Precocious, early and fast puberty in males with Chiari I malformation

Type I Chiari malformation is a disorder characterized by a displacement of the cerebellar tonsils through the foramen magnum into the upper cervical spinal canal and, contrary to type II Arnold-Chiari malformation, without the presence of myelomeningocele. As described in the literature, patients suffering from Arnold-Chiari malformation with myelomeningocele can frequently present with precocious puberty, whereas only one report shows an association between Chiari I malformation and early puberty. We describe three young males--8.8, 9.4 and 10.4 years old--who were diagnosed with precocious, early and fast puberty associated with type I Chiari malformation. In patients 2 and 3, the reason for diagnostic management recommendation was a rapid progression of pubertal development over one year. None of the patients manifested hypophyseal-hypothalamic axis dysfunction other than sexual precocity. Neurological and ophthalmological examinations were normal in all patients. Our data show that type I Chiari malformation can be considered one of the possible causes for precocious, early and accelerated puberty in male patients, suggesting the need to carry out brain nuclear magnetic resonance imaging in order to investigate the presence of this malformation.     

Preliminary observations on the association between simple metopic ridging in children without trigonocephaly and the Chiari I malformation

Historically, there have been no accounts of an association between simple metopic ridging and the Chiari I malformation. We prospectively evaluated 50 children with simple metopic ridges and found that 30% of these patients had a Chiari I malformation. During the period in which this screening for simple metopic ridges was performed, only 9% of the total patient population (324) was diagnosed as having a Chiari I malformation. We hypothesize that small decreases in anterior fossa volume in children with a simple metopic ridge and no other clinical findings of trigonocephaly may increase their chance of having a Chiari I malformation that becomes symptomatic. In addition, simple metopic ridging should perhaps be added to the list of bony anomalies associated with the Chiari I malformation, such as atlantal assimilation and retroverted odontoid processes. Future studies aimed at calculating anterior fossa volumes in children with a Chiari I malformation and imaging all children with simple metopic ridges are now necessary to ascertain if there is an increased risk of these patients becoming symptomatic with a hindbrain hernia or having a hindbrain hernia, respectively.     

Chiari malformation type III treated with primary closure

Chiari malformations represent various clinical and anatomic processes that entail varying degrees of involvement of the rhombencephalon (hindbrain). The type III Chiari malformation is distinctly rare. Chiari described only one case of his type III deformity, which is indicative of its rarity. We report a case of Chiari malformation type III, a female child who presented to us at the age of 1 month with a swelling at the back of the neck since birth. MRI revealed a Chiari type III malformation with a high cervical meningoencephalocele along with herniation of cerebellar tissue through the bony defect in the posterior elements of the C2 vertebra. At surgery, the meningoencephalocele was excised along with the gliotic cerebellar tissue, and a posterior fossa decompression along with augmentation duraplasty was done. The postoperative period was uneventful. The case and relevant literature is reviewed.     

The position of the conus medullaris in children with a Chiari I malformation

The purpose of this study is to determine whether there is a relationship between the conus level and patients with a Chiari I malformation. This retrospective MRI study evaluated conus levels and degrees of tonsillar ectopia in 26 children ages 5-16 years with a Chiari I malformation. Our results show that there seems to be no relationship between the conus level and the amount of tonsillar ectopia that a child with a Chiari I malformation might have. In fact, there seemed to be an inverse relationship between these two entities. Interestingly, we have also found that of all coni located at the L2-L3 disc space or below, these patients had a syrinx associated with their Chiari I malformation and that all malformations without a syrinx had a 'normally' positioned conus medullaris.     

