Considerations in the diagnosis and treatment of syringomyelia and the Chiari malformation

Surgical Outcomes in Chiari 1 and Chiari 1.5 Malformation Treated by Posterior Fossa Reconstruction: A Comprehensive Analysis of 110 Pediatric Cases and Literature Review

Background/Objectives: The management of Chiari malformations (CMs) remains a clinical challenge and a topic of great controversy. Results may vary between children and adults. The purpose of the current single-center study is to critically assess the one-year surgical outcomes of a cohort of 110 children with CM-1 or CM-1.5 who were treated using "posterior fossa reconstruction" (PFR), a surgical technique described in 1994 that has since been used in both adults and children. We also review the literature and discuss the possible causes of the drawbacks and pitfalls in children in whom PFR was ineffective in controlling the disease. Methods: The present cohort was selected from a prospective registry of adults and children with CMs collected since 2006. Patients included in this study were selected from a group of children with CMs who were operated on in our Pediatric Neurosurgical Unit between 1 January 2007 and 31 November 2023. Surgical outcome was defined based on clinical and neuroradiological results as very good, good, or bad. Results: The mean age of our child cohort was 9.9 ± 4.7 years, with 54 girls (49%) and 56 boys (51%). Sixty-six children had CM-1 (60%) while forty-four had CM-1.5 (40%). Following surgery, there was no neurological worsening or death among the children. Most children (70%) had an uneventful recovery and were discharged home on average one week after surgery. However, in 33 children (30%), we recorded at least one postoperative adverse event. Aseptic meningitis syndrome was the most frequent adverse event (n = 25, 22.7%). The final surgical outcome was evaluated one year after PFR by using both clinical and neuroradiological results. The one-year surgical outcome was excellent in 101 children (91.9%), good in 5 (4.5%), and bad in 4 (3.6%). Conclusions: PFR significantly enlarges the volume of the posterior fossa and recreates a CSF environment that generates buoyancy of the cerebellum, with a high percentage of excellent and good clinical results evaluated one year post-surgery.

Effectiveness of C1 Laminectomy for Chiari Malformation Type 1: Posterior Fossa Volume Expansion and Syrinx-Volume Decrease Rate

PURPOSE

This study aimed to analyze the effect of foramen magnum decompression with C1 laminectomy (C1L) for Chiari malformation type 1 (CM-1) in terms of improving clinical symptoms, expanding posterior fossa volume, and decreasing syrinx volume.

MATERIALS AND METHODS

Between January 2007 and June 2019, 107 patients with CM-1 were included. The median patient age was 13±13 years (range: 9 months-60 years), female-to-male ratio was 1:1, and average length of tonsil herniation was 13±5 mm (range: 5-24 mm). Surgical techniques were divided into four groups based on duraplasty or C1L usage. Among the study subjects, 38 patients underwent duraplasty and had their syrinx volumes measured separately on serial magnetic resonance imaging. A three-dimensional visualization software was used to evaluate the syrinx-volume decrease rate.

RESULTS

Bony decompression exhibited a mere 20% volume expansion of the lower-half posterior fossa. C1L offered a 3% additional volume expansion, which rose to 5% when duraplasty was added (p=0.029). There were no significant differences in complication rate when C1L was combined with duraplasty (p=0.526). Syrinx volumes were analyzed in 38 patients who had undergone duraplasty. Among them, 28 patients who had undergone duraplasty without C1L demonstrated a 5.9% monthly decrease in syrinx volume, which was 7.5% in the remaining 10 patients with C1L (p=0.040).

CONCLUSION

C1L was effective in increasing posterior fossa volume expansion, both with and without duraplasty. A more rapid decrease in syrinx volume occurred when C1L was combined with duraplasty.

Pediatric Chiari I malformation: novel and traditional measurements associated with syrinx and surgery

PURPOSE

Multiple imaging parameters have been examined to estimate the presence of syrinx and the need for surgery in Chiari I patients (CM1); however, no consistent or definitive criteria have been proposed. The objective of this study was to review existing and identify novel radiological and clinical characteristics of CM1 patients that associate syrinx development and surgical intervention.

METHODS

Patients with Chiari I malformation diagnosed on imaging between 0 and 18 years were retrospectively reviewed from January 1, 2007 to February 12, 2020. Participants were included if they had a baseline MRI of the head and spine prior to surgical intervention if required. Forty age-matched controls with cranial imaging were identified for comparison. Imaging parameters and clinical symptoms were recorded.

RESULTS

A total of 122 CM1 patients were included in this study. Of the 122 patients, 28 (23%) had syrinx, and 27 (22%) had surgery. The following imaging parameters associated with syrinx and surgical intervention were identified: midbrain length (P < 0.001; P = 0.032), the obex position (P = 0.002; P < 0.001) and medullary kinking (P = 0.041; P < 0.001). Among the clinical features, the presence of overall pain (P = 0.017; P = 0.042), neck pain (P = 0.005; P = 0.027), and sensory dysfunction (P < 0.001) were found to be strongly associated with syrinx and surgery.

CONCLUSION

While further investigation is needed, these specific radiological and clinical parameters should be considered when evaluating CM1 patients and may be used to guide further management.

Assessment of patients with a Chiari malformation type I

Introduction

The prevalence of Chiari malformation type I (CM-I) has been estimated as up to 1% of the general population. The majority of patients are asymptomatic and usually do not need treatment. Symptomatic patients, and some asymptomatic patients with associated conditions, may benefit from further assessment and treatment.

