Occipital artery to vertebral artery bypass for treatment of bilateral vertebral artery occlusion with QMRA as an adjunct to diagnostic assessment.

PURPOSE: Stroke, the second leading cause of death globally, often involves ischemia in the vertebrobasilar territory. This condition is underexplored, despite significant morbidity and mortality risks. The purpose of this study is to present a case of occipital artery to V3 segment vertebral artery bypass, emphasizing the role of quantitative magnetic resonance angiography (qMRA) in assessing flow and guiding surgical intervention. METHODS: A 66-year-old man with bilateral vertebral artery occlusion presented acute symptoms. qMRA was employed to evaluate flow dynamics and determine the feasibility of a flow augmentation bypass surgery. The occipital artery to left vertebral artery bypass (OA-to-VA) was performed, utilizing an inverted hockey-stick incision and an antegrade inside-out technique. The patency of the bypass was confirmed using both Doppler probe and Indocyanine green. RESULTS: Postoperative assessments, including computed tomography angiography (CTA) and qMRA, demonstrated the patency of the bypass with improved flow in the basilar artery and left vertebral artery. The patient's condition remained stable postoperatively, with residual peripheral palsy of the left facial nerve. CONCLUSION: In conclusion, the presented case illustrates the efficacy of the OA-to-VA bypass in addressing symptomatic bilateral vertebral artery occlusion. The study underscores the pivotal role of qMRA in pre- and postoperative assessments, providing noninvasive flow quantification for diagnostic considerations and long-term follow-up in patients with vertebrobasilar insufficiency.

In-stent restenosis after vertebral artery origin stenosis stenting: a nomogram for risk assessment.

OBJECTIVE: To propose a nomogram for individual risk assessment of in-stent restenosis (ISR) after vertebral artery origin stenosis (VAOS) stenting. METHODS: We included 793 patients with VAOS treated with stenting from October 2006 to May 2013, with a median follow-up of 27.8 months. Cox regression and the least absolute shrinkage and selection operator (LASSO) regression were adopted for variable selection. The nomogram was formulated and validated by concordance indexes (C-indexes) and calibration curves. An in-stent restenosis risk table (ISR-RT) was subsequently generated for risk stratification. Differences between low-, intermediate-, and high-risk levels were shown by Kaplan-Meier curves and compared by log-rank test. RESULTS: The training and validation set included 594 and 199 patients, with a mean ISR rate of 37.2% and 35.2%, respectively. Stent type (HR=1.64, 95% CI 1.26 to 2.14), stent diameter (HR=2.48, 95% CI 1.77 to 3.48), history of peripheral vascular disease (HR=2.17, 95% CI 1.17 to 4.00), history of transit ischemic attack (HR=1.45, 95% CI 1.05 to 2.14), and left-side involvement (HR=1.33, 95% CI 1.04 to 1.69) were included in the nomogram. The C-indexes at 6 and 12 months were 0.650 and 0.611 in the training set, and 0.713 and 0.603 in the validation set, respectively. Compared with low-risk patients, the intermediate- and high-level group had 1.46 (95% CI 1.05 to 2.04; p=0.0235) and 2.28 (95% CI 1.64 to 3.17; p<0.0001) higher chances of developing ISR in 2 years, respectively. CONCLUSIONS: A nomogram and a risk evaluation table were developed with good predictive ability for in-stent restenosis among patients with VAOS, which could serve as a practical approach for individualized risk evaluation.

Intracranial-Intracranial Bypass for Aneurysms: Quantitative Intraoperative Assessment of Flow Preservation.

