Raised Intracranial Pressure Is Frequent in Untreated Nonsyndromic Unicoronal Synostosis and Does Not Correlate with Severity of Phenotypic Features:

Intraoperative Intracranial Pressure Changes in Children With Craniosynostosis Undergoing Endoscopic-Assisted Strip Craniectomy

BACKGROUND AND OBJECTIVES

Craniosynostosis can lead to progressive cranial and skull base deformities and can be associated with increased intracranial pressure (ICP), ophthalmological manifestations, behavioral changes, and developmental delay. Most published data on the incidence of elevated ICP include older children undergoing open surgical correction. Endoscopic-assisted release of fused sutures with postoperative helmet therapy is an established method for managing craniosynostosis presenting at an early age; however, the immediate effect of this approach on ICP in a young cohort has not been previously reported.

METHODS

Prospective data on 52 children undergoing endoscopic-assisted release of stenosed cranial sutures were included. Individuals were excluded if they underwent open correction or had previous cranial surgery. Individuals underwent a standardized endoscopic approach for each suture type. ICP was measured using an intraparenchymal sensor both before creation of the neosuture and after complete release of the stenosed suture. An ICP reading of >10 mm Hg was considered elevated.

RESULTS

The mean age was 5.3 months, range 1 to 32 months, and 94% was younger than 12 months. The mean opening pressure was 12.7 mm Hg, and the mean closing pressure was 2.9 mm Hg. Opening ICP ≥10 mm Hg was present in 58%, ≥15 mm Hg was present in 31%, and ≥20 mm Hg was present in 23%. No patient had an ICP above 10 mm Hg at closing. The mean percentage change in ICP among all craniosynostosis cases was a 64% decrease. Optic disk swelling was identified in 28 children preoperatively and improved in 22 children at follow-up.

CONCLUSION

Elevated ICP may occur in infants with craniosynostosis at higher rates than previously reported. Endoscopic-assisted craniectomy has an immediate effect on lowering ICP and improving postoperative ophthalmological findings.

Surgical Outcomes in Unicoronal Synostosis-A 23-Year Experience From a Single Supraregional Craniofacial Unit

Unicoronal synostosis is a rare condition leading to anterior plagiocephaly with facial scoliosis and deformation of the anterior cranial fossa. Fronto-orbital advancement and remodelling (FOAR) is the standard of care for management, aiming to normalise the brow shape and position while ameliorating the risk of raised intracranial pressure (ICP) throughout childhood. Published long-term surgical outcome data for unicoronal synostosis is lacking. The authors present our series of 151 cases of FOAR for unicoronal synostosis between January 2000 and January 2023. The average age at surgery was 22.7 months, with an average follow-up of 87 months. Ninety-six patients (66.2%) had no comorbidity. Nineteen (13.1%) had named genetic or chromosomal disorders. There was a 33.1% dural tear rate with no related postoperative CSF leak. Ninety-three patients (67.8%) had a blood transfusion with average donor exposure <1. The total early complication rate was 8.6% most commonly infection and wound dehiscence at 3.4% and 2.8%, respectively. The most common late complication was temporal recession in 30 (20.1%) patients and 3 of these patients required revision surgery. None of our patients required investigation for, or treatment of, raised ICP after the primary surgery. There were no life-threatening complications or mortalities. The authors compare our results to a previous publication on trigonocephaly patients and other available published data. The authors present our recommendations, which include support for a supraregionalized service that encompasses high-volume workload and multidisciplinary care.

The Current State of Non-Invasive Measurement of Intracranial Pressure in Patients with Craniosynostosis: A Systematic Review

Introduction:

Despite being invasive, direct measurements remain the gold standard to measure intra-cranial pressure (ICP) in patients with craniosynostosis. However, there has been persistent effort to develop non-invasive modalities to measure ICP, possibly avoiding some of the risks of direct measurements. Here, we conduct a systematic review of the evidence behind various non-invasive modalities to monitor ICP in patients with craniosynostosis.

