Implications of a vertex bulge following modified strip craniectomy for sagittal synostosis

Association of cranial base suture/synchondrosis fusion with severity of increased intracranial pressure in Crouzon syndrome

This study investigated how the fusion states of the cranial base is related to the degree of increased intracranial pressure (ICP) in patients with Crouzon syndrome. This retrospective cohort study enrolled patients who were diagnosed with Crouzon syndrome between May 2007 and April 2022. We categorized the patients into three groups: A, B, and C, according to the severity of increased ICP and the number of cranial vault remodeling procedures for corrective operation. The preoperative fusion states of the cranial base sutures/synchondroses were examined using facial bone computed tomography and compared between groups. Overall, 22 patients were included in Groups A, B, and C, including 8, 7, and 7 patients, respectively. The preoperative average grades of the total cranial base suture/synchondrosis fusion appeared to significantly increase with severity, except for the frontoethmoidal suture, which showed the opposite tendency. In the subgroup analysis, frontosphenoidal, sphenoparietal, sphenosquamosal, parietomastoid, and occipitomastoid suture and petro-occipital synchondrosis were associated with earlier fusion in the more severe group. Premature closure of the cranial base sutures/synchodroses seems to be associated with increased ICP severity in patients with Crouzon syndrome. Precise evaluation of minor sutures/synchondroses at the first visit might help build subsequent operative plans and predict disease prognosis.

Suturectomies Assisted by Cranial Orthosis Remodeling for the Treatment of Craniosynostosis Can Be Performed Without an Endoscope

BACKGROUND

Minimally-invasive endoscopic strip-craniectomy (or suturectomy) for the repair of craniosynostosis combined with postoperative cranial orthotic molding has been widely adopted in the past 2 decades, proving itself as a safe and effective procedure. Over time the authors transitioned from performing an endoscopic strip-craniectomy, to performing the same surgery without the endoscope. The authors here describe our technique and compare its results to those published in the literature for endoscopic suturectomies.

METHODS

A retrospective chart review was performed for patients with nonsyndromic craniosynostosis who underwent minimally-invasive nonendoscopic suturectomy between 2019 and 2020 at our institution.

RESULTS

Thirteen patients (11 males; 2 females) were operated including 5 Metopic, 5 Sagittal, 2 coronal, and 1 lambdoid craniosynostosis. The average age at surgery was 4.35 months. The average length of surgery was 71 minutes. Averaged intraoperative estimated blood loss was 31.54 mL. Eleven patients received a blood transfusion (most before performing the skin incision) with a mean amount of 94.62 mL of blood transfused during surgery. The mean hemoglobin at discharge was 10.38 mg/dL. There was only 1 intraoperative mild complication. The mean intrahospital length of stay was 1.77 days with no postoperative complications noted. All patients initiated remodeling orthotic treatment following surgery. Long-term follow-up scans were available for 8 patients (5 metopic, 2 sagittal, and 1 lambdoid) with an average follow-up of 9 months. In all cases, there was a significant improvement in the skull width at the synostosis location as well as in the skull proportions and symmetry. The above outcomes are similar to those published in the literature for endoscope-assisted strip-craniectomies.

CONCLUSIONS

Suturectomies assisted with cranial orthosis remodeling for the treatment of all types of nonsyndromic craniosynostosis can be performed without an endoscope while maintaining minimal-invasiveness, good surgical results, and low complication rates.

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.

Secondary Raised Intracranial Pressure After Cranial Vault Remodeling for Isolated Sagittal Craniosynostosis

ABSTRACT

The management of sagittal craniosynostosis has evolved over the decades as teams seek to refine their surgical approaches to idealize head shape with the least possible morbidity. Here, the authors identify the incidence of raised intracranial pressure (ICP) and its risk factors, requiring secondary surgical intervention after cranial vault remodeling (CVR) procedure at a single tertiary referral craniofacial unit. A retrospective case-control study was performed on the patients with isolated non-syndromic sagittal craniosynostosis. All patients who underwent CVR in our unit and had a minimum of 1.5 years follow-up were included. One hundred and eighty-four patients (134 male and 50 female) who underwent primary CVR surgery for isolated sagittal craniosynostosis were included. Thirteen patients (7.07%) had clinical evidence of late raised ICP resulting in repeat CVR procedures. Higher incidence of raised ICP in patients who had primary surgery before 6 months than after or at 6 months of age (P = 0.001). There were 23.5%, 5.6%, 3.2%, and 1.9% of secondary raised ICP patients who underwent the primary surgery between 1999-2004, 2005-2010, 2011-2015 and 2016-2018, respectively (P = 0.024). The risk of secondary raised ICP was higher in patients with isolated sagittal craniosynostosis whose primary surgery occurred before the age of 6 months (two times more likely). More extensive CVR can be performed safely in sagittal synostosis with promising outcomes. The late presentation with raised ICP reinforces the importance of long-term multidisciplinary protocol-based follow-up.

