Visual outcomes and amblyogenic risk factors in craniosynostotic syndromes: a review of 141 cases.

AIMS: To determine the visual outcome and prevalence of amblyogenic risk factors in children with craniosynostotic syndromes. METHODS: The case notes of 141 children seen within the craniofacial unit were reviewed and information retrieved on date of birth, age at first and last examination, cycloplegic refraction at last visit, best corrected visual acuity at last visit, horizontal ocular deviation in primary position at first visit, and alphabet pattern if any. The presence of astigmatism, its magnitude, and orientation of axis were determined. RESULTS: 40.3% of patients had 1 dioptre (D) of astigmatism or greater and, of these, 64% had oblique astigmatism in at least one eye. Anisometropia of 1D or more was found in 18% of patients (age matched normals 3.5%). Horizontal strabismus was found in 70% (38% exotropia, 32% esotropia). Visual outcome results showed 39.8% of patients (45 of 113) had visual acuity of 6/12 or worse in their better eye. CONCLUSION: In the largest study to date a poor visual outcome was shown in children with Crouzon's, Pfeiffer's, Apert's, and Saethre-Chotzen syndromes (39.8% with 6/12 or worse in the better eye) together with significant prevalence of amblyogenic risk factors.

Are routine preoperative CT scans necessary in the management of single suture craniosynostosis?

CT scanning is accepted as a regular component of the investigation of patients with simple craniosynostosis. In a series of 109 cases with simple craniosynostoses treated at Great Ormond Street Hospital for Children, a correct diagnosis on the basis of clinical findings was made in 100% of cases by an experienced clinician. CT scans with 3D reconstructions provided diagnostic confirmation in 100% of the patients when performed, but 91% of patients had already had sufficient confirmation of diagnosis by radiography. The clinical use of the scans for purposes other than diagnosis was examined. CT scanning in simple craniosynostosis in this series did not provide any additional clinical benefit as a screening method for the detection of intracranial abnormalities or for surgical planning. We propose that it may be appropriate to limit CT scanning, both axial images and three dimensional reconstructions, to selected cases where diagnostic uncertainty exists or where, it is used in surgical planning.

Ventriculoperitoneal shunt block: what are the best predictive clinical indicators?

AIMS: To evaluate the predictive value of symptoms, signs, and radiographic findings accompanying presumed ventriculoperitoneal (VP) shunt malfunction, by comparing presentation with operative findings and subsequent clinical course. METHODS: Prospective study of all 53 patient referrals to a paediatric neurosurgical centre between April and November 1999 with a diagnosis of presumed shunt malfunction. Referral pattern, presenting symptoms and signs, results of computed tomography (CT) scanning, operative findings, and clinical outcome were recorded. Two patient groups were defined, one with proven shunt block, the other with presumed normal shunt function. Symptomatology, CT scan findings, and the subsequent clinical course for each group were then compared. RESULTS: Common presenting features were headache, drowsiness, and vomiting. CT scans were performed in all patients. Thirty seven had operatively proven shunt malfunction, of whom 34 had shunt block and three shunt infection; 84% with shunt block had increased ventricle size when compared with previous imaging. For the two patient groups (with and without shunt block), odds ratios with 95% confidence intervals on their presenting symptoms were headache 1.5 (0.27 to 10.9), vomiting 0.9 (0.25 to 3.65), drowsiness 10 (0.69 to 10.7), and fever 0.19 (0.03 to 6.95). Every patient with ventricular enlargement greater than their known baseline had a proven blocked shunt. CONCLUSIONS: Drowsiness is by far the best clinical predictor of VP shunt block. Headache and vomiting were less predictive of acute shunt block in this study. Wherever possible CT scan findings should be interpreted in the context of previous imaging. We would caution that not all cases of proven shunt blockage present with an increase in ventricle size.

From genotype to phenotype: the differential expression of FGF, FGFR, and TGFbeta genes characterizes human cranioskeletal development and reflects clinical presentation in FGFR syndromes.

