Symptomatic Chiari Research Articles

Scoliosis in children with Chiari I-related syringomyelia

To study the relationship between scoliosis and Chiari I malformation, with reference to the possible role of cranio-vertebral decompression in preventing the need for scoliosis correction. Out of a total of 36 patients with symptomatic Chiari I, who underwent primary cranio-vertebral decompression by a single paediatric neurosurgeon with an interest in Chiari malformation between 1998 and 2003, 13 had clinically detected scoliosis. Of these, ten had no other structural spine abnormality, which could influence the natural history of scoliosis and were included in this study. In all but one patient, syringomyelia improved significantly after cranio-vertebral decompression. Of the ten patients, eight had levoscoliosis (left convexity), all single curves, and two had curves to the right (both double curves). Six patients did not require corrective scoliosis surgery after cranio-vertebral decompression. The mean Cobb angle for those not requiring scoliosis correction was 29 degrees in contrast to a mean of 76 degrees for those requiring correction [p=0.001, one-way analysis of variance (ANOVA)]. The mean age of patients requiring corrective surgery was 158 months against 125 months for those not requiring correction (p=0.084, one-way ANOVA). These findings were confirmed by multivariate analysis, which also confirmed that symptom duration, syrinx length and site were not significant in predicting the need for corrective surgery following cranio-vertebral decompression. Cranio-vertebral decompression for Chiari I may prevent the need for corrective scoliosis surgery when performed before the age of ten and below a Cobb angle of 30 degrees.

The adult phenotype in Costello syndrome

We report clinical findings in 17 adults with Costello syndrome ranging in age from 16 to 40 years. Two patients in this series have had bladder carcinoma, the only malignancy reported to affect adults with Costello syndrome. Benign tumors included multiple ductal papillomata in two women, and a fourth ventricle mass in one man, thought to be a choroid plexus papilloma. Endocrine problems in this series were osteoporosis, central hypogonadism, and delayed puberty. Other health problems were symptomatic Chiari malformations in three patients. Four patients had adult-onset gastro-esophageal reflux, three of whom had Chiari malformations. Fourteen adults had mild to moderate intellectual disability with three individuals having severe intellectual disability; 15 individuals attained some reading and writing skills and 14 showed ongoing acquisition of new skills into adulthood. On the basis of this data, we recommend that neuro-imaging be considered in adults with Costello syndrome if they develop symptoms suggestive of a Chiari malformation. In the event of pubertal delay, endocrine investigations are indicated and hormone treatment may be required. Bone density assessments should be performed in adults with Costello syndrome, particularly in those with pubertal abnormalities. Screening for microscopic hematuria as a marker for bladder carcinoma may be indicated, although this requires further evaluation.

Surgical Aspects and Outcome of Delayed Tethered Cord Release

Out of a total of 550 children followed up at our spina bifida center, we report on 81 patients who were reoperated upon for secondary tethered cord syndrome between 1993 and 2000. In four cases with preceding severe progressive scoliosis, untethering was followed by surgical correction and stabilization of curvatures. In 77 patients, the indication for surgery was based on late progressive neurological deterioration. The current clinical relevance of competing etiologic factors such as symptomatic Chiari malformation, hydromyelia, and shunt dysfunction, requiring different clinical management, had been previously carefully excluded. The children underwent magnetic resonance imaging (MRI) or myelo-computed tomography (m-CT) to identify the morphologic extent of tethering and any associated spinal malformations such as dermoid tumors (19 cases) or diastematomyelia (9 cases). Surgery became faster and safer through bilateral dural incision, undercutting arachnoid adhesions along the tethered area, although this procedure increased the need for dural grafting. Complete release of the conus medullaris and cauda equina was achieved in a total of 75 cases (93 %) including those who had undergone prophylactic surgery. A mean follow-up of 4.8 years in 77 patients operated upon for late progressive neurological deterioration confirmed stabilization of presenting symptoms in 65 cases (84 %) with 20 of them (26 %) even showing significant improvement. In 12 patients (16 %), including all cases of incomplete untethering (n = 4), there was further deterioration.

