Surgical Correction of Nonsyndromic Sagittal Craniosynostosis: Concepts and Controversies

Nonsyndromic Craniofacial Disorders

We describe the investigation and management of select pediatric craniofacial disorders their recent advances. Positional plagiocephaly: The incidence of positional plagiocephaly has increased since the institution of the "safe to sleep" campaign to reduce sudden infant death syndrome. Positional plagiocephaly may be associated with underlying developmental delay. Nonsyndromic craniosynostosis: Treatment of nonsyndromic craniosynostosis depends on the age of the patient and the suture involved. Pediatric skull lesions: Management of skull lesions depends on histologic diagnosis. Some benign skull lesions are managed conservatively, whereas erosive and malignant lesions may require surgical excision, radiotherapy, chemotherapy, or multimodality treatment.

Sagittal Synostectomy With Tension Band Sutures for Correction of Sagittal Craniosynostosis

BACKGROUND AND OBJECTIVES

Premature fusion of the sagittal suture is the most common form of craniosynostosis and can be treated using a variety of open or endoscopic approaches. Existing approaches have varying degrees of effectiveness. Open approaches, whether performed early or late, can be associated with significant blood loss and the need for transfusion. Endoscope-assisted approaches are minimally invasive but require months of postoperative helmet therapy to help remodel the skull. Implantation of springs or distractors requires a second operation for removal of the devices. Here, we present an alternative technique for early correction of sagittal craniosynostosis combining sagittal synostectomy with tension band sutures to remodel the skull without need for transfusion or helmet therapy.

METHODS

We retrospectively reviewed the medical records of all patients treated for sagittal craniosynostosis using a synostectomy with tension band sutures at a single tertiary care institution. Data on patient demographics, operative factors, and postoperative course were collected.

RESULTS

Thirty-four patients underwent the novel procedure. The median preoperative cephalic index was 68 and improved to 76 immediately postoperatively. The median blood loss was 10 mL while the operative duration was 112 minutes. No blood transfusions were needed. One small dural laceration was encountered that was promptly repaired. There were no postoperative complications. Patients presenting for follow-up visits showed continued improvement in head shape and cephalic index.

CONCLUSION

A modified sagittal craniectomy with tension band sutures to remodel the skull is effective in achieving immediate correction of sagittal craniosynostosis. The correction remains durable over long-term follow-up. Importantly, the technique can be performed with minimal blood loss and reduces transfusion risk, operative time, and overall morbidity compared with traditional open approaches while avoiding the need for helmet therapy necessitated by endoscopic approaches.

Long-term neurocognitive outcomes in 204 single-suture craniosynostosis patients

PURPOSE

Craniosynostosis, which describes premature fusion of one or more cranial sutures, has been associated with a variety of neurocognitive deficits. We sought to explore the cognitive profiles of the various types of single-suture, non-syndromic craniosynostosis (NSC).

METHODS

A retrospective review of children 6-18 years old with surgically corrected NSC who underwent neurocognitive testing (Weschler Abbreviated Scale of Intelligence, Beery-Buktenica Developmental Test of Visuomotor Integration) from the years 2014-2022 was conducted.

RESULTS

204 patients completed neurocognitive testing (139 sagittal, 39 metopic, 22 unicoronal, 4 lambdoid suture). 110 (54%) of the cohort was male, and 150 (74%) were White. Mean IQ was 106.10±14.01 and mean age at surgery and testing were 9.0±12.2 months and 10.9±4.0 years, respectively. Sagittal synostosis was associated with higher scores than metopic synostosis, with significant differences in verbal IQ (109.42±15.76 vs 101.37±10.41), full-scale IQ (108.32±14.44 vs 100.05±11.76), visuomotor integration (101.62±13.64 vs 92.44±12.07), visual perception (103.81±12.42 vs 95.87±11.23), and motor coordination (90.45±15.60 vs 84.21±15.44). Sagittal synostosis was associated with significantly higher scores for visuomotor integration (101.62±13.64 vs 94.95±10.24) and visual perception (103.81±12.42 vs 94.82±12.75) than unicoronal synostosis.