Neosagittal Suture Formation after Endoscopic Sagittal Strip Craniectomy: A Case Report and Literature Review

The fate of the excised synostotic suture in craniosynostosis remains relatively understudied. The purpose of this report is to describe a case of neosagittal suture formation following endoscopic excision of a pathology-proven synostotic suture, with CT demonstration of complete reossification in the areas adjacent to the neosagittal suture. We additionally review the existing literature on neosuture formation that has been published over the past 50 years. We conclude that continued investigation is warranted, both through histological comparison of normal and neosutures and through studies to determine clinical risk factors, as this may improve our understanding of the underlying mechanism of pathologic premature suture fusion in craniosynostosis.

The role of ICP overnight monitoring (ONM) in children with suspected craniostenosis

PURPOSE

Secondary craniostenosis is a relevant problem pediatric neurosurgeons are confronted with and poses challenges regarding reliable diagnosis of raised ICP, especially in case of absent or questionable papilledema. How to identify children with elevated ICP is still controversial and diagnostics vary. We report on our experience with computerized ICP ONM in relation to imaging derived parameters.

METHODS

Thirty-four children with primary or secondary craniostenosis and clinical suspicion of raised ICP were investigated. We compared clinical signs, history, and radiographic assessment with the results of computerized ICP ONM. Differences were significant at a p < 0.05.

RESULTS

Baseline ICP was significantly higher in patients with combined suture synostosis, who also had a higher rate of questionable papilledema. Children with narrowed external CSF spaces in MRI had significantly higher ICP levels during REM sleep. Mean RAP was significantly elevated in patients with multi-suture synostosis, indicating poor intracranial compensatory reserve. Syndromal craniostenosis was associated with elevated ICP, RAP was significantly lower, and skull X-rays showed more impressions (copper beaten skull). RAP increased with more severe impressions only to decline in most severe abnormalities, indicating exhaustion of cerebrovascular reserve at an upper ICP breakpoint of 23.9 mmHg. Headaches correlated to lower ICP and were not associated with more severe X-ray abnormalities.

CONCLUSION

Narrowed external CSF spaces in MRI seem to be associated to elevated ICP. Skull X-rays can help to identify patients at risk for chronically elevated ICP. Severe X-ray changes correlate with exhausted cerebrovascular reserve as indicated by RAP decline. Only ICP monitoring clearly identifies raised ICP and low brain compliance. Thus, in cases with ambiguous imaging, ONM constitutes an effective tool to acquire objective data for identification of surgical candidates.

Sagittal Craniosynostosis with Uncommon Anatomical Pathologies in a 56-Year-Old Male Cadaver

Sagittal craniosynostosis (CS) is a pathologic condition that results in premature fusion of the sagittal suture, restricting the transverse growth of the skull leading in some cases to elevated intracranial pressure and neurodevelopmental delay. There is still much to be learned about the etiology of CS. Here, we report a case of 56-year-old male cadaver that we describe as sagittal CS with torus palatinus being an additional anomaly. The craniotomy was unsuccessful (cephalic index, CI = 56) and resulted in abnormal vertical outgrowth of the craniotomized bone strip. The histological analysis of the latter revealed atypical, noncompensatory massive bone overproduction. Exome sequencing of DNA extracted from the cadaveric tissue specimen performed on the Next Generation Sequencing (NGS) platform yielded 81 genetic variants identified as pathologic. Nine of those variants could be directly linked to CS with five of them targeting RhoA GTPase signaling, with a potential to make it sustained in nature. The latter could trigger upregulated calvarial osteogenesis leading to premature suture fusion, skull bone thickening, and craniotomized bone strip outgrowth observed in the present case.

Osseous Convexity at the Anterior Fontanelle: A Presentation of Metopic Fusion?

