seven patients (4 male, 3 female) were included with a mean age at surgery of 2.76 months (range 1.8 to 4.1 months) and mean clinical follow-up of 3.71 years (photographic follow-up 2.73 years). The mean operative time was 91.4 min, with a mean estimated blood loss (EBL) of 57.1 ml and mean hospital length of stay of 1.14 days. IFDA improved from 118.8° to 135.9° (p < 0.01), with the mean final measurement falling within normal limits. The head circumference percentile was not significantly changed in follow-up. There was a statistically significant improvement in the inner-to-outer canthal distance ratio (p = 0.01) in follow-up, showing an improvement in hypotelorism. There were no dural tears, CSF leaks, infections, or other significant surgical morbidities, and there were no serious complications related to the use of helmet therapy. All patients achieved excellent aesthetic results judged by photographic comparison. CONCLUSION: This study demonstrated that patients treated with ESC + HT for metopic craniosynostosis showed measurable and significant improvement in forehead shape. This technique is a safe and effective alternative to more invasive surgical interventions.

Emissary veins and pericerebral cerebrospinal fluid in trigonocephaly: do they define a specific subtype?

INTRODUCTION: The premature fusion of the metopic suture may be associated with the presence of emissary veins (EV) and abnormally large pericerebral cerebrospinal fluid (CSF) spaces which suggest an associated focal disturbance in CSF dynamics. The incidence of such findings and their potential significance in terms of management of the disease have not been fully elucidated. The aim of this study is to investigate whether these phenomena identify specific subtypes of trigonocephaly. In such a direction, we evaluated the volume of the pericerebral CSF spaces and their relationship to the morphology ("Ω," "V," or flat type) of the prematurely fused metopic suture and to the value of the interfrontal angle value on the grounds of computed tomographic (CT) scan examinations. METHOD: The preoperative brain CT scans of 74 children (52 boys, 22 girls) with trigonocephaly who had undergone fronto-orbital remodeling were evaluated. The volume of the pericerebral CSF spaces and the value of the interfrontal angle were calculated. The type of intracranial notch was studied and classified according to its shape on the preoperative CT scan: a groove "Ω," a ridge/"V" ridge or absent when flat and evidence of emissary veins related to the abnormally fused suture. RESULTS: Preoperatively, an endocranial metopic groove or ridge was seen in 70% of the children. Emissary veins were identified in 34 of 74 patients (45%), at a mean distance of 2.04 cm (1.18-2.94 cm) from the nasion. The presence of large pericerebral CSF spaces significantly correlated with the presence of EV (p < 0.05), with the "Ω" type (p < 0.05) and with interfrontal angles under 134° (p < 0.005). CONCLUSIONS: Metopic suture early fusion shows an association between EV, pericerebral CSF spaces, and the "Ω" groove appearance of the suture. This association identifies a specific subgroup in which the presence of emissary veins and large pericerebral CSF spaces is an indicator of local venous hypertension due to the sagittal sinus constriction within an osseous groove created by the abnormal suture fusion process. The implications for the surgical management and long-term results as compared to trigonocephalic children with small or absent normal peripheral spaces and EV are still to be determined.

Evaluation of fronto-orbital reconstruction surgery for the treatment of metopic synostosis in Chinese population.

PURPOSE: To evaluate the efficacy of fronto-orbit reconstruction surgery on pediatric metopic synostosis via an image-based 3D reconstruction in Chinese population. METHODS: Thirty pediatric metopic synostosis patients who received fronto-orbital reconstruction surgery in the Children's Hospital of Nanjing Medical University, Department of Neurosurgery, from January 2007 to December 2018 were analyzed in the study. Here we use the Mimics 20.0 software to reconstruct patients' cranial thin-section CT scan images from pre- and post-operation and control groups. Then the data of intracranial volume, frontal volume, orbital hypertelorism, ECA, ZF, and ORA were analyzed using the paired t-test or Wilcoxon matched-pairs signed-ranks test. RESULTS: The age of these patients was 15.83 ± 16.12 months. After surgery, the mean frontal volume was enlarged from 92.75 ± 26.97 to 138.62 ± 47.97 cm3 (P < 0.0001), and the intracranial volume was enhanced from 976.87 ± 230.83 to 1059.44 ± 217.98 cm3 (P < 0.0001). In the meantime, the ECA was changed from 108.02 ± 8.17 to 134 ± 5.59° (P < 0.0001). In line with the alteration of the parameters mentioned above, the head shapes in all patients were also significantly improved after the surgery with no obvious complications. CONCLUSION: Fronto-orbit reconstruction surgery is a safe and effective treatment for pediatric metopic synostosis. Computer-aided 3D reconstruction could serve as a quantitative strategy to evaluate the efficacy of craniofacial surgery.