Methods:

A systematic review was conducted using PubMed, Cochrane, and Web of Science databases to identify studies describing the use of non-invasive ICP measurements in patients with craniosynostosis. Studies were included if they assessed a non-invasive method of ICP monitoring against a direct/invasive ICP monitoring technique in patients with craniosynostosis. Non-English and non-human studies were excluded.

Results:

A total of 735 studies were screened, of which 52 were included in the study. Nine methods of non-invasive ICP measurement were identified, with varying sensitivities and specificities in detecting elevated ICP. Specifically, optical coherence tomography (OCT), and ocular ultrasonography demonstrated ability to accurately measure ICP when compared to direct measurements.

Conclusion:

Here, we present the first systemic-review of the current literature surrounding non-invasive modalities to measure ICP in patients with craniosynostosis. While direct measurement remains the gold-standard, multiple reviewed modalities have shown promise in accurately measuring ICP. Of these, OCT has the most rigorous evidence supporting its use. Ocular sonography has also shown promise, albeit without as robust evidence supporting its use. Regardless, further investigation is required before any modality is able to obviate the need for invasive, direct measurements.

Associated Risk Factors for Extended Length of Stay Following Cranial Vault Remodeling for Craniosynostosis: Analysis of the 2012 to 2021 NSQIP-Pediatric Database

OBJECTIVES

The aim of this study was to identify the factors associated with extended length of stay (LOS) for pediatric patients with craniosynostosis undergoing cranial vault remodeling (CVR).

METHODS

A retrospective cohort study was performed using the 2012 to 2021 American College of Surgeons National Surgical Quality Improvement Program-Pediatric database. Pediatric patients below 2 years old with craniosynostosis who underwent CVR were identified using Current Procedural Terminology and International Classification of Diseases-9/10 codes. Patients were dichotomized according to whether they encountered an extended postoperative hospital LOS, which was defined as LOS greater than the 75th percentile for the entire cohort (4 days). Patient demographics, comorbidities, intraoperative variables, postoperative adverse events, and health care resource utilization were assessed. Multivariate logistic regression analysis was utilized to identify predictors of prolonged LOS.

RESULTS

In our cohort of 9784 patients, 1312 (13.4%) experienced an extended LOS. The extended LOS cohort was significantly older than the normal LOS cohort (normal LOS: 225.1±141.8 d vs. extended LOS: 314.4±151.7 d, P <0.001) and had a smaller proportion of non-Hispanic white patients (normal LOS: 70.0% vs. extended LOS: 61.2%, P <0.001). Overall, comorbidities and adverse events were significantly higher in the extended LOS cohort than the normal LOS cohort. On multivariate logistic regression, independent associations of extended LOS included age, race and ethnicity, weight, American Society of Anesthesiologists classification, impaired cognitive status, structural pulmonary abnormalities, asthma, and neuromuscular disorders.

CONCLUSIONS

This study demonstrates that age, race, comorbidities, and perioperative complications contribute to extended LOS after CVR for craniosynostosis. Further investigations to further elucidate the risk factors of extended LOS is warranted to optimize patient outcomes.

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.

Long-term aesthetic and photogrammetric outcomes in non-syndromic unicoronal synostosis: comparison of fronto-orbital distraction osteogenesis and fronto-orbital advancement and remodeling

BACKGROUND

Fronto-orbital advancement and remodeling (FOAR) is among the most common surgical approaches for unicoronal craniosynostosis (UCS), although some data demonstrate failure to achieve long-term aesthetic normalcy, leading some to seek alternative treatment paradigms such as fronto-orbital distraction osteogenesis (FODO). This study compares long-term aesthetic outcomes of patients with UCS treated with FOAR and FODO.

METHODS

Twenty patients (four males) with non-syndromic UCS presenting to our institution and undergoing distraction were compared to a matched cohort of 20 patients (six males) undergoing FOAR. Clinical photographs and ImageJ were used to quantify periorbital anatomy including palpebral fissures, pupil-to-brow distance (PTB), and margin-reflex distance (MRD₁) in pixels. Whitaker classification was blindly assigned by craniofacial surgeons.

