Persistent/Recurrent syringomyelia after Chiari decompression-natural history and management strategies: a systematic review

Natural history of Chiari I malformation with syrinx and dilatation of the central canal in the pediatric population: the CHEO experience

PURPOSE

Given that syrinx is often considered an indication of surgery in children with Chiari I malformation (CM1), understanding of the natural history of these patients is very challenging. In this study, we investigate the natural history of children with CM1 that have syrinx and/or prominence of the central canal on presentation.

METHODS

All pediatric Chiari I patients who had syrinx and/or prominence of the central canal who underwent MR imaging of the head and spine from 2007 to 2020 were reviewed. Patients were divided into 3 groups (early surgery, delayed surgery, and conservative management). We focused on those patients who did not initially undergo surgery and had at least 1 year of clinical follow-up. We assessed if there were any radiological features that would correlate with need for delayed surgical intervention.

RESULTS

Thirty-seven patients met the inclusion criteria. Twenty-one patients were female and 16 were male. The mean age at presentation was 8.7 (5.8 SD). Fourteen (38%) patients had early surgical intervention, with a mean of 2.5 months after initial presentation, 8 (16%) had delayed surgery due to new or progressive neurological symptoms and 46% of patients did not require intervention during follow-up. The length of tonsillar herniation and the position of the obex were associated with the need of surgery in patients who were initially treated conservatively.

CONCLUSION

In pediatric patients with CM1 with syringomyelia and prominence of the central canal, conservative treatment is initially appropriate when symptoms are absent or mild. Close follow-up of patients with CM1 and dilatation of the central canal who have an obex position below the foramen magnum and greater tonsillar herniation is suggested, as these patients show a trend towards clinical deterioration over time and may require earlier surgical intervention.

Influence of affective disorders on outcomes after suboccipital decompression for adult Chiari I malformation

INTRODUCTION

Affective disorders (AD) have been shown to influence patient outcomes and healthcare resource utilization across several pathologies, though this relationship has not been described in patients with Chiari I malformations (CM-I). The aim of this study was to determine the impact of comorbid AD on postoperative events and healthcare resource utilization in adults following suboccipital decompression for CM-I.

METHODS

A retrospective study was performed using the 2016-2019 National Inpatient Sample database. Adults who underwent suboccipital decompression for CM-I were identified using ICD-10-CM codes. Patients were stratified into two cohorts, those with AD and those without (No AD). Patient demographics, comorbidities, operative characteristics, perioperative adverse events (AEs), and healthcare resource utilization were assessed. Multivariate logistic regression analyses were used to identify independent predictors of prolonged length of stay (LOS), exorbitant admission costs, and non-routine discharge (NRD).

RESULTS

A total of 3985 patients were identified, of which 2780 (69.8%) were in the No AD cohort and 1205 (30.2%) were in the AD cohort. Patient demographics were similar, except for a greater proportion of Female patients than the No AD cohort (p = 0.004). Prevalence of some comorbidities varied between cohorts, including obesity (p = 0.030), ADHD (p < 0.001), GERD (p < 0.001), smoking (p < 0.001), and chronic pulmonary disease (p < 0.001). The AD cohort had a greater proportion of patients with 1-2 (p < 0.001) or ≥ 3 comorbidities (p < 0.001) compared to the No AD cohort. A greater proportion of patients in the AD cohort presented with headache compared to the No AD cohort (p = 0.003). Incidence of syringomyelia was greater in the No AD cohort (p = 0.002). A greater proportion of patients in the No AD cohort underwent duraplasty only (without cervical laminectomy) compared to the AD cohort (p = 0.021). Healthcare resource utilization was similar between cohorts, with no significant differences in mean LOS (No AD: 3.78 ± 3.51 days vs. 3.68 ± 2.71 days, p = 0.659), NRD (No AD: 3.8% vs. AD: 5.4%, p = 0.260), or mean admission costs (No AD: $20,254 ± 14,023 vs. AD: $29,897 ± 22,586, p = 0.284). On multivariate analysis, AD was not independently associated with extended LOS [OR (95%CI): 1.09 (0.72-1.65), p = 0.669], increased hospital costs [OR (95%CI): 0.98 (0.63-1.52), p = 0.930], or NRD [OR (95%CI): 1.39 (0.65-2.96), p = 0.302].

CONCLUSION

Our study suggests that the presence of an AD may not have as much of an impact on postoperative events and healthcare resource utilization in adult patients undergoing Chiari decompression. Additional studies may be warranted to identify other potential implications that AD may have in other aspects of healthcare in this patient population.

Three-Dimensional Volumetric Magnetic Resonance Imaging Analysis of Syringomyelia Evolution After Posterior Fossa Decompression for Chiari Malformation Type1

OBJECTIVE

This study aims to introduce a method of three-dimensional (3D) volume magnetic resonance imaging (MRI) measurements to evaluate the evolution of syringomyelia (SM) in adults with Chiari malformation type 1 (CM-1) after posterior fossa decompression (PFD), to provide reproducible and accurate measurements.

METHODS

Radiologic and clinical data were obtained for 28 patients. MRI 3D syrinx volumes were evaluated by 2 observers using Philips Healthcare Tumor Tracking tool.