Research question

The aim of this review was to describe the clinical and radiological assessment of patients presenting with a CM-I.

Material and methods

A literature search was performed using the PubMed and Embase databases focused on clinical assessment and imaging techniques used to diagnose CM-I.

Results

Following a complete clinical evaluation in patients with symptomatic CM-I and/or radiologically significant CM-I (tonsillar impaction, resulting tonsillar asymmetry and loss of CSF spaces), MRI of the brain and whole spine enables an assessment of the CM-I and potential associated or causative conditions. These include hydrocephalus, syringomyelia, spinal dysraphism, and tethered cord. Flow and Cine MRI can provide information on CSF dynamics at the craniocervical junction, and help in surgical decision-making. Hypermobility or instability at the upper cervical and craniocervical junction is less common and can be measured with CT imaging and flexion/extension or upright MRI.

Discussion and conclusion

The majority of CM-I detected are incidental findings on MRI imaging of brain or spine, and do not require intervention. Once a radiological diagnosis and concern has been raised, clinical assessment by an appropriate specialist is required. A MRI brain and cervical spine is indicated in all radiologically labelled CM-I. In symptomatic patients or cases of radiologically significant CM-I, MRI of the brain and entire spine is indicated. Further investigations should be tailored to individuals’ needs.

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A CM-I assessment should include a history and examination and a referral to a specialist.

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MRI of the brain and spine enables an assessment of the CM-I and potential associated conditions.

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Flow and Cine MRI can help in surgical decision-making.

Complete posterior cranial vault distraction osteogenesis to correct Chiari malformation type I associated with craniosynostosis

OBJECTIVE

Posterior vault distraction osteogenesis (PVDO) is an effective tool to increase intracranial volume and expand the posterior cranial fossa. During PVDO, the authors extended osteotomy posterior to the foramen magnum to fully expand the posterior cranial fossa. The aim of this study was to investigate the efficacy of complete PVDO in posterior fossa expansion and treatment of Chiari malformation type I (CM-I) in patients with craniosynostosis.

METHODS

Patients with craniosynostosis who had undergone complete PVDO between January 2012 and May 2020 were reviewed retrospectively. A coronal osteotomy extending to the foramen magnum was performed and the foramen magnum was decompressed by removing its posterior rim with a 1-mm Kerrison rongeur. Four distractor devices were placed and the vector of distraction was controlled from the posterior to the inferior-posterior direction, depending on the deformity. Changes in the intracranial volume, posterior cranial fossa area, and cerebellar tonsillar descent were measured after complete PVDO by using CT and MRI.

RESULTS

A total of 11 patients with craniosynostosis and concurrent CM-I were included in the study. The mean age was 34.6 ± 24.0 months (continuous variables are expressed as the mean ± SD throughout). One patient had sleep apnea, which was consistent with CM-I, and another patient had a headache, which was nonspecific. The intracranial volume increased from 1179.6 ± 180.2 cm3 to 1440.6 ± 251.5 cm3 (p = 0.003; 24.5% increase compared to the preoperative volume). The posterior skull base area increased from 44.9 ± 19.3 cm2 to 72.7 ± 18.1 cm2 (p = 0.004). Cerebellar tonsillar descent decreased in all 11 patients after complete PVDO (preoperative: 10.8 ± 3.7 mm, postoperative: 2.7 ± 3.0 mm; p = 0.003). Among the 11 patients, 5 showed complete resolution of cerebellar tonsillar herniation.

CONCLUSIONS

Complete PVDO can more efficiently expand the posterior cranial fossa, unlike conventional methods. Moreover, it helps to relieve cerebellar tonsillar herniation. Complete PVDO is a powerful tool to increase the intracranial and posterior fossa volumes in patients with craniosynostosis and concurrent CM-I.

Long-term outcomes of surgical management in subtypes of Chiari malformation

Objective: Chiari malformations (CMs) are a heterogeneous group of disorders defined by anatomic anomalies of the cerebellum, brainstem, and craniovertebral junction (CVJ). The aims of this study are to establish the demographic and clinical features, incidence, surgical procedures, and outcomes in large series of old and new subtypes of CMs.Material and Methods: All patients were evaluated and operated on for CM-0, 1, and 1.5 between 1985 and 2016. The patients were grouped into various subtypes. Demographic data, additional diseases, clinical features, surgical procedures, complications and outcomes were recorded.Results: 191 patients who underwent various surgical procedures were evaluated. Their mean age was 37.21 ± 9.89. We detected 15 cases of CM-0 (7.8%), 121 cases of CM-1 (63.4%), 55 cases of CM-1.5 (28.8%). In total there were 191 cases, and 220 surgical procedures were performed. 29 (13.2%) of all surgical procedure was reoperations and secondary operations. SM Cyst is found to be decreased in 72 (76.5%) patients, unchanged in 14 (14.8%) and increased in 8(8.5%) of 94 patients radiologically. Clinical outcomes are better for 131 (65.8%), same for 31 (16.2%) and worse for 9 (15%).Conclusion: This study with 172 patients is a large series that includes CM-0, 1, and 1.5 subtypes. CM-1.5 also differs for symptom presentation and durations from CM-1. There are more neurological abnormalities in patients with SM. CVD alone are an effective, useful and safe surgical procedure for CM-0, CM-1 and CM-1.5. Surgical procedure, SM existence, and symptom duration have powerful effects on outcomes.

