Vascular Malformations of the Spinal Cord Treatment & Management
- Author: James S Harrop, MD; Chief Editor: Brian H Kopell, MD more...
Presently, no acceptable pharmacological means are available to treat spinal vascular malformations.
The use of glucocorticoids may improve the patient's neurologic function for a short period. These steroids decrease vasogenic edema, but they do not treat the underlying pathology of the disorder. Unfortunately, these medications have adverse long-term affects. The prolonged use of steroids is associated with adverse systemic effects, such as gastric ulceration, elevated blood glucose levels, and suppression of the immune system.
Each spinal vascular malformation is a unique lesion; therefore, an individualized treatment algorithm must be tailored to each patient. The present surgical treatment options include open surgical ligation or resection of the malformation, endovascular occlusion, spinal radiation, or a combination of these techniques.
Dural arteriovenous fistulas (AVFs), type 1, can be treated with either open or endovascular ligation. Both techniques yield excellent results, with occlusion rates reported as higher than 80%. The benefit of the endovascular technique is that it is less invasive. If the patient has multiple sites of fistula formation, open ligation is more appropriate because all feeding vessels may be ligated under direct vision. Open surgery is necessary if the arterial feeding vessel is impossible to access because of tortuous vascular anatomy or if the vessel supplies blood to healthy regions of the spinal cord.[4, 7, 8, 9, 10, 11]
Intradural AVMs (types 2-4) are typically best treated with endovascular surgery and, if required, open surgery and resection.
Treatment options are dictated by the location of the lesion, the patient's medical condition, and the risk-versus-benefit ratio. The most important factor in determining treatment options is the presence of intramedullary or extramedullary shunting. Malformations that are subpial in location are less likely to be cured. These are usually supplied by subcommissural branches of the anterior spinal artery (ASA). The role of partial embolization is not clear. Long-term clinical results in patients with symptomatic spinal AVMs have demonstrated a lower incidence of recurrent hemorrhage; this may have a role in difficult lesions. Lesions on the surface of the spinal cord that are supplied by circumferential branches of the ASA may be safely treated with either embolization or surgery.
The new generation of liquid embolic material and microcatheters has made interventional treatment of spinal AVMs safer, with better results.[12, 13] The goal of any intervention is to eliminate the shunt. Microcatheterization is of paramount necessity in achieving effective results. Delivery of embolic material to the nidus of the lesion reduces the arteriovenous malformation (AVM) and reduces the risk of inadvertent embolization of normal vessels.
Liquid embolic agents are the first choice for most spinal AVMs because they are the most likely to fill distal nidus and because they are associated with a low recanalization rate. The authors' agents of choice are n-butyl cyanoacrylate (n-BCA) and Onyx (ethylene vinyl alcohol copolymer). Embolization of lesions supplied by the ASA requires selective catheterization and deposition of embolic material. Permanent deficits due to embolizations in the ASA territory occur in up to 11% of patients.
The manipulation of viscosity of the liquid embolic as in the case of n-BCA or use of different viscosity Onyx (Onyx-18 versus Onyx-34) helps to ensure more precise deposition. Polymerization should occur in transit through the arteriovenous shunt. In higher-flow lesions, pharmacologically induced hypotension is used, typically with a mean arterial pressure of 50 mm Hg. With larger draining vessels, the Valsalva maneuver also helps to delay transit time.
When preoperative embolization is planned, polyvinyl alcohol microparticles (PVAs) are a reasonable choice of embolic material. They are also useful for embolization of type 2 AVMs. The advantages of PVA are that embolization may be performed at a more proximal location and that the size of particle can be determined depending on the size of the lesion and its collaterals. The goal of treatment with either agent is to provide distal occlusion of the nidus. Proximal occlusion results in collateral reconstitution, with little hope of cure.
Regardless of the choice of material used for embolization, all procedures should be performed under general anesthesia with neurophysiologic monitoring, depending on the location of the lesion. Somatosensory-evoked potentials (SSEPs) are very accurate in assessing spinal cord function. Motor-evoked potentials (MEPs) are also useful when a spinal AVM is supplied by the ASA.