RESULTS

The mean SM preoperative volume was 9.1 ± 15.3 cm3 versus 4.6 ± 8.7 cm3 postoperatively, corresponding to a volume variation reduced by -50% ± 33.4%. A total of 21 patients (75%) showed >25% reduction in SM volume postoperatively and 25 patients (89.2%) showed good to excellent postoperative clinical outcomes. Very high interobserver and intraobserver agreement was noted for 3D volumetric analysis with Cohen weighted κ coefficients (0.899-0.991). A negative correlation was found between the number of involved metameres and the postoperative SM volume reduction (Pearson correlation coefficient = 0.378; P = 0.047). Patients with better clinical outcomes had fewer syrinx septae (F = 8.830; P = 0.001). Similarly, better syrinx volume reduction was associated with fewer septae (F = 1.554; P = 0.233). A positive relationship was observed between clinical outcomes and postoperative syrinx volume reduction (F = 1.554; P= 0.233), with data similar to the reported literature.

CONCLUSIONS

This study shows that 3D volume measurement of the syrinx cavity on MRI is a reproducible and accurate method to assess the postoperative evolution of SM in CM-1 after PFD. Most patients (75%) showed a reduction of SM volume, with a mean volume decrease of 50%. The reliability is yet to be validated in further larger studies.

Foramen magnum decompression with cervical syringotomy for Chiari malformation type I with syringomyelia - A useful adjunct in selected cases

Background

Persistent or worsening syringomyelia after foramen magnum decompression (FMD) for Chiari I malformation (CIM) can be challenging to manage. We present a previously unpublished surgical technique of FMD with concomitant cervical syringotomy in selected patients.

Methods

A retrospective analysis of prospectively collected data was carried out. Patients who underwent FMD and expansion duraplasty (FMDD) with concomitant syringotomy were collected.

Results

Three patients with CIM with high cervical syringomyelia who underwent FMDD with concurrent syringotomy were identified. All cases had an idiopathic CIM. Improvement in clinical symptoms was noticed in all patients. Early postoperative imaging (within 6 weeks-4 months) showed syrinx transverse diameter reduction in the range of 85-100%. There were no postoperative complications.

Conclusion

FMDD with concurrent high cervical syringotomy through a standard approach in selected cases of CIM with high cervical syringes achieves clinical improvement without additional complications.

Suppression of TGFβR-Smad3 pathway alleviates the syrinx induced by syringomyelia

BACKGROUND

Syringomyelia is a cerebrospinal fluid (CSF) disorder resulted in separation of pain and temperature, dilation of central canal and formation of syrinx in central canal. It is unclear about mechanisms of the dilation and syrinx formation. We aimed to investigate roles of ependymal cells lining central canal on the dilation, trying to reduce syrinx formation in central canal.

METHODS

We employed 78 Sprague-Dawley (SD) rats totally with syringomyelia to detect the contribution of ependymal cells to the dilation of central canal. Immunofluorescence was used to examine the activation of ependymal cells in 54 syringomyelia rat models. BrdU was used to indicate the proliferation of ependymal cells through intraperitoneal administration in 6 syringomyelia rat models. 18 rats with syringomyelia were injected with SIS3, an inhibitor of TGFβR-Smad3, and rats injected with DMSO  were used as control. Among the 18 rats, 12 rats were used for observation of syrinx following SIS3 or DMSO administration by using magnetic resonance imaging (MRI) on day 14 and day 30 under syringomyelia without decompression. All the data were expressed as mean ± standard deviation (mean ± SD). Differences between groups were compared using the two-tailed Student's t-test or ANOVA. Differences were considered significant when *p < 0.05.

RESULTS

Our study showed the dilation and protrusions of central canal on day 5 and enlargement from day 14 after syringomyelia induction in rats with activation of ependymal cells lining central canal. Moreover, the ependymal cells contributed to protrusion formation possibly through migration along with central canal. Furthermore, suppression of TGFβR-Smad3 which was crucial for migration reversed the size of syrnix in central canal without treatment of decompression, suggesting TGFβR-Smad3 signal might be key for dilation of central canal and formation of syrinx.

CONCLUSIONS

The size of syrinx was decreased after SIS3 administration without decompression. Our study depicted the mechanisms of syrinx formation and suggested TGFβR-Smad3 signal might be key for dilation of central canal and formation of syrinx.

Reoperation in Chiari-1 Malformations

(1) Background: The issue of unsuccessful surgery for Chiari-1 malformation (CM-1), as well as its potential causes and possible solutions, remains poorly documented and studied. (2) Methods: From a retrospective review of a personal series of 98 patients undergoing treatment for CM-1 during the past 10 years, we created two study groups. Group 1: 8 patients (8.1%) requiring additional surgeries owing to postoperative complications (7 cerebrospinal fluid leakage, 1 extradural hematoma); 7 patients (7.1%) undergoing reoperations for failed decompression during the follow-up. Group 2: During the same period, we also managed 19 patients who had previously been operated on elsewhere: 8 patients who required adequate CM-1 treatment following extradural section of the filum terminale; 11 patients requiring reoperations for failed decompression. Failed decompression was managed by adequate osteodural decompression, which was associated with tonsillectomy (6 cases), subarachnoid exploration (8 cases), graft substitution (6 cases), and occipito-cervical fixation/revision (1 case). (3) Results: There was no mortality or surgical morbidity in Group 1. However, one patient's condition worsened due to untreatable syrinx. In Group 2, there were two cases of mortality, and surgical morbidity was represented by functional limitation and pain in the patient who needed revision of the occipitocervical fixation. Twenty patients improved (58.8%), 6 remained unchanged (32.3%), 1 worsened (2.9%) and 2 died (5.9%). (4) Conclusions: The rate of complications remains high in CM-1 treatment. Unfortunately, a certain rate of treatment failure is unavoidable, but it appears that a significant number of re-operations could have been avoided using proper indications and careful technique.

