The management of Chiari malformation type 1 and syringomyelia in children: a review of the literature.

In anticipation of the "Chiari and Syringomyelia Consensus Conference" held in Milan in 2019, we performed a systematic literature review on the management of Chiari malformation type 1 (CM1) and syringomyelia (Syr) in children.We aimed to summarize the available evidence and identify areas where consensus has not been reached and further research is needed.In accordance with PRISMA guidelines, we formulated seven questions in Patients-Interventions-Comparators-Outcomes (PICO) format. Six PICOs concerned CM1 children with/without additional structural anomalies (Syr, craniosynostosis, hydrocephalus, tethered cord, and cranio-vertebral junction anomalies), and one PICO Syr without CM1. We searched Medline, Embase, Cochrane, and NICE databases from January 1, 1999, to May 29, 2019. Cohort studies, controlled and randomized clinical trials (CCTs, RCTs), and systematic reviews were included, all pertinent only to patients ≤ 18 years of age.For CM1, 3787 records were found, 460 full texts were assessed and 49 studies (46 cohort studies, one RCT, and two systematic reviews) were finally included. For Syr, 376 records were found, 59 full texts were assessed, and five studies (one RCT and four cohort studies) were included. Data on each PICO were synthetized narratively due to heterogeneity in the inclusion criteria, outcome measures, and length of follow-up of the included studies.Despite decades of experience on CM1 and Syr management in children, the available evidence remains limited. Specifically, there is an urgent need for collaborative initiatives focusing on the adoption of shared inclusion criteria and outcome measures, as well as rigorous prospective designs, particularly RCTs.

Syringomyelia: diagnosis and management.

In the pre-MR era syringomyelia often presented late, as a crippling neurological disorder. Today, most cases are diagnosed earlier, with less pronounced deficits. We are therefore presented with new challenges, including understanding the significance of various presenting symptoms, knowing when surgery might help and being aware of other treatments that could benefit someone living with the effects of syringomyelia, or its underlying cause.

Scoliosis in patients with Chiari malformation type I.

The literature about the association between Chiari malformations (CMs) and scoliosis has been growing over the last three decades; yet, no consensus on the optimal management approach in this patient population has been reached. Spinal anomalies such as isolated syrinxes, isolated CM, and CM with a syrinx are relatively common among patients with presumed idiopathic scoliosis (IS), a rule that also applies to scoliosis among CM patients as well. In CM patients, scoliosis presents with atypical features such as early onset, left apical or kyphotic curvature, and neurological deficits. While spinal X-rays are essential to confirm the diagnosis of scoliosis among CM patients, a magnetic resonance imaging (MRI) is also recommended in IS patients with atypical presentations. Hypotheses attempting to explain the occurrence of scoliosis in CM patients include cerebellar tonsillar compression of the cervicomedullary junction and uneven expansion of a syrinx in the horizontal plane of the spinal cord. Early detection of scoliosis on routine spinal examination and close follow-up on curve stability and progression are essential initial steps in the management of scoliosis, especially in patients with CM, who may require full spine MRI to screen for associated neuro-axial anomalies; bracing and spinal fusion may be subsequently pursued in high-risk patients.

Cell therapy with autologous mesenchymal stromal cells in post-traumatic syringomyelia.

BACKGROUND AIMS: Recently, clinical studies show that cell therapy with mesenchymal stromal cells (MSCs) improves the sequelae chronically established in paraplegic patients, being necessary to know which of them can obtain better benefit. METHODS: We present here a phase 2 clinical trial that includes six paraplegic patients with post-traumatic syringomyelia who received 300 million MSCs inside the syrinx and who were followed up for 6 months. Clinical scales, urodynamic, neurophysiological, magnetic resonance (MR) and studies of ano-rectal manometry were performed to assess possible improvements. RESULTS: In all the cases, MR at the end of the study showed a clear reduction of the syrinx, and, at this time, signs of improvement in the urodynamic studies were found. Moreover, four patients improved in ano-rectal manometry. Four patients improved in neurophysiological studies, with signs of improvement in evoked potentials in three patients. In the American Spinal Injury Association (ASIA) assessment, only two patients improved in sensitivity, but clinical improvement in neurogenic bowel dysfunction was observed in four patients and three patients described improvement in bladder dysfunction. Spasms reduced in two of the five patients who had them previous to cell therapy, and spasticity was improved in the other two patients. Three patients had neuropathic pain before treatment, and it was reduced or disappeared completely during the study. Only two adverse events ocurred, without relation to the cell therapy. CONCLUSIONS: Cell therapy can be considered as a new alternative to the treatment of post-traumatic syringomyelia, achieving reduction of syrinx and clinical improvements in individual patients.