The preoperative evaluation consists of a detailed neurologic examination, baseline urodynamic evaluation, and appropriate imaging studies that confirm the diagnosis of a vascular malformation. MRI of dural AVFs on the thoracolumbar junction usually shows serpiginous vessels in the intradural compartment, along with vasogenic edema in the spinal cord (see the images below). Intradural vascular spinal malformations appear as lesions in the spinal parenchyma.
Once the diagnosis is considered, the anatomy of the malformation can be further defined with spinal arteriography. Spinal arteriography illustrates the detailed anatomy with dynamic images, providing the surgical team the information necessary to decide the best treatment option.
Once the lesion has been defined and the surgical treatment plan (either endovascular, open surgical, or a combination of the two) is determined, the patient is taken to the operating room or endovascular suite. The procedure is performed with the patient under general anesthesia, with the use of neurophysiological monitoring. Intraoperative monitoring allows analysis of ischemia to the spinal cord so that normal vascular channels are not inadvertently permanently disturbed. Arteriography may be performed in the operating room, with either endovascular or an open technique to confirm closure of the fistula.
Recently, indocyanine green videoangiography has been used by some neurological surgery centers during the treatment of spinal dural AVFs. This new technology allows surgeons to view, in real time, the vasculature within the operating field to ensure the AVF has been obliterated.
The patient is awakened from anesthesia and taken to a monitored setting where serial neurologic examinations can be performed. With ligation of the dural AVF, most patients show neurologic improvement and can begin physical therapy. Improvement in neurologic examination findings may take several weeks. If arteriography was not performed in the operating room, it should be performed in the immediate postoperative period to document closure of the fistula.
Patients should be monitored with serial neurologic examinations and imaging studies in an outpatient setting to confirm closure of the fistula. With intradural lesions, a procedure is deemed successful based on intraoperative assessment of complete resection and a postoperative arteriogram that shows no arteriovenous shunting. If patients experience any worsening from their neurologic baseline, an appropriate evaluation with imaging studies is completed to rule out fistula recurrence.
Postoperative MRI findings do not necessarily correlate with clinical outcomes. It is not uncommon for spinal cord abnormalities to persist on MRIs for many months, even with successful treatment.
Risks of open surgical or endovascular treatment
See the list below:
Skin infection or cellulitis
Injury to nervous tissue, causing paralysis, bladder or bowel dysfunction, or sexual dysfunction
Chronic pain syndromes
Thrombosis of epidural veins and neurologic loss
Recurrence of fistula
Spinal cord infarction
Complications that result from open surgical ligation or resection
See the list below:
Infection of meninges (meningitis)
Cerebrospinal fluid leak
Complications that result from the endovascular technique
See the list below:
Pseudoaneurysms and thrombosis
Outcome and Prognosis
Patient outcome is directly related to neurologic function at the time of the surgical intervention. Patients who are able to ambulate when treated tend to remain ambulatory and may increase their strength with physical therapy. Patients who do not have antigravity strength in the lower extremities before treatment are unlikely to regain neurologic function to the point of ambulation. Patients who present with bowel or bladder dysfunction have a limited return of neurologic function.
Diagnosing these lesions early and providing appropriate treatment is important if patients are to achieve an optimal neurologic outcome.
Future and Controversies
MRI should be the first diagnostic modality performed when a spinal vascular malformation is suspected. If a lesion is found, spinal angiography is considered the criterion standard for optimal analysis of the angioarchitectural features. Embolization with a liquid embolic agent is the first-choice treatment for type 2-4 malformations, whereas surgery may be a better option for type 1 malformations. The prognosis of these lesions seems better than previously thought, especially with advances in endovascular techniques and new embolic agents that offer a high success rate with low morbidity.
Further advances in endovascular and microneurosurgical techniques will be made in the future. Advances in endovascular techniques and equipment should include smaller and more navigable catheters that can be manipulated through tortuous anatomy. The use of noninvasive techniques, such as stereotactic spinal radiosurgery, is presently being investigated.
Anson JA, Spetzler RF. Interventional neuroradiology for spinal pathology. Clin Neurosurg. 1992. 39:388-417. [Medline].
Patsalides A, Santillan A, Knopman J, et al. Endovascular management of spinal dural arteriovenous fistulas. J NeuroIntervent Surg. 2010. 3(1):80-84.
Krings T. Vascular Malformations of the Spine and Spinal Cord : Anatomy, Classification, Treatment. Klin Neuroradiol. 2010 Feb 28. [Medline].