Knowledge mapping of syringomyelia from 2003 to 2022: A bibliometric analysis

BACKGROUND

Syringomyelia is a chronic, progressive disease of the spinal cord. Syringomyelia is an etiologically diverse affliction caused by disturbance of normal cerebrospinal fluid flow dynamics. Lesions are characterized by the formation of tubular cavities in the gray matter of the spinal cord and gliosis; however, the etiology is unknown and treatment methods differ. Many existing studies have focused on the relationship between other diseases and syringomyelia. There is a lack of comprehensive and objective reports on the research status of syringomyelia. Therefore, this study aimed to conduct a bibliometric analysis to quantify studies on Syringomyelia and trending issues in the last 20 years.

METHODS

Articles were acquired from the Web of Science Core Collection database. We used the Library Metrology online analysis platform, BICOMB, gCLUTO, CiteSpace bibliometrics tools for analysis, VOSviewer 1.6.16 (Nees Jan van Eck and Ludo Waltman, 2010), and Microsoft Excel 2019 to perform bibliometric analysis and visualization. Individual impact and collaborative information were quantified by analyzing annual publications, journals, co-cited journals, countries/regions, institutions, authors, and co-cited authors. We then identified the trending research areas of syringomyelia by analyzing the co-occurrence of keywords and co-cited references.

RESULTS

From January 2003 to August 2022, 9,556 authors from 66 countries published a total of 1,902 research articles on syringomyelia in 518 academic journals. Most publications come from the United States, China, the United Kingdom, and Japan, with the United States dominating. Nanjing University and the University of Washington are the most active institutions, Dr. Claire Rusbridge has published the most papers, and Miholat has the most co-citations. The Journal of Neurosurgery has the highest number of co-cited articles, which are mainly in the fields of neurology, surgery, and biology. High-frequency keywords included syringomyelia, Chiari-I malformation, children, surgical treatment, and spinal cord.

CONCLUSIONS

The number of articles on syringomyelia has increased steadily over the past two decades. At present, research on syringomyelia is mainly focused on the age of onset, potential therapeutic interventions, surgical treatment, avoidance of recurrence, and delay of pain. The use of surgical treatment of the disease and the mechanism of further treatment are the current hot research topics. The correlation between trauma and congenital factors, translational application, the effect of surgical treatment, postoperative recurrence, and complications are further hot research areas. These may provide ideas for further research into a radical cure for syringomyelia.

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.

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.

Surgical Management after Chiari Decompression Failure: Craniovertebral Junction Revision versus Shunting Strategies

Revision surgery after posterior fossa decompression for Chiari malformation is not uncommon and poses both strategic and technical challenges. We conducted a single-center retrospective cohort study including all adult patients who underwent revision surgery after posterior fossa decompression for Chiari type I malformation between 2010 and 2019. Among 311 consecutive patients operated on for Chiari malformation at our institution, 35 patients had a least one revision surgery with a mean follow-up of 70.2 months. Mean delay for revision was 28.8 months. First revision surgery was performed at the level of the foramen magnum in 25/35 cases and consisted in duraplasty revision in all cases, arachnolysis (51.4%), additional bone decompression (37.1%), tonsillar coagulation or resection (25.7%), 4th ventricle to cervical subarachnoid spaces shunt (5.7%). Most repeat revisions consisted in CSF diversion procedures, with either ventriculo-peritoneal or syringo-peritoneal shunts. Mean number of interventions per patient was 3.2, with 22.9% of patients undergoing 4 or more surgeries. Based on our experience, we propose that revision at the level of the foramen magnum should be considered as a first-line strategy for Chiari decompression failure. Shunting procedures can be performed in case of extensive arachnoiditis or repeated failures.

Treatment of syringomyelia using uncultured umbilical cord mesenchymal stem cells: A case report and review of literature

BACKGROUND

Syringomyelia is a disease caused by the formation of a cavity inside the spinal cord and is accompanied by such symptoms as pain, paresthesia, and urination and defecation disorders, and in severe cases causes various paralyses. Currently, there are only surgical methods for the treatment of syringomyelia, but these methods carry the possibility of failure, recurrence, and side effects.

CASE SUMMARY

The patient was a 59-year-old woman who suffered from pain due to syringomyelia. For treatment, the patient received transplant of uncultured umbilical cord-derived mesenchymal stem cells. As intended, the patient's pain was relieved after treatment. Interestingly, an additional benefit was found in that the size of the cavity also decreased. After 2 years from the last treatment, the patient's cavity had almost completely disappeared and her syringomyelia was deemed cured.

CONCLUSION

Using uncultured umbilical cord-derived mesenchymal stem cells may be a new treatment alternative for syringomyelia.