Anesthetic and Obstetric Management of Syringomyelia During Labor and Delivery: A Case Series and Systematic Review.

BACKGROUND: Syringomyelia is a rare, slowly progressive neurological condition characterized by the presence of a syrinx within the spinal cord. Consensus regarding the safest mode of delivery and anesthetic management in patients with syringomyelia remains controversial and presents management dilemmas. This study reviews the cases of syringomyelia at our institution and provides a systematic review of the literature to guide decisions regarding labor and delivery management. METHODS: A retrospective review of cases at our hospital from 2002 to 2014 and a systematic review of the literature from 1946 to 2014 were undertaken. Hospital records and electronic databases were interrogated using International Classification of Diseases, 10th Revision codes and the keywords "syringomyelia," "syringobulbia," and "pregnancy." Data regarding demographics, diagnosis, radiology reports, neurological symptoms, mode of delivery, anesthetic management, and maternal-fetal outcomes were collected. RESULTS: We collected and analyzed data on a total of 43 pregnancies in 39 patients. The most common location for syrinx was in the cervicothoracic region (41.9%). The large majority of patients (n = 34; 87%) demonstrated signs and symptoms associated with syringomyelia before delivery. Syringomyelia associated with Arnold Chiari malformation was documented in 49% (n = 21) cases. General anesthesia was the most commonly used (n = 21/30, 70%) anesthetic technique for cesarean delivery. The majority (n = 9/13, 69%) of patients had an epidural sited for labor analgesia. There were no maternal or neonatal complications associated with neuraxial anesthesia; however, 3 cases (14%) raised concerns regarding general anesthesia including difficult intubation, transient worsening of neurological symptoms postpartum, and prolonged muscle paralysis after atracurium. CONCLUSIONS: Despite concerns regarding aggravation of the syrinx with vaginal delivery, this mode of delivery has never caused any documented long-term worsening of neurological condition. All techniques of anesthesia have been performed successfully without major lasting complications. All cases necessitate patient counseling and individualized multidisciplinary involvement to ensure maternal safety.

Chiari Type 1 Deformity in Children: Pathogenetic, Clinical, Neuroimaging, and Management Aspects.

Our understanding of cerebellar tonsillar herniation evolved over time and nowadays various pathomechanisms have been proposed. Causes of tonsillar herniation share a discrepancy between content (fore- and hindbrain) and container (supratentorial cranial vault, posterior fossa), may be associated with abnormalities of the craniocervical junction, and may have a developmental or acquired nature. In tonsillar herniation, the hindbrain is not malformed but deformed. Accordingly, "Chiari type 1 deformity," not "Chiari type 1 malformation" is the correct term to characterize primary tonsillar herniation. Chiari type 1 deformity is commonly seen in pediatric neurology, neuroradiology, and neurosurgery and may have various clinical presentations depending on patient age. In addition, Chiari type 1 deformity is increasingly found by neuroimaging studies as an incidental finding in asymptomatic children. An accurate and reliable selection of patients based on clinical and neuroimaging findings is paramount for the success of neurosurgical treatment. Future studies are needed to provide selection criteria with a higher sensitivity and specificity.

Spinal cord stimulation combined with microsurgical DREZotomy for pain due to syringomyelia.

A 49-year-old man with lower extremity neuropathic pain thought to be caused by spinal cord syringomyelia was treated with a combination of using spinal cord stimulation, decompression of the syrinx, relief of arachnoid adhesions and microsurgical DREZotomy. The patient had significant pain relief and has stable neurological status at follow-up.

Syringomyelia in an older patient.

We describe the case of an 80-year-old man who presented with lower limb upper motor neurone weakness and spinothalamic tract sensory deficit secondary to previously undiagnosed syringomyelia. The case highlights the need for methodical history, examination and investigation in elderly patients to achieve diagnostic accuracy.

Currarino syndrome: report of five consecutive patients.

