Intra-arterial Thrombolysis for Acute Ischemic Stroke: Preliminary Experience with Platelet Glycoprotein IIb/IIIa Inhibitors as Adjunctive Therapy

Platelet Glycoprotein IIb/IIIa Receptor Inhibitor Tirofiban in Acute Ischemic Stroke

Tirofiban is a non-peptide selective glycoprotein (GP) IIb/IIIa receptor inhibitor that reversibly inhibits fibrinogen-dependent platelet aggregation and subsequent formation of thrombi, which contribute to the major atherosclerotic complications in the development, progression, and resolution of ischemic stroke. The adjunctive use of tirofiban has been extensively evaluated in progressive stroke, combined intravenous thrombolysis (IVT), and endovascular treatment (EVT) in both preclinical and clinical studies. A body of evidence has been accumulated on the risks and benefits associated with tirofiban in terms of prevention of stroke progression, stent thrombosis, improvement in functional independence, and mortality, especially among high-risk ischemic stroke patients as a further strategy alongside conventional treatment. In general, tirofiban has a favorable tolerability and efficacy profile in the improvement of vascular recanalization and long-term functional outcome, although the optimum dosage, application setting, and precise target patients are not yet well-established. However, its specific inhibition of ongoing platelet aggregation and thrombus formation rather than absolute thrombolysis suggests that tirofiban, one of the most widely used GP IIb/IIIa inhibitors, with high affinity and a short plasma/biologic half-life, may have great potential in the acute treatment of ischemic stroke. Substantial practical progress is likely as our understanding of the mechanism of action and pharmacological actions of tirofiban in atherosclerotic ischemic disease improves. Therefore, we classify and summarize the available findings regarding tirofiban in acute ischemic stroke to stimulate and guide further research and clinical practice.

What is meant by "TICI"?

BACKGROUND

In 2003, Higashida et al proposed the Thrombolysis In Cerebral Infarction scale to evaluate angiographic intracranial flow. Our aim is to review how subsequently published studies define TICI.

MATERIALS AND METHODS

We used the ISI Web of Knowledge and SciVerse Scopus databases to search for "TICI" and "thrombolysis in cerebral infarction" and for articles that cited the original TICI paper from January 2004 through May 2012. Articles were categorized according to their definition of the TICI categories, typically grades 0-4, with grade 2 (partial reperfusion) subdivided into 2a and 2b, and rate of contrast entry to the perfused area. In addition, we catalogued the type of redefinitions of TICI subcategory 2 and additions of new categories.

RESULTS

Of 236 articles screened, 74 were included. Eight (11%) explicitly followed the TICI scale as originally defined. Thirty-seven (50%) cited Higashida but did not define their scale. Fifteen (21%) used and explained modified scales. Thirteen (18%) used the term TICI, but did not define the scale and did not cite Higashida. Eighteen (24%) specified a 2a subcategory. Nine defined grade 2a as <67% filling, 6 defined it as <50%, and 3 did not offer a percentage. Two studies added a 2c subcategory. Fifty-two (70%) used a cutoff level to define "successful reperfusion." Of these, 65% used TICI ≥2, 33% used TICI ≥2b, and 2% used TICI = 3.

CONCLUSIONS

There is substantial variability in the definition and/or application of the TICI scale in the literature. This variability could considerably impact our understanding of results of revascularization studies.

Guidelines for the early management of patients with acute ischemic stroke: a guideline for healthcare professionals from the American Heart Association/American Stroke Association

BACKGROUND AND PURPOSE

The authors present an overview of the current evidence and management recommendations for evaluation and treatment of adults with acute ischemic stroke. The intended audiences are prehospital care providers, physicians, allied health professionals, and hospital administrators responsible for the care of acute ischemic stroke patients within the first 48 hours from stroke onset. These guidelines supersede the prior 2007 guidelines and 2009 updates.