Symptomatic Chiari I malformation in Kabuki syndrome

Kabuki (Niikawa-Kuroki) syndrome is associated with a characteristic facial appearance, cleft palate, congenital heart defects, and developmental delay. Structural brain anomalies have only occasionally been described in Kabuki syndrome. Chiari type I malformation, characterized by caudal herniation of the cerebellar tonsils through the foramen magnum, has been described only infrequently in association with defined syndromes and has been reported once in association with Kabuki syndrome. We report three additional children with Kabuki syndrome who have Chiari I malformation. Two children presented with chronic headaches and the third patient presented with gait abnormalities in adolescence. The incidence of Chiari I malformation may be higher than previously reported in Kabuki syndrome since it may not be diagnosed until later in childhood, whereas most reports of Kabuki syndrome are of young children. Further, symptoms of Chiari I anomaly can be somewhat nonspecific. Thus, we suggest that Chiari type I be considered in patients with Kabuki syndrome who present with persistent headache, neck pain, or other symptoms suggestive of Chiari I anomaly.

Foramen magnum cerebrospinal fluid flow characteristics in children with Chiari I malformation before and after craniocervical decompression

The Chiari I malformation presents significant challenges to clinicians because its pathophysiology is not well understood. In conducting cerebrospinal fluid (CSF) flow studies, investigators have attempted to correlate the clinical severity of these lesions with general flow velocity or bulk flow at the foramen magnum; however, these techniques have not allowed consistent prediction of symptomatology, explanation of the presence of syringomyelia, or the assessment of the hydrodynamic characteristics of the decompression. The authors used temporally and spatially resolved flow analyses to assess the characteristics of CSF flow in children with Chiari I malformation and the changes in these flow characteristics that occur after suboccipital decompression. The authors studied eight children with symptomatic Chiari I malformation with or without syringomyelia and two children without Chiari I malformation. All patients underwent phase-contrast magnetic resonance imaging before and after posterior fossa decompression. Velocity plots were displayed for each voxel. Several indices of CSF flow were developed to characterize the flow patterns associated with Chiari I malformation. In children with symptomatic Chiari I malformation, even though bulk flow or velocity is often normal, there was marked heterogeneity of flow at the foramen magnum. This was evident for several reasons: 1) an increase in cephalad and caudad peak velocities; 2) spatial inhomogeneity in velocities; 3) simultaneous bidirectional flow; and 4) substantial net craniad or caudad flows within particular voxels and subregions during the cardiac cycle. After posterior fossa decompression, the severity of these flow abnormalities decreased. Foramen magnum CSF flow in children with symptomatic Chiari I malformations is spatially and temporally heterogeneous, and this heterogeneity improves postoperatively. The authors propose that relying on mean flow parameters in patients with Chiari I malformation is no longer sufficient; instead, more elaborate techniques to analyze foramen magnum CSF flow have become necessary.

Treatment and management of the Chiari II malformation: an evidence-based review of the literature.

Multiple surgical strategies exist for the management of the symptomatic Chiari II malformation. To date, no comprehensive analysis of this medical literature in an attempt to seek out standards or guidelines has been performed, thus serving as the impetus for this present review. A computerized search of the database of the National Library of Medicine was performed on the English-language medical literature between 1966 and 2003. Terms searched for included hindbrain hernia, Chiari II, Arnold-Chiari, surgery, decompression, syringomyelia, and CSF shunts. All literature found was reviewed with associated references from these sources. Each piece of literature reviewed was scrutinized and guidelines developed utilizing the methodology used by the Guidelines for the Management of Acute Cervical Spine and Spinal Cord Injuries. All data reviewed were deemed to be Class III in nature. No standards or guidelines could be established from the available literature. There is significant debate and variable results in the current neurosurgical literature regarding the evaluation of shunt function vs. Chiari II decompression in patients with symptomatic hindbrain herniation. Multi-institutional prospective randomized trials are needed before any conclusions can be drawn regarding symptomatic Chiari II and its treatment paradigm. Until this time, clinical practice will be based on individual surgeons' experience, training, and personal beliefs.

