Vertebrobasilar insufficiency. Part 1: Microsurgical treatment of extracranial vertebrobasilar disease

Vascular reconstruction related to the extracranial vertebral artery: the presentation of the concept and the basis for the establishment of the bypass system

The intracranial vertebrobasilar artery system has a unique hemodynamic pattern (vessel trunk converged bilateral flow with three groups of perforators directly arising from it), is embedded within intense osseous constraints, and is located far from conventional donor vessels. Two major traditional modalities of posterior circulation revascularization encompass the superficial temporal artery to the superior cerebellar artery and the occipital artery to the posteroinferior cerebellar artery anastomosis, which are extracranial-intracranial low-flow bypass with donor arteries belonging to the anterior circulation and mainly supply focal perforators and distal vascular territories. As our understanding of flow hemodynamics has improved, the extracranial vertebral artery-related bypass has further evolved to improve the cerebral revascularization system. In this article, we propose the concept of "vascular reconstruction related to the extracranial vertebral artery" and review the design philosophy of the available innovative modalities in the respective segments. V1 transposition overcomes the issue of high rates of in-stent restenosis and provides a durable complementary alternative to endovascular treatment. V2 bypass serves as an extracranial communication pathway between the anterior and posterior circulation, providing the advantages of high-flow, short interposition grafts, orthograde flow in the vertebrobasilar system, and avoiding complex skull base manipulation. V3 bypass is characterized by profound and simultaneous vascular reconstruction of the posterior circulation, which is achieved by intracranial-intracranial or multiple bypasses in conjunction with skull base techniques. These posterior circulation vessels not only play a pivotal role in the bypass modalities designed for vertebrobasilar lesions but can also be implemented to revascularize the anterior circulation, thereby becoming a systematic methodology.

Current Open Surgical Indications for Revascularization in Cerebral Ischemia

Cerebral revascularization was pioneered half a century ago. Gradual improvements in microsurgical instrumentation and training in microsurgical techniques have allowed significant changes that improved outcomes in neurosurgery, extrapolating this knowledge to other neurosurgical diseases (brain tumor, aneurysms, and skull base tumor surgery). But the popularity of cerebral bypass procedures was followed by their decline, given the lack of clear benefit of bypass surgery in chronic cerebrovascular ischemia after the EC-IC bypass studies. Over the last couple of decades, the formidable advance of neuro-endovascular techniques for revascularization has lessened the need for application of open cerebral revascularization procedures, either for flow augmentation or flow replacement. However, there is still a select group of patients with chronic cerebral ischemia, for whom open cerebral revascularization with flow augmentation is the only treatment option available, and this will be the objective of our current review.

Descending Branch of the Lateral Circumflex Femoral Artery Graft for Posterior Inferior Cerebellar Artery Revascularization

BACKGROUND

Posterior inferior cerebellar artery (PICA) revascularization can be achieved with relative ease when a contralateral PICA is present. However, without a contralateral PICA, identification of a suitable vessel alternative can be challenging due to a size mismatch.

OBJECTIVE

To propose the descending branch of the lateral circumflex femoral artery (DLCFA) to be an acceptable, if not preferred, arterial graft for PICA revascularization.

METHODS

Data from patients who underwent PICA revascularization with DLCFA grafts were obtained from an institutional review board-approved prospectively maintained database with informed consent from the patients.

RESULTS

Three patients, all presenting with ruptured aneurysms, were treated with PICA revascularization using the DLCFA. All cases achieved bypass patency and no ischemic events occurred during the bypass procedures. Graft spasm occurred in 2 patients. Two patients that presented with neurological deficits achieved excellent neurological outcomes and 1 suffered an anterior spinal artery stroke during a repeat endovascular treatment 1 wk after revascularization.

CONCLUSION

The DLCFA is favorable for PICA revascularization when a contralateral PICA is not a viable option.

Occipital Artery to Extradural Vertebral Artery Bypass for Posterior Circulation Ischemia

BACKGROUND

Posterior circulation ischemic strokes can have devastating consequences, despite medical therapies. Extracranial–intracranial bypass for the augmentation of flow is a treatment option for selected patients with hemodynamic compromise and recurrent ischemia. However, posterior circulation bypass carries a higher risk and lower patency rate than bypass with anterior circulation.

OBJECTIVE

To present the occipital artery to the extradural vertebral artery (OA-eVA) bypass for posterior circulation ischemia.

METHODS

We retrospectively reviewed our experience of the OA-eVA bypass surgery in the treatment of bilateral vertebral steno-occlusive disease.

RESULTS

Seventeen patients were identified. Thirteen patients had bilateral vertebral artery (VA) occlusion (type I), while 4 patients had VA occlusion with contralateral VA severe stenosis (type II). All patients had cerebellar or pons infarction, for which the postoperative bypass patency rate was 100%, with carotid angiogram demonstrating excellent filling of the rostral basilar system or the posterior inferior cerebellar artery territory. The long-term follow-up outcome was favorable (modified Rankin score of 0-2) in 82% of patients (7 patients had complete resolution and 7 had improvement of symptoms) and unfavorable in 18%. One type II case without previous endovascular therapy developed recurrent ischemic onset associated with bypass occlusion.

CONCLUSION

OA-eVA bypass is a minimally invasive and effective alternative to posterior circulation ischemia. It provides sufficient blood flow augmentation to the vertebrobasilar territory. The advantages of this novel therapeutic strategy include avoiding performing craniotomy and deep bypass and achieving shorter operative times compared to conventional bypass surgery.

Balloon-expandable stent angioplasty in the treatment of vertebral artery stenosis in the V2 segment

Introduction

Vertebral artery stenosis is a major cause of posterior circulation ischemia in the elderly. There is not a clear consensus on the optimal therapeutic approach for symptomatic extracranial vertebral artery stenosis.