Diagnosis and treatment of Chiari malformation and syringomyelia in adults: international consensus document

BACKGROUND

Syringomyelia and Chiari malformation are classified as rare diseases on Orphanet, but international guidelines on diagnostic criteria and case definition are missing.

AIM OF THE STUDY

to reach a consensus among international experts on controversial issues in diagnosis and treatment of Chiari 1 malformation and syringomyelia in adults.

METHODS

A multidisciplinary panel of the Chiari and Syringomyelia Consortium (4 neurosurgeons, 2 neurologists, 1 neuroradiologist, 1 pediatric neurologist) appointed an international Jury of experts to elaborate a consensus document. After an evidence-based review and further discussions, 63 draft statements grouped in 4 domains (definition and classification/planning/surgery/isolated syringomyelia) were formulated. A Jury of 32 experts in the field of diagnosis and treatment of Chiari and syringomyelia and patient representatives were invited to take part in a three-round Delphi process. The Jury received a structured questionnaire containing the 63 statements, each to be voted on a 4-point Likert-type scale and commented. Statements with agreement <75% were revised and entered round 2. Round 3 was face-to-face, during the Chiari Consensus Conference (Milan, November 2019).

RESULTS

Thirty-one out of 32 Jury members (6 neurologists, 4 neuroradiologists, 19 neurosurgeons, and 2 patient association representatives) participated in the consensus. After round 2, a consensus was reached on 57/63 statements (90.5%). The six difficult statements were revised and voted in round 3, and the whole set of statements was further discussed and approved.

CONCLUSIONS

The consensus document consists of 63 statements which benefited from expert discussion and fine-tuning, serving clinicians and researchers following adults with Chiari and syringomyelia.

The Management of Idiopathic and Refractory Syringomyelia

Idiopathic syringomyelia (IS) and refractory syringomyelia (RS) are types of syringomyelia that often pose a management challenge and are associated with long-term clinical sequela. They are usually an epiphenomenon reflecting an underlying pathology where the treatment of the primary cause should be the aim for any surgical intervention. In the case of IS, the initial step is agreeing on the definition of the terms idiopathic and syringomyelia. After a rigorous exhaustive clinic-radiological workup, only IS patients with progressive neurology are treated, usually unblocking subarachnoid cerebrospinal fluid (CSF) pathway obstruction somewhere in the thoracic spinal canal and reserving shunting techniques to nonresponsive cases. Similar to IS, also RS is multifactorial, and its management varies based on the initial pathology, strongly supported by radiological and clinical features. We aim to address this topic focusing on the etiopathology, investigation paradigm, and surgical pathway, formulating algorithms of management with available evidence in literature. Surgical techniques are discussed in detail.

Comparison of Pericranial Autograft and AlloDerm for Duraplasty in Patients With Type I Chiari Malformation: Retrospective Cohort Analysis

BACKGROUND

Pericranial autograft is a popular option for duraplasty during Chiari decompression with several theoretical advantages, but comparisons to other materials have yielded mixed results.

OBJECTIVE

To compare outcomes between pericranial autograft and AlloDerm (BioHorizons).

METHODS

Consecutive suboccipital craniectomies for patients with type I Chiari malformation (CM-I) over an 8-yr period at a single institution were identified. Exclusion criteria included revision surgeries and suboccipital decompressions without duraplasty. Outcomes included incisional cerebrospinal fluid (CSF) leakage, length of stay (LOS), wound complication, aseptic meningitis, syrinx improvement, and symptomatic improvement.

RESULTS

A total of 101 patients (70 females and 31 males) with a median (interquartile range) age of 17 yr (11-32) met the inclusion criteria. There were 51 (50%) patients who underwent duraplasty with pericranial autograft, and the remainder underwent duraplasty with AlloDerm. There were 9 (9%) patients who experienced a postoperative CSF leak. After adjusting for confounding factors, obesity (odds ratio [OR]: 4.69, 95% CI: 1.03-25.6) and use of AlloDerm (OR: 10.54, 95% CI: 1.7-206.12) were associated with CSF leak. Wound complication occurred in 8 (8%) patients but was not associated with graft type (P = .8). Graft type was not associated with LOS, syrinx improvement, or symptom improvement. Reoperations occurred in 10 patients with 4 in the autograft group and 6 in the AlloDerm group (P = .71).

CONCLUSION

In patients with CM-I, expansile duraplasty with AlloDerm was associated with greater odds of CSF leakage than pericranial autograft. Obesity was also associated with increased odds of CSF leakage.

Management of Chiari type I malformation: a retrospective analysis of a series of 91 children treated surgically

INTRODUCTION

The diagnosis of Chiari I malformation, its symptomatology, and the results of its surgical management are still discussed. We report a pediatric series of CMI without associated skull base malformations or cerebellar growth anomalies operated between 2001 and 2018.

MATERIAL AND METHODS

Ninety-one children out of 146 surgically treated cases have been included in the study. Age at surgery ranged from 5 months to 17 years clinical data, and complementary examinations leading to the surgical indication have been analyzed together with the surgical outcomes. The average follow-up duration was of 4 years. The occipito-cervical decompression with duraplasty without opening the arachnoid was the procedure of election. Three quarters of patients presented with headaches, 12% with cerebellar syndrome, 13% with vertigo, 26% with nausea or vomiting, 24% with sensorimotor deficits, 11% with cranial nerve deficits, and 29% with other symptoms. Eighteen percent of patients suffered from scoliosis, 47% had an associated syrinx and 16% a ventricular dilation.

