Skull vault growth in craniosynostosis

Minor Suture Fusion is Associated With Chiari Malformation in Nonsyndromic Craniosynostosis

Here, we focused on the association between minor suture fusion and Chiari malformation (CM) occurrence in nonsyndromic craniosynostosis (NSC), and evaluated how the minor suture affects the posterior cranial fossa by measuring the posterior fossa deflection angle (PFA). In this retrospective study, the clinical records of 137 patients who underwent surgery for NSC at Aichi Children's Health and Medical Center between April 2010 and May 2022 were analyzed. Clinical data from Aichi Developmental Disability Center Central Hospital was collected for 23 patients as the external validation set. Among the 137 patients, 123 were diagnosed with NSC and the remaining 14 with syndromic craniosynostosis. Of the 123 NSC patients, 23 patients presented with CM. Multivariate analysis showed that occipito-mastoid fusion was the only significant risk factor for CM ( P =0.0218). Within the NSC group, CM patients had a significantly increased PFA (6.33±8.10 deg) compared with those without CM (2.76±3.29 deg, P =0.0487). Nonsyndromic craniosynostosis patients with occipito-mastoid suture fusion had a significantly increased PFA (6.50±7.60 deg) compared with those without occipito-mastoid fusion (2.60±3.23 deg, P =0.0164). In the validation cohort, occipito-mastoid suture fusion was validated as an independent risk factor for CM in univariate analysis. Minor suture fusion may cause CM associated with NSC. Chiari malformation could develop due to an increased PFA due to minor suture fusion, which causes growth disturbance in the affected side and compensatory dilation in the contralateral side within the posterior cranial fossa.

Impact of age at endoscopic metopic synostosis repair on anthropometric outcomes

OBJECTIVE

Endoscopic strip craniectomy for metopic craniosynostosis relies on rapid growth and postoperative helmeting for correction. Endoscopic repair is generally performed before patients reach 4 months of age, and outcomes in older patients have yet to be quantified. Here, the authors examined a cohort of patients treated with endoscopic repair before or after 4 months of age to determine aesthetic outcomes of delayed repairs.

METHODS

Data from eligible patients were retrospectively assessed and aggregated in a dedicated metopic synostosis database. Inclusion criteria were radiographically confirmed metopic synostosis and endoscopic treatment. Patients were dichotomized into two groups: those younger than 4 months and those 4 months or older at the time of repair. The frontal width and interfrontal divergence angle (IFDA) were measured on reconstructed CT images. These measurements, alongside operative time, estimated blood loss, and transfusion rates, were compared between groups using the Student t-test or chi-square test.

RESULTS

The study population comprised 28 patients treated before 4 months of age and 8 patients treated at 4-6 months of age. Patient sex and perioperative complications did not differ by age group. Older age at repair was not significantly associated with 1-year postoperative IFDA (140° ± 4.2° vs 142° ± 5.0°, p = 0.28) or frontal width (84 ± 5.2 vs 83 ± 4.4 mm, p = 0.47).

CONCLUSIONS

One-year postoperative IFDA and frontal width do not differ significantly between patients treated before and after 4 months of age. Further study with longer follow-up is necessary to confirm the longevity of these results at skeletal maturity.

Cranial suture morphometry and mechanical response to loading: 2D vs. 3D assumptions and characterization

Cranial sutures are complex soft tissue structures whose mechanics are often studied due to their link with bone growth in the skull. Researchers will often use a cross-sectional two-dimensional slice to define suture geometry when studying morphometry and/or mechanical response to loading. However, using a single cross section neglects the full suture complexity and may introduce significant errors when defining their form. This study aims to determine trends in suture path variability through skull thickness in a swine model and the implications of using a 'representative' cross section on mechanical modeling. To explore these questions, a mixture of quantitative analysis of computed tomography images and finite element models was used. The linear interdigitation and width of coronal and sagittal sutures were analyzed on offset transverse planes through the skull thickness. It was found that sagittal suture width and interdigitation were largely consistent through the skull thickness, whereas the coronal suture showed significant variation in both. The finite element study found that average values of displacement and strain were similar between the two-dimensionally variable and three-dimensionally variable models. Larger ranges and more complex distributions of strain were found in the three-dimensionally variable model. Outcomes of this study indicate that the appropriateness of using a representative cross section to describe suture morphometry and predict mechanical response should depend on specific research questions and goals. Two-dimensional approximations can be sufficient for less-interdigitated sutures and when bulk site mechanics are of interest, while taking the true three-dimensional geometry into account is necessary when considering spatial variability and local mechanical response.

Clinical Features and the Use of Three-Dimensional Imaging for Unilateral Lambdoid Synostosis

INTRODUCTION

True isolated lambdoid craniosynostosis is rare. It requires corrective surgery to prevent intracranial pressure and aesthetic stigma by significant dyscrania. We summarize our case series for lambdoid craniosynostosis outlining the pathophysiology, clinical findings and surgical approaches and outcomes.

METHODOLOGY

A retrospective analysis of our data from 2010 to 2020 summarized our cases of true lambdoid synostosis. We have used the medical notes and the radiological findings from computed tomography scans to summarize a case series of isolated lambdoid synostosis.