Aim

To evaluate the feasibility and efficacy of balloon-expandable stent angioplasty in the treatment of vertebral artery stenosis in the V2 segment.

Material and methods

Five patients with vertebral artery stenosis (V2 segment) and treatment of percutaneous transluminal stenting from July 2009 to June 2014 were retrospectively evaluated. All patients underwent color Doppler, transcranial color Doppler (TCD), CT angiography (CTA) and cerebral digital subtraction angiography (DSA) preoperatively. Whether there was osseous oppression was determined according to neck computed tomography (CT) and CTA. After the surgery, angiography was performed to determine if there was infarction or bleeding in the intracranial vertebral artery, basilar artery and posterior cerebral artery. The surgical parameters, residual stenosis, complications, etc. were recorded and evaluated. The patients were followed up accordingly.

Results

Five patients (3 males, 2 females; average age of 66 ±4.2, range of 54–75) were enrolled in the study. Balloon-expandable stents were successfully implanted in the 5 patients. The mean residual stenosis after the balloon-expandable stenting (preoperative: average, 87.0 ±6.6%, range: 75–93%) was 12.6 ±7.8% (range: 5–25%). The clinical symptoms disappeared or receded. No serious complications occurred.

Conclusions

The balloon-expandable stent angioplasty seemed to be feasible and efficacious in treating vertebral artery stenosis in the V2 segment. Further study with a large sample size is needed.

A review of the diagnosis and management of vertebral basilar (posterior) circulation disease

We have reviewed the English literature published in the last 70 years on Diseases of the Vertebral Basilar Circulation, or Posterior Circulation Disease (PCD). We have found that errors have been made in the conduct and interpretation of these studies that have led to incorrect approaches to the management of PCD. Because of the difficulty in evaluating the PC, the management of PCD has been incorrectly applied from anterior circulation disease (ACD) experience to PCD. PCD is a common form of stroke affecting 20-40% patients with stroke. Yet, the evidence is strong that the Anterior Circulation (AC) and Posterior Circulations (PC) differ in their pathology, in their clinical presentations, in the rapidity of development of symptoms, in optimal imaging methods, and in available treatments. There appears to be two categories of patients who present with PCD. The first, acute basilar artery occlusion has a more rapid onset. The diagnosis must be made quickly and if imaging proves a diagnosis of Basilar Artery Occlusion (BAO), the treatment of choice is Interventional removal of the basilar artery thrombosis or embolus. The second category of PCD and the most commonly seen PCD disease process presents with non-specific symptoms and early warnings of PCD that now can be related to ischemic events in the entire PC vessels. These warning symptoms and signs occur much earlier than those in the AC. IA angiography is still the gold standard of diagnosis and is superior in definition to MR and CT angiography which are commonly used as a convenient screening imaging tool to evaluate PCD but are both inferior to IA angiography in definition for lesions below 3-4 mm. In at least two reported studies 7T MR angiography appears superior to other imaging modalities and will become the gold standard of imaging of PCD in the future. Medical treatments applied to the ACD have not been proven of value in specific forms of PCD. Interventional therapy was promising but of unproven value in Randomized Controlled Trials (RCT) except for the treatment of Basilar Artery Occlusion (BAO). Surgical revascularization has been proved to be highly successful in patients, who are refractory to medical therapy. These studies have been ignored by the scientific community basically because of an incorrect interpretation of the flawed EC-IC Bypass Trial in 1985 as applying to all stroke patients. Moreover, the EC-IC Bypass Study did not include PCD patients in their study population, but the study results were extrapolated to patients with PCD without any scientific basis. This experience led clinicians to an incorrect bias that surgical treatments are of no value in PCD. Thus, incorrectly, surgical treatments of PCD have not been considered among the therapeutic possibilities for PCD. QMRA is a new quantitative MR technique that measures specific blood flow in extra and intracranial vessels. QMRA has been used to select those patients who may benefit from medical, or interventional, or surgical treatment for PCD based on flow determinations with a high success rate. QMRA accurately predicts the flows in many large and small vessels in the PC and AC and clearly indicates that both circulations are intimately related. From medical and surgical studies, the longer one waits for surgical treatment the higher the risk of a poor outcome results. This observation becomes obvious when the rapidity of development of PCD is compared with ACD. Recent advances in endovascular therapy in the treatment of acute basilar thrombosis is a clear sign that early diagnosis and treatment of PCD will reduce the morbidity and mortality of these diseases. In this review it is evident that there are multiple medical and surgical treatments for PCD depending upon the location of the lesion(s) and the collateral circulation demonstrated. It is clear that the AC and PC have significant differences. With the exception of the large population studies from Oxford England, the reported studies on the management of PCD in the literature represent small selected subsets of the universe of PC diseases, the information from which is not generalizable to the universe of PCD patients. At this point in the history of PCD, there are not large enough databases of similar patients to provide a basis for valid randomized studies, with the exception of the surgical studies. Thus, a high index of suspicion of the early warning symptoms of PCD should lead to a rapid individual clinical assessment of patients selecting those with PCD. Medical, interventional, and/or surgical treatments should be chosen based on knowledge presented in this review. Recording the results in a national Registry on a continuing basis will provide the data that may help advance the management of PCD based on larger data bases of well documented patient information to guide the selection of future therapies for PCD treatments. It is also clear that the management of patients within the complex of diseases that comprise PCD should be performed in centers with expertise in the imaging, medical, interventional and surgical approaches to diseases of the PCD.

Technical factors affecting outcomes following endovascular treatment of posterior circulation atherosclerotic lesions

Background

Atherosclerotic disease of the vertebrobasilar system causes significant morbidity and mortality. All lesions require aggressive medical management, but the role of endovascular interventions remains unsettled. This study examines such endovascular interventions for vertebrobasilar atherosclerosis.