RESULTS

After the treatment, the clinical symptomatology improved in about three-quarters of the patients: headache (69.4%), nausea or vomiting (66.7%), sensorimotor deficits (55.6%), and other symptoms (78.3%). Syringomyelic cavities diminished partially in size or disappeared in 58.3% of patients, remained stable in 29.2%, and worsened in 12.5%. Only one-third of children with preoperative scoliosis benefited from the surgical treatment. No clinical signs or symptoms were found to be reliable predictors of surgical success, neither the extent of the cerebellar tonsil descent.

CONCLUSION

Occipito-cervical decompression allows to improve the clinical condition in the majority of children with symptomatic CMI in the absence of associated cervico-spinal junction alterations, craniosynostosis, or cerebellar growth anomalies. No clinical signs or symptoms neither radiological criterion appear to be a specific finding for the surgical indication.

Nonoperative management of enlarging syringomyelia in clinically stable patients after decompression of Chiari malformation type I

OBJECTIVE

The authors aimed to describe the natural history and optimal management of persistent syringomyelia after suboccipital craniectomy for Chiari malformation type I (CM-I).

METHODS

A cohort of all patients who presented to a tertiary pediatric hospital with newly diagnosed CM-I between 2009 and 2017 was identified. Patients with persistent or worsened syringomyelia were identified on the basis of a retrospective review of medical records and imaging studies. The management of these patients and their clinical courses were then described.

RESULTS

A total of 153 children with CM-I and syringomyelia were evaluated between 2009 and 2017. Of these, 115 (68.8%) patients underwent surgical intervention: 40 patients underwent posterior fossa decompression (PFD) alone, 43 underwent PFD with duraplasty, and 32 underwent PFD with duraplasty and fourth ventricle stent placement. Eleven (7.19%) patients had increased syringomyelia on subsequent postoperative imaging. Three of these patients underwent revision surgery because of worsening scoliosis or pain, 2 of whom were lost to follow-up, and 4 were managed nonoperatively with close surveillance and serial MRI evaluations. The syringes decreased in size in 3 patients and resolved completely in 1 patient.

CONCLUSIONS

Persistent or worsened syringomyelia after CM-I decompression is uncommon. In the absence of symptoms, nonoperative management with close observation is safe for patients with persistent syrinx.

Spontaneous resolution of a Chiari malformation with syringomyelia

The Chiari I malformation (CM-I) is characterised by overcrowding of the posterior fossa and descent of the cerebellar tonsils and is associated with syringomyelia. With the increasing availability of magnetic resonance imaging, CM-I is placing a growing burden on neurosurgical services. However, its natural history remains poorly understood, and the timing and nature of surgical intervention is controversial. We present a case of a significant, symptomatic CM-I with associated syrinx which underwent complete spontaneous resolution over a 4-year period. Spontaneous regression of Chiari malformation and syringomyelia is exceedingly rare; a literature review reveals 15 other cases and only one case which underwent complete resolution. The present case and literature review suggest a more benign natural history of CM-I and support a more conservative approach to its management. Further studies are required to determine whether any factors can predict resolution for certain patient cohorts.

Clinical Application of Diffusion Tensor Imaging in Chiari Malformation Type I- Advances and Perspectives. A Systematic Review

BACKGROUND

Diffusion tensor imaging (DTI) application in Chiari malformation type I (CMI) is still poorly defined. This study aimed to systematically review the literature and propose perspectives toward the clinical application of DTI in CMI.

METHODS

PubMed and Embase were searched for English-language articles published until October 20, 2020. Clinical studies and case series, evaluating fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), or radial diffusivity values in patients with CMI, were included.

RESULTS

Eight articles were included. Lower FA values were found at the syrinx level, which decreased with syrinx extent and intensity of symptoms, reflecting myelopathy severity. Decreased AD and MD in the middle cerebellar peduncles in symptomatic patients with CMI might explain the presence of cerebellar signs. Increased FA in various supratentorial structures positively correlated with pain severity. Worse performance in neuropsychological tests correlated with decreased FA, increased MD, and radial diffusivity, reflecting axonal degeneration. Postoperative FA decrease in the brainstem compression area reflects successful decompression. A positive correlation was found between the extent of tonsillar ectopia and increased FA, MD, and AD values, which could act as an early indicator of acute brainstem compression.

CONCLUSIONS

DTI might provide a valuable insight into the neurobiological foundation of symptomatic CMI presentation. The severity of white matter injury evident on DTI could serve as a reliable predictor of postoperative outcomes, therefore facilitating selection of appropriate surgical candidates. Postinterventional DTI reassessment might enable differentiation between unsuccessful surgical technique and irreversible myelopathy. The extent of tonsillar ectopia reflects the severity of microstructural brainstem injury.

Feasibility of occipital condyle screw placement in patients with Chiari malformation type I: a computed tomography-based morphometric study

BACKGROUND

The occipital condyle (OC) screw is an alternative technique for occipitocervical fixation that is especially suitable for revision surgery in patients with Chiari malformation type I (CMI). This study aimed to investigate the feasibility and safety of this technique in patients with CMI.

