Visual failure caused by raised intracranial pressure in craniosynostosis

Utility of Papilledema for Detection of Elevated Intracranial Pressure in Craniosynostosis

Papilledema is swelling of the optic disk due to fluid accumulation around the optic nerve and is commonly used to detect increased intracranial (ICP) in craniosynostosis. This study aimed to assess the prevalence and utility of papilledema detection in patients with single-suture, multi-suture, and syndromic craniosynostosis and the differences before and after surgical intervention. A retrospective review of ophthalmology examinations of patients diagnosed with craniosynostosis treated between 2008 and 2023 was performed. Demographics, diagnosis, and operative data were collected. A total of 1509 ophthalmology exams of 519 patients were reviewed. The overall rate of papilledema in patients with craniosynostosis was 2.12%. The single-suture and multi-suture involvement rates were 1.15% and 5.81%, respectively. Non-syndromic patients with preoperative and postoperative examinations had an overall rate of 3.13%. Most had single suture involvement, and the average age of papilledema examination was 72 months. Syndromic patients with preoperative and postoperative examinations had an overall rate of 17.65%. The majority had multiple suture involvement, and the average age of papilledema examination was 26 months. The overall papilledema detection rate was low in patients with craniosynostosis. Multi-suture involvement and syndromic diagnosis had increased rates of papilledema. The average age of diagnosis was in older children. Syndromic patients had papilledema examination at a younger age. The authors' findings support the concept that fundoscopic ophthalmologic examination will benefit patients with multi-suture involvement, an associated syndrome, and older age.

Late-Presenting Sagittal Craniosynostosis: An Update to a Standardized Treatment Protocol

BACKGROUND

The authors previously published their protocol to treat patients who present with sagittal craniosynostosis after the age of 1 year. The purpose of this article is to present a follow-up and update of this cohort to evaluate outcomes of their treatment protocol.

METHODS

Patients with isolated sagittal craniosynostosis who presented after the age of 1 year between July of 2013 and April of 2021 were included.

RESULTS

A total of 108 patients met inclusion criteria. The average age at presentation was 5.2 ± 3.4 years, and 79 patients (73.1%) were male. The indications for imaging were head shape (54.6%), headache (14.8%), trauma (9.3%), seizure (4.6%), papilledema (2.8%), and other (13.9%). Of the 108 patients, 12 (11.1%) underwent surgery following their initial consultation: five for papilledema, four for elevated intracranial pressure, two for severely scaphocephalic head shapes, and one for abnormal funduscopic findings. Two of these patients underwent additional reconstructive surgery, one for the recurrence of papilledema and headache and the other for progressive scaphocephaly. The average length of time between operations was 4.9 years. Of the 96 patients who were managed conservatively, four (4.2%) underwent surgery at an average of 1.2 ± 0.5 years later (average age, 4.4 ± 1.5 years) for brain growth restriction ( n = 2), aesthetic concerns ( n = 1), and refractory headaches ( n = 1). The average follow-up of all patients with craniofacial surgery was 2.7 ± 2.3 years (median, 2.1 years; interquartile range, 3.7 years).

CONCLUSIONS

Patients with late-presenting sagittal craniosynostosis require surgical correction less often than younger patients, likely because of milder phenotype. Few patients in the conservative treatment arm ultimately required surgery (4%).

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Ophthalmic Manifestations of Unilateral Coronal Synostosis

PURPOSE

To summarize the ophthalmic manifestations of unilateral coronal synostosis patients.

METHODS

We performed a literature search in the electronic database of PubMed, CENTRAL, Cochrane, and Ovid Medline guided by Preferred Reporting Items for Systematic Reviews and Meta-Analysis Statement for studies evaluating ophthalmic manifestations of unilateral coronal synostosis.

RESULTS

Unilateral coronal synostosis, also called unicoronal synostosis, may be mistaken for deformational plagiocephaly, an asymmetric skull flattening common in newborns. Characteristic facial features, however, distinguish the two. Ophthalmic manifestations of unilateral coronal synostosis include a "harlequin deformity", anisometropic astigmatism, strabismus, amblyopia, and significant orbital asymmetry. The astigmatism is greater on the side opposite the fused coronal suture. Optic neuropathy is uncommon unless unilateral coronal synostosis accompanies more complex multi-suture craniosynostosis. In many cases, surgical intervention is recommended; without intervention, skull asymmetry and ophthalmic disorders tend to worsen with time. Unilateral coronal synostosis can be managed by early endoscopic stripping of the fused suture and helmeting through a year of age or by fronto-orbital-advancement at approximately 1 year of age. Several studies have demonstrated that anisometropic astigmatism, amblyopia, and severity of strabismus are significantly lower after earlier intervention with endoscopic strip craniectomy and helmeting compared to treatment by fronto-orbital-advancement. It remains unknown whether the earlier timing or the nature of the procedure is responsible for the improved outcomes. As endoscopic strip craniectomy can only be performed in the first few months of life, early recognition of the facial, orbital, eyelid, and ophthalmic characteristics by consultant ophthalmologists enables expeditious referral and optimized ophthalmic outcomes.

CONCLUSION

Timely identification of craniofacial and ophthalmic manifestations of infants with unilateral coronal synostosis is important. Early recognition and prompt endoscopic treatment appears to optimize ocular outcomes.

Systematic Review of the Clinical and Experimental Research Assessing the Effects of Craniosynostosis on the Brain

Although neurocognitive impairment has been considered as the main argument for the surgical treatment of craniosynostosis (CS), recent studies reported subtle deficits in neurological function even in operated patients. However, the cause of these deficits remains poorly understood. This systematic review sought to examine the impact of CS on the brain microstructure, mainly on functional connectivity, and comprehensively summarize the clinical and experimental research available on this topic. A systematic review was performed considering the publications of the last 20 years in PubMed and Web of Science, including relevant human and animal studies of the types of brain-microstructure disturbances in CS. Among the 560 papers identified, 11 were selected for analysis. Seven of those were conducted in humans and 4 in animal models. Resting-state functional magnetic resonance imaging, task-based magnetic resonance imaging, and diffusion tensor imaging were the main instruments used to investigate brain connectivity in humans. The main findings were increased connectivity of the posterior segment of cingulum gyri, reduced interconnectivity of the frontal lobes, and reduced diffusivity on diffusion tensor imaging, which were associated with hyperactivity behaviors and poorer performance on neurocognitive tests. Conversely, despite the lack of evidence of brain dysfunction in animal studies, they reported a tendency toward the development of hyperactive behaviors and impairment of neurocognitive function. Skull restriction caused by CS apparently chronically increases the intracranial pressure and produces white matter injuries. The current evidence supports the contention that an early surgical approach could minimize brain-connectivity impairment in this context.