Bibliometric analysis of the top 100 most cited articles on craniosynostosis.

BACKGROUND: Craniosynostosis is the premature closure of cranial sutures and it continues to be a therapeutic challenge due to the diversity and complexity of the syndrome. Bibliometric analysis is a study of ranking citations and exploring the most impactful articles in a respective discipline. It also demonstrates the chronological trends of publications. METHODS: In May 2020, we performed a title-specific search of the Scopus database using "craniosynostosis" as our query term without publication date restrictions. The top 100 articles in craniosynostosis were retrieved and analyzed. RESULTS: The top 100 most-cited articles in craniosynostosis received a total 13,826 citations, and an average of 138 citations per paper. The publication dates ranged from 1920 to 2015, with a peak period of top publications between 1996 and 2005. The most common category is clinical, followed by neurogenetics. The top cited article received 540 citation counts and 19.29 citations per year. The USA was the most contributing country to the list. The Journal of Plastic and Reconstructive Surgery published the largest number of top cited articles. Neurosurgery as a specialty contributed to most articles in the list (27 articles). The institute who contributed the most was the Assistance Publique Hopitaux Paris. CONCLUSION: Bibliometric analysis in craniosynostosis revealed major trend changes of research over the years, with a focus on neurogenetics and the different types of surgical corrections. The current collection of highly cited publications may assist physicians in gaining a better understanding of the evidence-based approach in craniosynostosis.

Postsurgical Size-Changing Temporal Lobe Arachnoid Cysts in Patients with Trigonocephaly Who Underwent Reconstructive Surgery: A Two-Case Report.

INTRODUCTION: Trigonocephaly (TC), the tapering of the metopic suture toward the anterior, lateral inadequacy of supraorbital bar, hypoplasia of the ethmoid bone, and hypotelorism due to orbital medialization leads to a triangular shape in the head together with frontotemporal stenosis and widening of the biparietal diameter. Arachnoid cysts (ACs) are benign cysts, which are formed by cerebrospinal-fluid entrapment into the arachnoid membrane due to duplication or separation of the arachnoid membrane layers. ACs are typically located in the middle cranial fossa and Sylvian fissure region. They are mostly detected incidentally through neuroimaging. The coexistence of TC and AC is considerably rare; hence, its actual incidence is unknown. To our knowledge, the coexistence of nonsyndromic TC and AC has been revealed in only 2 publications in the literature. In this case study, 2 patients, one of whom were with unilateral and the other with bilateral temporally localized ACs, sizes of which increased following the reconstructive surgeries, and who underwent reconstructive surgery for TC, were presented. CASE REPORT: Both of the 2 patients that we have presented in our study are 7 months old and male. Fronto-orbital advancement and calvarial remodeling operations were performed on both. ACs of the patients were not intervened. However, in the post-op follow-ups, the left temporal cyst of the 1st case and the right cyst of the 2nd case grew radiologically, and the left cyst became very small. DISCUSSION/CONCLUSION: TC must be treated surgically. ACs may show changes in size secondary to the increase in intracranial volume following reconstructive surgery for TC. However, if it does not give rise to any complaints, it can be followed-up clinically and radiologically. Patients should be followed-up for many years, given that neurodevelopmental and behavioral problems may occur later in both pathologies.

SMAD6 variants in craniosynostosis: genotype and phenotype evaluation.

PURPOSE: Enrichment of heterozygous missense and truncating SMAD6 variants was previously reported in nonsyndromic sagittal and metopic synostosis, and interaction of SMAD6 variants with a common polymorphism nearBMP2 (rs1884302) was proposed to contribute to inconsistent penetrance. We determined the occurrence of SMAD6 variants in all types of craniosynostosis, evaluated the impact of different missense variants on SMAD6 function, and tested independently whether rs1884302 genotype significantly modifies the phenotype. METHODS: We performed resequencing of SMAD6 in 795 unsolved patients with any type of craniosynostosis and genotyped rs1884302 in SMAD6-positive individuals and relatives. We examined the inhibitory activity and stability of SMAD6 missense variants. RESULTS: We found 18 (2.3%) different rare damaging SMAD6 variants, with the highest prevalence in metopic synostosis (5.8%) and an 18.3-fold enrichment of loss-of-function variants comparedwith gnomAD data (P < 10-7). Combined with eight additional variants, ≥20/26 were transmitted from an unaffected parent but rs1884302 genotype did not predict phenotype. CONCLUSION: Pathogenic SMAD6 variants substantially increase the risk of both nonsyndromic and syndromic presentations of craniosynostosis, especially metopic synostosis. Functional analysis is important to evaluate missense variants. Genotyping of rs1884302 is not clinically useful. Mechanisms to explain the remarkable diversity of phenotypes associated with SMAD6 variants remain obscure.