Reoperation for Chiari malformations

BACKGROUND: We undertook this study to characterize those patients who required reoperations for Chiari malformation and to determine whether modifications in surgical technique at the initial procedure might have obviated the need for repeat surgery. METHODS: We reviewed the hospital records, imaging studies, operative reports, and follow-up data of those patients who were undergoing a second operation as part of a consecutive series of Chiari decompressions carried out by one neurosurgeon over a 14-year period. We wished to determine whether type of Chiari malformation, age at initial surgery, the presence of associated bony anomalies, or initial operative technique contributed to the need for reoperation. RESULTS: Twenty-two (17%) of the surgical procedures represented reoperations (16 of 100 Chiari I and 6 of 33 Chiari II decompressions). Of the patients in the series who were operated on at age 5 years or younger, 7 (16%) were reoperations (5 of 33 Chiari I and 2 of 10 Chiari II decompressions); 15 patients (17%) of those older than 5 years at surgery were reoperations (11 of 67 Chiari I and 4 of 23 Chiari II decompressions). 8 of the 16 patients who underwent reoperations for Chiari I malformation and 4 of the 6 patients who underwent reoperations for Chiari II malformation had their initial decompression surgery at age 5 years or younger. Reoperation was required because of failure to treat adequately an associated syrinx (n=11), because of persisting neurological symptoms or headache (n=9), or because of a possible faulty fourth ventricular stent placement (n=2). 5 of 9 patients in the operative series with Chiari malformations associated with craniosynostosis represented reoperations (55%), and all 3 of the patients whose syrinx persisted after reoperation had craniosynostosis syndromes. CONCLUSIONS: Approximately 17% of the patients with Chiari I and Chiari II malformations in this operative series were undergoing a second operation. Factors in this series which were associated with reoperation included a young age at initial surgery, the presence of complex bony anatomy at the foramen magnum, syndromic craniosynostosis, and failure of the surgeon at the initial operation either to assess patency of the foramen of Magendie or correctly place a fourth ventricular stent.     

Chiari type I malformation causing central apnoeas in a 4-month-old boy

Apnoea is a rare but well-known clinical presentation of the Chiari type I malformation. It may be either obstructive or central in nature, and has been described in children, adolescents and adults. Here, we report a 4-month-old infant who presented with frequent central sleep apnoeas leading to the diagnosis of a Chiari type I malformation. Surgical repair resulted in complete resolution of the symptoms, normal respiratory parameters during sleep and normal psychomotor development.This case illustrates a very early presentation of the Chiari type I malformation with central apnoeas and suggests that this aetiology should be considered in the differential diagnosis of central apnoeas in infants, especially when they are associated with other neurological sign or symptom.     

Chiari II malformation and occult spinal dysraphism. Case reports and a review of the literature

We report two cases of children with occult spinal dysraphism who were also found to have many associated brain anomalies seen in the Chiari II malformation. No previous report has commented on the possible association between the Chiari II malformation and the 'closed' form of neural tube defect. One child had symptoms referable to pathology at the craniocervical junction. Neither child had cutaneous stigmata associated with occult spinal dysraphism over the caudal midline spine. These cases, although seemingly rare, lend support to the theories that the association between the Chiari II malformation and patients with myelomeningoceles is due to dysgenesis of the rostral and caudal neural tube. These cases are also important as refutation of earlier theories that link these two entities by proposing that the Chiari II malformation is due to overdrainage of cerebrospinal fluid at the site of myelomeningocele.     

Toward a simpler surgical management of Chiari I malformation in a pediatric population.

A wide variety of surgical adjuvants to the standard bony decompression have been advocated in the treatment of the Chiari I malformation, especially when the tonsillar herniation is associated with hydrosyringomyelia. These include various shunting procedures, duroplasty, obex plugging, and resection of the cerebellar tonsils. Our practice has been to avoid these adjuvants and to perform a simple limited occipital craniectomy, C1 laminectomy, and dural opening. The dura mater is left open and overlain with oxidized cellulose. To evaluate the efficacy of this more limited procedure, a retrospective review was performed of the medical records of 31 consecutive patients treated over a 6-year period. Twenty-six (84%) of these patients had an associated spinal cord syrinx; all underwent the same procedure. The follow-up period ranged from 15 to 93 months, with all patients having at least one postoperative magnetic resonance imaging at 6 months. Twenty-three of the 26 patients (88%) who presented with a syrinx had significant resolution of the syrinx on follow-up scans with concomitant improvement of presenting signs and symptoms. Of the remaining 3 patients, 1 had progressive hydrocephalus and received a ventriculoperitoneal shunt, with symptom resolution. In the other 2 patients the syrinx did not diminish; both received syringopleural shunts. Postoperative morbidity includes a 26% incidence of headaches, of which half resolved within 5 days, and only 1 persisted beyond 2 weeks. Nausea and vomiting occurred in 16%. Neither of these figures significantly exceeds those of other large surgical series in which the dura mater was closed with a patch graft. Three patients (10%) did have a postoperative cerebrospinal fluid leak; all responded to bedside suturing without further sequelae. This study indicates that a simple bone removal and open dural decompression of the cervicomedullary junction is a safe, effective operative treatment for Chiari I malformation in children. Shunts, duroplasty, obex plugging, and tonsillar resection offer no benefit regarding the outcome when our series is compared to others in which such adjuvants were used.     