Asymmetry of Tonsillar Ectopia in Chiari I Malformation

There has been almost no evaluation or discussion of the symmetry of tonsillar ectopia in the medical literature. We measured the degree of left and right tonsillar herniation in 42 pediatric patients with a symptomatic Chiari I malformation and made clinical/radiological correlations. 18% of all patients with tonsillar asymmetry had clinical symptoms or physical findings referable to the inequality of their hindbrain herniation. In addition, 95% of patients with a coexisting syringomyelia had a right cerebellar tonsillar herniation greater than the left. We hypothesize that slight differences in posterior cranial fossa morphology may physically allow for greater unilateral herniation of the left or right cerebellar tonsil, which may be manifested in a patient’s clinical presentation.

Headache and Chiari I malformation: clinical presentation, diagnosis, and controversies in management.

The Chiari I malformation is a cerebellar anomaly of uncertain origin, defined in part as tonsillar herniation of at least 3 to 5 mm below the foramen magnum; it is associated with crowding of the craniocervical junction. It is the most frequent of the Chiari malformations and is associated with headaches, syringohydromyelia, and hydrocephalus. The clinical manifestations are related to direct compression of neural tissues and abnormal cerebrospinal fluid dynamics. Common presentation is in adulthood, but there is increasing recognition in childhood. Incidental magnetic resonance imaging discovers Chiari I in one third of patients who do not have clinical symptoms. Headaches in the occipital-suboccipital region or those that are of cough-type suggest symptomatic Chiari I malformation. Suboccipital craniectomy is performed for patients with Chiari I malformation who have neural compression syndromes of the brainstem and spinal cord, select headache types, and other uncommon conditions that are not the topic of this review.

Treatment of the Chiari malformation with bone decompression without durotomy in children and young adults.

The purpose of this study was to provide more information on alternative operative approaches to the treatment of symptomatic Chiari type I and/or type II malformations in children and young adults. All patients were treated with craniocervical decompression without durotomy or duroplasty. The cervical decompression was carried on to the lowest level of tonsillar herniation. In 22 patients with symptomatic Chiari type I (4) and/or Chiari type II (18) malformation, there was total improvement in 12, partial improvement in 7, and no change in 3. There was no operative morbidity or mortality. Craniocervical decompression without durotomy may be a suitable treatment modality for symptomatic Chiari malformation in children and young adults.

Otologic manifestations of Chiari I malformation.

To assess the prevalence of otologic symptoms in patients undergoing surgical decompression for symptomatic Chiari I malformation. Cross-sectional, prospective, nonrandomized. Urban tertiary referral center. Patients with Chiari I malformation before surgical intervention. None. Results of completed questionnaire. Sixteen consecutive patients with Chiari I malformation completed the self-administered questionnaire. Eighty-one percent of patients reported episodic aural fullness, 81% reported tinnitus, 69% reported vertigo, and 56% reported fluctuating hearing loss. Headaches were reported as frequently as aural fullness and tinnitus. Most patients with Chiari I malformation have symptoms that mimic primary otologic pathologic changes. The existence of common pathophysiologic mechanisms is proposed.

Cerebellar fits in children with Chiari I malformation

The authors describe a series of children with Chiari I malformation who presented with fulminating symptoms of "cerebellar fits" characterized by drop attacks with or without deterioration of consciousness, opisthotonic posturing, and varying degrees of respiratory compromise. A retrospective analysis was undertaken of the medical records of 47 consecutive patients undergoing surgery for symptomatic Chiari I malformations at Rainbow Babies and Children's Hospital. Thirteen (28%) of the 47 patients presented with complaints consistent with cerebellar fits. Before the correct diagnosis was made, nine (69%) of the 13 children had previously undergone evaluation with electroencephalography and/or electrocardicography and Holter monitoring because of suspected cortical epilepsy or cardiogenic syncope. In each of the 13 children magnetic resonance imaging demonstrated pegged cerebellar tonsils herniated below the foramen magnum. A deep indentation or blanched discoloration of the cerebellar tonsils was noted in five (38%) of these 13 patients at the time of surgery. Of patients with symptomatic Chiari I malformations, the mean degree of tonsillar herniation was significantly less for those in whom cerebellar fits occurred than those in whom they were absent (8.8 mm and 13.9 mm, respectively; p = 0.007). In only one of the patients with cerebellar fits was a syrinx present, and this was a small focal lower thoracic collection. Spells resolved after surgery in all patients who presented with cerebellar fits. Cerebellar fits may mimic other disorders such as cardiogenic syncope and epileptic seizures. The correct diagnosis may be delayed or the conditions may be misdiagnosed by those who fail to consider Chiari I malformation as a cause of drop attacks, abnormal extensor posturing, and apneic spells in children. The response to decompressive surgery in these patients is gratifying.