BACKGROUND

Craniosynostosis, or a premature fusion of 1 or more cranial vault sutures, results in characteristic head shape deformities. In previous reports, an osseous prominence at the anterior fontanelle has been suggestive of adjacent suture fusion and local elevation in intracranial pressure (ICP). This prominence has been termed the "volcano" sign, and has been described in the anterior fusion of the sagittal suture and serves as an indication for surgery.

METHODS

Two patients presented for head shape evaluation with mild metopic ridging and anterior fontanellar osseous convexities consistent with the volcano sign. Low-dose computed tomography imaging was performed in both patients due to concern for underlying craniosynostosis with elevated locoregional ICP.

RESULTS

In both patients, imaging was significant for a localized, superior forehead metopic fusion, as well as a bony, convex prominence at the site of the ossified anterior fontanelle. There were no other clinical or radiologic signs or symptoms to suggest elevated ICP. Surgery was not indicated in either patient.

CONCLUSIONS

Here the authors present 2 patients with osseous convexities at the site of the closed anterior fontanelle without signs or symptoms of elevated ICP, or classic signs of metopic synostosis. The authors hypothesize that this pattern may be due to a form of mechanically induced premature fusion of a normal metopic suture that is focused superiorly at the bregma, with minimal resultant restriction of overall skull growth. This is in contrast to metopic synostosis, which primarily has a sutural pathology and leads to characteristic findings of hypotelorism and trigonocephaly.

Sleep Architecture Linked to Airway Obstruction and Intracranial Hypertension in Children with Syndromic Craniosynostosis

BACKGROUND

Children with syndromic craniosynostosis often have obstructive sleep apnea and intracranial hypertension. The authors aimed to evaluate (1) sleep architecture, and determine whether this is influenced by the presence of obstructive sleep apnea and/or intracranial hypertension; and (2) the effect of treatment on sleep architecture.

METHODS

This study included patients with syndromic craniosynostosis treated at a national referral center, undergoing screening for obstructive sleep apnea and intracranial hypertension. Obstructive sleep apnea was identified by polysomnography, and categorized into no, mild, moderate, or severe. Intracranial hypertension was identified by the presence of papilledema on funduscopy, supplemented by optical coherence tomography and/or intracranial pressure monitoring. Regarding sleep architecture, sleep was divided into rapid eye movement or non-rapid eye movement sleep; respiratory effort-related arousals and sleep efficiency were scored.

RESULTS

The authors included 39 patients (median age, 5.9 years): 19 with neither obstructive sleep apnea nor intracranial hypertension, 11 with obstructive sleep apnea (four moderate/severe), six with intracranial hypertension, and three with obstructive sleep apnea and intracranial hypertension. Patients with syndromic craniosynostosis, independent of the presence of mild obstructive sleep apnea and/or intracranial hypertension, have normal sleep architecture compared with age-matched controls. Patients with moderate/severe obstructive sleep apnea have a higher respiratory effort-related arousal index (p < 0.01), lower sleep efficiency (p = 0.01), and less rapid eye movement sleep (p = 0.04). An improvement in sleep architecture was observed following monobloc surgery (n = 5; rapid eye movement sleep, 5.3 percent; p = 0.04).

CONCLUSIONS

Children with syndromic craniosynostosis have in principle normal sleep architecture. However, moderate/severe obstructive sleep apnea does lead to disturbed sleep architecture, which fits within a framework of a unifying theory for obstructive sleep apnea, intracranial hypertension, and sleep.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, II.

A Genetic-Pathophysiological Framework for Craniosynostosis

Craniosynostosis, the premature fusion of one or more cranial sutures of the skull, provides a paradigm for investigating the interplay of genetic and environmental factors leading to malformation. Over the past 20 years molecular genetic techniques have provided a new approach to dissect the underlying causes; success has mostly come from investigation of clinical samples, and recent advances in high-throughput DNA sequencing have dramatically enhanced the study of the human as the preferred "model organism." In parallel, however, we need a pathogenetic classification to describe the pathways and processes that lead to cranial suture fusion. Given the prenatal onset of most craniosynostosis, investigation of mechanisms requires more conventional model organisms; principally the mouse, because of similarities in cranial suture development. We present a framework for classifying genetic causes of craniosynostosis based on current understanding of cranial suture biology and molecular and developmental pathogenesis. Of note, few pathologies result from complete loss of gene function. Instead, biochemical mechanisms involving haploinsufficiency, dominant gain-of-function and recessive hypomorphic mutations, and an unusual X-linked cellular interference process have all been implicated. Although few of the genes involved could have been predicted based on expression patterns alone (because the genes play much wider roles in embryonic development or cellular homeostasis), we argue that they fit into a limited number of functional modules active at different stages of cranial suture development. This provides a useful approach both when defining the potential role of new candidate genes in craniosynostosis and, potentially, for devising pharmacological approaches to therapy.

