Spinal Cord Arteriovenous Fistulas Research Articles

Predictive Factors of the Management of Spinal Cord Arteriovenous Fistulas.

Spinal cord arteriovenous fistulas are rare cause of progressive myelopathy. The predictive factors of their outcome after endovascular or surgical treatment are still controversial. Twenty patients were diagnosed with spinal arteriovenous fistulas; 13 of them had dural and 7 had perimedullary fistulas (1 Dorsal and 6 Ventral). Surgery, endovascular or both treatments were used. Ten of the 13 patients in the dural group were surgically treated, while 2 were managed by embolization and one combined. Seven patients improved, while 6 patients showed stationary clinical course after intervention. Five patients in the perimedullary group were embolized with clinical improvement, 1 patient refused intervention, and 1 patient had surgery. Clinical improvement was significantly correlated to the duration of symptoms before intervention (p=0.012), and preoperative neurological condition (p=0.001). No significant correlation was found with age, anatomic level of the fistula, fistula type, and type of intervention. Microsurgery was preferred for dural and dorsally located perimedullary fistula, while embolization was preferred for ventrally located ones. Clinical improvement was significantly correlated with early intervention and preoperative neurological condition of the patient. Age of the patient, fistula type, fistula location, and type of intervention did not show significant relation to the outcome. Patients could benefit from intervention even if they present with poor neurological condition.

Time-resolved contrast-enhanced MR angiography of spinal vascular malformations.

The diagnosis of spinal vascular malformations may be challenging on conventional MR imaging because neither the location of the signal abnormality in the spinal cord nor the level of the abnormal flow voids correlates with the level of the fistula. We conducted a retrospective evaluation of the utility of using a time-resolved imaging of contrast kinetics sequence in the diagnosis, characterization, and localization of spinal vascular malformations, comparing it with the criterion standard of spinal DSA. Fifty-five consecutive patients with a suspected diagnosis of spinal vascular malformation underwent time-resolved imaging of contrast kinetics followed by spinal DSA. All scans were performed on a 1.5T scanner by using a standard 8-channel spine coil and were reported by a neuroradiologist before the DSA was performed. Forty-seven lesions were confirmed on time-resolved imaging of contrast kinetics and classified as spinal dural arteriovenous fistulas (n = 33, with 1 patient having a type Ib fistula), perimedullary spinal cord arteriovenous fistulas (n = 10), and intramedullary arteriovenous malformations (n = 3). One patient had an extradural spinal vascular malformation. Time-resolved imaging of contrast kinetics identified the location of the arterial feeder to within 1 vertebral level in 27/33 patients (81.8%) with spinal dural arteriovenous fistulas and correctly predicted the side in 22/33 (66.6%) patients. Perimedullary spinal cord arteriovenous fistulas were erroneously considered to represent spinal dural arteriovenous fistulas before spinal DSA. The anatomy of the arterial supply to intramedullary arteriovenous malformations was also poorly characterized on time-resolved contrast-enhanced MR angiography. It has been our experience that time-resolved imaging of contrast kinetics is a useful confirmatory tool when a spinal vascular malformation is suspected on the basis of clinical and conventional MR imaging findings. As experience with the technique grows and sequences are refined, it may be possible to rely on time-resolved imaging of contrast kinetics as a screening tool for the diagnosis of spinal vascular malformations.

Allergic shock and death associated with protamine administration in a diabetic patient

