Embolization of a dural arteriovenous fistula of the ventral cervical spinal canal in a nine-year-old boy

Delayed Postoperative Neurologic Deficits in Spinal Deformity Surgery

STUDY DESIGN

A cross-sectional survey of surgeon members of the Scoliosis Research Society (SRS).

OBJECTIVE

This study sought to characterize the incidence, clinical presentation, diagnostic workup, treatment, and neurologic prognosis following delayed postoperative neurologic deficit (DPND) in patients undergoing spinal deformity surgery.

SUMMARY OF BACKGROUND DATA

DPND is a potentially devastating condition following spinal surgery, characterized by the development of a neurological deficit within hours or days of the surgical procedure. To date, only case reports and small case series have been published on the topic.

METHODS

We developed a survey to characterize DPND following spinal deformity surgery. This survey was distributed to surgeon members of the SRS through email and standard mail. The overall response rate was 38% (352/929).

RESULTS

Our results suggest an estimated DPND incidence of 1 of 9910 cases (0.01%). Eighty-one surgeons (23%) experienced at least 1 DPND in the past 10 years (92 total cases). Most common diagnoses were scoliosis (69%), kyphosis (23%), and spondylolisthesis (14%); 20% were revision surgeries. The number of hours to deficit onset was as follows: 1 to 12 (36%), 13 to 24 (27%), 25 to 48 (27%), more than 48 (10%). The most commonly cited sources of injury included ischemic injury (38%) and cord compression (15%). Forty-one percent experienced complete neurologic recovery, 26% partial, and 33% no recovery. Twenty-one percent of patients achieved final neurologic status within 1 week, 38% by 1 month, and 73% by 6 months. Patients with compression-related DPND had a significantly greater likelihood of experiencing some neurologic recovery (≥1 ASIA Grade) than ischemia-related DPND (86% versus 51%, P = 0.049).

CONCLUSIONS

DPND occurs at an estimated incidence of 0.01%. Sixty-three percent of DPND cases occurred within the first 24 hours and 90% within 48 hours. Complete (41%) or partial (26%) neurologic recovery may be expected, especially in compression-related DPND, emphasizing the need for perioperative vigilance, prompt recognition, and early intervention.

LEVEL OF EVIDENCE

4.

[Spinal dural arteriovenous fistula with peri-medullary venous drainage: analysis of a series from a single centre and review of the literature]

INTRODUCTION

The optimal diagnosis and therapeutic managements of spinal dural arteriovenous fistulae, a rare disease, is discussed.

MATERIAL AND METHODS

We report a series of 10 patients seen in a 7-year period, treated by embolization.

RESULTS

There were 6 males and 4 females, with an average age of 58.4 years (range: 31 to 74 years). Diagnosis was made 2 days to 5 years (mean 15.3 months) after symptom onset with a high rate of incomplete or atypical clinical patterns (prolonged isolated sensory disorder, lumbo-sciatalgia, claudication, monoplegia), or sudden-onset deficit. In all cases, spinal MRI showed an intramedullary high-intensity signal on T2-weighted images but enlarged intradural vessels in only 70p.cent of cases. Angiography showed in all cases an arteriovenous fistula at the upper dorsal level (T1 to T7, 5 cases), lower dorsal (T8-T12, in 3 cases) and lumbar levels (2 cases). The fistula was successfully obliterated after initial embolization in 3 cases, but two (2 cases) or 3 procedures (2 cases) were sometimes required. The endovascular therapy failed in 3 cases.

CONCLUSION

In this series, the fistula was successfully obliterated in 70p.cent of patients. In the literature, fistula of 96.8p.cent to 97.9p.cent of patients were obliterated by surgery, which is a more invasive treatment. Embolization could be used as the first-line therapy, but incomplete obliteration requires rapid surgery. While the success of embolization is demonstrated, MRI and angiography must still be performed 6 months later.

Dural arteriovenous fistula of the lumbar spine presenting with subarachnoid hemorrhage. Case report and review of the literature

The authors report on a patient presenting with subarachnoid hemorrhage (SAH) that was initially attributed to an aneurysm of the right internal carotid artery. During surgical exploration and placement of a clip, however, it was observed that the aneurysm had not ruptured. Diagnostic workup including spinal magnetic resonance imaging revealed a vascular malformation of the lumbar spinal canal within a subarachnoid hematoma. Spinal angiography demonstrated a spinal dural arteriovenous fistula (DAVF) (Type I spinal arteriovenous malformation) with a feeding vessel arising from the L-4 radicular artery. In the literature, SAH due to spinal DAVFs is rare; only cases of dural fistulas of the craniocervical junction and the cervical spine have been reported. This is the first case of SAH that can be attributed to a lumbar DAVF. Although unusual even in cases of cervical DAVF, SAH as a presenting symptom may occur in spinal DAVF of any location. Nontraumatic SAH should not be prematurely attributed to the rupture of an intracranial aneurysm if the clinical findings and imaging results are inconclusive.

