Chiari I malformations and hydromyelia--complications

A complicated Chiari type 1 malformation and holocord syrinx as a likely cause for heel pain

BACKGROUND

Chiari malformations are a rare group of rhomboencephalic abnormalities involving the brain, craniocervical junction and spine. They may manifest in a variety of clinical presentations which relate to the variable involvement of the cerebellum, brainstem, lower cranial nerves, spinal cord and altered CSF flow dynamics.

METHOD

We report an unusual case of incidental diagnosis of a type I Chiari malformation with secondary cystic cerebellar tonsillar encephalomalacia and holocord syrinx following investigation of a 5YO girl presenting with heel swelling related to progressive neuropathic osteoarthropathy of the posterior calcaneal body and apophysis.

RESULT

The child was treated with decompressive suboccipital craniectomy and C1 laminectomy and tonsillar resection. Cerebellar tonsillar gliosis and cystic degeneration were confirmed on histopathology. Referral for ongoing engagement with occupational and physical therapy.

CONCLUSION

Most type I Chiari malformations in the paediatric population are incidental and asymptomatic. Neurological symptoms are typically mild and relate to altered CSF flow dynamics; however, we present a complex case of type I Chiari malformation with an unusual constellation of associated complications.

A Critical Update of the Classification of Chiari and Chiari-like Malformations

Chiari malformations are a group of craniovertebral junction anomalies characterized by the herniation of cerebellar tonsils below the foramen magnum, often accompanied by brainstem descent. The existing classification systems for Chiari malformations have expanded from the original four categories to nine, leading to debates about the need for a more descriptive and etiopathogenic terminology. This review aims to examine the various classification approaches employed and proposes a simplified scheme to differentiate between different types of tonsillar herniations. Furthermore, it explores the most appropriate terminology for acquired herniation of cerebellar tonsils and other secondary Chiari-like malformations. Recent advances in magnetic resonance imaging (MRI) have revealed a higher prevalence and incidence of Chiari malformation Type 1 (CM1) and identified similar cerebellar herniations in individuals unrelated to the classic phenotypes described by Chiari. As we reassess the existing classifications, it becomes crucial to establish a terminology that accurately reflects the diverse presentations and underlying causes of these conditions. This paper contributes to the ongoing discussion by offering insights into the evolving understanding of Chiari malformations and proposing a simplified classification and terminology system to enhance diagnosis and management.

Fourth ventricle to spinal subarachnoid space stenting in pediatric patients with refractory syringomyelia: case series and systematic review

A series of 5 patients treated with the fourth ventricle to spinal subarachnoid space stent (FVSSS) is presented. Indication for surgery, surgical technique, pre-operative and post-operative images, and outcome are analyzed. A systematic review of the pertinent literature has also been performed. This is a retrospective cohort review of a series of 5 consecutive patients with refractory syringomyelia who underwent a fourth ventricle to spinal subarachnoid space shunt surgery. The surgical indication was based on the presence of refractory syringomyelia in patients already treated for Chiari malformation or in patients who developed scarring at the level of the outlets of the fourth ventricle following posterior fossa tumor surgery. The mean age at FVSSS was 11.30 ± 5.88 years. Cerebral MRI revealed crowded posterior fossa, with a membrane at the level of the foramen of Magendie. Spinal MRI showed syringomyelia in all patients. Before surgery, the averages of the craniocaudal and the anteroposterior diameter were 22.66 and 1.01 cm, respectively, whereas the volume was 28.16 cm³. The post-operative period was uneventful in 4 out of 5 patients; one child died on the 1st post-operative day due to complications unrelated to surgery. In remaining cases, syrinx marked improvement. The post-operative volume was 1.47 cm³ with an overall reduction of 97.61%. With regard to literature, 7 articles with a total of 43 patients were analyzed. After FVSSS, syringomyelia reduction was observed in 86.04% of cases. Three patients underwent reoperation due to syrinx recurrence. Four patients presented a catheter displacement, one a wound infection and meningitis and one CSF leak requiring placement of a lumbar drain. FVSSS is highly effective in restoring CSF dynamics, with dramatic improvement of syringomyelia. In all our cases, the volume of the syrinx was reduced by at least 90%, with improvement/resolution of accompanying symptomatology. This procedure should be reserved to patients in which other causes of gradient pressure between the fourth ventricle and subarachnoid space are excluded, for example, tetraventricular hydrocephalus. Surgical procedure is not simple, because it requires meticulous microdissection of cerebello-medullary fissure and upper cervical spine, in already operated patients. To avoid migration of the stent, it should be carefully sutured to the dura mater or thick arachnoid membrane.

Symptomatic Cerebellar Ptosis After Wide Foramen Magnum Decompression for Chiari I Malformation

We present the case of a 22-year-old who developed severe neck pain within two weeks after undergoing posterior fossa decompression for a symptomatic Chiari I malformation. A diagnosis of cerebellar ptosis was made after magnetic resonance imaging (MRI) and he underwent a partial cranioplasty, following which his symptoms resolved. The pathology, diagnostic criteria, and management options are discussed.

Chiari Type 1 Malformation and Syringomyelia in Children: Classification and Treatment Options

Chiari type 1 malformation (CIM) is defined as tonsillar ectopia of >5 mm, while syringomyelia (SM) is defined as a cerebrospinal fluid (CSF)-filled cavity larger than 3 mm dissecting the spinal cord. Over the last decades, our understanding of these pathologies has grown; however, many controversies still exist almost in every aspect of CIM and SM, including etiology, indication for treatment, timing of treatment, surgical technique, follow-up regime, and outcome. This chapter provides a comprehensive overview on different aspects of CIM and SM and on the still existing controversies, based on the evidence presently available. Future directions for clinical research concerning CIM and SM treatment and outcome are elaborated and discussed as well.

Spinal cord stimulator for the treatment of central neuropathic pain secondary to cervical syringomyelia: illustrative case

BACKGROUND

Central neuropathic pain (CNP) of the cervical and/or thoracic spinal cord has many etiologies, both natural and iatrogenic. Frequently, CNP is medically refractory and requires surgical treatment to modulate the perception of pain. Spinal cord stimulation is a modality commonly used in adults to treat this type of refractory pain; however, it is rarely used in the pediatric population.