Mutations in the fibroblast growth factor receptor (FGFR) genes 1, 2, and 3 are causal in a number of craniofacial dysostosis syndromes featuring craniosynostosis with basicranial and midfacial deformity. Great clinical variability is displayed in the pathologic phenotypes encountered. To investigate the influence of developmental genetics on clinical diversity in these syndromes, the expression of several genes implicated in their pathology was studied at sequential stages of normal human embryo-fetal cranial base and facial ossification (n = 6). At 8 weeks of gestation, FGFR1, FGFR2, and FGFR3 are equally expressed throughout the predifferentiated mesenchyme of the cranium, the endochondral skull base, and midfacial mesenchyme. Both clinically significant isoforms of FGFR2, IgIIIa/c and IgIIIa/b, are coexpressed in maxillary and basicranial ossification. By 10 to 13 weeks, FGFR1 and FGFR2 are broadly expressed in epithelia, osteogenic, and chondrogenic cell lineages. FGFR3, however, is maximally expressed in dental epithelia and proliferating chondrocytes of the skull base, but poorly expressed in the osteogenic tissues of the midface. FGF2 and FGF4, but not FGF7, and TGFbeta1 and TGFbeta3 are expressed throughout both osteogenic and chondrogenic tissues in early human craniofacial skeletogenesis. Maximal FGFR expression in the skull base proposes a pivotal role for syndromic growth dysplasia at this site. Paucity of FGFR3 expression in human midfacial development correlates with the relatively benign human mutant FGFR3 midfacial phenotypes. The regulation of FGFR expression in human craniofacial skeletogenesis against background excess ligand and selected cofactors may therefore play a profound role in the pathologic craniofacial development of children bearing FGFR mutations.

Adverse operative events in neurosurgical training: incidence, trends and proposals for prevention.

We prospectively studied the adverse operative events encountered during the first 4.5 years of a single neurosurgeon's career (JP). We investigated the incidence of these events and their distribution over time, and recorded risk factors in causation. Twenty-three adverse events were identified in 728 cases studied. These all occurred in one of four categories of operation: craniotomy, shunt placement, spinal surgery and stereotactic biopsy. The incidence of adverse operative events varied between 5.8% for spinal operations to 9.5% for stereotactic biopsy. There was evidence of a reducing incidence of adverse operative events over time in some operative groups. The two categories with the highest incidence of adverse operative events were the same two categories with the lowest number of assisted cases per 100 operations performed.

Negative autoregulation of fibroblast growth factor receptor 2 expression characterizing cranial development in cases of Apert (P253R mutation) and Pfeiffer (C278F mutation) syndromes and suggesting a basis for differences in their cranial phenotypes.

OBJECT: Heterogeneous mutations in the fibroblast growth factor receptor 2 gene (FGFR2) cause a range of craniosynostosis syndromes. The specificity of the Apert syndrome-affected cranial phenotype reflects its narrow mutational range: 98% of cases of Apert syndrome result from an Ser252Trp or Pro253Arg mutation in the immunoglobulin-like (Ig)IIIa extracellular subdomain of FGFR2. In contrast, a broad range of mutations throughout the extracellular domain of FGFR2 causes the overlapping cranial phenotypes of Pfeiffer and Crouzon syndromes and related craniofacial dysostoses. METHODS: In this paper the expression of FGFR1, the IgIIIa/c and IgIIIa/b isoforms of FGFR2, and FGFR3 is investigated in Apert syndrome (P253R mutation)- and Pfeiffer syndrome (C278F mutation)-affected fetal cranial tissue and is contrasted with healthy human control tissues. Both FGFR1 and FGFR3 are normally expressed in the differentiated osteoblasts of the periosteum and osteoid, in domains overlapped by that of FGFR2, which widely include preosseous cranial mesenchyme. Expression of FGFR2, however, is restricted to domains of advanced osseous differentiation in both Apert syndrome- and Pfeiffer syndrome-affected cranial skeletogenesis in the presence of fibroblast growth factor (FGF)2, but not in the presence of FGF4 or FGF7. Whereas expression of the FGFR2-IgIIIa/b (KGFR) isoform is restricted in normal human cranial osteogenesis, there is preliminary evidence that KGFR is ectopically expressed in Pfeiffer syndrome-affected cranial osteogenesis. CONCLUSIONS: Contraction of the FGFR2-IgIIIa/c (BEK) expression domain in cases of Apert syndrome- and Pfeiffer syndrome-affected fetal cranial ossification suggests that the mutant activation of this receptor, by ligand-dependent or ligand-independent means, results in negative autoregulation. This phenomenon, resulting from different mechanisms in the two syndromes, offers a model by which to explain differences in their cranial phenotypes.