METHODS

The CT data of 73 CMI patients and 73 healthy controls were retrospectively analyzed. The dimensions of OCs, including length, width, height, sagittal angle, and screw length, were measured in the axial, sagittal, and coronal planes using CT images. The OC available height was measured in the reconstructed oblique parasagittal plane of the trajectory.

RESULTS

The mean length, width, and height of OCs in CMI patients were 17.79 ± 2.31 mm, 11.20 ± 1.28 mm, and 5.87 ± 1.29 mm, respectively. All OC dimensions were significantly smaller in CMI patients compared with healthy controls. The mean screw length and sagittal angle were 19.13 ± 1.97 mm and 33.94° ± 5.43°, respectively. The mean OC available height was 6.36 ± 1.59 mm. According to criteria based on OC available height and width, 52.1% (76/146) of OCs in CMI patients could safely accommodate a 3.5-mm-diameter screw.

CONCLUSIONS

The OC screw is feasible in approximately half of OCs in CMI patients. Careful morphometric analyses and personalized surgical plans are necessary for the success of this operation in CMI patients.

Natural History and Conservative Treatment Options in Chiari Malformation Type I in Adults: A Literature Update

Over the years, knowledge regarding the natural history of Chiari malformation type I (CM-I) has improved. However, there are still uncertainties in the literature regarding asymptomatic and oligosymptomatic patients with CM-I. We performed a literature review in order to determine the natural history of CM-I in symptomatic patients who were not operated and in asymptomatic adult patients. Among symptomatic patients, the most frequent symptom was headache (77%). Cough-related headache alone (34%), migraine-related headache alone (21.4%), and both cough- and migraine-related headaches (21.8%) were the most prevalent forms of headache. Some symptoms improved more effectively with surgical treatment options; cough-related headaches improved by 95% following surgery and by 40% following conservative treatment. Other headache types improved by 93% and 61.5% following conservative and surgical treatments, respectively. Patients diagnosed with asymptomatic or oligosymptomatic CM-I may improve over time or stabilize with conservative treatment. There is great heterogeneity in the literature regarding the diagnostic criteria for CM-I. Owing to the heterogeneity among the articles identified for this review, there is no consensus regarding the precise indications for surgery in asymptomatic patients. The natural CM-I history in asymptomatic patients reveals a favorable evolution.

Neurosarcoidosis in acute inpatient rehabilitation: a case study

INTRODUCTION

Sarcoidosis affects the nervous system in ~5-10% of cases. Common presentations for neurosarcoidosis can include facial nerve neuropathy, optic neuritis, meningitis, seizure muscle weakness, and paresthesia. Due to the complex treatment of neurosarcoidosis, few reports exist involving patients' recovery in an acute rehabilitation setting.

CASE PRESENTATION

We describe a case of neurosarcoidosis affecting the cervical and thoracic spinal cord in an individual with known Chiari I malformation and associated syrinx decompression.

DISCUSSION

We discuss the diagnosis and treatment of neurosarcoidosis and clinical implications of acute rehabilitation on functional recovery.

Minimally invasive foramen magnum durectomy and obexostomy for treatment of craniocervical junction-related syringomyelia in adults: case series and midterm follow-up

OBJECTIVE

Craniocervical junction-related syringomyelia (CCJS) is the most common form of syringomyelia. Approximately 30% of patients treated with foramen magnum decompression (FMD) will show persistence, recurrence, or progression of the syrinx. The authors present a pilot study with a new minimally invasive surgery technique targeting the pathophysiology of CCJS in adult patients.

METHODS

The authors retrospectively analyzed the clinical and radiological features of a consecutive series of patients treated for CCJS. An FMD and FM durectomy were performed through a 1.5- to 2-cm skin incision. Then arachnoid adhesions were cleared, creating a permanent communication from the fourth ventricle to the new paraspinal extradural cavity (obexostomy) and with the spinal subarachnoid space. The hypothesis was that the new CSF pouch acts like a pressure leak, interrupting the CCJS pathogenesis.

RESULTS

Twenty-four patients (13 female, 21-61 years old) were treated between 2014 and 2018. The etiology of CCJS was Chiari malformation type I (CM-I) in 20 patients (83.3%), Chiari malformation type 0 (CM-0) in 2 patients (8.3%), and CCJ arachnoiditis in 2 patients (8.3%). Two patients underwent reoperations after failed FMD for CM-I at other institutions. No major surgical complication occurred. One patient had postoperative meningitis with no CSF fistula. On postoperative MRI, shrinkage of the syrinx was seen in all patients. No patients experienced recurrence of the CCJS. No patient required a subsequent operation. The mean duration of surgery was 72 ± 11 minutes (mean ± SD), and blood loss was 35-80 ml (mean 51 ml). Follow-up ranged from 12 to 58 months. The average overall improvement in modified Japanese Orthopaedic Association scores was 10% (p < 0.001). The Odom scale showed that 19 patients (79.1%) were satisfied, 4 (16.7%) remained the same, and 1 (4.2%) reported a poor outcome. All patients experienced postoperative improvement in perception of quality of life (p < 0.001).

CONCLUSIONS

Minimally invasive FM durectomy and obexostomy is a safe and effective treatment for CCJS and for patients who have not responded to other treatment.