OBSERVATIONS

The authors reported a case involving a common pediatric condition, Chiari malformation type I with syrinx, that led to a debilitating complex regional pain syndrome. The associated life-altering pain was successfully alleviated following placement of a spinal cord stimulator.

LESSONS

CNP, or the syndromic manifestations of the pain (complex regional pain syndrome), can alter an individual's life in dramatic ways. Spinal cord stimulator placement in carefully selected pediatric patients should be considered in these difficult pain treatment paradigms.

Protrusion of brain stem into oropharynx in newborn: Unusual severe case of Chiari 1 malformation and Clival hypoplasia

Chiari 1 Malformation in children is defined as 6 mm or more caudal extension of cerebellar tonsils below the foramen magnum. It is one of the deformities in the spectrum of craniovertebral junction anomalies. We report an unusual case of newborn girl with hypoplasia of bassiocciput of the clivus and extension of brainstem into the oropharynx, in addition to extension of cerebellar tonsils below the foramen magnum. Right anterior arch and right posterior arch of C1 vertebra are absent. Dens of C2 vertebra is asymmetric. Laryngoscope showed a membrane covering the brainstem in the oropharynx. Endotracheal and orogastric tubes were placed. A ventriculo-peritoneal shunt was placed for hydrocephalus. The patient was discharged home at 4.5 months of age with home Hospice care. To the best of our knowledge, this has not been described in the literature. The case illustrates a rare defect in the clivus and unusual protrusion of brainstem into oropharynx.

The impact of neurosurgical technique on the short- and long-term outcomes of adult patients with Chiari I malformation

OBJECTIVE

This study is aimed to compare and evaluate any differences in clinical and radiological outcomes of different operative techniques of cranio-cervical decompression (CCD) performed in adults with symptomatic Chiari malformation type I (CM-1) within a single tertiary neurosurgical center.

METHODS

A retrospective review using the Hospital theatre management system (ORSOS) and records of patients who underwent CCD for CM-1 between January 2011 and October 2019 was performed. Patients were divided in three cohorts according to the operative technique used: an extradural osteo-ligamentous decompression (BD), BD followed by dural opening either without duraplasty (DOWD) or plus duroplasty (DOPD). The primary clinical outcome was measured by utilizing the Chicago Chiari Outcome Scale (CCOS). Syrinx outcome was measured on post-op MRI. Statistical analysis was performed using IBM SPSS 24 with α = 0.05.

RESULTS

67 adults underwent 69 CCD: 10 BD, 29 DOWD and 30 DOPD. Median follow-up was 47.3 months (Interquartile Range (IQR) 26.3-73.7). Patients who underwent DOPD had a shorter median hospital stay (p-value 0.001), fewer unplanned readmissions (p-value 0.015), a higher median CCOS (p-value 0.001) and a lower post-operative complications rate (p-value 0.001) compared to patients who underwent DOWD. BD revealed a 40 % failure rate and was ineffective in cases with syringomyelia.

CONCLUSION

Better clinical outcomes, lower complication risk, and short duration of hospital stay were associated with patients who underwent dural opening with augmentative watertight duraplasty. Bony decompression alone despite being a very safe technique, does not appear to be reliable and effective in controlling and relieving the clinical symptoms and the syringomyelia of adult patients with CM-1.

The Perplexity Surrounding Chiari Malformations - Are We Any Wiser Now?

Chiari malformations are a diverse group of abnormalities of the brain, craniovertebral junction, and the spine. Chiari 0, I, and 1.5 malformations, likely a spectrum of the same malformation with increasing severity, are due to the inadequacy of the para-axial mesoderm, which leads to insufficient development of occipital somites. Chiari II malformation is possibly due to nonclosure of the caudal end of the neuropore, with similar pathogenesis in the rostral end, which causes a Chiari III malformation. There have been significant developments in the understanding of this complex entity owing to insights into the pathogenesis and advancements in imaging modalities and neurosurgical techniques. This article aims to review the different types and pathophysiology of the Chiari malformations, along with a description of the various associated abnormalities. We also highlight the role of ante- and postnatal imaging, with a focus on the newer techniques in the presurgical evaluation, with a brief mention of the surgical procedures and the associated postsurgical complications.

Persistent Syringomyelia After Posterior Fossa Decompression for Chiari Malformation

BACKGROUND

Chiari malformation (CM) is often comorbid with syringomyelia. The treatment of CM via posterior fossa decompression (PFD) may not improve syringomyelia in up to 40% of patients, based on historical cohorts. Management of these patients is problematic, as both reoperation and syrinx shunting have high failure rates in the long term.

METHODS

We retrospectively reviewed our cases in which patients with CM type 1 or 1.5 and syringomyelia underwent PFD without postoperative improvement in syringomyelia. Symptomatology and radiographic measurements were collected at presentation and on the first and latest available postoperative scans and analyzed. We present 2 cases to illustrate the challenges in the management of these patients.

RESULTS

Our cohort consisted of 48 consecutive patients with CM and syringomyelia who underwent PFD. Of these, 41 patients had postoperative improvement in or resolution of syringomyelia. We subsequently studied the cohort of 7 patients who underwent PFD with (n = 5) or without (n = 2) durotomy and demonstrated worsening of syringomyelia following surgery. This cohort had mean (±SEM) preoperative syrinx area of 23.9 ± 10.0 mm². Postoperatively, the mean syrinx area increased to 40.5 ± 9.6 mm² and 57.3 ± 12.5 mm² on the first and latest postoperative scans available (P = 0.02), for an increase of 106.9% ± 94.4% and 186.0% ± 107.4% (P = 0.04). Presenting symptoms included occipital headache, paresthesias, visual deterioration, and paraspinal pain. On last follow-up (mean 13.9 ± 4.9 months), the majority of symptoms were resolved in this cohort, despite persistence of syringomyelia.

CONCLUSIONS

In this small cohort of unique patients, syrinx resolution was not achieved via decompression surgery. Despite "radiographic failure," good symptom control was achieved, with most patients remaining or becoming asymptomatic postoperatively, thus supporting our rationale for what has largely been a conservative approach in this population.

Cerebellar slump following removal of haematoma: a manifestation of hydrocephalus?

