Intraorbital Arteriovenous Fistulas: Case Series and Systematic Review

Operative Neurosurgery 27:23–30, 2024

Intraorbital arteriovenous fistulas (AVFs) are an extremely rare subtype of intracranial fistula with ophthalmic symptoms similar to cavernous sinus dural AVFs or carotid cavernous fistulas but worse visual outcomes. Here, we present a case series and thorough systematic review on intraorbital AVFs to demonstrate treatment modalities and address this rare type of AVF.

METHODS: We conducted a retrospective study at a single center, in which we identified all cases of intraorbital AVFs that occurred between 2002 and 2022. We collected and analyzed data on demographics, fistula characteristics, treatment methods, clinical outcomes, and fistula closure. In addition, we conducted a systematic review of intraorbital AVFs.

RESULTS: Seven cases in our center and 41 cases of intraorbital AVFs reported in the 35 articles were identified. At our center, transarterial embolization (TAE) (42.9%) alone resulted in immediate complete occlusion in 3 cases. Transvenous embolization (14.3%) resulted in one case of immediate complete occlusion. In 2 cases, surgery (28.6%) resulted in immediate complete occlusion. In one case, conservative treatment (14.3%) was used, and the fistula was eventually spontaneously occluded. Immediate complete occlusion rate was 85.7%. One blindness occurred (14.3%). In the literature reported, 3 cases (60%) of retinal artery occlusion were reported when performing TAE via the ophthalmic artery. Two fistulas recurred as reported. In 33 (80.5%) patients, the fistula was finally completely occluded.

CONCLUSION: TAE via the ophthalmic artery carries a high risk of blindness and a low cure rate. Transvenous techniques such as conventional transvenous routes, surgical exposure, or direct puncture of the drainage vein have been used as the first line of treatment for intraorbital AVFs.

Semi-quantitative assessment of flow dynamics during indocyanine green video-angiography in the treatment of intracranial dural arteriovenous fistulas

Semi-quantitative assessment of flow dynamics during indocyanine green video-angiography in the treatment of intracranial dural arteriovenous fistulas

Acta Neurochir (2016) 158:1387–1391

Indocyanine green video-angiography (IG-VA) is applied for intraoperative localisation and verification of surgical disconnection of intracranial dural arteriovenous fistulas (iDAVFs).

Method We describe the technique of semiquantitative flow analysis using Flow800 software that implements conventional IG-VA. Our method relies on simple comparison of the fluorescence curves of the exposed vessels, allowing precise localisation of the DAVF draining vein and verification of its surgical disconnection.

Conclusions Semi-quantitative flow analysis with Flow800 software during IG-VA is a reproducible technique that may overcome the limitations of conventional IG-VA in the surgical treatment of DAVFs.

Microsurgical resection of an intramedullary glomus arteriovenous malformation in the high cervical spinal cord

Microsurgical resection of an intramedullary glomus arteriovenous malformation in the high cervical spinal cord

Acta Neurochir (2015) 157:1659–1664

Spinal intramedullary arteriovenous malformations (AVMs) fed by an anterior spinal artery are surgically challenging vascular lesions.

Method 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.

Conclusion Patients who underwent these techniques achieved good outcomes with minimal bleeding and morbidity.

Spinal extradural arteriovenous fistulas

Spinal extradural arteriovenous fistulas

J Neurosurg Spine 19:582–590, 2013

Our understanding of spinal extradural arteriovenous fistulas (eAVFs) is relatively limited. In this study the authors aimed to provide the demographics, natural history, and treatment results of these rare lesions.

Methods. The authors performed a pooled analysis of data in the PubMed database through December 2012. Individualized patient data were extracted to elucidate demographic, clinical, and angioarchitectural features of spinal eAVFs as well as outcomes following different treatment strategies.

Results. Information on 101 patients was extracted from 63 eligible studies. The mean patient age was 45.9 years, and there was no significant overall sex predilection. Only 3% of the lesions were incidental, whereas 10% occurred in patients who had presented with hemorrhage. None of the 64 patients with at least 1 month of untreated follow-up sustained a hemorrhage over a total of 83.8 patient-years. Patients with lumbosacral eAVFs were significantly older (mean age 58.7 years, p < 0.0001), were significantly more often male (70% male, p = 0.02), had significantly worse presenting Aminoff-Logue motor and bladder scores (p = 0.0008 and < 0.0001, respectively), and had the greatest prevalence of lesions with intradural venous drainage (62% of cases, p < 0.0001). Neurofibromatosis Type 1 (30% of cases, p < 0.0001) and subarachnoid hemorrhage (9% of cases, p = 0.06) were associated with and exclusively found in patients with cervical eAVFs. The overall complete obliteration rate was 91%. After a mean follow-up of 1.7 years, the clinical condition was improved in 89% of patients, the same in 9%, and worse in 2%. Obliteration rates and outcome at follow-up did not significantly differ between surgical and endovascular treatment modalities.