CONCLUSIONS

Compared to patients with sagittal synostosis, patients with metopic synostosis exhibited lower scores in verbal IQ, full-scale IQ, visuomotor integration, visual perception, and motor control after surgical correction. Despite surgical correction for premature metopic suture fusion, the effect on the adjacent frontal lobe and white matter connections to other regions of the brain may have a lasting functional impact. Patients with unicoronal synostosis exhibited lower visuomotor integration and visual perception scores.

An Esthetic Scoring System for Scaphocephaly Assessment and Outcomes: A Pilot Study

Scaphocephaly is the commonest form of craniosynostosis with a varied presentation consisting of many morphological components and a range of possible surgical interventions. However, with regard to esthetic assessment, there is no universally applied assessment system. The aim was to develop a simple assessment tool encompassing multiple phenotypic components of scaphocephaly. This was done by piloting a red/amber/green (RAG) scoring system to judge esthetic outcomes following scaphocephaly surgery using photographs and experienced observers. Standard photographic views of 20 patients who had undergone either passive or anterior 2/3 vault remodelling were scored by 5 experienced assessors. Using a RAG scoring system before and after scaphocephaly correction according to 6 morphological characteristics: visual impression of cephalic index, calvarial height, bitemporal pinching, frontal bossing, posterior bullet, and displacement of the vertex. All 5 assessors were asked to score the preoperative and postoperative views independently. The RAG scores were each assigned a number (1-3) and added to give a composite score (range 6-18) and these were averaged between the 5 assessors. There was a highly statistically significant difference between both preoperative and postoperative composite scores ( P <0.0001). A subgroup analysis of the postoperative composite score between the 2 surgical techniques showed no significant difference ( P =0.759). The RAG scoring system can be used to assess esthetic change following scaphocephaly correction and it provides both a visual analogue and a numerical indicator of change. This assessment method needs further validation but is a potentially reproducible way to score and compare esthetic outcomes in scaphocephaly correction.

Sagittal synostosis: does choice of intervention and its timing affect the long-term aesthetic and neurodevelopmental outcome? A single-institution study of 167 children

OBJECTIVE

Sagittal craniosynostosis (SC) is the most commonly encountered form of craniosynostosis. Despite its relative frequency, there remains significant heterogeneity in both operative management and follow-up between centers and a relative paucity of long-term outcome data in the literature. At the authors' institution, families of children presenting with SC are offered the following options: 1) conservative management with ophthalmic surveillance, 2) minimally invasive surgery at < 6 months of age (spring-assisted cranioplasty [SAC]) or 3) calvarial vault remodeling at any age (CVR). The authors reviewed outcomes for all children presenting with SC during a 5-year period, regardless of the treatment received.

METHODS

Consecutive children born between January 1, 2008, and December 31, 2012, presenting with SC were identified, and detailed chart reviews were undertaken. Demographic, surgical, perioperative, head shape, scar, and neurodevelopmental (behavioral, education, speech, and language) data were analyzed. The cohort was divided by type of surgery (none, SAC, or CVR) and by age at surgery (early, defined as ≤ 6 months; or late, defined as > 6 months) for comparison purposes.

RESULTS

A total of 167 children were identified, 129 boys and 38 girls, with a median age at presentation of 5.0 (range 0.4-135) months. Three families opted for conservative management. Of the 164 children who underwent surgery, 83 underwent SAC, 76 underwent CVR, and 5 underwent a "hybrid" procedure (CVR with springs). At a median age of 7.0 (range 0.5-12.3) years, there was no significant difference in concerns regarding head shape, scar, or neurodevelopmental outcomes between the early and late intervention groups over all procedures performed, or between the early or late SAC and CVR cohorts. There were more head shape concerns in the SAC group than in the CVR group overall (25.7% vs 11.8%, respectively; p = 0.026), although most of these concerns were minor and did not require revision.

CONCLUSIONS

In this cohort, regardless of operative intervention and timing of intervention, infants achieved similar neurodevelopmental outcomes. Minimally invasive surgery (SAC) appears to result in less complete correction of head shape than CVR, but this may be balanced by advantages in reduced operative time, hospitalization, and blood loss. SAC was equal to CVR in neuropsychological outcomes.

Persistent Cranial Defects After Endoscopic Sagittal Synostosis Surgery

INTRODUCTION

Incomplete cranial ossification is a rare complication of calvarial-vault remodeling for sagittal synostosis often requiring reoperation. Studies show an incidence ranging from 0.5% to 18%.