Cerebellar slump is a rarely reported complication of craniocervical decompression for Chiari malformation. This is known to occur following an oversized bony decompression of the cranio-vertebral junction. The index case is the first reported which developed this phenomenon following cerebellar hemispheric haematoma removal. Disturbance of CSF circulation in the presence of a calvarial defect may have been the cause. The patient was treated with a titanium mesh cranioplasty of the posterior cranial defect, followed by a ventriculo-peritoneal shunt.

Management of hydrocephalus and subdural hygromas in pediatric patients after decompression of Chiari malformation type I: case series and review of the literature

OBJECTIVE

Hydrocephalus associated with subdural hygromas is a rare complication after decompression of Chiari malformation type I (CM-I). There is no consensus for management of this complication. The authors present a series of 5 pediatric patients who underwent CM-I decompression with placement of a dural graft complicated by posterior fossa hygromas and hydrocephalus that were successfully managed nonoperatively.

METHODS

A retrospective review over the last 5 years of patients who presented with hydrocephalus and subdural hygromas following foramen magnum decompression with placement of a dural graft for CM-I was conducted at 2 pediatric institutions. Their preoperative presentation, perioperative hospital course, and postoperative re-presentation are discussed with attention to their treatment regimen and ultimate outcome. In addition to reporting these cases, the authors discuss all similar cases found in their literature review.

RESULTS

Over the last 5 years, the authors have encountered 194 pediatric cases of CM-I decompression with duraplasty equally distributed at the 2 institutions. Of those cases, 5 pediatric patients with a delayed postoperative complication involving hydrocephalus and subdural hygromas were identified. The 5 patients were managed nonoperatively with acetazolamide and high-dose dexamethasone; dosages of both drugs were adjusted to the age and weight of each patient. All patients were symptom free at follow-up and exhibited resolution of their pathology on imaging. Thirteen similar pediatric cases and 17 adult cases were identified in the literature review. Most reported cases were treated with CSF diversion or reoperation. There were a total of 4 cases previously reported with successful nonoperative management. Of these cases, only 1 case was reported in the pediatric population.

CONCLUSIONS

De novo hydrocephalus, in association with subdural hygromas following CM-I decompression, is rare. This presentation suggests that these complications after posterior fossa decompression with duraplasty can be treated with nonoperative medical management, therefore obviating the need for CSF diversion or reoperation.

Cerebrospinal fluid disturbance in overweight women after occipitocervical decompression in Chiari malformation type I

BACKGROUND

Cerebrospinal fluid disturbance (CSFD) is a well-known complication after occipitocervical decompression (OCD) in patients with Chiari malformation type I (CMI). There is scarce data focusing on preoperative patients' factors predisposing to development of CSF disturbance. The aim of this study is to evaluate a prognostic value of some patients' factors in the prediction of CSFD after OCD in CMI patients.

MATERIALS AND METHODS

We undertook a 10-year (2003-2013) retrospective study of all OCD in patients with CMI performed at Sahlgrenska IC, Sahlgrenska University Hospital, Sweden. A total of 52 consecutive patients were obtained from the operation database and we excluded one patient who was previously diagnosed with normal-pressure hydrocephalus. Data regarding preoperative age, body mass index, gender, degree of tonsillar herniation and syrinx were registered. Development of CSFD after OCD was noted.

RESULTS

Of the 51 patients reviewed, six had CSFD after OCD and were managed using a form of CSF diversion procedure. All of the patients who developed CSFD were females. They had a mean body mass index of 32.3 compared to a mean of 24.3 in patients without CSFD (p = 0.0011). There was no difference between the two groups with regard to the other examined patient factors.

CONCLUSIONS

CSF diversion was needed in six consecutive adult Chiari malformation type I patients who underwent occipitocervical decompression. All patients with postoperative CSFD were female and their mean BMI was significantly higher than patients without this complication.

Natural and surgical history of Chiari malformation Type I in the pediatric population

OBJECT The natural and surgical history of Chiari malformation Type I (CM-I) in pediatric patients is currently not well described. In this study the authors discuss the clinical and radiological presentation and outcomes in a large cohort of pediatric CM-I patients treated with either conservative or surgical management. METHODS The authors retrospectively reviewed 95 cases involving pediatric patients with CM-I who presented between 2004 and 2013. The patients ranged in age from 9 months to 18 years (mean 8 years) at presentation. The cohort was evenly split between the sexes. Twenty-five patients underwent posterior fossa decompression (PFD) with either dural splitting or duraplasty. Seventy patients were managed without surgery. Patients were followed radiologically (mean 44.8 months, range 1.2-196.6 months) and clinically (mean 66.3 months, range 1.2-106.5 months). RESULTS Seventy patients were treated conservatively and followed with serial outpatient neurological and radiological examinations, whereas 25 patients were treated with PFD. Of these 25 surgical patients, 11 were treated with duraplasty (complete dural opening) and 14 were treated with a dura-splitting technique (incomplete dural opening). Surgical intervention was associated with better clinical resolution of symptoms and radiological resolution of tonsillar ectopia and syringomyelia (p = 0.0392). Over the course of follow-up, 20 (41.7%) of 48 nonsurgical patients who were symptomatic at presentation experienced improvement in symptoms and 18 (75%) of 24 symptomatic surgical patients showed clinical improvement (p = 0.0117). There was no statistically significant difference in resolution of symptoms between duraplasty and dura-splitting techniques (p = 0.3572) or between patients who underwent tonsillectomy and tonsillopexy (p = 0.1667). Neither of the 2 patients in the conservative group with syrinx at presentation showed radiological evidence of resolution of the syrinx, whereas 14 (87.5%) of 16 patients treated with surgery showed improvement or complete resolution of syringomyelia (p = 0.0392). In the nonsurgical cohort, 3 patients (4.3%) developed new or increased syrinx. CONCLUSIONS The overwhelming majority of CM-I patients (92.9%) managed conservatively do not experience clinical or radiological progression, and a sizeable minority (41.7%) of those who present with symptoms improve. However, appropriately selected symptomatic patients (sleep apnea and dysphagia) and those presenting with syringomyelia should be considered surgical candidates because of the high rates of clinical (75%) and radiological improvement (87.5%).

