Tuesday, July 31, 2007

Chiari-II malformation: a biometric analysis

Tsai T, Bookstein FL, Levey E, Kinsman SL. Chiari-II malformation: a biometric analysis. European Journal of Pediatric Surgery. 2002 Dec;12 Suppl 1:S12-8.

INTRODUCTION: Chiari-II malformation is a complex set of anatomic abnormalities of the posterior fossa, brainstem, and cerebellum seen in myelomeningocele. Previous studies have tried to understand this condition and its clinical consequences by studying a few fixed anatomic landmarks as dependent variables and clinical symptoms as outcome variables. These studies have led to conflicting and limited results. As a first step towards a more comprehensive study of the structural-functional relationships in Chiari-II malformation, we undertook a biometric case-series analysis of a group of individuals with MMC, using both traditional methods to study size, and thin-plate spline methodology to study shape.

MATERIALS AND METHODS: The traditional analysis was a retrospective, randomly obtained case-series of 25 individuals with myelomeningocele and Chiari-II malformation. MRIs were digitized for biometric analysis of the component structures and compared to 25 controls. Landmarks on the digitized images were measured using Scion Image. Data were statistically analyzed using SPSS. The thin-plate spline analysis used a subset of these individuals (n = 14). Landmarks on digitized MRIs were identified and marked with TPSDig software. Landmark data was then imported into Splus to generate a series of shape variables. Statistical analysis using Splus was then undertaken. RESULTS: Traditional analysis revealed relationships between vermian herniation and pontomedullary junction position (p < 0.05) as well as between the height (and overall size) of the posterior fossa and degree of vermian herniation (p < 0.05). The degree of brainstem herniation/elongation did not correlate with the degree of vermian herniation. The shape analysis revealed that there is as much shape variability within the group of Chiari-II patients as there is between this group and unaffected controls. Thin-plate spline analysis shows that the position of the caudal-most aspect of the vermis is the point of greatest brain rearrangement; likewise, the opisthion is the point of greatest bony rearrangement. Partial least-squares analysis shows that in Chiari-II patients, a strong correlation (r = 0.821) exists between the extent to which the brain is warped (specifically, in regard to vermian descent) and the extent to which the bone is warped (specifically, in regard to the displacement of the opisthion) (p < 0.05).

CONCLUSION: Traditional biometric analysis of size confirms that the degree of vermian herniation and cervicomedullary junction herniation are independent variables in Chiari-II malformation. Posterior fossa size is an important factor in explaining the variability of vermian herniation. The relationship between IPN position and vermian herniation suggests the possibility of a common etiology. The phenomenon of cervicomedullary junction descent appears to be independent, suggesting a different etiology. Analysis of shape indicated that shape changes in bone and brain are related, and that the Chiari-II-associated abnormalities vary greatly in their degree of abnormality. The extreme morphological variability argues against the use of mean differences as a statistical technique in analyzing morphological abnormalities in the structures we investigated.

PMID: 12541208

Limbic tract anomalies in pediatric myelomeningocele and Chiari II malformation

Vachha B, Adams RC, Rollins NK. Limbic tract anomalies in pediatric myelomeningocele and Chiari II malformation: anatomic correlations with memory and learning--initial investigation. Radiology. 2006 Jul;240(1):194-202.

PURPOSE: To prospectively determine anomalies of limbic tracts and to describe the relationship between these anomalies, seen on diffusion-tensor magnetic resonance (MR) and fiber tract (FT) reconstruction images, and learning and memory in children with myelomeningocele (MM) and Chiari II malformation.

MATERIALS AND METHODS: The investigation was HIPAA compliant and approved by institutional review boards; informed consent was obtained. In seven male and six female patients (aged 6 months to 16 years) with MM and Chiari II malformation, diffusion-tensor imaging and FT reconstruction were performed. FT reconstruction was generated with fractional anisotropy continuous tracking algorithm and manually drawn regions of interest. Limbic tract abnormalities were assessed on FT reconstruction images by an experienced pediatric neuroradiologist blinded to results of cognitive testing. Nine patients met criteria for memory and learning testing by a trained cognitive neuroscientist blinded to MR results. Exact Wilcoxon rank sum test was used to compare performance with learning and memory tasks in two groups.

RESULTS: Eleven of 13 patients had defects within fornices and/or cingulum; three patients had aberrant fibers of cingulum. In nine patients, six had deficits in general memory; four, in learning; and four, in both. Atresia or hypoplasia of crura and body of fornices was noted in six patients with memory deficits and four patients with learning deficits. Five of six patients with memory deficits and three of four with learning deficits had hypoplasia or atresia of cingulum. Exact Wilcoxon rank sum test demonstrated significantly poorer performance for nonverbal immediate recall tasks in patients with anomalies of the fornix compared with those without (P = .04, exact two-tailed test).

CONCLUSION: Diffusion-tensor and FT reconstruction images revealed that limbic fiber abnormalities were common in patients with MM and Chiari II malformation. Nonverbal immediate recall task performance appeared to be related to abnormalities of the fornix.

PMID: 16793979

Saccades in children with spina bifida and Chiari type II malformation

Salman MS, Sharpe JA, Eizenman M, Lillakas L, To T, Westall C, Steinbach MJ, Dennis M. Saccades in children with spina bifida and Chiari type II malformation.
Neurology. 2005 Jun 28;64(12):2098-101.

BACKGROUND: Saccades are essential for optimal visual function. Chiari type II malformation (CII) is a congenital anomaly of the cerebellum and brainstem, associated with spina bifida.

OBJECTIVE: To investigate the effects of CII on saccades and correlate saccadic parameters with brain MRI measurements.

METHODS: Saccades were recorded in 21 participants with CII, aged 8 to 19, using an infrared eye tracker. Thirty-nine typically developing children served as controls. Participants made saccades to horizontal and vertical target steps. Nineteen participants with CII had MRI. Regression analyses were used to investigate the effects of spinal lesion level, number of shunt revisions, presence of nystagmus, and midsagittal MRI measurements on saccades.

RESULTS: Saccadic amplitude gains, asymptotic peak velocities, and latencies did not differ between the control and CII groups (p > 0.01). No significant differences were found between saccadic gains, asymptotic peak velocities or latencies, and spinal lesion level, number of shunt revisions, presence of nystagmus, or MRI measurements.

CONCLUSIONS: Saccades were normal in most participants with Chiari II malformation (CII). Neural coding of saccades is robust and is typically not affected by the anatomic deformity of CII.

PMID: 15985580

Degree of tectal beaking correlates to the presence of nystagmus in children with Chiari II malformation

Tubbs RS, Soleau S, Custis J, Wellons JC, Blount JP, Oakes WJ. Degree of tectal beaking correlates to the presence of nystagmus in children with Chiari II malformation. Child's Nervous System. 2004 Jul;20(7):459-61. Epub 2004 Apr 2.

INTRODUCTION: Tectal beaking is a common finding in children born with a myelomeningocele. Quantitation of the presence or absence of this finding correlated with normal or abnormal eye movements is lacking in the medical literature.

MATERIALS AND METHODS: We prospectively evaluated 50 children in our multidisciplinary spina bifida clinic. Each child was observed for the presence or absence of nystagmus at rest or with extraocular movement. Grades of nystagmus and severity of tectal beaking (Types I-III) on MRI were then correlated.

RESULTS: Overwhelmingly, children with greater dysmorphology of the mesencephalic tectum were most likely to have nystagmus. Higher grades of nystagmus were associated with Type III tectal beaking.

CONCLUSIONS: We have demonstrated that there is a correlation between the presence and severity of nystagmus and the severity of tectal beaking and have quantified this association in patients with the Chiari II malformation. This information may act as a guide in predicting which children with the Chiari II malformation will have significant nystagmus. These data may aid the clinician in the interpretation of oculomotor abnormalities in this cohort of patients.

PMID: 15060837

Cerebral white matter and cognition in hydrocephalic children

Fletcher JM, Bohan TP, Brandt ME, Brookshire BL, Beaver SR, Francis DJ, Davidson KC, Thompson NM, Miner ME. Cerebral white matter and cognition in hydrocephalic children. Archives of Neurology. 1992 Aug;49(8):818-24.

Although children with hydrocephalus frequently show poor development of nonverbal cognitive skills relative to verbal skills, little is known about the neuropathologic correlates of these discrepancies. In this study, cerebral white-matter structures and lateral ventricles were measured from the magnetic resonance images of age-matched children with meningomyelocele, meningocele, and aqueductal stenosis and normal subjects. The volume of each lateral ventricle and the cross-sectional area of the corpus callosum and internal capsules were correlated with concurrent measures of verbal and nonverbal cognitive skills. The corpus callosum in the meningomyelocele and aqueductal stenosis groups was smaller. The lateral ventricles were larger, and the internal capsules were smaller, in all patient groups than in normal subjects. There were no differences in the size of the centra semiovale. Although verbal and nonverbal measures correlated positively with the size of the corpus callosum, the correlation was higher for nonverbal measures. Nonverbal measures correlated with the right, but not the left, lateral ventricle and with the area of the right and left internal capsules. Verbal measures correlated with the left, but not right, lateral ventricle and with the left, but not right, internal capsule. These results show a relationship between the corpus callosum and cognitive skills that is also influenced by hydrocephalus-related changes in the lateral ventricles and other cerebral white-matter tracts.

PMID: 1524514

Callosal anomalies in patients with spinal dysraphism: correlation of clinical and neuroimaging features with hemispheric abnormalities.

Kawamura T, Nishio S, Morioka T, Fukui K. Callosal anomalies in patients with spinal dysraphism: correlation of clinical and neuroimaging features with hemispheric abnormalities. Neurol Res. 2002 Jul;24(5):463-7.

Dysgenesis of the corpus callosum can occur in association with spinal dysraphic lesions. Clinical and neuroimaging features were reviewed in 23 patients (12 male, 11 female; mean age 11.3 years) with caudal spinal dysraphism (myeloschisis in eight, meningomyelocele in 10, and lumbosacral lipoma in five) to characterize types and degrees of callosal and other cerebral anomalies. T1- and T2-weighted magnetic resonance images were obtained, and the total midsagittal cross-sectional area of the corpus callosum was determined. The corpus callosum appeared normal in nine patients and was abnormal in 14. In five patients the corpus callosum was narrow, with all regions present; the cerebral hemispheres were hypoplastic. Two patients with dysgenesis of frontal, parietal, and occipital lobes had a small, partly agenetic corpus callosum. In the remaining seven patients the posterior third of the corpus callosum was absent or hypoplastic; six of them had ventriculomegaly that selectively affected the occipital horns (colpocephaly). All callosal anomalies were accompanied by hemispheric ones. This supports a disordered developmental relationship between the corpus callosum and the hemispheres as a cause. Spinal dysraphism can no longer be considered a single developmental abnormality, given the frequent association of other defects.

PMID: 12117315

Regional brain tissue composition in children with hydrocephalus. Relationships with cognitive development

Fletcher JM, McCauley SR, Brandt ME, Bohan TP, Kramer LA, Francis DJ, Thorstad K, Brookshire BL. Regional brain tissue composition in children with hydrocephalus. Relationships with cognitive development. Archives of Neurology. 1996 Jun;53(6):549-57.