METHODS

Members of the writing committee were appointed by the American Stroke Association Stroke Council's Scientific Statement Oversight Committee, representing various areas of medical expertise. Strict adherence to the American Heart Association conflict of interest policy was maintained throughout the consensus process. Panel members were assigned topics relevant to their areas of expertise, reviewed the stroke literature with emphasis on publications since the prior guidelines, and drafted recommendations in accordance with the American Heart Association Stroke Council's Level of Evidence grading algorithm.

RESULTS

The goal of these guidelines is to limit the morbidity and mortality associated with stroke. The guidelines support the overarching concept of stroke systems of care and detail aspects of stroke care from patient recognition; emergency medical services activation, transport, and triage; through the initial hours in the emergency department and stroke unit. The guideline discusses early stroke evaluation and general medical care, as well as ischemic stroke, specific interventions such as reperfusion strategies, and general physiological optimization for cerebral resuscitation.

CONCLUSIONS

Because many of the recommendations are based on limited data, additional research on treatment of acute ischemic stroke remains urgently needed.

Intra-arterial tirofiban infusion for partial recanalization with stagnant flow in hyperacute cerebral ischemic stroke

Early reocclusion is a major concern associated with poor clinical outcomes in patients with an ischemic cerebral stroke. This occurs most frequently in patients with partial initial recanalization. This study focuses on partial recanalization with stagnant antegrade flow after intravenous (IV) tPA or spontaneously, treated with the administration of intra-arterial (IA) tirofiban. Three patients with initial M1 occlusion on diagnostic studies had an occluded segment that was recanalized with stagnant flow after IV tPA or spontaneously. In all cases, IA tirofiban was administrated. We evaluated the distal blood flow and the degree of vascular narrowing in the pre and post-procedure angiography and at follow-up in addition to the clinical status. In all patients, severe vascular narrowing with stagnation of blood flow was detected in the initial M1. After infusion of IA tirofiban, improvement of the distal blood flow was achieved rapidly within 40 minutes in all patients. The severe vascular narrowing resolved rapidly in two patients without residual stenosis. In one patient, moderate vascular narrowing was still present. The median baseline National Institutes of Health Stroke Scale (NIHSS) scores were 18 and the median post-procedural NIHSS scores were 2 at two weeks. No intracerebral hemorrhage occurred in any of the patients. Treatment with IA tirofiban was safe and effective in patients with partial initial recanalization. It can be suggested that detection of any partial recanalization is time for administration of glycoprotein IIb-IIIa receptor inhibitor in hyperacute ischemic stroke.

Impact of tissue plasminogen activator on the neurovascular unit: from clinical data to experimental evidence

About 15 million strokes occur each year worldwide. As the number one cause of morbidity and acquired disability, stroke is a major drain on public health-care funding, due to long hospital stays followed by ongoing support in the community or nursing-home care. Although during the last 10 years we have witnessed a remarkable progress in the understanding of the pathophysiology of ischemic stroke, reperfusion induced by recombinant tissue-type plasminogen activator (tPA-Actilyse) remains the only approved acute treatment by the health authorities. The objective of the present review is to provide an overview of our present knowledge about the impact of tPA on the neurovascular unit during acute ischemic stroke.

Intra-arterial adjuvant tirofiban after unsuccessful intra-arterial thrombolysis of acute ischemic stroke: preliminary experience in 16 patients

INTRODUCTION

Intra-arterial (IA) thrombolysis with plasminogen activator is well-known, but the use of IA tirofiban as an adjuvant for IA thrombolysis is not well-known. We investigated the feasibility of IA tirofiban as an adjuvant after unsuccessful IA recanalization with urokinase (UK) for acute ischemic stroke.