Background: Insulin is used to treat patients with both type 1 and type 2 diabetes mellitus. Allergic reac- tions to insulin might be triggered by insulin itself or inactive ingredients in the insulin formulation, includ- ing proteins such as protamine in neutral protamine Hagedorn (NPH) insulin. The use of highly purified animal insulin and human recombinant insulin has reduced the incidence of anaphylactic reactions to insulin from ~30% to <1%. Objective: We report a case of fatal allergic shock after the administration of protamine in a patient with a history of allergy to fish and a protamine-containing insulin. Case summary: A 72-year-old Chinese male patient (height, 175 cm; weight, 80 kg) with a history of diabetes and progressive limb weakness was diagnosed with spinal vascular malformations after admission to the Xuan Wu Hospital of Capital Medical University, Beijing, People's Republic of China. He underwent epidural spinal cord arteriovenous fistula embolization with a liquid embolic agent (ethylene vinyl alcohol copolymer) after spinal cord angiography. During the operation, heparin was infused every hour with 6250, 2500, 2500, and 1250 IU, respectively. The last dose of heparin was administered ~10 minutes before the opera- tion was completed. This was followed by the admin-istration of protamine to neutralize the remaining heparin in the patient's body. Blurry vision and dizziness 5 minutes after protamine administration were followed by pruritus and hives over his neck and face. Oxygen was administered and 10 mg of dexamethasone with 2 mg of epinephrine was injected. The patient's heart rate dropped, his blood pressure decreased, and his arterial oxygen saturation (SaO 2) declined progressively. About 10 minutes after the administration of protamine sulfate, the patient developed bradycardic arrest. Cardiopulmonary resuscitation efforts were undertaken and the patient was administered epinephrine 2 mg IV, atropine 0.5 mg IV, and subsequently, intravenous dopamine (50 mg/h). Ten minutes later, the patient's heart rate gradually increased, but blood pressure fluctuated, and SaO 2 ranged from 90% to 100%. Despite the initial response, the patient lost consciousness and heart rate declined progressively within 5 hours. Vasoactive agents including dopamine, norepinephrine, and adrenaline were administered. After all these measures proved inef- fectual, the patient died. It was later determined that the patient had a history of allergic reactions to fish as well as to a premixed insulin that contained soluble human insulin 30% and low-protein intensive insulin zinc 70% (NPH). The Naranjo adverse drug reaction probability scale score for the association of protamine with the allergic reaction was 4, suggesting a possible relationship. Conclusion: This case report highlights a preventable fatal allergic reaction possibly associated with protamine administration in a patient with a history of allergy to a protamine-containing insulin.

Spinal intradural arteriovenous fistula with unusual presentation: case report and literature review

The authors present their experience with a Cervical Spinal intradural arteriovenous fistula (AVF) with unusual clinical presentation in a pediatric patient and review of the international literature on this condition. A 5-year-old girl was found by her parents in bed screaming and talking inappropriately. Later on, she calmed down and complained of occipital, back and neck pain. She was admitted to the CHEO-ICU for work up and observation. The admission head CT scan showed evidence of SAH. Brain MRI showed blood in the third and fourth ventricles. MRA showed a C2 vascular lesion consistent with spinal cord AVF. Conventional angiogram was done which confirmed the AVF fed by a posterior medullary artery originating from the left vertebral artery. An attempt to embolize the AVF with glue was made but proved to be unsuccessful. On December 4, 2002, direct surgery on the AVF was performed, through a midline posterior approach (C2-C3 laminectomies) and microsurgical technique a complete excision of the intradural extramedullary AVF was achieved. The postoperative course was uneventful and the patient remained neurologically intact. Post-operative angiography confirmed complete excision of the AVF. The rarity of a pediatric spinal AVF presenting with spontaneous Intracranial SAH, makes this case very peculiar. This is the first reported pediatric case of cervical cord AVF with this clinical presentation found in the literature.

Spinal arteriovenous shunts presenting before 2 years of age: analysis of 13 cases

