Aneurysmal bone cysts of the cranium in children. Report of three cases and brief review of the literature.

Aneurysmal bone cysts (ABCs) of the cranium in children are rare, with only 3 to 6% of cases occurring in this anatomical location. Consequently, not much is known about ABCs and the most effective modality of treatment. The authors present the cases of three patients with ABCs and discuss the origin, pathogenesis, clinical presentation, pathological features, and imaging characteristics of these lesions. Furthermore the authors review the literature to find out the current treatment options for these lesions.

Risk factors for developing epilepsy after craniotomy in children.

INTRODUCTION: We performed a retrospective analysis of children undergoing supratentorial craniotomy, attempting to identify possible risk factors for postoperative epilepsy and the need for prophylactic anticonvulsant therapy. MATERIALS AND METHODS: We analysed 107 consecutive patients (55% males) who had supratentorial craniotomy for a variety of diagnoses (tumours, trauma, infection, vascular malformations and others) during 1995-1999. Mean age at operation was 89 months (range: 1-180 months). Patients who presented with epilepsy were excluded. Postoperative epilepsy was considered present if patients required systematic pharmacological treatment, at a minimum follow-up of 6 months. Linear regression was used to analyse the effect of sex, anticonvulsant prophylaxis, duration of operation, closure of dura, postoperative infection, the diagnosis, anatomical region of brain affected, operation type (craniotomy/craniectomy) and the need for brain resection. RESULTS: Prophylactic anticonvulsants were given to 52% of the patients; 97% had craniotomy; in five patients, the dura was left open; in 33%, some kind of brain tissue resection had been performed; two patients (1.8%) developed postoperative infection; one patient died. Only 13 patients (12%) developed postoperative epilepsy. The only two factors with statistical significance were female sex (p=0.045) and the absence of dural closure (p=0.001). All other factors were not significant (p>0.258). CONCLUSIONS: Postoperative epilepsy after supratentorial craniotomy is uncommon in children, incidence being 12%. The administration of prophylactic anticonvulsants does not appear to influence the risk of epilepsy. Surprisingly, females have statistically higher risk. Lack of dural closure has higher risk of epilepsy, but this may reflect the type of pathology.

Familial Dandy-Walker syndrome: a case report supporting an autosomal inheritance.

INTRODUCTION: We report an isolated pedigree in which a consanguineous couple had twin sons with Dandy-Walker malformation (DWM). The mother is similarly affected with the disorder. DISCUSSION: DWM is an abnormality of the central nervous system, which leads to hydrocephalus and is associated with other abnormalities. CONCLUSION: Inheritance of the disorder remains controversial, with the majority perceived to be sporadic cases. This report suggests an autosomal inheritance.

Management of pyopagus conjoined twins.

INTRODUCTION: Approximately 18% of conjoined twins (1 in 200,000 live births) are joined at the sacrum ("pyopagus"). As the joined structures are not life-threatening, there is generally a good prognosis, with time for investigation and planning of operative separation. CASE REPORT: This paper reports on the management of pyopagus twin girls, the first in the UK delivered at 36 weeks by Caesarean section. The diagnosis had been made by ultrasound at 12 weeks' and confirmed by MRI scan at 26 weeks' gestation. Each twin had wasting and weakness below one knee, but no deficit in the other leg. The perineum had two urethras but only one anus. One infant had a colostomy in the immediate neonatal period. With appropriate further imaging, surgery was planned in two stages. First, a balloon expander was inserted in the bridging area. At 3 months of age a team comprising Plastic, Paediatric and Neurosurgeons undertook the definitive separation. DISCUSSION: Details of the multidisciplinary planning, operative separation and follow-up of these two children will be discussed.

Maxillary volume growth in childhood.