METHODS

Infants with sagittal synostosis who underwent endoscopic sagittal synostectomy and barrel stave osteotomies with postoperative orthotic helmeting between 2003 and 2021 were included with minimum follow-up until the completion of helmeting.

RESULTS

Of 90 patients, 86 met inclusion; 3 had defects (3.5%). Patients with and without cranial defects had no difference in age of surgery (113 versus 131 d), duration helmeting (6.6 versus 7.0 mo), or perioperative/postoperative complications. Two underwent reoperation for recurrence. Patients with cranial defects manifested the evidence of developmental concerns more than patients without (100% versus 16.9%).The average cranial defect size was 19.33 cm 2 and age at surgery 4.29 years. All were managed with cranial particulate bone grafting with addition of bone matrix and SonicWeld plate. The first had 6×6 cm posterior defect requiring cranioplasty at 4.86 years with excellent healing. The second had a 3×6 cm posterior and 1×1 cm anterior defect, underwent cranioplasty at 4.14 years with persistent 4×6 defect, requiring repeat cranioplasty at 5.3 years. The third had a 3×5 cm posterior defect and underwent cranioplasty at 3.88 years with continued defect, planning for repeat intervention.

CONCLUSIONS

This is the largest documented series of reoperations for incomplete ossification after endoscopic sagittal synostectomy with postoperative helmet treatment. The authors report a 3.5% rate of cranial defects, managed with bone grafting, bone matrix, and absorbable plates. Patients with poor ossification may have a propensity toward developmental concerns.

A Computational Framework to Predict Calvarial Growth: Optimising Management of Sagittal Craniosynostosis

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 debate in the craniofacial community while aspects of the biomechanics and mechanobiology are not well understood. Here, we describe a computational framework that enables us to predict and compare the calvarial growth following different reconstruction techniques for the management of sagittal synostosis. Our results demonstrate how different reconstruction techniques interact with the increasing intracranial volume. The framework proposed here can be used to inform optimum management of different forms of craniosynostosis, minimising the risk of functional consequences and secondary surgery.

Statistical shape analyses of corpus callosum changes at preoperative and postoperative scaphocephaly patients

PURPOSE

Scaphocephaly is the premature closure of the sagittal suture. The treatment strategies mainly focus on correcting the shape of the head, but there are very limited studies examining changes in brain structure. This study aimed to investigate shape differences in the shape of corpus callosum regarding the pre-treatment and post-treatment term at scaphocephaly patients.

METHODS

Cranium shape data were collected from the two-dimensional digital images. The generalized Procrustes analysis was used to obtain mean shapes in the pre- and postoperative phases. The shape deformation of the corpus callosum from the pre- to postoperative phases was evaluated using the thin plate spline method.

RESULTS

There is an enlargement of the splenium part of corpus callosum in the late group. In the early group, corpus callosum genu and body enlargement were observed in the postoperative period compared to the preoperative period, followed by a narrowing of the isthmus region.

CONCLUSION

This study showed structural deformations in the corpus callosum in scaphocephaly patients using head shape with the landmark-based geometric morphometric method by taking into consideration the topographic distribution. An enlargement at the splenium part of corpus callosum exposes after the cranial vault expansion depending on time.

Novel Method of Lateral Vault Modification in Scaphocephaly

BACKGROUND

Scaphocephaly is the commonest from of craniosynostosis. There are several surgical methods to correct this and is influenced by the areas affected. A common thread in any of these corrections is an attempt to increase the biparietal diameter by modifying the lateral vault panel (LVP). A simple and novel method is proposed.

MATERIALS AND METHOD

The records of all patients undergoing scaphocephaly correction in the craniofacial unit at the institution were reviewed from 2003 to 2019. There were 106 patients, 57 males, and 49 females. The age ranged from 6 months to 5 years with a mean of 11 months. The method of vault remodeling was LVP only in 36 (34%), subtotal vault remodeling in 59 (56%), and total vault remodeling in 11 (10%). All 106 patients underwent LVP remodeling as part of the procedure. One or 2 wedge excisions was performed to increase the curvature of the LVP and this panel was fixed on the outside of the temporal squame bone.