A minority of patients with spinal arteriovenous malformations (SAVM) are symptomatic as neonates or infants. We analyzed the clinical and anatomic factors associated with this early presentation, and reviewed our experience in treating patients with these lesions. A retrospective review of clinical records and imaging studies was performed for patients with SAVM who presented at less than 2 years of age and who were examined by the diagnostic and interventional neuroradiology service at our institution. Clinical, imaging and treatment data had been entered prospectively into a department database. Thirteen patients were identified that had SAVMs that were either diagnosed or that became symptomatic before 2 years of age (nine boys, four girls). These represented 13% of the SAVM seen during the same period of time. The mean age at presentation was 6.9+/-6.4 months. Of the 13 patients, 11 had neurologic symptoms attributable to the spinal lesion. The presentation was nonhemorrhagic in ten patients and associated with hemorrhage in three. Ten lesions were fistulas [spinal cord arteriovenous fistulas (SCAVFs)] (77%); two were of the nidus type of malformation. There were syndromic associations in eight patients: hereditary hemorrhagic telangectasia (HHT) in six patients, all but one of these lesions were intradural high-flow perimedullary SCAVFs (46% of overall SAVM and 56% of SCAVF), and spinal arteriovenous metameric syndrome in two patients. One patient had Hirschprung's anomaly. Eight patients underwent endovascular treatment alone, one had surgery and embolization, and four were not treated. In all patients undergoing embolization, n-butyl cyanoacrylate liquid adhesive was used. Of those patients who underwent endovascular treatment, the lesion was completely obliterated in 7 and a 90% reduction in nidal size was achieved in the remaining 2. There was one treatment complication (infection) which resolved with medical therapy. No procedure-related permanent morbidity or mortality was seen. Follow-up data were available (mean 31.4 months) in ten patients (nine treated). All treated patients were either stable or improved, with none showing further deterioration following treatment. Factors associated with early presentation in neonates and infants with spinal arteriovenous shunts include the presence of high-flow, solitary fistulas and HHT. Specifically, the presence of SCAVF in a child less than 2 years of age is highly suggestive of HHT. Despite the aggressive nature of these lesions, many are amenable to endovascular treatment, and this is associated with a favorable posttreatment course in most cases.

Spinal Cord Intradural Arteriovenous Fistulae: Anatomic, Clinical, and Therapeutic Considerations in a Series of 32 Consecutive Patients Seen between 1981 and 2000 with Emphasis on Endovascular Therapy

To review our series of intradural spinal cord arteriovenous fistulas (SCAVFs), analyzing symptoms and related angioarchitecture, and to study the morphological and clinical results of embolization. Thirty-two SCAVFs (in 22 adults and 10 children) were treated between 1981 and 2000. These lesions were classified as microarteriovenous fistulas (mAVFs) or macroarteriovenous fistulas (MAVFs) according to shunt morphology. Location, architecture, presenting symptoms, and age group were detailed. The selection of patients for endovascular versus surgical treatments was analyzed, as were the anatomic and clinical results obtained by embolization with n-butylcyanoacrylate. Clinical status was evaluated according to the Karnofsky Performance Scale score. Ten SCAVFs were found in the pediatric population (four mAVFs and six MAVFs). All four mAVFs presented with acute symptoms. Three mAVFs (two cervical and one thoracic) presented hematomyelia; in one patient with a thoracic AVF, subarachnoid hemorrhage was suspected. All six MAVFs were located in the thoracolumbar cord (five associated with hereditary hemorrhagic telangiectasias). Four of the six MAVFs presented with hemorrhage. In the adult population, there were 21 mAVFS (95%) and one MAVF (5%). Only two mAVFs were found in the cervical cord, all other shunts affecting the thoracolumbar region. Hemorrhage was present in 6 of the 22 cases seen in adults (27%). The symptoms of SCAVFs did not differ from those found in spinal cord arteriovenous shunts of nidus type. Pial venous reflux and congestion were the most frequently encountered features in both the adult and pediatric groups. Arterial aneurysms (different from false aneurysms) were not found in association with hemorrhagic presentation of SCAVFs. Mean follow-up in our series was 3.3 years. Of the MAVFs, 86% were embolized, with 67% cured. The others had more than 75% occlusion. All patients followed up improved significantly. Of the mAVFs, 48% were treated endovascularly. Successful embolization was performed in 75% of patients. One patient was not embolized because of vasospasm, whereas 67% percent of mAVFs were completely occluded, 22% were more than 90% occluded, and 11% were 75% occluded. Complementary surgery was deemed unnecessary. All patients with mAVFs improved significantly at follow-up. Transient complications occurred in 22% of all patients, with no permanent morbidity or mortality. No patient bled or rebled after embolization. Thirty-six percent of mAVFs were operated on because of anticipated technical difficulties for endovascular approach or distal localization of the shunt. Endovascular treatment of SCAVFs stabilizes, normalizes, or improves neurological symptoms in all patients at long-term follow-up, with no bleeds or rebleeds. Embolization of SCAVFs with glue is a safe treatment that compares favorably with other approaches and significantly improves the poor natural history of the disease.