OBJECTIVE: To determine whether children with shunted hydrocephalus show variations in regional brain tissue composition that relate to cognitive functions.

DESIGN: Nonequivalent control group.

PATIENTS AND METHODS: Magnetic resonance imaging (MRI) and cognitive skills assessments were obtained on 28 children, 6 to 9 years of age, with shunted hydrocephalus and 13 normal control subjects comparable in age, gender, ethnicity, and socioeconomic status. Three consecutive MRI slices below the vertex were segmented using a fuzzy clustering algorithm to separate pixels into gray matter, white matter, and cerebrospinal fluid (CSF) in quadrants representing left and right anterior and posterior brain regions. The cognitive skills assessments included the Wechsler Intelligence Scale for Children-Revised verbal and performance IQ scores, neuropsychological composites of language and visuospatial skills, a measure of visuomotor dexterity, and 2 measures of problem-solving abilities. The MRI data were analyzed in a group x tissue x hemisphere x region analysis of variance. Spearman rho correlations were computed within the hydrocephalus group between the MRI and cognitive measures.

RESULTS: Children with hydrocephalus showed reductions in overall gray matter percentages and corresponding increased CSF percentages that were more pronounced in posterior than anterior regions of both hemispheres. White matter percentages were reduced in children with hydrocephalus only in the left posterior quadrant. Correlations of posterior, but not anterior, CSF and gray matter percentages were significant with verbal and performance IQ scores and language, visuospatial, and visuomotor dexterity skills, but not with problem-solving abilities. Children with hydrocephalus who had proportionately greater posterior than anterior CSF percentages had significantly poorer visuomotor dexterity and visuospatial skills than did hydrocephalic children with proportionate CSF percentages.

CONCLUSION: Regional variations in brain tissue composition in children with shunted hydrocephalus correlate with a variety of cognitive and visuomotor functions.

PMID: 8660158

Interhemispheric transfer of visual, auditory, tactile, and visuomotor information in children with hydrocephalus and partial agenesis of the corpus c

Klaas PA, Hannay JH, Caroselli JS, Fletcher JM. Interhemispheric transfer of visual, auditory, tactile, and visuomotor information in children with hydrocephalus and partial agenesis of the corpus callosum. Journal of Clinical and Experimental Neuropsychology. 1999 Dec;21(6):837-50.

Interhemispheric transfer was examined in 13 normal controls and in 13 children with hydrocephalus and partial agenesis of the corpus callosum involving a missing splenium associated with spina bifida meningomyelocele and aqueductal stenosis. Children with hydrocephalus demonstrated greater left visual-field superiority for forms indicative of difficulty in interhemispheric transfer of visual information. Interhemispheric transfer time (ITT) was somewhat longer in the children with hydrocephalus, but neither the ITT task nor the dichotic listening and tactile naming tasks provided clear evidence of difficulties in callosal transfer. Sensory and perceptual control tasks revealed similar visual acuity and monotic word perception but larger 2-point discrimination thresholds and poorer tactile matching.

PMID: 10649538

Functioning of the corpus callosum in children with early hydrocephalus

Hannay HJ. Functioning of the corpus callosum in children with early hydrocephalus. Journal of the International Neuropsychological Society. 2000 Mar;6(3):351-61. Review.

The development and organization of the corpus callosum is described as well as the relationship between the timing of insults and the type of partial agenesis of the corpus callosum are discussed. Neuropathology and callosal damage associated with spina bifida meningomyelocele, aqueductal stenosis, and prematurity-IVH are outlined. Relationships between corpus callosum/whole brain ratios and cognitive functioning as well as interhemispheric transfer in children with these disorders are outlined. Shortcomings of current research and future directions are suggested.

PMID: 10824507

Language development in children with spina bifida

Fletcher JM, Barnes M, Dennis M. Language development in children with spina bifida. Seminars in Pediatric Neurology. 2002 Sep;9(3):201-8. Review.

Spina bifida meningomyelocele (SBM) is the most common severely disabling birth defect in North America. It is a disorder of the central nervous system that includes, in addition to the defining spinal dysraphism, congenital malformations of the cerebellum and corpus callosum that, along with hydrocephalus, produces a range of cognitive and motor difficulties, including language. In the language domain, many children with SBM demonstrate adequate development of language at the level of form and content (grammar and lexicon). However, most children with SBM experience significant difficulties in the construction of meaning and in pragmatic communication, both of which require flexible language processing in real time. Assessment and intervention should specifically attend to the development of meaning construction and semantic-pragmatic communication.

PMID: 12350041

Peripersonal spatial attention in children with spina bifida

Dennis M, Edelstein K, Frederick J, Copeland K, Francis D, Blaser SE, Kramer LA, Drake JM, Brandt M, Hetherington R, Fletcher JM. Peripersonal spatial attention in children with spina bifida: associations between horizontal and vertical line bisection and congenital malformations of the corpus callosum, midbrain, and posterior cortex. Neuropsychologia. 2005;43(14):2000-10.

Horizontal and vertical line bisection was studied in 129 children and adolescents between 8 and 19 years of age, one group (n=32) of typically developing controls and one group (n=97) with spina bifida (SBM), a neurodevelopmental disorder associated with dysmorphology of the corpus callosum, posterior cortex, and midbrain. For each participant, structural brain MRIs were analyzed qualitatively to identify beaking of the midbrain tectum and corpus callosum agenesis and hypoplasia and quantitatively by segmentation and volumetric analyses of regional cortical white and gray matter. Each group showed the line length effect, whereby greater estimation errors are made with longer lines. The group with SBM differed from controls in terms of both accuracy and variability of line bisection. Children with SBM showed pseudoneglect, attending more than controls to left hemispace. The extent of rightward bisection bias was unrelated to right posterior brain volumes, although an intact corpus callosum during development moderated and normalized the exaggerated leftward line bisection bias. More children with SBM than controls attended to inferior hemispace. A normal midbrain and greater posterior cortex volume during development moderated and normalized the downward bias. Children with SBM showed more intra-subject variability than controls. Line bisection in children with SBM reflects three deficits: an exaggerated attentional bias to left hemispace, an abnormal attentional bias to inferior hemispace; and a larger zone of subjective uncertainty in bisection judgments.

PMID: 15893777

Idiom comprehension deficits in relation to corpus callosum agenesis and hypoplasia in children with spina bifida meningomyelocele.

Huber-Okrainec J, Blaser SE, Dennis M. Idiom comprehension deficits in relation to corpus callosum agenesis and hypoplasia in children with spina bifida meningomyelocele. Brain & Language. 2005 Jun;93(3):349-68. Epub 2005 Jan 28.

Idioms are phrases with figurative meanings that are not directly derived from the literal meanings of the words in the phrase. Idiom comprehension varies with: literality, whether the idiom is literally plausible; compositionality, whether individual words contribute to a figurative meaning; and contextual bias. We studied idiom comprehension in children with spina bifida meningomyelocele (SBM), a neurodevelopmental disorder associated with problems in discourse comprehension and agenesis and hypoplasia of the corpus callosum. Compared to age peers, children with SBM understood decomposable idioms (which are processed more like literal language) but not non-decomposable idioms (which require contextual analyses for acquisition). The impairment in non-decomposable idioms was related to congenital agenesis of the corpus callosum, which suggests that the consequences of impaired interhemispheric communication, whether congenital or acquired in adulthood, are borne more by configurational than by compositional language.

PMID: 15862859

Thursday, July 26, 2007

Arnold-Chiari-II malformation and cognitive functioning in spina bifida

Vinck A, Maassen B, Mullaart R, Rotteveel J. Arnold-Chiari-II malformation and cognitive functioning in spina bifida. Journal of Neurology, Neurosurgery & Psychiatry. 2006 Sep;77(9):1083-6. Epub 2006 May 11.

Spina bifida is a multifaceted neurological condition with complex neuropsychological sequelae. The cognitive outcome in spina bifida has frequently been attributed to the severity of the hydrocephalus. However, because of complex neuropathology, the influence of hydrocephalus alone does not sufficiently explain the deficits in the cognitive profile in spina bifida. To date, little is known of the role of Arnold-Chiari-II malformation (ACM) in the cognitive profile of these patients. Aim of the current study is to delineate the specific contribution of the ACM in spina bifida by comparing children with ACM and those without ACM. 46 children between 6 and 15 years of age underwent a neuropsychological assessment covering intelligence and a wide range of cognitive functions, such as visuo-motor processing, attention, memory, word fluency and speed of information processing. Comparisons were made between patients with ACM (ACM+) and those without ACM (ACM-); all children with ACM+ also had hydrocephalus. Confounding effects of global cognitive impairment were excluded, such that groups were matched on verbal IQ. Because of complex neuropathology, which is inherent to spina bifida, the method applied was based on a comparison of cognitive profiles of the study group with profiles of patients with cerebellar damage and hydrocephalus found in the literature. Impaired visual analysis and synthesis, verbal memory, and verbal fluency, even after correction for global cognitive impairment, were observed in children with ACM. The hypothesis that in addition to impairment in visual analysis and synthesis, which are related to both hydrocephalus and ACM, specific deficiencies in verbal memory and fluency may be attributed to ACM is supported.

PMID: 16690692

Hand function in subjects with spina bifida

Muen WJ, Bannister CM. Hand function in subjects with spina bifida.
European Journal of Pediatric Surgery. 1997 Dec;7 Suppl 1:18-22.

The aim of our study was to assess the influence of the Arnold-Chiari malformation, cervical cord dysraphism and hydrocephalus on hand function in subjects with meningomyelocele, but without many of the other confounding factors commonly found in this group e.g low IQ and cerebral palsy, which in themselves cause poor hand function. Three groups of subjects who attended main stream schools underwent a basic neurological examination of the upper limbs and a battery of hand function tests. Group 1 consisted of subjects with meningomyelocele and shunted hydrocephalus (n = 21), Group 2 subjects had isolated shunted hydrocephalus (n = 13) and Group 3 were normal controls (n = 18). The results show that subjects with meningomyelocele had weaker power in the small muscles of the hand as compared to the controls and those with isolated hydrocephalus (p = 0.01) and poorer fine motor control and co-ordination. The meningomyelocele group scored significantly poorer in all of the tests as compared to the control group using the dominant hand (overall, p = 0.0003), and all of the tests but one using the non-dominant hand (overall, p = 0.0005). Our study has demonstrated that children with meningomyelocele have poorer hand function than healthy controls, which is due to causes other than hydrocephalus, poor IQ or cerebral hemisphere pathology. Instead, cerebellar and cervical cord abnormalities appear to be exerting a significant deleterious influence on the function of the upper limbs.

PMID: 9497111

Craniofacial asymmetries in shunt-treated hydrocephalic children

Pirttiniemi PM, Huggare JA, Kantomaa TJ, Serlo WS. Craniofacial asymmetries in shunt-treated hydrocephalic children. The Cleft Palate-Craniofacial Journal. 1991 Oct;28(4):369-72.