RESULTS

Our case series demonstrated 7 patients with true isolated lambdoid craniosynostosis. In most cases surgical intervention in the form of posterior cranial vault remodeling utilizing a bandeau, based on occipital advancement techniques, has demonstrated the most consistently favorable aesthetic outcome.

CONCLUSIONS

Surgical referral to a craniofacial center should be sought early in difficult to diagnose cases. Although rare, surgical intervention is indicated to correct potentially increased intracranial pressure and to ameliorate cranial dyscrania.

Diagnosis and Management of Suture-Related Concerns of the Infant Skull

The cranial fontanelles and sutures have several benign variations, including most cases of "early" or "late" closure of the anterior fontanelle, bathrocephaly, overriding sutures, and benign metopic ridging. However, recognizing true craniosynostosis and referring the patient to a craniofacial specialist in a timely fashion are imperative, as minimally invasive options can be offered to most patients younger than 6 months of age. Gaining comfort with the physical examination of an infant with an abnormal head shape is best achieved through experience and pattern recognition and will frequently facilitate an accurate diagnosis without the need for ionizing radiation.

Intracranial Volume Not Correlated With Severity in Trigonocephaly

Objectives:

Severity of trigonocephaly varies and potentially affects intracranial volume (ICV) and intracranial pressure (ICP). The aim of this study is to measure ICV in trigonocephaly patients and compare it to normative data and correlate ICV with the severity of the skull deformity according to UCSQ (Utrecht Cranial Shape Quantifier).

Design:

Retrospective study.

Setting:

Primary craniofacial center.

Patients, Participants:

Nineteen preoperative patients with nonsyndromic trigonocephaly (age ≤12 months).

Intervention:

Intracranial volume was measured on preoperative computed tomography (CT) scans by manual segmentation (OsiriX Fondation). Utrecht Cranial Shape Quantifier was used to quantify the severity of the skull deformity. When present, papilledema as sign of elevated ICP was noted.

Main Outcome Measures(s):

Measured ICV was compared to Lichtenberg normative cranial volume growth curves, and Pearson correlation coefficient was used to correlate UCSQ with the ICV.

Results:

Mean age at CT scan was 6 months (2-11). Mean measured ICV was 842 mL (579-1124). Thirteen of h19 patients (11/15 boys and 2/4 girls) had an ICV between ±2 SD curves of Lichtenberg, 2 of 19 (1/15 boys and 1/4 girls) had an ICV less than −2 SD and 4 of 19 (3/15 boys and 1/4 girls) had an ICV greater than +2 SD. Mean UCSQ severity of trigonocephaly was 2.40 (−622.65 to 1279.75). Correlation between severity and ICV was negligible (r = −0.11). No papilledema was reported.

Conclusions:

Measured ICV was within normal ranges for trigonocephaly patients, in both mild and severe cases. No correlation was found between severity of trigonocephaly and ICV.

Complex Airway Management in Patients with Tracheal Cartilaginous Sleeves

OBJECTIVES/HYPOTHESIS

A tracheal cartilaginous sleeve (TCS) is a rare anomaly characterized by anterior fusion of tracheal cartilages. TCS is associated with syndromic craniosynostoses including Apert, Crouzon and Pfeiffer syndromes and FGFR2, FGFR3, and TWIST1 variants. This study presents a 30-year review of patients with syndromic craniosynostosis and TCS and describes diagnostic methods, genetic variants, surgical interventions, and long-term outcomes.

STUDY DESIGN

Retrospective, single-institution review.

METHODS

This review included patients with syndromic craniosynostosis and TCS treated at Seattle Children's Hospital from 1990 to 2020. Tracheostomy, genetic variants, and additional surgery were primary measures. Fisher's exact test compared need for tracheostomy in patients with proposed high-risk (FGFR2 p.W290 or FGFR2 p.C342) versus low-risk genetic variants.

RESULTS

Thirty patients with TCS were identified. Average age at diagnosis was 12 months (range 2-weeks to 7.9-years; standard deviation 19.8 months). Syndromes included Pfeiffer (37%), Apert (37%), and Crouzon (26%). Severe obstructive sleep apnea was present in 76% of patients. Tracheostomy was performed in 17 patients (57%); five were successfully decannulated. Additional interventions included adenotonsillectomy (57%), nasal (20%), laryngeal (17%), and craniofacial skeletal surgery (87%). All patients with Pfeiffer syndrome and FGFR2 p.W290C variants and 83% of patients with FGFR2 p.C342 variants required tracheostomy, differing from other variants (P = .02, odds ratio 33, 95% confidence interval 1.56-697.96). One patient (3%) died.

CONCLUSION

TCS contributes to multilevel airway obstruction in patients with syndromic craniosynostosis. Genetic testing in patients with FGFR2-related syndromic craniosynostoses may identify those at risk of TCS and facilitate early intervention. A better understanding of this patient population may foster individualized airway management strategies and improve outcomes.

LEVEL OF EVIDENCE

4 Laryngoscope, 2021.

Anthropometric changes in the skull base in children with sagittal craniosynostosis submitted to surgical correction

PURPOSE

Studies have examined the impact of fusion of the sagittal suture in the skull base while others have evaluated the growth of the skull base before and after surgery. This study aims to perform the anthropometric measures of the skull base in children with scaphocephaly to evaluate the influence of surgical repair in the remodeling of the skull base and anthropometric measures.