Chiari type I malformation in children

We reviewed the recent experience at Texas Children's Hospital by examining the records of 11 children who underwent suboccipital decompression for symptomatic Chiari type I malformation. Presenting complaints included neck pain (1 child), scoliosis (4 children), back pain (1 child), torticollis (1), motor dysfunction (1), and apnea (3 children). Neurologic findings were normal in 7 of the 11 children. The craniocervical junction and medulla were studied by magnetic resonance imaging, which revealed anatomy consistent with Chiari type I malformation in all cases. At surgery, all patients had tonsillar herniation to the first cervical vertebra or below. Three patients had syringomyelia. Postoperatively, either the patients were symptom free or, in the cases of scoliosis and torticollis, there was no progression. Our experience suggests that Chiari type I malformation may occur in childhood with varied and unusual clinical findings. Magnetic resonance imaging was essential to the diagnosis; the presence of tonsillar herniation was confirmed at surgery. The results of suboccipital decompression were favorable in this series.     

Complete spontaneous resolution of childhood Chiari I malformation and associated syringomyelia

The diagnosis of Chiari I malformation and associated syringomyelia is often made in childhood. Since the advent of magnetic resonance imaging, these abnormalities are increasingly detected incidentally. Despite incomplete understanding of the natural history of asymptomatic Chiari I malformations, the current recommendation is to consider prophylactic surgical intervention in those with an associated syringomyelia. This case report presents a complete spontaneous resolution of a Chiari I malformation and syringomyelia in a child. It illustrates the possibility that asymptomatic children with Chiari I malformations and syringomyelia may be followed conservatively.     

Recurrence of symptoms after Chiari decompression and duraplasty with nonautologous graft material

Nonautologous material is commonly used for dural grafting. Although good results have been reported with the use of some of these materials in cranial surgery, there is a paucity of information regarding their use in craniocervical decompressive surgery. We report three cases of patients with Chiari malformation type I who experienced recurrent or new-onset Chiari symptoms after surgical decompression and duraplasty with bovine pericardium, Gore-Tex or cadaveric dura. We review the use of these materials and propose possible mechanisms by which a reaction to a nonautologous graft could cause recurrent Chiari symptoms. The preferential use of autologous material for dural grafts during posterior fossa decompressive surgery should prevent this cause of symptom recurrence.     

Chiari I malformations and hydromyelia--complications.

The Chiari I malformation is associated with a hydromyelic cavity in 55-75% of patients. In the author's series (1977-1991), hydromelia occurred in 111 of 131 patients (85%). There were 35 children. Posterior fossa decompression with duraplasty and fourth ventricle to subarachnoid shunt was made in all patients with Chiari I malformation with hydromyelia. The obex connection to the cervical cord central canal was closed with muscle, if widely patent. Eighty-five percent showed sustained objective improvement. The precautions taken to avoid complications and a literature review are tabulated for easy reference.     

The Chiari II malformation: lesions discovered within the fourth ventricle.