Surgical Management of Chiari Type 1 Anomalies

A minimally invasive, posterior fossa bony decompression in the management of symptomatic Chiari type 1 anomalies in children was evaluated at the Children’s Hospital, Turin, Italy.

Toward a rational treatment of Chiari I malformation and syringomyelia

In patients with Chiari I malformation with and without associated syringomyelia, aberrant cerebrospinal fluid (CSF) dynamics and a spectrum of posterior fossa pathological findings are demonstrated. In this study, the authors test the validity of using prospective cardiac-gated phase-contrast cine-mode magnetic resonance (MR) imaging to define the malformation, delineate its pathophysiology, and assist in implementing a rational treatment plan. Eighty-five cases were prospectively analyzed using cine MR imaging. Sixty-five patients, adults and children, with symptomatic Chiari malformation, with and without syringomyelia, were surgically treated from 1990 to 1999. All patients underwent pre- and postoperative cine MR evaluation. Ten patients were treated after a previous surgical procedure had failed. To establish CSF flow characteristics and normative CSF profiles, 20 healthy volunteers were examined. Compared with normal volunteers, in Chiari I malformation patients with and without syringomyelia, uniformly abnormal craniocervical junction CSF flow profiles were revealed. After intradural exploration, nearly all patients with Chiari I malformation experienced clinical improvement and CSF flow profiles, paralleling those of normal volunteers, were shown. In all patients in whom treatment had failed, abnormal preoperative CSF flow profiles, which correlated with suspected physiological abnormalities and the pathological findings noted at reoperation, were demonstrated. Symptomatic Chiari I malformation is a dynamic process characterized by the impaction of the hindbrain in an abnormal posterior fossa. This compression obstructs the normal venting of CSF in and out of the craniocervical subarachnoid space, throughout the cardiac cycle. Therefore, decompression or enlargement of the posterior fossa to establish normal CSF pathways should be the primary goal of surgical intervention. Aberrant CSF flow appears to be only one aspect of the pathological condition found in patients with Chiari I malformation. Arachnoid scarring in the posterior fossa and selective vulnerability of the spinal cord may also be factors in the pathogenesis and maintenance of associated syringomyelia. Phase-contrast cine MR imaging is a useful tool in defining physiological and anatomical problems in patients with Chiari I and syringomyelia, and it can help guide an appropriate primary or salvage surgical therapy.

Cerebrospinal fluid flow dynamics study in Chiari I malformation: implications for syrinx formation

Cerebrospinal fluid (CSF) flow abnormalities are known to be present in Chiari I malformation and to underlie the origin and progression of associated syringomyelia. The incidence of syrinx formation, however, is variable for unknown reasons. The aim of this study was to investigate whether differences in CSF flow dynamics in patients with Chiari I malformation may account for the different clinical and radiological presentation. Presurgical and postsurgical phase-contrast magnetic resonance imaging investigations were prospectively conducted in 47 adult patients with symptomatic Chiari I malformation. Patients were divided into two groups according to the presence (32 cases) or absence (15 cases) of syrinx. Cerebrospinal fluid flow patterns were evaluated at four regions of interest: prebulbar cistern, foramen magnum, and the ventral and dorsal spinal subarachnoid spaces at the C-5 level. A temporal analysis of CSF flow waveforms was performed with measurement of cranial- and caudal-directed flow durations. All patients underwent a craniocervical decompressive procedure. Preoperatively, a prolonged caudal- directed (systolic) flow pattern was observed in patients with syringomyelia, as compared with normal control values obtained in 15 healthy volunteers. Conversely, a decreased systolic duration was observed in Chiari I patients who had malformation without syrinx. These trends were not statistically significant because of the considerable degree of overlap with the control values recorded in both groups. Additional comparison of the observed preoperative values obtained in patients with and those without syringomyelia indicated that the difference in systolic flow duration was significant at the ventral spinal subarachnoid space level (p = 0.003) and remarkable at the other levels, although not reaching statistical significance. Cerebrospinal fluid flow was minimal or absent at the foramen magnum (dorsal aspect) due to tonsillar herniation, precluding reliable quantitative measurement at this level. There was no evidence of communication between the fourth ventricle and syrinx in any case. Postoperatively, unobstructed CSF flow was recorded across the enlarged foramen magnum and into the artificial cisterna magna in all patients. A gradual restoration of near-normal flow patterns was observed in both groups. Inside the syrinx, fluid motion gradually tapered, no longer being detectable in 12 patients (37.5%) 1 year postsurgery. In patients with Chiari I malformation and associated syringomyelia different CSF flow patterns were demonstrated as compared with patients in whom syrinx was absent. Analysis of this study's findings supports the hypothesis that in Chiari I malformation an elongated systolic flow may prolong the condition of increased spinal subarachnoid pressure caused by the junctional obstruction, thus favoring CSF penetration into the spinal cord. It may be also proposed that a shortened systolic flow may be insufficient to maintain a hypertensive condition for enough time to induce syrinx formation.