Pediatric and adult Chiari malformation Type I surgical series 1965-2013: a review of demographics, operative treatment, and outcomes

OBJECT

Chiari malformation Type I (CM-I) is a hindbrain disorder associated with elongation of the cerebellar tonsils, which descend below the foramen magnum into the spinal canal. It occurs in children and adults. Clinical symptoms mainly develop from alterations in CSF flow at the foramen magnum and the common subsequent development of syringomyelia.

METHODS

The authors reviewed English-language reports of pediatric, adult, and combined (adult and pediatric) surgical series of patients with CM-I published from 1965 through August 31, 2013, to investigate the following: 1) geographical distribution of reports; 2) demographics of patients; 3) follow-up lengths; 4) study durations; 5) spectrum and frequency of surgical techniques; 6) outcomes for neurological status, syrinx, and headache; 7) frequency and scope of complications; 8) mortality rates; and 9) differences between pediatric and adult populations. Research and inclusion criteria were defined, and all series that contained at least 4 cases and all publications with sufficient data for analysis were included.

RESULTS

The authors identified 145 operative series of patients with CM-I, primarily from the United States and Europe, and divided patient ages into 1 of 3 categories: adult (>18 years of age; 27% of the cases), pediatric (≤18 years of age; 30%), or unknown (43%). Most series (76%) were published in the previous 21 years. The median number of patients in the series was 31. The mean duration of the studies was 10 years, and the mean follow-up time was 43 months. The peak ages of presentation in the pediatric studies were 8 years, followed by 9 years, and in the adult series, 41 years, followed by 46 years. The incidence of syringomyelia was 65%. Most of the studies (99%) reported the use of posterior fossa/foramen magnum decompression. In 92%, the dura was opened, and in 65% of these cases, the arachnoid was opened and dissected; tonsillar resection was performed in 27% of these patients. Postoperatively, syringomyelia improved or resolved in 78% of the patients. Most series (80%) reported postoperative neurological outcomes as follows: 75% improved, 17% showed no change, and 9% experienced worsening. Postoperative headaches improved or resolved in 81% of the patients, with a statistical difference in favor of the pediatric series. Postoperative complications were reported for 41% of the series, most commonly with CSF leak, pseudomeningocele, aseptic meningitis, wound infection, meningitis, and neurological deficit, with a mean complication rate of 4.5%. Complications were reported for 37% of pediatric, 20% of adult, and 43% of combined series. Mortality was reported for 11% of the series. No difference in mortality rates was seen between the pediatric and adult series.

CONCLUSIONS

Before undergoing surgical treatment for CM-I, symptomatic patients and their families should be given clear information about the success of treatment and potential complications. Furthermore, surgeons may benefit from comparing published data with their own. In the future, operative CM-I reports should provide all details of each case for the purpose of comparison.

Surgical outcomes after posterior fossa decompression with and without duraplasty in Chiari malformation-I

INTRODUCTION

Chiari malformation-I (CM) is one of the most controversial entities in the contemporary neurosurgical literature. Posterior fossa decompression (PFD) is the preferred treatment for CM with and without syringomyelia. A variety of surgical techniques for PFD have been advocated in the literature. The aim of this study was to evaluate our results of surgically treated patients for CM-I with and without syringomyelia; using extradural dura-splitting and intradural intraarachnoid techniques.

METHODS

A retrospective review of the medical records of all the patients undergoing PFD was conducted. Symptomatic patients with tonsillar herniation≥3-mm below the foramen magnum on neuroimaging, and CSF flow void study demonstrating restricted or no CSF flow at the craniocervical junction, were offered surgical treatment. In patients without syringomyelia, extradural decompression with thinning of the sclerotic tissue at the cervicomedullary junction and splitting of outer dural layer was performed. In patients with syringomyelia, the dura was opened and an expansile duraplasty was performed.

RESULTS

The mean age of 8 males and 34 females was 33.8 years (range, 16-58 years). Headache (39/41; 95%), and/or tingling and numbness (17/41; 42%) were the most common presenting symptoms. The syrinx was associated with CM-I in 5/41 (12%) patients. PFD without durotomy was performed in 29/41 (73%) patients. The mean duration of preoperative symptoms was significantly longer in duraplasty group (4.6 versus 1.7 years, P=0.005, OR=0.48, CI=0.29-0.8). The use of duraplasty was significantly associated with presence of complications (P=0.004, OR=0.5, CI=0.3-0.8) and longer duration of hospital stay (P=0.03, OR=2.7, CI=1.1-6.8). The overall complication rate was 6/41(15%) patients. The overall improvement rate was evident in 84% (36/41); 12% (5/41) were stable; and 5% (2/41) had worsening of symptoms. The history of prior CM decompression was associated with unfavorable outcomes (P=0.04, OR=14, CI=1.06-184). One patient experienced recurrence one year after the PFD with duraplasty.

CONCLUSION

The present study reports favorable surgical outcomes with extra-dural decompression of the posterior fossa in patients CM-I without syringomyelia. For patients with syringomyelia and history of prior PFD, intradural intra-arachnoid decompression is required. The prior history of decompression was associated with unfavorable outcomes. The use of duraplasty was associated with longer duration of hospital stay and higher complication rate. Further large cohort prospective study is needed to provide any recommendation on the indication of intra or extradural decompression for a given CM-I patient.

The Chiari malformations: a review with emphasis on anatomical traits

Hindbrain herniations come in many forms and have been further subdivided as their original descriptions. For cerebellar tonsillar ectopia, they can be divided into two categories, acquired and congenital. Acquired hindbrain herniations are due to increased intracranial pressure caused by certain conditions such as trauma or brain tumor. Although the mechanism for their formation is not clear, congenital hindbrain herniation makes up the majority of these congenital malformations. Furthermore, these malformations are often found to harbor additional anatomical derailments in addition to the hindbrain herniation whether it be the cerebellar tonsils (Chiari I malformation) or the cerebellar vermis (Chiari II malformation). This article reviews these forms of cerebellar ectopia and describes the details of their anomalous anatomy. Moreover, this article compares and contrasts the differing embryological theories found in this literature.

Asymmetry of tonsillar ectopia, syringomyelia and clinical manifestations in adult Chiari I malformation

BACKGROUND

The asymmetry of tonsillar ectopia, syringomyelia, and clinical manifestations, and their correlations in adult Chiari I malformation (CIM) are seldom discussed.