Conclusions. Spinal eAVFs are rare lesions with a low risk of hemorrhage; they cause neurological morbidity as a result of mass effect and/or venous hypertension. Their treatment is associated with a high rate of complete obliteration and improvement in preoperative symptoms.

Emergency Noninvasive Angiography for Acute Intracerebral Hemorrhage

CTA

Am J Neuroradiol 34:1481– 87. 2013

Spontaneous ICH is a devastating condition and is associated with significant mortality in the acute phase due to ongoing hemorrhage and hematoma expansion. A growing body of evidence suggests that there may be considerable utility in performing noninvasive vascular imaging during the acute-to-early phase of ICH.

CTA has become widely available and is sensitive and specific for detecting vascular causes of secondary ICH such as aneurysms, arteriovenous malformations, dural arteriovenous fistulas, intracranial dissections, and neoplasm.

CT venography can also diagnose dural sinus thrombosis presenting as hemorrhagic infarction.

Recent data from stroke populations demonstrate a relatively low risk to patients when contrast is administered in the absence of a known serum creatinine. Detection of acute contrast extravasation within the hematoma (“spot sign”) with CT angiography is predictive of subsequent hematoma expansion and is associated with increased morbidity and mortality.

Risk stratification based on acute CTA can inform and expedite decision-making regarding intensive care unit admission, blood pressure control, correction of coagulopathy, and neurosurgical consultation. Noninvasive vascular imaging should be considered as an important component of the initial diagnostic work-up for patients presenting with acute ICH.

Spinal Pial (Type IV) Arteriovenous Fistulae

Spinal Pial (Type IV) Arteriovenous Fistulae

Neurosurgery 73:141–151, 2013

Demographics, hemorrhage risk, and results of surgical and endovascular treatment of spinal pial (type IV) arteriovenous fistulae (AVFs) across a large patient group have not been previously reported.

OBJECTIVE: To report demographics, hemorrhage rates, and treatment results for these AVFs.

METHODS: We performed a pooled analysis via the PubMed and Embase databases through November 2012. Individualized patient data were extracted and analyzed using Cox proportional hazards regression to obtain hazard ratios for hemorrhage risk factors and pooled for baseline demographics and treatment results.

RESULTS: We extracted information on 213 patients from 28 studies. Only 1% of lesions were incidental; 93% of patients presented with neurologic deficits and 36% with hemorrhage. Patients with type IVa lesions were significantly older (mean age, 46.9 years) and demonstrated a male sex predilection (68% male). Patients with type IVc lesions were significantly younger (mean age, 18.7 years), had no sex predilection, and had the highest prevalence of syndromic conditions (29% of cases). The annual hemorrhage rate was 2.5% (95% confidence interval [CI]: 1.4%-4.7%), increasing to 5.6% for hemorrhagic fistulae (95% CI: 3.0%-10.7%; hazard ratio: 6.31; 95% CI: 0.69-57.4; P = .10). Patient sex, fistula location, and fistula subclass were not significant risk factors for hemorrhage. The surgical obliteration rate was 88%; 68% of patients improved, 26% were the same, and 6% were worse. The endovascular obliteration rate was 74%; 75% of patients improved, 14% were the same, and 11% were worse.

CONCLUSION: We demonstrate the utility of the Anson-Spetzler a-c subclassification and underscore the efficacy of surgical and endovascular spinal AVF treatment.

Characteristics and long-term outcome of 251 patients with dural arteriovenous fistulas in a defined population

DAVF-headache

J Neurosurg 118:923–934, 2013

Management of dural arteriovenous fistulas (DAVFs) has changed during the last decades due to increased knowledge of their pathophysiology and natural history as well as advances in treatment modalities. The authors describe the characteristics and long-term outcome of a large consecutive series of patients with DAVFs.

Methods. Altogether 251 patients with 261 DAVFs were treated in 2 of the 5 neurosurgery departments at Helsinki and Kuopio University Hospitals between 1944 and 2006. Clinical data and radiological examinations were reviewed to assess patients’ overall long-term clinical outcome.