Posterior Fossa Decompression and superficial durotomy rather than complete durotomy and duraplasty in the management of Chiari 1

Objective: We aimed to evaluate the effectiveness and reliability of posterior fossa decompression (PFD) and superficial durotomy in patients who underwent surgery for Chiari malformation type 1 (CM1).Materials and Methods: Our study included 54 patients with the diagnosis of CM1 who had surgery between January 2012 and June 2019. The patients were divided into two groups according to the surgical technique applied. Group 1 included 10 patients who underwent classic PFD and duraplasty, and Group 2 included 44 patients who underwent PFD and superficial durotomy surgery. Pre- and postoperative clinical signs and symptoms of each patient were recorded. Simultaneously, morphometric measurements were compared from computed tomography (CT) and magnetic resonance (MRI) images taken pre- and postoperatively. The data of the two groups were compared.Results: Of the 54 patients, 18 were male, and the mean age was 37.51 ± 15.14. A statistically significant difference was found between the pre- and postoperative morphometric measurements of the subarachnoid distance, craniocervical angle, syringomyelia, and hydrocephalus at the cerebellum level in Group 2 patients who underwent PFD and superficial durotomy surgery (p < 0.05). When morphometric measurements and clinical signs and symptoms of both groups were compared, no significant difference was found (p > 0.05). There was a 92% improvement in clinical signs and symptoms postoperatively. The complications seen in Group 1 decreased to a minimum in Group 2.Conclusion: We believe that a minimally invasive surgical method is superior to avoid major complications. We also found PFD and superficial durotomy shorten the duration of the patient's hospital stayAbbreviations: C1: cervical vertebra 1C2: cervical vertebra 2CM: Chiari malformationCM1: Chiari malformation type 1CSF: cerebrospinal fluidCT: computed tomographyMRI: magnetic resonance imagingPFD: posterior fossa decompressionUSG: ultrasonography.

Atypical Presentation of Chiari I Malformation in a 13-Year-Old Adolescent

In this report, we describe a 13-year-old with opisthotonos as the presenting symptom of Chiari I malformation. This presentation is rare and has previously been reported only in infants. We describe the physical and radiologic findings, literature regarding Chiari malformation, and differential diagnosis of opisthotonos in this patient.

Sequential Enlargement of Posterior Fossa After Duraplasty for Chiari Malformation Type 1

Objective

There are several material options for duraplasty in surgery for foramen magnum decompression (FMD). We retrospectively analyzed surgical results and the impact of sequential alteration of posterior fossa (PF) size in patients with Chiari malformation type 1 after duraplasty using local fascia.

Methods

The patients with Chiari malformation type 1 who underwent FMD with duraplasty using local fascia at our institution between 2004 and 2015 were included in the study. Some pediatric patients who underwent FMD without duraplasty and patients with insufficient follow-up data were excluded. Improvement of clinical signs, regression of syrinx, and temporal alteration of PF size were analyzed with perioperative magnetic resonance imaging. Postoperative clinical outcomes were evaluated at the final follow-up using the Chicago Chiari Outcome Scale. Correlations between the PF size alteration and size of dural patch or Chicago Chiari Outcome Scale were statistically analyzed.

Results

Twelve patients were included in this study. The mean age of the patients was 31.9 (range, 18–48) years. Syrinx was incorporated in 11 patients and regressed postoperatively in all patients. The PF was significantly enlarged sequentially over time (P < 0.05). The degree of enlargement was positively correlated with size of the fascial patch (r = 0.540). Postoperative clinical outcomes at final follow-up were positively correlated with the degree of PF enlargement (r = 0.678).

Conclusions

The PF was enlarged sequentially over time after duraplasty using local fascia. The degree of enlargement was positively correlated with the size of the fascial patch and the likelihood of a favorable postoperative outcome.

Surgical Treatment of Chiari Malformation in Adults: Comparison of Surgical Techniques Described in the Literature and Our Experience

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Management of parturients in active labor with Arnold Chiari malformation, tonsillar herniation, and syringomyelia

BACKGROUND

Arnold-Chiari malformation Type 1 (ACM-1) in parturients is a topic of ongoing discussion between obstetricians and anesthesiologists. The primary unanswered question remains; How should the anesthesia provider proceed with labor analgesia and anesthesia for cesarean section when confronted with an advanced, asymptomatic, or minimally symptomatic case of ACM-1 during labor?

CASE DESCRIPTION

A 24-year-old, ASA II, G1P0 full-term parturient presented to Labor and Delivery for vaginal delivery. A diagnosis of ACM-1 was made 12 years ago when a brain magnetic resonance imaging (MRI) was performed for right-sided numbness following a rear-end motor vehicle collision. The patient had been asymptomatic since then and had been seen by an outside neurologist frequently for the past 10 years. During the anesthesia evaluation, it was noted that she had an exaggerated patellar reflex, and a questionable left-sided Babinski; subsequently, an MRI study was requested. Review of a brain MRI demonstrated an advanced form of ACM with a 1.7 cm transtonsillar herniation and a large syrinx extending from C1 down to C5. Following a discussion with the patient, family, and primary OB team, a plan for elective cesarean section was made per neurosurgical recommendations. This was conducted uneventfully under general anesthesia. The patient had no complaints in the post-anesthesia care unit.