Tumescent steroid infiltration to reduce postoperative swelling after craniofacial surgery.

Steroids are often administered to paediatric craniomaxillofacial patients perioperatively to reduce postoperative facial swelling, although there is little evidence of their efficacy. Preoperative tumescent infiltration using 7 ml x kg(-1) of a solution consisting of 0.1 mg x ml(-1) triamcinolone acetate, 0.0125% bupivacaine, 0.025% lignocaine, 3 units x ml(-1) hyaluronidase and 1:1000000 adrenaline in Hartmann's solution was evaluated from a retrospective case controlled study of patients undergoing standard fronto-orbital remodelling for simple craniosynostosis (n = 20). Eye closure (i.e. inability to open the eyes) was used as a marker for severe facial swelling. Patients receiving the tumescent infiltration demonstrated significantly less eye closure (P < 0.005), implying that the tumescent infiltration had a significant effect on facial swelling. The avoidance of eye closure allowed more effective monitoring for neurological and ophthalmological complications, which is a significant clinical benefit. The infiltration solution has the advantage of a lower corticosteroid dose than previously reported dexamethasone-based perioperative regimens, thereby minimising any unwanted metabolic effects. The technique is advocated for the reduction of postoperative facial swelling in craniomaxillofacial surgical patients.

Differential expression of fibroblast growth factor receptors in human digital development suggests common pathogenesis in complex acrosyndactyly and craniosynostosis.

The Apert hand is characterized by metaphyseal fusions of the metacarpals and distal phalanges, symphalangism, and soft-tissue syndactyly. More subtle skeletal anomalies of the limb characterize Pfeiffer and Crouzon syndromes. Different mutations in the fibroblast growth factor receptor 2 (FGFR2) gene cause these syndromes, and offer the opportunity to relate genotype to phenotype. The expression of FGFR1 and of the Bek and KGFR isoforms of FGFR2 has, therefore, been studied in human hand development at 12 weeks by in situ hybridization. FGFRs are differentially expressed in the mesenchyme and skeletal elements during endochondral ossification of the developing human hand. KGFR expression characterizes the metaphyseal periosteum and interphalangeal joints. FGFR1 is preferentially expressed in the diaphyses, whereas FGFR2-Bek expression characterizes metaphyseal and diaphyseal elements, and the interdigital mesenchyme. Apert metaphyseal synostosis and symphalangism reflect KGFR expression, which has independently been quantitatively related ex vivo to the severity of clinical digital presentations in these syndromes. Studies in avian development implicate FGF signaling in preventing interdigital apoptosis and maintaining the interdigital mesenchyme. Herein is proposed that in human FGFR syndromes the balance of signaling by means of KGFR and Bek in digital development determines the clinical severity of soft-tissue and bony syndactyly.

Cooperation between actin-binding proteins of invasive Salmonella: SipA potentiates SipC nucleation and bundling of actin.

Pathogen-induced remodelling of the host cell actin cytoskeleton drives internalization of invasive Salmonella by non-phagocytic intestinal epithelial cells. Two Salmonella actin-binding proteins are involved in internalization: SipC is essential for the process, while SipA enhances its efficiency. Using purified SipC and SipA proteins in in vitro assays of actin dynamics and F-actin bundling, we demonstrate that SipA stimulates substantially SipC-mediated nucleation of actin polymerization. SipA additionally enhances SipC-mediated F-actin bundling, and SipC-SipA collaboration generates stable networks of F-actin bundles. The data show that bacterial SipC and SipA cooperate to direct efficient modulation of actin dynamics, independently of host cell proteins. The ability of SipA to enhance SipC-induced reorganization of the actin cytoskeleton in vivo was confirmed using semi-permeabilized cultured mammalian cells.

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.

Surveillance neuroimaging in childhood intracranial ependymoma: how effective, how often, and for how long?