METHODS

We retrospectively analyzed all 16 consecutive patients (11 men and five women; mean age, 61.3 years; range, 36-85 years) who were treated with IA tirofiban after isolated IA thrombolysis with UK or bridging therapy with systemic recombinant tissue plasminogen activator (rt-PA; 0.6 mg/Kg) and IA UK for acute ischemic stroke. Outcome measures included angiographic recanalization (thrombolysis in cerebral infarction, TICI), symptomatic and asymptomatic intracerebral hemorrhage (ICH), mortality, and functional independence at 3 months (modified Rankin Scale, 0-2).

RESULTS

Among the 16 patients treated with IA tirofiban as an adjuvant, 10 patients had conventional dose (<25 ug/kg, bolus) and six patients had high dose (≥25 ug/kg, bolus) of IA tirofiban after unsuccessful IA thrombolysis whether systemic rt-PA used or not. Successful angiographic recanalization (TICI grade 2b or 3) was achieved in 13 patients (13/16) and a functional independence at 3 months in eight patients (8/16). Three months after therapy, three patients had died. There were two patients of symptomatic ICH and four asymptomatic ICH.

CONCLUSION

Conventional dose of IA tirofiban as an adjuvant during IA thrombolysis for acute ischemic stroke seems feasible. However, further dose escalation studies should be performed regarding the IA use of tirofiban for acute ischemic stroke.

Intra-arterial therapy for acute ischemic stroke

Intra-arterial therapy (IAT) for acute ischemic stroke refers to endovascular catheter-based approaches to achieve recanalization using mechanical clot disruption, locally injected thrombolytic agents or both. IAT may be used in addition to intravenous tissue plasminogen activator (tPA) or in patients who do not qualify for tPA, usually because they are outside the approved 3-h timeframe window or have contraindications, such as elevated international normalized ratio or partial thromboplastin time. Recanalization rates correlate with clinical improvement, and with the newest catheters it is possible to achieve recanalization in roughly 80% of patients treated. However, while the catheters are approved by the Food and Drug Administration, there are still no randomized trial data demonstrating the role of current IAT therapy vs either tPA or standard management. IAT is reserved for patients with large artery occlusions in the basilar, distal carotid, or proximal middle cerebral arteries. Imaging the penumbra using magnetic resonance imaging or computed tomographic perfusion is currently the most frequently used way to identify patients who might benefit. However, the imaging and clinical criteria for identifying which patients benefit, and perhaps more importantly those who will do poorly despite IAT, remain unclear.

Safety and feasibility of intraarterial eptifibatide as a revascularization tool in acute ischemic stroke

OBJECT

Experience with the use of platelet glycoprotein (GP) IIb-IIIa inhibitor eptifibatide in patients with ischemic stroke is limited. The authors report the off-label use of intraarterial eptifibatide during endovascular ischemic stroke revascularization procedures for reocclusion after documented recanalization or formed fresh thrombi in distal vessels that were inaccessible to endovascular devices.

METHODS

Patients who received intraarterial eptifibatide were identified from a prospectively collected database of patients in whom endovascular revascularization for acute ischemic stroke was attempted between 2005 and 2008. Data were analyzed retrospectively. The intraarterial eptifibatide dose was a single-bolus dose of 180 μg/kg body weight. Primary outcome measures were angiographic recanalization (Thrombolysis in Myocardial Infarction Grade 2 or 3), symptomatic intracranial hemorrhage rate, overall mortality rate, and favorable 3-month modified Rankin Scale score (≤ 2).