RESULTS

Photogrammetric analysis and Mann-Whitney U tests demonstrated significantly improved postoperative symmetry in distraction patients for palpebral width (p = 0.020), MRD₁ (p = 0.045), and canthal tilt (p = 0.010). Average Whitaker classification scores between FOAR (1.94) and distraction (1.79) cohorts were similar (p = 0.374).

CONCLUSIONS

UCS patients demonstrated significant postoperative improvements in periorbital symmetry, with distraction patients demonstrating superior results in palpebral width and canthal tilt. FOAR and FODO patients achieved similar Whitaker classification scores. These cohorts will be followed until craniofacial maturity prior to making any definitive conclusions.

Relating Metopic Craniosynostosis Severity to Intracranial Pressure

PURPOSE

A subset of patients with metopic craniosynostosis are noted to have elevated intracranial pressure (ICP). However, it is not known if the propensity for elevated ICP is influenced by the severity of metopic cranial dysmorphology.

METHODS

Children with nonsyndromic single-suture metopic synostosis were prospectively enrolled and underwent optical coherence tomography to measure optic nerve head morphology. Preoperative head computed tomography scans were assessed for endocranial bifrontal angle as well as scaled metopic synostosis severity score (MSS) and cranial morphology deviation score determined by CranioRate, an automated severity classifier.

RESULTS

Forty-seven subjects were enrolled between 2014 and 2019, at an average age of 8.5 months at preoperative computed tomography and 11.8 months at index procedure. Fourteen patients (29.7%) had elevated optical coherence tomography parameters suggestive of elevated ICP at the time of surgery. Ten patients (21.3%) had been diagnosed with developmental delay, eight of whom demonstrated elevated ICP. There were no significant associations between measures of metopic severity and ICP. Metopic synostosis severity score and endocranial bifrontal angle were inversely correlated, as expected (r=-0.545, P<0.001). A negative correlation was noted between MSS and formally diagnosed developmental delay (r=-0.387, P=0.008). Likewise, negative correlations between age at procedure and both MSS and cranial morphology deviation was observed (r=-0.573, P<0.001 and r=-0.312, P=0.025, respectively).

CONCLUSIONS

Increased metopic severity was not associated with elevated ICP at the time of surgery. Patients who underwent later surgical correction showed milder phenotypic dysmorphology with an increased incidence of developmental delay.

Elevated intracranial pressure with craniosynostosis: a multivariate model of age, syndromic status, and number of involved cranial sutures

OBJECTIVE

Children with multiple prematurely fused cranial sutures and those undergoing surgical correction later in life appear to experience worse neurocognitive outcomes, but it is unclear whether higher intracranial pressure (ICP) is implicated in this process. The purpose of this study was to elucidate the effect of age at intervention and number of involved cranial sutures on ICP, as well as to assess which cranial suture closure may be more associated with elevated ICP.

METHODS

The prospective craniofacial database at the authors' institution was queried for patients undergoing initial corrective surgery for craniosynostosis in whom intraoperative measurement of ICP was obtained prior to craniectomy. Age, involved sutures, and syndromic status were analyzed in the context of measured ICP by using multiple linear regression.

RESULTS

Fifty patients met the inclusion criteria. Age at procedure (p = 0.028, β = +0.060 mm Hg/month) and multiple-suture involvement (p = 0.010, β = +4.175 mm Hg if multisuture) were both significantly implicated in elevated ICP. The actual number of major sutures involved was significantly correlated to ICP (p = 0.001; β = +1.687 mm Hg/suture). Among patients with single-suture involvement, there was an overall significant difference of median ICP across the suture types (p = 0.008), with metopic having the lowest (12.5 mm Hg) and sagittal having the highest (16.0 mm Hg). Patients with multiple-suture involvement had significantly higher ICP (p = 0.003; 18.5 mm Hg). Patients with craniofacial syndromes were 79.3 times more likely to have multiple-suture involvement (p < 0.001). Corrective surgery for craniosynostosis demonstrated significant intraoperative reduction of elevated ICP (all p < 0.050).

CONCLUSIONS

Syndromic status, older age at intervention for craniosynostosis, and multiple premature fusion of cranial sutures were associated with significantly higher ICP.

