Intramedullary Spinal Arteriovenous Malformations Research Articles

429 Intramedullary Spinal Arteriovenous Malformations—Definition of Two Distinct Subtypes

INTRODUCTION: Intramedullary spinal arteriovenous malformations (SpiAVM) are complex lesions. Due to their rarity, reports of their management and outcomes are limited. METHODS: Our neurovascular database was reviewed SpiAVMs between January 1986 and December 2021. Demographic, clinical, radiographic, and outcome data were obtained. Eccentric SpiAVMs were defined as those with a significant portion presenting through the pia mater into the subarachnoid space, with large vessels coursing outside the parenchyma. Concentric SpiAVMs were defined as those embedded within the spinal cord parenchyma, not presenting to pia mater, and well circumscribed. RESULTS: Fifty-nine patients (mean [SD] age, 34 [15] years; female sex, 34) were identified. Patients exhibited myelopathy (88%), including pain (51%), paresis (88%), sensory deficits (46%), and bowel and bladder dysfunction (46%). Twenty-seven patients (46%) presented with hemorrhage. Forty-nine percent of lesions were located in the cervical spine and 51% in the thoracic spine. Thirty-five lesions (59%) were previously embolized. Twenty-eight patients (51%) were classified as eccentric and 27 (49%) as concentric SpiAVMs. Postoperative outcomes were similar with no significant differences (improved, 8/18 [44%] vs. 9/17 [53%]; unchanged, 8/18 [44%] vs. 7/17 [41%]; worse, 2/18 [11%] vs. 1/17 [6%]). Retreatment rates were not significantly different between both subtypes (eccentric, 9/28 [32%]; concentric, 6/27 [22%]). Eccentric and concentric SpiAVMs were associated with similar rates of complete resection (eccentric, 14/26 [54%], concentric, 18/26 [69%]). Of 55 classifiable lesions, 4 (7%) were determined to have a mixed phenotype, harboring characteristics of eccentric and concentric SpiAVMs. CONCLUSIONS: Intramedullary AVMs may cause significant symptoms. The eccentric and concentric subtypes have different angioarchitecture and outcomes. While complete resection is usually the preferred surgical objective, eccentric SpiAVMs are amenable to the pial resection that may achieve angiographic obliteration without complete resection.

Transvenous embolization of conus spinal arteriovenous malformation: illustrative case

Spinal arteriovenous malformations (AVMs) are the most challenging spinal vascular malformations. Endovascular transarterial embolization of spinal AVM has been well described. However, transvenous embolization has not been previously reported. In this case report, the authors describe transvenous embolization of a recurrent intramedullary/conus spinal AVM that was previously deemed unamenable to endovascular therapy. A 30-year-old female presented with debilitating lumbar back pain and was found to have an intramedullary spinal AVM at the level of the conus medullaris. Initially, the AVM was treated with endovascular arterial embolization and subsequently with microsurgical resection. However, on follow-up angiography, the AVM had recurred. Further arterial embolization was deemed not possible because of anatomical challenges. After careful consideration, endovascular transvenous embolization was performed with successful occlusion of the AVM nidus. Transvenous embolization is an alternative route for endovascular treatment of spinal AVMs that have an accessible single draining vein.

Differentiation between spinal dural arteriovenous fistulas, intramedullary spinal arteriovenous malformations, and perimedullary arteriovenous fistulas through magnetic resonance imaging

Differentiation between spinal dural arteriovenous fistulas, intramedullary spinal arteriovenous malformations, and perimedullary arteriovenous fistulas through magnetic resonance imaging

Stereotactic Radiotherapy for Intramedullary Spinal Arteriovenous Malformations.

IntroductionPreliminary results of stereotactic radiotherapy (SRT) for spinal arteriovenous malformation (AVM) in five cases are presented. MethodsTwo cases were male and three were female. Their median age was 32 years (range: 23 to 54 years). The spinal intramedullary AVMs were located in the cervical spine in three and in the thoracic spine in two. SRT with 20 Gy in four fractions was delivered to the nidus in every case.ResultsAt the end of the median follow-up period of 5.5 years (range: 3 to 8.5 years), the neurological symptoms and signs were improved or unchanged as compared with before treatment, although a temporary adverse effect developed between a half year and one year after SRT in one case. The nidi were obliterated five and a half years after SRT in one case and three years after SRT in one. In the other three cases, the nidi were unchanged.ConclusionSRT with 20 Gy in four fractions was thought to be a safe treatment, though this study dealt with only a small number of patients with a short-term follow-up period.