Spinal dural arteriovenous fistula and venous aneurysm: an unusual association

OBJECTIVE

Although spinal intradural arteriovenous malformations have frequently been associated with venous aneurysms, spinal dural arteriovenous fistulas typically are not. We describe a case of conus medullaris compression by a large saccular venous aneurysm of a spinal dural arteriovenous fistula. As these lesions are slow-flow arteriovenous shunts, development of a venous aneurysm is an unexpected condition. Pathogenesis of these aneurysms is briefly discussed.

METHODS

A 61-year-old man presented with progressive spastic paraparesis of 1-year duration. Spinal magnetic resonance (MR) suggested abnormal serpiginous vessels and a partially thrombosed aneurysm at the level of conus medullaris. Spinal angiography was performed but some lower thoracal and upper lumbar segments could not be catheterized because of severe atherosclerosis. As a result, vascular anomaly could not be demonstrated angiographically, but surgical exploration was found to be necessary because of positive clinical and MR findings.

RESULTS

An arteriovenous fistula that entered the spinal canal beneath the L1 pedicle on the left was identified. It was easily coagulated and cut. The partially thrombosed aneurysm within the conus medullaris was also resected.

CONCLUSIONS

Our case illustrates two important points related to patients harboring spinal dural arteriovenous fistulas (AVF): First, clinical suspicion and MR findings are important in diagnosis of these lesions and surgical exploration is indicated despite negative or nondiagnostic angiographic results in such cases. Second, venous aneurysms may be associated with spinal dural AVFs, and although spinal dural AVFs are low-flow lesions, the development of the venous aneurysm is probably a result of high venous pressure.

Venous manifestations of spinal arteriovenous fistulas

Spinal dural AVFs, the most common type of spinal arteriovenous malformations, are symptomatic because of venous hypertension and congestion. This has been referred to as venous congestive myelopathy. The typical MRI findings that reflect venous congestive myelopathy include peripheral T2 hypointensity that outlines a T2 hyperintensity within a swollen spinal cord. Enlarged perimedullary vessels are typically present. Contrast-enhanced MRA has become instrumental in localizing the site of these fistulas. Spinal epidural AVFs and the perimedullary spinal cord AVFs may also present with a congestive myelopathy and have similar findings on MRI. Angiography remains the gold standard for characterization of the angioarchitecture of spinal vascular malformations. [figure: see text] Multidisciplinary treatment planning is mandatory and requires knowledge of the natural history of these vascular lesions.

Modified classification of spinal cord vascular lesions

The literature on spinal vascular malformations contains a great deal of confusing terminology. Some of the nomenclature is inconsistent with the lesions described. Based on the experience of the senior author (R.F.S.) in the treatment of more than 130 spinal cord vascular lesions and based on a thorough review of the relevant literature, the authors propose a modified classification system for spinal cord vascular lesions. Lesions are divided into three primary or broad categories: neoplasms, aneurysms, and arteriovenous lesions. Neoplastic vascular lesions include hemangioblastomas and cavernous malformations, both of which occur sporadically and familially. The second category consists of spinal aneurysms, which are rare. The third category, spinal cord arteriovenous lesions, is divided into arteriovenous fistulas and arteriovenous malformations (AVMs). Arteriovenous fistulas are subdivided into those that are extradural and those that are intradural, with intradural lesions categorized as either dorsal or ventral. Arteriovenous malformations are subdivided into extradural-intradural and intradural malformations. Intradural lesions are further divided into intramedullary, intramedullary-extramedullary, and conus medullaris, a new category of AVM. This modified classification system for vascular lesions of the spinal cord, based on pathophysiology, neuroimaging features, intraoperative observations, and neuroanatomy, offers several advantages. First, it includes all surgical vascular lesions that affect the spinal cord. Second, it guides treatment by classifying lesions based on location and pathophysiology. Finally, it eliminates the confusion produced by the multitude of unrelated nomenclatural terms found in the literature.

Acute flank pain: an unusual presentation of a spinal AVM

The authors report the case of a 6-year-old boy with a spinal cord arteriovenous malformation (AVM) who presented with acute flank pain and a delayed onset of paraplegia. An early diagnosis of a spinal cord AVM was made difficult by the absence of neurological findings on initial evaluation. Included is a description of his clinical course, and the presentation of spinal AVMs to the emergency physician is discussed.

Dural arteriovenous shunts at the craniocervical junction

OBJECT

A retrospective analysis was conducted of 10 patients (three women and seven men) who were treated for spinal dural arteriovenous shunts (AVSs) located at the craniocervical junction. This analysis was performed to evaluate the characteristics of this unusual location in contrast with those of the more common thoracic and lumbar AVSs.