METHODS

Clinical and imaging data of 104 consecutive adult patients with CIM and syringomyelia were retrospectively reviewed. A method was devised to quantify tonsillar and syrinx asymmetry. Correlations between the asymmetrically displaced cerebellar tonsils, the side of the syrinx, clinical presentations, and the curve direction of scoliosis were investigated.

RESULTS

Tonsillar ectopia was left dominant in 46 patients (44.2 %), right dominant in 49 (47.1 %), and symmetrical in nine (8.7 %). The syrinx was left deviated in 44 patients (42.3 %), right deviated in 48 (46.2 %), and centrally located in 12 (11.5 %). A significant correlation was observed between the side of tonsillar herniation and the side of the syrinx (p < 0.001), and also between the descending ratio of tonsillar herniation and the deviation ratio of the syrinx (p < 0.001). The main side the of clinical presentations showed significant correlation with the dominant side of tonsillar herniation (p = 0.009) and the side of syrinx deviation (p = 0.012). In the 49 patients (47.1 %) with associated scoliosis, the curve direction was significantly related to not only the dominant side of tonsillar ectopia (p = 0.0,28) but also the deviated side of the syrinx (p = 0.044). Moreover, the curve magnitude was significantly correlated with the distance of the tonsillar herniation (p = 0.001).

CONCLUSIONS

In adult CIM, most tonsillar herniations are asymmetrical and most syringomyelia is eccentrical. We speculate that the dominant side of tonsillar herniation determines the side of syrinx deviation, which in turn determines the main side of clinical presentations and the convex side of scoliosis. Our results suggest that the more the descended tonsil tilts to one side, the more the syrinx tilts to the same side.

Dural sinus filling defect: intrasigmoid encephalocele

Filling defects of dural venous sinuses are considered to be a challenging problem especially in case of symptomatic patients. Many lesions have to be ruled out such as sinus thrombosis, arachnoid granulations and tumours. Encephalocele into dural sinus is also a rare cause of these filling defects of dural sinuses. Here, we report an extremely rare case with spontaneous occult invagination of temporal brain tissue into the left sigmoid sinus and accompanying cerebellar ectopia.

Surgical management of symptomatic Chiari II malformation in infants and children

PURPOSE

Variation exists in the surgical methods employed for decompression of Chiari II malformation (CIIM), yet an evaluation of these techniques has not been performed. The purpose of this study was to assess the efficacy of bony decompression (cervical laminectomy alone versus suboccipital craniectomy with laminectomy) with or without dural augmentation for the treatment of symptomatic CIIM.

METHODS

Clinical records of children 0-18 years of age who underwent surgical repair of myelomeningocele or CIIM decompression at St. Louis Children's Hospital (SLCH) from 1990-2011 were reviewed. Signs/symptoms prompting decompression, surgical technique, operative parameters, and clinical outcomes were recorded for analysis.

RESULTS

Thirty-three subjects were treated at SLCH for CIIM decompression. Twenty-six subjects underwent bony decompression only (21 cervical laminectomy alone, 5 suboccipital craniectomy + cervical laminectomy) while seven underwent bony decompression with upfront dural augmentation (three cervical laminectomy alone, four suboccipital craniectomy + cervical laminectomy). Median follow up was 5.0 years (range, 3 months-19 years). Symptomatic improvement was noted in 20/33 subjects (60.6%). Sixty-two (61.5%) percent of children who underwent bony decompression had symptomatic improvement, compared with 57.1% of those with upfront dural augmentation (p = 0.37). Estimated blood loss, operative time, and length of perioperative hospital stay appeared lower in the bony decompression group but were not statistically different in this limited cohort.

CONCLUSIONS

The results from this series suggest that bony CIIM decompression via tailored cervical laminectomies alone, without suboccipital craniectomy or upfront dural augmentation, is a reasonable initial management approach for decompression of symptomatic CIIM.

The association of neural axis and craniovertebral junction anomalies with scoliosis in Rubinstein-Taybi syndrome

OBJECT

Rubinstein-Taybi syndrome (RSTS) is a rare condition with characteristic genetic and clinical features. The presence of variable vertebral and neural axis abnormalities has been reported in the literature. We describe the possible association of multiple different spinal anomalies in these patients.

RESULTS

The radiological exams of two RSTS patients (a female and male of 11 and 13 years) have been reviewed. Both patients presented the simultaneous association of craniovertebral junction bony abnormalities (occipito-C1 condyle subluxation and posterior C2-C3 arches fusion), Chiari I malformation, spinal cord syrinx, low-lying conus medullaris, and scoliosis.

CONCLUSION

An association of different spinal cord anomalies is possible in RSTS patients and has to be investigated with a comprehensive neuroimaging study in order to address the proper treatment and prevent the development of neurologic deficits.

Surgical Treatment of Chiari I Malformation—Analysis of Intraoperative Findings, Complications, and Outcome for 371 Foramen Magnum Decompressions

BACKGROUND:

Foramen magnum decompression is widely accepted as the treatment of choice for Chiari I malformation. However, important surgical details of the procedure are controversial.

OBJECTIVE:

This study analyzes 371 decompressions focusing on intraoperative findings, analysis of complications, and long-term outcomes.

METHODS:

Among 644 patients between 1985 and 2010, 359 patients underwent 371 decompressions. Surgery for symptomatic patients consisted of suboccipital craniectomy, C1 laminectomy, arachnoid dissection, and duraplasty. Short-term results were determined after 3 months; long-term outcomes were evaluated with Kaplan-Meier statistics.

RESULTS:

The mean age was 40 ± 16 years; mean follow-up was 49 ± 56 months; 75.8% demonstrated syringomyelia. The complication rate was 21.8% with permanent surgical morbidity of 3.2% and surgical mortality of 1.3%. Of the patients, 73.6% reported improvement after 3 months; 21% were unchanged. Overall, 14.3% demonstrated a neurological deterioration within 5 years and 15.4% within 10 years. The severity of neurological symptoms correlated with the grade of arachnoid pathology. Outcome data correlated with the number of previous decompressions, severity of arachnoid pathology, handling of the arachnoid, type of duraplasty, and surgical experience. First-time decompressions with arachnoid dissection and an alloplastic duraplasty resulted in surgical morbidity for 2.0%, a 0.9% mortality rate, postoperative improvement after 3 months for 82%, and neurological recurrence rates of 7% after 5 years and 8.7% after 10 years.