The degree and direction of craniofacial asymmetry in the frontal plane was studied in a sample of 26 shunt-treated hydrocephalic children aged 5 to 18 years. Thirteen of the children had the regulating shunt fixed on the right side of the head and 13 on the left. The shunt had usually been inserted during the first years of life. An age- and sex-matched group of healthy school children and students served as controls for cephalometric assessment by means of linear and angular measurements. Considerable craniofacial asymmetry was found in the shunt-treated hydrocephalic children, the direction of asymmetry being related to the laterality of the regulating shunt device. The most marked asymmetric changes were recorded in the maxillary and mandibular regions, probably due to the adaptive nature of these regions.

PMID: 1742305

Dental maturation in children with shunt-treated hydrocephalus

Pirttiniemi P, Poikela A, Huggare J, Lopponen T. Dental maturation in children with shunt-treated hydrocephalus. The Cleft Palate-Craniofacial Journal. 2004 Nov;41(6):651-4.

OBJECTIVE: The aim of this study was to examine the relationship between dental maturation and somatic development and to discover their possible deviations in children with shunt-treated hydrocephalus.

DESIGN: Radiographs (orthopantomogram and hand-wrist radiograph) from children with shunt-treated hydrocephalus were analyzed with respect to the dental maturation and compared with values of an age- and sex-matched control group and population standards.

PATIENTS: Forty-one children with shunt-treated hydrocephalus (27 boys and 14 girls) aged from 5 to 16 years (median age 11.0 years).

RESULTS: The mean deviation of dental age from chronological age was significantly greater in the hydrocephalic group than in the control group. The mean value of dental age deviation was advanced in early pubertal stages but reduced in later pubertal stages.

CONCLUSIONS: These findings can be explained by changes in the endocrinological conditions, which are due to disturbed pituitary secretion. The present results could also partly reflect an adaptable developmental pathway in an otherwise strictly genetically determined process.

PMID: 15516170
Full Text Online

Pituitary function in children with hydrocephalus before and after the first shunting operation

Lopponen T, Saukkonen AL, Serlo W, Tapanainen P, Ruokonen A, Lanning P, Knip M. Pituitary function in children with hydrocephalus before and after the first shunting operation. European Journal of Endocrinology. 1998 Feb;138(2):170-5.

OBJECTIVE: Children with shunted hydrocephalus experience slow linear growth in prepuberty, accelerated pubertal maturation and a reduced final height. A substantial proportion of these patients have a poor growth hormone (GH) response to stimulation and reduced pituitary volume. The basic mechanisms behind these phenomena are still unknown, but one can hypothesize that an unphysiological intracranial pressure (ICP) may be involved. This study was undertaken to investigate the effect of increased ICP on pituitary function.

DESIGN: Twenty-one children (nine males) aged 4 months to 15 years were evaluated for pituitary function before and after their first shunting operation.

METHODS: A clinical examination was performed, bone age was determined and a combined pituitary stimulation test was performed to evaluate GH, luteinizing hormone, follicle-stimulating hormone, cortisol, thyrotropin and prolactin secretion.

RESULTS: GH concentrations were significantly higher 10 and 15 min before the operation (P=0.04 and P=0.03 respectively) than after it. The basal levels of insulin-like growth factor-I (IGF-I) tended to be higher before the operation than afterwards and those of its binding protein-3 (IGFBP-3) were significantly so (P<0.01).

CONCLUSIONS: The higher GH response to GH releasing hormone and circulating IGFBP-3 levels in children with hydrocephalus before compared with after their first shunting operation raise the possibility that the reduced GH secretion and retarded linear growth observed in children with shunted hydrocephalus may be a consequence of decreased ICP and/or the lack of physiological pressure variations.

PMID: 9506861
Full Text Online

Reduced levels of growth hormone, insulin-like growth factor-I and binding protein-3 in patients with shunted hydrocephalus.

Lopponen T, Saukkonen AL, Serlo W, Tapanainen P, Ruokonen A, Knip M. Reduced levels of growth hormone, insulin-like growth factor-I and binding protein-3 in patients with shunted hydrocephalus. Archives of Disease in Childhood. 1997 Jul;77(1):32-7.

OBJECTIVE: Children with hydrocephalus are characterised by slow linear growth in prepuberty, accelerated physical maturation during puberty, and reduced final height. We aimed to study the possible roles of growth hormone, insulin-like growth factor-I (IGF-I), and IGF binding protein-3 (IGFBP-3) in this growth pattern. STUDY

DESIGN: One hundred and fourteen patients with shunted hydrocephalus (62 males) aged 5 to 20 years, of whom 17 had spina bifida (six males), and 73 healthy controls (38 males) were studied. Anthropometric measures, body mass index, and body fat mass were assessed and the stage of puberty was determined. Serum growth hormone and plasma IGF-I and IGFBP-3 concentrations were measured.

RESULTS: The patients comprised 44 (26 males) who were prepubertal and 70 (36 males) pubertal or postpubertal, while 32 of the controls (19 males) were prepubertal and 41 (19 males) pubertal or postpubertal. The prepubertal children with hydrocephalus had lower IGF-I (p = 0.002) and IGFBP-3 concentrations (p < 0.001) than the controls, and the pubertal children had four times lower basal growth hormone concentrations (p < 0.001). There was a correlation between height SD score and IGF-I levels in the total patient population (r = 0.23; p = 0.01). Peripheral IGF-I concentrations peaked at pubertal stages 2-3 in the female patients and at stage 4 in the controls. The prepubertal patients on antiepileptic treatment, carbamazepine in most cases (73%), had higher IGF-I (p = 0.01) and IGFBP-3 concentrations (p = 0.03) than those who had never been treated with antiepileptic drugs, but still lower IGFBP-3 levels than the controls (p = 0.01).

CONCLUSION: Based on these findings, it can be concluded that reduced growth hormone secretion may contribute to the pattern of slow linear growth and reduced final height observed in these patients.

PMID: 9279148
Full Text Online

Wednesday, July 25, 2007

Spinal fusion in children with spina bifida: influence on ambulation level and functional abilities

Schoenmakers MA, Gulmans VA, Gooskens RH, Pruijs JE, Helders PJ. Spinal fusion in children with spina bifida: influence on ambulation level and functional abilities. European Spine Journal. 2005 May;14(4):415-22. Epub 2004 Jul 16.

The aim of this study was to determine the influence of spinal fusion on ambulation and functional abilities in children with spina bifida for whom early mobilization was stimulated. Ten children (three males and seven females) with myelomeningocele were prospectively followed. Their mean age at operation was 9.3 years (standard deviation (SD): 2.4). Spinal curvature was measured according to Cobb. Pelvic obliquity and trunk decompensation were measured as well. The ambulation level was scored according to Hoffer, and functional abilities, as well as the amount of caregiver assistance, were documented using the Pediatric Evaluation of Disability Inventory. All patients were assessed before surgery and three times after surgery, with a total follow-up duration of 18 months after surgery. After spinal fusion, magnitude of primary curvature decreased significantly (p=0.002). Pelvic obliquity and trunk decompensation did not change. In spite of less immobilization as compared with other reported experiences, ambulation became difficult in three out of four patients who had been able to ambulate prior to surgery. Functional abilities and amount of caregiver assistance concerning self-care (especially regarding dressing upper and lower body, and self-catheterization) and mobility (especially regarding transfers) showed a nonsignificant trend to deterioration within the first 6 months after surgery, but recovered afterwards. From pre-surgery to 18 months after surgery, functional skills on self-care showed borderline improvement (p=0.07), whereas mobility did not (p=0.2). Mean scores on caregiver assistance improved significantly on self-care (p=0.03), and borderline on mobility (p=0.06), meaning that less caregiver assistance was needed compared with pre-surgery. The complication rate was high (80%). In conclusion, within the first 6 months after spinal fusion, more caregiver assistance is needed in self-care and mobility. It takes about 12 months to recover to pre-surgery level, while small improvement is seen afterwards. After spinal fusion, ambulation often becomes difficult, especially in exercise walkers. These findings are important for health-care professionals, in order to inform and prepare the patients and their parents properly for a planned spinal fusion.

PMID: 15258836

Syringomyelia complicating myelomeningocele: review of the evidence

Piatt JH Jr. Syringomyelia complicating myelomeningocele: review of the evidence. Journal of Neurosurgery. 2004 Feb;100(2 Suppl Pediatrics):101-9. Review.

Syringomyelia is frequently found in association with myelomeningocele. Although often asymptomatic, it can, in exceptional cases, cause severe morbidity. The author performed a structured literature review to address the following aspects of this clinical problem. What is the natural history? There are data concerning the imaging prevalence, the autopsy prevalence, and the prevalence of clinically active syringomyelia among patients with myelomeningocele, but literature provides no description of the course of this condition over time. What is the clinical significance? That correlations among symptoms, signs, treatments, and imaging findings are poorly described is no surprise in view of the large fraction of patients with syringomyelia who are asymptomatic. There is, however, an impressive mass of anecdotal evidence associating progressive syringomyelia with untreated (or inadequately treated) hydrocephalus. How to make the diagnosis? There is no disagreement that magnetic resonance imaging is the diagnostic modality of choice, but the literature provides very little guidance about who should undergo this investigation. There is no analysis of the costs and benefits of screening or periodic surveillance. What is the best treatment? Many surgical procedures have been reported to be useful as components of complex algorithms relating clinical factors and imaging data to treatment recommendations. There have been no controlled studies. There have been no prospective studies. There have been no multiinstitutional studies. No studies in which outcomes have been evaluated using objective, validated instruments. No studies in which the robustness of treatment effects over time have been documented. The complexity of treatment selection in contemporary practice makes syringomyelia unsuitable for randomized controlled trials of different therapies. Prospective cohort studies are feasible, however, and hold the potential to address many important questions about natural history and patient outcomes.

PMID: 14758937

In-hospital mortality rates after ventriculoperitoneal shunt procedures in the United States, 1998 to 2000: relation to hospital and surgeon volume of

Smith ER, Butler WE, Barker FG 2nd. In-hospital mortality rates after ventriculoperitoneal shunt procedures in the United States, 1998 to 2000: relation to hospital and surgeon volume of care. Journal of Neurosurgery. 2004 Feb;100(2 Suppl Pediatrics):90-7.

OBJECT: Death after ventriculoperitoneal (VP) shunt surgery is uncommon, and therefore it has been difficult to study. The authors used a population-based national hospital discharge database to examine the relationship between annual hospital and surgeon volume of VP shunt surgery in pediatric patients and in-hospital mortality rates.

