Posterior Cranial Fossa Volume in Patients with Rickets: Insights into the Increased Occurrence of Chiari I Malformation in Metabolic Bone Disease

A Novel Phenotype of Calvarial Thickening and Increased Rates of Premature Calvarial Suture Closure in Children With Chronic Lung Disease

PURPOSE

The purpose of this study was to characterize a novel type of calvarial thickening and provide objective measurements of skull thickness and calvarial suture morphology in patients with bronchopulmonary dysplasia.

METHODS

Infants with severe bronchopulmonary dysplasia who also had undergone computed tomography (CT) scans were identified from the neonatal chronic lung disease program database. Thickness analysis was performed using Materialise Mimics.

RESULTS

The chronic lung disease team treated 319 patients during the study interval of which, 58 patients (18.2%) had head CT available. Twenty-eight (48.3%) were found to have calvarial thickening. The rate of premature suture closure in the study population was 36.2% (21 of 58 patients), with 50.0% of affected cohort having evidence of premature suture closure on the first CT scan. Multivariate logistic regression identified 2 risk factors, requiring invasive ventilation at 6 months of age and fraction of inspired oxygen requirement at 6 months of age. Increased head circumference at birth protected against the development of calvarial thickening.

CONCLUSIONS

We have described a novel subset of patients with chronic lung disease of prematurity who have calvarial thickening with remarkably high rates of premature closure of cranial sutures. The exact etiology of the association is unknown. In this patient population with radiographic evidence of premature suture closure, operative decision should be made after considering unequivocal evidence of elevated intracranial pressure or dysmorphology and balanced against the risk of the procedure.

Chiari I malformation in defined genetic syndromes in children: are there common pathways?

PURPOSE

Chiari malformation type I (CMI) is a common pediatric neurologic anomaly that can be associated with a variety of genetic disorders; however, it is not always clear whether the observed associations are real or random. The knowledge of the real associations could provide useful guidance to clinicians. Furthermore, it could be of help to better understand the still unknown genetic etiology of CMI.

METHODS

With the aim of implementing such insights, we retrospectively reviewed clinical, neuroradiological, and genetic data of patients harboring CMI evaluated at the Child Neurology Unit of our institution between January 2008 and December 2018.

RESULTS

The cohort consists of 205 patients (111 males and 94 females), with a mean age at diagnosis of 6.3 years (range 0-18 years). 188 patients completed an average follow-up period of 5.2 years (range one month-18 years). Mean age at last assessment was 11.4 years (range nine months-23 years). 127 (62%) children have been classified as syndromic due to the presence of neurodevelopmental disorders, phenotypic anomalies, or malformations. Among syndromic CMI children, a molecular diagnosis was identified in 35/127 (27.6%) (20 males and 15 females). The most common diagnoses were syndromic craniosynostosis in 8/35 children (22.9%), among which sevenare FGFR-related and one ERF-related craniosynostosis; disorders of the RAS/MAPK pathway, termed RASopathies or RAS/MAPK syndromes in 9/35 (25.7%); disorders of the PTEN-PI3K/AKT signal transduction cascade, termed PTENopathies in 3/35 children (8.6%); and chromosomal rearrangements in 6/35 patients (17.1%), two of whom with del16p11.2.

CONCLUSIONS

We polarized our attention on the defined genetic diagnoses focusing not only on the phenotypic hallmarks but also on the phenotypic overlapping features. In addition, we discussed the pathophysiological mechanisms leading to progressive cerebellar ectopia and the involved molecular pathways. Along with the recent literature evidence, we suppose that interactions between FGFR and RAS/MAPK pathway and between RAS/MAPK and PTEN-PI3K/AKT pathways could explain some phenotypic overlapping features and could have a significant role in the pathogenesis of CMI.

The growth of the posterior cranial fossa in FGFR2-induced faciocraniosynostosis: A review

BACKGROUND

The growth of the posterior fossa in syndromic craniostenosis was studied in many papers. However, few studies described the pathophysiological growth mechanisms in non-operated infants with fibroblast growth factor receptor (FGFR) type 2 mutation (Crouzon, Apert or Pfeiffer syndrome), although these are essential to understanding cranial vault expansion and hydrocephalus treatment in these syndromes.

OBJECTIVE

A review of the medical literature was performed, to understand the physiological and pathological growth mechanisms of the posterior fossa in normal infants and infants with craniostenosis related to FGFR2 mutation.

DISCUSSION

Of the various techniques for measuring posterior fossa volume, direct slice-by-slice contouring is the most precise and sensitive. Posterior fossa growth follows a bi-phasic pattern due to opening of the petro-occipital, occipitomastoidal and spheno-occipital sutures. Some studies reported smaller posterior fossae in syndromic craniostenosis, whereas direct contouring studies reported no difference between normal and craniostenotic patients. In Crouzon syndrome, synchondrosis fusion occurs earlier than in normal subjects, and follows a precise pattern. This premature fusion in Crouzon syndrome leads to a stenotic foramen magnum and facial retrusion.