CONCLUSION

Unfamiliarity of health care providers with regards to ACM-1 parturients can be countered by increasing awareness of this condition throughout medical specialties involved in their care. The Ghaly Obstetric Guide to Arnold-Chiari malformation Type 1, along with proper training of anesthesia care providers regarding the specificities of ACM-1 parturients aids in better management and understanding of this complex condition.

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%).

Foramen Magnum Decompression and Duraplasty is Superior to Only Foramen Magnum Decompression in Chiari Malformation Type 1 Associated with Syringomyelia in Adults

STUDY DESIGN

Retrospective cohort study.

PURPOSE

To compare surgical results of foramen magnum decompression with and without duraplasty in Chiari malformation type 1 (CM-1) associated syringomyelia (SM).

OVERVIEW OF LITERATURE

The optimal surgical treatment of CM-1 associated with SM is unclear.

METHODS

Twenty-five cases of CM-1 with SM were included. There were 12 patients (48%) in the non-duraplasty group and 13 patients (52%) in the duraplasty group. The rate of improvement, state of postoperative SM size, amount of tonsillar herniation, preoperative symptom duration, complications and reoperation rates were analysed.

RESULTS

The rate of clinical improvement was significantly higher with duraplasty (84.6%) than without (33.3%, p <0.05). The rate of postoperative syrinx regression was significantly higher in the duraplasty group (84.6%) than in the non-duraplasty group (33.3%, p <0.05). One case in the duraplasty group needed a reoperation compared with five cases in the non-duraplasty group (p =0.059).

CONCLUSIONS

Duraplasty is superior to non-duraplasty in CM-1 associated with SM despite a slightly higher complication rate.

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.

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.

Association of increased body mass index with Chiari malformation Type I and syrinx formation in adults

Object

In this paper the authors describe an association between increased body mass index (BMI) and Chiari malformation Type I (CM-I) in adults, as well as its relationship to the development of syringomyelia.

Methods

In the period between January 2004 and December 2011, the senior author reviewed the data for all CM-I patients with or without syringomyelia and neurological deficit. Analyzed factors included clinical status (headaches and neurological signs), radiological characteristics of syringomyelia (diameter and vertical extent of syrinx), BMI, and relationship of age to BMI, syrinx diameter, and vertical extent of syrinx.

Results

Sixty consecutive adults had CM-I, 26 of whom also had syringomyelia. The mean BMI among all patients was 30.35 ± 7.65, which is Class I obesity (WHO), and was similar among patients with or without syringomyelia. Extension of the vertical syrinx was greater in overweight patients (p = 0.027) than in those with a normal body weight. Evidence of de novo syrinx formation was found in 2 patients who gained an average BMI of 10.8 points. After repeated decompression and no change in holocord syrinx width or vertical extent, a reduction in the syrinx was seen after BMI decreased 11.7 points in one individual. No correlation was found between patient age and BMI, age and vertical extension of the syrinx, and age and diameter of the syrinx.

Conclusions

An association between increased BMI and CM-I in adults was recognized. Gaining weight may influence the de novo creation of a syrinx in adults who previously had minimally symptomatic or asymptomatic CM-I, and reducing weight can improve a syrinx after unsuccessful surgical decompression. Therefore, a reduction in body weight should be recommended for all overweight and obese patients with CM-I.

Perioperative outcomes and complications associated with allogeneic duraplasty for the management of Chiari malformations Type I in 48 pediatric patients

OBJECT

The authors debate the optimal management for Chiari malformation Type I (CM-I) while sharing their experience with posterior fossa decompression and duraplasty (PFDD).

METHODS

The charts of 48 consecutive pediatric patients surgically treated for CM-I were retrospectively reviewed.

RESULTS

Patients ranged in age from 2 to 17 years with an average age of 9.8 years. The most common presentations were headache, affecting 34 patients (71%), and pain (neck, back, or extremities), affecting 21 patients (44%). Twenty-seven patients (56%) had a syrinx. All 48 patients underwent PFDD utilizing acellular tissue matrix. The average hospital stay overall was 3.56 days, whereas the average stay for patients with (29 [60%] of 48) or without (19 [40%] of 48) scoliosis and/or syringomyelia was 3.72 and 3.32 days, respectively. The odds of a patient having a hospital stay of 4 or more days was nearly 3 times greater in patients with scoliosis and/or syringomyelia as compared with patients without either condition (OR 2.73, 95% CI 0.74-10.11, p = 0.1330). The average hospital stay for patients 0-8 years of age was 3.29 days; and for those 9-17 years of age, 3.78 days. The odds of a patient having a hospital stay of 4 or more days was nearly 4 times greater in 9- to 17-year-olds as compared with 0- to 8-year-olds (OR 3.73, 95% CI 1.03-13.52, p = 0.0455). Forty patients (89%) experienced early improvement in their signs and symptoms following PFDD. There were 2 revision PFDDs (4%).

CONCLUSIONS

Posterior fossa decompression and duraplasty is a safe and effective surgical option in the management of pediatric CM-I.

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.

Scoliosis and Chiari malformation Type I in children

OBJECT

The identification of Chiari malformations Type I (CM-Is) has increased in recent years, commonly during MR imaging for evaluation of a possible cause of scoliosis. The treatment of this abnormality remains controversial, and the expected success of treatment is unclear. The goal of the present study is to evaluate the effects of a craniotomy for CM-I decompression on scoliosis in children and adolescents.