METHODS

Twenty-one children with diagnosis of scaphocephaly were operated between April 2007 and October 2008, and anthropometric measures at the skull base were performed before and after a year of surgery. The measures were the cranial index (CI), distance between the crista galli and tuberculum sellar (CG-TS), distance between the crista galli and the internal auditory meatus (CG-IAM), distance between the oval foramen (OF-OF), distance between the internal auditory meatus (IAM-IAM), the angle of the skull base (Â1), and the angle between the nasion, center of sella, and basion (Â2).

RESULTS

There was a normalization of the CI in all children, confirming an appropriate cranial remodeling. The CG-TS measure evaluated the anterior skull base, with proportional growth of 12.5%. The mediolateral growth was observed by the increase of OF-OF measures by 8.5% and IAM-IAM by 9.5%. The CG-TS measure grew by 7.2%. There was no statistical difference in the angles analyzed.

CONCLUSION

Surgical treatment of scaphocephaly led to remodeling of the skull base, confirmed by the changes of anthropometric measures taken before and after a year of surgery.

Neuro-Ophthalmological Manifestations of Craniosynostosis: Current Perspectives

Craniosynostosis, a premature fusion of cranial sutures that can be isolated or syndromic, is a congenital defect with a broad, multisystem clinical spectrum. The visual pathway is prone to derangements in patients with craniosynostosis, particularly in syndromic cases, and there is a risk for permanent vision loss when ocular disease complications are not identified and properly treated early in life. Extensive advancements have been made in our understanding of the etiologies underlying vision loss in craniosynostosis over the last 20 years. Children with craniosynostosis are susceptible to interruptions in visual input arising from strabismus, refractive errors, and corneal damage; any of these aberrations can result in understimulation of the visual cortex during childhood neurodevelopment and permanent amblyopia. Elevated intracranial pressure resulting from abnormal cranial shape or volume can lead to papilledema and, ultimately, optic atrophy and vision loss. A pediatric ophthalmologist is a crucial component of the multidisciplinary care team that should be involved in the care of craniosynostosis patients and consistent ophthalmologic follow-up can help minimize the risk to vision posed by such entities as papilledema and amblyopia. This article aims to review the current understanding of neuro-ophthalmological manifestations in craniosynostosis and explore diagnostic and management considerations for the ophthalmologist taking care of these patients.

Cranial Fossa Volume and Morphology Development in Apert Syndrome

BACKGROUND

Apert syndrome causes normal or enlarged intracranial volume overall as patients grow. This study aimed to trace the segmental anterior, middle, and posterior cranial fossae volume and structural morphology in these patients, to help discern a more focused and individualized surgical treatment plan for patients with Apert syndrome.

METHODS

This study included 82 preoperative computed tomographic scans (Apert, n = 32; control, n = 50) divided into five age-related subgroups. The scans were measured using image processing and three-dimensional modeling software.

RESULTS

The middle cranial fossa volume was increased and was the earliest change noted. It was increased by 45 percent (p = 0.023) compared with controls before 6 months of age and remained increased into adulthood (161 percent, p = 0.016), with gradually increasing severity. The anterior and posterior cranial fossae volumes also increased, by 35 percent (p = 0.032) and 39 percent (p = 0.007), respectively. Increased depth of cranial fossae contributed most to the increase in volumes of patients with Apert syndrome, with correlation coefficients of 0.799, 0.908, and 0.888 for anterior, middle, and posterior cranial fossa, respectively. The intracranial volume was increased 12 percent (p = 0.098) across the entire test age range (0 to 26 years old), but only had statistical significance during the age range of 6 to 18 years (22 percent, p = 0.001).

CONCLUSIONS

Malformation of the middle cranial fossa is an early, perhaps the initial, pivotal cranial morphologic change in Apert syndrome. Increased cranial fossae depth is an inherent characteristic of the maldevelopment. Normalization of cranial volume and circumference overall may not achieve a normal skull structure, as it does not correct regional craniocerebral disproportion.

Quantification of Head Shape and Cranioplasty Outcomes: Six-compartment Volume Method Applied to Sagittal Synostosis

Supplemental Digital Content is available in the text.

Background:

Premature fusion of the sagittal (midline) suture between 2 parietal bones is the most common form of craniosynostosis. Surgical correction is mandated to improve head shape and to decrease the risk of raised intracranial pressure. This study evaluated the utility of 3-dimensional (3D) imaging to quantify the volumetric changes of surgical correction. Currently there is no standardized method used to quantify the outcomes of surgery for craniosynostosis, with the cranial index (width: length ratio) being commonly used.

Methods:

A method for quantification of head shape using 3D imaging is described in which the cranium is divided up into 6 compartments and the volumes of 6 compartments are quantified and analyzed. The method is size invariant, meaning that it can be used to assess the long-term postoperative outcomes of patients through growth. The method is applied to a cohort of sagittal synostosis patients and a normal cohort, and is used to follow up a smaller group of synostotic patients 1, 2, and 3 years postoperatively.