Syringomyelia as a delayed complication of lumbar-sacral adhesive arachnoiditis in Pott's disease

Syringomyelia is the development of a fluid-filled cyst (syrinx) within the spinal cord and is an extremely rare chronic manifestation of tuberculosis. The syrinx so formed may expand over time, causing compression or destruction of spinal tracts and surrounding nerve roots. Development of syringomyelia in a patient of Pott's disease is particularly infrequent. We report this rare case of a 31-year-old man with syringomyelia as a prolonged complication of Pott's disease.

Direct syrinx drainage in patients with Chiari I malformation

While FMD is, to date, the primary treatment of symptomatic CM I, the treatment of Chiari malformation type I (CM I) associated syrinx remains controversial. In cases of persistent, progressive, or recurrent syrinx following FMD, direct syrinx drainage (DSD) is described as a safe and efficient option, leading to a good clinical and radiological outcome. However, studies at hand mostly include very heterogeneous patient populations, small cohorts, and are of retrospective nature. We provide an overview of the possible indications and outcome for DSD in CM I-associated syrinx. We discuss the different surgical techniques of DSD and review the available literature comparing different DSD techniques. Finally, we discuss the possible complications that might occur after DSD and how they can be prevented.

International survey on the management of Chiari 1 malformation and syringomyelia: evolving worldwide opinions

INTRODUCTION

In 2003, pediatric neurosurgeons were surveyed under the auspices of the education committee of the International Society for Pediatric Neurosurgery (ISPN) to determine prevailing opinions regarding the management of Chiari I malformation (C1M) with and without associated syringomyelia. In the ensuing years, there has been further information from multiple C1M studies, with regards to indications, success rates of different surgical interventions, and complications. The purpose of this study was to re-evaluate current opinions and practices in pediatric C1M.

MATERIALS AND METHODS

Pediatric neurosurgeons worldwide were surveyed, using an e-mail list provided by the ISPN communication committee chairperson. Respondents were given scenarios similar to the 2003 C1M survey in order to determine opinions regarding whether to surgically intervene, and if so, with which operations.

RESULTS

Of 300 surveys electronically distributed, 122 responses were received (40.6% response rate)-an improvement over the 30.8% response rate in 2003. Pediatric neurosurgeons from 34 different countries responded. There was broad consensus that non-operative management is appropriate in asymptomatic C1M (> 90%) as well as asymptomatic C1M with a small syrinx (> 65%). With a large syrinx, a majority (almost 80%) recommended surgical intervention. Scoliotic patients with CIM were generally offered surgery only when there was a large syrinx. There has been a shift in the surgical management over the past decade, with a bone-only decompression now being offered more commonly. There remains, however, great variability in the operation offered.

CONCLUSION

This survey, with a relatively strong response rate, and with broad geographic representation, summarizes current worldwide expert opinion regarding management of pediatric C1M. Asymptomatic C1M and C1M with a small syrinx are generally managed non-operatively. When an operation is indicated, there has been a shift towards less invasive surgical approaches.

Treatment of Syringomyelia in Patients with Arachnoiditis at the Craniocervical Junction

OBJECTIVE

Craniocervical junction arachnoiditis (CCJA) is an uncommon cause of syringomyelia. The pathophysiology of syrinx formation is uncertain, and the appropriate management unclear. A series of cases is reported to demonstrate variations in etiology, uniformity of functional cerebrospinal fluid obstruction at the foramen magnum, and results of surgical intervention.

METHODS

We retrospectively analyzed the clinical and radiologic features of a consecutive series of patients treated for syringomyelia related to CCJA.

RESULTS

Eight patients (5 male, 28-66 years old) were treated from 2000 to 2016. Magnetic resonance imaging demonstrated cervicothoracic syringomyelia in all cases, with the rostral extension of the syrinx suggesting communication with the fourth ventricle in all but one case. There was reduction of foramen magnum cerebrospinal fluid space in all cases, cerebellar ectopia in 5 cases, and fourth ventricular entrapment in 3 cases. Treatment consisted of posterior fossa decompression with either a GoreTex or pericranial patch graft. Six patients had a fourth-ventricle spinal subarachnoid shunt. Two patients had titanium mesh cranioplasty. The immediate postoperative period was associated with reduction in syrinx cavity size and improvement in neurologic symptoms in all cases. At follow-up 10-60 months postoperatively, 3 patients exhibited recurrence of the syrinx and underwent successful reoperation at the craniocervical junction. One patient with persistence of the inferior component of the syrinx was treated with a syrinx-spinal subarachnoid shunt.

CONCLUSIONS

Most syrinx cavities associated with CCJA communicate with the fourth ventricle. Posterior fossa decompression and fourth ventricle to spinal subarachnoid space shunting appears a reasonable treatment for this form of syringomyelia.

Syringohydromyelia in Patients with Chiari I Malformation: A Retrospective Analysis

BACKGROUND AND PURPOSE

The association of syringohydromyelia with Chiari I malformation has a wide range, between 23% and 80% of cases in the current literature. In our experience, this range might be overestimated compared with our observations in clinical practice. Because there is an impact of Chiari I malformation-associated syringohydromyelia on morbidity and surgical intervention, its diagnosis is critical in this patient population. Identifying related variables on the basis of imaging would also help identify those patients at risk of syrinx formation during their course of disease.