Structural lesions associated with the Chiari II malformation have been identified within the fourth ventricle in 8 patients. During the 42-month period encompassing the operations of the 7 patients treated surgically, only 9 other patients were explored without the discovery of some associated structural lesion. The patients ranged in age from 2 to 26 years. The following lesions were identified: glial or arachnoidal cysts (3 patients), glial or choroidal nodules (3 patients) and subependymoma (2 patients). These lesions were all situated in the roof of the fourth ventricle adjacent to or interspersed with the choroid plexus. Only the cystic lesions were identified by preoperative imaging. In only 1 case did the associated lesion, a 2-cm cyst, seem to contribute to the patient's clinical presentation. Structural lesions of the fourth ventricle associated with the Chiari II malformation are common in patients who are submitted to decompression. These lesions may be dysplasias of developmental origin, or they may be reactive lesions related to chronic compression and ischemia. They do not necessarily required biopsy or excision.     

Prepontine lesions with chiari II malformation. Report of two cases

In 2 cases of infants with the Chiari II malformation, a prepontine cyst presented in association with the hindbrain abnormalities characteristic of the Chiari II syndrome. Both infants presented with bulbar dysfunction and had poor outcome despite decompression of the cerebellar tonsillar herniation and drainage of the prepontine cysts. No such association between prepontine lesions and Chiari II has been described previously.     

Chiari type I malformation in children: presentation in 34 cases]

Incidental diagnoses of Chiari I malformation are more and more frequent in pauci or asymptomatic children. The value of neurophysiological investigations for surgical indications is discussed. OBJECTIVE: To determine clinical presentations of Chiari I malformation and relative frequencies of severe and incidental forms, and to evaluate the usefulness of neurophysiological investigations for surgical indications. METHODS: This retrospective study included 34 patients admitted from 1984 to 2000, with Chiari I malformation diagnosis in different pediatric (intensive care, neurology and neurosurgery) units of a university hospital. RESULTS: The clinical presentation was severe (two children died) in four cases (12%). Signs of brain stem compression were found in 41% of cases, scoliosis in 21%, and incidental diagnosis in 26%. The polysomnography, performed in 12 cases, showed sleep-apneas in six cases. One child with an incidental diagnosis of Chiari I malformation had many sleep-apneas which required a surgical treatment. A surgical decompression was performed in 69% of cases, with clinical improvement in 77%. CONCLUSION: The high incidence (12%) of severe forms revealing Chiari I malformations justifies systematic neurophysiological investigations for the initial evaluation and the follow-up of Chiari 1 malformations, including the less symptomatic forms.     

Konnataler Stridor, muskul?re Hypotonie und Hydrocephalus occlusus

The case of a male infant with congenital stridor, retardation of motor function due to muscular hypotonia and development of hydrocephalus is presented. MR imaging revealed a Chiari type I malformation. The hydrocephalus was successfully treated by endoscopic third ventriculostomy. The case illustrates the occasionally complex symptomatology and diagnostic challenges of Chiari type I malformation.     

Spontaneous resolution of Chiari malformation Type I in monozygotic twins

The spontaneous resolution of isolated tonsillar ectopia in Chiari malformation Type I (CM-I) is a known and reported entity in 2 previous single study case reports. However, it has not been previously described in monozygotic twins. Two children, approximately 1 year of age with CM-I and presumed episodes of pallid syncope or breath-holding spells presented for neurosurgical evaluation. Although Chiari decompression was considered, the authors decided to proceed with conservative management with close follow-up due to the uncertain nature of these episodes. Approximately 4 years later, both children's symptoms had resolved. Repeated MR imaging examinations also showed spontaneous resolution of the malformation in both girls. These cases emphasize that when patients with CM-I present with atypical symptoms, spontaneous resolution or improvement is possible, which may influence the decision to pursue a trial of nonsurgical management. The possible pathophysiological mechanisms and genetic influences of CM-I are also briefly discussed.     

Development of symptomatic Chiari malformation in a child with craniofacial dysmorphism

We present the case of a 28-month-old child with craniofacial anomalies who presented for evaluation of apnea. The patient had associated symptoms referable to a Chiari malformation and MRI scanning of the head and cervical spine revealed some, but not all, of the anatomical features classically associated with the Chiari II malformation. The child has mid-face hypoplasia and it appeared that his posterior fossa hypertension was partially caused by anterior compression of the brain stem as a result of the malformation at the base of the skull. The patient responded dramatically to posterior fossa decompression. Evidence from this and other cases from the literature suggests that different pathophysiological mechanisms may cause the classic Chiari malformation and/or other anatomical abnormalities in the continuum between Chiari I and II.     