Results:

Statistical analysis of the results shows that the 6-compartment volume quantification method is more accurate in separating normal from synostotic patient head shapes than the cranial index.

Conclusions:

Spring-mediated cranioplasty does not return head shape back to normal, but results in significant improvements in the first year following surgery compared with the preoperative sagittal synostosis head shape. 3D imaging can be a valuable tool in assessing the volumetric changes due to surgery and growth in craniosynstosis patients.

Intracranial Venous Hypertension in Craniosynostosis: Mechanistic Underpinnings and Therapeutic Implications

Patients with complex, multisutural, and syndromic craniosynostosis (CSO) frequently exhibit intracranial hypertension. The intracranial hypertension cannot be entirely attributed to the craniocephalic disproportion with calvarial restriction because cranial vault expansion has not consistently alleviated elevated intracranial pressure. Evidence has most strongly supported a multifactorial interaction, including venous hypertension along with other pathogenic processes. Patients with CSO exhibit marked venous anomalies, including stenosis of the jugular-sigmoid complex, transverse sinuses, and extensive transosseous venous collaterals. These abnormal intracranial-extracranial occipital venous collaterals might represent anomalous development, with persistence and subsequent enlargement of channels normally present in the fetus, either as a primary defect or as nonregression in response to failure of the development of the jugular-sigmoid complexes. It has been suggested by some investigators that venous hypertension in patients with CSO could be treated directly via jugular foraminoplasty, venous stenting, or jugular venous bypass, although these options are not in common clinical practice. Obstructive sleep apnea, occurring as a consequence of midface hypoplasia, can also contribute to intracranial hypertension in patients with syndromic CSO. Thus, correction of facial deformities, as well as posterior fossa decompression, could also play important roles in the treatment of intracranial hypertension. Determining the precise mechanistic underpinnings underlying intracranial hypertension in any given patient with CSO requires individualized evaluation and management.

Increases in Cranial Volume with Posterior Cranial Vault Distraction in 31 Consecutive Cases

BACKGROUND

Posterior cranial vault distraction (PCVD) is a technique widely used in surgical treatment of craniosynostosis when cranial expansion is required. It has proven to be safe and to allow a significant increase of intracranial volume.

OBJECTIVE

To evaluate increases in intracranial volume as a result of PCVD performed in Oulu Craniofacial center using 2 different methods based on 3-dimensional (3-D) photogrammetric imaging or plain skull radiographs.

METHODS

All children less than 16 yr of age who were treated by PCVD (n = 31) from 2009 to 2015 at the Oulu Craniofacial Center were included. All patients were followed at outpatient clinics with plain radiographs performed for follow-up. In 5 patients, additional 3-D photogrammetric imaging was done pre- and postoperatively.

RESULTS

The mean intracranial volume increase was 25.0%, ranging from 16.9% to 39.4%. In 5 patients, the increase in volume was calculated from the photogrammetric 3-D images comprising a mean of 17.4%. Volume calculations from cephalograms in the same patients gave a mean of 20.8%. Whether the distraction was a primary operation or patient had undergone previous cranioplasty did not influence the achieved volumetric results. There were no statistically significant differences in the distraction results between different diagnostic groups.

CONCLUSION

PCVD is an effective surgical method to increase intracranial volume in a variety of clinical entities. Volumetric results of this procedure could be easily evaluated using 3-D photogrammetric imaging or plane radiographs that expose the patients to only low ionizing radiation doses.

Endoscopy-assisted craniosynostosis surgery followed by helmet therapy

Background

Surgical methods to treat craniosynostosis have evolved from a simple strip craniectomy to a diverse spectrum of partial or complete cranial vault remodeling with excellent results but often with high comorbidity. Therefore, minimal invasive craniosynostosis surgery has been explored in the last few decades. The main goal of minimal invasive craniosynostosis surgery is to reduce the morbidity and invasiveness of classical surgical procedures, with equal long-term results, both functional as well as cosmetic.

Methods

To reach these goals, we adopted endoscopy-assisted craniosynostosis surgery (EACS) supplemented with helmet molding therapy in 2005.

Results

We present in detail our surgical technique used for scaphocephaly, trigonocephaly, plagiocephaly, complex multisutural, and syndromic cases of craniosynostosis.

Conclusions

We conclude that EACS with helmet therapy is a safe and suitable treatment option for any type of craniosynostosis, if performed at an early age, preferably around 3 months of age.

Reduced Intercarotid Artery Distance in Syndromic and Isolated Brachycephaly

INTRODUCTION

The morphology of the skull base can be altered in craniosynostoses. The objective of this study is to evaluate the reduced intercarotid artery distance in the lacerum segment in patients with syndromic and isolated brachycephaly.

MATERIALS AND METHODS

The distances between the inner walls of the carotid canal at the lacerum segment were measured on high-resolution CT scans in children with Crouzon (25), Pfeiffer (21), Apert (26), Saethre-Chotzen (7) syndromes, isolated bicoronal synostosis (9), and compared to an age-matched control group (30).