Özkan N, Kreitschmann-Andermahr I, Goerike SL, Wrede KH, Kleist B, Stein KP, et al. Single center experience with treatment of spinal dural arteriovenous fistulas. Neurosurg Rev. 2015 Oct. 38 (4):683-92. [Medline].
Kendall BE, Loque V. Spinal epidural angiomatous malformations draining into intrathecal veins. Neuroradiology. 1977. 13:181-189.
Aadland TD, Thielen KR, Kaufmann TJ, et al. 3D C-arm conebeam CT angiography as an adjunct in the precise anatomic characterization of spinal dural arteriovenous fistulas. AJNR Am J Neuroradiol. 2010 Mar. 31(3):476-80. [Medline].
Lin N, Smith ER, Scott RM, Orbach DB. Safety of neuroangiography and embolization in children: complication analysis of 697 consecutive procedures in 394 patients. J Neurosurg Pediatr. 2015 Oct. 16 (4):432-8. [Medline].
Signorelli F, Della Pepa GM, Sabatino G, Marchese E, Maira G, Puca A, et al. Diagnosis and management of dural arteriovenous fistulas: a 10 years single-center experience. Clin Neurol Neurosurg. 2015 Jan. 128:123-9. [Medline].
Clark S, Powell G, Kandasamy J, Lee M, Nahser H, Pigott T. Spinal dural arteriovenous fistulas--presentation, management and outcome in a single neurosurgical institution. Br J Neurosurg. 2013 Aug. 27 (4):465-70. [Medline].
Kirsch M, Berg-Dammer E, Musahl C, Bäzner H, Kühne D, Henkes H. Endovascular management of spinal dural arteriovenous fistulas in 78 patients. Neuroradiology. 2013 Feb. 55 (3):337-43. [Medline].
Maimon S, Luckman Y, Strauss I. Spinal Dural Arteriovenous Fistula: A Review. Adv Tech Stand Neurosurg. 2016. 43:111-37. [Medline].
Warakaulle DR, Aviv RI, Niemann D, Molyneux AJ, Byrne JV, Teddy P. Embolisation of spinal dural arteriovenous fistulae with Onyx. Neuroradiology. 2003 Feb. 45(2):110-2. [Medline].
Corkill RA, Mitsos AP, Molyneux AJ. Embolization of spinal intramedullary arteriovenous malformations using the liquid embolic agent, Onyx: a single-center experience in a series of 17 patients. J Neurosurg Spine. 2007 Nov. 7(5):478-85. [Medline].
Veznedaroglu E, Nelson PK, Jabbour PM, Rosenwasser RH. Endovascular treatment of spinal cord arteriovenous malformations. Neurosurgery. 2006 Nov. 59(5 Suppl 3):S202-9; discussion S3-13. [Medline].
Schuette AJ, Cawley CM, Barrow DL. Indocyanine green videoangiography in the management of dural arteriovenous fistulae. Neurosurgery. 2010 Sep. 67(3):658-62; discussion 662. [Medline].
Kaufmann TJ, Morris JM, Saladino A, Mandrekar JN, Lanzino G. Magnetic resonance imaging findings in treated spinal dural arteriovenous fistulas: lack of correlation with clinical outcomes. J Neurosurg Spine. 2011 Apr. 14(4):548-54. [Medline].
Clarke MJ, Patrick TA, White JB, et al. Spinal extradural arteriovenous malformations with parenchymal drainage: venous drainage variability and implications in clinical manifestations. Neurosurg Focus. 2009 Jan. 26(1):E5. [Medline].
Cohen JE, Moscovici S, Itshayek E. The advantages of balloon assistance in endovascular embolization of spinal dural arteriovenous fistulas. J Clin Neurosci. 2013 Jan. 20(1):141-3. [Medline].
Criscuolo GR, Oldfield EH, Doppman JL. Reversible acute and subacute myelopathy in patients with dural arteriovenous fistulas. Foix-Alajouanine syndrome reconsidered. J Neurosurg. 1989 Mar. 70(3):354-9. [Medline].
da Costa L, Dehdashti AR, terBrugge KG. Spinal cord vascular shunts: spinal cord vascular malformations and dural arteriovenous fistulas. Neurosurg Focus. 2009 Jan. 26(1):E6. [Medline].