Frontobiparietal remodeling with or without a widening bridge for sagittal synostosis: comparison of 2 cohorts for aesthetic and functional outcome

OBJECT Various techniques to correct sagittal synostosis have been described. The authors of this study assess the results of 2 techniques for late complete cranial remodeling and test the hypothesis that adding a widening bridge would improve outcome. METHODS In this retrospective study, the authors evaluated patients with nonsyndromic sagittal synostosis-those who underwent frontobiparietal remodeling (FBR) and those who underwent modified FBR (MFBR) involving the introduction of a bony bridge to increase the width of the skull. Outcomes for both groups are described in terms of the aesthetic results assessed on photographs and any changes in the cranial index (CI) and head circumference over time, the presence of papilledema, and complaints of headache. The effect of the surgical technique on CI and head circumference over time was assessed using linear regression analysis, with adjustment for preoperative CI and head circumference. RESULTS Sixty-nine patients with isolated sagittal synostosis were included in this study: 35 underwent MFBR and 34 underwent the original technique of FBR. The mean follow-up period was 7 years. In the 1st year after surgery, mean CI improved by 9% in the FBR group and by 12% in the MFBR group. One year after surgery, CI in the MFBR group was on average 4.7% higher than that in the FBR group (p < 0.001). During follow-up, CI decreased in both groups; however, at all time points CI was significantly higher in the MFBR group than in the FBR group. The impact of surgical technique on CI was less important than the impact of preoperative CI (R(2)= 0.26 vs 0.54), and this applied at all time points during follow-up. Head circumference declined during follow-up in both groups. It was influenced by preoperative head circumference, but not by surgical technique. Aesthetic outcome, prevalence of headache (42%), and papilledema (7%) were comparable in both groups. CONCLUSIONS Adding a widening bridge to late complete remodeling significantly improved CI and helped to prevent CI from decreasing in the long term. This addition did not affect the head circumference growth curve. Despite a mean head circumference remaining at +1 SD, patients continued to develop papilledema postoperatively (7%).

Intracranial hypertension after surgical correction for craniosynostosis: a systematic review

OBJECT

The authors’ aim was perform a systematic review on the incidence of intracranial hypertension (IH) after surgery for craniosynostosis.

METHODS

A systematic literature review was conducted using PubMed to assess the rate of postoperative IH in studies published between 1985 and 2014. Inclusion criteria were 1) English-language literature; 2) human subjects; 3) pediatric cases; and 4) postoperative IH confirmed with invasive intracranial pressure monitoring.

RESULTS

Seven studies met inclusion criteria. IH was reported to be present in 5% of patients postoperatively with sagittal synostosis and 4% of patients with all forms of nonsyndromic craniosynostosis. Inadequate numbers were available to determine the incidence of postoperative IH for syndromic and individual nonsyndromic sutural synostosis based on the inclusion criteria. Surgical groups were subdivided into cranial remodeling procedures without orbital advancement and craniofacial procedures with orbital advancement. IH was reported to be present in 5% of patients with all forms of nonsyndromic sutural stenosis after cranial remodeling procedures and 1% after craniofacial advancement.

CONCLUSIONS

Postoperative development of elevated intracranial pressure has been described by multiple institutions, but the variation in how IH is determined and the multiple surgical procedures to correct craniosynostosis has limited the number of studies subject to a meta-analysis. Nonetheless, this entity deserves special attention, and further studies are required to determine the true incidence of postoperative IH, including the role of various surgical procedures on its incidence. The long-term consequences of chronic IH in this group of patients also need to be evaluated.