Chiari I Malformation and Basilar Invagination in Fibrous Dysplasia: Prevalence, Mechanisms, and Clinical Implications

Fibrous dysplasia (FD) is a mosaic disorder of benign fibro-osseous lesions, which may be associated with extraskeletal features as part of McCune-Albright syndrome (MAS). Cranial base abnormalities, including Chiari I malformation (CM1), in which the cerebellum extends below the foramen magnum, and secondary basilar invagination (BI), in which the odontoid prolapses into the posterior cranial fossa, are potentially serious complications of metabolic bone disorders. The purpose of this study was to determine the prevalence, natural history, and risk factors for CM1 and BI in patients with FD/MAS, and to determine mechanisms of cranial base deformities. Clinical and radiographic data from subjects in an FD/MAS natural history study were evaluated and compared to normal controls. In 158 patients with craniofacial FD, 10 (6.3%) cases of CM1 and 12 (7.6%) cases of BI were diagnosed. No cranial base abnormalities were identified in 10 control subjects. Craniomorphometric and volumetric analyses identified cranial constriction and cranial settling as the primary mechanisms of cranial base abnormalities, whereas intracranial hypertension was a contributing factor in a minority of subjects. Longitudinal analyses found progression of odontoid position with age, but no progression of tonsillar position. No endocrinopathies were associated with CM1. MAS endocrinopathies associated with BI included hyperthyroidism (odds ratio [OR] 12.0; 95% confidence interval [CI], 2.9 to 55.6; p < 0.01), precocious puberty (OR 5.6; 95% CI, 1.2 to 26.0; p < 0.05), and hypophosphatemia (OR 7.7; 95% CI, 1.9 to 27.0; p < 0.01). Scoliosis was associated with both CM1 (OR 4.8; 95% CI, 1.1 to 22.8; p < 0.05) and BI (OR = infinity; 95% CI, 4.7 to infinity; p < 0.01). This study successfully characterized cranial base abnormalities in FD/MAS and the pathophysiological connection between them. These findings support routine screening for cranial base abnormalities in patients with craniofacial FD, as well as aggressive management of contributory risk factors. © 2018 American Society for Bone and Mineral Research.

Embryology of the craniocervical junction and posterior cranial fossa, part II: Embryogenesis of the hindbrain

Although pathology of the hindbrain and its derivatives can have life altering effects on a patient, a comprehensive review on its embryology is difficult to find in the peer-reviewed medical literature. Therefore, this review article, using standard search engines, seemed timely. The embryology of the hindbrain is complex and relies on a unique timing of various neurovascular and bony elements. Derailment of these developmental processes can lead to a wide range of malformations such as the Chiari malformations. Therefore, a good working knowledge of this embryology as outlined in this review of the hindbrain is important for those treating patients with involvement of this region of the central nervous system. Clin. Anat. 31:488-500, 2018. © 2018 Wiley Periodicals, Inc.

Human Foramen Magnum Area and Posterior Cranial Fossa Volume Growth in Relation to Cranial Base Synchondrosis Closure in the Course of Child Development

BACKGROUND

To date, no study has compared the evolution of the foramen magnum area (FMA) and the posterior cranial fossa volume (PCFV) with the degree of cranial base synchondrosis ossification.

OBJECTIVE

To illustrate these features in healthy children.

METHODS

The FMA, the PCFV, and the ossification of 12 synchondroses according to the Madeline and Elster scale were retrospectively analyzed in 235 healthy children using millimeter slices on a computed tomography scan.

RESULTS

The mean FMA of 6.49 cm in girls was significantly inferior to the FMA of 7.67 cm in boys (P < .001). In both sexes, the growth evolved in a 2-phase process, with a phase of rapid growth from birth to 3.75 years old (yo) followed by a phase of stabilization. In girls, the first phase was shorter (ending at 2.6 yo) than in boys (ending at 4.33 yo) and proceeded at a higher rate. PCFV was smaller in girls (P < .001) and displayed a biphasic pattern in the whole population, with a phase of rapid growth from birth to 3.58 yo followed by a phase of slow growth until 16 yo. In girls, the first phase was more active and shorter (ending at 2.67 yo) than in boys (ending at 4.5 yo). The posterior interoccipital synchondroses close first, followed by the anterior interoccipital and occipitomastoidal synchondroses, the lambdoid sutures simultaneously, then the petro-occipital and spheno-occipital synchondroses simultaneously.

CONCLUSION

The data provide a chronology of synchondrosis closure. We showed that FMA and PCFV are constitutionally smaller in girls at birth (P ≤ .02) and suggest that a sex-related difference in the FMA is related to earlier closure of anterior interoccipital synchondroses in girls (P = .01).