CONCLUSION:

Arachnoid pathology in Chiari I malformation has an impact on clinical symptoms and postoperative results. Decompressions with arachnoid dissection and an alloplastic duraplasty performed by surgeons experienced with this pathology offer a favorable long-term prognosis.

Unusual association of Arnold-Chiari malformation and vitamin B12 deficiency

Arnold-Chiari malformations are a group of congenital or acquired defects associated with the displacement of cerebellar tonsils into the spinal canal. First described by Chiari (1891), this has various grades of severity and involves various parts of neuraxis, for example, cerebellum and its outputs, neuro-otological system, lower cranial nerves, spinal sensory and motor pathways. The symptomatology of Arnold-Chiari malformations may mimic multiple sclerosis, primary headache syndromes, spinal tumours and benign intracranial hypertension. We highlighted a case of Chiari type I malformation, who presented with posterolateral ataxia associated with significant vitamin B(12) deficiency. The patient was supplemented with vitamin B(12) injections and showed remarkable improvement at follow-up after 3&emsp14;months.

Paroxysmal neuropathic pain in an adolescent female with syringomyelia: a review of literature

Paroxysmal neuropathic pain is an uncommon complaint among pediatric patients visiting the emergency department. It is a rare presentation in children with syringomyelia. Patients with syringomyelia may present with a variety of pain symptoms. It is the site and extension of the syrinx, which determines the character of pain. We report an adolescent with Chiari malformation type 1 with syringomyelia who presented with neuropathic pain, dysesthesia, and absent triceps (C7) reflex. The pertinent literature is reviewed.

Chiari malformation Type I and syrinx in children undergoing magnetic resonance imaging

OBJECT

Chiari malformation Type I (CM-I) with an associated spinal syrinx is a common pediatric diagnosis. A better understanding of the relative age-related prevalence and MR imaging characteristics of these associated conditions may lead to improved treatment decisions.

METHODS

The authors performed a retrospective review of 14,116 consecutive individuals 18 years of age or younger who had undergone brain or cervical spine MR imaging at the University of Michigan between November 1997 and August 2008. In the patients with CM-I, demographic, clinical, and radiographic information was recorded.

RESULTS

Five hundred nine children (3.6%) with CM-I were identified. Among these patients, 23% also had a spinal cord syrinx, and 86% of the syringes were found in the cervical spine. The MR imaging prevalence of CM-I with a syrinx was 1.2% in girls and 0.5% in boys (p < 0.0001). The severity of impaired CSF flow at the foramen magnum was associated with the amount of tonsillar herniation (p < 0.0001) and conformation of the tonsils (p < 0.0001). Patients with CM-I were treated surgically in 35% of cases; these patients exhibited more severe tonsillar herniation (p < 0.0001) and impaired CSF flow (p < 0.0001) as compared with those who did not undergo surgery. On imaging, 32% of all the patients with CM-I were considered symptomatic by the treating physician. Patients were more likely to be considered symptomatic if they were female, had a syrinx, displayed abnormal tonsillar pulsations, or had a greater amount of tonsillar herniation.

CONCLUSIONS

In this study the authors describe the age-related prevalence and MR imaging characteristics of CM-I and its association with a syrinx and other abnormalities in a large group of children who underwent MR imaging for any indication. Syringes are more common in older children, in girls, and in patients with a greater degree of tonsillar descent and CSF flow impairment.

Natural history of Chiari malformation Type I following decision for conservative treatment

OBJECT

The natural history of the Chiari malformation Type I (CM-I) is incompletely understood. The authors report on the outcome of a large group of patients with CM-I that were initially selected for nonsurgical management.

METHODS

The authors identified 147 patients in whom CM-I was diagnosed on MR imaging, who were not offered surgery at the time of diagnosis, and in whom at least 1 year of clinical and MR imaging follow-up was available after the initial CM-I diagnosis. These patients were included in an outcome analysis.

RESULTS

Patients were followed clinically and by MR imaging for a mean duration of 4.6 and 3.8 years, respectively. Of the 147 patients, 9 had new symptoms attributed to the CM-I during the follow-up interval. During this time, development of a spinal cord syrinx occurred in 8 patients; 5 of these patients had a prior diagnosis of a presyrinx state or a dilated central canal. Spontaneous resolution of a syrinx occurred in 3 patients. Multiple CSF flow studies were obtained in 74 patients. Of these patients, 23 had improvement in CSF flow, 39 had no change, and 12 showed worsening CSF flow at the foramen magnum. There was no significant change in the mean amount of cerebellar tonsillar herniation over the follow-up period. Fourteen patients underwent surgical treatment for CM-I. There were no differences in initial cerebellar tonsillar herniation or CSF flow at the foramen magnum in those who ultimately underwent surgery compared with those who did not.

CONCLUSIONS

In patients with CM-Is that are selected for nonsurgical management, the natural history is usually benign, although spontaneous improvement and worsening are occasionally seen.

Patients with Chiari malformation Type I presenting with acute neurological deficits: case series

OBJECT

A subset of patients with Chiari malformation Type I (CM-I) presented with acute onset of a neurological deficit. In this study the authors summarize their experience with these patients' clinical presentation, imaging results, timing of surgery, and outcome following decompression.

METHODS

The authors reviewed clinical records, imaging studies, and operative notes from all patients undergoing posterior fossa decompression for CM-I at St. Louis Children's Hospital from 1990 to 2008. Of the 189 patients who underwent surgery, 6 were identified with the acute onset of a neurological deficit at presentation.

RESULTS

All 6 children (age range 3-14 years, 3 boys and 3 girls) had either syringomyelia (5 patients) or T2 signal changes in the spinal cord (1 patient) and CM-I on initial MR imaging. Three patients presented after minor trauma (1 with paraparesis, 2 with sensory deficits). Three patients presented without a clear history of trauma (1 with abrupt onset of spontaneous dysphagia and ataxia, 2 with sensory deficits). Decompression was performed at a mean 7.7 ± 4.9 days after symptom onset (7.0 ± 1.6 days after neurosurgical evaluation). In 1 patient, symptoms had resolved by the time of surgery; in the remainder of the patients, clear improvements were noted within 2 weeks of surgery, with complete resolution of symptoms by 12 months postoperatively. Follow-up MR images were obtained in 4 patients, demonstrating improvement in the extent of the syrinx in each patient.