RESULTS

The study included 35 patients (mean age 62 years, range 18-85 years). The median presenting National Institutes of Health Stroke Scale score was 13. Two patients received intravenous tissue plasminogen activator before endovascular therapy. The median time from symptom onset to therapy initiation was 230 minutes (range 90-1370 minutes). Twelve patients (34%) received intraarterial tissue plasminogen activator without mechanical measures. Mechanical revascularization measures used were Merci retriever in 19 (54%), Penumbra device in 1 (3%), balloon angioplasty in 15 (43%), and stent placement in 22 (63%) patients. The mean dose of intraarterial eptifibatide was 11.6 mg (range 5-16.6 mg). Partial-to-complete recanalization (Thrombolysis in Myocardial Infarction Grade 2 or 3) was achieved in 27 patients (77%). Postprocedure intracranial hemorrhage occurred in 13 patients (37%), causing symptoms in 5 (14%). In the 5 symptomatic intracranial hemorrhage cases, all patients but one presented more than 8 hours after symptom onset and all received intraarterial recombinant tissue plasminogen activator. The median discharge National Institutes of Health Stroke Scale score was 7 (range 0-17). At 3 months postprocedure, 21 patients (60%) had a modified Rankin Scale score ≤ 2, and 8 patients (23%) had died.

CONCLUSIONS

Adjunctive intraarterial eptifibatide is a feasible option for salvage of reocclusion and thrombolysis of distal inaccessible thrombi during endovascular stroke revascularization. Its safety and efficacy need to be studied further in larger, multicenter, controlled studies.

Safety and Effectiveness of Endovascular Therapy After 8 Hours of Acute Ischemic Stroke Onset and Wake-Up Strokes

Background and Purpose— This is a retrospective review of patients who underwent endovascular recanalization ≥8 hours after acute ischemic stroke symptom onset, including wake-up strokes, between June 2005 and June 2008.

Methods— Thirty patients with a premorbid modified Rankin score ≤1 and NIHSS between 5 and 22 were included. All had admission CT, CTA, and CT perfusion scans to evaluate for salvageable brain tissue. Recanalization effectiveness was assessed by angiograms obtained within 30 hours after intervention. Patient, treatment characteristics, and immediate and 3-month outcomes were analyzed.

Results— Mean NIHSS at presentation was 13 (median=12). Mean interval between time last-seen well and angiogram was 12.75 hours (median=10). Twenty-six patients (86.7%) presented with complete-to-near-complete vessel occlusion (thrombolysis in myocardial infarction [TIMI] 0/1); 4 had partial vessel occlusion (TIMI 2). Interventions included intra-arterial pharmacological thrombolysis (n=10), mechanical thrombectomy(n=21; Merci, 16; intracranial stent, 9; extracranial stent, 3), angioplasty (n=14; intracranial, 11; extracranial, 3). Nine patients received GPIIb/IIIa inhibitors (eptifibatide); all received heparin. Partial-to-complete recanalization (TIMI 2/3) was achieved in 20 patients (66.7%). Procedure-related complications included vascular perforations (n=3) and femoral access site complication (n=1). One patient had an embolic anterior cerebral artery infarct during intervention; another had progression of brain stem infarct. Symptomatic intracerebral hemorrhage occurred in 3 patients (10%), with 2 being primarily subarachnoid in location. Total in-hospital mortality including procedural mortality, disease progression, or other comorbidities was 23.3% (n=7). Mean discharge NIHSS was 9.5, representing an overall NIHSS 3.5-point improvement. Overall, mean modified Rankin score at death or last follow-up (mean=10.6 months) was 4.2. At 3 months, total mortality was 33.3% (n=10), 20% had modified Rankin score ≤2, and 33% had modified Rankin score ≤3. Among survivors, mean modified Rankin score at 3-month follow-up was 3.

Conclusion— Our data show that delayed endovascular revascularization of carefully selected patients is safe, effective, and improves clinical outcome.

Endovascular approaches to acute stroke, part 1: Drugs, devices, and data

Despite years of research and pioneering clinical work, stroke remains a massive public health concern. Since 1996, we have lived in the era of US Food and Drug Administration-approved intravenous (i.v.) recombinant tissue plasminogen activator (rtPA). This treatment, despite its promise, continues to exhibit its limitations. Endovascular therapy has several theoretic advantages over i.v. rtPA, including site specificity, longer treatment windows, and higher recanalization rates. In this article, we will review the various pharmacologic strategies for acute stroke treatment, providing both a historic context and the state of the art. The drugs will be classified on the basis of their theoretic rationale for therapy. Next, we will review the various devices and strategies for mechanical revascularization with an aim toward comprehensiveness. These range from wire disruption of thrombus to preclinical trials for novel mechanical solutions. This first installment of this 2-part series will end with an analysis of retrograde reperfusion techniques.