Physiologic closure time of the metopic suture in South Australian infants from 3D CT scans.

Metopic synostosis is a craniofacial condition characterised by the premature fusion of the metopic suture. This early fusion restricts frontal bone growth [17] and has significant impacts on the developing infant during a critical phase of rapid growth and development [4]. Diagnosis of the condition is usually achieved by clinical assessment, followed by a three-dimensional computed tomography (3D CT) scan, verifying premature metopic suture fusion. PURPOSE: This retrospective study aims to investigate the timing of metopic suture fusion in the developing infant in an Australian subpopulation. METHODS: The study evaluates metopic suture fusion in 258 cranial 3D CT scans of children aged 0-24 months over a 5-year period (2011-2016), scanned at Women's and Children's Hospital. RESULTS: The findings suggest that the age range over which physiologic metopic suture fusion occurs is larger than previously reported. CONCLUSIONS: The approximate range for physiologic fusion was found to be 3-19 months and patients with fusion within this range can be considered normal. Complete suture fusion is expected by 19 months. Additionally, results indicate suture fusion prior to 3 months is abnormal and diagnostically indicative of metopic synostosis.

Control of metopic emissary veins in trigonocephaly surgery. Technical note.

INTRODUCTION: Trigonocephaly with its premature fusion of the metopic synostosis is associated with a risk of cerebral compression and several craniofacial morphological deformations. Numerous surgical techniques have been proposed to enlarge and reshape the forehead. They all carry a risk of bleeding during osteotomies, especially in the region of the superior sagittal sinus (SSS) encased in the early fused suture and of the paired metopic transosseous emissary veins superior to the glabella, which is typical of this type of synostosis. In fact, these paired metopic transosseous veins are often, if not always, the source of major bleeding when torn during the elevation of the frontal flap. TECHNICAL NOTE: A simple technical variant may prevent or at least easily control bleeding in this region during the early phases of the surgical repair. The technical variant to the standard surgical techniques utilized to correct trigonocephaly consists in preserving a triangle of bone above the glabella (about 4 cm at the base and 4 cm in height). The triangle of bone contains the initial segment of the SSS and the emissary metopic veins draining the frontal poles. After removing the frontal flap in a conventional manner, this technical variant allows to detach the veins as well as the SSS from the surrounding bone structures under direct visualization, also in case of vessels running partially encased in the bone. Once the venous structure is detached and hemostasis controlled, this last piece of frontal bone may be removed without unnecessary "iatrogenic" bleeding. CONCLUSION: The propounded procedure does not prolong the surgical time significantly and does not require additional surgical skills or equipment.

Non-syndromic single-suture craniosynostosis in triplets.

INTRODUCTION: Craniosynostosis is the premature fusion of one or more cranial sutures. The cause of non-syndromic craniosynostosis has been attributed to a complex interaction among genetic, epigenetic, and environmental factors. Increased concordance rates in monozygotic twins support a genetic etiology while a concordance rate less than 100% suggests environmental and/or epigenetic influences. Here, we describe the first reported occurrence of all three children in a triplet set with non-syndromic single-suture craniosynostosis. CASE REPORT: The dichorionic triamniotic triplets were the product of a non-consanguineous marriage delivered at 35 weeks' gestation by a 38-year-old mother and consisted of a monochorionic-diamniotic pair (A and B) and a fraternal triplet (C). Three-dimensional computed tomography scans confirmed sagittal synostosis in A and B and metopic synostosis in C. All patients underwent endoscopic strip craniectomy and were discharged on the second postoperative day with helmet orthoses. Comparative genetic hybridization (CGH) and whole-exome sequencing (WES) failed to identify pathogenic copy number variants or gene mutations, respectively. DISCUSSION AND CONCLUSION: The results of the genetic testing suggest the possibility of a rare variant contributing to the risk of midline craniosynostosis shared among the triplets, with potential modifiers at other genetic loci affecting the phenotype. We speculate mutations at loci within non-coding regions not captured by our genetic analysis may have been involved. Moreover, epigenetic factors as well as environmental factors including, but not limited to, in utero head constraint could have contributed to the observed phenotype.

