Dr. Andrew  Ringer  Md image

Dr. Andrew Ringer Md

222 Piedmont Ave Third Floor, Suite 3100
Cincinnati OH 45219
513 211-1100
Medical School: Other - Unknown
Accepts Medicare: No
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License #: 35079482
NPI: 1134237712
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Measuring outcomes for neurosurgical procedures. - Neurosurgery clinics of North America
Health care evolution has led to focused attention on clinical outcomes of care. Surgical disciplines are increasingly asked to provide evidence of treatment efficacy. As the technological advances push the surgical envelope further, it becomes imperative that postoperative outcomes are studied in a prospective fashion to assess the quality of care provided. The authors present their experience from a multiyear implementation of an outcomes initiative and share lessons learned, emphasizing the important structural elements of such an endeavor.Copyright © 2015 Elsevier Inc. All rights reserved.
Changes in computed tomography perfusion parameters after superficial temporal artery to middle cerebral artery bypass: an analysis of 29 cases. - Journal of neurological surgery. Part B, Skull base
Introduction Analysis of computed tomography perfusion (CTP) studies before and after superficial temporal artery to middle cerebral artery (STA-MCA) bypass is warranted to better understand cerebral steno-occlusive pathology. Methods Retrospective review was performed of STA-MCA bypass patients with steno-occlusive disease with CTP before and after surgery. CTP parameters were evaluated for change after STA-MCA bypass. Results A total of 29 hemispheres were bypassed in 23 patients. After STA-MCA bypass, mean transit time (MTT) and time to peak (TTP) improved. When analyzed as a ratio to the contralateral hemisphere, MTT, TTP, and cerebral blood flow (CBF) improved. There was no effect of gender, double vessel versus single vessel bypass, or time until postoperative CTP study to changes in CTP parameters after bypass. Conclusions Blood flow augmentation after STA-MCA bypass may best be assessed by CTP using baseline MTT or TTP and ratios of MTT, TTP, or CBF to the contralateral hemisphere. The failure of cerebrovascular reserve to improve after cerebral bypass may indicate irreversible loss of autoregulation with chronic cerebral vasodilation or the inability of CTP to detect these improvements.
Early reperfusion and clinical outcomes in patients with M2 occlusion: pooled analysis of the PROACT II, IMS, and IMS II studies. - Journal of neurosurgery
The role of endovascular therapy in patients with acute ischemic stroke and a solitary M2 occlusion remains unclear. Through a pooled analysis of 3 interventional stroke trials, the authors sought to analyze the impact of successful early reperfusion of M2 occlusions on patient outcome.Patients with a solitary M2 occlusion were identified from the Prolyse in Acute Cerebral Thromboembolism (PROACT) II, Interventional Management of Stroke (IMS), and IMS II trial databases and were divided into 2 groups: successful reperfusion (thrombolysis in cerebral infarction [TICI] 2-3) at 2 hours and failed reperfusion (TICI 0-1) at 2 hours. Baseline characteristics and clinical outcomes were compared.Sixty-three patients, 40 from PROACT II and 23 from IMS and IMS II, were identified. Successful early angiographic reperfusion (TICI 2-3) was observed in 31 patients (49.2%). No statistically significant difference in the rates of intracerebral hemorrhage (60.9% vs 47.6%, p = 0.55) or mortality (19.4% vs 15.6%, p = 0.75) was observed. However, there was a trend toward higher incidence of symptomatic hemorrhage in the TICI 2-3 group (17.4% vs 0%, p = 0.11). There was also a trend toward higher baseline glucose levels in this group (151.5 mg/dl vs 129.6 mg/ dl, p = 0.09). Despite these differences, the rate of functional independence (modified Rankin Scale Score 0-2) at 3 months was similar (TICI 2-3, 58.1% vs TICI 0-1, 53.1%; p = 0.80).A positive correlation between successful early reperfusion and clinical outcome could not be demonstrated for patients with M2 occlusion. Irrespective of reperfusion status, such patients have better outcomes than those with more proximal occlusions, with more than 50% achieving functional independence at 3 months.