RESULTS

The patients were followed up for a minimum of 1 year. Satisfactory results were obtained. The mean preoperative cephalic index was 64% and the mean postoperative index was 75%. There were minor complications such as screw visibility in a few patients.

CONCLUSIONS

Wedge excisions of the LVP is a simple and effective maneuver that can be used as strategy when performing scaphocephaly correction.

Predicting and comparing three corrective techniques for sagittal craniosynostosis

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 assist with the management of craniosynostosis. The aim of this study was to compare and predict the outcomes of three reconstruction methods for sagittal craniosynostosis. Here, a generic finite element model was developed based on a patient at 4 months of age and was virtually reconstructed under all three different techniques. Calvarial growth was simulated to predict the skull morphology and the impact of different reconstruction techniques on the brain growth up to 60 months of age. Predicted morphology was then compared with in vivo and literature data. Our results show a promising resemblance to morphological outcomes at follow up. Morphological characteristics between considered techniques were also captured in our predictions. Pressure outcomes across the brain highlight the potential impact that different techniques have on growth. This study lays the foundation for further investigation into additional reconstructive techniques for sagittal synostosis with the long-term vision of optimizing the management of craniosynostosis.

Using Sensitivity Analysis to Develop a Validated Computational Model of Post-operative Calvarial Growth in Sagittal Craniosynostosis

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 can influence the prediction of skull growth and the pressure on the growing brain using this approach. Therefore, the aim of this study was to carry out a series of sensitivity studies to understand the effect of various input parameters on predicting the skull morphology of a sagittal synostosis patient post-operatively. Preoperative CT images of a 4-month old patient were used to develop a 3D model of the skull, in which calvarial bones, sutures, cerebrospinal fluid (CSF), and brain were segmented. Calvarial reconstructive surgery was virtually modeled and two intracranial content scenarios labeled “CSF present” and “CSF absent,” were then developed. FE method was used to predict the calvarial morphology up to 76 months of age with intracranial volume-bone contact parameters being established across the models. Sensitivity tests with regards to the choice of material properties, methods of simulating bone formation and the rate of bone formation across the sutures were undertaken. Results were compared to the in vivo data from the same patient. Sensitivity tests to the choice of various material properties highlighted that the defined elastic modulus for the craniotomies appears to have the greatest influence on the predicted overall skull morphology. The bone formation modeling approach across the sutures/craniotomies had a considerable impact on the level of contact pressure across the brain with minimum impact on the overall predicated morphology of the skull. Including the effect of CSF (based on the approach adopted here) displayed only a slight reduction in brain pressure outcomes. The sensitivity tests performed in this study set the foundation for future comparative studies using FE method to compare outcomes of different reconstruction techniques for the management of craniosynostosis.

Comparison of 2 Sagittal Craniosynostosis Repair Techniques: Spring-Assisted Surgery Versus Endoscope-Assisted Craniectomy With Helmet Molding Therapy

INTRODUCTION

This study compares anthropometric outcomes of 2 sagittal synostosis repair techniques: spring-assisted surgery and endoscope-assisted craniectomy with molding helmet therapy.

METHODS

Patients undergoing spring-assisted surgery (n = 27) or endoscope-assisted craniectomy with helmet therapy (n = 40) at separate institutions were retrospectively reviewed. Pre- and 1-year postoperative computed tomography (CT) or laser scans were analyzed for traditional cranial index (CI), adjusted cranial index (aCI), and cranial vault volume (CVV). Nine patient-matched scans were analyzed for measurement consistency.

RESULTS

The spring-assisted group was older at both time points (P < .050) and spring-assisted group CVV was larger preoperatively and postoperatively (P < .01). However, the change in CVV did not differ between the groups (P = .210). There was no difference in preoperative CI (helmet vs spring: 70.1 vs 71.2, P = .368) between the groups. Postoperatively, helmet group CI (77.0 vs 74.3, P = .008) was greater. The helmet group also demonstrated a greater increase in CI (6.9 vs 3.1, P < .001). The proportion of patients achieving CI of 75 or greater was not significantly different between the groups (helmet vs spring: CI, 65% vs 52%, P = .370). There was no detectable bias in CI between matched CT and laser scans. Differences were identified between scan types in aCI and CVV measurements; subsequent analyses used corrected CVV and aCI measures for laser scan measures.