METHODS: All children in the Nationwide Inpatient Sample (1998-2000, age 90 days-18 years) who underwent VP shunt placement or shunt revision as the principal procedure were included. Main outcome measures were in-hospital mortality rates, length of stay (LOS), and total hospital charges. Overall, 5955 admissions were analyzed (253 hospitals, 411 surgeons). Mortality rates were lower at high-volume centers and for high-volume surgeons. In terms of hospital volume, the mortality rate was 0.8% at lowest-quartile-volume centers (< 28 admissions/year) and 0.3% at highest-quartile-volume centers (> 121 admissions/year). In terms of surgeon volume, the mortality rate was 0.8% for lowest-quartile-volume providers (< nine admissions/year) and 0.1% for highest-quartile-volume providers (> 65 admissions/year). After multivariate adjustment for demographic variables, emergency admission and presence of infection, hospital volume of care remained a significant predictor of death (odds ratio [OR] for a 10-fold increase in caseload 0.38; 95% confidence interval [CI] 0.18-0.81). Surgeon volume of care was statistically significant in a similar multivariate model (OR for a 10-fold increase in caseload 0.3; 95% CI 0.13-0.69). Length of stay was slightly shorter and total hospital charges were slightly higher at higher-volume centers, but the differences were not statistically significant.

CONCLUSIONS: Pediatric shunt procedures performed at high-volume hospitals or by high-volume surgeons were associated with lower in-hospital mortality rates, with no significant difference in LOS or hospital charges.

PMID: 14758935

Taxonicity of nonverbal learning disabilities in spina bifida.

Ris MD, Ammerman RT, Waller N, Walz N, Oppenheimer S, Brown TM, Enrile BG, Yeates KO. Taxonicity of nonverbal learning disabilities in spina bifida. Journal of the International Neuropsychological Society. 2007 Jan;13(1):50-8.

As currently defined, it is not clear whether Nonverbal Learning Disabilities (NLD) should be considered a matter of kind or magnitude (Meehl, 1995). The taxonicity of NLD, or the degree to which it is best construed as discrete versus continuous, has not been investigated using methods devised for this purpose. Latent Class Analysis (LCA) is a method for finding subtypes of latent classes from multivariate categorical data. This study represents an application of LCA on a sample of children and adolescents with spina bifida myelomeningocele (SBM) (N = 44), those presenting with features of NLD (N = 28) but no medical condition, and control volunteers (N = 44). The two-class solution provided evidence for the presence of a taxon with an estimated base-rate in the SBM group of .57. Indicator validities (the conditional probabilities of indicator endorsement in each latent class) suggest a somewhat different priority for defining NLD than is typically used by researchers investigating this disorder. A high degree of correspondence between LCA classifications and those based on a more conventional algorithm provided evidence for the validity of this approach.

PMID: 17166303

Language differences in young children with myelomeningocele and shunted hydrocephalus

Vachha B, Adams R. Language differences in young children with myelomeningocele and shunted hydrocephalus. Pediatric Neurosurgery. 2003 Oct;39(4):184-9.

OBJECTIVE: This comparative cohort study examined language differences in young children (preschool to first grade) with myelomeningocele and shunted hydrocephalus (MM/SH).

METHOD: A well-validated, standardized language test was administered to 17 children with MM/SH (age range 4-6 years) and 16 age-matched, nonaffected children.

RESULTS: Standard scores were obtained within lexical/semantic, syntactic, and pragmatic domains. An analysis of performance on individual subtests within the lexical/semantic domain was striking. Children with MM/SH performed significantly worse (p<0.01) on a test measuring the comprehension of words representing important early learning concepts and on pragmatic tasks that measured their ability to use language functionally in social situations.

CONCLUSIONS: Words representing basic precepts and concepts are commonly used in instructions to children in early childhood. Difficulty with functional pragmatic language results in suboptimal communication skills. Academic and community implications are discussed.

PMID: 12944698

Do children with myelomeningocele and hydrocephalus display nonverbal learning disabilities?

Yeates KO, Loss N, Colvin AN, Enrile BG. Do children with myelomeningocele and hydrocephalus display nonverbal learning disabilities? An empirical approach to classification. Journal of the International Neuropsychological Society. 2003 May;9(4):653-62.

As a group, children with myelomeningocele (MM) and early-onset hydrocephalus demonstrate many of the features of the syndrome of nonverbal learning disabilities (NLD). However, the frequency with which individual children display a pattern of neuropsychological functioning consistent with the NLD syndrome is unknown. We addressed this question by comparing the prevalence of NLD in 32 children with MM and shunted hydrocephalus to that in a group of 27 healthy siblings. Participants, who were between 8 and 15 years of age, completed a neuropsychological test battery that included 11 measures of possible assets and 17 measures of possible deficits that define the NLD syndrome. As a group, children with MM and shunted hydrocephalus displayed many of the specific assets and deficits. However, they also displayed significantly more variability in their patterns of assets and deficits than siblings, reflecting the substantial individual differences that characterize children with MM. About 50% of the children with myelomeningocele displayed a pattern of assets and deficits consistent with the NLD syndrome. Classification as NLD was weakly related to cumulative medical risk, as well as to left-handedness. The findings suggest a need for caution in making generalizations regarding the applicability of the NLD model to children with MM and early-onset hydrocephalus.

PMID: 12755177

Tuesday, July 24, 2007

Transient ventriculoperitoneal shunt dysfunction in children with myelodysplasia and urinary bladder infection. Report of three cases.

Tubbs RS, Wellons JC 3rd, Blount JP, Oakes WJ. Transient ventriculoperitoneal shunt dysfunction in children with myelodysplasia and urinary bladder infection. Report of three cases. Journal of Neurosurgery. 2005 Mar;102(2 Suppl):221-3.

The authors present three children born with myelomeningocele and hydrocephalus. Each presented with symptoms/signs of ventriculoperitoneal shunt malfunction. All patients at the time of presentation exhibited significant urinary bladder infections and were appropriately treated for their infection. No patient was found to have an underlying shunt infection. All patients without medically threatening symptoms were carefully observed and noted to have resolution of their shunt dysfunction symptoms/signs following treatment of their urinary bladder infections and thus did not undergo a shunt operation. Based on the courses of these patients, we believe that significant urinary bladder infection in patients with myelodysplasia in whom a shunt has been placed may often be enough to bring a subclinical shunt malfunction to clinical attention or even to be the cause of temporary distal peritoneal shunt malabsorption. Although the exact mechanism for this dysfunction is unclear, treatment of the bladder infection may address the symptomatic shunt dysfunction in some patients so as to avoid operative intervention. We emphasize, however, that careful observation of these patients should be performed during hospitalization because they often rely on adequate cerebrospinal fluid diversion. Only patients with mild symptomatology should be observed first as the initial line of treatment.

PMID: 16156234

Referred shoulder pain from ventriculoperitoneal shunts. Report of three cases.

Tubbs RS, Wellons JC 3rd, Blount JP, Grabb PA, Oakes WJ. Referred shoulder pain from ventriculoperitoneal shunts. Report of three cases. Journal of Neurosurgery. 2005 Mar;102(2 Suppl):218-20.

The authors report on three pediatric patients with ventriculoperitoneal (VP) shunts who presented with chronic right shoulder pain. Imaging revealed that the distal peritoneal catheter was positioned between the right hemidiaphragm and liver. Following surgical repositioning of the distal tubing, all patients experienced resolution of their shoulder pain, which has not recurred. Although seemingly rare, referred shoulder pain from a VP shunt should be added to the list of complications seen with this method of cerebrospinal fluid diversion. The clinician who cares for patients with VP shunts may wish to evaluate cases of shoulder pain without obvious neural or musculoskeletal cause by performing imaging of the distal shunt tubing.

PMID: 16156233

Adult tethered cord syndrome in patients with postrepair myelomeningocele: an evidence-based outcome study

George TM, Fagan LH. Adult tethered cord syndrome in patients with postrepair myelomeningocele: an evidence-based outcome study. Journal of Neurosurgery. 2005 Mar;102(2 Suppl):150-6. Review.

OBJECT: As patients with myelomeningocele age, tethered cord syndrome (TCS) in adults with postrepair myelomeningocele has become more common. The authors have structured an evidence-based review of the literature for the purpose of addressing the following questions. (1) How is the diagnosis made? (2) What is the natural history that occurs in adults with postrepair myelomeningocele and TCS? (3) What are the criteria for operative intervention? (4) What is the functional outcome for patients with postrepair myelomeningocele?

METHODS: A computerized search of the National Library of Medicine of the English-language literature published from 1966 to 2003 was performed. Articles pertaining to the clinical aspects and management of postrepair myelomeningocele in adults, TCS in adults resulting from closed defects, and pediatric patients with postrepair myelomeningocele were reviewed. No Level 1 or 2 data were located; however, the search yielded Level 3 and 4 evidence in the literature in which the clinical syndrome, underlying pathology, and the imaging and electrophysiological evaluation for TCS in adults are discussed.

CONCLUSIONS: Analysis of the available data indicates the following. (1) A lower lesion level predisposes patients to symptomatic tethering; moreover, orthopedic and urological deterioration will occur in the majority of these patients. (2) Tethered cord release should be considered for adult patients with postrepair myelomeningocele when clinical symptoms, imaging studies, urodynamics, and somatosensory evoked potentials are consistent with TCS. (3) Prompt, aggressive untethering surgery within 5 years of symptom onset, along with long-term follow up to check for delayed retethering, is recommended. The overall outcome for patients with postrepair myelomeningocele may not be as good as the outcome for adults with closed dysraphism.

PMID: 16156223

Periventricular rigidity in long-term shunt-treated hydrocephalus.

Sood S, Lokuketagoda J, Ham SD. Periventricular rigidity in long-term shunt-treated hydrocephalus. Journal of Neurosurgery. 2005 Mar;102(2 Suppl):146-9.

OBJECT: The failure of ventricles to enlarge after acute shunt malfunction in long-term shunt-dependent patients is generally attributed to the presence of periventricular rigidity resulting from gliosis. The aim of this study was to test the hypothesis that periventricular rigidity is present in these patients.

METHODS: Fifteen pediatric patients who presented with acute shunt malfunction were studied; slit ventricles were detected in all of these patients. Pressure measurements were recorded simultaneously in both the ventricle and the brain parenchyma during shunt revision and then repeated after bolus infusion of fluid into the ventricle. The mean intraventricular pressure (IVP) at presentation was 24.1 mm Hg (standard deviation 10 mm Hg). The mean baseline IVP after drainage of cerebrospinal fluid but prior to the infusion was 7.5 +/- 4.3 mm Hg. There was no significant difference in the increase in the IVP and the intraparenchymal pressure (IPP) after bolus infusion into the ventricle (3.6 +/- 2.4 mm Hg and 3.3 +/- 2.1 mm Hg, respectively; p = 0.39). The mean pressure volume index was 24.1 ml (standard error of the mean 4.6 ml).

CONCLUSIONS: The profile of the changes in IVP and IPP indicates that the periventricular wall does not restrict ventricular enlargement following shunt malfunction in long-term shunt-dependent patients.

PMID: 16156222

Neurosurgical causes of scoliosis in patients with myelomeningocele: an evidence-based literature review

Dias MS. Neurosurgical causes of scoliosis in patients with myelomeningocele: an evidence-based literature review. Journal of Neurosurgery. 2005 Jul;103(1 Suppl):24-35. Review.

OBJECT: Scoliosis in children with myelomeningocele occurs frequently and is multifactorial in origin. The aim of this paper is to review the evidence regarding the causal association, if any, between isolated scoliosis and spinal cord tethering, Chiari malformation, or syringomyelia in this population.

