Richard Hayward

Intracranial Pressure in Single-Suture Craniosynostosis

The indications for surgical correction of craniosynostosis in which there is involvement of only one of the cranial vault sutures have traditionally been based upon the cosmetic merits of the deformity alone. Whilst it is now appreciated that intracranial hypertension is commonly associated with the more complex forms of craniosynostosis, this aspect has not previously been addressed in detail among cases of single-suture craniosynostosis. This retrospective study reports our experience of overnight subdural intracranial pressure monitoring in 74 children with premature closure of a single cranial suture. A single coronal suture was involved in 37 patients, the sagittal suture in 25 and the metopic suture in 12. Intracranial pressure was raised in 13 (17%), borderline in 28 (38%) and normal in 33 (45%). Elevated intracranial pressure was seen more commonly where a midline suture was involved (sagittal or metopic) than when a single coronal suture was fused. We conclude that intracranial hypertension occurs in a significant proportion of children with single-suture craniosynostosis and suggest that this factor should be borne in mind during the initial assessment of these children so as to enable timely intervention where required and appropriate counselling of parents.

The Long-Term Outlook for Hydrocephalus in Childhood

Despite the fact that ventriculoperitoneal shunt insertion is the most commonly performed surgical operation in the pediatric neurosurgeons repertoire, there is a surprising paucity of long-term outcome studies for these patients detailing either the complication rate over a predetermined time period or more importantly their intellectual outcome. The aims of this study, therefore, were to determine the 10-year outcome in a cohort of 155 children with shunted hydrocephalus, both in terms of the number and time sequence of shunt complications and also the long-term academic (schooling) outcome of these individuals. This was a cohort study of 155 hydrocephalic children who underwent first-time ventriculoperitoneal shunt insertion between the years 1978 and 1983, who were then followed up on an annual outpatient basis for a period of 10 years or until death. Their academic records and the surgical morbidity and mortality encountered over the 10-year study period were used as the main outcome measures. For those children surviving until schoolage, 59% were able to attend a normal school. The academic outlook for those children with hydrocephalus secondary to infection (postmeningitic) or intraventricular hemorrhage was less favorable with 52 and 60% requiring special schooling compared to those children with congenital hydrocephalus (29%; p = 0.036). 44% (68/155) of patients in this cohort did not require a shunt revision. The commonest reasons for shunt revision were blockage (49%) and infection (19%) which predominantly occurred within the first year of their original shunt procedure. Overall the infection rate was 12% (44/380 procedures). Furthermore an increased incidence of shunt infection was noted in those under 6 months old (p = 0.040). There was an 11 % mortality during the 10-year follow-up period for those with nontumor-related hydrocephalus.

The effectiveness of papilledema as an indicator of raised intracranial pressure in children with craniosynostosis.

Craniosynostosis management partially depends on the detection and treatment of elevated intracranial pressure (ICP). Examination for papilledema is considered to be the most reliable screening method for identifying raised ICP, but its effectiveness has not been defined. One hundred and twenty-two children with craniosynostosis who underwent funduscopic examinations and then Camino ICP monitoring were studied. All eye examinations were performed by an ophthalmologist after pharmacological pupillary dilation. Fifteen patients (12%) had papilledema. Subsequent ICP monitoring showed that the median ICP was 12.7 mm Hg, with 41 patients (34%) having elevated ICPs (> 15 mm Hg). Those with papilledema had higher ICPs (17.5 +/- 3.2 versus 12.7 +/- 5.5 mm Hg), were older (5.9 +/- 4.7 versus 1.9 +/- 2.6 years), and were more likely to have craniofacial syndromes (73 versus 41%) than those without papilledema (P < 0.05). Patients with both elevated ICPs and papilledema were older (5.9 +/- 4.7 versus 1.6 +/- 1.4 years) and more likely to have multiple-suture synostosis (92 versus 61%) than those with elevated ICPs and no papilledema (P < 0.05). The presence of papilledema was a specific (98%) indicator of raised ICP, but its sensitivity was age-dependent. It was 100% sensitive in children older than 8 years, but it indicated elevated ICP in only 22% of younger patients. These results suggest that ICP monitoring to document elevated ICP is unnecessary in children older than 8 years who have detailed ophthalmological examinations. In the younger child, the presence of papilledema reliably indicates elevated ICP but its absence does not rule out elevated ICP; formal ICP measurement has a greater role in detecting elevated ICP in these patients.

Mutation Analysis and Embryonic Expression of the HLXB9 Currarino Syndrome Gene

The HLXB9 homeobox gene was recently identified as a locus for autosomal dominant Currarino syndrome, also known as hereditary sacral agenesis (HSA). This gene specifies a 403-amino acid protein containing a homeodomain preceded by a very highly conserved 82-amino acid domain of unknown function; the remainder of the protein is not well conserved. Here we report an extensive mutation survey that has identified mutations in the HLXB9 gene in 20 of 21 patients tested with familial Currarino syndrome. Mutations were also detected in two of seven sporadic Currarino syndrome patients; the remainder could be explained by undetected mosaicism for an HLXB9 mutation or by genetic heterogeneity in the sporadic patients. Of the mutations identified in the 22 index patients, 19 were intragenic and included 11 mutations that could lead to the introduction of a premature termination codon. The other eight mutations were missense mutations that were significantly clustered in the homeodomain, resulting, in each patient, in nonconservative substitution of a highly conserved amino acid. All of the intragenic mutations were associated with comparable phenotypes. The only genotype-phenotype correlation appeared to be the occurrence of developmental delay in the case of three patients with microdeletions. HLXB9 expression was analyzed during early human development in a period spanning Carnegie stages 12-21. Signal was detected in the basal plate of the spinal cord and hindbrain and in the pharynx, esophagus, stomach, and pancreas. Significant spatial and temporal expression differences were evident when compared with expression of the mouse Hlxb9 gene, which may partly explain the significant human-mouse differences in mutant phenotype.