The plastic surgeon's role in extracranial-to-intracranial bypass using a reverse great saphenous vein graft

BACKGROUND

Extracranial-to-intracranial bypass is used for flow replacement and diversion that prevent the serious complications associated with sudden ligation of the middle cerebral artery for treatment of complex tumors or aneurysms. Extracranial-to-intracranial bypass is a demanding procedure that requires experience in advanced microsurgical techniques. In this article, the authors review the first report of an extracranial-to-intracranial bypass performed by a plastic surgeon with emphasis on indications for microsurgical involvement in neurosurgical practice and on description of the surgical technique.

METHODS

Between April of 2004 and October of 2006, three extracranial-to-intracranial bypass cases were performed including one for a complex aneurysm rupture and two for resections of cranial base tumors. In every case, the intracranial approach was used by the neurosurgeon. The bypass was performed by interposing a reverse great saphenous vein graft between the superficial temporal artery, in end-to-end anastomosis, and the second segment of the middle cerebral artery, in end-to-side anastomosis.

RESULTS

In each case, postoperative cerebral angiography demonstrated complete patency of the extracranial-to-intracranial bypass. Neither of the two surviving patients at a mean follow-up of 13 months had deterioration of neurologic function, postoperative stroke, or surgery-related death. One of the patients was dead before the 6-month follow-up.

CONCLUSIONS

The reverse great saphenous vein graft is a good option for extracranial-to-intracranial bypass, with the advantages of high-flow graft, wide lumen, adequate length, easy harvest, and minimal donor-site morbidity. The plastic surgery/neurosurgery alliance allows scope for improved outcomes in complex neurosurgical cases and continues to push the frontiers of reconstructive microsurgery.

Combination pharmacotherapy for achievement and maintenance of vascular patency

Acute ischemic stroke results from an abrupt interruption of focal cerebral blood flow. In the majority of cases, this interruption is caused by an acute thromboembolism. Arising from the clinical trials in acute myocardial infarction, combination pharmacotherapy is gaining significant interest as a potential method to improve current thrombolytic treatment in acute ischemic stroke. This article reviews the scientific rationale and available evidence for the potential options to improve current pharmacologic therapy for achieving and maintaining vascular patency in acute ischemic stroke.

Double-balloon trapping technique for embolization of a large wide-necked superior cerebellar artery aneurysm: case report

OBJECTIVE

To describe a novel double-balloon trapping technique for endovascular embolization of a broad-based saccular aneurysm of the superior cerebellar artery.

CLINICAL PRESENTATION

A 62-year-old man with a history of diabetes, coronary artery disease, and smoking presented with a syncopal episode. Catheter angiography revealed a large (11.7 x 9.4 x 11.2 mm) right superior cerebellar artery (SCA) aneurysm with a 7-mm neck, incorporating the origin of the right SCA.

INTERVENTION

An endovascular double-balloon trapping technique was used. Using bilateral groin access and bilateral vertebral artery guide catheters, a 4 x 20 mm HyperGlide balloon (ev3 Neurovascular, Irvine, CA) was placed across the neck of the aneurysm, and a 4 x 7 mm HyperForm balloon (ev3 Endovascular Inc., Plymouth, MN) was placed within the aneurysm. The aneurysm was catheterized with an Echelon 14 microcatheter (ev3 Endovascular Inc.). The inflated HyperGlide balloon was used to protect the parent basilar artery and "trap" the smaller HyperForm balloon within the aneurysm. The HyperForm balloon was inflated within the aneurysm and gently retracted to protect the origin of the SCA at the aneurysm neck. The aneurysm was coiled with the balloons inflated. A 4.5 x 20 mm Neuroform stent (Boston Scientific, Natick, MA) was deployed across the aneurysm neck. Final procedural angiography showed near complete occlusion of the aneurysm and preservation of flow in the SCA. Follow-up angiography at 8 months showed progressive thrombosis with complete occlusion of the aneurysm, preserved patency of the SCA, and anatomic reconstruction of the native artery. The patient remained neurologically normal at the time of the follow-up evaluation.