Optic Nerve Atrophy in Syndromic Craniosynostosis

BACKGROUND

Numerous children born with syndromic craniosynostosis will develop visual impairments. Based on the hypothesis that elevations in intracranial pressure might have greater impacts on vision than development, this review sought to ascertain the prevalence of optic nerve atrophy in syndromic craniosynostosis and to look for potential predictive factors.

METHODS

A retrospective chart review of all children with syndromic craniosynostosis treated at a single center.

RESULTS

Of 442 patients with syndromic craniosynostosis, complete ophthalmologic records were available for 253. Although no instances of optic nerve atrophy were noted among those with Saethre-Chotzen or Muenke syndromes, an overall 14.7% prevalence was noted among those with Apert (7.8%), Crouzon (27.9%), and Pfeiffer syndromes (23.1%), with initial diagnoses occurring at a mean age of 10 years. The presence of a Chiari malformation was found to significantly correlate with the subsequent diagnosis of optic nerve atrophy (Odds ratio 3.544, p = 0.002); however, the timing of the first cranial vault procedure, presence of a venticuloperitoneal shunt, degree of brachycephaly, number of vault expansions, and diagnosis of sleep apnea, did not show significant associations.

CONCLUSIONS

A substantial percentage of children with Apert, Crouzon, and Pfeiffer syndrome were found to develop optic nerve atrophy, with a prevalence likely to trend higher with longer follow up. Chiari malformations were the only significant potential predictor for optic nerve atrophy. With the goal of preventing visual losses, more frequent monitoring for raised intracranial pressure with ophthalmologic evaluations and MRI measurements of optic nerve sheath diameters should be considered.

Prevalence of Ocular Anomalies in Craniosynostosis: A Systematic Review and Meta-Analysis

Background: The aim of this study was to describe the ophthalmic abnormalities and their prevalence in craniosynostosis prior to craniofacial surgery. Methods: A systematic search was conducted on Medline OVID, Embase, Cochrane, Google Scholar, Web of Science Core Collection. Inclusion criteria were English papers, children aged <18 years with non-syndromic and syndromic craniosynostosis, case reports, case series, and case-control studies. A system of domains was established consisting of an anatomic and functional ophthalmic domain. A meta-analysis of single proportions was carried out using random effects model and pooled mean proportions with 95% confidence intervals (CI) were calculated. Results: Thirty-two papers analyzing 2027 patients were included. Strabismus was the most common anomaly in non-syndromic craniosynostosis: Horizontal strabismus was highest prevalent in unicoronal craniosynostosis (UCS) 19% (95% CI 9–32), followed by vertical strabismus 17% (95% CI 5–33). In syndromic craniosynostosis, horizontal strabismus was most prevalent in Crouzon syndrome 52% (95 CI 26–76), followed by Apert syndrome 50% (95% CI 42–58). Vertical strabismus was most prevalent in Saethre-Chotzen 60% followed by Muenke’s syndrome 36%. Furthermore, astigmatism was the second most reported outcome in non-syndromic craniosynostosis and highest prevalent in UCS 35% (95% CI 21–51). In syndromic craniosynostosis, astigmatism was most frequently seen in Crouzon syndrome 43% (95% CI 22–65), followed by Apert syndrome 34% (95% CI 14–58). Moreover, in syndromic craniosynostosis, 5–40% had a decrease in visual acuity (VA) ≤ 0.3 LogMAR in the better eye and 11–65% had a VA ≤ 0.3 LogMAR in at least one eye. Discussion: This review demonstrates the high prevalence of ocular anomalies in non-syndromic and syndromic craniosynostosis. A multidisciplinary and systematic approach is needed for the screening and optimal treatment of these conditions in a timely manner.

A Technique for Minimizing the Need for Hemotransfusion in Non-Syndromic Craniosynostosis Surgery

ABSTRACT

Surgery for craniosynostosis is associated with excessive blood loss, as well as morbidity and mortality risks. This study investigated the effectiveness of a surgical technique for nonsyndromic craniosynostosis intervention in controlling bleeding, assessed based on the volume of blood transfused. The cohort included 73 children who underwent nonsyndromic craniosynostosis surgery during a 3-year period. Retrospective evaluation of patient parameters included sex, weight, and age at the time of surgery; type of craniosynostosis; duration of surgery; hemoglobin concentration before and after surgery; rate of transfusion; and volume of transfused blood (mL/kg). The surgical technique involved skin incision and subgaleal dissection using electrocautery with a Colorado needle tip. The pericranium was not removed but instead kept in situ, and orbiectomy was performed using piezosurgery. Of the 73 children in the cohort, 75.3% underwent fronto-orbital advancement and were included in the analysis. The average age was 10.9 months (range: 4-96 months), with 68.5% boys and 31.5% girls (P < 0.001). The most common type of craniosynostosis was trigonocephaly (57.5%), followed by scaphocephaly (19.2%). The mean duration of the surgery was 2 hours and 55 minutes. Blood transfusion was needed in 56.2% of patients, with a mean volume of 8.7 mL/kg body weight transfused intraoperatively. No complications or fatalities were observed. These results suggested that meticulous, continuous control of homeostasis is paramount in minimizing blood loss during surgical repair of nonsyndromic craniosynostosis.