CONCLUSIONS

Both techniques had equivalent proportions of patients achieving normal CI, comparable effects on cranial volume, and similar operative characteristics. The study suggests that there may be greater improvement in CI in the helmet group. However, further research should be performed.

Effect of Operative Timing and Bone Grafting on Postoperative Cephalometric Indices in Nonsyndromic Sagittal Synostosis

ABSTRACT

Surgical repair of sagittal suture craniosynostosis is highly variable, and optimal timing/use of bone grafts remains a subset of parameters that continue to be studied. We sought to compare cephalometric outcomes of early surgical intervention without bone grafting compared to later intervention with bone grafting. Patients undergoing primary surgical repair of nonsyndromic sagittal suture craniosynostosis between 2015 and 2019 were followed with preoperative measurements of cephalic index along with postoperative measurements at 6 months to 1 year, respectively. Nineteen patients undergoing cranial vault reconstruction were studied in 2 groups, namely those younger than 6 months who did not have bone grafting performed during primary repair (31.6%) and patients 6 months and older who underwent cranial vault reconstruction with bone grafting during primary repair (68.4%). Mean 6-month to 1-year postoperative cranial index was significantly increased in both groups (P < 0.001). The average cephalic index change for both groups (younger than 6 months without bone grafting, CI value change 9; 6 months and older with bone grafting; CI value change 6) was not significantly different with regards to 95% confidence interval (P = 0.30). Patients older than 6 months of age undergoing cranial vault reconstruction with bone grafting have similar cephalometric outcomes as their younger counterparts undergoing cranial vault remodeling without bone grafting. Bone grafting in the appropriate cohort may improve functional and esthetic outcomes without compromising primary surgical goals of improving cranial vault cephalometric indices.

GLI1 and AXIN2 Are Distinctive Markers of Human Calvarial Mesenchymal Stromal Cells in Nonsyndromic Craniosynostosis

All skeletal bones house osteogenic stem cell niches, in which mesenchymal stromal cells (MSC) provide progenitors for tissue growth and regeneration. They have been widely studied in long bones formed through endochondral ossification. Limited information is available on the composition of the osteogenic niche in flat bones (i.e., skull vault bones) that develop through direct membranous ossification. Craniosynostosis (CS) is a congenital craniofacial defect due to the excessive and premature ossification of skull vault sutures. This study aimed at analysing the expression of GLI1, AXIN2 and THY1 in the context of the human skull vault, using nonsyndromic forms of CS (NCS) as a model to test their functional implication in the aberrant osteogenic process. The expression of selected markers was studied in NCS patients' calvarial bone specimens, to assess the in vivo location of cells, and in MSC isolated thereof. The marker expression profile was analysed during in vitro osteogenic differentiation to validate the functional implication. Our results show that GLI1 and AXIN2 are expressed in periosteal and endosteal locations within the osteogenic niche of human calvarial bones. Their expression is higher in MSC isolated from calvarial bones than in those isolated from long bones and tends to decrease upon osteogenic commitment and differentiation. In particular, AXIN2 expression was lower in cells isolated from prematurely fused sutures than in those derived from patent sutures of NCS patients. This suggests that AXIN2 could reasonably represent a marker for the stem cell population that undergoes depletion during the premature ossification process occurring in CS.

Upward vectors for osteogenic distraction treatment in secondary chronic intracranial hypertension in children undergoing scaphocephaly surgery: 2 cases reported

The occurrence of secondary synostosis of coronal sutures at distance from H-craniectomy surgery for scaphocephaly concerns about 10% of children. Intracranial hypertension in these children remains exceptional but generally requires a surgical reoperation. Two children aged 3 and 5- months- old had been operated for scaphocephaly by H-craniectomy in two different hospital centers. Their clinical follow-up described a partial persistence of dolichocephalic deformity and an impression of parietal stenosis. During their growth, chronic headaches appeared with a complaint expressed at the ages of 4 and 5 years. In both cases, ophthalmic examination revealed significant bilateral papillary edema without loss of visual acuity. The imaging assessment (CT-scan and MRI) showed the absence of Chiari malformation and venous abnormality. For both, there was a compression image of the parietal lobes in relation to the persistence of a temporoparietal synostosis. An osteogenic parietal distraction permitted a volumetric brain expansion consecutive to the skull and meninges remodeling in only 6 months, associated with a leap forward acquisition, a normalization of the ophthalmic examination, and a complete loss of headaches. In conclusion, this new approach could be used in the case of chronic intracranial hypertension consecutive to a secondary parietal synostosis after a scaphocephaly surgery.