OBJECT: The authors examined images obtained in 52 children with intracranial ependymomas to determine risk factors for tumor recurrence and to assess the impact of surveillance imaging on patient outcome. METHODS: Data obtained in all children with intracranial ependymomas were prospectively entered into a database from January 1987 to June 2000. The imaging and clinical details in all patients were reviewed. Fifty-two children with histologically proven intracranial ependymomas were treated at the authors' institution; recurrences developed in 28 (54%) of them, with a median time from surgery to first recurrence of 14.5 months (range 3-65 months). Of these tumor recurrences, 43% were asymptomatic and were noted on surveillance imaging. Seventeen children died, all of whom had recurrences. Incomplete excision of the primary tumor was significantly associated with reduced time to recurrence (p = 0.0144) and time to death (p = 0.0472). The age of the patient, location of the primary tumor, histological findings, and the presence or absence of spinal metastases on preoperative imaging were not significantly associated with outcome. The risk of death at any given time was 12-fold greater in patients in whom a recurrence was identified due to symptoms rather than on surveillance images (p = 0.016). CONCLUSIONS: Recurrent childhood ependymoma has a poor prognosis. The extent of the initial local tumor resection is the factor most closely associated with outcome. Surveillance imaging reveals a substantial number of asymptomatic recurrences, and survival appears to be improved in these patients compared with those identified by symptoms. The improvement in survival is thought to be greater than that expected just from earlier diagnosis.

Membrane fusion activity of purified SipB, a Salmonella surface protein essential for mammalian cell invasion.

An early event in Salmonella infection is the invasion of non-phagocytic intestinal epithelial cells. The pathogen is taken up by macropinocytosis, induced by contact-dependent delivery of bacterial proteins that subvert signalling pathways and promote cytoskeletal rearrangement. SipB, a Salmonella protein required for delivery and invasion, was shown to localize to the cell surface of bacteria invading mammalian target cells and to fractionate with outer membrane proteins. To investigate the properties of SipB, we purified the native full-length protein following expression in recombinant Escherichia coli. Purified SipB assembled into hexamers via an N-terminal protease-resistant domain predicted to form a trimeric coiled coil, reminiscent of viral envelope proteins that direct homotypic membrane fusion. The SipB protein integrated into both mammalian cell membranes and phospholipid vesicles without disturbing bilayer integrity, and it induced liposomal fusion that was optimal at neutral pH and influenced by membrane lipid composition. SipB directed heterotypic fusion, allowing delivery of contents from E. coli-derived liposomes into the cytosol of living mammalian cells.

Management of choroid plexus tumours in children: 20 years experience at a single neurosurgical centre.

OBJECTIVE: Tumours of the choroid plexus are rare tumours of neuro-ectodermal origin, accounting for less than 1% of all intracranial tumours. Most cases present in children less than 2 years of age. While choroid plexus carcinomas (CPC) are reported to have an extremely poor prognosis, choroid plexus papillomas (CPP) are generally regarded as benign tumours with a very favourable long-term outcome. Management dilemmas are associated with the choice of surgical procedure, tumour vascularity, the treatment of hydrocephalus and the value of adjuvant therapy. The objective of this study was to review our experience with this rare tumour over a 20-year period. METHODS: Patients were identified from the Great Ormond Street Neurosurgical Brain Tumour Database. Over a 20-year period (1979-1999), 34 children were identified with a choroid plexus tumour. There were 25 cases of CPP and 9 cases of CPC. A retrospective review of case notes, radiological imaging, operation reports and pathology was performed. RESULTS: The median age at presentation was 17 months (1-138) for CPP and 13 months (2-102) for CPC. There was no sex difference for CPP. However, 8 of the 9 CPCs were male (89%). A complete surgical resection was achieved in all 25 cases of CPP and in 3 cases of CPC (33%). The median survival for CPPs was 75.5 months (2-228), with a median follow-up of 73.5 months (2-228). The median survival for CPCs was 6 months (1-90), with a median follow-up of 6 months (1-90). CONCLUSION: With modern neurosurgical practise, a cure should be the aim for all children with CPP. There is no evidence that adjuvant therapy has any role in the primary management of these children. However, CPC still has an extremely poor prognosis, and the efficacy of adjuvant therapy remains to be established.

Growth hormone treatment of children with brain tumors and risk of tumor recurrence.

