Ascending and Descending Thoracic Vertebral Arteries

Thoracic vertebral arteries are anastomotic chains similar to cervical vertebral arteries but found at the thoracic level. Descending thoracic vertebral arteries originate from the pretransverse segment of the cervical vertebral artery and curve caudally to pass into the last transverse foramen or the first costotransverse space. Ascending thoracic vertebral arteries originate from the aorta, pass through at least 1 costotransverse space, and continue cranially as the cervical vertebral artery. This report describes the angiographic anatomy and clinical significance of 9 cases of descending and 2 cases of ascending thoracic vertebral arteries. Being located within the upper costotransverse spaces, ascending and descending thoracic vertebral arteries can have important implications during spine interventional or surgical procedures. Because they frequently provide radiculomedullary or bronchial branches, they can also be involved in spinal cord ischemia, supply vascular malformations, or be an elusive source of hemoptysis.

Republished: Bilateral and symmetric isolated dorsospinal arteries with prominent anterior radiculomedullary contribution

We present the case of a 15-year-old girl with a left T7 spinal epidural arteriovenous fistula (SEAVF), in whom bilateral and symmetric isolated T9 dorsospinal arteries (DAs) were incidentally documented, each providing a significant contribution to the anterior spinal artery. Recognizing the existence of isolated DAs of direct aortic origin is critical, both for the diagnostic evaluation and for the management of spinal vascular diseases. Notably, isolated DAs tend to branch off significant radiculomedullary arteries, which vascularize the normal spinal cord but have also been shown to supply spinal vascular malformations.

Early description of synchronous double spinal vascular malformations by Łucja Frey in 1928

The Polish neurologist Łucja Frey (1889–1942) is principally remembered for her description of the auriculotemporal nerve (or Frey's) syndrome. She also reported a complex case of spinal cord vascular malformation in 1928, which included one of the earliest accurate anatomopathological depictions of a spinal arteriovenous malformation as well as the first known observation of double synchronous spinal cord vascular malformation.

An abbreviated translation of Frey's report is followed by a discussion of the place occupied by her contribution in the development of our current understanding of spinovascular disorders.

Intraoperative spinal digital subtraction angiography: indications, technique, safety, and clinical impact

Background

Cerebral intraoperative DSA (IODSA) is a well-described, routinely performed procedure that allows the effectiveness of cerebrovascular interventions to be evaluated in the operating room. Spinal IODSA, on the other hand, is infrequently obtained and has received less attention.

Objective

To discuss the indications, technique, safety, and clinical impact of spinal IODSA.

Materials and methods

Twenty-three patients underwent 45 thoracic and/or lumbar spinal IODSA between 2005 and 2016, either immediately before surgery for lesion localization or after the intervention to evaluate its effectiveness. Indications included 21 vascular malformations and 2 diaphragmatic crus compression syndromes. A long femoral arterial sheath with its hub positioned on the lateral surface of the thigh was used to allow catheter manipulations in the prone position.

Results

All targeted intersegmental arteries (ISAs) were successfully catheterized. The course of surgery was changed in 6 instances (26.1%). In 4 cases of epidural or perimedullary arteriovenous fistulae (AVFs), a residual lesion required additional intervention. In one case of epidural AVF, initial IODSA revealed spontaneous resolution of the lesion, preventing unnecessary surgery. Finally, angiography performed in a case of diaphragmatic crus syndrome showed thrombosis of the ISA and non-visualization of the artery of Adamkiewicz. Recanalization was obtained by IA thrombolysis, with excellent clinical outcome. No intraprocedural or postprocedural complication was noted.

Conclusions

Spinal IODSA is a safe technique that offers an immediate assessment of the effectiveness of a spinovascular surgical procedure, notably epidural and perimedullary AVFs. Spinal IODSA was technically successful in all cases, influencing the surgical strategy in 6 of 23 patients, including one patient who benefited from intraoperative endovascular therapy.

Bilateral and symmetric isolated dorsospinal arteries with prominent anterior radiculomedullary contribution

We present the case of a 15-year-old girl with a left T7 spinal epidural arteriovenous fistula (SEAVF), in whom bilateral and symmetric isolated T9 dorsospinal arteries (DAs) were incidentally documented, each providing a significant contribution to the anterior spinal artery. Recognizing the existence of isolated DAs of direct aortic origin is critical, both for the diagnostic evaluation and for the management of spinal vascular diseases. Notably, isolated DAs tend to branch off significant radiculomedullary arteries, which vascularize the normal spinal cord but have also been shown to supply spinal vascular malformations.

Direct origin of the right colic artery from the abdominal aorta

An isolated right colic artery originating directly from the abdominal aorta was incidentally observed during diagnostic spinal angiography. Variations in origin of the right colic artery are reviewed, and their embryology and potential clinical implications discussed.

