Syringomyelia is an abnormal cystic collection of fluid, or syrinx, within the parenchyma of the spinal cord. Communicating syringomyelia is caused by enlargement of the central canal in continuity with the 4th ventricle, and is often associated with hydrocephalus.1Noncommunicating syringomyelia is caused by syrinx formation within the gray matter.2 However, magnetic resonance imaging (MRI) studies have shown that most collections are not in continuity with the 4th ventricle, and therefore the terms communicating and noncommunicating are falling out of favor.
Syringomyelia can be developmental or acquired. Posttraumatic syringomyelia that occurs as a complication of spinal cord injury has been covered in a separate template, and therefore will not be covered here.
Syringomyelia can be congenital or acquired. Most cases of congenital syringomyelia are associated with neurologic conditions, such as Chiari malformations; however, idiopathic and rare familial cases are described.3 Acquired syringomyelia can be secondary to spinal cord injury, arachnoiditis, inflammatory or infectious conditions, or neoplasms.
Epidemiology including risk factors and primary prevention
Children and young adults are most commonly affected by syringomyelia. Historical studies showed an overall prevalence of 9 per 100,000; however, the widespread use of MRI has increased detection. Most will have a Chiari I malformation, and another quarter will have a history of spinal cord trauma or arachnoiditis.1 Syringomyelia associated with Chiari malformations is most commonly cervical, whereas idiopathic cases may have a higher prevalence of thoracic lesions in children.4
It was historically believed that syrinx formation was the result of cerebrospinal fluid (CSF) being driven into the parenchyma of the spinal cord through persistent connections with the 4th ventricle or perivascular channels. Chiari I malformations affect the flow of CSF through the foramen magnum, resulting in altered fluid dynamics. Recent studies and theories, however, support the idea that the accumulations are at least partially because of impaired venous compliance leading to a build-up of extracellular fluid.5 Mass effect on neurons as well as chemical mediators, such as substance P, contribute to symptoms.6
Disease progression including natural history, disease phases or stages, disease trajectory (clinical features and presentation over time)
Symptomatic syringomyelia presents with progressive neurologic deterioration. Initial symptoms from Chiari I malformations typically become clinically evident in young adulthood, and it can take several years from symptom onset until diagnosis.2 With earlier diagnosis made by MRI, the coexistent syringomyelia is often detected before the classical symptoms are evident. In cases of idiopathic syringomyelia detected on imaging, patients are often asymptomatic or do not have symptoms directly attributable to a syrinx. In these patients, conservative treatment is often employed, and the syrinx typically stabilizes in size or resolves without becoming problematic.4
Specific secondary or associated conditions and complications
In children with syringomyelia associated with Chiari I malformations, about 30% will have progressive scoliosis. Syringomyelia and Chiari I malformations are now more commonly being found in the workup of scoliosis. A left-sided curve, back pain, or other atypical symptoms should prompt the practitioner to have a higher level of suspicion for nonidiopathic causes for scoliosis.7 Hydrocephalus may also be associated with syringomyelia.
2. ESSENTIALS OF ASSESSMENT
In some cases, presentation may be clinically silent for long periods. Patients with concomitant Chiari I malformations often present with symptoms due to the malformation before manifestations of the syrinx itself. These include headaches, clumsiness, inner ear dysfunction, altered facial sensations, ocular changes, dysarthria, and dysphagia. Symptoms from the syrinx itself include weakness, clumsiness, paresthesias, and dysethesias, which do not necessarily follow an expected anatomical pattern based on synrix location, and may be unlilateral. Unsteady gait, muscle atrophy, spasticity, urinary or fecal incontinence, or male impotence may also be described.5,8
The classical description of loss of pain and temperature sensation but preservation of light touch is rare. Nonmyotomal or nondermatomal motor and sensory defects are often asymmetric, as are altered reflexes.2 When associated with Chiari malformations, headache or neck pain can by exacerbated by maneuvers that increase CSF pressures, such as a Valsalva.1 Atrophy of intrinsic hand muscles or fasciculations may also be an early finding. Signs of myelopathy in the lower extremities, such as spasticity, can become evident as the disease progresses.