METHODS: A Medline search of the English-language literature from 1966 to 2002 was undertaken. All of the pertinent articles that were identified underwent careful review to determine the strength of the evidence supporting the claim that isolated scoliosis in children with myelomeningocele is related to spinal cord tethering, Chiari malformation, or syringomyelia. The strength of the evidence was graded using the Oxford Centre for Evidence-Based Medicine Levels of Evidence (May 2001). A survey was also sent to practicing pediatric neurosurgeons and the returned responses were evaluated.

CONCLUSIONS: All available studies were classified as Level 4 studies (case series and flawed cohort and case-control studies). Based on the strength of the available data, there may be an association between spinal cord tethering and scoliosis, particularly in those patients with upper lumbar lesions and spinal curves less than 45 degrees. There is little evidence to support a causal relationship between scoliosis and Chiari malformation or syringomyelia in this population.

PMID: 16122001

Long-term outcome of hydrocephalus management in myelomeningoceles.

Tuli S, Drake J, Lamberti-Pasculli M. Long-term outcome of hydrocephalus management in myelomeningoceles. Child's Nervous System. 2003 Jun;19(5-6):286-91. Epub 2003 May 23.

BACKGROUND: The cerebrospinal fluid (CSF) shunt remains an important ongoing management problem in myelomeningocele (MMC) patients. We reviewed the long-term shunt treatment outcome in a prospectively followed group of MMC patients from a single institution.

METHOD: Patients prospectively entered into a hydrocephalus database with a diagnosis of MMC from the years 1987 to 1996 were selected. All data was verified from the medical records and additional details about the shunt surgery were collected. The outcome of shunt failure was categorized as shunt obstruction, shunt infection, presence of loculated ventricles, overdrainage, and other. All deaths were recorded and causation identified. Univariate analysis for shunt failure risk factors was accomplished using Log rank statistics. Multivariable analysis was performed for each repeated failure level using a conditional Cox regression model.

RESULTS: One hundred and twenty (64%) out of 189 MMC patients experienced a first shunt failure with a median time of 303 days; 29 (24%) of the failures were due to shunt infection (the procedure infection rate being 15%). Sixty-one patients experienced a second shunt failure, 38 a third and 36 had four or more. Multivariable analysis of risk factors failed to demonstrate any clear risk factors for either first or subsequent shunt failure. Fifteen patients died, 13 from either shunt or Chiari 1 complications.

CONCLUSION: Shunt complications remain an important cause of morbidity and mortality in MMC patients, particularly shunt infection.

PMID: 12764629

Death in shunted hydrocephalic children in the 1990s.

Iskandar BJ, Tubbs S, Mapstone TB, Grabb PA, Bartolucci AA, Oakes WJ. Death in shunted hydrocephalic children in the 1990s. Pediatric Neurosurgery. 1998 Apr;28(4):173-6.

Using a combined search of the Children's Hospital (Birmingham, Ala., USA) medical records and the Jefferson County Health Department death records, we reviewed all shunt-related deaths that occurred between January 1990 and July 1996. Of these, we excluded patients who died of nonhydrocephalus-related reasons, such as bronchopulmonary dysplasia, as well as patients who had other serious neurological illnesses such as brain tumor and hydranencephaly. Twenty-eight patients died of shunt-related causes in the 6.5-year period. A survival analysis showed that 96% survived 32 months after first shunting. Of 28 patients, 23 were beyond help prior to medical evaluation. However, at least 10 of these patients had symptoms suggestive of shunt failure at least 24 h and as long as 2 weeks prior to their demise. We conclude that hydrocephalic children still die of shunt failure despite the modern technology of the 1990s. Some of these causes may be avoidable through early detection of symptoms. Guidelines to patients, families, and primary caregivers should be emphasized.

PMID: 9732242

Death in shunted hydrocephalic children: a follow-up study.

Acakpo-Satchivi L, Shannon CN, Tubbs RS, Wellons JC 3rd, Blount JP, Iskandar BJ, Oakes WJ. Death in shunted hydrocephalic children: a follow-up study. Child's Nervous System. 2007 Jun 27;

INTRODUCTION: The authors previously conducted a retrospective study regarding deaths from CSF shunt failure to identify circumstances surrounding shunt malfunction-related deaths in children in the modern era.

MATERIALS AND METHODS: Using the same methodology, we conducted a follow-up study to determine whether recent policy and procedural changes instituted since the time of the first study had effected a change in the mortality rate of our shunted patient population. RESULTS: Thirty-nine original patient records (of patients seen at Children's Hospital who died with the diagnosis of hydrocephalus between 1998 and 2004) were identified and reviewed for inclusion into the study. Only four (10.3%) were found to have died directly as a result of shunt malfunction.

CONCLUSIONS: Our rate of shunt malfunction death has decreased over time. It is reasonable to attribute part of this decline to continued improvements in diagnostic and therapeutic techniques and to the use of surveillance scans to identify asymptomatic patients with shunt failure. However, we believe the majority of this decline is due to two additional factors: (1) increased nursing staff and (2) effective patient/family education.

PMID: 17594102

Time trends and demographics of deaths from congenital hydrocephalus in children in the United States: 1979 to 1998

Chi JH, Fullerton HJ, Gupta N. Time trends and demographics of deaths from congenital hydrocephalus in children in the United States: National Center for Health Statistics data, 1979 to 1998. Journal of Neurosurgery. 2005 Aug;103(2 Suppl):113-8.

OBJECT: Congenital hydrocephalus has an estimated population incidence of 0.2 to 0.8/1000 live births. With improvements in techniques for cerebrospinal fluid shunting, treatment of hydrocephalus has become safe and routine, yet data describing mortality from congenital hydrocephalus or demonstrating improvements in mortality with the advent of modern treatment are scarce. The authors' analysis sought to rectify this situation.

METHODS: The authors performed an electronic search of National Center for Health Statistics death certificate databases to identify deaths from 1979 to 1998 attributed to congenital hydrocephalus, spina bifida with hydrocephalus, and acquired hydrocephalus (both obstructive and communicating) in all children in the US aged 1 day to 20 years. Mortality rates were defined as deaths per 100,000 person-years and were analyzed for differences on the basis of age, race, sex, and year. The authors identified 10,406 deaths attributed to childhood hydrocephalus within the 20-year study period. The overall mortality rate was 0.71 per 100,00 person-years. Mortality rates were highest in infants, with 3979 deaths; they were similar between girls and boys. Compared with white infants, black infants had higher relative risk (RR) for death caused by congenital hydrocephalus (RR 1.46, p value < 0.0001) and acquired hydrocephalus (RR 2.58, p value < 0.0001) but not for that caused by hydrocephalus with spina bifida (RR 0.65, p value < 0.0001). From 1979 to 1998, the mortality rate due to congenital hydrocephalus declined 66.3%, from spina bifida with hydrocephalus it declined by 30.4%, and from acquired hydrocephalus it declined by 67.5%.

CONCLUSIONS: Mortality rates from childhood hydrocephalus have declined in US children over the previous 20 years. Black race is associated with higher mortality rates in infants for both congenital and acquired hydrocephalus, whereas sex has no effect.

PMID: 16370275

Tissue expansion for the delayed closure of large myelomeningoceles.

Mowatt DJ, Thomson DN, Dunaway DJ. Tissue expansion for the delayed closure of large myelomeningoceles. Journal of Neurosurgery. 2005 Dec;103(6 Suppl):544-8.

OBJECT: Numerous techniques for the soft-tissue closure of large myelomeningoceles have been described. When patients present for delayed repair beyond the neonatal period, the indications for surgery are both different and less immediate.

METHODS: Six patients between 6 weeks and 3.5 years of age with defects ranging from 27 to 49 cm2 (mean 37 cm2) were referred to the authors' institution and were successfully treated by direct skin closure after tissue expansion.

CONCLUSIONS: In this paper the authors describe the technique and advantages of expansion compared with those of locoregional flaps in this subgroup of patients with myelomeningoceles.

PMID: 16383254

Early programmable valve malfunctions in pediatric hydrocephalus.

Mangano FT, Menendez JA, Habrock T, Narayan P, Leonard JR, Park TS, Smyth MD. Early programmable valve malfunctions in pediatric hydrocephalus. Journal of Neurosurgery. 2005 Dec;103(6 Suppl):501-7.

OBJECT: The use of adjustable differential pressure valves has been recommended to improve ventriculoperitoneal (VP) shunt performance in selected patients; however, published data are scarce regarding their clinical reliability. Recently, the identification of a number of malfunctioning programmable valves during shunt revision surgery in children prompted a retrospective review of valve performance in this patient cohort.

METHODS: The authors performed a retrospective chart analysis of 100 patients with programmable valve shunts and 89 patients with nonprogrammable valve shunts implanted at the St. Louis Children's Hospital between April 2002 and June 2004. They noted the cause of hydrocephalus, the type of shunt malfunction, and cerebrospinal fluid (CSF) protein levels. Regular clinical follow up ranged from 1 to 26 months, with a mean follow-up time of 9.75 months for patients with programmable valves and 10.4 months for patients with nonprogrammable valves. Patient ages ranged from 2 weeks to 18 years. One hundred patients had 117 programmable valves implanted, and 35 of these patients (35%) underwent shunt revision because of malfunction. The programmable valve itself malfunctioned in nine patients who had undergone shunt revision (11.1%/year of follow up). The nonprogrammable valve group had no valve malfunctions. The overall VP shunt revision rate in the nonprogrammable valve group was 20.2%. No significant differences were identified when CSF protein levels and specific malfunction types were compared within the programmable valve and nonprogrammable valve groups.

CONCLUSIONS: In this study the authors demonstrated an annualized intrinsic programmable valve malfunction rate of 11.1%, whereas during the same period no intrinsic valve malfunctions were noted with nonprogrammable valve systems for similar causes of hydrocephalus. The CSF protein levels did not correlate with observed valve malfunction rates. Further evaluation in a prospective, randomized fashion will elucidate specific indications for programmable valve systems and better determine the reliability of these valves in the pediatric population.

PMID: 16383248

Effect of an intraoperative double-gloving strategy on the incidence of cerebrospinal fluid shunt infection.

Tulipan N, Cleves MA. Effect of an intraoperative double-gloving strategy on the incidence of cerebrospinal fluid shunt infection. Journal of Neurosurgery. 2006 Jan;104(1 Suppl):5-8.

OBJECT: The purpose of this study was to determine the effect of double gloving on cerebrospinal fluid (CSF) shunt infection rates.

METHODS: Data obtained in two large groups of patients, one in which the surgical personnel wore a single pair of gloves each and the other in which the personnel wore two pairs of gloves each, were retrospectively studied. The study involved 863 patients. The overall infection rate in the single-gloved group was 15.2%, whereas it was 6.7% in the double-gloved group (p = 0.0002). Of additional interest was the marked difference between the overall shunt infection rates in younger children (< 11.3 years of age; 15.7%) and older children (> 11.3 years of age) and adults (6.7%; p < 0.00005).