METHODS

Seven patients presented with subarachnoid hemorrhage (SAH) and one with slowly progressive quadriparesis and dyspnea due to myelopathy. The other two cases were detected incidentally and included a transverse-sigmoid dural AVS and a cerebellar arteriovenous malformation. Angiographic studies revealed that the spinal dural AVSs at the C-1 and/or C-2 levels were fed by the dural branches of the radicular arteries that coursed from the vertebral artery and drained into the medullary veins. Venous drainage was caudally directed in the patient with myelopathy. In contrast, the shunt flow drained mainly into the intracranial venous system in patients with SAH. Furthermore, in four of these patients a varix was found on the draining vein. In all patients, the draining vein was interrupted surgically at the point at which this vessel entered the intradural space, using intraoperative digital subtraction angiography to monitor flow. The postoperative course was uneventful in all patients and no recurrence was confirmed on follow-up angiographic studies obtained in seven patients at 6 months after discharge.

CONCLUSIONS

If computerized tomography scanning shows SAH predominantly in the posterior fossa and no abnormalities are found on intracranial four-vessel angiographic study, proximal vertebral angiography should be performed to detect dural AVS at the craniocervical junction. The results of surgical intervention for this disease are quite satisfactory.

Vascular decompression of a vertebral artery loop producing cervical radiculopathy. Case report

Vertebral artery tortuosity and loop formation are rare causes of cervical radiculopathy. The authors present the case of a 70-year-old man with 9 years of progressive right-sided cervical and scapular pain but no history of trauma. Computerized tomography myelography and magnetic resonance imaging revealed an ovoid mass in the right C3-4 intervertebral foramen. The patient underwent a right C-3 and C-4 hemilaminectomy and a complete C3-4 facetectomy. A pulsatile vascular structure was found compressing the right C-4 nerve root. The bone overlying the vascular structure was removed, producing decompression of the nerve root. Immediate postoperative angiography showed that this lesion was a focal vertebral artery loop. The patient's symptoms resolved after surgery, supporting the use of vascular decompression of a cervical nerve root compressed by a vertebral artery loop for the relief of radicular symptoms.

Transcondylar approach for dural arteriovenous fistulas of the cervicomedullary junction

BACKGROUND

Spinal dural arteriovenous fistulas are abnormal arteriovenous connections on the surface of the dura. The site of the fistula is most commonly in the thoracic and lumbosacral regions and they are rarely located in the cervical region.

CASES

The patients had two asymptomatic dural arteriovenous fistulas of the cervicomedullary junction fed by the left posterior meningeal artery and draining to the dilated coronal venous plexus and the radiculomedullary vein.

RESULTS

The lesions were successfully treated by surgical interruption of the intrathecal vein with coagulation via a suboccipital transcondylar approach and a condylar fossa approach. Both patients left the hospital without significant deficits.

CONCLUSIONS

We recommend that dural arteriovenous fistulas in the cervical region be surgically treated.

A cervical dural arteriovenous fistula in a patient presenting with radiculopathy. Case report

A 51-year-old man presenting with radiculopathy a rare cervical dural arteriovenous fistula (AVF) is reported. Angiography revealed that the cervical dural AVF was fed mainly by the left C-3 and C-4 radicular arteries and drained into the internal vertebral venous plexus with no communication with intradural structures. The dural AVF was treated surgically after embolization therapy. Although the AVF showed mass effect on computerized tomography (CT) scanning, abnormal vessels, which were suspected to drain the AVF, were observed intraoperatively to compress the left C-4 and C-5 nerve root sleeves. After resection of these abnormal epidural vessels, monoparesis of the left proximal upper extremity was markedly improved. In this patient, dynamic CT scanning was useful in the initial diagnosis, and the preoperative embolization therapy was very effective.

Delayed recanalization of a cerebral arteriovenous malformation following angiographic obliteration with polyvinyl alcohol embolization

BACKGROUND

The efficacy of embolization of cerebral arteriovenous malformations (AVMs) is presently being evaluated. Embolization of single pedicle AVMs may produce complete angiographic obliteration and has been suggested as the sole therapy for treating these lesions.

METHODS

A 17-year-old female presented with a left intraventricular and intraparenchymal cerebral hemorrhage resulting from a 1 cm left posterior choroidal AVM. She subsequently underwent polyvinyl alcohol (PVA) embolization of the AVM with complete angiographic obliteration.

RESULTS

At 9 months follow-up, no evidence of recanalization of the AVM nidus was seen. Two years later, recanalization of the nidus was seen; and the patient received radiosurgical treatment. The natural history of previously embolized AVMs is reviewed and the mechanisms for recanalization are discussed.

CONCLUSION

We recommend that patients with angiographic obliteration of AVMs receive further treatment, preferably resection, or be followed with serial angiography.