Severity of Unilateral Coronal Synostosis Linked to Intracranial Volume

ABSTRACT

Severity of unilateral coronal synostosis (UCS) varies and can affect intracranial volume (ICV), and intracranial pressure. Correlation between ICV and severity according to Utrecht Cranial Shape Quantifier and presence of papilledema as sign of raised intracranial pressure is determined. The authors included patients with UCS (≤18 months). Intracranial volume was calculated on preoperative CT scans by manual segmentation (OsiriX [Fondation OsiriX, Geneva, Switzerland]). Calculated ICV was compared to Lichtenberg normative data for control patients. When present, papilledema was noted. Utrecht Cranial Shape Quantifier was used to quantify severity using the variables: asymmetry ratio of frontal peak and ratio of frontal peak gradient. Severity of UCS was correlated to ICV using Pearson correlation coefficient. Mean age at CT scan of patients with UCS was 7 months (1-18 months). Mean calculated ICV was 870.96 mL (617.31-1264.46 mL). All patients had ICV between ± 2 SD curves of Lichtenberg; 10 had an ICV between -1 SD and +1 SD. Majority of ICV in girls was at or larger than normative mean, in boys ICV was mostly lower than normative mean. Pearson correlation coefficient between severity of UCS and ICV was negligible (r = -0.28). Preoperative papilledema during fundoscopy was found in 4.5% (1/22; ICV 1003.88 mL; severe UCS). Therefore, severity of UCS does not correlate to ICV. Despite varying severity of UCS, ICV remains within normal ranges.

Intracranial pressure patterns in children with craniosynostosis utilizing optical coherence tomography

BACKGROUND

Better understanding the incidence and patterns of elevated intracranial pressure (ICP) in patients with craniosynostosis may facilitate more timely intervention to alter neurocognitive outcomes. Spectral-domain optical coherence tomography (OCT) of the retina can non-invasively diagnose elevated ICP, and has demonstrated high sensitivity and specificity among patients with craniosynostosis. This study sought to characterize patterns of elevated ICP among patients with craniosynostosis.

METHODS

Quantitative retinal parameters were prospectively assessed in both eyes of patients with craniosynostosis using spectral-domain OCT. Based on retinal OCT thresholds associated with elevated ICP (> 15 mmHg), subjects were assigned an OCT diagnosis of elevated or non-elevated ICP which was analyzed relative to clinical characteristics and craniosynostosis patterns.

RESULTS

Eighty subjects (aged 0.2-18 years) with craniosynostosis were enrolled; among these, 67 (84%) were nonsyndromic. OCT evaluation was performed at initial vault expansion in 56 (70%) patients. Among this subset, 27 (48%) patients had peri-papillary changes suggestive of elevated ICP, reflecting a 44% incidence in nonsyndromic and 83% in syndromic patients. The median age at initial vault expansion was higher among those with elevated ICP (11.1 months) than those without (7.8 months; p = 0.04.) Multi-suture synostosis was associated with changes consistent with elevated ICP in 9 (75%) patients compared with 18 (41%) with single suture synostosis (p = 0.05).

CONCLUSIONS

OCT of the retina produces a potentially sensitive indicator of ICP in craniosynostosis patients. Elevated ICP may be associated with number of involved sutures and older patient presentation, and refining appropriate "cutoffs" will be important as the technology becomes more widespread.

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.

Papilledema in unicoronal synostosis: a rare finding

OBJECTIVE

Unicoronal synostosis results in frontal plagiocephaly and is preferably treated before the patient is 1 year of age to prevent intracranial hypertension (ICH). However, data on the prevalence of ICH in these patients is currently lacking. This study aimed to establish the prevalence of preoperative and postoperative signs of ICH in a large cohort of patients with unicoronal synostosis and to test whether there is a correlation between papilledema and occipitofrontal head circumference (OFC) curve stagnation in unicoronal synostosis.

METHODS

The authors included all patients with unicoronal synostosis treated before 2 years of age at a single center between 2003 and 2013. The presence of ICH was evaluated by routine fundoscopy. The OFC growth curve was analyzed for deflection and in relationship to signs of ICH.