The incidence of raised intracranial pressure in nonsyndromic sagittal craniosynostosis following primary surgery

OBJECT Raised intracranial pressure (ICP) is recognized to occur in patients with nonsyndromic isolated sagittal craniosynostosis (SC) prior to surgery. However, the incidence of raised ICP following primary surgery is rarely reported and there appears to be a widely held assumption that corrective surgery for SC prevents the later development of intracranial hypertension. This study reports the incidence of postoperative raised ICP in a large cohort of patients with SC treated by 1 of 2 surgical procedures in a single craniofacial unit. METHODS A retrospective review was performed of all patients with SC who underwent either a modified strip craniectomy (MSC) or calvarial remodeling (CR) procedure under the care of the Oxford Craniofacial Unit between 1995 and 2010 and who were followed up for more than 2 years. The influence of patient age at surgery, year of surgery, sex, procedure type, and the presence of raised ICP preoperatively were analyzed. RESULTS Two hundred seventeen children had primary surgery for SC and were followed up for a mean of 86 months. The overall rate of raised ICP following surgery was 6.9%, occurring at a mean of 51 months after the primary surgical procedure. Raised ICP was significantly more common in those patients treated by MSC (13 of 89 patients, 14.6%) than CR (2 of 128 patients, 1.6%). Also, raised ICP was more common in patients under 1 year of age, the majority of whom were treated by MCS. No other factor was found to have a significant effect. CONCLUSIONS Postoperative raised ICP was found in more than 1 in 20 children treated for nonsyndromic SC in this series. It was significantly influenced by the primary surgical procedure and age at primary surgery. Careful long-term follow-up is essential if children who develop raised ICP following surgery are not to be overlooked.

Mechanics of the brain: perspectives, challenges, and opportunities

The human brain is the continuous subject of extensive investigation aimed at understanding its behavior and function. Despite a clear evidence that mechanical factors play an important role in regulating brain activity, current research efforts focus mainly on the biochemical or electrophysiological activity of the brain. Here, we show that classical mechanical concepts including deformations, stretch, strain, strain rate, pressure, and stress play a crucial role in modulating both brain form and brain function. This opinion piece synthesizes expertise in applied mathematics, solid and fluid mechanics, biomechanics, experimentation, material sciences, neuropathology, and neurosurgery to address today’s open questions at the forefront of neuromechanics. We critically review the current literature and discuss challenges related to neurodevelopment, cerebral edema, lissencephaly, polymicrogyria, hydrocephaly, craniectomy, spinal cord injury, tumor growth, traumatic brain injury, and shaken baby syndrome. The multi-disciplinary analysis of these various phenomena and pathologies presents new opportunities and suggests that mechanical modeling is a central tool to bridge the scales by synthesizing information from the molecular via the cellular and tissue all the way to the organ level.

Secondary bicoronal synostosis after metopic craniosynostosis surgical reconstruction

Re-synostosis after standard surgical procedures for nonsyndromic craniosynostosis is a rare event, which can occur at the same suture or rarely in adjacent sutures. Here, we report 2 patients with primary metopic craniosynostosis who developed bicoronal synostosis in previously opened sutures several months after surgery.

Results of early surgery for sagittal suture synostosis: long-term follow-up and the occurrence of raised intracranial pressure

PURPOSE

Numerous techniques are used to correct sagittal synostosis. Although cosmetic results and operative complications are well documented, little is known about functional outcome. In our institution, the technique for extended strip craniectomy evolved over time. This study compares cosmetic results, complications, and signs of raised intracranial pressure (ICP) between the variants of the extended strip craniectomy.

METHODS

Seventy-nine consecutive patients undergoing early extended strip craniectomy for scaphocephaly (2002-2008) were included. Four techniques were used: A, a simple bilateral parietal flap with out-fracturing of the bone flap; B, C, and D included remodeling of the parietal flap by adding triangular cuts and bending or suturing the resulting fingers. In technique D, the sagittal strip was rotated and fixed between the parietal flaps. Data on head circumference (HC), skull X-ray, and fundoscopy were collected prospectively.

RESULTS

For all patients, the average cranial index (CI) was 74 after 3 months and 72 after 2 years. Although technique D resulted in the best initial improvement, there was no significant percentage increase in CI after 24 months between the four techniques. Postoperatively, 9 % of the patients developed papilledema, 42 % developed a fontanel bulge, and 57 % had diminished HC. Four patients were reoperated on because of raised ICP.

CONCLUSIONS

Postoperative CI is mainly determined by preoperative CI and hardly affected by type of extended strip craniectomy. Signs of raised ICP occurred more frequently than expected, therefore structural follow-up is required to detect such signs. Technique and timing of surgery should aim at creating sufficient intracranial volume.