Methods

Retrospective review was performed of prospectively maintained procedure logs at three hospitals with comprehensive neurointerventional services. Patients with angiographically-proven stenosis undergoing elective stent placement were selected for analysis of demographic factors, lesion characteristics, and treatment details. Multivariate analysis was performed to evaluate for associations with ischemic stroke, death, and functional status as measured by modified Rankin scale at multiple intervals.

Results

One hundred and twenty-three lesions were treated in 110 patients. A total of 43 (58.1%) lesions caused stroke, while 66 (89.2%) caused transient ischemic attacks (TIAs). Forty lesions (32.5%) were at the vertebral origin; 97 (60.2%) were intracranial. A total of 112 (91.1%) were treated successfully. 4 (3.3%) of 10 (8.1%) procedural complications were symptomatic. Intracranial lesions were associated with death at 1 and 2 years (OR 24.91, P < 0.001) and mRS >2 at last contact (OR 12.83, P < 0.001). Stenting treatment with conjunctive angioplasty had lower rates of death (OR 0.303, P = 0.046) and mRS >2 at last contact (OR 0.234, P = 0.018) when angioplasty was performed with a device other than that packaged with the stent.

Conclusion

Endovascular treatment of vertebrobasilar atherosclerosis can be performed safely, particularly for vertebral origin lesions. Higher rates of technical failure and complication may be acceptable for certain intracranial lesions due to their refractory nature and the morbidity caused by such lesions. Treatment should be tailored to features of each individual lesion.

Surgical Treatment of Rotational Vertebral Artery Syndrome Induced by Spinal Tumor: A Case Report and Literature Review

Vertebrobasilar insufficiency (VBI) provoked by physiological head rotation is known as rotational vertebral artery syndrome (RVAS) or Bow Hunter syndrome. RVAS most often occurs at C1–2 level with head rotation and presents with symptoms of VBI. Several previously published studies have reported RVAS at subaxial sites (V2 segment), however, tumor-induced RVAS has never been reported. The authors report the first case of RVAS at V2 segment due to compression from a spinal tumor. A 71-year-old man presented with symptoms of dizziness provoked by head rotation or neck extension. computed tomography (CT) angiography and dynamic cerebral angiography revealed circumferential stenosis with neutral neck position and complete occlusion of the left dominant vertebral artery (VA) at C5 level with his neck extended or rotated to the left. Complete neurological recovery was achieved after removal of a spinal osteochondroma and surgical decompression of the left VA via an anterior approach. Spinal tumors should be included in the differential diagnosis in cases of RVAS. Spinal degenerations or sarcomatous transformation of the tumor could lead to clinical manifestations of RVAS in cases with spinal osteochondroma. Complete removal of the tumor with or without spinal fusion would be the treatment of choice, in addition to medical treatment in the cases of acute stroke.

The role of alternative anastomosis sites in occipital artery–posterior inferior cerebellar artery bypass in the absence of the caudal loop using the far-lateral approach

OBJECTIVE

Occipital artery–posterior inferior cerebellar artery (OA-PICA) bypass is a technically challenging procedure for posterior fossa revascularization. The caudal loop of the PICA is considered the optimal site for OA-PICA anastomosis, however its absence can increase the technical difficulty associated with this procedure. The use of the far-lateral approach for accessing alternative anastomosis sites in OA-PICA bypass in patients with absent or unavailable caudal loops of PICA is evaluated.

METHODS

A morphometric analysis of OA-PICA bypass with anastomosis on each segment of the PICA was performed on 5 cadaveric specimens through the conventional midline foramen magnum and far-lateral approaches. The difficulty level associated with anastomoses at each segment was qualitatively assessed in each approach for exposure and maneuverability by multiple surgeons. A series of 8 patients who underwent OA-PICA bypass for hemodynamic ischemia or ruptured dissecting posterior fossa aneurysms are additionally reviewed and described, and the clinical significance of the caudal loop of PICA is discussed.

RESULTS

Anastomosis on the caudal loop could be performed more superficially than on any other segment (p < 0.001). A far-lateral approach up to the medial border of the posterior condylar canal provided a 13.5 ± 2.2–mm wider corridor than the conventional midline foramen magnum approach, facilitating access to alternative anastomosis sites. The far-lateral approach was successfully used for OA-PICA bypass in 3 clinical cases whose caudal loops were absent, whereas the midline foramen magnum approach provided sufficient exposure for caudal loop bypass in the remaining 5 cases.

CONCLUSIONS

The absence of the caudal loop of the PICA is a major contributing factor to the technical difficulty of OA-PICA bypass. The far-lateral approach is a useful surgical option for OA-PICA bypass when the caudal loop of the PICA is unavailable.

Effectiveness of Intracranial Percutaneous Transluminal Angioplasty or Stenting for Atherosclerotic Vertebrobasilar Artery Occlusion in the Acute Phase of Ischemic Stroke

OBJECTIVE

Although short-term clinical outcomes after basilar artery stent placement have been reported previously, effectiveness of intracranial stenting for vertebrobasilar artery occlusion in the acute phase of ischemic stroke is unclear.

METHODS

We clinically investigated 8 patients with intracranial percutaneous transluminal angioplasty (PTA) or stenting as our protocol for symptomatic atherosclerotic vertebrobasilar artery occlusion (age range, 54-80 years; mean age, 69 ± 11 years; 6 men and 2 women) who were admitted to our hospital between August 2013 and December 2015.

RESULTS

Two patients underwent PTA of the vertebrobasilar artery 2-5 months before stent placement. The other 6 patients underwent intracranial stenting just after PTA. Within the first 30 days after vertebrobasilar artery stent placement, 2 ischemic stroke complications affected patients. Ischemic complications were significantly associated with prestent lesion lumen greater than 0.5 mm. The modified Rankin Scale score and clinical outcome were significantly associated with complications. Clinical outcomes correlate with ischemic complications and vertebrobasilar anatomy.