RESULTS

In total, 104 patients were included in this study, 84 (81%) of whom were considered to have nonsyndromic unicoronal synostosis. Preoperatively, none of the patients had papilledema as determined by fundoscopy (mean age at surgery 11 months). Postoperatively, 5% of patients with syndromic synostosis and 3% of those with nonsyndromic synostosis had papilledema, and this was confirmed by optical coherence tomography. Raised intracranial pressure was confirmed in 1 patient with syndromic unicoronal synostosis. Six of 78 patients had OFC stagnation, which was not significantly correlated to papilledema (p = 0.22). One child with syndromic unicoronal synostosis required repeated surgery for ICH (0.96%).

CONCLUSIONS

Papilledema was not found in patients with unicoronal synostosis when they underwent surgery before the age of 1 year and was also very rare during follow-up. There was no relationship between papilledema and OFC stagnation.

Practical Computed Tomography Scan Findings for Distinguishing Metopic Craniosynostosis from Metopic Ridging

Background:

Premature fusion of the metopic suture (ie, metopic craniosynostosis) can be difficult to discriminate from physiological closure of the metopic suture with ridging (MR). Yet, MCS is treated surgically, whereas MR is treated nonsurgically. Often, the diagnosis can be made by physical examination alone, but in difficult cases, a computed tomography (CT) scan can add additional diagnostic information.

Methods:

We de-identified, randomized, and analyzed the CT scans of patients with MCS (n = 52), MR (n = 20) and age-matched normative controls (n = 52) to identify specific findings helpful in distinguishing between MCS and MR. Four expert clinicians were blinded to the clinical diagnosis and assessed each CT for features of the orbits, frontal bones, and inner table of calvaria.

Results:

Although no single feature was diagnostic of MCS, we identified several signs that were correlated with MCS, MR, or controls. Features such as “posteriorly displaced frontal bone” and “frontal bone tangent to mid-orbit or medial” demonstrated higher correlation with MCS than MR and the addition of other features improves the accuracy of diagnosis as did inclusion of the interfrontal divergence angle.

Conclusion:

The presence of a closed metopic suture in addition to other CT scan findings may improve the accuracy of diagnosing MCS, MR, and normocephaly.

Proof of Concept Study for the Design, Manufacturing, and Testing of a Patient-Specific Shape Memory Device for Treatment of Unicoronal Craniosynostosis

Treatment of unicoronal craniosynostosis is a surgically challenging problem, due to the involvement of coronal suture and cranial base, with complex asymmetries of the calvarium and orbit. Several techniques for correction have been described, including surgical bony remodeling, early strip craniotomy with orthotic helmet remodeling and distraction. Current distraction devices provide unidirectional forces and have had very limited success. Nitinol is a shape memory alloy that can be programmed to the shape of a patient-specific anatomy by means of thermal treatment.In this work, a methodology to produce a nitinol patient-specific distractor is presented: computer tomography images of a 16-month-old patient with unicoronal craniosynostosis were processed to create a 3-dimensional model of his skull and define the ideal shape postsurgery. A mesh was produced from a nitinol sheet, formed to the ideal skull shape and heat treated to be malleable at room temperature. The mesh was afterward deformed to be attached to a rapid prototyped plastic skull, replica of the patient initial anatomy. The mesh/skull construct was placed in hot water to activate the mesh shape memory property: the deformed plastic skull was computed tomography scanned for comparison of its shape with the initial anatomy and with the desired shape, showing that the nitinol mesh had been able to distract the plastic skull to a shape close to the desired one.The shape-memory properties of nitinol allow for the design and production of patient-specific devices able to deliver complex, preprogrammable shape changes.

Evaluation of Optical Coherence Tomography to Detect Elevated Intracranial Pressure in Children

Importance

Detecting elevated intracranial pressure in children with subacute conditions, such as craniosynostosis or tumor, may enable timely intervention and prevent neurocognitive impairment, but conventional techniques are invasive and often equivocal. Elevated intracranial pressure leads to structural changes in the peripapillary retina. Spectral-domain (SD) optical coherence tomography (OCT) can noninvasively quantify retinal layers to a micron-level resolution.