ABBREVIATIONS

AIOS, anterior interoccipital synchondrosesFMA, foramen magnum areaLS, lambdoid suturesOMS, occipitomastoidal synchondrosesPCFV, posterior cranial fossa volumePIOS, posterior interoccipital synchondrosesPOS, petro-occipital synchondrosesSOS, spheno-occipital synchondrosisyo, years old.

Histological study of the occipital bone from patients with Chiari I malformation

BACKGROUND

This study is focused on the histologic characteristics of occipital bone removed during Chiari I decompression in the hope of discovering unique features that may be related to the pathogenesis of this condition.

METHODS

Ten consecutive pediatric patients with Chiari I malformation underwent standard posterior fossa decompression surgery. Bone that was removed from the posterior fossa was sent for histological examination. Bone from age-matched controls also underwent histological analysis.

RESULTS

For all study and control specimens, bony samples were found to be made up of dense lamellar bone without marrow elements. In all aspects, histologically, the bone tissue had a normal appearance compared to control samples.

CONCLUSIONS

Although many authors have mentioned that the occipital bone in patients with Chiari I malformation is abnormal on imaging or at operation (e.g., thinned, thickened), based on our study, there is no histological difference between the occipital bone removed at operation and controls.

Morphometric Analysis of Predictors of Cervical Syrinx Formation in the Setting of Chiari I Malformation

BACKGROUND/AIMS

We performed a morphometric analysis of Chiari I malformations to look for predictors of cervical syrinx formation.

METHODS

Eighteen patients with Chiari I malformation and associated cervical syrinx and 16 patients with Chiari I malformation without associated cervical syrinx were included in the study. Chiari I size was obtained from the radiology report; foramen magnum diameter, cerebellar volume, posterior fossa volume and intracranial volume were calculated using OsiriX software, and average measurements were compared between the two groups.

RESULTS AND CONCLUSION

Patients with Chiari I with syrinx had an average tonsillar descent of 13.03 ± 5.31 mm compared to 9.25 ± 3.31 mm in the Chiari I without syrinx group (p < 0.05). Patients with Chiari I and syrinx also showed increased cerebellar crowding with a higher cerebellar volume to posterior fossa volume ratio; however, this difference was not significant (0.83 vs. 0.81; p = 0.1872). No difference between groups was found in posterior fossa volume, intracranial volume and foramen magnum diameter. Therefore, only Chiari I size based on the extent of tonsillar herniation was found to be a determinant of cervical syrinx formation.

Relationship between pharyngitis and peri-odontoid pannus: A new etiology for some Chiari I malformations?

The pathophysiology underlying Chiari I malformations (CIMs) provides room for debate with several theories attempting to address this issue. We retrospectively reviewed many of our past patients with pediatric CIMs (specifically, those with peri-odontoid pannus), and present a hypothesis for the development of the malformation in some of said patients. Our experience with the pediatric CIM has shown that almost 1 in 20 patients who present with symptoms is found to have a peri-odontoid pannus. These masses ranged in size from 4 to 11 mm in diameter. Forty percent had a history of clinically significant pharyngitis or pharyngeal abscess. Pannus formation around the dens (odontoid) resulted in ventral compression of the craniocervical junction in each of these patients. Highlighting the hypermobility that causes such lesions, following fusion, the pannus and symptoms in several patients were diminished. Impairment of normal cerebrospinal fluid circulation out of the fourth ventricle and across the craniocervical junction appears to be a plausible endpoint in this discussion and a suitable explanation for some patients with CIM. Still, the mechanisms by which cerebrospinal fluid circulation is compromised may be variable and are not well understood. This is the first study dedicated to the evaluation of pannus formation in the CIM population. We hypothesize that pharyngeal inflammatory conditions contribute to the formation and progression of hindbrain herniation in a small subset of patients with CIMs.

Upward Translation of Cerebellar Tonsils following Surgical Expansion of Supratentorial Cranial Vault: A Unified Biomechanical Explanation of Chiari Type I

Cerebellar tonsils moved significantly upward in 3 patients with Chiari type I who underwent supratentorial cranial vault expansion to alleviate intracranial pressure related to multisutural craniosynostosis. The Chiari type I deformities in these patients were the biomechanical consequence of posterior fossa-cerebellar disproportion caused by supratentorial craniocerebral disproportion secondary to multisutural craniosynostosis. The authors postulate that all cases of Chiari type I deformity share the sine qua non feature of posterior fossa-cerebellar disproportion.

Physical activity programs for promoting bone mineralization and growth in preterm infants

BACKGROUND

Lack of physical stimulation may contribute to metabolic bone disease of preterm infants, resulting in poor bone mineralization and growth. Physical activity programs combined with adequate nutrition might help to promote bone mineralization and growth.