CONCLUSIONS: The strategy of wearing two pairs of gloves while performing surgery appears to reduce the incidence of postoperative shunt infection by more than 50%. The incidence of shunt infection is highly age dependent. The shunt infection rate may be further reduced by carefully studying the individual variables associated with the shunt insertion procedure.

PMID: 16509473

What we don't (but should) know about hydrocephalus.

Bergsneider M, Egnor MR, Johnston M, Kranz D, Madsen JR, McAllister JP, Stewart C, Walker ML, Williams MA. What we don't (but should) know about hydrocephalus.
Journal of Neurosurgery. 2006 Mar;104(3 Suppl):157-9.

In an effort to identify critical gaps in the prevailing knowledge of hydrocephalus, the authors formulated 10 key questions. 1) How do we define hydrocephalus? 2) How is cerebrosinal fluid (CSF) absorbed normally and what are the causes of CSF malabsorption in hydrocephalus? 3) Why do the ventricles dilate in communicating hydrocephalus? 4) What happens to the structure and function of the brain when it is compressed and stretched by the expanding ventricles? 5) What is the role of cerebrovenous pressure in hydrocephalus? 6) What causes normal-pressure hydrocephalus? 7) What causes low-pressure hydrocephalus? 8) What is the pathophysiology of slit ventricle syndrome? 9) What is the pathophysiological basis for neurological impairment in hydrocephalus, and to what extent is it reversible? 10) How is the brain of a child with hydrocephalus different from that of a young or elderly adult? Rigorous answers to these questions should lead to more effective and reliable treatments for this disorder.

PMID: 16572631

Proof of the patent subcutaneous fibrous tract in children with V-P shunt malfunction.

Kazan S, Açikbaş C, Rahat O, Tuncer R. Proof of the patent subcutaneous fibrous tract in children with V-P shunt malfunction. Child's Nervous System. 2000 Jun;16(6):351-6.

A connective tissue sheath that forms around the peritoneal catheter of silicone ventriculo-peritoneal (V-P) shunt tubing is quite often observed in children with V-P shunts. However, proof of the passage of cerebrospinal fluid (CSF) through these sheaths has been reported in only one published study to date. We present four cases associated with chronic malfunction of the V-P shunt peritoneal catheter. In these cases, CSF passage through the subcutaneous fibrous tract, which had a pericatheter connective tissue sheath, was demonstrated around the V-P shunt peritoneal catheter. In the first case the patient suffered intermittent headache attacks over a long period of time; abdominal migration of the peritoneal catheter was detected. The second patient, who had been asymptomatic in the follow-up period with an outgrown peritoneal catheter, was admitted with acute hydrocephalus symptoms. A peritoneal catheter disconnection was detected in another patient, who had had multiple shunt revisions previously. In the last case, an obstruction of the peritoneal catheter was detected. The existence of the subcutaneous fibrous tract and its function were demonstrated by radio-opaque shuntogram in two cases and radionuclide shuntogram in the other two cases. In all four cases V-P shunt revision was performed. Within this study, the possible passage of CSF through a fibrous tract in cases of migration, outgrowth, disconnection or obstruction of the peritoneal shunt catheter was demonstrated. In conclusion, patients with shunt malfunction with a well-grown pericatheter fibrous sheath who are either asymptomatic or minimally symptomatic and show no evidence of active ventricular dilatation on their cranial CT scan should not be regarded as having arrested hydrocephalus until radio-opaque or radionuclide shuntogram studies have been done.

PMID: 10933230

Evidence for a patent fibrous tract in fractured, outgrown, or disconnected ventriculoperitoneal shunts.

Clyde BL, Albright AL. Evidence for a patent fibrous tract in fractured, outgrown, or disconnected ventriculoperitoneal shunts. Pediatric Neurosurgery. 1995;23(1):20-5.

As cerebrospinal fluid (CSF) shunts function for several years, outgrowth and disconnection of the distal catheter are seen more frequently. Though a shunt revision is clearly indicated if patients are symptomatic, asymptomatic patients with a disconnection or who have outgrown the distal catheter may no longer require CSF diversion. This follows an assumption that the shunt is no longer functioning and, in an asymptomatic patient, no longer required. However, patent fibrous tracts have been postulated which may allow passage of CSF through disconnected or outgrown distal catheters. We have recently treated 2 patients with ventriculoperitoneal (VP) shunts with evidence of a persistent fibrous tract. A 13-year-old boy was asymptomatic for 2 years after radiographs revealed an outgrown distal VP shunt catheter, after which the acutely deteriorated and died from massive hydrocephalus, although the entire shunt was patent. Another 14-year-old boy who was profoundly retarded presented with subtle changes in his daily activity. Shunt radiographs revealed two disconnections and a broken valve, but a shunt tap revealed a normal opening pressure (OP). A radionuclide shuntogram revealed rapid passage of isotope through fibrous sheaths at the disconnections, and into the peritoneum. A shunt revision was performed and the patient returned to his previous level of health. Patients with outgrown or disconnected distal catheters may be asymptomatic and/or have normal OP, and must not be assumed to have arrested hydrocephalus. A ventricular pressure measurement and radionuclide shuntogram should be performed to rule out a patent persistent fibrous tract.

PMID: 7495662

Transient ventriculoperitoneal shunt malfunction after chronic constipation: case report and review of literature.

Muzumdar D, Ventureyra EC. Transient ventriculoperitoneal shunt malfunction after chronic constipation: case report and review of literature. Child's Nervous System. 2007 Apr;23(4):455-8. Epub 2006 Aug 29.

BACKGROUND: Significant constipation in patients with shunt-dependent hydrocephalus may often be enough to bring a subclinical shunt malfunction to clinical attention or even to be the cause of temporary distal peritoneal shunt malfunction. The treatment of the constipation may address the symptomatic shunt dysfunction so as to avoid operative intervention. The pathogenesis of distal shunt malfunction and its management in such a situation are discussed, and the relevant literature is briefly reviewed.

CASE REPORT: A 16-year-old young boy had shunt-dependent hydrocephalus secondary to prematurity and intraventricular hemorrhage at birth. He was chronic flaccid paraplegic and had a neurogenic bladder and bowel involvement. He presented with acute dull aching intermittent headaches, nausea, and constipation of short duration. There was no underlying shunt infection. CT brain showed dilated lateral ventricles. Shunt survey revealed a convoluted course and kink in the distal peritoneal catheter. After administration of a bowel enema, the headaches and nausea resolved over the next few hours, and the posttreatment CT showed significant decrease in ventricular size.

CONCLUSION: Chronic constipation is an important predisposing factor for distal malfunction in shunt-dependent hydrocephalus and should be ascertained in evaluation of a ventriculoperitoneal shunt malfunction. Appropriate treatment of significant constipation can relieve shunt malfunction and reestablish cerebrospinal fluid circulation. A shunt exploration can be avoided in such a situation. A close neurological monitoring of the patient is essential during the course of treatment. An interdisciplinary approach between concerned medical specialties and enhanced awareness is mandatory to ensure appropriate bowel management.

PMID: 17009006

Constipation as a reversible cause of ventriculoperitoneal shunt failure. Report of two cases.

Powers CJ, George T, Fuchs HE. Constipation as a reversible cause of ventriculoperitoneal shunt failure. Report of two cases. Journal of Neurosurgery. 2006 Sep;105(3 Suppl):227-30.

Ventriculoperitoneal (VP) shunt failure is a common problem encountered by pediatric neurosurgeons. The majority of such failures are due to obstruction of the device. Conditions in which intraabdominal pressure is chronically elevated, such as pregnancy, have been associated with shunt failure. Chronic constipation may also result in abnormally elevated intraabdominal pressure and may be an underrecognized cause of distal VP shunt failure. The authors describe the cases of two children who presented with clinical and imaging evidence of VP shunt failure and who were also severely constipated. Treatment of their constipation resulted in both clinical and imaging-documented resolution of their shunt failure.

PMID: 16970237

Complications and pitfalls of neuroendoscopic surgery in children.

Peretta P, Ragazzi P, Galarza M, Genitori L, Giordano F, Mussa F, Cinalli G. Complications and pitfalls of neuroendoscopic surgery in children. Journal of Neurosurgery. 2006 Sep;105(3 Suppl):187-93.

OBJECT: Neuroendoscopic surgery is being used as an alternative to traditional shunt surgery and craniotomy in the management of hydrocephalus and intracranial fluid-filled cavities. In this study, the authors evaluated the incidence and type of complications occurring after neuroendoscopic procedures that were performed in a consecutive series of pediatric patients at a single institution to determine the effectiveness of neuroendoscopy in such patients.

METHODS: Four hundred ninety-five neuroendoscopic procedures were consecutively performed in 450 pediatric patients at one institution over a 10-year period. Charts were retrospectively reviewed. A complication was defined as follows: 1) any postoperative neurological deficit that was not observed before surgery; 2) any event occurring during surgery that resulted in the procedure being aborted; or 3) any adverse event occurring within 7 days postsurgery that resulted in a modification of the normal postoperative care. However, headache, vomiting, and fever without cerebrospinal fluid (CSF) pleocytosis were not considered complications. Complications were observed in 40 (8.1%) of 495 procedures. Two patients had two complications. One patient died of diffuse brain edema following endoscopic biopsy sampling of a basal ganglia tumor (mortality rate 0.2%). Other complications observed were abandonment of the procedure in eight cases, CSF leakage in 11 (with associated wound infection in one), intraventricular hemorrhage in six (with external drainage needed in four), intraparenchymal hemorrhage in three, subdural collection in eight (with subdural-peritoneal shunt placement needed in seven), transient oculomotor palsy in two, and transient hemiparesis in one.

CONCLUSIONS: Many complications can be avoided by determining the correct diagnosis and using suitable techniques and instruments. Most complications can be managed conservatively and do not produce long-term morbidity. Complex procedures in most patients and simple procedures in patients with preoperative risk factors carry the highest hazard. Every attempt should be made to optimize the surgical technique. The most serious and potentially the most lethal complication remains arterial bleeding from injury to the basilar artery complex.

PMID: 16970231

Management of shunt infections: a multicenter pilot study.

Kestle JR, Garton HJ, Whitehead WE, Drake JM, Kulkarni AV, Cochrane DD, Muszynski C, Walker ML. Management of shunt infections: a multicenter pilot study. Journal of Neurosurgery. 2006 Sep;105(3 Suppl):177-81.

OBJECT: Approximately 10% of cerebrospinal fluid (CSF) shunt operations are associated with infection and require removal or externalization of the shunt, in-hospital treatment with antibiotic agents, and insertion of a new shunt. In a previous survey, the authors identified substantial variation in the duration of antibiotic therapy as well as the duration of hospital stay. The present multicenter pilot study was undertaken to evaluate current strategies in the treatment of shunt infection.