Results. The detection rate of DAVFs increased markedly in the 1970s and again in the 1990s when digital subtraction angiography was introduced. The incidence of DAVFs in a defined southern Finnish population was 0.51 per 100,000 individuals per year, which represents 32% of all the brain arteriovenous malformations. In the early part of the series, DAVFs were treated by proximal ligation of the feeding arteries. Later, most of the patients underwent preoperative embolization and subsequent craniotomy, and since 2000 stereotactic radiosurgery has been increasingly used in the treatment of DAVFs. Fifty-nine percent of the 261 fistulas were totally occluded. Treatment-related major complications were seen in 21 patients.

Conclusions. The advances in diagnostic methods (digital subtraction angiography, CT, and MRI) increased the detection rate of DAVFs, and as treatment modalities developed, the results of treatment and outcome of patients markedly improved with the introduction of endovascular techniques and stereotactic radiosurgery. Microsurgery is of limited use in DAVFs resistant to other treatment modalities.

Safety and Efficacy of Intraoperative Angiography in Craniotomies for Cerebral Aneurysms and Arteriovenous Malformations

Intraoperative angiography in aneurysms surgery

Neurosurgery 71:1162–1169, 2012

In an era of indocyanine angiography, the routine use of intraoperative angiography (IOA) in the surgical treatment of aneurysms and vascular malformations is controversial.

OBJECTIVE: To retrospectively assess the safety and efficacy of IOA and to determine predictors of surgical revision.

METHODS: Between 2003 and 2011, IOA was performed during surgical treatment of 976 aneurysms, 101 arteriovenous malformations (AVMs), and 16 arteriovenous fistulas.

RESULTS: In 80 of 976 aneurysms (8.2%), IOA prompted clip repositioning. The reason for readjustment was residual aneurysm in 54.7%, parent vessel occlusion in 42.9%, and both in 2.4% of cases. In multivariate analysis, increasing aneurysm size (P,.001), ruptured aneurysm (P,.001), and increasing number of vessels injected (P,.001) were strong predictors of clip readjustment. There was a strong trend for posterior circulation aneurysm location to predict clip repositioning (P = .06). IOA revealed residual nidus/ fistula requiring further intervention in 9 of 101 AVMs (8.9%) and 3 of 16 arteriovenous fistulas (18.8%). Of 9 AVMs requiring a surgical revision, 2 (22.2%) were Spetzler-Martin grade II, 5 (55.6%) were grade III, and 2 (22.2%) were grade IV. Mean Spetzler-Martin grade was 3.0 in AVMs requiring surgical revision compared with 2.3 in those not requiring revision (P = .05). IOA-related complications were all transient or minor and occurred in 0.99% of patients; none resulted in permanent morbidity.

CONCLUSION: IOA remains a valuable tool in the surgical treatment of brain vascular abnormalities, guiding surgical re-exploration in >8% of cases. Easy access to an angiographer and routine use of IOA are important factors contributing to procedural safety and efficacy.

Endovascular Treatment of Cervical Giant Perimedullary Arteriovenous Fistulas

Neurosurgery 70:141–149, 2012 DOI: 10.1227/NEU.0b013e31822ec19e

Giant perimedullary arteriovenous fistulas (GPMAVFs) located in the cervical region are a rare pathology with distinctive characteristics.

OBJECTIVE: To evaluate clinical presentation and different endovascular treatment options of cervical GPMAVFs and review previously published data in the literature regarding cervical GPMAVFs.

METHODS: Six patients with cervical GPMAVFs were found in the spinal vascular malformations database of our group collected between 1990 and 2009. Endovascular techniques and treatment outcomes were evaluated and compared with other published series.

RESULTS: Clinical presentations were progressive motor deficit (5 patients), hematomyelia (1 patient), meningeal syndrome (1 patient), and respiratory arrest and gait apraxia (1 patient). Three patients were treated by the transarterial approach. One patient was treated by the transvenous approach due to previous embolizations resulting in a proximal occlusion and preventing a safe transarterial approach. A transvenous approach was used in another patient due to complex arterial anatomy. In 1 patient, direct percutaneous puncture of the venous pouch was necessary because of previous proximal occlusion of the arteries. All embolizations resulted in complete occlusions with clinical improvement, and there was no recanalization during a mean follow-up of 21 months.

CONCLUSION: Transarterial embolization of cervical GPMAVFs is safe and effective when it is done in highly experienced centers. Cervical GPMAVFs that cannot be accessed by the transarterial technique due to their complex angioarchitecture can be treated by transvenous embolization or direct puncture of the venous pouch.