Impact of Obstructive Sleep Apnea on Optic Nerve Function in Patients With Craniosynostosis and Recurrent Intracranial Hypertension

PURPOSE

Assessment of combined impact of intracranial hypertension (ICH) and obstructive sleep apnea (OSA) on optic nerve function in children with craniosynostosis (CS).

DESIGN

Retrospective cross-sectional study.

METHODS

Patients treated at Boston Children's Hospital for CS who had an ophthalmic examination that included pattern reversal (pr)VEP (2013-2014) and history of ICH based on direct measurement, papilledema, or classic features on neuroimaging and during cranial vault expansion were included. History of OSA was determined by polysomnography and associated conditions, including apnea and (adeno)tonsillectomy. Subjects were divided into 4 groups: group 1, resolved ICH absent history of OSA; group 2, resolved ICH with history of OSA; group 3, recurrent ICH absent history of OSA; and group 4, recurrent ICH with history of OSA. Predictor variables included latency of P100 component of pattern-reversal visual evoked potential, best-corrected visual acuity, optic nerve appearance, visual fields, and global retinal nerve fiber layer. Primary outcome was association of prolonged P100 latency with resolved vs recurrent ICH and OSA.

RESULTS

Twenty-eight children met inclusion criteria (mean age 11.6 ± 6.9 years): group 1 (n = 3), group 2 (n = 6), group 3 (n = 8), and group 4 (n = 11). P100 latencies were not prolonged in groups 1 and 2. Three of 8 in group 3 and 9 of 11 in group 4 had prolonged P100 latency. Group 4 was significantly worse than group 3 (P = .005).

CONCLUSIONS

History of OSA, in addition to recurrent ICH, is associated with greatest risk of optic neuropathy with CS. Ophthalmologists should encourage early management of OSA as well as ICH to optimize ophthalmic outcomes.

Serial, Visually-Evoked Potentials for the Assessment of Visual Function in Patients with Craniosynostosis

This study aimed to evaluate the effect of craniofacial surgical intervention on the visual pathway's function by comparing pre- to post-operative patterned, visually-evoked potentials (pVEP). A retrospective review was conducted on craniosynostosis patients who had pre- and post-craniofacial surgery pVEP testing. The pVEP measured grade in terms of amplitude latency and morphology of the waveforms. The pre- and post-operative results were compared. The study identified 63 patients (mean age at preoperative pVEP of 16.9 months). Preoperatively, 33 patients (52.4%) had abnormal pVEP. Nine patients had evidence of intracranial hypertension, and of those, eight (88.9%) had abnormal pVEP. Within 6 months postoperatively, 24 of 33 patients (72.7%) with abnormal preoperative pVEP developed normal postoperative pVEP, while all 30 patients with normal preoperative VEP maintained their normal results postoperatively. Significant improvements in pVEP latency in patients with broad or delayed latency waveforms was evident for subjects with preoperative grades 2-4 (grade 2, p = 0.015; grade 3, p = 0.029; grade 4; p = 0.007), while significant postoperative increase in amplitude was significant for patients with abnormally low amplitude grade 3 and 5 waveforms (grade 3, p = 0.011; grade 5, p = 0.029). Serial pVEP testing represents a useful tool for the early detection of visual pathway dysfunction and follow up visual pathway function in craniosynostosis. Surgical intervention for craniosynostosis can result in the reversal of preoperative pVEP abnormalities seen in these patients, resulting in the normalization of the pVEP waveform, amplitude and latency, depending on the preoperative pVEP abnormality.

Visuomotor Function in School-Age Children with Single-Suture Craniosynostosis

OBJECTIVE

Previous studies have shown that infants and young children with single-suture craniosynostosis (SSC) perform more poorly on tests of visuomotor function than children without SSC. However, previous studies are limited by small sample sizes and little is known about the persistence of visuomotor problems into the school-age years. The aim of this study was to compare visuomotor function in children with and without SSC at the beginning of elementary school.

METHODS

The study included 179 children with SSC (cases) and 183 children without SSC (controls). Visuomotor function was measured by the NEPSY-II Arrows, the Purdue Pegboard Test, and the Beery-Buktenica Developmental Test of visual-motor integration. Case-control differences were estimated using linear regression, adjusted for age, sex, socioeconomic status, and maternal IQ.

RESULTS

Cases scored more poorly on all measures of visuomotor function, although the magnitude of case-control differences varied across measures. The greatest differences were observed for the Purdue Pegboard Test, with an average adjusted difference of -0.2 to -0.4 SD points (p-values ranged from .008 to .05). Case-control differences were small in magnitude for other measures of visuomotor function, ranging from -0.01 to -0.1 SD points (p-values ranged from .22 to .88).

CONCLUSION

Children with SSC experienced deficits in manual dexterity into the school-age years but were similar to children without SSC on measures of visual processing. These findings advocate for the assessment of fine-motor function as part of school readiness evaluations in children with SSC.

Intraoperative pre- and post-craniofacial reconstruction intracranial pressure (ICP) monitoring in children with craniosynostosis

INTRODUCTION

One of the goals of cranial vault expansion performed in patients with craniosynostosis (CS) is to reduce the harmful effects associated with elevated intracranial pressure (ICP). Until now, clear guidelines on when cranial vault expansion should take place have not been established except in unacceptable cosmetic deformities.

MATERIALS AND METHODS

This paper illustrates the potential benefit of ICP monitoring in determining the time of surgery. The ICP of six patients (ranging from 7 months to 8 years) was measured before and after surgery. For the first time, we regulated end-tidal carbon dioxide, the position and movements, the level of sedation and the monitoring site of our patients under anesthesia to report accurate ICP readings.

RESULTS

The mean pre- and postoperative ICPs were 14.7 and 4.2 mmHg, respectively. Pressure sensor was placed through a burr hole under general anesthesia and remained through all stages of recording. Though ICP monitoring has been reported before, the physiological fluctuations of ICP and patient's condition affected results. Under our ICP monitoring protocol, the six-patient study represents a suggestion to standardize ICP measurements under certain conditions in order to improve the reproducibility of ICP monitoring and therefore establish the need for optimal timing of cranial vault expansion in pediatrics.