METHODS: Patients were enrolled in the study if they had a successful treatment of a CSF shunt infection proved by culture of a CSF specimen. Details of their care and the incidence of culture-proved reinfection were recorded. Seventy patients from 10 centers were followed up for 1 year after their CSF shunt infection. The initial management of the infection was shunt externalization in 17 patients, shunt removal and external ventricular drain insertion in 50, and antibiotic treatment alone in three. Reinfection occurred in 18 patients (26%). Twelve of the 18 reinfections were caused by the same organism and six were due to new organisms. The treatment time varied from 4 to 47 days, with a mean of 17.4 days for those who later experienced a reinfection compared with 16.2 days for those who did not. The most common organism (Staphylococcus epidermidis, 34 patients) was associated with a reinfection rate of 29% and a mean treatment time of 12.8 days for those who suffered reinfection and 12.5 days for those who did not.

CONCLUSIONS: Reinfection after treatment of a CSF shunt infection is alarmingly common. According to the data available, the incidence of reinfection does not appear to be related to the duration of antibiotic therapy.

PMID: 16970229

The effects of detethering on the urodynamics profile in children with a tethered cord.

Hsieh MH, Perry V, Gupta N, Pearson C, Nguyen HT. The effects of detethering on the urodynamics profile in children with a tethered cord. Journal of Neurosurgery. 2006 Nov;105(5 Suppl):391-5.

OBJECT: Tethering of the spinal cord is a pathological fixation of the cord in the vertebral column that can result in neurogenic bladder dysfunction and other neurological problems. It occurs in patients with closed spinal dysraphisms and those in whom postoperative scarring develops following spina bifida closure procedures. The authors of this study sought to determine the effects of detethering on the urodynamic profile of children with a tethered cord.

METHODS: The authors retrospectively reviewed the records of children who underwent surgical release of a tethered cord at a single institution between 2001 and 2003. They identified 17 children (nine girls and eight boys) who had undergone both preoperative and postoperative urodynamic evaluation. Preoperatively, 10 (59%) of the children with a tethered cord had abnormal urodynamic study (UDS) results. Only two (20%) of these patients had urological symptoms. All seven patients with normal preoperative UDS results had normal UDS results after detethering. In addition, in five (50%) of the 10 children with abnormal preoperative UDS results, the postoperative UDS demonstrated improved or normal urodynamics.

CONCLUSIONS: Because more than half of the children who underwent detethering were found to have abnormal preoperative UDS results, preoperative urodynamic evaluation should be performed in all cases in which detethering is considered. With regard to voiding function, detethering is relatively safe for children with normal preoperative UDS results. In children with abnormal preoperative UDS results, detethering may lead to improvement or even normalization of voiding, especially if the procedure is performed prior to 1 year of age. Finally, children with anorectal anomalies and a tethered cord may represent a subset of patients who are particularly likely to experience urodynamic improvement after detethering.

PMID: 17328264

Evaluation and management of shunt infections in children with hydrocephalus.

Duhaime AC. Evaluation and management of shunt infections in children with hydrocephalus. Clinical Pediatrics 2006 Oct;45(8):705-13.

Shunt infections constitute one of the main risks of shunt surgery for hydrocephalus, which is the single most common type of surgery performed by pediatric neurosurgeons. Infectious complications are responsible for increased morbidity and mortality, lengthy hospitalizations, and high cost. Most modern series report infection rates approaching 10% of all shunt procedures. Despite the high incidence of this complication, optimal management is still unknown, and research on prevention has been hampered by single-institution series and small numbers. This article will review the history, causes, presentation, management, and outcome from shunt infections in children. Pitfalls in diagnosis and management will be reviewed. Finally, prevention strategies and research questions still remaining in this area will be outlined.

PMID: 16968955

Shunt infection: is there a near-miss scenario?

Thompson DN, Hartley JC, Hayward RD. Shunt infection: is there a near-miss scenario? Journal of Neurosurgery. 2007 Jan;106(1 Suppl):15-9.

OBJECT: The aim of this study was to establish whether microbiological contamination at the time of shunt insertion can be detected and used to predict the likelihood of subsequent shunt infection.

METHODS: A prospective study of pediatric patients undergoing primary shunt insertion was undertaken. Following the protocol devised for this study, three swab samples were collected from the surgical wounds during each procedure. These samples were incubated and subcultured, and the isolates were identified and stored. In patients who subsequently presented with clinical evidence of shunt infection, cerebrospinal fluid (CSF) was analyzed using microscopy, tissue cultures, and sensitivity testing. The organisms isolated at the time of shunt insertion and those responsible for subsequent shunt infection were then compared. The study population consisted of 107 pediatric patients. Because one patient underwent placement of an additional contralateral shunt system, there were 108 total shunt insertions yielding 325 swab samples. Organisms were identified in cultures of 50 swab samples (15%) obtained in 40 patients (37%). In seven of these 40 patients (17.5%) a CSF infection subsequently developed. In only one patient was the infectious organism the same as that isolated from the swab specimens. In an additional six patients (8.8%) a CSF infection occurred despite the lack of growth in the cultures from intraoperative swab samples.

CONCLUSIONS: The organisms responsible for shunt infection were rarely detected in the operative wound at the time of shunt insertion, leading the authors to conclude that the vulnerable period for bacterial colonization of shunts may not be restricted to the operative procedure as is commonly believed, but may extend throughout the postoperative period of wound healing. These findings have implications not only for a better understanding of the cause of shunt infections but also for the development of strategies to prevent them.

PMID: 17233307

Intelligence quotient in children with meningomyeloceles: a case-control study.

Nejat F, Kazmi SS, Habibi Z, Tajik P, Shahrivar Z. Intelligence quotient in children with meningomyeloceles: a case-control study. Journal of Neurosurgery. 2007 Feb;106(2 Suppl):106-10.

OBJECT: Meningomyelocele (MMC) is a common central nervous system birth defect. As one of many problems facing patients with MMC, learning disabilities are often overlooked. The aim of this study was to evaluate IQs in a group of children with MMCs and determine if a correlation exists between intelligence level and the presence of an MMC and/or its complications.

METHODS: A case-control study was conducted at the Children's Hospital Medical Center in Tehran, Iran, from December 2004 through December 2005. The patient group included 50 children with MMC from 5 to 12 years of age who were referred to the authors' institution for treatment of complications or for follow up after surgery for MMC closure. The patient group was individually matched for age and sex with a control group of 50 children referred to the hospital for other reasons and who did not have MMC or other neurological abnormalities. The IQs in all children in this study were evaluated using the Ravens Progressive Matrices test. The children in both groups were similar in the socioeconomic status of the family (p = 0.347) and educational status of the father (p = 0.117) and mother (p = 0.439). Patient age at the time of surgery for MMC closure varied from 1 day to 96 months (mean 4.1 months). Only 20% of the patients with MMC could walk with a normal gait. Forty-six percent of the patients had undergone placement of a ventriculoperitoneal shunt, and half of these patients experienced shunt-related complications; 72% of the children in the patient group were completely incontinent for both urine and feces. The IQ results obtained in the patient group ranged from 73 to 134 with a mean (+/- standard deviation) of 96.62 +/- 13.01. In the control group the IQ range was 70 to 128, and the mean was 104.82 +/- 12.30. Compared with the control group there was a statistically significant correlation between having an MMC and having a lower IQ (p < 0.001, paired t-test).

CONCLUSIONS: Although the average IQ in the patient group was significantly lower than that in the control group, it is important to note that all children in the patient group had an average or above-average IQ. In contrast with the results reported in other studies, earlier repair of the MMC, the presence of a shunt or shunt-related complications, walking difficulty, and the spinal level of the lesion did not correlate significantly with IQs. Therefore, the lower IQ and reduced cognitive levels noted in these patients result from the disease process itself and not from the associated complications.

PMID: 17330535

Experience with the Strata valve in the management of shunt overdrainage.

Kondageski C, Thompson D, Reynolds M, Hayward RD. Experience with the Strata valve in the management of shunt overdrainage. Journal of Neurosurgery. 2007 Feb;106(2 Suppl):95-102.

OBJECT: The overdrainage of cerebrospinal fluid (CSF) in children with shunt-treated hydrocephalus may cause chronic disabling symptoms and require repeated surgery. Externally adjustable valves offer a noninvasive way of altering the valve opening pressure. The authors report on their experience with using the Strata valve in the management of symptomatic CSF overdrainage.

METHODS: The authors treated 24 patients with symptomatic CSF overdrainage by inserting a Strata valve. The severity of symptoms was graded, and the frequency of hospital visits and shunt operations was recorded before and after insertion of the valve. Additionally, results of brain imaging and intracranial pressure monitoring were reviewed. Nineteen patients (79.2%) had severe symptoms at the time of the insertion; 1 year after Strata valve insertion only one patient (4.17%) still suffered severe symptoms. The number of hospital admissions was 3.38/patient/year before placement and 1.21 for the 1st year, 1 for the 2nd, and 0.4 for the 3rd postoperative year. The number of operations was 3.42/patient/year during the year before placement of the valve, and then 0.71 for the 1st, 0.56 for the 2nd, and 0.25 for the 3rd postoperative years. During the 1st year after placement of the Strata valve, the settings were changed 2.79 times/patient/year, 1.29 for the 2nd, and 1.33 times/patient/year for the 3rd year.

CONCLUSIONS: The Strata valve was effective in improving the symptoms of overdrainage in the majority of patients in this series. The number of hospital admissions and operations for valve malfunction was reduced.

PMID: 17330533

Fetal spina bifida in a mouse model: loss of neural function in utero.

Stiefel D, Copp AJ, Meuli M. Fetal spina bifida in a mouse model: loss of neural function in utero. Journal of Neurosurgery. 2007 Mar;106(3 Suppl):213-21.

OBJECT: The devastating neurological deficit associated with myelomeningocele has previously been assumed to be a direct and inevitable consequence of the primary malformation-failure of neural tube closure. An alternative view is that secondary damage to the pathologically exposed spinal cord tissue in utero is responsible for the neurological deficiency. If the latter mechanism were shown to be correct, it would provide an objective rationale for the performance of in utero surgery for myelomeningocele, because coverage of the exposed spinal cord could be expected to alleviate or perhaps prevent neurodegeneration. To examine this question, the authors studied the development of neuronal connections and neurological function of mice during fetal and neonatal stages in a genetic model of exposed lumbosacral spina bifida.

METHODS: The persistently exposed spinal cord of mouse fetuses carrying both curly tail and loop-tail mutations exhibited essentially normal anatomical and functional hallmarks of development during early gestation (embryonic Days 13.5-16.5), including sensory and motor projections to and from the cord. A significant proportion of fetuses with spina bifida at early gestation exhibited sensorimotor function identical to that seen in age-matched healthy controls. However, at later gestational stages, increasing neurodegeneration within the spina bifida lesion was detected, which was paralleled by a progressive loss of neurological function.

CONCLUSIONS: These findings provide support for the hypothesis that neurological deficit in human myelomeningocele arises following secondary neural tissue destruction and loss of function during pregnancy.

PMID: 17465388

Double spinal dysraphism. Report of three cases

Keshavarzi S, Nejat F, Kazemi H. Double spinal dysraphism. Report of three cases. Journal of Neurosurgery. 2007 Apr;106(4 Suppl):316-8.