INTRODUCTION: The Currarino syndrome is regarded as a developmental disorder based on its recognized etiological heterogeneity. This syndrome is thought to result from abnormal separation of the neuroectoderm from the endoderm. Our aim was to report the neurosurgical management of Currarino syndrome in children and adults and to describe what clinician could do if the Currarino triad was suspected. CASE REPORTS: We present five cases of Currarino triad who underwent surgical intervention. All patients had sacral bony deformity, anorectal malformations, and anterior sacral meningocele. A 40-year-old-male had chronic constipation. He was incidentally diagnosed with Currarino syndrome. A 19-year-old-female suffered from a slight weakness in lower extremities and urinary incontinence. Her past medical history was remarkable for anal atresia. The other three cases were children. CONCLUSION: When an anterior sacral meningocele is encountered, Currarino syndrome should be taken into consideration. Although it is rarity, the Currarino syndrome might be one of the causes of chronic constipation. Endoscopic or endoscope-assisted surgery via a posterior sacral route can be feasible for treatment of some of the patients with anterior sacral meningocele. Anterior meningocele pouch associated with Currarino syndrome will regresses over time following transdural ligation of its neck.

Treatment of Syringomyelia Characterized by Focal Dilatation of the Central Canal Using Mesenchymal Stem Cells and Neural Stem Cells.

BACKGROUND: Syringomyelia is a progressive chronic disease that leads to nerve pain, sensory dissociation, and dyskinesia. Symptoms often do not improve after surgery. Stem cells have been widely explored for the treatment of nervous system diseases due to their immunoregulatory and neural replacement abilities. METHODS: In this study, we used a rat model of syringomyelia characterized by focal dilatation of the central canal to explore an effective transplantation scheme and evaluate the effect of mesenchymal stem cells and induced neural stem cells for the treatment of syringomyelia. RESULTS: The results showed that cell transplantation could not only promote syrinx shrinkage but also stimulate the proliferation of ependymal cells, and the effect of this result was related to the transplantation location. These reactions appeared only when the cells were transplanted into the cavity. Additionally, we discovered that cell transplantation transformed activated microglia into the M2 phenotype. IGF1-expressing M2 microglia may play a significant role in the repair of nerve pain. CONCLUSION: Cell transplantation can promote cavity shrinkage and regulate the local inflammatory environment. Moreover, the proliferation of ependymal cells may indicate the activation of endogenous stem cells, which is important for the regeneration and repair of spinal cord injury.

Morvan syndrome: clinical and serological observations in 29 cases.

OBJECTIVE: A study was undertaken to describe the clinical spectrum, voltage-gated potassium channel (VGKC) complex antibody specificities, and central nervous system localization of antibody binding in 29 patients diagnosed with Morvan syndrome (MoS). METHODS: Clinical data were collected using questionnaires. Radioimmunoassay, cell-based assays, and mouse brain immunohistochemistry were used to characterize the serum antibodies. RESULTS: Neuromyotonia (100%), neuropsychiatric features (insomnia 89.7%, confusion 65.5%, amnesia 55.6%, hallucinations 51.9%), dysautonomia (hyperhidrosis 86.2%, cardiovascular 48.3%), and neuropathic pain (62.1%) were the most common manifestations. A total of 93.1% of MoS patients were male. VGKC-complex antibodies were present in 23 of 29 (79%) MoS patients at referral; 24 of 27 available sera had CASPR2, LGI1, or both CASPR2 and LGI1 antibodies (3 also with contactin-2 antibodies). CASPR2 antibodies were generally higher titer than LGI1 antibodies. Tumors (41.4%), mainly thymomas, were associated with CASPR2 antibodies and a poor prognosis, whereas LGI1 antibodies were associated with serum hyponatremia. In brain tissue regions including the hypothalamus, raphe, and locus coeruleus, commercial antibodies to LGI1 bound to neuronal cell bodies including the antidiuretic hormone-secreting and orexin-secreting hypothalamic neurons, whereas CASPR2 commercial antibodies bound more often to the neuropil. MoS antibodies bound similarly, but there was evidence of additional antibodies in some sera that were not adsorbed by LGI1- or CASPR2-expressing cells and bound to mouse Caspr2(-/-) tissue. INTERPRETATION: MoS is clinically distinct from other VGKC-complex antibody-associated conditions, and usually is associated with high-titer CASPR2 antibodies, often accompanied by lower-titer LGI1 antibodies. CASPR2 and LGI1 antibodies bind to multiple brain regions, which helps to explain the multifocal clinical features of this disease, but other antibodies are likely to play a role in some patients and need to be characterized in future studies.

Management of isolated syringomyelia in the paediatric population--a review of imaging and follow-up in a single centre.

