Filum terminale arteriovenous shunt with nidus structure: a report of rare condition and treatment consideration

BACKGROUND

 In the literature, filum terminale arteriovenous shunts (FTAVSs) always feature a single shunt point. Nidus-type FTAVSs have rarely been reported, and the best treatment strategy is unclear. This is a report of one exceptional case of a nidus-type FTAVS and surgical treatment of the lesion.

CASE DESCRIPTION

The patient suffered from cauda equina syndrome for 9 months. Magnetic resonance imaging and spinal angiography revealed a nidus-type FTAVF at the L2 level. Surgical resection was performed in the hybrid operating room, and the nidus was completely resected with the assistance of intraoperative methylene blue angiography and neurophysiological monitoring. The postoperative neurological function was stable.

CONCLUSIONS

A nidus-type arteriovenous shunt could originate from the FT, and in such cases, complete surgical resection with intraoperative neurophysiological monitoring in a hybrid operating room should be suggested.

Spinal Vascular Shunts: Single-Center Series and Review of the Literature of Their Classification

Spinal arteriovenous shunts (sAVSs) are an uncommon disease, constituting 3 to 4% of intradural lesions; 70% of these lesions are spinal arteriovenous fistulas (sAVFs), whereas spinal arteriovenous malformations (sAVMs) are rarer. Both share the problem of their classification due to the heterogeneity of their angioarchitecture. The aim of this study is to report a series of sAVSs treated in the neurosurgery department of the Hospital Nacional Guillermo Almenara during the 2018–2020 period and to present an overview of the current literature on sAVS classification. We reviewed all medical records of patients diagnosed with sAVFs and sAVMs during the 2018–2020 period, and then we analyzed images with Horos v4.0.0, illustrated some cases with Clip Studio Paint v1.10.5, and performed a descriptive statistical analysis with SPSS v25. Twelve patients were included in this study, eight of which were women (67%) and four of which were men (33%); the age range was from 3 to 74 years. Eight sAVSs were sAVFs, whereas four were sAVMs. The most frequent clinical manifestation was chronic myelopathy in seven patients (58%). Of those treated only by embolization, seven (70%) resulted in complete occlusion (five sAVFs and two sAVMs), while three (30%) remained with a residual lesion. At last follow-up, five patients (42%) improved clinically, and the seven remaining (58%) maintained the same neurological state. sAVSs require a detailed study of their angioarchitecture for proper management. The endovascular treatment is safe with acceptable cure rates. The surgical option should not be set aside.

Spinal arteriovenous fistula located in the filum terminale externa: A case report and review of the literature

A filum terminale arteriovenous fistula (FTAVF) is an extremely rare spinal arteriovenous fistula (AVF) and typically presents with myelopathy and conus medullaris syndrome caused by venous congestion in the spinal cord. Most reported FTAVFs are intradural pial AVFs with perimedullary drainage in the filum terminale interna. However, there are no reports of AVFs in the filum terminale externa (FTE). We describe a case involving a 68-year-old man with an AVF in the FTE who presented with progressive myelopathy and underwent successful endovascular treatment. We identified the specific shunt point by fusing postoperative computed tomography and magnetic resonance images. The features of the extradural sac AVF developed in the FTE may mimic those of a dural AVF with dural supply to the FTE covered by the dural component, unlike typical FTAVFs where the shunt develops at the pia mater. This case makes a significant contribution to the field by increasing the understanding of the clinical characteristics of an AVF that develops in the FTE and its angioarchitecture.

Rare association between spinal dural arteriovenous fistulas and dysraphisms: Report of two cases and review of the literature with a focus on pitfalls in diagnosis and treatment

Spinal vascular malformations are uncommon yet important spinal pathologies commonly classified in congenital and acquired lesions. Spinal lipomas consist of three subtypes: intramedullary lipomas, lipomyelo(meningo)celes and lipomas of the filum. Although the association of spinal arteriovenous malformations (AVM) with other congenital anomalies is well known, the coexistence of dural arteriovenous fistulas (AVF) and tethered spinal cord is exceptionally rare and only eight cases have been reported. We present two cases from our institution and speculate on the possible origin of such a rare but insidious association. We review the current literature with a focus on possible pitfalls in diagnosis and treatment.

Spinal Arteriovenous Shunts: Angioarchitecture and Historical Changes in Classification

The purposes of this study were to review historical changes in the classification of spinal arteriovenous (AV) shunts and to propose a practical classification system. The associated literature regarding the classification of spinal AV shunts was reviewed in the angiography era between 1967 and 2015. The classification systems of spinal AV shunts and a proposed classification system were presented with neuroradiological imaging and medical illustrations. There have been seven major classification systems based on the evolution of diagnostic methods as well as treatments for spinal AV shunts: the first description of spinal AV shunts diagnosed and classified using spinal angiography in 1971; the second classification based on a case report of intradural direct perimedullary arteriovenous fistulas (AVFs) treated by microsurgery in 1987; the third classification based on a case series of intradural perimedullary AVFs treated by endovascular interventions in 1993; the fourth and fifth classification systems based on a case series of spinal AVFs and arteriovenous malformations (AVMs) treated by microsurgery or endovascular interventions in 2002; the sixth classification based on a case series of cranio-spinal dural AV shunts in 2009; and the seventh classification based on a case series of extradural AVFs treated by microsurgery and endovascular interventions in 2011. Based on historical reports, the author proposed a classification system according to the sites (dural, intradural, and extradural) and types (AVF and AVM) of AV shunts. By learning the historical background, we may obtain a clearer understanding of the complex and confusing classification system of spinal AV shunts.