CONCLUSIONS

Stent angioplasty may be a reasonably good treatment option for patients with technically favorable lesions, especially in vertebrobasilar atherosclerotic occlusion with medically or PTA only refractory symptoms. Despite a significant complication rate, most of our patients experienced good to excellent clinical outcomes and were free of vertebrobasilar ischemia at late midterm follow-up.

Intracranial Stenting for Cerebrovascular Pathology

After reading this article, the participant should be able to:

Describe the use of stent-assisted angioplasty for intracranial atherosclerotic disease. Recall the present status of stent-assisted managment of intracranial aneurysms. Describe the role of stenting and its technical aspects in the treatment of arteriovenous fistulae and acute stroke.

Stenting for Stenoses of the Proximal Vertebral Artery

We report our initial experience of stenting for symptomatic stenoses of the proximal vertebral artery. A total of 25 lesions affecting the proximal vertebral artery were treated by PTA with stent in 23 patients. The lesions involved the vertebral artery ostium in 20 lesions and the nonostial V1 portion in five lesions. The mean stenosis rate of those lesions was 81% pre-stenting and was reduced to 4% post-stenting.

There were two transient neurological complications: hemiparesis in one patient and visual acuity disturbance in another. Angiographic follow-up studies more than three months after treatment demonstrated restenosis in three patients. One of these patients was symptomatic. These restenoses were successfully treated by PTA.

Our initial results demonstrated that stenting is a feasible and safe method of treating stenosis of the proximal vertebral artery.

[New surgical treatment for vertebral artery pseudoaneurysm at the boundary between the V2 and V3 segments]

The clinical case of a patient with a pseudoaneurysm of the left vertebral artery at the boundary between V(2) and V(3) segments after a stab wound to the neck is reported. The patient underwent a rare variant of surgical reconstruction of the vertebral artery, including resection of the vertebral artery pseudoaneurysm at the boundary between the V(2) and V(3) segments, the vertebrovertebral autovenous shunting (from the C(IV) vertebra to the C(I)-C(II) vertebrae with resection of the anterior wall of the vertebral artery canal). Postoperatively, SCT angiography revealed satisfactory blood flow in the shunt and improvement of the neurological status. The article provides a literature review on surgical procedures at the distal portion of the vertebral artery. The surgical technique was illustrated (intraoperative photos), demonstrating that the vertebral artery can be easily mobilized at any part of the V(2) segment with minimum damage to the adjacent tissues.

Vertebral artery transposition for revascularization of the posterior circulation: a critical assessment of temporary and permanent complications and outcomes

OBJECT

Despite advances in medical management and endovascular therapies, including the introduction of statins, antiplatelet agents, and drug-eluting stents, some patients experience medically refractory vertebrobasilar insufficiency and may benefit from robust surgical revascularization. The aim of this study was to evaluate such patients after surgical revascularization, emphasizing long-term outcomes and rates of complications.

METHODS

The authors retrospectively identified 22 patients (5 women and 17 men) whose mean age was 69.1 years (range 48-81 years) who underwent revascularization of the posterior circulation via a proximal vertebral artery-carotid artery transposition between 2005 and 2013. The patients' conditions before surgery were clinically summarized, and long-term outcomes and complication rates after surgery were evaluated.

RESULTS

All the patients were symptomatic before surgery although they received the best medical therapy as defined by their primary care physician. Presenting symptoms consisted of stroke, transient ischemic attacks (TIAs), and/or findings attributable to posterior circulation hypoperfusion. There were no deaths associated with revascularization surgery. The postoperative complication rate was 45.5%, which included 3 cases of recurrent laryngeal nerve palsy, 1 case of thoracic duct injury, 2 cases of TIA, and 4 cases of Horner's syndrome. The thoracic duct injury was identified intraoperatively and ligated without sequelae, all the TIAs resolved within 24 hours of surgery, all 4 sympathetic plexus injuries resolved, and all but 1 of the recurrent laryngeal nerve palsies resolved, resulting in a 4.5% complication rate in a mean follow-up period of 8.8 months. All the patients had resolution of their presenting symptoms, and a single patient had symptomatic restenosis that required stenting and angioplasty, resulting in a restenosis rate of 4.5%.

CONCLUSIONS

Despite the optimization of medical therapies and lifestyle modifications, a select subset of patients with posterior vascular circulation insufficiency remains. In the authors' experience, vertebral artery-carotid artery transposition provides a surgical option with relatively low long-term complication and restenosis rates that are comparable or lower than those reported with endovascular treatment.

Balloons in endovascular neurosurgery: history and current applications

The use of balloons in the field of neurosurgery is currently an essential part of our clinical practice. The field has evolved over the last 40 years since Serbinenko used balloons to test the feasibility of occluding cervical vessels for intracranial pathologies. Since that time, indications have expanded to include sacrificing cervical and intracranial vessels with detachable balloons, supporting the coil mass in wide-necked aneurysms (balloon remodeling technique), and performing intracranial and cervical angioplasty for atherosclerotic disease, as well as an adjunct to treat arteriovenous malformations. With the rapid expansion of endovascular technologies, it appears that the indications and uses for balloons will continue to expand. In this article, we review the history of balloons, the initial applications, the types of balloons available, and the current applications available for endovascular neurosurgeons.

[Vertebral artery dissection due to the C6 transverse process and laryngeal cartilage associated with vertebral artery anomaly]

A 52-year-old woman complained of the sudden onset of a left temporal headache, left neck stiffness and dizziness. Brain magnetic resonance imaging showed a high-intensity lesion in the right medial medulla. Dynamic cerebral angiography revealed vertebral artery dissection and compression at the C6 level due to a transverse process at the C6 level associated with rightward head rotation. Removal of bone and decompression of the vertebral artery were performed from the C5 to C6 levels. Intraoperasively, obstruction of blood flow due to a laryngeal cartilage that rotated with the passive rotation of the patient's head to the right was found. To the best of our knowledge this is the first reported case of vertebral artery occlusion due to a laryngeal cartilage associated with head rotation.