Symptomatic Chiari type II malformation

The Chiari type II malformation is the leading cause of death in infants with myelomeningocele. The authors report 17 cases of symptomatic Chiari type II malformation occurring in two distinct age dependent population. In Group I, 13 neonates and infants in the first year of life presented with cranial nerve and brain stem dysfunction characterized by vocal cord paralysis, apnea, dysphagia and laryngeal stridor. In Group II, 4 patients developed signs and symptoms after the first year of life. In this group, the presentation was more insidious and included neck pain and cerebellar manifestations. The surgical treatment consisted initially in shunt implantation or revision and when there was no improvement, posterior fossa decompression was performed. The response to the surgical treatment differed considerably between the two groups: older patients improved promptly after surgery and there was no casualties; in newborn and infants, especially those under 6 months of age, the mortality rate was 46.1%. The authors stress that prompt diagnosis and surgical intervention should be performed in order to produce a favorable outcome.

Developmental normo-maturation of brainstem auditory evoked potentials in children with asymptomatic meningo-myelocele during the first year of life.

It is difficult to predict the onset of clinical symptoms due to Chiari II malformation. Brainstem auditory evoked potentials (BAEPs) may be useful to select potential candidates for surgery. We studied 158 BAEPs in 134 asymptomatic children with meningomyelocele (MMC) during the first year of life. Both wave latencies (WLs) and interpeak latencies (IPLs) in asymptomatic children with MMC gradually became shorter during the first year of life. In particular, the shortening of III-V IPLs was observed in the asymptomatic children with MMC from 2 or 3 weeks to 4-6 months of age. This may be a characteristic parameter of the development of the intrinsic brainstem function in patients with MMC. Comparison of these data on BAEPs in asymptomatic children with MMC with the published data on BAEPs in normal neonates and infants showed that the maturation of brainstem function was delayed in the asymptomatic children with MMC during the first year of life. These data on asymptomatic neonates and infants with MMC could potentially be a good reference for selecting the modalities of treatment in patients with MMC associated with symptomatic Chiari II malformation.

The Chiari II malformation: a surgical series.

Thirty patients between the ages of 7 months and 24 years were treated surgically for symptomatic Chiari II malformation at the Arkansas Children's Hospital. All patients underwent at least bony decompression of the malformation. Assessments of the patients' conditions were made at 6 weeks and 1 year after surgery, and complications of surgery were noted. For a majority of the patients, the presenting symptoms were resolved following treatment (74% at 6 weeks and 80% at 1 year). Partial resolution occurred in several of the patients (17% at 6 weeks and 14% at 1 year). A small number remained the same at 6 weeks (6%) and at 1 year (3%), while 1 patient was worse after surgery. Ten of the patients with complete resolution in the short term required repeat surgery an average of 49 months after their original operation, after which they again attained complete resolution of their symptoms. Scales for clinical, radiographic and operative grading of the patients' conditions as mild, moderate or severe were devised, and these were employed to characterize the condition of each patient. Patients in each grading category had good results, with rates of complete symptomatic resolution ranging from 67 to 100%. Severity in each category was found to be well correlated with eventual recurrence of symptoms and need for reoperation.