OBJECTIVES

The primary objective was to assess whether physical activity programs in preterm infants improve bone mineralization and growth and reduce the risk of fracture.The secondary objectives included other potential benefits in terms of length of hospital stay, skeletal deformities and neurodevelopmental outcomes, and adverse events.Subgroup analysis:• Given that the smallest infants are most vulnerable for developing osteopenia (Bishop 1999), a subgroup analysis was planned for infants with birth weight < 1000 g.• Calcium and phosphorus intake may affect an infant's ability to increase bone mineral content (Kuschel 2004). Therefore, an additional subgroup analysis was planned for infants receiving different amounts of calcium and phosphorus, along with full enteral feeds as follows. ∘ Below 100 mg/60 mg calcium/phosphorus or equal to/above 100 mg/60 mg calcium/phosphorus per 100 mL milk. ∘ Supplementation of calcium without phosphorus. ∘ Supplementation of phosphorus without calcium.

SEARCH METHODS

The standard search strategy of the Cochrane Neonatal Review Group (CNRG) was used. The search included the Cochrane Central Register of Controlled Trials (CENTRAL) (2012, Issue 9), MEDLINE, EMBASE, CINAHL (1966 to March 2013), and cross-references, as well as handsearching of abstracts of the Society for Pediatric Research and the International Journal of Sports Medicine.

SELECTION CRITERIA

Randomized and quasi-randomized controlled trials comparing physical activity programs (extension and flexion, range-of-motion exercises) versus no organized physical activity programs in preterm infants.

DATA COLLECTION AND ANALYSIS

Data collection, study selection, and data analysis were performed according to the methods of the CNRG.

MAIN RESULTS

Eleven trials enrolling 324 preterm infants (gestational age 26 to 34 weeks) were included in this review. All were small (N = 16 to 50) single-center studies that evaluated daily physical activity for three and one-half to eight weeks during initial hospitalization. Methodological quality and reporting of included trials were variable.Four trials demonstrated moderate short-term benefits of physical activity for bone mineralization at completion of the physical activity program. The only trial assessing long-term effects on bone mineralization showed no effect of physical activity administered during initial hospitalization on bone mineralization at 12 months corrected age. Meta-analysis from four trials demonstrated a positive effect of physical activity on daily weight gain (weighted mean difference (WMD) 2.21 g/kg/d, 95% confidence interval (CI) 1.23 to 3.19). Data from four trials showed a positive effect on linear growth (WMD 0.12 cm/wk, 95% CI 0.01 to 0.24) but not on head growth (WMD -0.03 cm/wk, 95% CI -0.14 to 0.08) during the study period. Only one trial reported on fractures (this outcome did not occur in intervention and control groups) and complications of preterm birth (no significant differences between intervention and control groups). None of the trials assessed other outcomes relevant to this review.

AUTHORS' CONCLUSIONS

Some evidence suggests that physical activity programs might promote short-term weight gain and bone mineralization in preterm infants. Data are inadequate to allow assessment of harm or long-term effects. Current evidence does not support the routine use of physical activity programs in preterm infants. Further trials incorporating infants with a high baseline risk of osteopenia are required. These trials should address adverse events, long-term outcomes, and the effects of nutritional intake (calories, protein, calcium, phosphorus).

Associated disorders of Chiari Type I malformations: a review

A single pathophysiological mechanism of Chiari Type I malformations (CM-I) has been a topic of debate. To help better understand CM-I, the authors review disorders known to be associated with CM-I. The primary methodology found among most of them is deformation of the posterior cranial fossa, usually with subsequent decrease in volume. Other mechanisms exist as well, which can be categorized as either congenital or acquired. In understanding the relationship of such disorders with CM-I, we may gain further insight into the process by which cerebellar tonsillar herniation occurs. Some of these pathologies appear to be true associations, but many appear to be spurious.

Chiari type 1 anomaly in pseudohypoparathyroidism type Ia: pathogenetic hypothesis

AIM

This study aims to report a patient with Chiari type 1 malformation (CM1) occurring in the context of pseudohypoparathyroidism type 1a (PHP-Ia) that we believe represents the first instance of this association in the current literature.

CASE REPORT

The authors describe the case of a 6-year-old girl diagnosed with PHP-Ia who presented an associated tonsillar descent. During the follow-up, the skull vault and the occipital squama became extremely thickened at the same time as the tonsillar herniation showed a marked regression.

DISCUSSION

Chronic tonsillar descent has been reported in diverse genetic and metabolic diseases of bone. A constant finding in PH-Ia consists of changes that mainly involve the bones of the patients' hands and feet. Cerebral anomalies have also been documented in PHP-Ia, especially cerebral calcifications, but in contrast involvement of the skull bones has seldom been described in this condition. The authors briefly discuss the probable role played by the observed skull changes in the origin and subsequent regression of the tonsillar descent in this child.

CONCLUSIONS

We suggest that CM1 may develop in patients with PHP-Ia and that it should be actively sought, especially in individuals diagnosed with PHP-Ia presenting with neurological manifestations. Probably, the seeming rarity of chronic tonsillar descent in PHP-Ia is due to the fact that many patients with this condition are rarely investigated with magnetic resonance.