Objective

To evaluate whether retinal measurements from OCT can serve as an effective surrogate for invasive intracranial pressure measurement.

Design, Setting, and Participants

This cross-sectional study included patients undergoing procedures at the Children's Hospital of Philadelphia from September 2014 to June 2015. Three groups of patients (n = 79) were prospectively enrolled from the Craniofacial Surgery clinic including patients with craniosynostosis (n = 40). The positive control cohort consisted of patients with hydrocephalus and suspected intracranial hypertension (n = 5), and the negative control cohort consisted of otherwise healthy patients undergoing a minor procedure (n = 34).

Main Outcomes and Measures

Spectral-domain OCT was performed preoperatively in all cohorts. Children with cranial pathology, but not negative control patients, underwent direct intraoperative intracranial pressure measurement. The primary outcome was the association between peripapillary retinal OCT parameters and directly measured elevated intracranial pressure.

Results

The mean (SD) age was 34.6 (45.2) months in the craniosynostosis cohort (33% female), 48.9 (83.8) months in the hydrocephalus and suspected intracranial hypertension cohort (60% female), and 59.7 (64.4) months in the healthy cohort (47% female). Intracranial pressure correlated with maximal retinal nerve fiber layer thickness (r = 0.60, P ≤ .001), maximal retinal thickness (r = 0.53, P ≤ .001), and maximal anterior retinal projection (r = 0.53, P = .003). Using cut points derived from the negative control patients, OCT parameters yielded 89% sensitivity (95% CI, 69%-97%) and 62% specificity (95% CI, 41%-79%) for detecting elevated intracranial pressure. The SD-OCT measures had high intereye agreement (intraclass correlation, 0.83-0.93) and high intragrader and intergrader agreement (intraclass correlation ≥0.94). Conventional clinical signs had low sensitivity (11%-42%) for detecting intracranial hypertension.

Conclusions and Relevance

Noninvasive quantitative measures of the peripapillary retinal structure by SD-OCT were correlated with invasively measured intracranial pressure. Optical coherence tomographic parameters showed promise as surrogate, noninvasive measures of intracranial pressure, outperforming other conventional clinical measures. Spectral-domain OCT of the peripapillary region has the potential to advance current treatment paradigms for elevated intracranial pressure in children.

Characterization of complications associated with open and endoscopic craniosynostosis surgery at a single institution

OBJECT The authors present a retrospective cohort study examining complications in patients undergoing surgery for craniosynostosis using both minimally invasive endoscopic and open approaches. METHODS Over the past 10 years, 295 nonsyndromic patients (140 undergoing endoscopic procedures and 155 undergoing open procedures) and 33 syndromic patients (endoscopic procedures in 10 and open procedures in 23) met the authors' criteria. Variables analyzed included age at surgery, presence of a preexisting CSF shunt, skin incision method, estimated blood loss, transfusions of packed red blood cells, use of intravenous steroids or tranexamic acid, intraoperative durotomies, procedure length, and length of hospital stay. Complications were classified as either surgically or medically related. RESULTS In the nonsyndromic endoscopic group, the authors experienced 3 (2.1%) surgical and 5 (3.6%) medical complications. In the nonsyndromic open group, there were 2 (1.3%) surgical and 7 (4.5%) medical complications. Intraoperative durotomies occurred in 5 (3.6%) endoscopic and 12 (7.8%) open cases, were repaired primarily, and did not result in reoperations for CSF leakage. Similar complication rates were seen in syndromic cases. There was no death or permanent morbidity. Additionally, endoscopic procedures were associated with significantly decreased estimated blood loss, transfusions, procedure length, and length of hospital stay compared with open procedures. CONCLUSIONS Rates of intraoperative durotomies and surgical and medical complications were comparable between endoscopic and open techniques. This is the largest direct comparison to date between endoscopic and open interventions for synostosis, and the results are in agreement with previous series that endoscopic surgery confers distinct advantages over open surgery in appropriate patient populations.