OBJECTIVE: To assess the natural history of isolated syringomyelia in children. METHODS: MRI reports from February 2007 to August 2011 mentioning syrinx were identified on Sheffield Children's PACS database. Scans with syringes having an AP diameter of > 1 mm and extending over at least two vertebral bodies were reviewed. Patients with an identifiable cause such as a Chiari malformation were then excluded. RESULTS: Thirty-nine patients were included with a mean age at diagnosis of 10.6 years. The average syrinx AP diameter was 3.30 mm. The rostrocaudal length of the syringes varied between 2 and 19 vertebral bodies. Twenty-seven out of 39 syringes were thoracic in origin. There were 3 and 6 syringes involving the cervicothoracic and thoracolumbar regions, respectively, with 3 involving the cervical area only. Eleven out of 39 (Group I) patients were found "incidentally" during work-up for adolescent idiopathic scoliosis and these were considered as a separate group. These patients did not have any significant symptoms and were discharged following their scoliosis correction surgery. Syrinx was incidental in 14 further patients (Group II). Of the 14 patients, 11 remained asymptomatic with no change in syrinx morphology throughout follow up. Of the 14 patients, 3 were lost to follow-up. Of the 39 patients, 14 (Group III) presented with progressive back pain without any obvious clinical cause. Of the 14, 10 either improved or remained the same. Of the 14 patients, 3 underwent lumbar puncture, 1/14 having myelography. All 4/14 patients reported significant pain reduction on follow up following intervention. CONCLUSION: Idiopathic syrinx is a benign pathology, which can be managed expectantly. Most cases remain stable or improve over time. In a small minority who have progressive back pain, we have found that lumbar puncture may be helpful in reducing symptoms.

Refractory Morvan syndrome responsive to rituximab: a case report and review of the literature.

Morvan Syndrome (MoS) is an autoimmune disorder characterized by peripheral nerve hyperexcitability, autonomic dysfunction, and encephalopathy. We describe the case of a man with a history of thymoma diagnosed with a paraneoplastic MoS with a severe painful neuropathy refractory to immunoglobulins and steroids who had a dramatic and lasting response following treatment with rituximab. We also reviewed the clinical features, comorbidities, laboratory findings, treatment responses, relapses, and long-term outcomes of all published cases of MoS treated with rituximab. This drug appears promising for the treatment of patients with MoS who failed first line therapy with immunoglobulins and steroids.

Active Conservative Management of Primary Spinal Syringomyelia: A Scoping Review and Perspectives for an Activity-based Clinical Approach.

OBJECTIVE: This scoping review aimed to identify and synthesize existing research on active conservative management of primary spinal syringomyelia and associated symptoms and to discuss perspectives for clinical application using an activity-based approach. METHODS: PubMed, Embase, Scopus, and Web of Science were systematically searched for empirical studies of conservative management or therapies of adults with primary spinal syringomyelia from inception to April 2021. In addition, abstracts from relevant conferences were searched. Study characteristics and key findings were extracted, and findings descriptively synthesized. RESULTS: Of 1,186 studies screened, 7 studies met the eligibility criteria (4 single case studies and 3 cohort studies, a total of 90 individuals). The interventions were primarily physiotherapeutic, mostly by posture correction and exercises, and effects were alleviation of pain, improved physical function, improved activities of daily living and quality of life. Analysis of factors triggering symptoms and rationale for choice of intervention based upon these was limited. CONCLUSION: Evidence of active conservative management of primary spinal syringomyelia and associated symptoms is limited. Many variations and limitations in the existing research limit the conclusions. High-quality research is needed to enable healthcare professionals to apply evidencebased active conservative interventions.

Effect of mesenchymal stem cells therapy in experimental kaolin induced syringomyelia model.

BACKGROUND: Syringomyelia is a pathological cavitation of the spinal cord. In this study, we examined whether a syrinx cavity would limit itself with axonal regeneration and stem cell activity in the cavity, and we evaluated subjects on a functional basis. METHODS: Groups were designated as kaolin, trauma, kaolin-trauma, and saline groups. Also divided out of the syringomyelia treated groups were those given human mesenchymal stem cells (hMSCs). All groups were evaluated with immunohistochemistry, electron microscopy, confocal microscopy and functionally. RESULTS: The kaolin-trauma group had a significant correction of BBB score with hMSCs therapy. The syrinx cavity measurements showed significant improvement in groups treated with hMSCs. The tissue surrounding the syrinx cavity, however, appeared to be better organized in groups treated with hMSCs. The process of repair and regeneration of damaged axons in the lesion were more improved in groups treated with hMSCs. Using confocal microscopy, fluorescence of hMSCs was observed in the central canal, in the ependymal tissue, and around the lesion. CONCLUSIONS: It was concluded that axonal repair accelerated in groups receiving stem cells, and thus, stem cells may be effective in recovery of neural tissue and myelin damage in syringomyelia.