RESULTS

A significantly smaller mean distance between carotid canal walls was observed in Crouzon (11.1 ± 4.9 mm), Pfeiffer (9.6 ± 5.1 mm), Apert (12.3 ± 4.3 mm), Saethre-Chotzen (14.8 ± 3.0 mm) syndromes, and isolated bicoronal synostosis (14.9 ± 3.7 mm) as compared to the control group (19.7 ± 2.4 mm, P < 0.001, P < 0.001, P < 0.001, P = 0.005, and P = 0.002, respectively). There was no statistically significant difference in intercarotid canal distance among the Apert, Saethre-Chotzen and isolated bicoronal synostosis groups. Overall, the brachycephalic group showed reduced intercarotid canal distance comparing to controls (P < 0.001).

DISCUSSION AND CONCLUSIONS

There is significant reduction of the distance between carotid canals in brachycephalic patients. This distance is more significantly altered in FGFR-related brachycephaly syndromes (especially Crouzon and Pfeiffer syndromes), than Saethre-Chotzen syndrome (TWIST1 mutation) and isolated non-syndromic bicoronal synostosis. This study highlights the importance of FGFRs in shaping the skull base. Altered vascular course of the internal carotid arteries can have important implications in planning skull base surgery in brachycephalic patients.

Growth curves for intracranial volume in normal Asian children fortify management of craniosynostosis

BACKGROUND

Although the charting of normal intracranial volume (ICV) is fundamental for managing craniosynostosis, Asian norms in this regard are unknown. The purpose of this study was to establish a growth curve for ICVs in a large series of normal Asian children, providing reference values to guide corrective surgery.

METHODS

A total of 124 normal children (male, 63; female, 61) and 41 children diagnosed with craniosynostoses were analyzed. Patients aged 0-8 years presenting to the emergency room and subjected to computed tomography (CT) for head trauma served as the reference cohort. Axial CT head scan data were obtained from radiographic archives at Jichi Medical University. Imaging was done on a Siemens CT scanner (5-mm slice thickness), using a DICOM viewer to measure ICVs.

RESULTS

ICVs were plotted against age, and best-fit logarithmic curves for normal subjects were generated, without and with gender stratification. Male and female growth curves were similar in shape but diverged past the age of 1 year (male > female). ICVs of patients with craniosynostoses were plotted to male and female growth curves by disease subset, revealing the following: sagittal synostosis, near normal (or marginally larger); metopic synostosis, below normal; other non-syndromic synostoses (unilateral, bilateral, and lambdoidal) and Crouzon syndrome, near normal; Apert syndrome, above normal; and Pfeiffer syndrome, variable.

CONCLUSION

ICVs of early childhood were investigated in Asian subjects, creating growth curves that set criteria for timing, planning and goalsetting in surgical correction of craniosynostosis.

Surgical strategy for Apert syndrome: Retrospective study of developmental quotient and three-dimensional computerized tomography

There are many surgical techniques for craniosynostosis. However, the indications for and timing of surgery still remain unclarified. Most of the skull growth in craniosynostosis is completed in the first year, and the bone is strong enough to undergo distraction osteogenesis. However, previous reports showed that patients operated on before 1 year of age had better IQ than those operated later in life. This report aims to consider the best timing for cranial expansion and surgical strategy for Apert syndrome. From January 2002 to December 2011, 13 patients with Apert syndrome were operated on and were followed up for more than 5 years. Nine patients underwent operations before 1 year of age (early surgery group) and three patients underwent operations later in life (late surgery group). They underwent fronto-orbital advancement for primary surgery. We evaluated postoperative developmental quotient every year and cephalic index (CI) measured by three-dimensional computerized tomography (3D-CT) at the age over 5 years retrospectively. Eleven of 13 patients improved their developmental quotient scores, with no significant intergroup differences. The CI evaluation showed cases with remnant brachycephalic deformity in both groups. Two patients with remnant plagiocephalic deformities tend to have primary surgery early in life compared to the others. Thus the delay in primary surgery had little influence on psychological development. We conclude that the primary surgery can be delayed unless the intracranial pressure needs to be controlled. In addition, fronto-orbital advancement could not sufficiently improve the brachycephalic appearance, other procedures like posterior vault distraction might be better alternatives.

Lumbar Puncture Pressures During Childhood in 262 Children with Craniosynostosis

OBJECTIVE

The aim of this study was to analyze age-dependent lumbar puncture pressures (LPPs) measured in 262 children with craniosynostosis to provide information that assists in determining surgery.

METHODS

From 1 July 2005 to 30 June 2014, 262 children with craniosynostosis diagnosed at the Department of Neurosurgery, Ajou University Hospital, underwent LPP measurement. These children were compared with respect to age, gender, birth weight, head circumference at the time of birth, gestational age, LPP, and developmental assessments.

RESULTS

Changes in LPP in children with craniosynostosis according to age were y = -0.0007x(2) + 0.1327x + 21.678 in all patients overall, y = -0.0003x(2) + 0.1166x + 21.466 in children with single-suture craniosynostosis, and y = -0.002x(2) + 0.248x + 22.55 in patients with multiple and syndromic craniosynostosis, indicating a steady and slow increase from birth until the age of 4 years. Also, 59.9% of the 262 children had LPP greater than 20 cm H2O, but when the LPP cutoff level was adjusted for age, this proportion was 99.2%; the new criterion after the adjusted LPP cutoff level showed that for those with increased LPP, the proportion was 63.4%.