Craniosynostosis

Craniosynostosis is the premature fusion of one or more of the cranial sutures. About 8% of the patients have familial or syndromic forms of synostosis, and in the remainder it occurs as a spontaneous isolated defect. Familial craniosynostosis syndromes are typically transmitted as an autosomal dominant trait resulting in disruption of the fibroblast growth factor receptor pathway. Familiarity with the characteristic head shapes resulting from craniosynostosis allows bedside diagnosis and differentiation from positional plagiocephaly. Because of the risks associated with untreated craniosynostosis, surgical treatment is usually undertaken soon after diagnosis. Current surgical methods include open calvarial reconstruction, minimally invasive strip craniectomy with use of postoperative molding helmet, minimally invasive strip craniectomy with spring implantation, and cranial distraction. Early referral to a pediatric craniofacial center allows all treatment options to be explored.

Gain-of-Function Mutations in ZIC1 Are Associated with Coronal Craniosynostosis and Learning Disability

Human ZIC1 (zinc finger protein of cerebellum 1), one of five homologs of the Drosophila pair-rule gene odd-paired, encodes a transcription factor previously implicated in vertebrate brain development. Heterozygous deletions of ZIC1 and its nearby paralog ZIC4 on chromosome 3q25.1 are associated with Dandy-Walker malformation of the cerebellum, and loss of the orthologous Zic1 gene in the mouse causes cerebellar hypoplasia and vertebral defects. We describe individuals from five families with heterozygous mutations located in the final (third) exon of ZIC1 (encoding four nonsense and one missense change) who have a distinct phenotype in which severe craniosynostosis, specifically involving the coronal sutures, and variable learning disability are the most characteristic features. The location of the nonsense mutations predicts escape of mutant ZIC1 transcripts from nonsense-mediated decay, which was confirmed in a cell line from an affected individual. Both nonsense and missense mutations are associated with altered and/or enhanced expression of a target gene, engrailed-2, in a Xenopus embryo assay. Analysis of mouse embryos revealed a localized domain of Zic1 expression at embryonic days 11.5-12.5 in a region overlapping the supraorbital regulatory center, which patterns the coronal suture. We conclude that the human mutations uncover a previously unsuspected role for Zic1 in early cranial suture development, potentially by regulating engrailed 1, which was previously shown to be critical for positioning of the murine coronal suture. The diagnosis of a ZIC1 mutation has significant implications for prognosis and we recommend genetic testing when common causes of coronal synostosis have been excluded.

Evaluating Children With Metopic Craniosynostosis: The Cephalic Width-Intercoronal Distance Ratio

OBJECTIVE

To identify an additional objective measure to aid in the evaluation of children with isolated metopic craniosynostosis.

DESIGN

This is a retrospective study comparing specific computed tomography scan measurements between surgical and nonsurgical cohorts of children with isolated metopic craniosynostosis. Children were included if they were diagnosed with isolated metopic craniosynostosis and ultimately underwent computed tomography scan imaging as part of their evaluation. The subjects were placed in the surgical or nonsurgical cohorts on the basis of the final treatment recommendation after they completed a full multidisciplinary, multimodality evaluation. Comparisons were made with a control group of unaffected patients from our institutional trauma registry.

SETTING

Tertiary academic institution.

PATIENTS, PARTICIPANTS

The subjects are patients who had been previously evaluated in our clinic for isolated metopic craniosynostosis and received a computed tomography scan as part of their workup.

RESULTS

The average intercoronal distances were significantly different among all three groups (P < .002). The average cephalic width-intercoronal distance ratio for children who received a recommendation for surgery differed significantly from that of both the observation cohort and the control group (P < .001). However, the cephalic width-intercoronal distance ratio did not differ between the observation cohort and the control group (P = .927).

CONCLUSIONS

The cephalic width-intercoronal distance ratio may be an additional objective measurement to aid in the clinical evaluation of children with metopic craniosynostosis.

A critical evaluation of long-term aesthetic outcomes of fronto-orbital advancement and cranial vault remodeling in nonsyndromic unicoronal craniosynostosis

BACKGROUND

This study reports long-term aesthetic outcomes with fronto-orbital advancement and cranial vault remodeling in treating unicoronal synostosis over a 35-year period.