Microsurgical management and outcomes of intramedullary spinal arteriovenous malformations: a report of 14 cases

Objective: To investigate the clinical features, microsurgical management and outcomes of intramedullary spinal arteriovenous malformations (AVM). Methods: A series of 14 patients (10 male, 4 female; mean age (39.1±17.2) years ranged from 16 to 72 years) with intramedullary spinal AVM who underwent microsurgical treatment from November 2008 to April 2015 in Department of Neurosurgery at Beijing Tiantan Hospital were retrospectively reviewed. The location of the AVM included cervical (n=6), thoracic (n=3), cervicothoracic (n=2), and conus medullaris (n=3). The patients underwent microsurgery via the posterior myelotomy, indocyanine green fluorescence angiography(ICG)was performed to detect the feeding arteries and draining veins. After the lesions were removed, ICG was performed again to judge whether the AVM was resected completely. Results: Fourteen patients underwent resection of intramedullary spinal AVM in this period, total AVM resection was achieved in 12 patients and subtotal in 2 patients. The amount of bleeding was (178.6±141.0) ml ranged from 100 to 600 ml intraoperatively and no one received blood transfusion. Clinically, 13 patients improved, 1 patient worsened. Twelve patients got functionally improved, 2 patients remained unchanged during the long-term follow-up period ranged from 11 to 84 months, with a mean time of (60.9±20.4) months. Conclusions: Intramedullary spinal AVM is an extremely rare spinal vascular disease. Microsurgical treatment can safely resect the lesions with satisfactory clinical outcomes and reduce spine function deterioration.

Stereotactic radiosurgery as a feasible treatment for intramedullary spinal arteriovenous malformations: a single-center observation.

Spinal cord intramedullary arteriovenous malformations are rare. For patients suffering from either hemorrhage or myelopathy, surgical or endovascular interventions are indicated. However, complete eradication of the nidus is often difficult because of its intramedullary location and complex angioarchitecture. In this report, we evaluate the feasibility and safety of stereotactic radiosurgery as a treatment modality for intramedullary spinal arteriovenous malformations (AVMs). Between 2010 and 2014, we performed stereotactic radiosurgery to treat four patients with intramedullary AVM and one with spinal arteriovenous metameric syndrome (one woman and four men; age range, 31-66years). Three patients presented with myelopathy, and two suffered hemorrhages. Nidi were located in the cervical (three cases) and thoracic (two cases) spinal cord regions. Based on the angioarchitecture, surgery and endovascular embolization were indicated. When both modalities were deemed hazardous, radiosurgery using CyberKnife™ was offered. Radiation using marginal doses of 18Gy was administered in three fractions. The mean follow-up period was 37.2months (range, 16-62months). After treatment, two of the three patients with myelopathy experienced either improvement or stabilization of their symptoms and one experienced worsening of dysesthesia. In two patients with hemorrhage, symptoms improved in one and remained stable in the other. No further hemorrhagic episodes were evident during follow-up. Follow-up angiograms showed marked shrinkage of the nidus located in the thoracic spinal cord in one case and angiographic stabilization in the others. As a treatment modality for intramedullary AVMs, CyberKnife™ is safe and can be considered when surgery or endovascular therapy is not indicated. To determine optimum radiation doses and protocols for treating spinal AVMs, further studies with more patients and long-term follow-up are required.

Microsurgical resection of an intramedullary glomus arteriovenous malformation in the high cervical spinal cord: retrograde dissection techniques of the nidus located between spinal tracts.

Spinal intramedullary arteriovenous malformations (AVMs) fed by an anterior spinal artery are surgically challenging vascular lesions. We herein presented microsurgical resection techniques for an intramedullary glomus AVM located in the lateral part of the high cervical spinal cord with an operative video. These techniques included (1) a lateral suboccipital approach via cervical hemilaminectomy in the lateral position; (2) retrograde dissection of the AVM located between the spinal tracts; (3) coagulation and division of multiple narrow sulcal branches of the anterior spinal artery. Patients who underwent these techniques achieved good outcomes with minimal bleeding and morbidity.