Chiari malformation type I: related conditions

Chiari malformation type I (CMI) is a morphological diagnosis defined as the inferior displacement of the cerebellum through the foramen magnum. In parallel to this basic definition of CMI, there are diagnoses that co-exist with CMI in selected patients. In addition, there are specific constellations of clinical symptoms and signs reported in the literature that occur non-randomly in patients affected by CMI. There is no established system that categorizes these CMI-related conditions or even defines them as causes or consequences of CMI. Identifying the relationship between CMI and these associated disorders may allow greater understanding of CMI etiology and potentially inform CMI management.

Institutional experience with 500 cases of surgically treated pediatric Chiari malformation Type I

OBJECT

The diagnosis and treatment of Chiari malformation Type I (CM-I) has evolved over the last few decades. The authors present their surgical experience of over 2 decades of treating children with this form of hindbrain herniation.

METHODS

The authors conducted a retrospective review of their institutional experience with the surgical treatment of the pediatric CM-I from 1989 to 2010.

RESULTS

The 2 most common presentations were headache/neck pain (40%) and scoliosis (18%). Common associated diagnoses included neurofibromatosis Type 1 (5%) and idiopathic growth hormone deficiency (4.2%). Spine anomalies included scoliosis (18%), retroversion of the odontoid process (24%), Klippel-Feil anomaly (3%), and atlantooccipital fusion (8%). Approximately 3% of patients had a known family member with CM-I. Hydrocephalus was present in 48 patients (9.6%). Syringomyelia was present in 285 patients (57%), and at operation, 12% of patients with syringomyelia were found to have an arachnoid veil occluding the fourth ventricular outlet. Fifteen patients (3%) have undergone reoperation for continued symptoms or persistent large syringomyelia. The most likely symptoms and signs to resolve following surgery were Valsalva-induced headache and syringomyelia. The average hospital stay and "return to school" time were 3 and 12 days, respectively. The follow-up for this group ranged from 2 months to 15 years (mean 5 years). Complications occurred in 2.4% of cases; there was no mortality. No patient required acute return to the operating room, and no blood transfusions were performed.

CONCLUSIONS

The authors believe this to be the largest reported series of surgically treated pediatric CM-I patients and hope that their experience will be of use to others who treat this surgical entity.

Chiari type I malformation in children

The diagnosis of Chiari type I malformation (CIM) is more and more frequent in clinical practice due to the wide diffusion of magnetic resonance imaging. In many cases, such a diagnosis is made incidentally in asymptomatic patients, as including children investigated for different reasons such as mental development delay or sequelae of brain injury. The large number of affected patients, the presence of asymptomatic subjects, the uncertainties surrounding the pathogenesis of the malformation, and the different options for its surgical treatment make the management of CIM particularly controversial.This paper reports on the state of the art and the recent achievements about CIM aiming at providing further information especially on the pathogenesis, the natural history, and the management of the malformation, which are the most controversial aspects. A historial review introduces and explains the current classification. Furthermore, the main clinical, radiological, and neurophysiological findings of CIM are described to complete the picture of this heterogeneous and complex disease.

The incidence of Chiari malformation in nonsyndromic, single suture craniosynostosis

INTRODUCTION

This study was designed to determine the incidence of Chiari malformation (CM) in nonsyndromic single suture craniosynostosis (N-SSSC).

MATERIALS AND METHODS

A retrospective analysis of brain magnetic resonance imaging (MRI) studies of children undergoing craniofacial surgery during 1 January, 2004-31 March, 2009 in Cleft Palate and Craniofacial Centre, Department of Plastic Surgery, Helsinki University Hospital, Helsinki, Finland, was conducted.

RESULTS AND DISCUSSION

One hundred twenty-four N-SSSC patients were imaged using brain MRI. Of these 124 patients, seven patients were diagnosed with N-SSSC with an associated CM; the incidence CM in association with N-SSSC was thus 5.6%. The average age at the time of MRI was 37.7 months. All were males, except one. Only two types of synostosis were identified in this patient cohort: synostosis involving the sagittal suture in five cases and right coronal synostosis in two cases. The CM malformations were relatively large. The tonsillar herniation varied from 6 to 12 mm (median 9 mm). All these patients were asymptomatic of their CMs. None had operation designed directly to correct the CM.

CONCLUSION

As a conclusion, we state that the association of CM and N-SSSC is a relatively common finding, with an incidence of 5.6% in preoperative brain MRI. The significance of finding CM in preoperative brain MRI should be assessed individually in asymptomatic patients.

Incidence of basioccipital hypoplasia in Chiari malformation type I: comparative morphometric study of the posterior cranial fossa. Clinical article

OBJECT

The chronic tonsillar herniation defining Chiari malformation Type I (CMI) is thought to result from overcrowding of a normally developing hindbrain within a congenitally small posterior cranial fossa (PCF) due to occipital hypoplasia. The goals in the present study were to authenticate the cranioencephalic disproportion in a group of patients with CMI and to discuss new developmental aspects according to which part of the occipital bone was underdeveloped.