METHODS

Retrospective review was performed on patients with isolated unicoronal synostosis from 1977 to 2012. Demographic, preoperative phenotypic, and long-term aesthetic outcomes data were analyzed with chi-squared and Fisher's exact test for categorical data and Wilcoxon rank-sum and Kruskal-Wallis rank for continuous data.

RESULTS

A total of 238 patients were treated; 207 met inclusion criteria. None underwent secondary intervention for intracranial pressure. At definitive intervention, there 96 (55 percent) Whitaker class I patients, 11 (6 percent) class II, 62 (35 percent) class III, and six (3 percent) class IV. Nasal root deviation and occipital bossing each conferred an increased risk of Whitaker class III/IV [OR, 4.4 (1.4 to 13.9), p = 0.011; OR, 2.6 (1.0 to 6.8), p = 0.049]. Patients who underwent bilateral cranial vault remodeling with extended unilateral bandeau were less likely Whitaker class III/IV at latest follow-up compared with those undergoing strictly unilateral procedures [OR, 0.2 (0.1 to 0.7), p = 0.011]. Overcorrection resulted in decreased risk of temporal hollowing [OR, 0.3 (0.1 to 1.0), p = 0.05]. Patients with 5 years or more of follow-up were more likely to develop supraorbital retrusion [OR, 7.2 (2.2 to 23.4), p = 0.001] and temporal hollowing [OR, 3.7 (1.5 to 9.6), p = 0.006] and have Whitaker class III/IV outcomes [OR, 4.9 (1.8 to 12.8), p = 0.001].

CONCLUSION

Traditional fronto-orbital advancement and cranial vault remodeling appears to mitigate risk of intracranial pressure but may lead to aesthetic shortcomings as patients mature, namely fronto-orbital retrusion and temporal hollowing.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

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.

The preoperative incidence of raised intracranial pressure in nonsyndromic sagittal craniosynostosis is underestimated in the literature

OBJECT

The presence of raised intracranial pressure (ICP) in untreated nonsyndromic, isolated sagittal craniosynostosis (SC) is an important functional indication for surgery.

METHODS

A retrospective review was performed of all 284 patients presenting with SC to the Oxford Craniofacial Unit between 1995 and 2010.

RESULTS

Intraparenchymal ICP monitoring was performed in 39 children following a standard unit protocol. Monitoring of ICP was offered for all patients in whom nonoperative management was considered on the basis of minimal deformity or in cases in which parents were reluctant to agree to corrective surgery. These patients presented at an older age than the rest of the cohort (mean age 56 months), with marked scaphocephaly (16/39, 41%), mild scaphocephaly (11, 28%), or no scaphocephalic deformity (12, 31%). Raised ICP was found in 17 (44%) patients, with no significant difference in its incidence among the 3 different deformity types. Raised ICP was not predicted by the presence of symptoms of ICP or developmental delay or by ophthalmological or radiological findings.

CONCLUSIONS

The incidence of raised ICP in SC reported here is greater than that previously published in the literature. The lack of a reliable noninvasive method to identify individuals with elevated ICP in SC mandates consideration of intraparenchymal ICP monitoring in all patients for whom nonoperative management is contemplated.

Evidence-based medicine: Craniosynostosis

LEARNING OBJECTIVES

After studying this article, the participant should be able to: (1) Make the appropriate diagnosis for each of the single-sutural synostoses, based on the physical examination. (2) Explain the functional concerns associated with these synostoses and why surgical correction is indicated. (3) Distinguish between the different types of surgical corrections available, the timing for these various interventions, and in what ways these treatments achieve overall management objectives. (4) Identify the basic goals involved in caring for the syndromic synostoses.

SUMMARY

This article provides an overview of the diagnosis and management of infants with craniosynostosis. This review also incorporates some of the treatment philosophies followed at The Craniofacial Center in Dallas, but is not intended to be an exhaustive treatise on the subject. It is designed to serve as a reference point for further in-depth study by review of the reference articles presented. This information base is then used for self-assessment and benchmarking in parts of the Maintenance of Certification process of the American Board of Plastic Surgery.