[Non syndromic craniosynostosis]. / Les craniosténoses non syndromiques.

Craniosynostosis are rare congenital malformations of the skull resulting from the premature fusion of one or several cranial sutures. Prevalence is considered in approximately 1 on 2000 births. Non syndromic craniosynostosis (NSC) or isolated form are the most frequent forms (85 % of the cases). They are classified most of the time according to the synostotic suture(s) and the engendered cranial deformation: sagittal synostosis or scaphocephaly, metopic synostosis or trigonocephaly, bicoronal synostosis or brachycephaly, coronal synostosis or plagiocephaly and oxycephaly. Although the multifactorial origin is commonly admitted, the precise mechanisms which lead to the premature fusion of a suture, remain incompletely resolute. The main risks are the intracranial high blood pressure and its consequences on the psychomotor development, the visual or respiratory infringement which can require a surgery in emergency. The treatment is realized by multidisciplinary teams allowing to provide a strategy adapted to every situation. The decision-making process depends on patient's age, on the type and severity of the craniosynostosis, and on the patient's health. This surgery is ideally performed before the age of 1 year and indication only in morphological purpose is widely recognized to avoid any social damage to the child. The follow-up is essential and is made throughout the growth in particular to detect a recurrence or the evolution towards a complex form of craniosynostosis.

The cranial orbital buttress technique for nonsyndromic unicoronal and metopic craniosynostosis.

OBJECT Current craniosynostosis procedures can result in complications due to absorbable plates and screws or other specialized expensive hardware. The authors propose the cranial orbital buttress (COB) technique of frontoorbital remodeling for metopic and unicoronal synostoses, wherein no plates or screws are used. They hypothesize that, with this technique, aesthetically acceptable outcomes for unicoronal and metopic synostosis can be achieved. In this article, they present this technique and compare the results with current frontoorbital remodeling practices. METHODS The authors conducted a retrospective chart review of cases in which patients with nonsyndromic unicoronal or metopic synostosis underwent cranio-orbital surgery at their institution from 1985 through 2009. Operative parameters, surgical variations, and complications were analyzed. The COB technique uses a 1-piece switch, hemiforeheads, or multiple pieces for forehead remodeling. The supraorbital bar is reconstructed in patients with metopic synostosis using a double wedge or greenstick fracture technique, and in patients with unicoronal synostosis a hinge procedure based on a 1.5-orbital osteotomy is used. The supraorbital bar is advanced and supported in place by bone graft(s) inserted at the lateral aspect(s) of the orbit(s) to form a buttress, with fixation done using absorbable sutures. RESULTS A total of 79 cases met the criteria for inclusion in the study. Twenty-nine patients had metopic synostosis, 3 had combined metopic and sagittal synostoses, and 47 had unicoronal synostosis. The patients' mean age at surgery was 11.4 ± 10.1 months and the mean operative time was 183.4 ± 41.0 minutes. The mean length of hospital stay was 3.7 ± 1.2 days. The mean blood loss was 150.0 ± 125.6 ml, and 33% of patients required a blood transfusion (mean volume 206.9 ± 102.3 ml). In metopic synostosis, hemiforeheads were used most often (24/29, 83%), and the supraorbital bar was remodeled using a bilateral intracranial orbital osteotomy followed by a double wedge modification (23/29, 79%) or a greenstick fracture (4/29 14%) for milder cases. Forehead remodeling for unicoronal synostosis was by a forehead switch (39/47, 83%) and the supraorbital bar was remodeled using a 1.5-orbital intracranial orbital osteotomy (34/47, 72%) such that the bar was advanced on the abnormal side and hinged at the midline of the normal orbit. Perioperative complications occurred in 19% of cases and included dural tears (16%), inconsequential subdural hematoma (1.3%), and nasal greenstick fracture (1.3%). The total reoperation rate was 7.6% (cranioplasties for irregular contours, 6.3%; scar revision, 1.3%). CONCLUSIONS The COB remodeling technique is simple and efficient, gives acceptable outcomes, and is less resource intensive than previous techniques reported in the literature.