Patients with motor and sensory deficits should be assessed for strength, balance, bed mobility, transfer status, ambulatory or wheelchair mobility status, as well as their ability to bathe, dress, and groom. Because pain medications can affect cognition, assessment of school or work skills, driving skills, memory, safety awareness, attention, medication managment, and finance management should be undertaken. Coughing, hypoxia, or wet dysphonia are frank indicators for swallowing evaluation, but patient’s should be evaluated for silent aspiration.
The diagnosis of syringomyelia is made with a careful history and physical examination. Imaging, typically a contrast-enhanced MRI, confirms the diagnosis. Syringomyelia has been found as sequelae of spinal infections as well as in the setting of tuberculosis, and if clinical suspicion is high, testing for these causes is warranted. Testing for systemic inflammatory conditions may also be useful in certain cases with unclear etiology.
Prior to the advent of MRI, computed tomography (CT) myelography was used for diagnosis. Because of its less invasive nature, MRI is typically employed earlier in the work-up for Chiari malformations, scoliosis, and syringomyelia. This has led to a lower average age at diagnosis.7 MRI is the modality of choice; however, CT myelography can be used when MRI is unavailable or unsafe.
Supplemental assessment tools
Electromyographic (EMG) studies may be used early in the work-up of extremity pain, weakness, or sensory changes to determine their etiology. They may also be used to measure disease progression over time for patients being treated conservatively or postoperatively. More detailed imaging of the spinal column with plain radiographs or CT may help evaluate coexisting scoliosis.2
Early predictions of outcomes
Increased age and duration of symptoms at the time of surgical decompression have been shown to predict worse clinical outcomes for patients with a syrinx and Chiari malformation.9 Early decompression of Chiari I malformations may halt the progression or improve associated spinal deformities if caught at a young age.10 While symptoms may stabilize for some patients, progressive symptoms should be treated aggressively, because they can lead to increased morbidity and even death.2
Syringomyelia is most often associated with Chiari I malformations and posttraumatic causes. Less common etiologies include postinfectious and postinflammatory causes. Case reports of familial causes exist, but there are no clear environmental links to syringomyelia at this time.
Social role and social support system
Patients may require assistance with redefining their social roles as impairments worsen and more adaptive equipment is needed. Assistance should be provided for developing a support network of family, friends, clergy, social work, peer support, vocational rehabilitation, coordination with school and work staff, and respite programs.
Parents (or legal guardians) should be intimately involved in the decision-making process for pediatric patients. Delay in treatment once neurologic symptoms develop could result in poor outcomes.11,12
3. REHABILITATION MANAGEMENT AND TREATMENTS
Available or current treatment guidelines
There are no formal published treatment guidelines for nontraumatic syringomyelia. In general, current management is individualized to the patient’s symptoms.
At different disease stages
Nonoperative management may be considered for patients who are Chiari I patients with small 2 level syrinxes and who are asymptomatic or have relatively mild symptoms; however, they must be monitored regularly with MRI.8,11,13-15
Patients with new neurologic symptoms, mass lesions, worsening pain, expanding syrinxes, or increasing scoliosis should be referred for neurosurgical evaluation.11 Neurosurgical evaluation should occur before scoliosis surgery because of the increased risk of neurologic deterioration.11 Hydrocephalus should be shunted before considering surgery for syringomyelia.2
The goal of surgical treatment is to restore CSF flow. Neurosurgical approaches may include suboccipital decompression, duroplasty, laminectomy, tonsillar resection, removal of subarachnoid adhesions, shunting, cord untethering, syrinx fenestration, removal of tumor, infection, or arteriovenous malformation.11,13-15 Medical postoperative complications include aseptic or bacterial meningitis, deep venous thrombosis, urinary tract infection, and pneumonia.9 Therefore, standards of care should include infection prevention, venothromboembolism prophylaxis, early removal of indwelling catheters, and bladder assessment and adequate pulmonary hygiene.