CONCLUSIONS

Children with CM-I and syringomyelia can develop acute spinal cord or bulbar deficits with relatively minor head or neck injuries. The prognosis for symptomatic improvement in the observed deficit is good, with each patient in our series showing resolution of deficits over time. However, based on this relatively limited experience, the authors suggest that patients who present with an acute neurological deficit and are found to have CM-I be managed with early posterior fossa decompression. Patients with CM-I and syringomyelia may be at higher risk of acute neurological deficit than those without a syrinx.

Concurrent Chiari decompression and spinal cord untethering in children: feasibility in a small case series

BACKGROUND AND PURPOSE

We describe the rationale and safety of concurrent decompression of Chiari type 1 malformation (CM1) and untethering of the spinal cord. Spinal cord traction is considered one of the pathogenic mechanisms involved in the development of CM, and 14% of patients with CM1 have tethered cord syndrome (Milhorat et al., Surg Neurol 7:20-35, 2009; Roth, Neuroradiology 21:133-138, 1981; Royo-Salvador, Rev Neurol 24:937-959, 1996; Royo-Salvador et al., Acta Neurochir 147:515-523, 2005). Therefore, intraspinal anomalies that require intervention are commonly treated before surgical decompression of Chiari malformation (Cheng et al., Neurologist 8:357-362, 2002; Menezes, Pediatr Neurosurg 23:260-269, 1995; Milhorat et al., Surg Neurol 7:20-35, 2009; Royo-Salvador et al., Acta Neurochir 147:515-523, 2005; Schijman and Steinbok, Childs Nerv Syst 20:341-348, 2004; Yamada et al., Neurol Res 26:719-721, 2004). However, in the interval between the spinal cord untethering and the decompression surgery, patients may continue to suffer from the untreated symptoms of CM. In a series of four patients with concurrent severe and progressive symptoms referable to both conditions, we performed both surgeries simultaneously.

METHODS

Charts of four patients who underwent concurrent Chiari decompression and spinal cord untethering were reviewed.

RESULTS

All patients tolerated the procedures well without complication. They reported significant or complete early postsurgical resolution of headaches and ambulating difficulties. On average, patients started to walk on postoperative day 3 (3 ± 1 days) and were discharged on hospital day 6 (6 ± 1 days). No patient experienced a persistent subcutaneous or transcutaneous cerebrospinal fluid leak. Subsequent postoperative courses were uneventful.

CONCLUSION

Concurrent Chiari decompression and untethering of the spinal cord is a feasible option and in some patients may be preferred in lieu of staged procedures.

Suboccipital craniectomy with or without duraplasty: what is the best choice in patients with Chiari type 1 malformation?

The best surgical treatment for Chiari malformation is unclear, especially in patients with syringomyelia. We reviewed the records of 16 patients who underwent suboccipital craniectomy at our institution between 2005 and 2008. Of the six patients who did not undergo duraplasty, four showed improvement postoperatively. Two patients without syringomyelia showed improvement postoperatively. Of the four patients with syringomyelia, three showed improvement, including two with a decrease in the cavity size. One patient showed improvement in symptoms but the syringomyelia was unchanged. The cavity size increased in the one patient who did not show improvement. Among the 10 patients who underwent duraplasty, improvements were noted in four of the five patients without syringomyelia and in all of the five with syringomyelia. There is a suggestion that patients with syringomyelia may have a higher likelihood of improvement after undergoing duraplasty.

Neurosurgical management of spinal dysraphism and neurogenic scoliosis

STUDY DESIGN

To review diagnosis and treatment of neurogenic factors implicated in the development of progressive scoliosis.

OBJECTIVE

Increased awareness of neurogenic causes as a contributing component of spinal cord tethering has led to enhanced radiographic surveillance for etiologic factors contributing to the genesis of scoliosis. Review of various manifestations of spinal dysraphism offers better definition of clinical indications for surveillance MRI scans and thus may contribute to improving outcomes for affected individuals.

SUMMARY OF BACKGROUND DATA

Increasing utilization of surveillance MRI has led to a greater awareness of neurogenic causes as contributing factors in the setting of scoliosis. It is imperative for clinicians treating individuals with scoliosis to be aware of the most common etiologies of neurogenic factors as well as be cognizant of the neurosurgical approaches to treating these conditions in a pre-emptive fashion. This will serve to minimize potential neurological complications and offer improved surgical outcomes after instrumentation.

METHODS

Current therapeutic approaches were outlined for various etiologies of neurogenic scoliosis as well as neurosurgical management of the tethered cord, spinal cord tumors in addition to current challenges surrounding Chiari malformations and syringomyelia.

RESULTS

Timely recognition of these frequently progressive conditions may not only prevent irreversible neurologic compromise but may also help to ameliorate or stabilize concurrent scoliosis. Tethered cords are best treated by releasing the affected cord and offers the best opportunity to stabilize or improve the scoliosis. Syringomyelia, often associated with a Chiari malformation, is a well-known progenitor of scoliosis, and addressing the underlying cause with a Chiari decompression frequently leads to a reduction or resolution of the syrinx and may result in a concomitant improvement in scoliosis.

CONCLUSION

Surveillance MRI should be undertaken for scoliosis when there are clinical indications consistent for a tethered cord, spinal cord tumor, or Chiari malformation and associated syringomyelia.

Posterior fossa dimension and volume estimates in pediatric patients with Chiari I malformations

INTRODUCTION

Chiari I malformations (CMI) involve pathological hindbrain abnormalities reported to be correlated with a hypoplastic posterior fossa. CMI was traditionally characterized by the downward herniation of the cerebellar tonsils with a descent of 5 mm or more below the foramen magnum. The fullness of the cisterna magna and CSF flow at the level of the cervicomedullary junction have been shown to be more useful in selecting symptomatic patients for surgical decompression. The present study calculates posterior fossa dimension and volume estimates in pediatric patients using magnetic resonance imaging. The combination of neuroradiological and clinical findings is used to re-examine the criteria used for diagnosis and treatment of pediatric CMI patients.