CONCLUSION

Although we cannot clearly define the indications and establish normal pediatric ICP values from the result of this study because of the small number of cases and some other limitations, this is a new approach to define ICP increase as a potential indication for surgery in CS.

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.

Craniosynostosis-associated Fgfr2(C342Y) mutant bone marrow stromal cells exhibit cell autonomous abnormalities in osteoblast differentiation and bone formation

We recently reported that cranial bones of Fgfr2^C342Y/+ craniosynostotic mice are diminished in density when compared to those of wild type mice, and that cranial bone cells isolated from the mutant mice exhibit inhibited late stage osteoblast differentiation. To provide further support for the idea that craniosynostosis-associated Fgfr mutations lead to cell autonomous defects in osteoblast differentiation and mineralized tissue formation, here we tested bone marrow stromal cells isolated from Fgfr2^C342Y/+ mice for their ability to differentiate into osteoblasts. Additionally, to determine if the low bone mass phenotype of Crouzon syndrome includes the appendicular skeleton, long bones were assessed by micro CT. Fgfr2^C342Y/+ cells showed increased osteoblastic gene expression during early osteoblastic differentiation but decreased expression of alkaline phosphatase mRNA and enzyme activity, and decreased mineralization during later stages of differentiation, when cultured under 2D in vitro conditions. Cells isolated from Fgfr2^C342Y/+ mice also formed less bone when allowed to differentiate in a 3D matrix in vivo. Cortical bone parameters were diminished in long bones of Fgfr2^C342Y/+ mice. These results demonstrate that marrow stromal cells of Fgfr2^C342Y/+ mice have an autonomous defect in osteoblast differentiation and bone mineralization, and that the Fgfr2^C342Y mutation influences both the axial and appendicular skeletons.

Further analysis of the Crouzon mouse: effects of the FGFR2(C342Y) mutation are cranial bone-dependent

Crouzon syndrome is a debilitating congenital disorder involving abnormal craniofacial skeletal development caused by mutations in fibroblast growth factor receptor-2 (FGFR2). Phenotypic expression in humans exhibits an autosomal dominant pattern that commonly involves premature fusion of the coronal suture (craniosynostosis) and severe midface hypoplasia. To further investigate the biologic mechanisms by which the Crouzon syndrome-associated FGFR2(C342Y) mutation leads to abnormal craniofacial skeletal development, we created congenic BALB/c FGFR2(C342Y/+) mice. Here, we show that BALB/c FGFR2(C342Y/+) mice have a consistent craniofacial phenotype including partial fusion of the coronal and lambdoid sutures, intersphenoidal synchondrosis, and multiple facial bones, with minimal fusion of other craniofacial sutures. This phenotype is similar to the classic and less severe form of Crouzon syndrome that involves significant midface hypoplasia with limited craniosynostosis. Linear and morphometric analyses demonstrate that FGFR2(C342Y/+) mice on the BALB/c genetic background differ significantly in form and shape from their wild-type littermates and that in this genetic background the FGFR2(C342Y) mutation preferentially affects some craniofacial bones and sutures over others. Analysis of cranial bone cells indicates that the FGFR2(C342Y) mutation promotes aberrant osteoblast differentiation and increased apoptosis that is more severe in frontal than parietal bone cells. Additionally, FGFR2(C342Y/+) frontal, but not parietal, bones exhibit significantly diminished bone volume and density compared to wild-type mice. These results confirm that FGFR2-associated craniosynostosis occurs in association with diminished cranial bone tissue and may provide a potential biologic explanation for the clinical finding of phenotype consistency that exists between many Crouzon syndrome patients.

Effects of different surgical techniques on cephalic index and intracranial volume in isolated bilateral coronal synostosis model

BACKGROUND

Bilateral coronal synostosis (brachycephaly) is the most common single-suture synostosis that may lead to functional deficits such as mental retardation. This increases the importance of volume gain during surgery. This study was designed to understand the differences in volume gain, cranial index (CI), and aesthetic outcomes when additional osteotomies or rotations are applied on the frontoparietal segment.

METHODS

Acrylic brachycephaly models were prepared. Frontoparietal osteotomy was standard in all models. Frontoparietal segment was fixed: to the same position in surgical control model, after 1.2-cm advancement in advancement model, after 180-degree rotation without advancement in rotation model, after 180-degree rotation plus a horizontal osteotomy and 1.2-cm advancement in rotation plus angled advancement model, and after a horizontal osteotomy without rotation and 1.2-cm advancement and in angled advancement model.

RESULTS

Intracranial volume changes (in milliliters) and CIs were as follows between groups: control group, 828/94.1; surgical control group, 830/93.8; advancement model, 900/84.5; rotation model, 834/89.1; rotation plus angled advancement model, 897/82.7; angled advancement model, 902/81.8.

CONCLUSIONS

Advancement of the frontoparietal segment is the keystone of surgery in brachycephaly treatment. Making an additional horizontal osteotomy can angle this segment and may supply additional volume gain. Rotation of the frontoparietal segment does not provide additional volume or CI gain but increase better aesthetic outcomes.

Craniofacial reconstruction as a treatment for elevated intracranial pressure

INTRODUCTION

Craniofacial procedures may be needed to address symptomatic intracranial hypertension. The authors review their institutional experience in the treatment of children with symptomatic increased intracranial pressure (ICP) utilizing craniofacial reconstructive procedures.

METHODS

The senior authors' (HSM, SRC) craniofacial experience of 222 patients over a 7-year period from 2000 to 2007 at a single institution (Rady Children's Hospital, San Diego) is reviewed. Seventeen patients were identified who were felt to be candidates for craniofacial surgery with symptomatic increased ICP.