Multiple therapeutic effects of human neural stem cells derived from induced pluripotent stem cells in a rat model of post-traumatic syringomyelia.

BACKGROUND: Post-traumatic syringomyelia (PTS) affects patients with chronic spinal cord injury (SCI) and is characterized by progressive deterioration of neurological symptoms. To improve surgical treatment, we studied the therapeutic effects of neuroepithelial-like stem cells (NESCs) derived from induced pluripotent stem cells (iPSCs) in a rat model of PTS. To facilitate clinical translation, we studied NESCs derived from Good Manufacturing Practice (GMP)-compliant iPSCs. METHODS: Human GMP-compliant iPSCs were used to derive NESCs. Cryo-preserved NESCs were used off-the-shelf for intraspinal implantation to PTS rats 1 or 10 weeks post-injury, and rats were sacrificed 10 weeks later. In vivo cyst volumes were measured with micro-MRI. Phenotypes of differentiated NESCs and host responses were analyzed by immunohistochemistry. FINDINGS: Off-the-shelf NESCs transplanted to PTS rats 10 weeks post-injury reduced cyst volume. The grafted NESCs differentiated mainly into glial cells. Importantly, NESCs also stimulated tissue repair. They reduced the density of glial scars and neurite-inhibiting chondroitin sulfate proteoglycan 4 (CSPG4), stimulated host oligodendrocyte precursor cells to migrate and proliferate, reduced active microglia/macrophages, and promoted axonal regrowth after subacute as well as chronic transplantation. INTERPRETATION: Significant neural repair promoted by NESCs demonstrated that human NESCs could be used as a complement to standard surgery in PTS. We envisage that future PTS patients transplanted with NESCs will benefit both from eliminating the symptoms of PTS, as well as a long-term improvement of the neurological symptoms of SCI. FUNDING: This work was supported by Vinnova (2016-04134), Karolinska Institutet StratRegen, and the Chinese Scholarship Council.

Neck pain and Headache Complicated by Persistent Syringomyelia After Foramen Magnum Decompression for Chiari I Malformation: Improvement with Multimodal Chiropractic Therapies.

BACKGROUND Patients with Arnold-Chiari Malformation I (CM-I) treated with foramen magnum decompression (FMD) can have ongoing neck pain, headaches, and other symptoms complicated by persistent syringomyelia, yet there is little research regarding treatment of these symptoms. CASE REPORT A 62-year-old woman with a history of residual syringomyelia following FMD and ventriculoperitoneal shunt for CM-I presented to a chiropractor with progressively worsening neck pain, occipital headache, upper extremity numbness and weakness, and gait abnormality, with a World Health Organization Quality of Life score (WHO-QOL) of 52%. Symptoms were improved by FMD 16 years prior, then progressively worsened, and had resisted other forms of treatment, including exercises, acupuncture, and medications. Examination by the chiropractor revealed upper extremity neurologic deficits, including grip strength. The chiropractor ordered whole spine magnetic resonance imaging, which demonstrated a persistent cervico-thoracic syrinx and findings of cervical spondylosis, and treated the patient using a multimodal approach, with gentle cervical spine mobilization, soft tissue manipulation, and core and finger muscle rehabilitative exercises. The patient responded positively, and at the 6-month follow-up her WHO-QOL score was 80%, her grip strength and forward head position had improved, and she was now able to eat using chopsticks. CONCLUSIONS This case highlights a patient with neck pain, headaches, and persistent syringomyelia after FMD for CM-I who improved following multimodal chiropractic and rehabilitative therapies. Given the limited, low-level evidence for these interventions in patients with persistent symptoms and syringomyelia after FMD, these therapies cannot be broadly recommended, yet could be considered on a case-by-case basis.

Chiari and Syringomyelia Consortium: a model of multidisciplinary and sharing path for rare diseases.