MATERIALS AND METHODS

A retrospective chart review was conducted on patients who were admitted to the Division of Neurosurgery of the Children's hospital of Eastern Ontario between 1990 and 2007. Clinical and radiological assessments were performed on all patients. Posterior fossa volumes (PFV) and intracranial volumes (ICV) were measured from sagittal head magnetic resonance imaging scans using the Cavalieri method.

RESULTS

Sixty-one CMI patients were identified. There were 32 male and 29 female patients with a mean age of 10 years (range: 8 weeks-18 years). Thirty-four (55%) of these patients were symptomatic with scoliosis (38%), suboccipital headaches (29%), and motor/sensory deficits (26%) being the most prominent symptoms. The mean PFV/ICV ratio for all the CMI patients (0.110) was found to be statistically smaller than that of the control patients (0.127, p=0.022). Mean PFV/ICV ratios for asymptomatic and symptomatic CMI patients were found to be similar for children aged 0-9 years (p=0.783) but different for children aged 10-18 years (p=0.018).

DISCUSSION

Mean PFV values were found to be smaller in pediatric CMI patients than control patients; this complements earlier studies in adults and supports the present theory concerning the pathophysiological mechanism of CMI. Subtle morphometric differences among asymptomatic and symptomatic patients aged 0-9 years stress the importance of monitoring asymptomatic patients for the onset of symptoms in their adult years. Symptom development in CMI is likely multifactorial and is much more extensive than the degree of cerebellar tonsillar herniation.

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.

Urgent surgical intervention in pediatric patients with Chiari malformation type I. Report of two cases

Patients with Chiari malformation Type I (CM-I) most commonly present with chronic symptoms. A search of the current medical literature revealed scant information regarding acute presentations of CM-I in either pediatric or adult patients. The authors report on two children who presented with rapidly worsening neurological symptoms attributable to a previously undiagnosed CM-I. One patient became profoundly hypopneic with dysphagia and right hemiparesis over a less than 48-hour period. The second patient presented with a few days of worsening right hemiparesis, gait disturbance, and anisocoria. In addition to a CM-I, magnetic resonance imaging in the second patient revealed a holocord syrinx. Following urgent posterior fossa decompression, both patients rapidly improved in the 24 hours immediately following surgery and continued to improve in the subsequent weeks. Few reports detail acute symptoms due to CM-I and those that do exist almost exclusively involve adult patients. Although seemingly rare, the clinician should consider CM-I in the differential diagnosis in pediatric patients presenting with acute brainstem or long tract signs.

Relevance of surgical strategies for the management of pediatric Chiari type I malformation

OBJECTIVE

In face of continuing controversy to the optimal treatment of Chiari type I malformation, the authors analyzed three different surgical strategies.

MATERIALS AND METHODS

Sixty patients (30 boys and 30 girls, mean age 8.2 years) presented with clinical Chiari malformation. Additional syringomyelia was present in 24 children, whereas cine flow studies showed no flow in the craniocervical junction in 48 children. All patients underwent a limited occipital craniectomy; a duraplasty was performed in 21 cases; and additional tonsillar reduction was performed in 19 cases. Clinical improvement was seen in 24 patients who underwent posterior decompression with or without duraplasty. In the tonsillar group, clinical improvement was evident in 18 patients.

CONCLUSIONS

Duraplasty and tonsillar reduction were equally effective but significantly better than bone decompression alone. Among patients with syringomyelia, tonsillar reduction was associated with a significantly better outcome. Postoperative flow studies improved in 39 patients but did not correlate to the clinical outcome.

Posterior Cranial Fossa Box Expansion Leads to Resolution of Symptomatic Cerebellar Ptosis Following Chiari I Malformation Repair

Chiari I malformation occurs when the cerebellar tonsils herniate downward through the foramen magnum into the upper cervical spinal canal. If the posterior fossa craniectomy during corrective surgery leads to excessive enlargement of the foramen magnum, the complication of cerebellar ptosis may result. To treat this difficult problem a posterior cranial fossa box expansion was devised and studied. Patients who developed symptomatic cerebellar ptosis (confirmed by MRI) following cranial vault decompression for Chiari I malformations underwent a posterior fossa box expansion (n=7). This procedure involved coverage of posterior aspect of the enlarged foramen magnum with a split-thickness calvarial bone graft box. The box reconstruction provided separation between the neck musculature, soft tissues from the neural tissue; prevention of cerebellar prolapse; and expansion of the posterior cranial vault. Patients had a mean of 12+/-1 months between initial suboccipital craniectomy and confirmation of symptomatic cerebellar ptosis. Mean age at the time of posterior fossa box reconstruction was 31+/-9 years (range of 14 to 44 years). Preoperative symptoms of headache (7/7, 100%), upper extremity numbness (5/7, 71%) or paresthesias (3/7, 43%), respiratory disturbance (2/7, 29%) and inability to walk (2/7, 29%) improved in all patients postoperatively. At more than 12 month follow-up 6/7 patients (86%) were both disease-free (MRI confirmation) and symptom-free. One out of seven patients had return of headache in a more mild form. Thus, in our patient group the posterior fossa box reconstruction led to resolution of symptomatic cerebellar ptosis following Chiari I malformation repair.

Acute presentation of hydromyelia in a child

The authors document a rapid development, within 3 weeks, of hydromyelia in a 12 year-old boy. The boy was admitted to a local hospital because of drowsiness and persistent severe neck pain. Neurological examination disclosed a lethargic boy with no neurological deficit other than Parinaud's sign. During his transfer to our department, he presented a cardio-respiratory arrest with coma and bilateral mydriasis. External ventricular drain and craniocervical decompression achieved excellent clinical and neuroradiological outcomes. The development of hydromyelia in this case is caused by obstruction to the natural cerebrospinal fluid pathway at the craniocervical junction and the cardio-respiratory arrest is provoked by a brain stem compression against the clivus and odontoid process. This report illustrates that hydromyelia may complicate acute obstructive hydrocephalus due to acquired Chiari malformation.