Stable postoperative patients should receive physical therapy, occupational therapy, and speech therapy.13 Goals are to relieve pain, preserve range of motion, normalize tone, and improve balance, strength, swallow, phonation, respiration, fine and gross motor coordination, activities of daily living, and sitting balance. Psychosocial counseling may help with coping. Pain may be treated with nonsteroidal anti-inflammatory drugs, muscle relaxants, anticonvulsants, antidepressants, topical agents, or narcotics.13 Sympathetic blockades may be helpful.6 There is no evidence that spinal infusions or modalities (electric stimulation, heat, massage) are helpful.13 Although there are reports that chiropractic treatment may improve pain and posture in syringomyelia,16 this has not been validated and is not a current standard of practice.
Long-term complications can include shunt failure, catheter tip migration, and syrinx recurrence.15 If neurologic decline occurs, the patient should be referred back to neurosurgery.15
Coordination of care
Care should be coordinated between the primary care physician or pediatrician, physiatrist, rehabilitation nurses, neurosurgeon, orthopedic surgeon, pain specialist, psychiatrist, social worker, physical therapist, occupational therapist, speech-language pathologist, dietician, and third party payers. Community resources may include, but are not limited to, vocational rehabilitation, driver rehabilitation, support groups, sports programs, school programs, and legal and financial aid groups.
Patient & family education
Information for patients and families can be obtained from the Chiari & Syringomyelia Foundation or the American Syringomyelia & Chiari Alliance Project. Chiari Malformation and Syringomyelia–A Handbook for Patients and Their Families is available.17
There are no outcome measures specific to syringomyelia. Neurosurgical and orthopedic studies have looked at syrinx size, neurologic symptoms, pain symptoms, rate of scoliosis curve progression, and American Spinal Injury Association motor scores as outcome indicators.11,18 EMG and somatosensory evoked potentials may be used for monitoring postsurgical outcomes. Rehabilitation-based functional measures, such as the Functional Independence Measure, have not been studied.
Translation into practice: practice “pearls”/performance improvement in practice (PIPs)/changes in clinical practice behaviors and skills
The presence of syringomyelia requires life-long management. Delay in treatment once neurologic symptoms appear may result in poorer outcomes.11,12
4. CUTTING EDGE/EMERGING AND UNIQUE CONCEPTS AND PRACTICE
Cutting edge concepts and practice
Dynamic contrast-enhanced MRI technology enables viewing of spinal fluid pulsating within the syrinx, even before symptoms appear in syringomyelia.18
Exploration of the factors and their role in the development and progression of syringomyelia is researched in the following areas19:
- Role of genetic factors related to a Chiari I malformation.
- Learning the role of birth defects in the development of hindbrain malformations.
- Abnormal CSF flow that may contribute to the progression.
- Developing preventive treatment to stop the formation of birth defects.
- Role for the cardiovascular system, as evidenced by forceful downward movement of the CSF with heart beat.
- Improvement in surgical techniques.
5. GAPS IN THE EVIDENCE-BASED KNOWLEDGE
Gaps in the evidence-based knowledge
There are no evidence-based guidelines.
Surgery for the treatment of syringomyelia may not be successful over the long term in relieving symptoms. The role of shunting procedures is questioned, and more recently their placement is regarded as a last resort.19 Although the diagnosis is easily done today with the relatively common availability of MRI scanning, it is not that easy at times to decide what the optimal treatment strategy is for the individual patient. Considerable controversy still surrounds the management of hindbrain hernia and syringomyelia, and this debate is largely because of the uncharted natural history of the condition. Inevitably, any discussion of the management of syringomyelia involves intimately the management of Chiari I malformation.8 The unanswered questions are when do hindbrain hernia/Chiari I malformation and syringomyelia or recurrent syringomyelia or associated hydrocephalus need treatment and what are the best surgical procedures?8
1. Broadbill AR, Stoodley MA. Post-traumatic syringomyelia: a review. J Clin Neurosci. 2003;10:401-408.
2. Svircev JN, Little JW. Syringomyelia. In: Lin VW, Bono CM, Cardenas DD, et al, eds. Spinal Cord Medicine Principles and Practice. 2nd ed. New York, NY: Demos Medical Publishing; 2010:569-574.