Subdural intracranial pressure monitoring in craniosynostosis: its role in surgical management.

In the management of craniosynostosis subdural intracranial pressure (ICP) monitoring has proved a useful and safe means of identifying those children with raised ICP who are at risk from its long-term sequelae and who would benefit from early surgical intervention. Overnight subdural ICP recordings have been obtained in 136 unoperated cases of craniosynostosis. Fifteen patients were studied both before and after cranial vault remodelling procedures. ICP was raised (>15 mmHg) in 35%, borderline (10–15 mmHg) in 27% and normal (<10 mmHg) in 27% of cases. Raised ICP was present in 28/53 of the syndromic craniofacial dysostosis cases and in 20/83 non-syndromic craniosynostosis cases investigated (P<0.001). Raised mean ICP and periodic plateaux of sustained ICP during sleep were particularly associated with the syndromic cases. Of the 15 patients studied following cranial vault surgery, 9 showed a reduction in ICP, 3 were unchanged and 3 had higher ICP postoperatively. The results of ICP monitoring can contribute significantly to formulating a rational and staged surgical management plan incorporating the need to normalise ICP and correct the frequently severe functional and cosmetic consequences of these disorders.

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.

The beaten copper cranium: a correlation between intracranial pressure, cranial radiographs, and computed tomographic scans in children with craniosynostosis.

OBJECTIVE The beaten copper appearance of the cranium, as well as other cranial radiographic and computed tomographic findings in children with craniosynostosis, is often interpreted by clinicians as evidence of elevated intracranial pressure (ICP). However, a correlation between radiological findings and ICP measurements has not been previously demonstrated, and their usefulness in detecting elevated ICP has not been defined. METHODS To address those issues, 123 children with craniosynostosis who had cranial radiographs and ICP monitoring were studied. To assess the specificity of certain radiological findings to patients with craniosynostosis, cranial radiographs of patients with craniosynostosis were compared to those of age- and sex-matched controls. In patients with craniosynostosis, findings on cranial radiographs were compared to computed tomographic scans of the brain. Radiographic findings were then correlated with ICP measurements obtained while the patient was sleeping, which was measured using a Camino fiberoptic ICP monitor (Camino Laboratories, San Diego, CA). All radiographs were independently analyzed by two radiologists who were blinded to clinical and ICP data. RESULTS A diffuse beaten copper pattern, erosion of the dorsum sellar, and suture diastasis were seen more commonly in patients with craniosynostosis than in controls (P < 0.05), but the presence of the beaten copper pattern was no more common in children with craniosynostosis. ICP was greater when a diffuse beaten copper pattern, dorsum sellar erosion, suture diastasis, or narrowing of basal cisterns was present (P < 0.05). CONCLUSION Although this study demonstrates that some cranial radiographic and computed tomographic findings do correlate with elevated ICP, the sensitivity of radiological methods for detecting elevated ICP is universally low and they are not recommended to screen for elevated ICP in children with craniosynostosis.

Relationship between intracranial pressure and intracranial volume in craniosynostosis.

Abstract Premature fusion of cranial sutures in craniosynostosis has been thought to lead to craniostenosis, which in turn may lead to increased intracranial pressures. In 41 consecutive patients with craniosynostosis, intracranial pressure and intracranial volume were measured. Of the 41 patients, 38 (92.6%) had raised intracranial pressure but only 4 (9.7%) had a decreased skull volume. In the present study, there is no correlation between intracranial volume and intracranial pressure. This study confirms that the measurement of intracranial volume, a non invasive procedure, cannot be used to assess intracranial pressure and to avoid an invasive procedure.

Gain of 1q and loss of 22 are the most common changes detected by comparative genomic hybridisation in paediatric ependymoma

Ependymomas are the third most common brain tumour in the paediatric population. Although cytogenetic and molecular analyses have pinpointed deletions of chromosomes 6q, 17, and 22 in a subset of tumours, definitive patterns of genetic aberrations have not been determined. In the present study, we analysed 40 ependymomas from paediatric patients for genomic loss or gain using comparative genomic hybridisation (CGH). Eighteen of the tumours (45%) had no detectable regions of imbalance. In the remaining cases, the most common copy number aberrations were loss of 22 (25% of tumours) and gain of 1q (20%). Three regions of high copy number amplification were noted at 1q24‐31 (three cases), 8q21‐23 (two cases), and 9p (one case). Although there was no association with the loss or gain of any chromosome arm or with benign versus anaplastic histologic characteristics, the incidence of gain of 7q and 9p and loss of 17 and 22 was significantly higher in recurrent versus primary tumours. This study has identified a number of chromosomal regions that may contain candidate genes involved in the development of different subgroups of ependymoma.

Speech, language, and cognitive development in children with isolated sagittal synostosis

This study investigated the occurrence, nature, and severity of speech, language, and cognitive impairment in 76 children (61 males, 15 females) with isolated sagittal synostosis (ISS) aged 9 months to 15 years 7 months. There was no increased prevalence of global cognitive impairment in the group but there was a high prevalence rate of speech and/or language impairment with 28 (37%) displaying impairment of whom 20 (71%) had moderate or severe impairments that fulfilled the criteria for specific impairments. Prevalence rates were only increased for children over two years of age. Expressive language impairment occurred most frequently. Raised intracranial pressure, peri-neonatal risk factors, otitis media, or being operated were not associated with impairment. Surgery at a later age and a family history of speech and language impairment were both associated with impairments but numbers were small. The findings suggest that children with ISS are at an increased risk of developing speech and language impairment.