BACKGROUND: Intraoperative flow measurement has proven utility in extracranial-intracranial bypass, particularly in assessing the adequacy of donors by measurement of cut flow. The nature of intracranial-intracranial (IC-IC) bypass precludes cut flow measurement, but quantitative intraoperative flow measurements may evaluate augment assessment of the bypass. OBJECTIVE: To retrospectively evaluate flow measurements performed in IC-IC bypass to determine the adequacy of the constructs in preserving flow. METHODS: With institutional review board approval, we performed a retrospective review of our bypass database from 2001 to 2021 for aneurysms treated with IC-IC bypass and with intraoperative flow measurements. Patients' preoperative characteristics, bypass indications, prebypass and postbypass intraoperative flow measurements, and patient outcomes were recorded. RESULTS: Of 346 bypasses, 21 cases using 22 IC-IC bypasses were included. The median age was 55 years; 13 of 21 cases were ruptured aneurysms. Aneurysms involved posterior inferior cerebellar artery (n = 7), middle cerebral artery (n = 6), distal anterior cerebral artery (n = 5), and anterior communicating artery (n = 3). Six bypasses were end-to-side (ETS), 10 were side-to-side (STS), and 6 were excisional with reanastomosis (end-to-end, ETE). Intraoperatively, 21 of the bypasses were patent; the postbypass/prebypass flow index averaged 1.15 (±0.32): ETE (n = 6) 1.22 ± 0.34 and ETS/STS bypasses (n = 15) 1.11 ± 0.32. All intraoperatively patent bypasses were patent on postoperative angiography. One occluded on delayed angiography without clinical sequelae. CONCLUSION: Despite advances in endovascular therapy, IC-IC bypass remains essential to the treatment of large and fusiform aneurysms. We demonstrate quantitatively that IC-IC donors provide adequate direct (ETE) and redistributed (STS ETS) flow to the recipient territory. Flow measurement provides valuable information regarding the patency and adequacy of IC-IC bypass for flow preservation.

Quantitative assessment of vertebral artery anatomy in relation to cervical pedicles: surgical considerations based on regional differences.

OBJECTIVE: To quantify the anatomic relationship between the Cervical pedicle screw (CPS), vertebral artery (VA), and related anatomic structures in the Saudi population. METHODS: This retrospective single center study included 50 consecutive patients (35 males) with normal neck findings on computed tomography angiography performed for trauma or vascular evaluation between 2012 and 2014. Radiologic parameters were assessed and correlated with age, weight, height, and body mass index (BMI). RESULTS: Mean age, weight, height, and BMI were 45.74+/-18.93 years, 79.72+/-21.80 kg, 164.74+/-11.53 cm, and 29.38+/-6.13 kg/m2, respectively. Mean cervical pedicle diameter (PD) increased from the cranial to caudal vertebrae (p=0.0001). Mean free zone (FZ) value, defined as the distance between the lateral CP border and medial VA border, was 1 mm (range 0.95-1.16 mm). The VA entry into the transverse foramina was at C6 level on both the right 92% and left side in most patients 94%. However, the right and left side level of VA entry differed in 14% of individuals. CONCLUSION: The PD and FZ are smaller in Saudi Arabians than in western populations. Assessment of VA entry at each level should be performed on an individual basis as the level of VA entry can differ in the same patient. Anatomic variations between different geographic areas should be studied to provide better surgical guidance.

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.

Vertebral artery-to-vertebral artery bypass with interposed radial artery or occipital artery grafts: surgical technique and report of three cases.

BACKGROUND: The treatment of unclippable vertebral artery (VA) aneurysms incorporating the posterior inferior cerebellar artery with parent artery preservation is among one of the most formidable challenges for cerebrovascular microsurgery and endovascular surgery. We propose that intracranial VA reconstruction using an extracranial VA-to-intracranial VA (VA-VA) bypass with a radial artery graft or an occipital artery graft may be an additional technique in the armamentarium to treat these formidable lesions. The rationale, surgical technique, and complications are discussed. METHODS: Three illustrative cases are described, in which the lesions were a VA dissecting aneurysm with ischemic lesions, bilateral asymptomatic unruptured VA aneurysms, and a VA giant aneurysm with subarachnoid hemorrhage. RESULTS: The partial extreme lateral infrajugular transcondylar approach was used. Computed tomographic angiography was useful for preoperative evaluation of the depth of the distal aneurysmal neck. A VA-VA bypass was performed in two patients. Because there was another ipsilateral aneurysm at the V2 segment in one patient, an external carotid artery-VA bypass was performed. Although two patients were discharged with good clinical results, one patient with subarachnoid hemorrhage died because of brainstem infarction. CONCLUSIONS: The VA-VA bypass using a radial artery graft or an occipital artery graft is an option that can be considered in the strategy for treating VA aneurysms to preserve the normal anatomic vascular configuration in the posterior circulation.