Observation of vertebral artery damage using angioscopy in autopsy cases

The vertebral arteries are important blood vessels that supply the cerebral circulation in conjunction with the internal carotid arteries. In cases of subarachnoid hemorrhage, it is necessary to examine the vertebral arteries as potential sources of bleeding due to blunt trauma (head and neck) or of cerebral embolism that originated on the surface of the damaged intima as a result of hyperflexion or hyperextension. However, a considerable part of the vertebral arterial surface is surrounded by bone, resulting in challenges during examination in a routine autopsy. In this study, angioscopy was used to inspect the vertebral artery intima for damage in cases of neck injury, head injury, or neck strangulation. Intimal damage was detected in 34 out of the total 75 cases. Of the 28 cases with cervical discopathy or fracture, 61% had intimal damage. In addition, postmortem application of computed tomography angiography was performed to identify the injured vessel in a case with traumatic subarachnoid hemorrhage, and a perforated hole was detected using angioscopy, which did not introduce autopsy-related artifacts. Therefore, angioscopy may be a useful and nondestructive method to identify intimal damage in the vertebral arteries during an autopsy.

Rotational vertebral artery occlusion secondary to adjacent-level degeneration following anterior cervical discectomy and fusion

Rotational vertebral artery occlusion (RVAO), or bow hunter's syndrome, most often occurs at the C1-2 level on physiological head rotation. It presents with symptoms of vertebrobasilar insufficiency (VBI). Several previously published studies have reported on subaxial sites of vertebral artery (VA) compression by head rotation. The authors report a case of subaxial spine RVAO due to adjacent-segment degeneration. A 52-year-old man presented with dizziness when rotating his head to the left. Twenty years earlier, he had undergone a C4-5 anterior cervical discectomy and fusion (ACDF) for a herniated disc. Imaging studies including a dynamic CT angiography and dynamic catheter angiography revealed occlusion of the left VA at the C3-4 level when the patient turned his head to the left, in the setting of an aberrant vertebrobasilar system. Successful treatment was achieved by surgical decompression of the left VA and C3-4 ACDF. Expedited diagnosis and treatment are dependent on the recognition of this unusual manifestation of RVAO, especially when patients present with nonspecific symptoms of VBI.

Advances and Innovations in Revascularization of Extracranial Vertebral Artery

Revascularization of the extracranial vertebral artery has evolved significantly since the adoption of endovascular techniques. The current neurosurgical armamentarium includes microsurgical and endovascular approaches. The indications for each treatment modality, however, still need to be further delineated. In contrast to carotid artery endarterectomy and carotid artery angioplasty/stenting, there is limited comparative evidence on the efficacy of medical, open, and endovascular treatment of atherosclerotic disease of the extracranial vertebral artery. More recently, drug-eluting stents have gained momentum after high rates of in-stent restenosis have been reported with bare metal stents placed in the vertebral artery. In this article, we discuss the indications, clinical assessment, and surgical nuances of microsurgical and endovascular revascularization for atherosclerotic disease of the extracranial vertebral artery. Despite a general tendency to consider endovascular treatment in the majority of patients, ultimately, open and endovascular revascularization of extracranial vertebral artery should be regarded as complementary therapies and both treatment options need to be discussed in selected patients.

Percutaneous Treatment of Vertebral Artery Stenosis

Endovascular treatment of the ostial and proximal portions of the vertebral artery is a safe and effective technique for alleviating symptoms and improving cerebral blood flow to the posterior circulation. Vertebral artery angioplasty can be performed with high technical and clinical success rates, low complication rates, and durable long-term results. Although restenosis rates range from 0% to 48%, the durability of vertebral artery angioplasty is evidenced by low restenosis rates in multiple large series reported in the literature using multiple treatment options, including balloon angioplasty alone, bare metal stents, and drug-coated stents.

Recanalization of symptomatic vertebral ostial occlusion in patients with acute or subacute stroke

SUMMARY

Vertebral artery recanalization in symptomatic stenosis/occlusion remains controversial, as no definite evidence exists regarding this topic. There are only a few reports regarding the feasibility and safety of recanalization in the first segment of the vertebral artery with atherosclerotic vertebral ostial occlusion. We report our experience treating first segment occlusion in 8 patients and present a balloon protection technique used to reduce the thromboembolic burden during the stent placement procedure. The outcome at 3 months showed an mRS ≤2 except for a patient with a poor initial status with basilar artery occlusion. Revascularization of a rather long first segment occlusion is technically feasible and can be safely performed by use of embolic protection methods.

Cervical and upper mediastinal lymph node metastasis from gastrointestinal and pancreatic neuroendocrine tumors: true incidence and management

BACKGROUND

The incidence, clinical importance, and optimal management of cervical and upper mediastinal lymph node metastasis from gastrointestinal and pancreatic neuroendocrine tumors (NETS) are largely unknown. Historically, cervical nodes have been regarded as asymptomatic and ignored. We hypothesized that these lesions have clinical implications and should be removed surgically.

STUDY DESIGN

Consecutive (111)In pentetreotide scans (OctreoScan) performed at our institution from May 2008 to October 2010 were reviewed to determine the incidence of cervical and upper mediastinal lymph node metastases among patients with gastrointestinal and pancreatic NETs. The charts of surgically treated patients were reviewed to evaluate the clinical importance of these metastases and the subsequent outcomes of their surgical treatment.