METHODS

The authors conducted a 10-year retrospective review of pediatric patients who were found to have a CM-I during evaluation for scoliosis. Seventy-nine patients were identified, ranging in age from 6 months to 18 years (median 12 years). There were 42 girls (54%) and 37 boys (46%). All were noted on MR imaging to have hydrosyringomyelia of the spinal cord. Forty-nine patients had curvatures less than 20° prior to treatment. The other 30 patients had curves ranging from 25° to 80° and underwent orthopedic follow-up and treatment. None of these patients were referred for specific neurological complaints, but 12 (16%) had neurological signs on physical examination. All were treated with a craniocervical decompression in a standard fashion. Follow-up ranged from 6 to 93 months with a median of 35 months. Magnetic resonance images obtained at 6 months postoperatively and serial standing anteroposterior spine radiographs were used to evaluate outcomes.

RESULTS

On the MR images obtained 6 months postoperatively, 70 patients (89%) had a significant reduction in the syrinx with an associated ascent of the cerebellar tonsils. Persistent large syringes were treated with reoperation in 6 patients, and shunts were inserted for hydrocephalus in 2 patients. None of the 49 patients with curves less than 20° had progression of their curvature postoperatively. Of the 30 patients with curves greater than 25°, 9 had no change in the scoliosis or had a reduction in curve magnitude after Chiari decompression. This group required no further therapy and was effectively treated by Chiari decompression alone. Twenty-one patients required further scoliosis treatment after Chiari decompression; 12 required orthotic treatment, 11 received spinal instrumentation and fusion surgery, and 2 received orthoses followed by fusion and instrumentation. The severity of the curvature beyond 20° did not predict the need for spinal surgery.

CONCLUSIONS

This large series reports on the efficacy of treatment for scoliosis associated with a CM-I and syrinx in children. A CM-I decompression alone was adequate treatment for mild scoliosis of less than 20°. Patients with scoliosis greater than 20° required bracing and/or spinal fusion surgery 70% of the time in addition to the CM-I decompression.

Preysyrinx state and shunt dysfunction: an underrecognized entity?

Presyrinx state is a relatively recently recognized condition. Prompt identification of this condition and appropriate treatment leads to reversal of the radiological and clinical findings with a good prognosis. Failure to identify this condition in a timely fashion leads to fully established syringomyelia. To date, presyrinx state has not been described as a feature of shunt dysfunction. One such rare case is being reported. A 14-year-old boy who was shunted for postmeningitic hydrocephalus at the age of 2 years and subsequently underwent shunt revision presented for routine follow-up and was found to have shunt dysfunction. CT scan showed panventriculomegaly and MRI studies showed panventriculomegaly with a "presyrinx" state extending from the fourth ventricle up to the thoracic region. Shunt revision led to prompt radiological reversal of the presyrinx state. This case is being reported to highlight the hitherto unreported association of shunt dysfunction and presyrinx state. The literature on presyrinx state is being reviewed with reference to the 20 cases reported earlier.

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.

Pathogenesis of syringomyelia associated with Chiari type 1 malformation: review of evidences and proposal of a new hypothesis

The exact pathogenesis of syringomyelia associated with Chiari type 1 malformation is unknown, although a number of authors have reported their theories of syrinx formation. The purpose of this review is to understand evidences based on the known theories and to create a new hypothesis of the pathogenesis. We critically review the literatures on clinicopathological, radiological, and clinical features of this disorder. The previously proposed theories mainly focused on the driven mechanisms of the cerebrospinal fluid (CSF) into the spinal cord. They did not fully explain radiological features or effects of surgical treatment such as shunting procedures. Common findings of the syrinx in clinicopathological studies were the communication with the central canal and extracanalicular extension to the posterior gray matter. Most of the magnetic resonance imaging studies demonstrated blockade and alternated CSF dynamics at the foramen magnum, but failed to show direct communication of the syrinx with the CSF spaces. Pressure studies revealed almost identical intrasyrinx pressure to the subarachnoid space and decreased compliance of the spinal CSF space. Recent imaging studies suggest that the extracellular fluid accumulation may play an important role. The review of evidences promotes a new hypothesis of syrinx formation. Decreased absorption mechanisms of the extracellular fluid may underlie the pathogenesis of syringomyelia. Reduced compliance of the posterior spinal veins associated with the decreased compliance of the spinal subarachnoid space will result in disturbed absorption of the extracellular fluid through the intramedullary venous channels and formation of syringomyelia.

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.

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

Background

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

Methods

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

Results

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

Conclusion

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

Suboccipital decompression for Chiari I malformation: outcome comparison of duraplasty with expanded polytetrafluoroethylene dural substitute versus pericranial autograft

OBJECTIVE

Treatment failure for Chiari decompression is frequently associated with scarring, intradural adhesions, and recurrent loss of hindbrain space. While autograft has been our standard for hindbrain duraplasty, we investigated whether introducing anti-adhesive synthetic GORE PRECLUDE MVP Dura Substitute (expanded polytetrafluoroethylene [ePTFE] graft) was associated with improved patient outcomes.