The simultaneous presence of multiple spinal neural tube defects is unusual. There have been only a few of these cases reported in the literature. The authors report on three cases of double spina bifida cystica. One patient had two myelomeningoceles (MMCs) at the cervical and lumbosacral regions, one was noted to have both thoracolumbar and sacral defects, and the third presented with double MMCs at lumbar and lumbosacral levels. All three neonates in these cases underwent surgical treatment and ventriculoperitoneal (VP) shunt insertion for associated hydrocephalus. One child died at the age of 2 months despite a well-functioning VP shunt. The other two patients had no complications. Current models of neural tube closure do not thoroughly explain the mechanisms of multiple spinal dysraphism, but the multisite closure model provides a better understanding of caudal neural tube closure than other closure-site models.

PMID: 17465369

Endovascular placement of a ventriculoatrial shunt. Technical note.

Gonzalez LF, Kim L, Rekate HL, McDougall CG, Albuquerque FC. Endovascular placement of a ventriculoatrial shunt. Technical note. Technical note. Journal of Neurosurgery. 2007 Apr;106(4 Suppl):319-21.

Atrial shunt revision surgeries are sometimes difficult due to venous occlusion and neck scarring. A direct approach guided by venography facilitates exposure and guarantees accurate placement of the distal catheter. Five patients with complicated histories of shunt malfunction were treated using an endoscope-assisted technique. The distal end of an atrial catheter was advanced into the atrium after having been connected to a venous catheter of a slightly smaller diameter than the one previously advanced from the femoral vein through the atrium. Once the position of the atrial catheter was confirmed fluoroscopically, the venous catheter was detached and removed. No complications developed in any patient. This endoscope-assisted technique offers three advantages: it demonstrates the patency of the jugular vein through venography, facilitates identification of the internal jugular vein in the neck, and provides a quick way to confirm that the distal end of the atrial catheter has been placed correctly. This technique should be considered for use in patients with a history of failed atrial shunts.

PMID: 17465370

Ascites and abdominal pseudocysts following ventriculoperitoneal shunt surgery: variations of the same theme.

Kariyattil R, Steinbok P, Singhal A, Cochrane DD. Ascites and abdominal pseudocysts following ventriculoperitoneal shunt surgery: variations of the same theme. Journal of Neurosurgery. 2007 May;106(5 Suppl):350-3.

OBJECT: Ascites and abdominal pseudocysts are two complications that can occur following placement of a ventriculoperitoneal (VP) shunt. Although various factors have been implicated, the exact pathogenesis of the two conditions remains elusive. To the authors' knowledge, there are no studies in which these two obviously related conditions have been compared.

METHODS: The authors retrospectively reviewed the cases of children with abdominal complications caused by a VP shunt. There were 15 patients who developed a pseudocyst and five patients who developed ascites. The cases were analyzed to identify common and distinguishing factors that may help in identifying the mechanism involved. Abdominal symptoms were the mode of presentation for patients with ascites, whereas shunt malfunction was the mode of presentation in 60% of those with pseudocysts. Culture-proven infection, abdominal surgery, and the number of revisions seemed to be more common in cases with pseudocysts than in ascites. The fluid in ascites was found to be a transudate irrespective of the origin of hydrocephalus. Alternative drainage sites were required in the treatment of patients with ascites, and reimplantation in the peritoneum was possible in 66.7% of those with pseudocysts. In the long-term, however, peritoneal reimplantation was possible in three of the five patients with ascites.

CONCLUSIONS: Abdominal pseudocysts and ascites, after VP shunt treatment, are distinct conditions with different modes of presentation and findings during examination of fluid, and therefore they require different management strategies.

PMID: 17566200

Predicting slitlike ventricles in children on the basis of baseline characteristics at the time of shunt insertion

Kan P, Walker ML, Drake JM, Kestle JR. Predicting slitlike ventricles in children on the basis of baseline characteristics at the time of shunt insertion. Journal of Neurosurgery. 2007 May;106(5 Suppl):347-9.

OBJECT: Slit ventricle syndrome (SVS) is a delayed complication of shunt insertion and occurs only in children with slitlike ventricles after shunt placement. Although SVS appears to be related to early shunt placement, its predisposing factors are largely unknown.

METHODS: Baseline data in 737 children who had received shunts were obtained from the databases of two previous clinical trials. Ventricular size before shunt placement and at the last routine follow up was measured using the frontooccipital horn ratio (FOHR). Ventricles with an FOHR less than or equal to 0.2 at follow up were classified as slitlike ventricles. A univariate analysis was performed on data obtained in children with more than 1 year of clinical and radiographic follow up to identify risk factors for developing slitlike ventricles. These results were entered into a multivariate analysis to identify independent predictors of slitlike ventricles. Two hundred forty-four children had more than 1 year of clinical and radiographic follow-up data. The 23 patients (9.4%) who developed slitlike ventricles had shunts inserted at a younger age (42 compared with 134 days, p = 0.09) and were more likely to have developed hydrocephalus secondary to infection (37.5%), head injury (25.0%), or aqueductal stenosis (22.2%). Slitlike ventricles were seen in 10.8% of patients with differential-pressure valves, 10.5% of patients with Delta valves, and 3.6% of patients with Orbis-Sigma valves (p = 0.007). Regression analysis supported the role of the valve type in developing slitlike ventricles.

CONCLUSIONS: Age at shunt insertion and valve type appear to be the modifiable risk factors for developing slitlike ventricles. If the authors of subsequent studies can further validate these conclusions, slow-draining valves and delayed shunt insertion might be used to decrease the incidence of slitlike ventricles and SVS.

PMID: 17566199

Long-term outcomes in patients with treated childhood hydrocephalus.

Gupta N, Park J, Solomon C, Kranz DA, Wrensch M, Wu YW. Long-term outcomes in patients with treated childhood hydrocephalus. Journal of Neurosurgery. 2007 May;106(5 Suppl):334-9.

OBJECT: The goal in this study was to determine the long-term effects of childhood hydrocephalus.

METHODS: A patient-reported survey completed by 1953 participants was used to collect data in a subgroup of 1459 individuals who had been treated for hydrocephalus in childhood. Data on shunt complications, including total shunt revisions and infections, were examined in those whose hydrocephalus had been diagnosed at least 10 years earlier (718 patients). Social and functional outcomes were examined in patients who were 20 years of age or older at the time of survey completion (403 individuals). Specific questions addressed the presence of depression, the patient's marital status, independent living arrangements, and the educational level attained. Shunt complications were common; 54% of patients had four or more shunt revisions, and 9% had three or more shunt infections. Depression requiring treatment occurred in 45% of participants. Other measures of social functioning all reflected a major impact of childhood hydrocephalus. In general, a worse outcome was found in patients whose hydrocephalus was diagnosed before 18 months of age.

CONCLUSIONS: The lifelong morbidity associated with shunt placement to treat childhood hydrocephalus is substantial, and it includes shunt-related complications and comorbidities that adversely affect social functioning.

PMID: 17566197

Outcome following multiple repeated spinal cord untethering operations.

Maher CO, Goumnerova L, Madsen JR, Proctor M, Scott RM. Outcome following multiple repeated spinal cord untethering operations. Journal of Neurosurgery. 2007 Jun;106(6 Suppl):434-8.

OBJECT: Patients who have undergone prior myelomeningocele or lipomyelomeningocele repair may present with symptomatic retethering of the spinal cord. In some cases, symptomatic tethering may recur after previous untethering operations. The expected outcome following repeated untethering in a patient after two or more prior untethering operations is not well described.

METHODS: The authors examined surgical indications, techniques, and outcomes for 30 repeated untethering operations in 22 patients who had undergone a previous repair of the primary spinal disorder and at least two subsequent untethering operations. The mean age at repeated untethering was 12.3 years. Presenting symptoms were pain (70%), weakness (70%), urinary symptoms (57%), and sensory changes (27%). The mean duration of symptoms was 7.5 months, and a longer symptomatic interval correlated with an increased number of prior operations. Total circumferential untethering was accomplished in 11 cases (37%). Postoperative symptomatic improvement was noted most often for pain (81%), and less often for urinary symptoms (53%) and weakness (48%). Complications included postoperative cerebrospinal fluid leakage or pseudomeningocele and new postoperative lower-extremity dysesthesia in five cases (17%). An increasing number of prior untethering operations was associated with a worse result for pain relief and a greater chance of significant morbidity.

CONCLUSIONS: Multiple repeated untethering operations offer symptomatic relief to well-selected patients with this condition.

PMID: 17566398

Longstanding overt ventriculomegaly in adults: pitfalls in treatment with endoscopic third ventriculostomy.

Rekate HL. Longstanding overt ventriculomegaly in adults: pitfalls in treatment with endoscopic third ventriculostomy. Neurosurgical Focus. 2007 Apr 15;22(4):E6.

OBJECT: The recently described condition of longstanding overt ventriculomegaly in adults (LOVA) has not been defined in terms of the need for intervention, timing of intervention, and ideal treatment. The purpose of this review was to evaluate the role of endoscopic third ventriculostomy (ETV) in the treatment of LOVA.

METHODS: Data collected in six patients with LOVA who had undergone ETV were reviewed retrospectively in terms of the definition of treatment success, rates of success, complications, and outcome. All six patients presented with headache disorders. In all patients, triventricular hydrocephalus had been diagnosed as aqueductal stenosis, and head circumference measurements were above the 98th percentile. All six had undergone successful ETV as documented by the free flow of cerebrospinal fluid into the basal cisterns, which remained open throughout the follow-up period. After the procedure, one patient experienced a mild degree of difficulty with short-term memory. Five patients remained symptomatic or had symptoms requiring further treatment 3 months to 3 years after ETV. Four patients received ventriculoperitoneal shunts, and one underwent venous stenting for high intracranial pressure after successful ETV. In two patients in whom aqueductal stenosis had been diagnosed, the sylvian aqueduct was patent after the procedure.

CONCLUSIONS: In LOVA patients who present with headaches, ETV may not lead to improvement in the headaches. Despite the presence of triventricular hydrocephalus, closure of the aqueduct may be a secondary phenomenon, and flow through the aqueduct may be reestablished after ETV. If intracranial hypertension persists after successful ETV, its cause may be increased venous sinus pressure.

PMID: 17613195

Embryology of myelomeningocele and anencephaly

Dias MS, Partington M. Embryology of myelomeningocele and anencephaly. Neurosurgical Focus. 2004 Feb 15;16(2):E1. Review.

The authors review current views on of the embryogenesis of the neural tube defects (NTDs) myelomeningocele and anencephaly. In this context, the following four approaches to the study of NTDs are discussed: normal morphogenesis and timing of early human neural development from conception to the ascent of the conus medullaris; mechanical and molecular biology of neural tube closure derived from experimental and animal models; morphological and biomechanical features of the NTDs myelomeningocele and anencephaly; and the experimental evidence for the importance of both genetic and environmental influences on human NTDs. Although considerable insight into both normal neural tube closure and the factor(s) by which this process may be disrupted has been reported in recent years, the exact mechanism(s) by which human myelomeningoceles and anencephaly arise remain elusive.

PMID: 15209484