RESULTS

A total of 161 NET patients presented with positive OctreoScans. Fourteen patients (8.7%) scanned positive for cervical and upper mediastinal lymph node metastasis. Nine patients underwent surgical exploration; 8 had successful removal of their metastatic nodes. Seven had clinical symptoms that resolved after surgery.

CONCLUSIONS

Cervical and upper mediastinal lymph node metastases from gastrointestinal and pancreatic NETs were seen in up to 8.7% of patients. In the past, these metastases were assumed to be insignificant and ignored. Our study clearly demonstrates that most, if not all, such metastases are symptomatic and their clinical implications should not be overlooked. Notably, these metastases can be easily and safely resected using radioguided surgery.

Stent placement for atherosclerotic stenosis of the vertebral artery ostium: angiographic and clinical outcomes in 117 consecutive patients

BACKGROUND

Although it is thought to be a safe treatment option, the main concerns related to treating vertebral artery ostium (VAO) stenosis with stents have been the rate of restenosis and the uncertain long-term results.

OBJECTIVE

To evaluate the angiographic and clinical results of stent placement for atherosclerotic stenosis of the VAO.

METHODS

One hundred seventeen consecutive patients with atherosclerotic VAO stenosis were treated with stent placement over a period of 12 years. All patients were retrospectively analyzed through the use of a prospectively collected database. The indication criteria for this treatment protocol were symptomatic severe VAO stenoses (> 60%) and asymptomatic severe VAO stenoses (> 60%) with incidentally detected infarction in the posterior circulation. The target diameter of stent dilatation from 1997 to 2000 was the normal vessel diameter just distal to the lesion. Moderate overdilation in the proximal portion of the stents has been performed since 2001.

RESULTS

Successful dilatation was obtained in 116 of 117 cases. Transient neurological complications developed in 2 patients; however, no patients experienced any permanent neurological complications. One hundred four patients underwent follow-up angiography at 6 months after stenting. The restenosis rate at the 6-month follow-up was 9.6% (10 of 104). Until 2000, the restenosis rate after stenting was 13.3%. Since 2001, the restenosis rate has decreased to 4.5%. The median clinical follow-up period was 48 months. The annual rate of strokes in the posterior circulation was 0.95%.

CONCLUSION

Stent placement for atherosclerotic VAO stenosis is considered to be a feasible and safe treatment and may be effective for stroke prevention. The moderate overdilation of stents may be an effective modality for the prevention of restenosis.

Rotational vertebral artery occlusion-series of 9 cases

BACKGROUND

Rotational vertebral artery syndrome (RVAS) is a rare entity about which previously published studies are mostly limited to individual case reports.

OBJECTIVE

To report our decade-long experience with this syndrome in 9 patients with compression ranging from the occiput to C6.

METHODS

We utilized a posterior approach for lesions rostral to C4 and an anterior approach for lesions at or caudal to C4. Furthermore, we demonstrated the feasibility and efficacy of a minimally invasive posterior cervical approach. Patient profile, operative indications, surgical approach, operative findings, complications, and long-term follow-up were reviewed and discussed.

RESULTS

Average follow-up was 47 months. All procedures provided excellent outcomes by Glasgow Outcome Scale scores. The anterior approach had significantly less blood loss (187.5 mL vs 450 mL, P = .00016) and shorter hospitalization length (2 days vs 4.5 days; P = .0001) compared with the far-lateral approach. There was one complication of cervical instability in the far-lateral approach cohort. As an alternative to the far-lateral surgery, a minimally invasive approach resulted in shorter hospitalization (2 days) and less blood loss (10 mL) while avoiding the complication of cervical instability.

CONCLUSION

We demonstrated the safety, efficacy, and durability of 3 surgical approaches for RVAS. Proper examination, preoperative imaging, and surgical planning were necessary for a satisfactory outcome.

Vertebral Artery Origin Stents Revisited

BACKGROUND

Vertebral origin angioplasty and stenting (VOAS) with bare metal stents is associated with a high rate of in-stent restenosis (ISR).

OBJECTIVE

We evaluated the rate of ISR after VOAS with drug-eluting stents.

METHODS

Twenty patients (15 men, 5 women; age range, 36–88 years; mean, 63.7 years) were treated for VOAS with a paclitaxel-eluting stent (Taxus Express2, Boston Scientific, Natick, Massachusetts). Stenosis at follow-up was quantified as insignificant (0%–24%), mild (25%–49%), moderate (50%–74%), and severe (75%–100%). ISR was defined using a binary criteria of &gt; 50% stenosis at follow-up angiography.

RESULTS

All procedures were technically successful with no periprocedural complications. Follow-up angiography (range, 4–48 months; mean, 14.7 months) showed insignificant stenosis in 9 patients, mild in 6, moderate in 4, and severe in 1. In 1 patient with “moderate” stenosis, the stent migrated distally; therefore, the lesion restenosis was not within the stent. Thus, 4 of 19 patients (21%) exhibited binary moderate or severe ISR, and 5 of 20 showed restenosis at the lesion (25%). The patient with severe stenosis developed stent thrombosis &gt; 3 years after VOAS.

CONCLUSION

VOAS with drug-eluting stents was associated with a low incidence of periprocedural complications. Although the rate of restenosis was half that seen with the use of bare metallic stents, 21% of patients still developed moderate or severe ISR. These patients may require ≥ 1 revascularization procedures. The risk of delayed stent thrombosis may necessitate lifelong dual antiplatelet medications.

Endovascular stenting for vertebral artery stenosis

OBJECTIVES

The aim of this study was to demonstrate the safety and long-term durability of catheter-based therapy for symptomatic vertebral artery stenosis (VAS).

BACKGROUND

Symptomatic VAS carries with it a 5-year 30% to 35% risk of stroke. The 2-year mortality approaches 30% for medically managed strokes involving the posterior circulation. Surgical bypass is rarely performed, due to high morbidity and mortality. Endovascular revascularization with primary stenting offers an attractive treatment option for these patients.