RESULTS

Patient diagnoses included single-suture craniosynostosis, craniofacial dysostoses, shunt-induced craniostenosis, and shunt-associated intracranial hypertension (slit-ventricle syndrome). Seventeen patients underwent 21 craniofacial procedures. Age at surgery ranged from 3 months to 13 years with a mean of 5 years. Preoperative symptoms and signs included headaches, unexplained irritability, seizures, papilledema, and visual loss. All patients had diagnostic neuroimaging. Seven patients had preoperative invasive ICP measurements. Surgery was deferred on three of these patients based on these measurements. The mean total operative (including anesthetic preparation) and surgical times were 3 h 12 min and 2 h 20 min, respectively. Percentage operative blood loss averaged 11.3%. In six procedures, no transfusions were required. Average hospital stay was 4 days. There was no perioperative mortality or significant surgery associated morbidity. All patients have had postoperative clinical improvement in signs and symptoms of increased ICP.

CONCLUSIONS

Using modern diagnostic and surgical techniques, including invasive ICP monitoring, increased intracranial pressure can be successfully managed by an experienced, multidisciplinary, craniofacial team. Our treatment paradigm and operative management scheme is discussed.

Difficulties of delayed treatment of craniosynostosis in a patient with Crouzon, increased intracranial pressure, and papilledema

Crouzon syndrome is an autosomal dominant disorder characterized by cranial synostosis, hypertelorism, orbital proptosis, parrot-beaked nose, short upper lip, hypoplastic maxilla, and a relative mandibular prognathism, without extremity involvement. Surgical intervention should occur at the onset of progressive craniosynostosis to treat or to prevent intracranial hypertension and visual impairment. Throughout developing countries, early treatment is often not a viable option. Often, the only option for treatment is through humanitarian missions. Appropriate preselection of surgical patients is essential, as is having a multidisciplinary team and a well-equipped hospital and staff to perform the operations and to care for the postsurgical patient. This type of humanitarian care benefits the patient selected to receive the intense logistical and financial effort when there is no possibility of timely care in their own countries. This clinical report describes a patient with Crouzon syndrome brought to the United States from a developing country through humanitarian efforts. She presented at 19 months of age with bicoronal and sagittal synostosis and advanced visual impairment and papilledema. Surgical intervention included cranial expansion and reconstruction with a multidisciplinary team. This case illustrates not only the difficulty of delayed treatment but also some of the issues arising from this type of humanitarian medical care.

Why do we behave as we do?

It is important for surgeons to have insight into themselves, their life stories, and the rationales they use to convince themselves that their actions are unselfish and well motivated. The battle between Philanthropia and Philotechnica was recognized by Hippocrates and is still a source of internal strife for many surgeons: the need to perform an operation that they are poorly equipped to do offset against the knowledge that it could be better done by someone else. In the treatment or referral for treatment of children with craniosynostosis and craniofacial syndromes, appropriate referrals are often not made or are made only after some problem has occurred as a result of surgical intervention. Several instances of children receiving extensive surgery for wrongly diagnosed craniosynostosis are explored. The thesis is that only by knowing our own internal motivations can we avoid falling into a posture that is good for our own egos and pocketbooks but bad for our patients.

Age-related peridural hyperemia in craniosynostotic rabbits

OBJECTIVE

Craniosynostosis is the premature fusion of the calvarial sutures and is associated with aesthetic impairment and secondary damage to brain growth. Associated neurological injuries can result from increased intracranial pressure (ICP) and abnormal cerebral blood flow (CBF). Arterial spin-labeling (ASL) MRI was used to assess regional CBF in developing rabbits with early-onset coronal suture synostosis (EOCS) and age-matched wild-type controls (WT).

METHODS

Rabbits were subjected to ASL MRI at or near 10, 25, or 42 days of age. Differences in regional CBF were assessed using one-way ANOVA.

CONCLUSION

CBF was similar in WT and EOCS rabbits with the exception of the peridural surfaces in EOCS rabbits at 25 days of age. A twofold increase in peridural CBF at 25 days of age coincides with a transient increase in ICP. By 42 days of age, CBF in peridural surfaces had decreased.

Pansynostosis: a review

INTRODUCTION

Although rare, pansynostoses are seen and treated by the craniofacial surgeon. To date, a single source that reviews these more severe forms of craniosynostosis is lacking in the literature.

MATERIALS AND METHODS

The present paper outlines and reviews the associations of both syndromic and nonsyndromic cases, potential mechanisms, and the anatomy involved with such forms of premature fusion of the cranial sutures.

RESULTS

Pansynostosis is seen in a myriad of syndromes but can also be identified in nonsyndromic cases. Raised intracranial pressure is a concern in these patients.

CONCLUSIONS

Early recognition and treatment of patients with pansynostosis of the cranial sutures is important.

Correction of sagittal craniosynostosis using a novel parietal bone fixation technique: results over a 10-year period

Isolated sagittal synostosis is a common form of craniosynostosis affecting roughly 1 in 5,000 children at birth. This results in a scaphocephalic head shape with a characteristically elongated anterior-posterior dimension and narrowed biparietal diameter. We present our experience with the correction of scaphocephaly due to sagittal synostosis using cranial vault reconstruction with a novel form of parietal bone fixation in 21 patients over 10 years. The medial fixation results in a hinging effect whereby transverse brain growth at the squamoid suture is enhanced. This results in excellent cosmetic results that are immediate and durable without the need for postoperative molding helmets. Furthermore, the complications associated with this procedure are limited.

Testing causal mechanisms of nonsyndromic craniosynostosis using path analysis of cranial contents in rabbits with uncorrected craniosynostosis

OBJECTIVE

Various causal mechanisms of familial nonsyndromic craniosynostosis have been presented. One hypothesis suggests that overproduction of bone at the suture is the primary origin of craniosynostosis, which affects brain and cranial growth secondarily through altered intracranial pressure (Primary Suture Fusion Model). Other hypotheses suggest that decreased cranial base growth or abnormal brain growth are the primary cause of craniosynostosis (Cranial Base, Brain Parenchyma Models, respectively). This study was designed to investigate which model best describes neurocranial changes associated with craniosynostosis in a rabbit model through multivariate path analysis.