Normal Venous Phase Documented during Angiography in Patients with Spinal Vascular Malformations: Incidence and Clinical Implications

BACKGROUND AND PURPOSE

A key angiographic sign observed in patients with spinal vascular malformations is the absence of a normal venous phase. While this finding alone is often believed to rule out a lesion impacting the perimedullary venous drainage, the observation of a venous phase in several patients with vascular malformations led us to reconsider the validity of that sign.

MATERIALS AND METHODS

Eighty-one patients with 6 spinal arteriovenous malformations, 16 perimedullary arteriovenous fistulas, 61 spinal epidural or dural AVFs, and 1 paravertebral AVF (2 patients had multiple lesions) were reviewed. The venous phase was defined as normal, absent, or indeterminate. The venous phase timing was analyzed in patients with spinal dural or epidural AVFs.

RESULTS

The existence of a venous phase could not be determined for technical reasons in 23 patients. A venous phase was documented in 25 of 58 patients (43%), including 16 of 49 vascular malformations (40.0%) with perimedullary venous drainage. Twelve of the 30 patients (40.0%) with dural or epidural AVFs had a normal venous phase, appearing, on average, 10.1 seconds and best visualized 15.0 seconds after opacification of the artery of Adamkiewicz.

CONCLUSIONS

A normal venous phase was observed in 43% of patients with spinal vascular malformations, and within an acceptable delay (<18 seconds) in 40% of slow-flow AVFs. While it remains an important angiographic sign, the observation of a normal venous phase cannot be used to exclude the presence of a vascular malformation or justify interrupting a diagnostic spinal angiogram.

Ventral and Dorsal Persistent Primitive Ophthalmic Arteries

BACKGROUND

Before the development of the adult ophthalmic artery (OA), the primitive maxillary artery (MA), the primitive dorsal OA, and the primitive ventral OA contribute to the vascularization of early ocular structures, whereas the primitive olfactory artery (OlfA) forms in the vicinity of the optic vesicle. These vessels are involved in several OA origin variants.

OBJECTIVE

To clarify the developmental history of the OA, emphasizing in particular the criteria used to define persistent primitive OAs.

METHODS

Eight rare variants relevant to the discussion of aberrant OA origins are presented.

RESULTS

Five abnormal anatomic configurations are described including (1) OAs branching from the cavernous internal carotid artery (ICA) involving a persistent primitive MA, (2) OAs originating from the distal supraclinoid ICA involving persistent primitive ventral or dorsal OAs, (3) an OA originating from the anterior cerebral artery (ACA) involving a persistent primitive OlfA, (4) a persistent primitive OlfA, and (5) infraoptic ACAs involving the persistent primitive MA, OlfA, and OA.

CONCLUSION

Discrepancies regarding the identification of persistent primitive OAs appear to result from a misinterpretation of the literature. Notably, an OA arising from the cavernous segment of the ICA derives from a primitive MA, whereas an OA arising from the ACA represents the partial persistence of a primitive OlfA; neither corresponds to a persistent primitive OA. Two new observations of this latter variant, which is exceptional, are presented.

Diagnostic Inefficiency of Nonselective Spinal Angiography (Flush Aortography) in the Evaluation of the Normal and Pathological Spinal Vasculature

Selective spinal angiography was introduced in the 1960s to palliate the poor sensitivity of nonselective techniques for the evaluation of the spinal cord vasculature. Recent advances made in the field of angiography seem to have prompted a renewed interest for nonselective spinal angiography, or flush aortograms. This pictorial essay, illustrated with 2 cases of presurgical evaluation of the spinal cord supply and 2 cases of spinal vascular malformation, suggests that nonselective techniques remain insufficient to properly document the normal or pathological spinal vasculature. While flush aortography can play a role as a complement to spinal angiography, for example, to locate vessels eluding selective catheterization, relying on nonselective studies to rule out the presence of a spinal vascular malformation or to identify the normal spinal cord supply before surgical interventions may lead to false-negative investigations with potentially devastating consequences.

Diploic arteriovenous fistulas--classification and endovascular management

BACKGROUND

The authors report on two cases of diploic arteriovenous fistulas (AVFs) in the left parieto-occipital region of a 20-year-old female and the right parietal region of a 68-year-old male. The clinical presentation, angiographic appearance, and endovascular management of these rare lesions are discussed.

METHODS

Retrospective data from two patients with diplopic AVFs are examined with a review of all published cases of diploic arteriovenous fistulas.

RESULTS

Where previously reported diploic AVFs showed venous drainage to be intracranial or combined, two case studies examined by the authors found exclusively extracranial drainage in the AVFs. In both case studies the lesions were primarily fed by the middle meningeal artery and treated via a transarterial endovascular approach using n-BCA glue.

CONCLUSIONS

After reviewing all reported cases of AVF in the literature and combining our two new observations, we concluded that diploic AVFs can have three types of venous outflow: draining toward dural sinuses only, toward extracranial veins only, and combining the dural and extracranial pathways.