METHODS

The authors retrospectively examined a group of 17 patients with CMI. Measurements of osteotentorial and neural structures of the PCF were made on MR images of the brain. The results were compared with findings in 30 healthy controls by using the Mann-Whitney U-test.

RESULTS

Dimensions of the neural structures did not differ between the 2 groups of patients. The mean length of the basiocciput was significantly shorter in the CMI group (19.4 mm) compared with the control group (25.7 mm; p = 0.0003). The mean diameter of the foramen magnum was larger in the CMI group, but this difference was not statistically significant. The dimensions of the supraocciput and the mean angle of the cerebellar tentorium were identical in the 2 groups.

CONCLUSIONS

Data in this study support the idea that occipital hypoplasia is the main cause of overcrowding within the PCF. Basioccipital shortness is a cardinal feature of the resultant shallow PCF and could proceed from a congenital disorder of the cephalic mesoderm of the parachordal plate or occur later in the infancy because of premature stenosis of the sphenooccipital synchondrosis.

Chiari I malformation after cranial radiation therapy in childhood: a dynamic process associated with changes in clival growth

OBJECT

The small posterior fossa is believed to be relevant to the development of Chiari I malformation (CMI). In this study, we evaluated children with supratentorial tumors developing CMI after radiation therapy (RT) that involved the skull base. Changes in clivus and supraocciput growth rate were correlated with tonsillar herniation.

METHODS

Ten children who underwent RT for supratentorial tumors at St. Jude Children's Research Hospital (1994-2008) developed CMI on follow-up magnetic resonance imaging (MRI). Four other patients with supratentorial tumor and CMI who did not receive RT were identified. Length of the supraocciput, basisphenoid, and basichondrium and extent of tonsillar herniation were measured on serial midsagittal MRI.

RESULTS

Over the median follow-up of 85.5 months, basisphenoid annual growth rate was significantly lower in children receiving RT for suprasellar tumor (n=8) than those who did not (p=0.04). Growth of clivus and basisphenoid was significantly lower in the first 12 months after RT in children who received RT for suprasellar tumor (p=0.03 and p=0.04, respectively). In these patients, tonsillar herniation increased over 24 months after RT, reaching maximal descent at a mean of 20.2 months; this resolved as clival growth returned to normal. No patient was symptomatic.

CONCLUSIONS

In these children, restriction of clival growth occurred after RT for suprasellar tumors. Changes in clival growth were associated with changes in the extent of tonsillar herniation. This supports the importance of the small posterior fossa and reduced clival length in the etiology of CMI.

Delamination technique together with longitudinal incisions for treatment of Chiari I/syringomyelia complex: a prospective clinical study

Background

Treatment modalities in Chiari malformation type 1(CMI) accompanied by syringomyelia have not yet been standardized. Pathologies such as a small posterior fossa and thickened dura mater have been discussed previously. Various techniques have been explored to enlarge the foramen magnum and to expand the dura. The aim of this clinical study was to explore a new technique of excision of the external dura accompanied by widening the cisterna magna and making longitudinal incisions in the internal dura, without disturbing the arachnoid.

Methods

Ten patients with CMI and syringomyelia, operated between 2004 and 2006, formed this prospective series. All cases underwent foramen magnum decompression of 3 × 3 cm area with C1–C2 (partial) laminectomy, resection of foramen magnum fibrous band, excision of external dura, delamination and widening of internal dura with longitudinal incisions.

Results

Patients were aged between 25 and 58 years and occipital headache was the most common complaint. The mean duration of preoperative symptoms was 4 years and the follow-up time was 25 months. Clinical progression was halted for all patients; eight patients completely recovered and two reported no change. In one patient, there was a transient cerebrospinal fluid (CSF) fistula that was treated with tissue adhesive. While syringomyelia persisted radiologically with radiological stability in five patients; for three patients the syringomyelic cavity decreased in size, and for the remaining two it regressed completely.

Conclusion

Removal of the fibrous band and the outer dural layer, at level of foramen magnum, together with the incision of inner dural layer appears to be good technique in adult CMI patients. The advantages are short operation time, no need for duraplasty, sufficient posterior fossa decompression, absence of CSF fistulas as a result of extra arachnoidal surgery, and short duration of hospitalization. Hence this surgical technique has advantages compared to other techniques.

Morphometric analysis of the craniocervical juncture in children with Chiari I malformation and concomitant syringobulbia

INTRODUCTION

Although very uncommon, Chiari I malformation (CIM) with syringomyelia may be associated with concomitant syringobulbia. We hypothesized that the anatomy of the craniocervical region may be different in CIM patients with syringomyelia who develop syringobulbia in conjunction with their syringomyelia compared to other patients with CIM with and without syringomyelia. The present study was conducted in order to prove or disprove such a theory.