Delayed intracranial hypertension after cranial vault remodeling for nonsyndromic single-suture synostosis

OBJECT

Delayed intracranial hypertension may occur after cranial vault remodeling for synostosis and may result in visual loss and developmental delay. Delayed intracranial hypertension is relatively common in children with syndromic, multisuture synostosis, but the incidence is poorly defined in children with single-suture nonsyndromic synostosis. This study evaluates the frequency of reoperation for delayed intracranial hypertension after single-suture synostosis repair.

METHODS

Patients who had undergone cranial vault remodeling for nonsyndromic single-suture synostosis and were treated at a single tertiary pediatric hospital between July 2000 and December 2010 were analyzed for the occurrence of delayed intracranial hypertension and reoperation for cranial vault remodeling.

RESULTS

Eighty-one patients with clinical follow-up of at least 3 years were analyzed from a total of 156 consecutive patients. The average patient age at the initial operation was 9.1 months. Five (6.2%) of 81 patients presented with delayed clinical and ophthalmological signs and symptoms of intracranial hypertension following initial cranial vault reconstruction, confirmed indirectly in each case by CT findings and directly by intracranial pressure monitoring. These 5 patients underwent repeat cranial vault reconstruction.

CONCLUSIONS

Calvarial growth restriction and intracranial hypertension occur sporadically following primary cranial vault reconstruction for single-suture nonsyndromic cranial synostosis. In this series, delayed intracranial hypertension occurred only in male patients who underwent primary repair of isolated sagittal synostoses at an age less than or equal to 5 months.

Outcome analysis of morcellation craniotomy with distraction osteogenesis for scaphocephaly

BACKGROUND

Techniques for sagittal synostosis correction continue to evolve, thus resulting in improved outcomes and minimized morbidity. Spring-assisted cranioplasty and strip craniotomy with postoperative helmet usage are simple minimally invasive surgeries. However, these procedures are only useful in younger patients (generally up to 9 months of age); older children usually undergo total cranial remodeling, which is more stressful. We have developed a procedure combining morcellation craniotomy with distraction osteogenesis (MoD), which we have been performing since 2000. Here, we describe and evaluate this method of treatment.

METHODS

Seven patients who underwent MoD for isolated sagittal synostosis were followed for 10 years postoperatively. The control group consisted of 7 patients who had undergone total cranial remodeling in the period immediately preceding the MoD operations. Cephalography, clinical examinations, medical record data and medical photographs were used to evaluate and compare the 2 groups.

RESULTS

In comparison with total cranial remodeling, the MoD procedure resulted in a significantly shorter mean operation time and a significantly lower mean blood transfusion volume. The postoperative cephalic index was not significantly different between the MoD (75.8 ± 0.9) and the control groups (75.6 ± 1.4), and satisfactory cranial shape volumes were achieved without serious complications.

CONCLUSION

The MoD procedure is a safe, effective and reliable technique for dynamic total skull remodeling with minimal morbidity. It can be used to improve upon previous surgical concepts for treating scaphocephaly, particularly in older patients.

Frank-ter Haar syndrome associated with sagittal craniosynostosis and raised intracranial pressure

BACKGROUND

Frank-ter Haar syndrome is a rare disorder associated with skeletal, cardiac, ocular and craniofacial features including hypertelorism and brachycephaly. The most common underlying genetic defect in Frank-ter Haar syndrome appears to be a mutation in the SH3PXD2B gene on chromosome 5q35.1. Craniosynostosis, or premature fusion of the calvarial sutures, has not previously been described in Frank-ter Haar syndrome.

CASE PRESENTATION

We present a family of three affected siblings born to consanguineous parents with clinical features in keeping with a diagnosis of Frank-ter Haar syndrome. All three siblings have a novel mutation caused by the deletion of exon 13 of the SH3PXD2B gene. Two of the three siblings also have non-scaphocephalic sagittal synostosis associated with raised intracranial pressure.

CONCLUSION

The clinical features of craniosynostosis and raised intracranial pressure in this family with a confirmed diagnosis of Frank-ter Haar syndrome expand the clinical spectrum of the disease. The abnormal cranial proportions in a mouse model of the disease suggests that the association is not coincidental. The possibility of craniosynostosis should be considered in individuals with a suspected diagnosis of Frank-ter Haar syndrome.