MATERIALS AND METHODS

We performed a retrospective analysis of the MR imaging studies of 108 consecutive cases of Chiari I malformation. A multitude of factors associated with syrinx formation were investigated, including demographic, morphometric, osseous, and dynamic CSF flow evaluation.

RESULTS

Thirty-nine of 108 (36.1%) patients with Chiari I malformation had syringohydromyelia. On the basis of receiver operating characteristic curve analysis, a skull base angle (nasion-sella-basion) of 135° was found to be a statistically significant classifier of patients with Chiari I malformation with or without syringohydromyelia. Craniocervical junction osseous anomalies (OR = 4.3, P = .001) and a skull base angle of >135° (OR = 4.8, P = .0006) were most predictive of syrinx formation. Pediatric patients (younger than 18 years of age) who developed syringohydromyelia were more likely to have associated skull base osseous anomalies than older individuals (P = .01).

CONCLUSIONS

Our findings support evidence of the role of foramen magnum blockage from osseous factors in the development of syringohydromyelia in patients with Chiari I malformation.

Chiari Malformation Type 1: A Systematic Review of Natural History and Conservative Management

BACKGROUND

Chiari malformation type 1 (CM-1) is a variation of hindbrain development that can sometimes occur in asymptomatic individuals. Conventional treatment is surgical decompression, but little is known about the natural history of patients who do not undergo surgical management. This information is critical to determine how these patients should be managed. We conducted a systematic literature review to determine the natural history of CM-1, particularly in patients who did not undergo surgery and in asymptomatic individuals, to help patients and physicians determine when surgery is likely to be beneficial.

METHODS

The literature search was performed following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines using the electronic databases PubMed, Scopus, Cochrane Library, and Web of Science. Inclusion and exclusion criteria were predefined.

RESULTS

In symptomatic patients who did not undergo surgery, headaches and nausea often improved, whereas ataxia and sensory disturbance tended not to improve spontaneously. Of patients, 27%-47% had an improvement in symptoms after 15 months, and 37%-40% with cough headache and 89% with nausea who were managed nonoperatively improved at follow-up. Most asymptomatic individuals with CM-1 remained asymptomatic (93.3%) even in the presence of syringomyelia.

CONCLUSIONS

The natural history of mild symptomatic and asymptomatic CM-1 in adults is relatively benign and nonprogressive; the decision to perform surgical decompression should be based on severity and duration of a patient's symptoms at presentation. It is reasonable to observe a patient with mild or asymptomatic symptoms even in the presence of significant tonsillar descent or syringomyelia.

Chiari malformation type I with cervicothoracic syringomyelia masquerading as bibrachial amyotrophy: a case report

INTRODUCTION

Clinical presentation of syringomyelia can mimic a variety of neuromuscular disorders. A misdiagnosis can result in progressive pressure on the spinal cord, causing the development of severe irreversible neurologic deficits.

CASE PRESENTATION

We report the very unusual case of a 50-year-old Latino man who developed severe distal muscle atrophy and bulbar dysfunction as a result of Chiari malformation type I with chronic cervicothoracic syringomyelia.

CONCLUSION

Syringomyelia is a potentially serious neurologic condition with symptoms that can mimic other neuromuscular disorders. Severe untreated cases can result in irreversible spinal cord injury. Prompt diagnosis with magnetic resonance imaging is important in both establishing diagnosis and directing further surgical management.

Syrinx resolution is correlated with the upward shifting of cerebellar tonsil following posterior fossa decompression in pediatric patients with Chiari malformation type I

PURPOSE

Chiari malformation type I (CMI) is characterized by deformed hindbrain. This study aimed to quantitatively evaluate the alterations in position of hindbrain after Posterior fossa decompression (PFD), and to identify the factors associated with syrinx resolution in pediatric patients with CMI.

METHODS

Eighty-seven patients, aged from 5 to 18 years, who underwent PFD for CMI between September 2006 and September 2012 were retrospectively reviewed. On mid-sagittal MR images, the position of medulla oblongata and cerebellum was quantitatively evaluated preoperatively and at follow-up. The maximal syrinx/cord (S/C) ratio and syrinx length were also measured. Significant improvement of syrinx was defined as a more than 20 % decrease in maximal S/C ratio or length on follow-up MRI.

RESULTS

Neurological deficits were found in 51 of the 87 patients preoperatively and 37 (72.4 %) of them obtained improvement of their symptoms at the last visit. Overall, upward shifting of the tip of cerebellar tonsil was observed in 66 (75.9 %) patients at the last follow-up. Moreover, the mean longitudinal distance of the tip of cerebella tonsil changed from 16.47 ± 5.00 to 13.89 ± 4.38 mm (P < 0.001) at final follow-up. Significant syrinx resolution was noticed in 79 (90.8 %) cases. Pointed cerebellar tonsils were found in 85 (97.7 %) of our patients preoperatively and 78 (91.8 %) of them acquired round cerebellar tonsils after PFD. The improvement of maximal S/C ratio was significantly correlated with upward shifting of the tip of cerebellar tonsil (P = 0.023).

CONCLUSIONS

Following PFD for CMI, position and morphology of the cerebellar tonsil could revert to normal in most of the pediatric patients, and the upward shifting of the tip of cerebellar tonsil is significantly correlated with syrinx improvement. From this study, PFD without shunting may be effective for syrinx secondary to CMI in pediatric population.