Transmedullary Venous Anastomoses: Anatomy and Angiographic Visualization Using Flat Panel Catheter Angiotomography

Flat panel catheter angiotomography, a recently developed angiographic technique, offers a spinal equivalent to the venous phase obtained during cerebral angiography. This report of 8 clinical cases discusses the flat panel catheter angiotomography appearance of a type of spinal venous structure until now principally known through the analysis of postmortem material, transmedullary venous anastomosis. The illustrated configurations include centrodorsolateral, median anteroposterior, median anteroposterior with duplicated origin, and combined centrodorsolateral/median anteroposterior transmedullary venous anastomoses, while a pathologic example documents the potential role of transmedullary venous anastomoses as collateral venous pathways. Two of the reported configurations have not been previously documented. Transmedullary venous anastomoses are normal venous structures that need to be differentiated from spinal cord anomalies, such as intramedullary vascular malformations.

Abstract W P71: Analysis of Large Volume Penumbra PC400 Coil and 025” ID Microcatheter in Treatment of Anterior Communicating Artery Aneurysm Embolization: Safety and Efficacy Outcomes from a Multicenter Experience

Purpose: We report clinical experience and long-term results in treating 39 AcomA aneurysms in 39 patients using the Penumbra PC400 large volume coil at 13 high volume centers. With its .020” coil size and use of 025” ID microcatheter, the safety and efficacy of the Penumbra Coil 400 (PC400) System in embolization of AcomA aneurysms has not yet been characterized.

Methods: Our treatment cohort consisted of 39 aneurysms ranging between 3.5mm and 17mm, treated between March 2012 and May 2014. Six-month follow up were assessed. Data on angiographic results and procedural complications were collected prospectively and analyzed.

Results: The mean aneurysm size was 6.2 mm, with 40.8% mean packing density. All aneurysms were treated entirely with PC400 coils, with mean of 5.1 coils placed. Twenty were ruptured and 19 unruptured. Sixty-six percent of the cases achieved an initial Raymond Scale of 1, and 23.7% achieved a Raymond scale of 2. The overall rate of retreatment was 0%, while the rate of morbidity and mortality caused by stroke <30 days was 1.8%. Comparison with a recently published meta-analysis showed similar or superior outcomes with lower procedural complication rates, most notably lower overall vasospasm rate of 6% vs 17% (p=0.023), lower retreatment rate of 0% vs 9% and higher long-term complete and near-complete occlusion of 96% vs 83% with PC400 coils (Tables 1, 2).

Conclusion: ACE study data demonstrate that embolization using the PC400 System and 025” ID microcatheter in AcomA aneurysms leads to safe and effective short- and long-term outcomes.

Collaterals: an important determinant of prolonged ischemic penumbra versus rapid cerebral infarction?

Intravenous tissue plasminogen activator is the mainstay for the treatment of acute ischemic stroke in patients presenting within 4.5 h of symptom onset. Studies have demonstrated that treating patients early leads to improved long-term outcomes. MR imaging currently allows quantification of the ischemic penumbra in order to better identify individuals most likely to benefit from intervention, irrespective of “time last seen normal.” Its increasing use in clinical practice has demonstrated individual differences in rate of infarction. One explanation for this variability is a difference in collateral blood flow. We report two cases that highlight the individual variability of infarction rate, and discuss potential underlying mechanisms that may influence treatment decisions and outcomes.

Periconal arterial anastomotic circle and posterior lumbosacral watershed zone of the spinal cord

BACKGROUND

The existence of spinal cord watershed territories was suggested in the 1950s. Segmental infarcts within the junctional territories of adjacent radiculomedullary contributors and isolated spinal gray matter ischemia constitute two well-recognized types of watershed injury. This report describes the existence of another watershed territory related to the particular configuration of the spinal vasculature in the region of the conus medullaris.

METHODS

The anatomical bases underlying the concept of a posterior lumbosacral watershed zone are demonstrated with angiographic images obtained in a 16-year-old child. The clinical importance of this watershed zone is illustrated with MRI and angiographic data of three patients with a conus medullaris infarction.

RESULTS

In all three cases of spinal ischemia an intersegmental artery providing a significant radiculomedullary contribution for the lower cord was compromised by a compressive mechanism responsible for decreased spinal cord perfusion (diaphragmatic crus syndrome in two cases, disk herniation in one). The ischemic injury, located at the junction of the anterior and posterior spinal artery territories along the dorsal aspect of the conus medullaris, was consistent with a watershed mechanism. This zone is at risk because of the caudocranial direction of flow within the most caudal segment of the posterior spinal arterial network which, from a functional standpoint, depends on the anterior spinal artery.

CONCLUSIONS

The posterior thoracolumbar watershed zone of the spinal cord represents an area at increased risk of ischemic injury, particularly in the context of partial flow impairment related to arterial compression mechanisms.