Atypical Crouzon Syndrome with a Novel Cys62Arg Mutation in FGFR2 Presenting with Sagittal Synostosis

The management of a 1-year-old boy with Crouzonoid features is presented with a description of molecular genetic investigations that revealed a previously unreported mutation of the fibroblast growth factor receptor 2 (FGFR2) gene encoding the amino acid substitution p.Cys62Arg within the immunoglobin-like (IgI) domain. The patient presented in atypical fashion with severe sagittal synostosis but only mild exorbitism and hypertelorism. Owing to the progressively increasing size of the cranial occipital bullet, a total calvarial modeling procedure was performed at 8 months of age to correct the craniofacial deformity.

Standard genetic testing of the major mutational “hotspots” associated with craniosynostosis was initially negative. However, further testing for atypical sites of mutation revealed a heterozygous nucleotide substitution (c.184T>C) in exon 3 of FGFR2. This mutation has not been previously reported and is only the second to be identified in the IgI domain; it was not present in either parent, indicating that it had arisen de novo. The child remains well 6 months postoperatively but will be monitored more closely compared with the usual protocol for nonsyndromic sagittal synostosis owing to the potential for increased risk of secondary complications.

Key learning points from this case include the need for careful phenotypic evaluation of children presenting with apparently isolated sagittal synostosis and genetic testing for atypical mutations if the usual hotspots are negative.

Prevalence and complications of single-gene and chromosomal disorders in craniosynostosis

OBJECTIVES

We describe the first cohort-based analysis of the impact of genetic disorders in craniosynostosis. We aimed to refine the understanding of prognoses and pathogenesis and to provide rational criteria for clinical genetic testing.

METHODS

We undertook targeted molecular genetic and cytogenetic testing for 326 children who required surgery because of craniosynostosis, were born in 1993-2002, presented to a single craniofacial unit, and were monitored until the end of 2007.

RESULTS

Eighty-four children (and 64 relatives) had pathologic genetic alterations (86% single-gene mutations and 14% chromosomal abnormalities). The FGFR3 P250R mutation was the single largest contributor (24%) to the genetic group. Genetic diagnoses accounted for 21% of all craniosynostosis cases and were associated with increased rates of many complications. Children with an initial clinical diagnosis of nonsyndromic craniosynostosis were more likely to have a causative mutation if the synostoses were unicoronal or bicoronal (10 of 48 cases) than if they were sagittal or metopic (0 of 55 cases; P = .0003). Repeat craniofacial surgery was required for 58% of children with single-gene mutations but only 17% of those with chromosomal abnormalities (P = .01).

CONCLUSIONS

Clinical genetic assessment is critical for the treatment of children with craniosynostosis. Genetic testing of nonsyndromic cases (at least for FGFR3 P250R and FGFR2 exons IIIa/c) should be targeted to patients with coronal or multisuture synostoses. Single-gene disorders that disrupt physiologic signaling in the cranial sutures often require reoperation, whereas chromosomal abnormalities follow a more-indolent course, which suggests a different, secondary origin of the associated craniosynostosis.

A single-center experience with symptomatic postoperative calvarial growth restriction after extended strip craniectomy for sagittal craniosynostosis

OBJECT

Sagittal synostosis accounts for the most common form of craniosynostosis, occurring with an incidence of 1 in 2000-5000 live births. In most cases of single-suture, nonsyndromic sagittal synostosis, a single operation is all that is required to achieve a reasonable cosmetic result. However, there are a number of patients who may experience symptomatic postoperative calvarial growth restriction secondary to fibrosis of newly formed bone and pericranium that replace the surgically removed sagittal suture, or due to fusion of other previously open sutures leading to increased intracranial pressure, necessitating a second operation.

METHODS

A retrospective review was conducted of all cases involving infants who had undergone an extended sagittal strip craniectomy with bilateral parietal wedge osteotomies at our institution between 1990 and 2006 for single-suture, nonsyndromic sagittal craniosynostosis. The frequency with which subsequent operations were required for cranial growth restriction was then defined.

RESULTS

There were a total of 164 patients with single-suture nonsyndromic sagittal synostosis. Follow-up data were available for 143 of these patients. The average age at time of initial operation was 5.25 months, and the mean duration of follow-up was 43.85 months. There were 2 patients (1.5%) who required a second operation for symptomatic postoperative calvarial growth restriction.

CONCLUSIONS

Recurrence of synostosis with resultant increased intracranial pressure in cases of single-suture, nonsyndromic sagittal craniosynostosis is an uncommon event, but does occur sporadically and unpredictably. Therefore, we recommend routine neurosurgical follow up for at least 5 years, with regular ophthalmological examinations to assess for papilledema.