MATERIALS AND METHODS

We retrospectively reviewed records of patients undergoing first-time suboccipital decompression/duraplasty for Chiari-I malformation utilizing ePTFE graft or pericranial autograft. Magnetic resonance imaging (MRI) at last follow-up was assessed for: (1) recurrent loss of dorsal hindbrain cerebrospinal fluid (CSF) space/CSF flow(cine-MR) at duraplasty site, (2) pseudomeningocele, or (3) syringomyelia improvement. Symptom recurrence warranting revision surgery was compared between cohorts.

RESULTS

Sixty-seven patients (age 11 +/- 5 years) underwent duraplasty with pericranial autograft (n = 40) or ePTFE graft (n = 27). Perioperative morbidity did not differ between cohorts. No patients receiving ePTFE graft experienced incisional CSF leak, surgical site infection, or symptomatic pseudomeningocele. At median 8 months postoperatively, all (100%) patients with ePTFE graft maintained physiological CSF flow/decompressed hindbrain CSF space on cine-MRI versus 32 (79%) patients receiving pericranial autograft (p < 0.05). Radiographic syrinx improvement occurred in 80% of patients with ePTFE graft and 52% of patients with pericranial autograft (median time to improvement: 5 vs 12 months, respectively, p < 0.05). At median 16 months postoperatively, four (10%) patients with pericranial autograft required revision decompression versus 0 (0%) patients with ePTFE graft (p = 0.090).

CONCLUSION

Duraplasty utilizing ePTFE graft was associated with improved maintenance of hindbrain space, accelerated syringomyelia improvement, and a trend toward decreased treatment failure versus pericranial autograft. Future studies of long-term outcome are warranted to confirm observed effects. Synthetic ePTFE graft is a safe alternative for duraplasty in the setting of Chiari malformation.

Symptom recurrence after suboccipital decompression for pediatric Chiari I malformation: analysis of 256 consecutive cases

OBJECTIVE

Symptom recurrence remains a problem for some patients after surgical decompression for Chiari I malformation. We set out to identify variables at presentation that could identify subgroups most likely to experience incomplete symptom relief after hindbrain decompression for Chiari I malformation.

MATERIALS AND METHODS

We retrospectively reviewed the records of all pediatric patients undergoing first-time suboccipital decompression for Chiari I malformation over a 10-year period. Measured outcomes included (1) persistence or recurrence of symptoms regardless of severity and (2) need for revision decompression.

RESULTS

Two hundred fifty-six children (10 5 years old) underwent surgery for Chiari I malformation and were followed up for a mean of 27 months. Presenting symptoms included headache in 192 (75%) patients and brainstem or cranial nerve symptoms in 68 (27%) patients. Fifty-seven (22%) patients experienced mild to moderate symptom recurrence. Nineteen (7%) patients required revision decompression for significant symptom recurrence. Headache was 70% more likely to persist or recur versus cranial nerve or brainstem symptoms (relative risk 1.70, p < 0.05). Vertigo and frontal headache independently increased the odds of symptom recurrence 2.9- and 1.5-fold, respectively. Each increasing year of preoperative headache duration was independently associated with 15% increase in likelihood of symptom persistence (p < 0.05). Severe tonsilar ectopia (caudal to C2 lamina) was twice as likely to require revision decompression (14% versus 6%).

CONCLUSION

In our experience, recurrence of mild symptomatology not severe enough to justify revision surgery may occur in nearly a fifth of patients after surgery. Headache was more likely to recur than objective cranial nerve or brainstem symptoms. Increasing duration of headaches, frontal headaches, and vertigo may be more refractory symptoms of Chiari I malformation.

Spontaneous resolution of syringomyelia without Chiari malformation

A 30-year-old woman presented with a cervical syrinx manifesting as hemihypesthesia. Neuroimaging found no evidence of Chiari malformation or tight cisterna magna. Serial magnetic resonance imaging studies over a 6-year period demonstrated spontaneous and complete resolution of the syrinx accompanied by an asymptomatic clinical course. The natural history of syringomyelia is highly unpredictable. The outcome of surgical treatment for patients with syringomyelia is not always satisfactory, so the indications for surgery are controversial. Spontaneous resolution of syringomyelia unrelated with foramen magnum lesion has various causes. Close follow up of the patient is necessary to monitor for recurrence.

Relationship of cine phase-contrast magnetic resonance imaging with outcome after decompression for Chiari I malformations

OBJECTIVE

Many patients with symptomatic Chiari I malformations experience symptom recurrence after surgical decompression. Identification of predictors of outcome is needed to better select patients most likely to benefit from surgical intervention. We examined whether or not cerebrospinal fluid (CSF) flow dynamics assessed by cine phase contrast magnetic resonance imaging could independently predict response to posterior fossa decompression for Chiari I malformations.

METHODS

Pre- and postoperative CSF flow dynamics were assessed by cine phase-contrast magnetic resonance imaging in 130 consecutive patients receiving posterior fossa decompression for a Chiari I malformation between 1997 and 2003. CSF flow was classified as "abnormal" if biphasic flow was either absent or decreased through the aqueduct, fourth ventricle and its outlets, the foramen magnum, or ventral or dorsal to the cervical spinal cord. If no evidence of decreased flow was noted, CSF flow was classified as "normal." The association between preoperative CSF flow dynamics, all recorded variables, and long-term outcome was assessed using multivariate proportional hazards regression analysis.