DESIGN

Serial magnetic resonance imaging scans and intracranial pressure measurements were obtained at 10, 25, and 42 days of age from 18 rabbits: six controls, six with delayed-onset synostosis, and six with early-onset synostosis. Five variables were collected from each rabbit: calvarial thickness at the affected suture, cranial base length, brain volume, cerebrospinal fluid volume, and intracranial pressure. This data set was used to test causal pathway relationships generated by the proposed models. Goodness of fit was measured by experimental group for each model.

RESULTS

Primary Suture Fusion Model best explained the variables in both delayed-onset and early-onset synostotic rabbits (Goodness of fit = 93%, 97%, respectively). Cranial Base Model (Goodness of fit = 94%) best explained the data in control rabbits.

CONCLUSION

Results suggest that the primary site of craniosynostosis in craniosynostotic rabbits is most likely the synostosed suture. Other cranial vault anomalies are most likely secondary compensatory changes. Results of the present study may provide insight regarding the causal pathway of craniosynostosis.

Prevalence of Abnormal Pattern Reversal Visual Evoked Potentials in Craniosynostosis

BACKGROUND

The purpose of this study was to examine the prevalence and type of changes observed in the pattern reversal visual evoked potentials recorded at the first assessment of children with craniosynostosis.

METHODS

Visual evoked potentials were recorded from 114 patients with craniosynostosis. Eighty-one patients were syndromic and 33 were nonsyndromic. No patient had received any craniofacial surgical intervention. At the time of the test, 22 of 40 patients were aged 6 months and younger, and 18 patients were between 6 months and 1 year of age. Pattern reversal visual evoked potentials were recorded from a midoccipital electrode positioned 3 cm above the inion. The pattern reversal visual evoked potentials elicited to 50' checks with three reversals per second viewed with both eyes were analyzed for n80-p100 amplitude, p100 latency, and breadth of waveform.

RESULTS

Sixty percent of patients had abnormal pattern reversal visual evoked potentials to 50' checks. This did not show a significant association with age, or classification of craniosynostosis.

CONCLUSIONS

The high prevalence of abnormal pattern reversal visual evoked potentials to a robust stimulus suggests that visual pathway dysfunction, as measured electrophysiologically, can affect a majority of patients with craniosynostosis. This study indicates that a baseline evaluation of all children with craniosynostosis at their first presentation is essential if subsequent electrophysiologic visual pathway monitoring is to take place.

Case report of optic atrophy in pansynostosis: an unusual presentation of scalp edema from hair braiding

Pansynostosis (fusion of all cranial sutures) and optic atrophy were found as incidental CT scan and ophthalmological findings in an 8-year-old who presented to the emergency room with scalp edema from tight 'cornrow' hair braiding. Cranial vault expansion was successfully performed. Ophthalmological problems have stabilized but have not reversed. Late presentation of craniosynostosis and the pathophysiology of secondary optic atrophy are discussed.

Skull vault growth in craniosynostosis

BACKGROUND

Since its first description by Virchow, the principle of abnormal skull growth due to restriction of skull growth at the fused sutures, and the realisation by Moss that the sutures at the skull base are equally affected, have been the main intellectual driving forces behind the majority of cranial expansion procedures performed currently in children with craniosynostosis.

CURRENT OBSERVATIONS

Despite original impressions that craniosynostosis leads to craniostenosis, many studies have demonstrated that in the majority of patients with craniosynostosis there is normal skull volume in those over the age of 6 months. In Apert syndrome, skull volume is invariably larger than normal. Some studies have shown that intracranial pressure is independent of intracranial volume, and can exist in the presence of normal volume, or indeed after cranial expansion. These observations imply that cranial expansion procedures create a state of artificially increased skull volume, in the quest to improve appearance and function.

FUTURE ADVANCES

This creates a new angle of view through which skull growth abnormalities are seen. It is becoming clearer that in most patients with craniosynostosis, there is regional imbalance of skull growth, which co-exists with a variety of other equally important factors, such as genetic defects, raised intracranial pressure, venous hypertension, and other brain parenchymal anomalies such as hindbrain hernia or hydrocephalus. It is becoming increasingly obvious that the type of surgical treatment currently practised in most cases is conceptually incorrect. Recent modifications such as the use of springs or distraction do not escape from the underlying philosophy of cranial expansion. With that in mind, it is hoped that advances in the fields of genetics and molecular biology will provide treatments for the cause of craniosynostosis rather than the symptomatic relief that surgery offers currently.

CONCLUSION

Until then, there is a need to develop better ways of quantifying regional abnormalities of skull growth.

FGFR3 P250R mutation increases the risk of reoperation in apparent 'nonsyndromic' coronal craniosynostosis

Many patients with a clinical diagnosis of "nonsyndromic" coronal craniosynostosis have been found to be heterozygous for the fibroblast growth factor receptor 3 (FGFR3) mutation Pro250Arg. The phenotype associated with this mutation is variable and lacks highly distinctive features, so it is difficult to diagnose on clinical examination alone. The authors present a retrospective study of 76 patients with isolated coronal synostosis who were operated on in a single dedicated craniofacial unit over 25 years. The authors investigated whether any single factor, including the presence of a FGFR3 Pro250Arg mutation, predisposed to an increased transcranial reoperation rate. Eight patients had repeat transcranial surgery for a functional indication. Heterozygosity for the FGFR3 Pro250Arg mutation, present in 29 patients in the cohort, was the only factor found to have a significant association (P=0.048) with the transcranial reoperation rate. Six patients (20.7%) with the mutation underwent reoperation on the basis of raised intracranial pressure, as compared with two patients (4.3%) without the mutation. This highlights the need for genetic analysis and long-term clinical follow-up in apparently "isolated" coronal synostosis.

Adenoid-tonsillectomy to treat visual dysfunction in a child with craniosynostosis

We report a child with isolated saggital synostosis where a gradual deterioration of the P100 component of the pattern reversal visual evoked potential recorded during the day was associated with episodes of upper airway obstruction during sleep that correlated with periods of ICP spiking. Adenoid-tonsillectomy reversed this deterioration with coincident increase in SaO2 and decreased sleep apnoea.