Concomitant intramedullary arteriovenous malformation and a vertebral hemangioma of cervical spine discovered by a pathologic fracture during bicycle accident

Spinal intramedullary arteriovenous malformations are uncommon and a challenging type of neurosurgical entities. They are rarely located to cervical segment. On the other hand, although hemangiomas are relatively common bone tumors, cervical involvement is again rare and clinically significant ones are infrequent. A 14 year-old-male patient referred to an academic tertiary care unit and presented with neck pain and left hand weakness. Neurological examination revealed motor strength deficit at intrinsic muscles and hyperesthesia at the left hand. Furthermore the pathological reflexes were positive on the left hand side. Imaging studies showed compression fracture, lytic changes resembling a hemangioma at C7 vertebra, and also an intramedullary vascular pathology at C5-6 level which was shown to be an intradural-intramedullary arteriovenous malformation (AVM) on digital subtraction angiography. Based on neurological and radiological findings, the decision was to treat the patient. After embolization of the AVM, the neurological condition of the patient deteriorated and immediate MRI scan of the cervical spine revealed edema of the spinal cord at the C5-6 level. Thus an emergent surgery was performed and C5-6-7 laminectomies with C5-T2 posterior fixation and arthrodesis were implemented. A second stage operation was carried out as C7 corpectomy with a distractable titanium cage 2 weeks after initial surgery. A follow-up evaluation at five years revealed 4/5 motor strength on his left intrinsic hand muscles and mild hyperactive deep tendon reflexes. Imaging studies at the postoperative period showed stable placement of the construct and no evidence of contrast enhancement at the C5-6 level inside the spinal cord. A rare case of multiple pathologies affecting the cervical spine, coincidentally diagnosed after a pathological fracture during a bicycle accident as vertebral hemangioma and intradural-intramedullary AVM that was successfully treated with early detection, have been presented. One should assess such patients under multidisciplinary fashion and treat on a case-by-case basis for achieving the best results in patient care.

Endovascular Treatment of Spinal Vascular Lesion in Japan: Japanese Registry of Neuroendovascular Therapy (JR-NET) and JR-NET2

A subgroup analysis of spinal vascular lesions in the Japanese Registry of Neuroendovascular Therapy (JR-NET) and JR-NET2, retrospective registry studies conducted in 2005–2009, was performed to understand the current status of treatment in Japan. Of 201 spinal lesions enrolled, 98 analyzable cases of spinal dural arteriovenous fistula (SDAVF), 43 of spinal perimedullary arteriovenous fistula (SPAVF), and 23 of spinal intramedullary arteriovenous malformation (SIAVM) were assessed. Treatment was radical in the majority (83.6%) of SDAVF, palliative in the majority (70.6%) of SIAVM, and radical and palliative in a similar number of cases of SPAVF. Total occlusion was achieved in 26 (54.2%) SDAVF cases, 9 (29.0%) SPAVF, and 4 (23.5%) SIAVM. Treatment-related complications occurred in 3 (3.1%) SDAVF cases, 7 (16.3%) SPAVF, and 1 (4.3%) SIAVM. Post-treatment neurological improvement was achieved in 49 (50.0%) of SDAVF cases, 15 (34.9%) SPAVF, and 5 (21.7%) SIAVM. The modified Rankin Scale (mRS) of 0, 1, or 2 on postoperative day 30, the primary endpoint, was achieved in 62 (63.3%) SDAVF cases, 26 (60.5%) SPAVF, and 12 (52.2%) SIAVM. The mRS of 0–2 on postoperative day 30 was correlated with pre-symptomatic mRS of 0–2 [P < 0.0001, odds ratio (OR): 42.88, 95% confidence interval (CI): 14.83–123.97] and postoperative neurological improvement (P = 0.046, OR: 2.57, 95% CI: 1.02–6.48). In Japan, endovascular treatment of spinal vascular lesions was administered safely. Good mRS on postoperative day 30 was highly correlated with good pre-symptomatic mRS, suggesting necessity of early diagnosis and treatment.

Embolization of spinal intramedullary arteriovenous malformations using the liquid embolic agent, Onyx: a single-center experience in a series of 17 patients

The aim of this study was to analyze the endovascular treatment results of using the Onyx liquid embolic system for spinal intramedullary arteriovenous malformations (AVMs). The clinical and radiological records of 17 patients with symptomatic spinal intramedullary AVMs treated exclusively by embolization with Onyx between 1999 and 2003 were retrospectively reviewed. There were 12 females and five males in the patient series (mean age 29 years). Four of these AVMs were located in the cervical spine, eight in the thoracic spine, and five in the lumbar spine. The clinical presentation of these AVMs included upper motor neuron signs and symptoms, and hemorrhage was the initial presentation in 12 patients. Neurological and functional evaluation was performed before and after treatment with Onyx in all patients. Thirteen patients underwent a single endovascular treatment and four patients underwent two endovascular treatments (average 1.23 sessions per patient). Intraprocedural complications occurred on two occasions without neurological consequences. The mean follow-up duration was 24.3 months. Angiographic outcomes included total AVM obliteration in six patients (37.5%), subtotal obliteration in five patients (31.25%), and partial obliteration in five patients (31.25%). Improvement in neurological and/or functional status was noted in 14 patients, resulting in an 82% rate of overall good clinical outcome. Embolization using the Onyx system is a promising treatment method for spinal vascular malformations, even for challenging intramedullary AVMs. Larger studies with longer follow-up durations will further enhance our knowledge on the safety and efficacy of this relatively new liquid embolic agent.