MicroNester coils as an adjunct to endovascular embolization.

OBJECTIVES/BACKGROUND: In June 2003, detachable balloons were removed from the US market and were supplanted with coil embolization for parent artery sacrifice in difficult or nonsurgical aneurysms and other vascular pathologies. The current series examines the use of MicroNester pushable coils (Cook Medical, Bloomington, IN) as a low-cost and effective adjunct to detachable coils in the treatment of selected neurovascular pathologies. METHODS: A retrospective analysis of all patients undergoing neurointerventional procedures from November 2003 through May 2008 was performed to identify patients in whom MicroNester coils were used as part of treatment. Analysis of coil type and number as well as pathology was performed. RESULTS: MicroNesters were used in 26 cases, of which 21 were for arterial sacrifice--19 for the internal carotid artery and 2 for the vertebral artery. Fourteen were performed for intracranial aneurysms, 3 for pseudoaneurysms, 2 for carotid cavernous fistulae, 1 for a carotid blowout, and 1 for an arteriovenous malformation. Five additional procedures were transvenous, for treatment of dural arterial venous fistulae. The mean number of coils for artery sacrifice was 13, with an average of 10 MicroNesters. For transvenous embolizations, the means were 30 and 6, respectively. CONCLUSION: MicroNesters are not the coil of choice for most neurointerventional procedures because they are not retrievable. However, when parent artery sacrifice or transvenous occlusion of dural arteriovenous fistulas is the goal, MicroNesters are a relatively inexpensive and equally effective alternative to more expensive, detachable coils and can reduce the procedural costs by $3600 to $6000 for the current series.

Assessment of vertebral artery stents using 16-slice multi-detector row CT angiography in vivo evaluation: comparison of a medium-smooth kernel and a sharp kernel.

OBJECTIVES: To assess the lumen visibility of extracranial vertebral artery stents examined with 16-slice multi-detector row computed tomography (MDCT) angiography in vivo using a medium-smooth kernel (B30s) and a sharp kernel (B60s), and to compare these with digital subtraction angiography (DSA) after stent placement. METHODS: Twenty stents from 20 patients (14 men, 6 women; mean age, 62.7+/-10.1 years) who underwent CT angiography (CTA) with 16-slice MDCT were retrospectively analyzed. In CT angiograms using a B30s and a B60s, the lumen diameters and CT attenuations of the stented vessels were measured three times by three observers, and artificial luminal narrowing (ALN) was calculated. To assess measurement reliability on CT angiograms, the intraclass correlation coefficient (ICC) was used. DSA served as the reference standard for the in-stent luminal measurements on CT angiography. The median interval between CT angiography and DSA was 1 day (range 1-10). RESULTS: For interobserver reliability, intraclass correlation coefficients for the lumen diameters on CT angiograms with a B30s and a B60s were 0.90 and 0.96, respectively. The lumen diameters on CT angiograms using a B30s were consistently smaller than that on CT angiograms using a B60s (p<0.01). The mean ALN was 37+/-7% on CT angiograms using a B30s and 25+/-9% on CT angiograms using a B60s. The mean CT attenuation in in-stent lumen was 347+/-55HU on CT angiograms using a B30s and 295+/-46HU on CT angiograms using a B60s. The ALN and CT attenuation within the stented vessels between CT angiograms using a B30s and a B60s was significant (p<0.01). CONCLUSIONS: 16-slice MDCT using a sharp kernel allows good visualization of the stented vessels and is useful in the assessment of vertebral artery stent patency after stent placement.

Simulation of cerebral hemodynamics for preoperative risk assessment.