Piemonte and Valle d'Aosta Interregional Network for Rare Diseases (RD) is a model of "diffuse" network; it involves all the health system specialists devoted to the diagnosis, the therapy and the follow-up of a RD. The Consortium is a multidisciplinary team operating throughout the Region composed of volunteer Physicians and Biologists that promotes periodical meetings to develop shared protocols. In 2008 the Specialist-Technical Committee for the Interregional RD Network approved the set up of the "Chiari and Syringomyelia Consortium" (CSC) with two specific objectives: to identify the shared diagnostic criteria and to develop the interdisciplinary diagnostic-therapeutic-assistance path (DTAP) to be used interregionally. Other objectives are: to define the prevalence of the pathologies (both symptomatic and asymptomatic, both in adults and children) and to improve collaboration between the patient Associations and the Physicians.

Idiopathic syringomyelia: retrospective case series, comprehensive review, and update on management.

OBJECT: A syrinx is a fluid-filled cavity within the spinal cord that can be an incidental finding or it can be accompanied by symptoms of pain and temperature insensitivity. Although it is most commonly associated with Chiari malformation Type I, the advancement of imaging techniques has resulted in more incidental idiopathic syringes that are not associated with Chiari, tumor, trauma, or postinfectious causes. The authors present a comprehensive review and management strategies for the idiopathic variant of syringomyelia. METHODS: The authors retrospectively identified 8 idiopathic cases of syringomyelia at their institution during the last 6 years. A PubMed/Medline literature review yielded an additional 38 articles. RESULTS: Two of the authors' patients underwent surgical treatment that included a combination of laminectomy, lysis of adhesions, duraplasty, and syrinx fenestration. The remaining 6 patients were treated conservatively and had neurologically stable outcomes. Review of the literature suggests that an etiology-driven approach is essential in the diagnosis and management of syringomyelia, although conservative management suffices for most cases. In particular, it is important to look at disturbances in CSF flow, as well as structural abnormalities including arachnoid webs, cysts, scars, and a diminutive posterior fossa. CONCLUSIONS: The precise etiology for idiopathic syringomyelia (IS) is still unclear, although conceptual advances have been made toward the overall understanding of the pathophysiology of IS. Various theories include the cerebellar piston theory, intramedullary pulse pressure theory, and increased spinal subarachnoid pressure. For most patients with IS, conservative management works well. Continued progression of symptoms, however, could be approached using decompressive strategies such as laminectomy, lysis of adhesions, and craniocervical decompression, depending on the level of pathology. Management for patients with progressive neurological dysfunction and the lack of flow disturbance is unclear, although syringosubarachnoid shunting can be considered.

Natural history of untreated syringomyelia in pediatric patients.

OBJECT: The natural history of syringomyelia in pediatric patients remains uncertain. Although symptomatic and operative cases of syringomyelia are well studied, there are fewer articles in the literature on the nonoperative syrinx and its clinical and radiological course. The purpose of this research was to analyze the natural history of untreated syringomyelia in pediatric patients presenting with minimal neurological symptoms. METHODS: A review of the neurosurgery database at British Columbia's Children's Hospital identified all pediatric patients (< 18 years of age) with syringes identified on MR imaging. Patients were included in this study if they had at least 2 MR images of the spine, at least 1 year apart, while receiving nonoperative treatment. Magnetic resonance imaging was used to determine changes in the size of the syrinx over time. Clinic notes were analyzed to establish demographic and clinical features and to determine any clinical changes over time. RESULTS: A total of 17 patients were included in the study. Symptoms at presentation were often mild and included limb numbness (3 cases), headaches (2 cases), mild sensory deficits (2 cases), mild motor deficits (3 cases), and intermittent incontinence (7 cases). The consultant neurosurgeon believed that the syrinx was not contributing to the symptoms in these 17 patients. The syrinx either remained unchanged (7 cases) or diminished in size (8 cases) in a total of 15 patients (88%). In the remaining 2 patients the authors noted an increase in syrinx size, in 1 of whom the clinical course also worsened. Both of these patients had a Chiari malformation and subsequently underwent craniocervical decompression. Overall, the mean change was -0.7 mm of maximal axial diameter (range -2.6 to +2.7 mm). Sixteen patients (94%) exhibited no worsening of symptoms over time. CONCLUSIONS: Syringomyelia often remains stable in patients receiving nonoperative treatment. However, given that 2 (12%) of 17 syringes in this series enlarged, it is likely appropriate to include periodic imaging in the follow-up of these cases.