A case of filum terminale arterial venous fistula needed a long arterial access for trans-arterial shunt obliteration

A 78-year-old man was referred to our institution with a predominantly progressive numbness of both legs, and bladder dysfunction with urinary retention. He was diagnosed as the symptomatic arteriovenous fistula of the filum terminale (AVFFT). A trans-arterial embolization (TAE) of the arteriovenous shunt was planned for his symptomatic AVFFT. The long distance between the origin of the radiculo meningeal artery (Th8) and the site of the fistula (S1) resulted in the first TAE having a feeder occlusion. The length of accessible feeder in the first TAE was the longest (about 40 cm) as the past reports of the endovascular therapy. However, complete shunt occlusion was accomplished at a second session two weeks after the initial TAE because a more accessible feeder was developed by the initial feeder occlusion.

Surgical and Endovascular Treatment for Spinal Arteriovenous Malformations

Spinal arteriovenous malformation (AVM) is a broad term that constitutes diverse vascular pathologies. To date, various classification schemes for spinal AVM have been proposed in literature, which helped neurosurgeons understand the pathophysiology of the disease and determine an optimal treatment strategy. To discuss indications and results of surgical and endovascular interventions for spinal AVM, this article refers to the following classification proposed by Anson and Spetzler in 1992: type I, dural arteriovenous fistula (AVF); type II, glomus intramedullary AVM; type III, juvenile malformations; and type IV, perimedullary AVF. In general, complete obliteration of the fistula is a key for better outcome in type I dural and type IV perimedullary AVFs. On the other hand, in type II glomus and type III juvenile malformations, functional preservation, instead of pursuing angiographical cure, is the main goal of the treatment. In such cases, reduction of the shunt flow can alleviate clinical symptoms. Proper management of spinal AVM should start with neurological examination and understanding of angioarchitectures, which provide critical information that guides the indication and modality of intervention. Finally, close collaboration of the microsurgical and endovascular teams are mandatory for successful treatment.

Complex spinal arteriovenous fistula of the craniocervical junction with pial and dural shunts combined with contralateral dural arteriovenous fistula

A high cervical dural arteriovenous fistula (dAVF) is relatively rare and tends to have different features, as compared with a thoracolumbar dAVF. Here, we report a case involving a complex AVF located at the craniocervical junction that was fed by the dural and pial arteries, combined with a contralateral dAVF.

Foix-alajouanine syndrome presenting as acute cauda equina syndrome: a case report

Study Design Case report. Objective Present a case of Foix-Alajouanine syndrome that presented as acute cauda equina syndrome and discuss the pathophysiology and management. Methods An adult male patient developed sudden onset of back pain and leg pain with weakness of the lower limbs and bladder/bowel dysfunction typical of cauda equina syndrome. Emergency magnetic resonance imaging revealed no compressive lesion in the spine but showed tortuous flow voids and end-on blood vessels in the peridural region suggesting spinal arteriovenous malformation resulting in Foix-Alajouanine syndrome. Results The case was managed by endovascular embolization with excellent results. The pathophysiology, imaging features, management, and literature review of the syndrome is discussed. Conclusion The authors conclude that this condition may be an important differential diagnosis for cauda equina syndrome.

Surgical management of combined intramedullary arteriovenous malformation and perimedullary arteriovenous fistula within the hybrid operating room after five years of performing focus fractionated radiotherapy: case report

Perimedullary arteriovenous fistula (AVF) shunts occur on the spinal cord surface and can be treated surgically or by endovascular embolization. In contrast, the nidus of an intramedullary arteriovenous malformation (AVM) is located in the spinal cord and is difficult to treat surgically or by endovascular techniques. The benefits of radiotherapy for treating intramedullary AVM have been published, but are anecdotal and consist largely of case reports. We present a case of combined cervical intramedullary AVM and perimedullary AVF which received surgical treatment within a hybrid operating room (OR) after 5 years of focus fractionated radiotherapy. A 37-year-old male presented with stepwise worsening myelopathy. Magnetic resonance imaging and spinal angiography revealed intramedullary AVM and perimedullary AVF at the C3 to C5 levels. In order to reduce nidus size and blood flow, we first performed focal fractionated radiotherapy. Five years later, the lesion volume was reduced. Following this, direct surgery was performed by an anterior approach using corpectomy in the hybrid OR. The spinal cord was monitored by motor-evoked potential throughout the surgery. Complete obliteration of the fistulous connection was confirmed by intraoperative indocyanine green video-angiography and intraoperative angiography, preserving the anterior spinal artery. We conclude that surgical treatment following focal fractionated radiotherapy may become one strategy for patients who are initially deemed ineligible for endovascular embolization and surgical treatment. Furthermore, the hybrid OR enables safe and precise treatment for spinal vascular disorders in the fields of endovascular treatment and neurosurgery.