Utilization of Pipeline embolization device for treatment of ruptured intracranial aneurysms: US multicenter experience. - Journal of neurointerventional surgery
Utilization of the Pipeline embolization device (PED) in complex ruptured aneurysms has not been well studied. We evaluated the safety and effectiveness data from five participating US centers.Records of patients with ruptured cerebral aneurysms who underwent PED treatment between 2011 and 2013 were retrospectively reviewed.26 patients with ruptured aneurysms underwent PED treatment (mean age 51.4±13.2 years;16 women). At presentation, 8 patients (30.8%) had a Hunt-Hess grade of IV or above; 11 required extraventricular drain placement. Aneurysm morphologies were: 8 dissecting, 8 blister-like, 6 fusiform, and 4 saccular. There were 22 anterior circulation and 4 posterior circulation aneurysms. PED deployment was successful in all patients, with adjunctive coiling utilized in 12. Periprocedural complications occurred in 5 (19.2%), including 3 inhospital deaths. 23 patients (88.5%) had postoperative angiography at a mean of 5.9 months: 18 aneurysms (78.3%) were completely occluded, 3 (13.0%) had residual neck filling, and 2 (8.7%) had residual dome filling. All blister-type aneurysms were completely occluded at follow-up. Clinical follow-up was available for an average of 10.1 months (range 2-21 months), with one asymptomatic in-stent stenosis and one asymptomatic thromboembolic stroke noted. Good outcome (modified Rankin Scale (mRS) score of 0-2) was achieved in 20 patients (76.9%), fair (mRS 3-4) in 3 (11.5%), and 3 died (11.5%).The PED can be utilized for ruptured aneurysms and is a good option for blister-type aneurysms. However, due to periprocedural complications, it should be reserved for lesions that are difficult to treat by conventional clipping or coiling.Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to
Geographic access to acute stroke care in the United States. - Stroke; a journal of cerebral circulation
Only 3% to 5% of patients with acute ischemic stroke receive intravenous recombinant tissue-type plasminogen activator (r-tPA) and <1% receive endovascular therapy. We describe access of the US population to all facilities that actually provide intravenous r-tPA or endovascular therapy for acute ischemic stroke.We used US demographic data and intravenous r-tPA and endovascular therapy rates in the 2011 US Medicare Provider and Analysis Review data set. International Classification of Diseases-Ninth Revision codes 433.xx, 434.xx and 436 identified acute ischemic stroke cases. International Classification of Diseases-Ninth Revision code 99.10 defined intravenous r-tPA treatment and International Classification of Diseases-Ninth Revision code 39.74 defined endovascular therapy. We estimated ambulance response times using arc-Geographic Information System's network analyst and helicopter transport times using validated models. Population access to care was determined by summing the population contained within travel sheds that could reach capable hospitals within 60 and 120 minutes.Of 370,351 acute ischemic stroke primary diagnosis discharges, 14,926 (4%) received intravenous r-tPA and 1889 (0.5%) had endovascular therapy. By ground, 81% of the US population had access to intravenous-capable hospitals within 60 minutes and 56% had access to endovascular-capable hospitals. By air, 97% had access to intravenous-capable hospitals within 60 minutes and 85% had access to endovascular hospitals. Within 120 minutes, 99% of the population had access to both intravenous and endovascular hospitals.More than half of the US population has geographic access to hospitals that actually deliver acute stroke care but treatment rates remain low. These data provide a national perspective on acute stroke care and should inform the planning and optimization of stroke systems in the United States.© 2014 American Heart Association, Inc.
Life-threatening allergic vasculitis after clipping an unruptured aneurysm: Case report, weighing the risk of nickel allergy. - Surgical neurology international
This case report represents one of the estimated 17,000 aneurysms clipped annually in the United States, often with nickel-containing clips. The authors highlight the development of life-threatening allergic vasculitis in a 33-year-old woman after aneurysm clipping.After suffering subarachnoid hemorrhage, the patient had coil embolization at another facility for rupture of a right internal carotid artery (ICA) aneurysm. An incidental finding, an unruptured left posterior communicating artery aneurysm unamenable to coiling, was then successfully clipped via a left pterional craniotomy. Arriving in our emergency department 11 days later, she progressively declined during the next weeks, facing deteriorating clinical status (i.e. seizures) and additional infarctions in the left frontal lobe, midline shift, and new infarctions in the bilateral frontal lobe, right sylvian, right insular regions, and posterior cerebral artery distribution. During decompressive surgery, biopsy findings raised the possibility of lymphocytic vasculitis; consultations with rheumatology, allergy, and immunology specialists identified that our patient had a nickel allergy. After reoperation to replace the nickel-containing clip with one of a titanium alloy, the patient had an uncomplicated postoperative course and was discharged 6 days later to a rehabilitation facility.Nickel-related allergies are more common than appreciated, affecting up to 10% of patients. Fortunately, severe reactions are rare; nevertheless, vascular neurosurgeons should be aware of this potential complication when using cobalt alloy aneurysms clips. The use of titanium alloy clips eliminates this risk.
Vertebrobasilar fusiform aneurysms. - Neurosurgery clinics of North America
Unlike saccular or berry aneurysms, which present more often with subarachnoid hemorrhage, fusiform aneurysms present more often with ischemic stroke or mass effect. The most time-tested treatment of fusiform vertebrobasilar aneurysms consists of flow reduction or flow reversal. Recently, flow diversion has been attempted with mixed results in the posterior circulation. Given the described pathophysiologic processes of fusiform aneurysms that may be altered with modern medical therapies, future investigators may look to medical treatment of these lesions, especially in cases of poor surgical candidates.Copyright © 2014 Elsevier Inc. All rights reserved.