Statistical shape analyses of trigonocephaly patients

PURPOSE

Surgery is the first treatment option for patients with metopic craniosynostosis. Fronto-orbital advancement is the preferred method for correction of isolated trigonocephaly, but it is hard to understand whether surgery has been successful mainly in an early period. We aim to investigate the shape differences in the head shapes of trigonocephaly patients compared between preoperative and postoperative term.

METHODS

Cranial shape data were collected from the two-dimensional digital images. The Generalized Procrustes analysis was used to obtain mean shapes of the preoperative and postoperative term. The shape deformation of the frontal calvarium from preoperative to the postoperative term was evaluated using the thin-plate spline (TPS) method.

RESULTS

There was significant cranial shape difference between preoperative and postoperative term. The high-level deformations for preoperative to postoperative term determined seen in TPS graphic. Highest deformation was observed at the bifrontal dimension especially at nasion and posterior edge of the forehead.

CONCLUSIONS

In this study, we showed that the shape difference and structural deformation of the calvarium were correlated with the metopic craniosynostosis. The present study also shows that preoperative and postoperative head shapes of patients with trigonocephaly can be compared using the landmark-based geometrical morphometric method by taking into consideration the topographic distribution.

Predicting calvarial morphology in sagittal craniosynostosis

Early fusion of the sagittal suture is a clinical condition called, sagittal craniosynostosis. Calvarial reconstruction is the most common treatment option for this condition with a range of techniques being developed by different groups. Computer simulations have a huge potential to predict the calvarial growth and optimise the management of this condition. However, these models need to be validated. The aim of this study was to develop a validated patient-specific finite element model of a sagittal craniosynostosis. Here, the finite element method was used to predict the calvarial morphology of a patient based on its preoperative morphology and the planned surgical techniques. A series of sensitivity tests and hypothetical models were carried out and developed to understand the effect of various input parameters on the result. Sensitivity tests highlighted that the models are sensitive to the choice of input parameter. The hypothetical models highlighted the potential of the approach in testing different reconstruction techniques. The patient-specific model highlighted that a comparable pattern of calvarial morphology to the follow up CT data could be obtained. This study forms the foundation for further studies to use the approach described here to optimise the management of sagittal craniosynostosis.

An Overview of Modelling Craniosynostosis Using the Finite Element Method

Craniosynostosis is a medical condition caused by the early fusion of the cranial joint. The finite element method (FEM) is a computational technique that can answer a variety of "what if" questions in relation to the biomechanics of this condition. The aim of this study was to review the current literature that has used FEM to investigate the biomechanics of any aspect of craniosynostosis, being its development or its reconstruction. This review highlights that a relatively small number of studies (n = 10) has used FEM to investigate the biomechanics of craniosynostosis. Current studies set a good foundation for the future to take advantage of this method and optimize reconstruction of various forms of craniosynostosis.

Posterior Vault Distraction Osteogenesis in Nonsyndromic Patients: An Evaluation of Indications and Safety

PURPOSE

The purpose of this study was to evaluate the indications, safety, and short-term outcomes of posterior vault distraction osteogenesis (PVDO) in patients with no identified acrocephalosyndactyly syndrome (study) and to compare those to a syndromic cohort (controls).

METHODS

Demographic and perioperative data were recorded and compared across the study and control groups for those who underwent PVDO between January 2009 and December 2016. Univariate analysis was conducted using χ and Fisher exact tests for categorical variables, and Mann-Whitney U test for continuous variables.