METHODS

One-hundred five consecutive symptomatic patients (112 arteries, 71% male) underwent stent placement for extracranial (91%) and intracranial (9%) VAS from 1995 to 2006. Fifty-seven patients (54%) had bilateral VAS, 71 patients (68%) had concomitant carotid disease, and 43 patients (41%) had a prior stroke.

RESULTS

Procedural and clinical success was achieved in 105 (100%) and 95 (90.5%) patients, respectively. One-year follow-up was obtained in 87 (82.9%) patients, of which 69 patients (79.3%) remained symptom-free. At 1 year, 6 patients (5.7%) had died and 5 patients (5%) had a posterior circulation stroke. Target vessel revascularization occurred in 7.4% at 1 year. At a median follow-up of 29.1 months (interquartile range 12.8 to 50.9 months), 13.1% underwent target vessel revascularization, 71.4% were alive, and 70.5% remained symptom-free.

CONCLUSIONS

In experienced hands, stenting for symptomatic VAS can be accomplished with a very high success rate (100%), with few periprocedural complications, and is associated with durable symptom resolution in the majority (approximately 80%) of patients. We conclude that endovascular stenting of vertebral artery atherosclerotic disease is safe and effective compared with surgical controls and should be considered first-line therapy for this disease.

Treatment of stenoses of vertebral artery origin using short drug-eluting coronary stents: improved follow-up results

BACKGROUND AND PURPOSE

Recent studies on stent placement of significant stenoses at the origin of the vertebral artery reported excellent immediate results. Long-term outcomes, however, were disappointing due to high restenosis rates and stent breakage. In the present study, we evaluated the application of a short drug-eluting balloon-expandable coronary stent for the endovascular treatment of these frequent lesions.

MATERIALS AND METHODS

In a period of 23 months, 48 patients (12 women, 36 men) with a mean age of 68 years (range, 46-82 years) harboring 52 significant ostial vertebral artery stenoses underwent treatment with short (8 mm) balloon-expandable paclitaxel-eluting coronary stents. Stents were deployed as closely as possible so that the proximal end was just at the origin of the vertebral artery, with high inflation pressure applied. Patients were under continuous medication with acetylsalicylic acid and clopidogrel before and after the treatment. Follow-up clinical assessment and angiography were performed in all patients.

RESULTS

Periprocedural complications were not encountered. Stenosis severity was reduced from 62 +/- 2% (mean +/- standard error of the mean) preprocedurally to 15 +/- 2% postprocedurally. Follow-up angiography at 7.7 +/- 0.6 months revealed a mean stenosis degree of 24 +/- 3%. None of the patients developed posterior circulation symptoms related to the treated segment during the follow-up period. Recurrent stenosis (>50%) at follow-up was found in 6 (12%) lesions.

CONCLUSIONS

Stent placement of significant ostial vertebral artery stenosis by using short drug-eluting stents is safe and yields good midterm patency rates and excellent protection from posterior circulation ischemia.

Positional vertebral artery compression and vertebrobasilar insufficiency due to a herniated cervical disc

The authors report a case of vertebrobasilar insufficiency caused by vertebral artery (VA) compression due to a herniated cervical disc, which was surgically treated with the aid of intraoperative angiography. This 78-year-old man visited the hospital because of syncope following head rotation. Admission CT scans revealed a calcified mass adjacent to the right lateral process of the C-4 spine. Cervical angiography demonstrated an obstruction of the right VA at this region on rotation of the head to the right. The operation revealed a cervical disc protruding toward the right VA. The disc was surgically removed, and then the decompression of the right VA was confirmed on intraoperative angiography studies. A histopathological examination showed fibrohyaline cartilage, indicating an ossified intervertebral disc. The postoperative course was uneventful, and he has not experienced any syncope since treatment. A cervical disc herniation could be a cause of vertebrobasilar insufficiency by exerting positional compression of the VA. Intraoperative angiography could be quite useful to confirm this condition during decompression surgery for a cervical VA.

Minimally invasive decompression of a suboccipital osseous prominence causing rotational vertebral artery occlusion. Case report

Surgical decompression of the vertebral artery (VA) between the suboccipital area and C-1 is typically performed via a large midline incision or a far-lateral approach. Such traditional open approaches are often associated with significant muscle dissection and blood loss. In this case, a 12-year-old boy suffered a stroke related to a VA rotational occlusion (bow hunter syndrome) and dissection due to a prominent suboccipital bone mass. Successful decompression of the VA was performed via a minimally invasive 22-mm tubular retractor. This is the first reported case report of a minimally invasive decompression of the VA between the skull base and C-1.

MICROSURGICAL REVASCULARIZATION OF PROXIMAL VERTEBRAL ARTERY

OBJECTIVE

High rates of restenosis after stenting to treat vertebral artery (VA) origin disease have revitalized interest in microsurgical revascularization for this condition. This study analyzes the outcomes of microsurgical revascularization used to treat proximal VA occlusive disease.

METHODS

Between 1986 and 2007, 29 patients (19 men, 10 women; age range, 35–93 years) underwent microsurgical revascularization for proximal VA disease. Their medical records were reviewed retrospectively for presenting symptoms, presence of comorbidities, target lesion characteristics, contralateral VA findings, procedure-related morbidity, and clinical and radiographic outcomes.

RESULTS

Thirteen, 7, and 6 patients underwent VA-to-carotid artery transposition, endarterectomy, or both, respectively. Two patients underwent subclavian endarterectomy plus vertebral endarterectomy, and 1 patient underwent carotid endarterectomy associated with VA transposition. There were no cases of periprocedural stroke or death. Permanent procedure-related neurological complications included 1 case of Horner's syndrome and 1 case of hoarseness. Two of the 27 patients available for follow-up had new neurological symptoms attributable to the vertebrobasilar system. Follow-up imaging was available for 14 patients, only 1 of whom developed restenosis, most likely related to disease progression at the site of anastomosis.