Age-related changes in lateral ventricle morphology in craniosynostotic rabbits using magnetic resonance imaging

BACKGROUND AND AIMS

Craniosynostosis occurs in 300-500 per 1,000,000 live births and results in secondary craniofacial, ocular, and intracranial anomalies. Neurologic problems associated with craniosynostosis include changes in intracranial morphology such as dilation of the cerebral ventricles, however, clinical studies are confounded by small sample sizes, heterogenous samples, and lack of age-matched controls. The present study was designed to assess age-related changes in the lateral ventricle volume of the brain in normal rabbits and rabbits with naturally-occurring coronal suture synostosis using serial magnetic resonance imaging.

METHODS

Eighteen rabbits (6 wild-type controls, 6 with early-onset [ approximately 21 days gestation], and 6 with delayed-onset [approximately 25 days post-gestation] coronal suture synostosis) had magnetic resonance imaging (MRI) at 10, 25, and 42 days of age.

RESULTS

The results demonstrate that rabbits with early-onset synostosis had significantly (p<0.001) dilated and larger lateral ventricles (by 77% at 10 days of age) than wild-type and delayed-onset synostosis rabbits, which progressively worsened by day 42.

CONCLUSION

This finding suggests that uncorrected coronal suture synostosis may have early effects on lateral ventricle volume hypertrophy, possibly through obstructed cerebrospinal fluid and/or venous drainage and circulation.

Visual Loss in Syndromic Craniosynostosis With Papilledema But Without Other Symptoms of Intracranial Hypertension

Four children with syndromic craniosynostosis (Crouzon's syndrome and Apert syndrome) developed irreversible visual loss. Apart from papilledema, there were no other clinical symptoms of intracranial hypertension. Ventriculomegaly or hydrocephalus was present in all cases. Two children were known to have obstructive sleep apnea syndrome. These cases are reported to inform specialists involved in follow-up of children with syndromic craniosynostosis that visual loss can develop suddenly without other symptoms of intracranial hypertension. To prevent visual loss, papilledema should be detected at an early stage and intervention should be instituted promptly. Therefore, periodic funduscopy should be performed in children at risk, such as children with syndromic craniosynostosis and additional hydrocephalus or obstructive sleep apnea syndrome.

Mild trigonocephaly and intracranial pressure: report of 56 patients

INTRODUCTION

We report the surgical results in patients with mild trigonocephaly and clinical symptoms. Since high intracranial pressure (ICP) was noted during surgery in our previous patient series, we began to record intraoperative ICP. The importance of treating mild trigonocephaly with clinical symptoms is stressed.

PATIENTS AND METHODS

Fifty-six children (44 boys, 12 girls) in whom ICP was measured were diagnosed with mild trigonocephaly (nonsyndromic type) with symptoms such as language delay, hyperactivity, autistic tendencies, self-mutilation, motor delay, etc. Their ages ranged from 2 to 8 (mean 5.1) years. ICP was measured after a burr hole was made under endotracheal general anesthesia and a sensor was inserted in the right frontal lobe epidurally immediately in front of the right coronal suture. The first recordings were made at around 30 mmHg of PCO(2) as for neuroanesthesia, and the second were at around 40 mmHg of PCO(2) as during natural breathing. We also investigated which factors accounted for the improvement of clinical symptoms.

RESULTS

The first ICP records at 29.1 mmHg of PCO(2) indicated a mean ICP of 13.3 mmHg. The second changed to a mean 38.2 mmHg of PCO(2) for an increased mean ICP of 19.8 mmHg. The pulse pressures were a mean 7.1 mmHg in the first recordings and 8.5 mmHg in the second. The mean ICP and pulse pressure were thus high in these children. Clinically, 30 out of 56 patients improved markedly and 22 improved slightly, while 4 did not exhibit any change. Factors contributing to improvement were younger age, relatively higher development quotient, marked digital impressions on skull X-rays, abnormal findings on SPECT, and moderate degree of trigonocephaly.

CONCLUSION

Although our patients had mild trigonocephaly, their ICP and pulse pressure were high. Decompressive cranioplasty in cases of mild trigonocephaly is feasible.

Intracranial Pressure Changes in Craniosynostotic Rabbits

Cranial vault and brain deformities in individuals with craniosynostosis are thought to result, in part, from changes in intracranial pressure, but clinical findings are still inconclusive. The present study describes intracranial pressure changes in a rabbit model with naturally occurring, uncorrected coronal suture synostosis. Longitudinal and cross-sectional intracranial pressure data were collected from 241 New Zealand White rabbits, divided into four groups: normal controls (n = 81); rabbits with delayed-onset coronal suture synostosis (n = 78); rabbits with early-onset unilateral coronal suture synostosis (n = 32); and rabbits with early-onset bilateral coronal suture synostosis (n = 50). Epidural intracranial pressure measurements were obtained at 10, 25, 42, and 84 days of age using a NeuroMonitor microsensor transducer. Normal rabbits and rabbits with delayed-onset coronal suture and early-onset unilateral coronal suture synostosis showed a similar oscillating pattern of age-related changes in normal and head-down intracranial pressure from 10 to 84 days of age. In contrast, rabbits with early-onset bilateral coronal suture synostosis showed markedly elevated normal and head-down intracranial pressure levels from 10 to 25 days and showed a different pattern through 84 days. Results from one-way analysis of variance revealed significant (p < 0.01) group differences only at 25 days of age. Rabbits with early-onset bilateral coronal suture synostosis had significantly (p < 0.05) greater normal and head-down intracranial pressure (by 42 percent) than the other three groups. These results showed differing intracranial pressure compensations in rabbits with uncorrected multiple-suture synostosis compared with normal rabbits or rabbits with uncorrected single-suture synostosis, possibly through progressive cerebral atrophy and decreased intracranial volume, abnormal intracranial vascular patterns and blood volume, and/or differing cranial vault compensatory changes.