3. Busis NA, Hochberg FH. Familial syringomyelia. J Neurol Neurosurg Psychiatry. 1985;48:936-938.
4. Magge SN, Smyth MD, Governale LS, et al. Idiopathic syrinx in the pediatric population: a combined center experience. J Neurosurg Pediatr. 2011;7:30-36.
5. Koyanagi I, Houkin K. Pathogenesis of syringomyelia associated with Chiari type 1 malformation: review of evidences and proposal of a new hypothesis. Neurosurg Rev. 2010;33:271-285.
6. Todor DR, Mu HT, Milhorat TH. Pain and syringomyelia: a review. Neurosurg Focus. 2000;8:11.
7. Steinbok P. Clinical features of Chiari I malformations. Childs Nerv Syst. 2004;20:329-331.
8. Sgouros S. Syringomyelia. In: Ellenbogen RG, Abdulrauf SI, Sekhar LN, eds. Principles of Neurological Surgery. 3rd ed. Saunders, Philadelphia PA; 2012:455-469.
9. Alfieri A, Giampietro P. Long-term results after posterior fossa decompression in syringomyelia with adult Chiari type 1 malformation. J Neurosurg Spine. 2012;17:381-387.
10. Eule JM, Erickson MA, O’Brien MF, et al. Chiari I malformation associated with syringomyelia and scoliosis. Spine. 2002;27:1451-1455.
11. Akhtar OH, Rowe DE. Syringomyelia-associated scoliosis with and without the Chiari I malformation. J Am Acad Orthop Surg. 2008;16:407-414.
12. Aghakhani, N, Parker F, David P, et al. Long-term follow-up of Chiari-related syringomyelia in adults: analysis of 157 surgically treated cases. Neurosurgery. 2009;64:308-315.
13. Fernandez AA, Guerrero AI, Martinez MI, et al. Malformations of the craniocervical junction (Chiari type I and syringomyelia: classification, diagnosis and treatment). BMC Musculoskelet Disord. 2009;10(Suppl 1):S1.
14. Sharma M, Coppa N, Sandhu FA. Syringomyelia: a review. Semin Spine Surg. 2006;18:180-184.
15. Roy AK, Slimack NP, Ganju A. Idiopathic syringomyelia: retrospective case series, comprehensive review, and update on management. Neurosurg Focus. 2011;31: E15.
16. Haas JW, Harrison DE, Harrison DD, et al. Conservative treatment of a patient with syringomyelia using chiropractic biophysics protocols. J Manipulative Physiol Ther. 2005;28:452.
17. American Syringomyelia & Chiari Alliance Project Web site. Available at: www.asap.org. Accessed May 5, 2013.
18. Mauer UM, Gottschalk A, Mueller C, et al. Standard and cardiac-gated phase-contrast magnetic resonance imaging in the clinical course of patients with Chiari malformation type I. Neurosurg Focus. 2011;31:E5.
19. Klekamp J. Treatment of syringomyelia related to nontraumatic arachnoid pathologies of the spinal canal. Neurosurgery. 2013;72:376-389; discussion 389.
Attenillo FJ, McGirt MJ, Gathinji M, et al. Outcome of Chiari-associated syringomyelia after hindbrain decompression in children: analysis of 49 consecutive cases. Neurosurgery. 2008;62:1307-1313.
Original Version of the Topic
Jean L. Nickels, MD, K. Rao Poduri, MD. Syringomyelia. 09/20/2013
Jean L. Nickels, MD
Nothing to Disclose
K. Rao Poduri, MD
Nothing to Disclose