CONCLUSION

Microsurgical revascularization is a good alternative treatment for proximal VA occlusive disease. Randomized studies are needed to compare the efficacy of surgical revascularization and stenting, especially drug-eluting stents, for this indication.

Clinical and angiographic long-term outcomes of vertebral artery–subclavian artery transposition to treat symptomatic stenosis of vertebral artery origin

Object

Although angioplasty and stent placement for vertebral artery (VA)–origin stenosis have been performed using endovascular techniques, a high likelihood of restenosis has been observed in the long term. Therefore, the authors assessed the long-term clinical and angiographic outcomes in patients after VA–subclavian artery (SA) transposition.

Methods

Thirty-six patients (31 men, 5 women; mean age 64.3 years, range 46–76 years) underwent clinical evaluation (modified Rankin Scale [mRS]) and cervical angiographic evaluation preoperatively and within 1 month of and 6 months after VA-SA transposition undertaken to treat symptomatic stenosis of VA origin.

Results

Postoperative neurological deficits due to intraoperative brain ischemia did not occur, and MR imaging demonstrated no new postoperative ischemic lesions in any of the patients. One patient died of acute myocardial infarction 2 months after surgery and another developed a left thalamic hemorrhage (mRS score of 5) at 42 months postsurgery. None of the remaining 34 patients experienced further ischemic events, and the mRS score in all of these patients remained unchanged during a mean follow-up period of 54 months. The degree of VA-origin stenosis (preoperative mean 84%) was reduced to ≤ 30% after surgery (mean 2%). Long-term follow-up angiography in 29 patients (81%) revealed the absence of restenosis, defined as > 50% luminal narrowing, in all of them.

Conclusions

The clinical and angiographic long-term outcomes demonstrated here suggest that VA-SA transposition will be useful in patients with symptomatic stenosis of VA origin.

Safety and feasibility of drug-eluting stent implantation at vertebral artery origin: the first case series in Asians

BACKGROUND/PURPOSE

Studies of the safety and efficacy of drug-eluting stent (DES) implantation to treat vertebral artery (VA) ostial stenosis are lacking in the Asian population. The aim of this study was to evaluate the feasibility and safety of DES implantation to treat VA ostial stenosis in Asians.

METHODS

We retrospectively analyzed the medical and radiologic records of patients receiving VA origin stenting with DES from October 2004 to September 2006 in the National Taiwan University Hospital.

RESULTS

Eleven symptomatic patients (9 male; mean age, 72 years) with 11 lesions treated with DES were included. There were eight lesions treated with paclitaxel-eluting stents and three lesions treated with sirolimus-eluting stents. The success rate for implantation of a DES was 100%. The percentage of stenosis was significantly reduced after stenting (86+/-5 to 2+/-4%; p<0.001). No peri-interventional neurologic, vascular, or other medical complications were noted. All patients were asymptomatic at the mean follow-up time of 18.7+/-8.6 months (range, 6-30 months). Two patients received repeat angiography at 4 or 8 months after stenting. No significant in-stent restenosis was found.

CONCLUSION

Symptomatic VA origin stenosis can be treated safely and effectively with DES in Asians.

Subaxial positional vertebral artery occlusion corrected by decompression and fusion

STUDY DESIGN

A rare case of subaxial vertebral artery (VA) positional occlusion is reviewed and treatment methods discussed.

OBJECTIVE

The decision process involved in treating subaxial VA positional occlusion is reviewed.

SUMMARY OF BACKGROUND DATA

Bow Hunter stroke is a symptomatic vertebrobasilar insufficiency caused by stenosis or occlusion of the VA with physiologic head rotation. It most commonly occurs at the junction of C1 and C2 and less commonly as the VA enters the C6 transverse foramen. Rotational stenosis of the VA is quite rare during its passage through the foramen transversarium of C3-C6.

METHODS

A 48-year-old gentleman presented describing syncopal episodes when he turns his head to the left side. Imaging revealed a congenitally narrowed right foramen transversarium and high-grade stenosis of the left VA when the head was turned to the left. A routine anterior cervical discectomy and fusion was performed with the addition of decompression of the left transverse foramen.

RESULTS

Vascular imaging should be performed with the patient's head in both the neutral position and in the symptomatic position. Surgical treatment may be chosen if conservative therapies fail and generally has 1 of 2 goals-decompression of the VA or elimination of rotational movement at the affected level. Decisions between anterior and posterior decompressions may be influenced by the surgeon's comfort level with the approach and if the transverse foramen stenosis is caused mainly by an anterior (osteophytes at the uncinate process) or posterior (facet joint hypertrophy) process. The patient remains symptom-free after treatment.

CONCLUSION

This report demonstrates the condition in the subaxial spine and describes successful treatment by fusion of the affected level combined with decompression of the foramen transversarium-a combination of previously described therapies.

Vertebral artery decompression in a patient with rotational occlusion

We report a patient who suffered drop attacks during head reclination. Computer tomography of the cervical spine demonstrated a stenotic right vertebral artery at C4/5. However, Doppler ultrasonography of the vertebral artery showed no abnormality. Angiography confirmed complete occlusion of the left vertebral and a stenosis of the right vertebral artery. Dynamic angiography indicated occlusion of the stenotic region on the right side during reclination of the head. Surgery using a posterior approach with decompression of the vertebral artery, lead to an excellent outcome and the patient left the hospital without any symptoms. Therefore, in patients with drop attacks and normal ultrasonography, a stenosis of the vertebral artery caused by a spondylophytic compression could still be the cause. At worst, the stenosis could lead to brain infarction if left untreated. Dynamic angiography is crucial for the diagnosis and surgical decompression has excellent results.