CONCLUSIONS

We suggest that LPP increases slowly with age in children with craniosynostosis, increased LPP rates in children with craniosynostosis were higher than previously expected, and the new cutoff level criterion that adjusts for age may be more helpful than a fixed cutoff level for all ages.

Physiological Changes and Clinical Implications of Syndromic Craniosynostosis

Syndromic craniosynostosis has severe cranial stenosis and deformity, combined with hypoplastic maxillary bone and other developmental skeletal lesions. Among these various lesions, upper air way obstruction by hypoplastic maxillary bone could be the first life-threatening condition after birth. Aggressive cranial vault expansion for severely deformed cranial vaults due to multiple synostoses is necessary even in infancy, to normalize the intracranial pressure. Fronto-orbital advancement (FOA) is recommended for patients with hypoplastic anterior part of cranium induced by bicoronal and/or metopic synostoses, and posterior cranial vault expansion is recommended for those with flattening of the posterior part of the cranium by lambdoid synostosis. Although sufficient spontaneous reshaping of the cranium can be expected by expansive cranioplasty, keeping the cranial bone flap expanded sufficiently is often difficult when the initial expansion is performed during infancy. So far distraction osteogenesis (DO) is the only method to make it possible and to provide low rates of re-expansion of the cranial vault. DO is quite beneficial for both FOA and posterior cranial vault expansion, compared with the conventional methods. Associated hydrocephalus and chronic tonsillar herniation due to lambdoid synostosis can be surgically treatable. Abnormal venous drainages from the intracranial space and air way obstruction should be always considered at any surgical procedures. Neurosurgeons have to know well about the managements not only of the deformed cranial vault and the associated brain lesions but also of other multiple skeletal lesions associated with syndromic craniosynostosis, to improve treatment outcome.

Raised intracranial pressure in Crouzon syndrome: incidence, causes, and management

OBJECT Patients with Crouzon syndrome (CS) are at risk for developing raised intracranial pressure (ICP), which has the potential to impair both vision and neurocognitive development. For this reason, some experts recommend early prophylactic cranial vault expansion on the basis that if ICP is not currently raised, it is likely to become so. The aim of this study was to examine the justification for such a policy. This was done by analyzing the incidence, causes, and subsequent risk of recurrence in a series of patients with CS, in whom raised ICP was treated only after it had been diagnosed. METHODS This study was a retrospective review of the medical records and imaging data of patients with a clinical diagnosis of CS. RESULTS There were 49 patients in the study, of whom 30 (61.2%) developed at least 1 episode of raised ICP. First episodes occurred at an average age of 1.42 years and were attributable to craniocerebral disproportion/venous hypertension (19 patients), hydrocephalus (8 patients), and airway obstruction (3 patients). They were managed, respectively, by vault expansion, ventriculoperitoneal shunt insertion, and airway improvement. Fourteen of the 30 patients developed a second episode of raised ICP an average of 1.42 years after treatment for their initial episode, and 3 patients developed a third episode an average of 3.15 years after that. Causes of subsequent episodes of raised ICP often differed from previous episodes and required different management. Patients who were < 1 year old when the first episode was diagnosed were at increased risk of recurrence. CONCLUSIONS Although the incidence of raised ICP in CS is high, it did not occur in nearly 40% of children during the course of this study. The several possible causes of CS require different management and may vary from episode to episode. The authors recommend an expectant policy toward these children with careful clinical, ophthalmological, respiratory, and radiological monitoring for raised ICP, reserving intervention for when it has been detected and the appropriate treatment can be initiated.

Plagiocephaly due to Frontosphenoidal Suture Synostosis: Report of 2 Cases and Literature Review

BACKGROUND/AIMS

The most common cause of anterior plagiocephaly is the fusion of the unilateral coronal suture. In some rare cases, however, the fusion of the frontosphenoidal suture may lead to a resembling pattern with specific clinical and radiological features. The aim of the present study is to further enlighten this entity as it is misdiagnosed most of the time.

METHODS

A report of 2 cases of plagiocephaly due to frontosphenoidal synostosis with a review of the literature.

RESULTS

One female and one male baby were identified. The mean age at presentation was 11.5 months (range: 1-22). Head circumference was normal in each patient. The two fusions were on the left side. Unilateral frontal flattening and recession of the supraorbital rim were the most important physical findings. Computed tomography confirmed the patency of the frontoparietal suture and the closure of the frontosphenoidal suture. Fronto-orbital advancement was performed in both cases with good cosmetic outcome.

CONCLUSION

Frontosphenoidal synostosis should be suspected and carefully searched when dealing with plagiocephaly with patent coronal suture. Good outcome requires a prompt diagnosis and early correction.

Effects of open and endoscopic surgery on skull growth and calvarial vault volumes in sagittal synostosis

BACKGROUND

There have been conflicting reports on how sagittal synostosis affects cranial vault volume (CVV) and which surgical approach best normalizes skull volume. In this study, we compared CVV and cranial index (CI) of children with sagittal synostosis (before and after surgery) with those of control subjects. We also compared the effect of repair type on surgical outcome.