Trigonocephaly: Quantitative Comparison of the Complete Vault Reconstruction and Minimally Invasive Suturectomy.

OBJECTIVE: The objective of the study was to present and compare outcomes and complications of conventional open reconstruction and minimally invasive correction of metopic synostosis in patients who underwent treatment of trigonocephaly in our center between 2015 and 2019. METHODS: The hospital database was searched for hospitalization and surgical information, as well as imaging of individuals with trigonocephaly. Postoperative evaluation of the patients was performed during the follow-up sessions. The radiological evaluation was based on brain computed tomography scans taken 2 years following the operation. RESULTS: Sixty-four patients (19 females and 45 males) had their trigonocephaly corrected surgically. Thirty-five patients (9 females and 26 males) had complete vault reconstruction surgery, while 29 patients (10 females and 19 males) had minimally invasive suturectomy (MIS). The postoperative cephalic width/intercoronal distance ratio and interpupillary distance/interfrontozygomatic distance ratio assessment showed no differences in the outcome of both groups (P value > 0.05). Minimally invasive techniques resulted in less intraoperative bleeding, a shorter stay in the intensive care unit and hospital, and a shorter surgery and anesthesia duration (P value < 0.05). CONCLUSIONS: Surgical treatment of trigonocephaly can result in a satisfactory correction of the deformity. MIS delivers a comparable result to complete vault reconstruction with less invasiveness and hospitalization and can be considered a reasonable option for patients in their early months of life. Patients must, however, undergo long-term cosmetic, behavioral, and developmental evaluations.

Correction of trigonocephaly after endoscopic strip craniectomy with postoperative helmet orthosis therapy: a 3D stereophotogrammetric study.

OBJECTIVE: Endoscopic strip craniectomy with postoperative helmet orthosis therapy (ESCH) has emerged as a less invasive alternative to fronto-orbital remodeling for correction of trigonocephaly. However, there is no standardized objective method for monitoring morphological changes following ESCH. Such a method should be reproducible and avoid the use of ionizing radiation and general anesthesia for diagnostic imaging. The authors analyzed a number of metrics measured using 3D stereophotogrammetry (3DSPG) following ESCH, an imaging alternative that is free of ionizing radiation and can be performed on awake children. METHODS: 3DSPG images obtained at two time points (perisurgical and 1-year follow-up [FU]) of children with metopic synostosis who had undergone ESCH were analyzed and compared to 3DSPG images of age-matched control children without craniofacial anomalies. In total, 9 parameters were measured, the frontal angle and anteroposterior volume in addition to 7 novel parameters: anteroposterior area ratio, anteroposterior width ratios 1 and 2, and right and left anteroposterior diagonal ratios 30 and 60. RESULTS: Six eligible patients were identified in the operated group, and 15 children were in the control group. All 9 parameters differed significantly between perisurgical and age-matched controls, as well as from perisurgical to FU scans. Comparison of FU scans of metopic synostosis patients who underwent surgery to scans of age-matched controls without metopic synostosis revealed that all parameters were statistically identical, with the exception of the right anteroposterior diagonal ratio 30, which was not fully corrected in the treated patients. The left anterior part of the head showed the most change in surface area maps. CONCLUSIONS: In this pilot study, ESCH showed satisfactory results at 1 year, with improvements in all measured parameters compared to perisurgical results and normalization of 8 of 9 parameters compared to an age-matched control group. The results indicate that these parameters may be useful for craniofacial units for monitoring changes in head shape after ESCH for trigonocephaly and that 3DSPG, which avoids the use of anesthesia and ionizing radiation, is a satisfactory monitoring method.

Fronto-Orbital Advancement for Metopic and Unilateral Coronal Craniosynostoses.

Fronto-orbital advancement remains a powerful technique for the correction of anterior cranial vault differences related to metopic (trigonocephaly) or unilateral coronal (anterior plagiocephaly) craniosynostoses. Traditional fronto-orbital advancement requires access to the forehead and superior 2/3 of the orbit via a coronal incision. The frontal bone and orbital segment (bandeau) are then separated from the skull and reshaped. In patients with metopic craniosynostosis, the bandeau and frontal bone will need to be advanced and widened. In patients with unilateral coronal craniosynostosis, the bandeau will need to be "untwisted" to address the supraorbital retrusion on the affected side, the affected orbit will need to be shortened and widened, and the frontal bone flap will need to be proportionately advanced on the affected side. Overcorrection of the affected dimension should be undertaken to account for growth and relapse.