MATERIALS AND METHODS

A group of 189 children with operated CIM were reviewed for the presence of syringobulbia, and this cohort then underwent morphometric analyses of their craniocervical juncture. These measurements were then compared to both our prior patient findings and historic controls.

RESULTS

The current study did not identify any morphometrical peculiarities for patients with CIM and syringobulbia compared to other CIM patients with and without isolated syringomyelia.

CONCLUSIONS

Based on our study, the mechanism behind such cerebrospinal fluid distention into the brain stem remains elusive with no single morphometrical difference in patients with CIM and syringobulbia compared to other patients with CIM. Perhaps, future testing aimed at identifying pressure gradients across the foramen magnum in patients with and without syringobulbia and concomitant CIM may be useful.

Effects of motor physical therapy on bone mineralization in premature infants: a randomized controlled study

OBJECTIVE

To study the effect of physical therapy on bone mineralization, weight gain and growth in preterm infants.

METHOD

After fulfilling the inclusion criteria, preterm infants were matched for gestational age and birth weight and then randomly assigned to the physiotherapy group (PG, n=15) and control group (CG, n=14). The PG received motor physical therapy for 15 min daily, 5 times per week until hospital discharge. Bone mineralization was measured by total body dual energy X-ray beam absorptiometry (DEXA) at the onset and end of the study. Statistical analysis was realized by ANCOVA and linear correlation tests.

RESULT

The physical therapy group (PG) presented greater body weight gain per day (27.4+/-2.4 vs 21.01+/-4.4 g, P<0.001) and length (1.3+/-0.3 vs 0.8+/-0.2 cm week(-1), P<0.001) than did the control group (CG). Body composition values verified by DEXA were greater for the PG. The mean gain in bone mineral content (BMC) (mg) was greater in the PG (434+/-247.5 vs -8.9+/-11.4, P<0.001), as was the mean bone mineral density (BMD) gain (mg cm(-2)) (8.4+/-5.6 vs -3.1+/-5.5, P<0.001). The gain in bone area (BA,cm(2)) was 10.3+/-5 in the PG vs 1.5 +/-2 in the CG (P<0.001). The gain in lean mass (LM) (g) in the PG was also greater than in the CG (271.1+/-21.4 vs 109.1+/-1.0, P<0.009). The fat mass (g) was similar between the groups (P=0.432).

CONCLUSION

These results showed that physiotherapy in preterm infants produced greater gains in growth, body weight, BMC, BMD, BA and LM.

Volumetric analysis of the posterior cranial fossa in a family with four generations of the Chiari malformation Type I

OBJECT

Many authors have concluded that the Chiari malformation Type I (CM-I) is due to a smaller than normal posterior cranial fossa. In order to establish this smaller geometry as the cause of hindbrain herniation in a family, the authors of this paper performed volumetric analysis in a family found to have this malformation documented in 4 generations.

METHODS

Members from this family found to have a CM-I by imaging underwent volumetric analysis of their posterior cranial fossa using the Cavalieri method.

RESULTS

No member of this family found to have CM-I on preoperative imaging had a posterior fossa that was significantly smaller than that of age-matched controls.

CONCLUSIONS

The results of this study demonstrate that not all patients with a CM-I will have a reduced posterior cranial fossa volume. Although the mechanism for the development of hindbrain herniation in this cohort is unknown, this manifestation can be seen in multiple generations of a familial aggregation with normal posterior fossa capacity.

The pediatric Chiari I malformation: a review

BACKGROUND

Both the diagnosis and treatment regimens for the Chiari I malformation (CIM) are varied and controversial. The present paper analyzes the literature regarding this form of hindbrain herniation in regard to definition, anatomy, pathobiology, symptoms, findings, treatment, and outcomes.

DISCUSSIONS

Appropriate literature germane to the CIM is reviewed and discussed. There is variation in the reported anatomy, outcome, and treatment for children with CIM. Based on the literature, most patients have preoperative symptoms or findings (e.g., syringomyelia) improve no matter what surgical technique is utilized. However, standardized treatment paradigms based on randomized controlled studies are still necessary to elucidate the optimal selection and treatment criteria.

Physical activity programs for promoting bone mineralization and growth in preterm infants

BACKGROUND

Lack of physical stimulation may contribute to metabolic bone disease of preterm infants resulting in poor bone mineralization and growth. Physical activity programs in the presence of adequate nutrition might help to promote bone mineralization and growth.

OBJECTIVES

The primary objective of this review was to assess whether physical activity programs in preterm infants improve bone mineralization and growth and reduce the risk of fractures.

SEARCH STRATEGY

Following the standard search strategy of the Cochrane Neonatal Review Group, a search was conducted in September 2006 including PubMed, EMBASE, CINAHL, the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 3, 2006), cross-references and handsearching of abstracts of the Society for Pediatric Research and the International Journal of Sports Medicine. No language restrictions were applied.