RESULTS

All patients had tonsil herniation more than 5 mm below the foramen magnum (average, 11 +/- 5 mm). Abnormal hindbrain CSF flow was observed in 81% of patients (43% complete obstruction, 38% reduced flow). Normal CSF flow was observed in 19% of patients. In multivariate analysis, patients with normal preoperative hindbrain CSF flow were 4.8-fold more likely to experience symptom recurrence after surgery (relative risk, 4.85; 95% confidence interval, 1.88-12.5; P < 0.001) regardless of degree of tonsillar ectopia or presence of syringomyelia. Isolated frontal headache (relative risk, 4.16; 95% confidence interval, 1.7-9.8; P < 0.05) and scoliosis (relative risk, 9.2; 95% confidence interval, 1.7-10.5; P < 0.001) also were independent risk factors for symptom recurrence.

CONCLUSION

Normal preoperative hindbrain CSF flow was an independent risk factor for treatment failure after decompression for Chiari I malformation regardless of the degree of tonsillar ectopia. Cine phase-contrast magnetic resonance imaging may be a valuable tool in identifying patients who are less likely to respond to surgical decompression for Chiari I malformation.

A modified technique for syringo-subarachnoid shunt for treatment of syringomyelia

Syringo-subarachnoid shunting is a well-established procedure for the treatment of syringomyelia. However, the standard surgical procedure requires a laminectomy and posterior midline myelotomy, which have potential complications. In this study, we describe our clinical experience with a modified technique for syringo-subarachnoid shunt insertion in eight patients between 1998 and 2002. The technique comprises a limited hemilaminectomy, a 2 mm myelotomy at the site of dorsal root entry zone, introduction of a 1.5 mm thick catheter into the syrinx and placement of the distal tip of the catheter in the anterolateral subarachnoid space. Using this technique there was no operative morbidity or mortality. Collapse of the syrinx, in the first post-operative month, was demonstrated by MRI in all cases. There were no relapses in the follow-up period. Although our experience is limited and the results preliminary, this technique is less invasive than commonly used techniques and the results are favorable.

Adult Chiari malformation and sleep apnoea

Chiari malformation (CM) is primarily characterised by herniation of the cerebellar tonsils through the foramen magnum. Clinically, two main types of CM represent the vast majority of cases: type I (in adults) and type II (in infants). CM may result in neuronal impairment of the brainstem, upper spinal cord and cranial nerves. Part of the afferent and efferet systems and the central respiratory controlling system are located in the cranium-cervical transition and may be damaged in these pathologies, leading to respiratory disorders, such as respiratory failure and death. The ventilatory responses to exogenous and endogenous stimuli, such as responses to hypoxia and hypercapnia, are usually diminished, and apnea may be manifested and detected during sleep, allowing for the diagnosis. This study is a review of the relationship between sleep apnoea and adult CM.

Acute Idiopathic Syringomyelia: A Case Report

There have been isolated reports in the literature of the natural history and less than complete knowledge of the epidemiology and pathophysiology of syringomyelia. This article describes a clinically acute-onset abnormal patient with localized dilatation of the central canal of the spinal cord who had no evidence of present or prior Chiari's malformation, trauma, infection, tumor, or other predisposing pathologic condition. It is suggested that this distinct condition be labeled "acute idiopathic syringomyelia".

Surgical experience of syringomyelia with reference to the findings of magnetic resonance imaging

We present our surgical experience of 20 patients with syringomyelia, who were divided into two groups based on the findings of magnetic resonance (MR) imaging: a "non-visible cisterna magna" group, in which MR imaging did not reveal cerebrospinal fluid (CSF) in the cisterna magna, and a "visible cisterna magna" group. Patients with non-visible cisterna magna were associated with Chiari malformation (14 patients) or tight cisterna magna (4 patients) and underwent craniocervical decompression. Intradural exploration was performed when CSF movement in the cisterna magna or CSF outflow from the fourth ventricle appeared to be insufficient. It is important to confirm CSF outflow from the foramen of Magendie. Patients with visible cisterna magna were associated with tuberculous meningitis (2 patients) and underwent shunting procedures. Postoperatively, improvement in symptoms and a reduction in syrinx size were demonstrated in all patients except one. Two patients experienced recurrence of symptoms and syrinx dilatation.

Scoliosis associated with Chiari 1 malformations: the effect of suboccipital decompression on scoliosis curve progression: a preliminary study

STUDY DESIGN

A retrospective review of the effect of suboccipital decompression and duraplasty on curve progression in 22 patients who presented with scoliosis, syringomyelia, and a Chiari 1 malformation.

OBJECTIVES

To document the clinical characteristics of scoliosis in association with a Chiari 1 malformation, determine the effects of suboccipital decompression and duraplasty on scoliosis curve progression over time, and identify the clinical factors (age, gender, and curve characteristics) that may be associated with a clinical improvement in the scoliotic deformity after suboccipital decompression.

SUMMARY OF BACKGROUND DATA

Prior publications have documented the clinical characteristics, signs, and symptoms of the Chiari 1 malformation. An association between Chiari 1 malformations, syringomyelia, and scoliosis has been recognized and reported. Several authors have also reported on the response of the scoliotic curve to Chiari 1 decompression, but the number of patients in these reports has been small. This cohort represents the largest number of patients to date (21) with Chiari 1 malformations, syringomyelia, and scoliosis who have been treated and followed over time in order to determine the effect of decompression on curve progression.