Magnetic resonance imaging features of complex Chiari malformation variant of Chiari 1 malformation

Background

Complex Chiari malformation is a subgroup of Chiari 1 malformation with distinct imaging features. Children with complex Chiari malformation are reported to have a more severe clinical phenotype and sometimes require more extensive surgical treatment than those with uncomplicated Chiari 1 malformation.

Objective

We describe reported MR imaging features of complex Chiari malformation and evaluate the utility of craniometric parameters and qualitative anatomical observations for distinguishing complex Chiari malformation from uncomplicated Chiari 1 malformation.

Materials and methods

We conducted a retrospective search of the institutional imaging database using the keywords “Chiari” and “Chiari 1” to identify children imaged during the 2006–2011 time period. Children with Chiari 2 malformation were excluded after imaging review. We used the first available diagnostic brain or cervical spine MR study for data measurement. Standard measurements and observations were made of obex level (mm), cerebellar tonsillar descent (mm), perpendicular distance to basion-C2 line (pB-C2, mm), craniocervical angle (degrees), clivus length, and presence or absence of syringohydromyelia, basilar invagination and congenital craniovertebral junction osseous anomalies. After imaging review, we accessed the institutional health care clinical database to determine whether each subject clinically met criteria for Chiari 1 malformation or complex Chiari malformation.

Results

Obex level and craniocervical angle measurements showed statistically significant differences between the populations with complex Chiari malformation and uncomplicated Chiari 1 malformation. Cerebellar tonsillar descent and perpendicular distance to basion-C2 line measurements trended toward but did not meet statistical significance. Odontoid retroflexion, craniovertebral junction osseous anomalies, and syringohydromyelia were all observed proportionally more often in children with complex Chiari malformation than in those with Chiari 1 malformation.

Conclusion

Characteristic imaging features of complex Chiari malformation, especially obex level, permit its distinction from the more common uncomplicated Chiari 1 malformation.     

Regional Ependymal Upregulation of Vimentin in Chiari II Malformation,Aqueductal Stenosis,and Hydromyelia

Vimentin, glial fibrillary acidic protein (GFAP) and S-100 protein were studied by immunocytochemistry in the ependyma of patients with Chiari II malformations, congenital aqueductal stenosis, and hydromyelia. Paraffin sections of brains and spinal cords of 16 patients were examined, 14 with Chiari II malformations, most with aqueductal stenosis and/or hydromyelia as associated features, and 2 patients with congenital aqueductal stenosis without Chiari malformation. Patients ranged in age from 20-wk gestation to 48 years. The results demonstrated: 1) in the fetus and young infant with Chiari II malformations, congenital aqueductal stenosis, and hydromyelia, vimentin is focally upregulated in the ependyma only in areas of dysgenesis and not in the ependyma throughout the ventricular system; 2) GFAP and S-100 protein are not coexpressed, indicating that the selective upregulation of vimentin is not simple maturational delay; 3) vimentin upregulation also is seen in the ependymal remnants of the congenital atretic cerebral aqueduct, not associated with Chiari malformation; 4) in the older child and adult with Chiari II malformation, vimentin overexpression in the ependyma becomes more generalized in the lateral ventricles as well, hence evolves into a nonspecific upregulation. The interpretation from these findings leads to speculation that it is unlikely that ependymal vimentin is directly involved in the pathogenesis of Chiari II malformation, but may reflect a secondary upregulation due to defective expression of another gene. This gene may be one of rhombomeric segmentation that also plays a role in defective programming of the paraxial mesoderm for the basioccipital and supraoccipital bones resulting in a small posterior fossa. This interpretation supports the hypothesis of a molecular genetic defect, rather than a mechanical cause, as the etiology of the Chiari II malformation.