Embolization of spinal intramedullary arteriovenous malformations using the liquid embolic agent, Onyx: a single-center experience in a series of 17 patients

Embolization of spinal intramedullary arteriovenous malformations using the liquid embolic agent, Onyx: a single-center experience in a series of 17 patients

Spinal Arteriovenous Malformation Associated with a Radicular Arteriovenous Fistula Suggested a Metameric Disease

A spinal intramedullary arteriovenous malformation (AVM) associated with a radicular arteriovenous fistula (AVF) is reported. The patient had mild myelopathy and low back pain. Spinal angiography revealed the AVM fed by the anterior spinal artery via left T10, T11 and right L1 radiculomedullary arteries and the radiculopial arteries of left L1, L2 and right T11, L3 levels and the radicular AVF at the left L4 level. There were three radiculomedullary arteries within four levels in our case. This spinal AVM associated with a radicular AVF is considered a genetic nonhereditary lesion with metameric link.

Treatment of Intramedullary Arteriovenous Malformations of the Spinal Cord

We retrospectively reviewed our treatment results for spinal intramedullary arteriovenous malformations (AVMs). Fifteen consecutive patients were included in this syudy. Five patient underwent particulate embolization. Surgery was performed in ten patients (including two patient who were treated embolization initially). Five patients, at the beginning of our experience, underwent radical excision of the nidus via the posterior myelotomy. Recent five patients underwent interruption of the feeding pedicles on the surface of the spinal cord. Especially when arteriovenous fistulas (AVFs) or aneurysms were demonstrated, accurate obliteration of them were performed. Four patients, including two with residual AVM after the surgery, underwent irradiation therapy. Anatomically, four AVMs disappeared completely and the other 11 patients have a residual lesions after the treatment. Clinically, three patients improved, six remained unchanged, and six worsened. The causes of neurological deterioration after the treatment were technical complication of embolization in one patient and surgical manipulation in five. There was no patient who experienced hemorrhage during the followup period ranged from 6 months to 17 years, with a mean of 7.5 years. In conclusion, particulate embolization should be considered as the first choice of treatment if feasible. Surgical treatment is indicated for the dangerous anatomical features such as AVFs or aneurysms.

Hemodynamic evaluation of spinal arteriovenous malformations before and after embolization--preliminary report.

This preliminary study investigated local hemodynamic changes in intramedullary spinal arteriovenous malformation (AVM) before and after embolization. 99mTcO4- was injected into the anterior spinal artery feeding the AVM via a Tracker-10 or MAGIC microcatheter. Time-dependent radioisotope images were sequentially obtained in the anteroposterior plane every 0.2 sec before and just after embolization. Local mean transit time (MTT) was then calculated for both the nidus and draining vein and compared before and after embolization. Prior to embolization, MTTs in the nidus and in the draining vein were 1.84 +/- 0.62 (mean +/- SD) and 2.80 +/- 0.69 sec for the five patients, respectively. MTTs in both the nidus and the draining vein were significantly prolonged after embolization to 3.32 +/- 1.14 and 4.90 +/- 0.93 sec, respectively (p < 0.02 and p < 0.005, respectively). In vivo measurements of local hemodynamic changes in the spinal cord during the treatment of spinal AVMs could be achieved. This method may allow investigation of the hemodynamic mechanisms which induce ischemic symptoms in patients with spinal AVM.

Embolization of Intramedullary Spinal Arteriovenous Malformation Fed by the Anterior Spinal Artery with Monitoring of the Corticospinal Motor Evoked Potential

Intramedullary spina AVMs fed by the anterior spinal artery cannot be embolized without risking unacceptable motor deficits, since the feeding arteries may supply the corticospinal tract (CST). An 8-year-old boy underwent successful embolization of such an AVM under general anesthesia using intermittent infusion of embolic material with monitoring of the CST integrity with the corticospinal motor evoked potential (MEP). This case illustrates the value of corticospinal MEP monitoring during therapeutic procedures under general anesthesia which risk interrupting the blood supply to the CST.