Feasibility and safety of pipeline embolization device in patients with ruptured carotid blister aneurysms. - Neurosurgery
Treatment of internal carotid ruptured blister aneurysms (IC-RBA) presents many challenges to neurosurgeons because of the high propensity for rebleeding during intervention. The role of a Pipeline Embolization Device (PED) in the treatment of this challenging aneurysm subtype remains undefined despite theoretical advantages.To present a series of 11 patients treated with a PED and to discuss the management and results of this novel application of flow diverters.Medical records of patients who presented with IC-RBA from May 2011 to March 2013 were retrospectively reviewed at 6 institutions in the United States. All relevant data were independently compiled.A total of 12 IC-RBAs in 11 patients were treated during the study period. Nine (75%) were treated with a single PED; 1 was treated with 2 PEDs; 1 was treated with coils and 1 PED; and 1 was treated with coils and 2 PEDs. Three (27%) had major perioperative complications: middle cerebral artery territory infarction, vision loss, and death. Seven patients demonstrated complete obliteration of the aneurysm in postoperative imaging. Early clinical outcomes were favorable (modified Rankin Scale score, 0-2) in all 10 survivors.This study demonstrates the feasibility and safety of using the PED to treat IC-RBA with fair initial results. The proper introduction and management of antiplatelet regimen are key for successful results. Bleeding complications related to dual antiplatelet therapy were similar to those in previous studies of stent-assisted coiling for the same population. Larger cohort analysis is needed to define the precise role of flow diverters in the treatment of IC-RBA.
Onyx HD-500 embolization of intracranial aneurysms: modified technique using continuous balloon inflation under conscious sedation. - Journal of clinical neuroscience : official journal of the Neurosurgical Society of Australasia
The conventional technique of intracranial aneurysm embolization using Onyx HD-500 (ev3 Neurovascular, Irvine, CA, USA) involves repetitive balloon inflation-deflation cycles under general anesthesia. By limiting parent artery occlusion to 5 minutes, this cyclic technique is thought to minimize cerebral ischemia. However, intermittent balloon deflation may lengthen procedure time and allow balloon migration, resulting in intimal injury or Onyx leakage. We report our experience using a modified technique of uninterrupted Onyx injection with continuous balloon occlusion under conscious sedation. All Onyx embolization procedures for unruptured aneurysms performed by the senior author (A.J.R.) between September 2008 and April 2010 were retrospectively reviewed. Demographic, clinical, angiographic, and procedural data were recorded. Twenty-four embolization procedures were performed in 21 patients with 23 aneurysms, including four recurrences. Twenty aneurysms (87%) involved the paraclinoid or proximal supraclinoid internal carotid artery. Size ranged from 2.5 to 24mm and neck diameter from 2 to 8mm. The modified technique was employed in 19 cases. All but one patient (94.4%) tolerated continuous balloon inflation. Complete occlusion was achieved in 20 aneurysms (83.3%) and subtotal occlusion in three (12.5%). Stable angiographic results were seen in 85%, 94%, 94%, and 100% of patients at 6, 12, 24, and 36months, respectively. There were no deaths. Permanent non-disabling neurological morbidity occurred in one patient (4.2%). Minor, transient, and/or angiographic complications were seen in three patients (12.5%), none related to the technique itself. Onyx embolization of unruptured intracranial aneurysms can be safely and effectively performed using continuous balloon inflation under conscious sedation.Copyright © 2014 Elsevier Ltd. All rights reserved.
Predicting parent vessel patency and treatment durability: a proposed grading scheme for the immediate angiographic results following Onyx HD-500 embolization of intracranial aneurysms. - Journal of neurointerventional surgery
Onyx HD-500 embolization of intracranial aneurysms leads to high rates of complete and durable occlusion. However, little information exists as to what constitutes an optimal immediate angiographic result. We devised a simple grading scheme based on the pattern of parent artery and aneurysm neck reconstruction, and correlated it with long term outcome.All cases of Onyx embolization for unruptured aneurysms performed between September 2008 and April 2010 were retrospectively reviewed. Immediate angiographic results were categorized according to the pattern of extra-aneurysmal Onyx leakage: grade A, none; grade B, 'hat brim' lamination; and grade C, 'ectopic' Onyx (C1, non-flow limiting; C2, flow limiting). Results of follow-up vascular imaging were reviewed and correlated with the angiographic grade.24 embolization procedures were performed in 21 patients with 23 aneurysms. Aneurysm size ranged from 2.5 to 24 mm and neck width from 2 to 8 mm. Complete occlusion was achieved in 20 cases (83.3%) and subtotal occlusion in three (12.5%). Immediate angiographic results were: grade A in ten (41.7%), grade B in eight (33.3%), and grade C in six (25%). Stable angiographic results were seen in 85%, 94%, 94%, and 100% at 6, 12, 24, and 36 months, respectively. Angiographic recurrence was observed in four cases (16.7%), all grade A (p=0.006). Delayed parent vessel occlusion occurred in two cases (8.3%), both grade C2 (p=0.014).This simple grading system may help predict long term angiographic results. Hat brim Onyx lamination seems to provide an optimal balance between treatment durability and parent vessel patency. Prospective validation is warranted.Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to

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