Advances in Craniosynostosis Research and Management

The purpose of the present paper is to analyze the most recent advances in the field of craniosynostosis basic and clinical research and management, and to give an overview of the more frequently adopted surgical strategies. After reviewing some basic concepts regarding normal craniofacial embryology and growth, aetiopathogenesis of craniosynostosis and craniofacial dysostosis, classification and diagnosis and historical evolution of surgical treatment, the authors elaborate on a selection of topics that have modified our current understanding of and therapeutical approach to these disease processes. Areas covered include advances in molecular biology and genetics, imaging techniques and surgical planning, resorbable fixation technology, bone substitutes and tissue engineering, distraction osteogenesis and the spring-mediated cranioplasties, resorbable distractor devices, minimally invasive surgery and in utero surgery. A review of the main subtypes of craniosynostosis and craniofacial dysostosis is presented, including their specific clinical features and a commentary on the presently available surgical options.

Clinical findings precede objective diagnostic testing in the identification of increased ICP in syndromic craniosynostosis

Crouzon syndrome is an autosomal dominant disorder resulting in facial dysmorphism and craniosynostosis involving multiple cranial sutures. A common but often unrecognized early complication associated with craniosynostosis is a finding of increased intracranial pressure (ICP). This increase in ICP can lead to optic atrophy, neuronal damage, and mental deficits. The case of a 21-month-old girl with Crouzon syndrome is described. Although the child was clinically asymptomatic, a routine ophthalmic exam revealed papilledema and subsequently increased intracranial pressure and craniosynostosis were found. Cranial expansion and bicanthal advancement were performed to relieve the increased pressure. In cases such as these, long-term follow-up is essential because of the progressive nature of the disorder as well as the possibility of a recurrence of elevated intracranial pressure and a need for secondary decompressive surgery.

[Surgery for craniosynostosis: timing and technique]

Craniosynostoses are a group of diseases, the presentation of which differs markedly on account of the cranial suture involved. Their impact is cosmetic, cerebral, and ophthalmologic. Syndromic craniosynostoses associate a more or less pronounced faciostenosis, which requires surgical correction as well, because of cosmetic, ophthalmologic or airway problems. Surgical treatment depends on the type of the craniosynostosis and the patient's age; ideally, the child should be operated between 3 and 12 months. This surgery requires a perfect collaboration between neurosurgeon, plastic surgeon, and anaesthesiologist. Surgical correction allows in large measures the preservation of intellect, sight, and body image.

Enigma of raised intracranial pressure in patients with complex craniosynostosis: the role of abnormal intracranial venous drainage

OBJECT

In this study the authors investigated whether patterns of intracranial venous drainage in children with complex craniosynostosis associated with raised intracranial pressure (ICP) were abnormal and, thus, could support the theory that venous hypertension is a major contributor to raised ICP that can lead to impaired visual function or even blindness in these patients.

METHODS

The authors analyzed the anatomy of intracranial venous drainage as demonstrated in the results of 24 angiography studies obtained in 23 patients, all of whom had either a craniosynostosis-related syndrome (18 patients) or a nonsyndromic multisutural synostosis (five patients). Twenty-one patients had experienced raised ICP (in 19 patients diagnosis was based on invasive ICP monitoring and in two patients on clinical grounds alone) 1 to 6 weeks before undergoing angiography. Of the two remaining patients (both with Apert syndrome) whose ICP monitoring was normal immediately before angiography, each had undergone two previous cranial vault expansion procedures. On results of 18 angiography studies a 51 to 99% stenosis or no flow at all could be observed in the sigmoid-jugular sinus complex either bilaterally (11 patients) or unilaterally (seven patients). In 11 of these patients a florid collateral circulation through the stylomastoid emissary venous plexus was also seen. Two angiography studies were performed in one patient with Crouzon syndrome. A comparison of the two studies demonstrated a progression of the abnormal venous anatomy in that case. The authors found no obvious correlation between each patient's baseline ICP and the degree of abnormality of their venous anatomy, as judged on the basis of a venous-phase angiography severity score.

CONCLUSIONS

Based on their findings, the authors assert that in children with complex forms of craniosynostosis in whom other factors, such as hydrocephalus, are absent, abnormalities of venous drainage that particularly affect the sigmoid-jugular sinus complex produce a state of venous hypertension that, in turn, is responsible for the majority of cases of raised ICP. The incidence of these changes is unknown, but an analysis of the ages of the children in this study indicated that the period of particular vulnerability to the effects of venous hypertension lasts until the affected child is approximately 6 years old. After that age the collateral venous drainage through the stylomastoid plexus will likely become sufficient to allow ICP to normalize.

Age-related changes in intracranial pressure in rabbits with uncorrected familial coronal suture synostosis

OBJECTIVE

Chronic, elevated intracranial pressure (ICP) in craniosynostotic infants may result in ocular and neurocapsular problems; however, not all infants exhibit elevated ICP. Clinical ICP studies are further confounded by small and heterogeneic samples, multiple-suture involvement, and varying surgical management protocols. The present study was designed to describe longitudinal changes in ICP in a large, homogenous sample of rabbits with uncorrected familial, nonsyndromic coronal suture synostosis.

METHODS

Ninety-one rabbits were divided into four groups: (1) normal rabbits (n = 28), (2) rabbits with delayed-onset coronal suture synostosis (DOCS; n = 25), (3) rabbits with unilateral coronal suture synostosis (UCS; n = 12), and (4) rabbits with bilateral coronal suture synostosis (BCS; n = 26). ICP was measured at 24 and 42 days of age using a Codman epidural microtransducer.

RESULTS

Rabbits with BCS had a significantly (p < .05) higher mean ICP at 25 days of age than rabbits in the other three groups by approximately 146%. However, by 42 days of age, mean ICP in normal control rabbits and rabbits with DOCS was significantly (p < .01) increased compared with their mean ICP values seen at 25 days of age, while mean ICP in BCS rabbits significantly (p < .01) decreased (by 32%) over the same time period. ICP in rabbits with UCS was between that seen in normal control rabbits and rabbits with BCS and did not significantly (p > .05) change over time.

CONCLUSIONS

These findings suggest that the degree of suture involvement may be related to early increases in ICP. Possible multifactorial explanations for intracranial decompression and compensation in the craniosynostotic rabbit model are discussed.