RESULTS

Sixty-three subjects were included: 19 in the nonsyndromic cohort, 44 in the syndromic cohort. The cohorts had similar proportion of subjects exhibiting pansynostosis (42.1% of nonsyndromic versus 36.4% of syndromic, P = 0.667). The nonsyndromic cohort was significantly older (4.04 ± 3.66 years versus 2.55 ± 3.34 years, P = 0.046) and had higher rate of signs of raised intracranial pressure (68.4% versus 25.0%, P = 0.001) than the syndromic cohort. There was no significant difference in perioperative variables or rate of complications (P > 0.05). The mean total advancement distance achieved was similar, 27 ± 6 mm in the nonsyndromic versus 28 ± 8 mm in the syndromic cohort (P = 0.964). All nonsyndromic subjects with signs of raised intracranial pressure demonstrated improvement at an average follow-up of 22 months.

CONCLUSION

As in the syndromic patient, PVDO is a safe and, in the short-term, effective modality for cranial vault expansion in the nonsyndromic patient. The benefits and favorable perioperative profile of PVDO may therefore be extended to patient populations other than those with syndromic craniosynostosis.

Clinical evaluation of non-syndromic scaphocephaly surgically corrected with the procedure of total vertex craniectomy

The present investigation constitutes a retrospective evaluation of the outcome in children who received surgical correction of a scaphocephalic phenotype by median total vertex craniectomy. Between September 2009 and September 2015, a total of 35 infants with non-syndromic scaphocephaly were treated according to the same standardized operative technique of total vertex craniectomy by a single surgeon approach. At the time of surgery, the patients were between 3 and 12 months of age, with a median of 5 months. The mean duration of the procedure was 94 min. The duration of postoperative follow-up was a mean of 24 months (range 6-49 months). A total of 34 (97%) patients were successfully treated by total vertex craniectomy and were thus classified as category I according to the Whitaker score. Only one individual was assigned to category IV, necessitating secondary major craniofacial corrective surgery. Aesthetic outcomes were excellent in 34 cases and poor in one case. No major complication occurred. The reoperation rate was 3%. The surgical method we present herein is a wide median craniectomy which can be applied in young individuals with non-syndromic single-suture scaphocephaly.

Cranial morcellation decompression for refractory idiopathic intracranial hypertension in children

BACKGROUND

Primary idiopathic intracranial hypertension (PIIH) in children is rare and has a poorly understood pathophysiology. It is characterized by raised intracranial pressure (ICP) in the absence of an identified brain lesion. Diagnosis is usually confirmed by the measurement of a high cerebrospinal fluid (CSF) opening pressure and exclusion of secondary causes of intracranial hypertension. Refractory PIIH may lead to severe visual impairment. The purpose of this study was to evaluate a cranial morcellation decompression (CMD) technique as a new surgical alternative to stabilize intracranial pressure in PIIH.

MATERIALS AND METHODS

A literature review was carried out, disclosing only 7 pediatric cases of PIIH treated with surgical skull expansion. In addition, we describe here one case of our own experience treated by CMD.

CONCLUSIONS

CMD surgery is a safe and effective option to control refractory PIIH in selected patients.

Effects of thyroxine exposure on the Twist 1 +/- phenotype: A test of gene-environment interaction modeling for craniosynostosis

BACKGROUND

Craniosynostosis, the premature fusion of one or more of the cranial sutures, is estimated to occur in 1:1800 to 2500 births. Genetic murine models of craniosynostosis exist, but often imperfectly model human patients. Case, cohort, and surveillance studies have identified excess thyroid hormone as an agent that can either cause or exacerbate human cases of craniosynostosis.

METHODS

Here we investigate the influence of in utero and in vitro exogenous thyroid hormone exposure on a murine model of craniosynostosis, Twist 1 +/-.

RESULTS

By 15 days post-natal, there was evidence of coronal suture fusion in the Twist 1 +/- model, regardless of exposure. With the exception of craniofacial width, there were no significant effects of exposure; however, the Twist 1 +/- phenotype was significantly different from the wild-type control. Twist 1 +/- cranial suture cells did not respond to thyroxine treatment as measured by proliferation, osteogenic differentiation, and gene expression of osteogenic markers. However, treatment of these cells did result in modulation of thyroid associated gene expression.

CONCLUSION

Our findings suggest the phenotypic effects of the genetic mutation largely outweighed the effects of thyroxine exposure in the Twist 1 +/- model. These results highlight difficultly in experimentally modeling gene-environment interactions for craniosynostotic phenotypes. Birth Defects Research (Part A) 106:803-813, 2016. © 2016 Wiley Periodicals, Inc.