METHODS

Computed tomography scans of 32 children with sagittal synostosis and 61 age- and sex-matched control subjects were evaluated using previously validated segmentation software for CVV and CI. Sixteen cases underwent open surgery, and 16 underwent endoscopic surgery. Twenty-seven cases had both preoperative and postoperative scans.

RESULTS

Age of subjects at computed tomography scan ranged from 1 to 9 months preoperatively and 15 to 25 months postoperatively. Mean age difference between cases and matched control subjects was 5 days. The mean CVV of cases preoperatively was nonsignificantly (17 mL) smaller than that of control subjects (P = 0.51). The mean CVV of postoperative children was nonsignificantly (24 mL) larger than that of control subjects (P = 0.51). Adjusting for age and sex, there was no significant difference in CVV between open and endoscopic cases postoperatively (β = 48 mL, P = 0.31). The mean CI increased 12% in both groups. There was no significant difference in mean postoperative CI (P = 0.18) between the 2 groups.

CONCLUSIONS

Preoperatively, children with sagittal synostosis have no significant difference in CVV compared with control subjects. Type of surgery does not seem to affect CI and CVV 1 year postoperatively. Both open and endoscopic procedures result in CVVs similar to control subjects.

Venous hypertension in syndromic and complex craniosynostosis: the abnormal anatomy of the jugular foramen and collaterals

Why craniosynostosis patients develop elevated intracranial pressure (ICP) is still a mystery. Our aim was to investigate jugular foramen size and its relation to venous hypertension and elevated ICP. Secondly, we evaluated whether occipital collateral veins develop as a compensatory mechanism for elevated ICP. We conducted a prospective study in 41 children with craniosynostosis who underwent a 3D-CT-angiography. We evaluated the anatomical course of the jugular vein, the diameter of the jugular foramen and the relation to the presence of papilledema. Additionally, we studied the anatomical variations of the cerebral venous drainage system. The diameter of the jugular foramen was significantly smaller in our patients. Abnormal venous collaterals were most often observed in patients with Apert, Crouzon-Pfeiffer and Saethre-Chotzen syndrome, even in children under two years of age. There was no significant difference in the number of collateral veins in patients with or without papilledema. Collaterals appear to reflect an inborn abnormality of the venous system, rather than a compensating mechanism for elevated ICP. This study confirms the presence of jugular foraminal narrowing in craniosynostosis patients and an abnormal venous system, which may predispose to elevated ICP.

LEVEL OF EVIDENCE

Diagnostic II.

Posterior cranial vault expansion using distraction osteogenesis

PURPOSE

Posterior vault expansion using distraction osteogenesis has become a vital instrument in our institution, particularly as a first-line treatment in syndromic craniosynostosis. In this review, we highlight the several advantages, diverse utility, and technicalities of the operative procedure.

METHODS

A review of the literature and explanation of the technical details of the procedures were described in this manuscript.

RESULTS/CONCLUSION

Posterior cranial vault distraction offers several benefits over traditional expansion procedures.

Posterior cranial vault expansion in the treatment of craniosynostosis. Comparison of current techniques

INTRODUCTION

Surgical procedures which aim at expanding the posterior cranial vault have come to play an increasingly important role in the treatment of syndromic craniosynostosis. The posterior cranial vault may be expanded by formal cranioplasty or by less invasive methods based on gradual posterior cranial vault expansion or distraction. These procedures share the common goals to prevent intracranial hypertension and progression toward turricephaly by effectively increasing the intracranial volume. They also reduce any local brain compression within the posterior cranial fossa.

PATIENTS AND METHODS

This review describes the various techniques available for less invasive and gradual posterior cranial vault expansion and their rationale based on our experience on the last 40 cases. Volumetric data for three different surgical techniques have been compared (two cases of posterior cranial vault expansion by free-floating parieto-occipital bone flap, two with springs, and two with internal distractors). The volumetric analysis showed an expansion of 13 and 24 % for the free posterior flap, 18 and 25 % for the translambdoid springs, and 22 and 29 % for the distractors.

DISCUSSION

Although these figures are not strictly comparable, our data suggest that these three techniques offer a potential for a significant increase in skull volume. The indications for such procedures must, however, be tailored according to the age and condition of the single patient.

Isolated sagittal craniosynostosis: definition, classification, and surgical indications

Sagittal craniosynostosis (SC) remains the most common type of synostosis, accounting for about a half of all forms. It would result from a mesenchymal disorder involving the intramembranous ossification of the sagittal suture and leading to its early fusion. No specific data on the etiologic factors are currently available. The premature ossification of the sagittal suture can result in three main types of SC, according to the different segment prevalently involved: anterior, posterior, and complete SC. The diagnosis is easily obtained by clinical examination. However, a radiological work up (3D CT scan) may be necessary to rule out hidden venous or cranial anomalies possibly associated with most severe cases, or for the surgical planning. The most common indication for surgery is the improvement of the cosmetic appearance of the skull, since a cranial deformation may have a significant psychological impact on affected subjects. To relieve from raised intracranial pressure is a further indication to surgery. Although an increased intracranial pressure can be demonstrated in a minority of affected children at diagnosis, indeed, it can present later (usually after the second/third year of life) with chronic symptoms. The role of surgery in the preservation of cognitive functions in scaphocephalic patients does not seem to be relevant, since minor anomalies of the cerebral development associated with SC would occur independently from the cranial shape. On the other hand, the surgical correction may show a protective effect on some visual skills, like the ability to fix and follow, and the fixation shift.