Comparison of simultaneous versus delayed ventriculoperitoneal shunt insertion in children undergoing myelomeningocele repair.

The timing of cerebrospinal fluid shunt insertion for those neonates with hydrocephalus in association with myelomeningocele remains controversial. To examine whether there was a difference in either the complication rate or mean hospital stay for neonates undergoing myelomeningocele repair and shunting under the same anesthetic (simultaneous group) versus those in whom shunt insertion was delayed for several days after myelomeningocele closure (sequential group), we reviewed the results obtained with these two approaches in a series of 69 consecutive patients who underwent both myelomeningocele closure and shunt insertion at our institution between 1987 and 1993. Twenty-one infants underwent simultaneous myelomeningocele repair and shunting, and 48 underwent sequential procedures. The decision to shunt concurrently with myelomeningocele repair rather than in a delayed fashion was based primarily on surgeon preference rather than initial head circumference, which did not differ significantly between the two groups. The frequency and type of hydrocephalus-related complications (e.g., wound leak, cerebrospinal fluid infection, or shunt malfunction) that occurred during the first 6 months after myelomeningocele closure were compared between the two groups. Neither the overall frequency of complications nor the frequency of cerebrospinal fluid infection, shunt malfunction, or symptomatic Chiari malformation differed significantly between the two groups. In contrast, there was a significantly higher rate of myelomeningocele wound leak in the sequential group versus the simultaneous group (eight versus zero; P = .05). Mean hospital stay for the sequential group was also significantly longer than the simultaneous group (22 days versus 13 days; P = .05). These results suggest that simultaneous myelomeningocele repair and ventriculoperitoneal shunt insertion reduces hospital stay and back wound morbidity in those patients with evidence of hydrocephalus at birth, without an inordinate increase in shunt-related complications.

The Effect of Early Craniocervical Decompression on Functional Outcome in Neonates and Young Infants with Myelodysplasia and Symptomatic Chiari II Malformations: Results from a Prospective Series

The indications for hindbrain decompression in neonates and young infants with spinal dysraphism who experience brain stem dysfunction in association with Chiari II malformations have remained controversial. This largely reflects the fact that the postoperative outcome in such patients has often been poor, which has supported the belief that much of the brain stem compromise in these patients is congenital and inherently irreversible. However, in a previous retrospective review of our operative results between 1975 and 1989, we noted that a significant component of the brain stem dysfunction in these children was an acquired phenomenon that potentially was reversible with prompt operative intervention. Accordingly, we hypothesized that with early craniocervical decompression, excellent functional outcome could be achieved in a majority of neonates and young infants with symptomatic Chiari II malformations. On the basis of this premise, we prospectively treated all such patients since 1989 with urgent brain stem decompression after other potential causes for brain stem dysfunction, such as progressive hydrocephalus, had been ruled out. All children underwent limited suboccipital craniectomies, cervical laminectomies extending beneath the inferior extent of the cerebellar tissue, and dural decompressions. The outcome in these patients has been favorable in comparison with previous studies. Ten of the 13 children treated according to this protocol recovered normal or nearly normal brain stem function shortly after decompression; 1 child had mild residual unilateral lower cranial nerve paresis. None of these children required a tracheostomy for ventilatory support, and only one required a temporary gastrostomy. The other three children all exhibited bilateral vocal cord paralysis and severe central hypoventilation by the time decompression was performed and failed to have any meaningful recovery of function. We conclude that early recognition of the symptoms of brain stem compromise in neonates and young infants with spinal dysraphism coupled with urgent evaluation and decompression are effective in producing prompt resolution of the brain stem dysfunction in most affected patients. Conversely, the prognosis for recovery is poor in children who exhibit bilateral vocal cord paralysis by the time of decompression.

The Effect of Early Craniocervical Decompression on Functional Outcome in Neonates and Young Infants with Myelodysplasia and Symptomatic Chiari II Malformations: Results from a Prospective Series

The Effect of Early Craniocervical Decompression on Functional Outcome in Neonates and Young Infants with Myelodysplasia and Symptomatic Chiari II Malformations: Results from a Prospective Series