BACKGROUND: An important part of the medical treatment of many cerebrovascular diseases is the occlusion of brain supplying arteries. Until now, the risk of this intervention can only be estimated by invasive diagnostics including the risk of cerebrovascular accidents. METHODS AND RESULTS: As a supporting tool, a computer model of the circle of Willis was designed. The model is based upon linear differential equations describing electrotechnical circuits extended non-linearly. By these means, time continuous simulations of different states and the online observation of all calculated state variables such as blood pressure and blood flow in every modeled vessel became feasible. For individual simulations, model parameters were determined by MR-angiography and boundary values by simultaneous Duplex-measurements in both carotid and vertebral arteries. State variables generated by the model behaved physiologically and the reaction of individual cerebrovascular systems in critical situations could be investigated by special scenarios. Inaccuracies concerning the determination of model parameters and boundary values of the used differential equations are likely to be resolved in the near future through a more careful and technically improved determination of these values. CONCLUSIONS: Computer models of subjects were created taking in account the individual anatomical and non-linear physical properties of real vascular systems supplying the brain. Thereby information could be obtained concerning the hemodynamic effects of an iatrogenic vascular occlusion.

Management-related morbidity and mortality in unselected aneurysms of the basilar trunk and vertebrobasilar junction.

OBJECTS: To analyze the management-related morbidity and mortality in unselected aneurysms of the basilar trunk and vertebrobasilar junction. The secondary objective was to investigate the factors associated with favourable or unfavourable surgical outcome in order to define subgroups for surgical and endovascular treatment. METHODS: 24 consecutive patients with aneurysms of the basilar trunk and vertebrobasilar junction were included in this study. They comprised 2.7% of all aneurysms treated during the study period between 1990 and 1997. 22 patients presented with acute subarachnoid hemorrhage (SAH) and 2 patients with symptoms of brainstem compresssion. All patients were managed using a standard protocol including surgery at the earliest possible moment, aggressive tripe-H therapy in patients with symptomatic vasospasm and mandatory follow-up angiography. 23 patients underwent surgical clipping and one patient endovascular coiling of the aneurysm. 12 patients had an excellent outcome. 6 patients had a good outcome, resulting in a total of satisfactory outcomes in 18 patients (75%). 4 patients (17%) had moderate to severe deficits. Two patients died (8%). Both patients had fusiform basilar trunk aneurysms. Good or excellent outcome was observed in 7 of 8 patients with aneurysms of the vertebrobasilar junction, 13 of 14 patients with moderate or minor SAH or without SAH (Fisher grade 0 to 2) and all patients with small sized aneurysm (n = 6). Factors mostly associated with poor outcome or death after surgical treatment were aneurysm location at the basilar trunk, large aneurysm size or fusiforme aneurysm type and severe SAH. CONCLUSIONS: Location, aneurysm size and the severity of SAH may help to predict the subgroup which highly benefits from surgical clipping of these rare vascular lesions.

Mandatory vs selective exploration for penetrating neck trauma. A prospective assessment.

To determine the optimal management of patients with penetrating wounds to zone II of the neck, we performed a prospective evaluation of 120 consecutive patients with such injuries, correlating the results of clinical and diagnostic examinations with operative findings. Seven patients presenting with life-threatening hemorrhage from the neck wound were operated on immediately; the remaining 113 patients underwent arteriography, laryngotracheoscopy, esophagoscopy, and esophagography, followed by neck exploration. Forty-eight major injuries were identified in 35 neck explorations. Five patients were identified with clinical and diagnostic findings that were considered normal preoperatively; however, at operation six major injuries were found in these patients. This study indicates that potentially lethal injuries to major vascular and visceral structures in the neck may go undetected if selective exploration criteria are used in the decision to explore penetrating wounds to zone II of the neck.

Medicare program; conditions for Medicare coverage of surgery to relieve obstructions to vertebral artery blood flow (vertebral artery surgery)--Health Care financing Administration. Notice of HCFA ruling.

This notice announces a HCFA ruling that restates Medicare policy on coverage of vertebral artery surgery. Medicare covers medical procedures only if the procedures are safe and effective. Available evidence shows that five types of surgical procedures performed to relieve an obstruction of the vertebral artery blood flow are safe and effective, but only if each of four conditions is met.