Feature-invariant image registration method for quantification of surgical outcomes in patients with craniosynostosis: a preliminary study

Craniosynostosis consists of a premature fusion of the sutures in an infant skull that restricts skull and brain growth. During the last decades, there has been a rapid increase of fundamentally diverse surgical treatment methods. At present, the surgical outcome has been assessed using global variables such as cephalic index, head circumference, and intracranial volume. However, these variables have failed in describing the local deformations and morphological changes that may have a role in the neurologic disorders observed in the patients. This report describes a rigid image registration-based method to evaluate outcomes of craniosynostosis surgical treatments, local quantification of head growth, and indirect intracranial volume change measurements. The developed semiautomatic analysis method was applied to computed tomography data sets of a 5-month-old boy with sagittal craniosynostosis who underwent expansion of the posterior skull with cranioplasty. Quantification of the local changes between pre- and postoperative images was quantified by mapping the minimum distance of individual points from the preoperative to the postoperative surface meshes, and indirect intracranial volume changes were estimated. The proposed methodology can provide the surgeon a tool for the quantitative evaluation of surgical procedures and detection of abnormalities of the infant skull and its development.

Visual field loss in children with craniosynostosis

AIMS

To identify visual field deficits in a group of children with syndromic craniosynostosis.

METHODS

Kinetic visual field examination and visual evoked potentials (VEPs) were recorded in 16 children with syndromic craniosynostosis as part of their ophthalmic evaluation. VEPs were analyzed for inter-hemispheric asymmetries and component amplitude and latency, while visual fields were analyzed both qualitatively and quantitatively.

RESULTS

All children with craniosynostosis were found to have visual field deficits compared to controls. In the Crouzon group, deficits tended to involve the nasal field, while infero-nasal field deficits were the most consistent finding in children with Apert syndrome. Children with Pfeiffer's demonstrated the greatest deficits, with severe constrictions affecting the whole visual field. VEPs were asymmetrical in four cases while the P100 component was subnormal in ten of the 16 patients for either amplitude and/or latency.

CONCLUSION

Although we may speculate about the mechanisms that cause visual field deficits, we currently are unable to explain the reason for the differing types and extent of visual field loss in the different syndromic groups. We can conclude that the visual field deficits do indicate previous or ongoing visual dysfunction that cannot be monitored employing central vision tests alone.

Postoperative evaluation of surgery for craniosynostosis based on image registration techniques

Craniosynostosis consists of a premature fusion of the sutures in an infant skull, which restricts the skull and brain growth. During the last decades there has been a rapid increase of fundamentally diverse surgical treatment methods. At present, the surgical outcome has been assessed using global variables such as cephalic index, head circumerence and intracranial volume. However, the variables have failed in describing the local deformations and morphological changes, which are proposed to more likely induce neurological disorders.

Intracranial volume and whole brain volume in infants with unicoronal craniosynostosis

OBJECTIVE

Craniosynostosis has been hypothesized to result in alterations of the brain and cerebral blood flow due to reduced intracranial volume, potentially leading to cognitive deficits. In this study we test the hypothesis that intracranial volume and whole brain volume in infants with unilateral coronal synostosis differs from those in unaffected infants.

DESIGN

Our study sample consists of magnetic resonance images acquired from 7- to 72-week-old infants with right unilateral coronal synostosis prior to surgery (n  =  10) and age-matched unaffected infants (n  =  10). We used Analyze 9.0 software to collect three cranial volume measurements. We used nonparametric tests to determine whether the three measures differ between the two groups. Correlations were calculated between age and the three volume measures in each group to determine whether the growth trajectory of the measurements differ between children with right unicoronal synostosis and unaffected infants.

RESULTS

Our results show that the three volume measurements are not reduced in infants with right unicoronal synostosis relative to unaffected children. Correlation analyses between age and various volume measures show similar correlations in infants with right unicoronal synostosis compared with unaffected children.

CONCLUSIONS

Our results show that the relationship between brain size and intracranial size in infants with right unicoronal synostosis is similar to that in unaffected children, suggesting that reduced intracranial volume is not responsible for alterations of the brain in craniosynostosis.

Frontosphenoidal synostosis: a rare cause of unilateral anterior plagiocephaly

INTRODUCTION

When a child walks in the clinic with a unilateral frontal flattening, it is usually associated in our minds with unilateral coronal synostosis. While the latter might be the most common cause of anterior plagiocephaly, it is not the only one. A patent coronal suture will force us to consider other etiologies, such as deformational plagiocephaly, or synostosis of another suture. To understand the mechanisms underlying this malformation, the development and growth of the skull base must be considered.

MATERIALS AND METHODS

There have been few reports in the literature of isolated frontosphenoidal suture fusion, and we would like to report a series of five cases, as the recognition of this entity is important for its treatment.

CONCLUSION

Frontosphenoidal synostosis must be searched in the absence of a coronal synostosis in a child with anterior unilateral plagiocephaly, and treated surgically.