SELECTION CRITERIA

Randomized and quasi-randomized controlled trials comparing physical activity programs (extension and flexion, range-of-motion exercises for several minutes a day several days per week for at least two weeks) to no organized physical activity programs in preterm infants. Eligible studies included those that provided physical activity for the experimental group, with or without massage and/or tactile stimulation for both experimental and control groups, as well as information on at least one outcome of interest.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed searches and extracted data. All three review authors were involved in selection and assessment of quality of studies. The statistical methods included relative risk (RR), risk difference (RD) and number needed to treat (NNT) for dichotomous outcomes and weighted mean difference (WMD) for continuous outcomes, reported with 95% confidence intervals (CI). Heterogeneity was estimated by the I(2) statistic. A fixed effect model was used to pool data for meta-analyses.

MAIN RESULTS

Six trials enrolling 169 preterm infants (gestational age 26 to 34 weeks) were included in this review. All were small (N = 20 - 49) single center studies evaluating daily physical activity for 3.5 to 4 weeks during initial hospitalization. The methodological quality and reporting of all trials was poor. None of them stated the methods of concealment of patient allocation, the method of randomization or attempted blinding of the intervention. Only two trials attempted blinding of outcome assessors for outcomes relevant to this review. Two trials (N = 55) demonstrated moderate short-term benefits of physical activity on bone mineralization at completion of the physical activity program. Data was not pooled for meta-analyses due to methodological differences. The only trial (N = 20) assessing long-term effects on bone mineralization showed no effect of physical activity administered during initial hospitalization on bone mineralization at 12 months corrected age. Meta-analysis from three trials (N = 78) demonstrated an effect of physical activity on daily weight gain (WMD 2.77 g/kg/d, 95% CI 1.62, 3.92). Data from two trials (N = 58) showed no effect on linear growth (WMD -0.04 cm/week, 95% CI -0.19, 0.11) or head growth (WMD -0.03 cm/week, 95% CI -0.14, 0.09) during the study period. The I(2) statistic suggested heterogeneity on the analysis of linear growth (p = 0.006, I(2) = 86.9%). None of the trials assessed fractures or other outcomes relevant to this review. Data was insufficient for subgroup analyses based on birth weight and calcium/phosphorus intake.

AUTHORS' CONCLUSIONS

There is weak evidence from six small randomized trials of poor methodological and reporting quality that physical activity programs might promote moderate short-term weight gain and bone mineralization in preterm infants. The clinical importance of these findings is questionable given the small effect size and low baseline risk of poor bone mineralization and growth in study participants. Data is inadequate to assess harm or long term effects. Current evidence does not justify the standard use of physical activity programs in preterm infants. Further evaluation of this intervention in well designed trials incorporating extremely low birth weight infants who are at high risk of osteopenia is required. Future trials should report on adverse events and long term outcomes including fractures, growth, bone mineralization, skeletal deformities and neurodevelopmental impairment. These trials should address the possibility that nutritional intake (calories, protein, calcium, phosphorus) might modify the effects of physical activity.

Two- and three dimensional measures of vestibular schwannomas and posterior fossa--implications for the treatment

BACKGROUND

There is no uniformly accepted method of reporting the size of vestibular schwannomas (VS) and to evaluate the individual tumour behaviour in the posterior fossa (PF). To help the treatment decision we investigated the VS and PF morphometry using a computerized method.

METHOD

Stereotactic fused CISS MR and CT scan images were obtained from 58 adult patients (31 males and 27 females) harbouring an unilateral VS (25 Koos II, 21 Koos III and 12 Koos IV). Using a Gammaplanworking station we screened for the following measures: anteroposterior (AP), craniocaudal (CC), transverse (T) and maximum (Max) diameters (Diam) of the intracisternal part of the tumour, VS and PF volumes.

FINDINGS

The Max Diam was the most accurate way to estimate the tumour volume (Spearman's rho >0.80). Among several parameters, the T Diam was the best measure to assess the brain shift (ROC analysis) with a cut off value at 14.5 mm (91.7% sensitivity and 93% specificity). VS volume and the ratio VS volume/PF volume were also efficient to predict a brain shift.

CONCLUSIONS

Max Diam and T Diam are bedside measured simple data of particular interest to respectively estimate the VS volume and predict the brain shift due to the tumour. The determination of cut-off values correlated to brain shift will provide guidelines at the time of the therapeutic decision between radiosurgical and microsurgical strategy.

Pentasomy 49,XXXXY associated with a Chiari type 1 malformation and cervical syrinx

Pentasomy 49,XXXXY occurs in 1/85,000 newborn males. The origin of this particular form of aneuploidy is believed to be a result of consecutive nondisjunction events during maternal meiosis. Typical presentation consists of hypotonia, developmental delay, various dysmorphic features, and severe hypogenitalism. A 13-year-old with pentasomy 49,XXXXY and a Chiari type 1 malformation with an associated cervical syrinx is presented.