Split cord malformation with associated Type IV spinal cord perimedullary arteriovenous fistula

The authors describe the case of a 62-year-old woman with a Type II split cord malformation (SCM). At the initial time of workup, the authors observed an associated Klippel-Feil deformity at the level of the SCM and a low-lying conus medullaris; however, they discovered an associated Type IV perimedullary spinal cord arteriovenous fistula (AVF) only after the patient continued to deteriorate following a spinal cord untethering procedure. Although prominent blood vessels have been reported within the median cleft of SCMs, an angiographically and surgically proven perimedullary AVF has not previously been described. The potential coexistence of SCM and perimedullary AVF has significant clinical implications and its recognition is critically important prior to surgical treatment.

Metachronous Multiplicity of Spinal Cord Arteriovenous Fistula and Spinal Dural AVF in a Patient with Hereditary Haemorrhagic Telangiectasia

HHT (Hereditary Haemorrhagic Telangiectasia or Rendu Osler Weber disease) is a known autosomal dominant dysplasia. The first clinical presentation of HHT in a child may be a cerebral or spinal AVM. We present the case of a young boy with HHT who had a previous spinal cord AVF treated by surgical obliteration and then presented with a spinal dural AVF nine months later. This patient had surgical obliteration of a spinal cord perimedullary AVF and subsequently developed a new spinal dural AVF at a different level. The diagnosis was made by spinal MR imaging and spinal angiography.

Spinal Cord and Spinal Dural Arteriovenous Fistulas and Intradural Calcification Case Report

A patient had 3 episodes of spinal subarachnoid hemorrhage over 23 years and after that a perimedullary arteriovenous fistula (AVF) at the L2 level was detected fed by the anterior spinal artery which filled via the radiculomedullary artery from the right T9 intercostal artery. Large dilated veins drained mainly caudalward. Also intradural calcification was seen on CT at the L4 level. The fistula was embolized successfully. Control MR angiographies taken 4 and 8 months later had a lumbar intradural vessel which resembled the main draining vein of the spinal cord AVF, but was smaller. Spinal angiogram then showed that the spinal cord arteriovenous fistula was still occluded but at the L4 level there was a dural arteriovenous fistula fed by the left L4 lumbar artery, which was nor formerly examinated. The fistula drained cranialward via the same vein which had drained the spinal cord fistula caudalward but the vein was much smaller now. The fistula was at the same region as the calcification seen on CT.

Spinal cord arteriovenous fistulas involving the conus medullaris: presentation, management, and embryologic considerations

BACKGROUND Spinal cord arteriovenous fistulas (SCAVF) are uncommon congenital lesions that usually involve the most caudal aspects of the cord. We present three cases of SCAVF that illustrate the clinical manifestations and possible management options. The characteristic involvement of the conus medullaris and an associated tethered spinal cord in one of our patient suggests that a disorder of secondary neurulation may be involved in the formation of these arteriovenous shunt lesions. METHODS Review of records and radiologic studies in three consecutive patients with SCAVF’s treated at this institution. RESULTS All three patients had SCAVF involving the lower lumbar spinal cord segments or the conus. One of the conus lesions was associated with tethering of the spinal cord. One small lesion (Type A) was treated surgically, whereas the two larger lesions (Type B) were treated using interventional neuroradiologic techniques. CONCLUSIONS Both surgical and endovascular method have a role in management of these unusual spinal cord vascular malformations. The association with tethered cord suggests that the propensity for SCAVM to occur in the most caudal portions of the spinal cord may result from failure of secondary neurulation to properly develop the unique and complex vascular anatomy of the region.

Spinal Cord Arteriovenous Fistula Associated with a Giant Venous Pouch in a Three-Year-Old Child

An unusual case of direct spinal cord arteriovenous fistula (SCAVF) associated with a large venous pouch in a three-year-old child is presented. Features of this rare vascular lesion on MRI and selective angiography are described.

Spinal cord arteriovenous fistula: Usefulness of operative blood flow and pressure measurements during thoracotomy

Spinal cord arteriovenous fistula: Usefulness of operative blood flow and pressure measurements during thoracotomy