GH is increasingly used for treatment of children and adults. It is mitogenic, however, and there is therefore concern about its safety, especially when used to treat cancer patients who have become GH deficient after cranial radiotherapy. We followed 180 children with brain tumors attending three large hospitals in the United Kingdom and treated with GH during 1965-1996, and 891 children with brain tumors at these hospitals who received radiotherapy but not GH. Thirty-five first recurrences occurred in the GH-treated children and 434 in the untreated children. The relative risk of first recurrence in GH-treated compared with untreated patients, adjusted for potentially confounding prognostic variables, was decreased (0. 6; 95% confidence interval, 0.4-0.9) as was the relative risk of mortality (0.5; 95% confidence interval, 0.3-0.8). There was no significant trend in relative risk of recurrence with cumulative time for which GH treatment had been given or with time elapsed since this treatment started. The relative risk of mortality increased significantly with time since first GH treatment. The results, based on much larger numbers than previous studies, suggest that GH does not increase the risk of recurrence of childhood brain tumors, although the rising trend in mortality relative risks with longer follow-up indicates the need for continued surveillance.

Intracranial neoplasms in the first year of life: results of a second cohort of patients from a single institution.

The objective of this study was to describe the presentation and outcome of children with intracranial tumours under 1 year of age, and to compare the results with a previous cohort from the same paediatric neurosurgical unit. It is a retrospective review of all children under 1 year of age presenting with intracranial tumours between 1982 and 1997, with follow-up data from a multidisciplinary paediatric neuro-oncology clinic. Seventy-five children were diagnosed during the period of study. Overall survival at 5 years was 56% (31 of 55 eligible children), half of whom are in mainstream education. Earlier diagnosis and a dramatic reduction in peri-operative mortality compared to our previous cohort account for the improvements in the results of treatment for these children whose care can only be properly managed in a specialized paediatric oncology centre.

Direct nucleation and bundling of actin by the SipC protein of invasive Salmonella.

Salmonella causes severe gastroenteritis in humans, entering non-phagocytic cells to initiate intracellular replication. Bacterial engulfment occurs by macropinocytosis, which is dependent upon nucleation of host cell actin polymerization and condensation ('bundling') of actin filaments into cables. This is stimulated by contact-induced delivery of an array of bacterial effector proteins, including the four Sips (Salmonella invasion proteins). Here we show in vitro that SipC bundles actin filaments independently of host cell components, a previously unknown pathogen activity. Bundling is directed by the SipC N-terminal domain, while additionally the C-terminal domain nucleates actin polymerization, an activity so far known only in eukaryotic proteins. The ability of SipC to cause actin condensation and cytoskeletal rearrangements was confirmed in vivo by microinjection into cultured cells, although as SipC associates with lipid bilayers it is possible that these activities are normally directed from the host cell membrane. The data suggest a novel mechanism by which a pathogen directly modulates the cytoskeletal architecture of mammalian target cells.

The feet in Apert's syndrome.

Apert's syndrome (acrocephalosyndactyly type 1) is characterised by anomalies of the cranium, hands, and feet. The cranial and hand anomalies have been investigated, and the management of these is well established. In contrast, the anomalies affecting the feet and their management has previously received little attention. Forty-three children with Apert's syndrome underwent investigation of the anomalies affecting their feet. This consisted of history, clinical examination, and where possible, radiographic examination to establish the anomalies present, how these altered during development, and their clinical significance. The conclusion of the study is that there are widespread anomalies of the feet, with defects including both predictable dysmorphic changes and progressive fusions of the skeletal components during skeletal maturity. These fusions and their effect on growth combine to produce increasing deformity during childhood. The clinical significance of the anomalies is that walking is often delayed, and the increasing deformity results in difficulty obtaining footwear. This is the most common reason for surgery to the feet being undertaken during childhood to improve the shape of the feet to facilitate the provision of footwear. The unexpectedly high incidence of surgery in this study suggests that the management of foot deformities may require surgery more frequently than current literature would suggest.

Acromelic frontonasal dysostosis.

We report on 3 male and 2 female infants with acromelic frontonasal dysostosis. All 5 had a frontonasal malformation of the face and nasal clefting associated with striking symmetrical preaxial polysyndactyly of the feet and variable tibial hypoplasia. In contrast, the upper limbs were normal. This rare variant of frontonasal dysplasia may represent a distinct autosomal-recessive disorder. We suggest that the molecular basis of this condition may be a perturbation of the Sonic Hedgehog (SHH) signalling pathway, which plays an important part in the development of the midline central nervous system/craniofacial region and the limbs.