Fugate JE, Lanzino G, Rabinstein AA. Clinical presentation and prognostic factors of spinal dural arteriovenous fistulas: an overview. Neurosurg Focus. 2012 May. 32(5):E17. [Medline].
Heros RC. Foix-Alajouanine syndrome: what is it?. J Neurosurg. 2009 Nov. 111(5):900-1. [Medline].
Kenning TJ, Deshaies EM, Adamo MA, Waldman JB, Boulos AS. Onyx embolization of a thoracolumbar perimedullary spinal arteriovenous fistula in an infant presenting with subarachnoid and intraventricular hemorrhage. J Neurosurg Pediatr. 2009 Mar. 3(3):211-4. [Medline].
Krauss WE. Vascular anatomy of the spinal cord. Neurosurg Clin N Am. 1999 Jan. 10(1):9-15. [Medline].
Morgan MK. Outcome from treatment for spinal arteriovenous malformation. Neurosurg Clin N Am. 1999 Jan. 10(1):113-9. [Medline].
Morris JM. Imaging of dural arteriovenous fistula. Radiol Clin North Am. 2012 Jul. 50(4):823-39. [Medline].
Niimi Y, Berenstein A. Endovascular treatment of spinal vascular malformations. Neurosurg Clin N Am. 1999 Jan. 10(1):47-71. [Medline].
Niimi Y, Berenstein A, Setton A, Neophytides A. Embolization of spinal dural arteriovenous fistulae: results and follow-up. Neurosurgery. 1997 Apr. 40(4):675-82; discussion 682-3. [Medline].
Oldfield EH, Doppman JL. Spinal arteriovenous malformations. Clin Neurosurg. 1988. 34:161-83. [Medline].
Patsalides A, Knopman J, Santillan A, Tsiouris AJ, Riina H, Gobin YP. Endovascular treatment of spinal arteriovenous lesions: beyond the dural fistula. AJNR Am J Neuroradiol. 2011 May. 32(5):798-808. [Medline].
Rodesch G, Hurth M, Alvarez H, Ducot B, Tadie M, Lasjaunias P. Angio-architecture of spinal cord arteriovenous shunts at presentation. Clinical correlations in adults and children. The Bicêtre experience on 155 consecutive patients seen between 1981-1999. Acta Neurochir (Wien). 2004 Mar. 146(3):217-26; discussion 226-7. [Medline].
Rubin MN, Rabinstein AA. Vascular diseases of the spinal cord. Neurol Clin. 2013 Feb. 31(1):153-81. [Medline].
Ruiz-Juretschke F, Perez-Calvo JM, Castro E, et al. A single-center, long-term study of spinal dural arteriovenous fistulas with multidisciplinary treatment. J Clin Neurosci. 2011 Dec. 18(12):1662-6. [Medline].
Sato K, Terbrugge KG, Krings T. Asymptomatic spinal dural arteriovenous fistulas: pathomechanical considerations. J Neurosurg Spine. 2012 May. 16(5):441-6. [Medline].
Song JK, Vinuela F, Gobin YP, et al. Surgical and endovascular treatment of spinal dural arteriovenous fistulas: long-term disability assessment and prognostic factors. J Neurosurg. 2001 Apr. 94(2 Suppl):199-204. [Medline].
Symon L, Kuyama H, Kendall B. Dural arteriovenous malformations of the spine. Clinical features and surgical results in 55 cases. J Neurosurg. 1984 Feb. 60(2):238-47. [Medline].
Trierweiller AC, Peixe BC, Tezza R, Pereira VL, Pacheco W Jr, Bornia AC, et al. Measuring organizational effectiveness in information and communication technology companies using item response theory. Work. 2012. 41 Suppl 1:2795-802. [Medline].
Watson JC, Oldfield EH. The surgical management of spinal dural vascular malformations. Neurosurg Clin N Am. 1999 Jan. 10(1):73-87. [Medline].
Yamaguchi S, Eguchi K, Kiura Y, Takeda M, Nagayama T, Uchida H, et al. Multi-detector-row CT angiography as a preoperative evaluation for spinal arteriovenous fistulae. Neurosurg Rev. 2007 Oct. 30(4):321-6; discussion 327. [Medline].