Nasomaxillary abnormalities in form, position, and development in children are often prominent features of craniosynostosis, and in particular, craniofacial dysostosis. While attempting to quantitatively assess the volumetric maxillary deficiency in these patients, it became apparent that there was no "normal" reference range for maxillary volumes throughout childhood that could be used for comparison. The aim of this study was to generate a model for measuring maxillary volume and subsequent changes throughout childhood. The technique of segmentation was applied to magnetic resonance images obtained in 55 healthy children (30 boys, 25 girls), aged 1 month to 184 months (15.33 years). Maxillary volumes were plotted against age for boys and girls to create a model for normal maxillary growth during the first 15 years of life. Maxillary volumes were larger in boys at all ages. However, the pattern of maxillary growth in boys and girls was similar and could be divided into three periods, each lasting approximately 5 years. During the first 5 years of life, there is a steady increase in maxillary volume, at the end of which the maxilla has reached 53 percent of the volume recorded at 15 years. There is an accelerated rate of growth between 5 and 11 years, which corresponds to the development and eruption of the permanent dentition. Thereafter, until the age of 15 years, the rate of growth of the maxilla plateaus. Maxillary volume in the first 12 months of life is, on average, 29 cm3 in boys and 25 cm3 in girls. By 15 years of age, it has increased to an average of 73.0 cm3 in boys and 59.4 cm3 in girls (an increase by a factor of 2.5 in boys and 2.4 in girls). The difference between the two sexes is statistically significant for the entire series (boys: mean maxillary volume = 56.55 cm3, SD = 24.61; girls: mean maxillary volume = 40.68, SD = 17.69, p = 0.009, one-way analysis of variance).

Maxillary volume growth in craniosynostosis.

Craniosynostosis, and in particular, craniofacial dysostosis, exhibits abnormalities of the nasomaxillary complex in form, position, and development. The aim of this study was to quantitatively assess the volumetric maxillary abnormality in patients at the time of initial diagnosis of craniosynostosis and to make comparisons with a "normal" reference range for maxillary volumes throughout childhood. The technique of segmentation was applied to preoperative computed tomographic head scans obtained in 31 children (14 boys, 17 girls), between 1 and 34 months of age (mean, 11.06 months), who underwent cranial expansion surgery for craniosynostosis affecting the coronal suture complex. Maxillary volumes were plotted against age for the first 3 years of life and were compared with a healthy population. There was no statistical difference between the two sexes for mean maxillary volume. The mean maxillary volumes for the entire group were statistically smaller than the norm (p = 0.046, linear regression with age as a covariable), but there was no statistical difference among the four different groups of coronal synostosis (unilateral coronal, nonsyndromic bilateral coronal, nonsyndromic complex pansynostosis, syndromic bilateral coronal synostosis) (p = 0.407, one-way analysis of variance). On graphic data analysis, the maxillary volume was smaller than the norm in craniosynostotic children who presented in the first few months of life. However, by 7 months of age in nonsyndromic bilateral coronal synostosis and by 17 months of age in syndromic bilateral coronal synostosis, the maxillary volumes had increased toward the norm. This implies that the effect of the craniosynostotic process on the midface structures is present from birth and parallels the effect on the cranial vault sutures.

Influence of shunt type on ventricular volume changes in children with hydrocephalus.

OBJECT: The goal of this study was twofold: to investigate the change in ventricular volume in children with hydrocephalus in response to shunt placement and to assess the effects of two different valve types (Medium Pressure [MP] cylindrical valve and Delta [model 1.5] valve). METHODS: Ventricular volume was measured using segmentation techniques on computerized tomography scans and magnetic resonance images obtained in 40 children with hydrocephalus who ranged in age from 4 days to 16 years. Imaging was performed preoperatively and at 5 days and 3, 6, and 12 months postoperatively. The results were compared with measurements obtained in 71 healthy children ranging in age from 1 month to 15 years. Each ventricular volume that was measured was divided by the corresponding sex and age-related mean normal volume to calculate the "x normal" ventricular volume, indicating how many times larger than normal the ventricle was. The mean preoperative ventricular volume was 232 cm3 (range 50-992 cm3). The mean postoperative volumes were 147, 102, 68, and 61 cm3 at 5 days and at 3, 6, and 12 months posttreatment, respectively. The mean preoperative x normal ventricular volume was 14.5 (range 2.2-141.7), and the mean postoperative x normal volumes were 7.9, 5.6, 3.5, and 2.9 at 5 days and 3, 6, and 12 months postimplantation, respectively. The rate of volume reduction was consistently higher in patients who received the MP valve in comparison with those who received the Delta valve, both for new shunt insertions and for shunt revisions. The difference between the two valve groups did not reach statistical significance. Two patients in whom ventricular volumes increased during the study period experienced shunt obstruction at a later time. CONCLUSIONS: Preoperative ventricular volume in children with hydrocephalus can be up to 14 times greater than normal. In response to shunt placement, the ventricular volume continues to fall during the first 6 months after operation. The effect is more profound in children who receive the MP valve than in those who receive the Delta valve, although in this study the authors did not demonstrate statistical significance in the difference between the two valves. Nevertheless, this may indicate that the MP valve produces overdrainage in comparison with the Delta valve, even within the first few months after insertion. There is some indication that sequential ventricular volume measurement may be used to identify impending shunt failure.