METHODS

A retrospective case review of 85 patients, age 16 years or less, who underwent posterior fossa decompression for a Chiari 1 malformation between 1990 and November 2000. A subset of 7 males and 15 females (22 of 85 total patients) who initially presented with scoliosis and were then found to have a Chiari 1 malformation was selected from this larger cohort for further review. The orthopedic and neurosurgical charts, spinal radiographs, and magnetic resonance imaging scans were then reviewed for each of these patients.

RESULTS

Twenty-one of the 22 patients who presented with scoliosis met the inclusion criteria of having a Chiari 1 malformation, scoliosis, and an unfused spine during the follow-up period after suboccipital decompression. One patient had a posterior spinal fusion before suboccipital decompression and was excluded from further review.

CONCLUSIONS

Thirteen patients of the 21 study patients (62%) had curve improvement or stabilization during the follow-up period. Eight of 21 patients (38%) had curve progression. Closer analysis reveals that the age, gender, and initial size of the scoliotic curve influenced the results of suboccipital decompression on the behavior of the scoliosis. Specifically, 10 of 11 patients (91%) who were less than 10 years of age at the time of suboccipital decompression have had their curves improve or stay the same during follow-up. In contrast, 5 of 7 female patients (72%) older than 10 years old with a curve greater than 40 degrees before suboccipital decompression have either been fused or are awaiting fusion.

Post-traumatic syringomyelia: a review

More than a quarter of spinal cord injured patients develop syringes and many of these patients suffer progressive neurological deficits as a result of cyst enlargement. The mechanism of initial cyst formation and progressive enlargement are unknown, although arachnoiditis and persisting cord compression with disturbance of cerebrospinal fluid flow appear to be important aetiological factors. Current treatment options include correction of bony deformity, decompression of the spinal cord, division of adhesions, and shunting. Long-term improvement occurs in fewer than half of patients treated. Imaging evidence of a reduction in syrinx size following treatment does not guarantee symptomatic resolution or even prevention of further neurological loss. A better understanding of the causal mechanisms of syringomyelia is required to develop more effective therapy.

Syringomyelia without hindbrain herniation: tight cisterna magna. Report of four cases and a review of the literature

Idiopathic syringomyelia, which is not associated with any definite pathogenic lesions, has been treated mainly by shunting of the syrinx and rarely by craniocervical decompression. The authors report four cases of syringomyelia thought to be idiopathic syringomyelia but treated by craniocervical decompression with favorable results. Syringomyelia was present without hindbrain herniation. In such cases, the subarachnoid space anterior to the brainstem at the level of the foramen magnum is usually open but the cisterna magna is impacted by the tonsils, a condition the authors term "tight cisterna magna." All patients underwent foramen magnum decompression and C-1 laminectomy, and the outer layer of the dura was peeled off. Further intradural exploration was performed when outflow of cerebrospinal fluid (CSF) from the fourth ventricle was deemed to be insufficient. Postoperatively, improvement in symptoms and a reduction in syrinx size were demonstrated in three patients, and a reduction in ventricle size was shown in two. Syringomyelia associated with tight cisterna magna should not be classified as idiopathic syringomyelia; rather, it belongs to the category of organic syringomyelia such as Chiari malformation. A possible pathogenesis of cavitation is obstruction of the CSF outflow from the foramen of Magendie, and the cavity may be a communicating dilation of the central canal. Ventricular dilation may depend on the extent to which CSF drainage is impaired from the foramina of Luschka. These cavities may respond to craniocervical decompression if it results in sufficient CSF outflow from the foramen of Magendie, even in cases with concomitant hydrocephalus.

Adult scoliosis in syringomyelia associated with Chiari I malformation

STUDY DESIGN

In adult syringomyelia associated with Chiari I malformation, the spinal deformity, the configuration of cerebellar tonsillar descent, the configuration of syrinx, and the clinical evaluation before and after surgery were investigated.

OBJECTIVES

To investigate the characteristics of the scoliosis in syringomyelia associated with Chiari I malformation.

SUMMARY OF BACKGROUND DATA

In previous studies, the clinical characteristics of pediatric scoliosis associated with syringomyelia have been reported.

METHODS

In this study, 42 patients with syringomyelia were treated. All the patients were 20 years of age or older. They were divided into three groups: Group 1 comprising those without scoliosis, Group 2 composed of those with scoliosis of 10 degrees or more but less than 20 degrees, and Group 3 consisting of those with scoliosis of 20 degrees or more. Investigations conducted with the three groups included determining the curve patterns of scoliosis, the degree of thoracic kyphosis, the configuration of cerebellar tonsillar descent, the configuration of syrinx, the morbidity period, and the clinical evaluation before and after surgery.

RESULTS

There were 12 patients in Group 1, 21 patients in Group 2, and 9 patients in Group 3. The concomitant rate of adult syringomyelia with scoliosis was 71.4%. As scoliosis advanced, the kyphotic angle also increased. The concordance in laterality between the cerebellar tonsil and curve convex was 70%. Findings showed that the more advanced the scoliosis was, the more aggravated the neurologic symptoms were, and the poorer the surgical outcomes tended to be.

CONCLUSIONS

In adult syringomyelia with scoliosis, the morbidity period is long, the syrinx is long, the neurologic symptoms are aggravated, and the surgical outcomes tend to be poor.