Normal changes in orbital volume during childhood.

OBJECT: The aim of this study was to construct a model of changes in orbital volume that occur throughout childhood from the age of 1 month to 15 years, which could be used for comparative studies of disease states affecting orbital growth. METHODS: Using the procedure of segmentation on magnetic resonance images obtained in 67 healthy children, orbital volume was measured and plotted against age. During the first few months of life left orbital volume is on average 15 cm3 in male and 13 cm3 in female infants; these volumes increase to 26 cm3 and 24 cm3, respectively, by the time the child reaches 15 years of age. During the first few months of life right orbital volume is on average 16 cm3 in male and 13 cm3 in female infants; these volumes increase to 27 cm3 and 25 cm3, respectively, by the time the child is 15 years old. This represents an overall increase in orbital volume by a factor of 1.7 in boys and 1.8 in girls. By the time the child has reached 5 years of age, the orbital volume for both right and left sides has reached on average 77% of the volume seen at 15 years in both sexes. The differences between the two sides are not statistically significant for either sex. The change in orbital volume that is associated with age in general displays a linear pattern. Throughout childhood, orbital volumes are larger in boys than in girls, but share a similar growth pattern. The difference between the two sexes tends toward statistical significance during the first 5 years of life (left orbit p = 0.1, right orbit p = 0.04). CONCLUSIONS: During early childhood, orbital volume increases in a linear fashion, achieving a significant proportion of its final growth by the time the child is 5 years old.

Changes in orbital volume during childhood in cases of craniosynostosis.

OBJECT: Controversy remains concerning the timing of frontoorbital advancement (FOA) surgery performed for craniosynostosis. Reduced orbital volume and degree of exorbitism are often cited as reasons for early surgical intervention. To date, however, little attention has been given to orbital volume and its changes during the first few years of life as an indicator of orbital growth in children with craniosynostosis. Knowledge of orbital volume and growth patterns in individuals with craniosynostosis and those with normal cranial structures will enable surgeons to refine both the type and timing of surgical intervention required, thus obtaining the optimum outcome for their patients. METHODS: Using the procedure of segmentation, orbital volumes in 50 children with various forms of craniosynostosis were measured on preoperative computerized tomography scans. Changes in average volume that occur with increasing age were calculated and compared with a model of normal orbital volume growth. At presentation the children with craniosynostosis ranged in age from 1 to 29 months, with 82% of them within the 1st year of life. Several interesting observations emerged from this study. Excluding patients with unilateral coronal synostosis, there was no difference between orbital volumes measured on the right and left sides, allowing mean orbital volume measurements to be used for comparative purposes. Although children with craniosynostosis begin life with significantly smaller orbital volumes, overall normal mean volumes for both sexes are attained by 13 months of age, with volumes approaching normal by 6 months of age in male infants and by 8 months of age in female infants. Changes in orbital volume associated with age generally appear to be similar in most forms of craniosynostosis. There appears to be no significant difference in changes in orbital volume between children with syndromic or nonsyndromic forms of bicoronal synostosis. Orbital volume is significantly reduced on the ipsilateral affected side in cases of unicoronal synostosis in comparison with the contalateral side, but it is not significantly lower than that of normal. Finally, FOA surgery appears to restore normal growth of orbital volume. CONCLUSIONS: The results of this study indicate that the underlying mechanism leading to craniosynostosis and restriction of orbital volume "burns out" and begins to lose its major effects within the first few months of life. It would appear that FOA surgery should be delayed until the end of the second half of the 1st year of life, thus maximizing the effects of accelerated normal orbital growth and reducing the risks of relapse.