CONCLUSION

Double-balloon trapping is a novel endovascular technique that can be used to treat wide-necked aneurysms and maintain patency of side branches incorporated into the aneurysm neck.

Implications of lumbar plexus anatomy for removal of total disc replacements through a posterior approach

STUDY DESIGN

An anatomic study in which the lumbar plexuses of 14 embalmed cadavers were dissected bilaterally and measured using a posterior approach.

OBJECTIVE

To determine the cephalocaudal (root-to-root) distances and the mediolateral (root-to-tether) distances within the lumbar plexus and determine the feasibility for removal of a lumbar total disc replacement (TDR) through these anatomic spaces using a posterior approach.

SUMMARY OF BACKGROUND DATA

Currently, lumbar TDRs are implanted primarily through an anterior retroperitoneal or transperitoneal approach. However, revision surgeries through these approaches can be complicated by significant adhesions, with potential injuries to intra- and retroperitoneal contents. Advancements in accessing anterior column structures through a posterior lumbar extracavitary approach suggest that posterior removal of TDRs may be an alternative. Unlike the thoracic extracavitary approach in which ligation of the thoracic nerve rarely leaves significant morbidity, the lumbar extracavitary approach cannot rely on the analogous ligation of the lumbar root to achieve access. Therefore, feasibility of the lumbar extracavitary approach depends on the presence of sufficient anatomic space between the tethered nerves of the lumbar plexus.

METHODS

Fourteen adult cadavers (5 M/9F) were dissected through a posterior approach to expose the lumbar plexus bilaterally. The root-to-root distances at levels L2-S1 and corresponding root-to-tether distances at levels L3-L5 were measured bilaterally.

RESULTS

Root-to-root distance was smallest at the male L5-S1 interval (11.7 +/- standard deviations 4.1 mm). Root-to-tether distance was smallest at the female L5 (43.1 +/- standard deviations 8.4 mm). These plexus measurements compare favorably with the CHARITE TDR components, in which the thickest sliding core is 11.0 mm in height and the largest endplate is 42.0 mm in width.

CONCLUSION

This anatomic study suggests that posterior TDR removal is possible in the lumbar spine without undue risk to the surrounding nervous structures.

Effect of previous surgery on clinical outcome following 1-level lumbar arthroplasty

OBJECT

A secondary lumbar surgery at a previously surgically treated level is believed to result in minimal clinical improvement. The clinical results of the CHARITE Investigational Device Exemption (IDE) study were analyzed to assess the effect of previous surgery on clinical outcomes following either total disc replacement with the CHARITE device or anterior lumbar interbody fusion with a BAK cage and iliac crest autograft.

METHODS

Patients with prior microdiscectomy, laminectomy, or minimal medial facetectomy were not excluded from enrollment in the CHARITE IDE study. Thus, the following 3 groups were analyzed: all patients treated with the CHARITE Artificial Disc, whether randomized or nonrandomized; only patients treated with CHARITE devices randomized against patients with BAK devices; and control patients with BAK devices. Each group was further subdivided based on the patients' medical history, whether they had undergone prior surgery (prior surgery group) or had not (no prior surgery group). For all groups, baseline demographics were collected and compared for any potential recruitment bias. Postoperative improvements based on Oswestry Disability Index (ODI), visual analog scale (VAS), and patient satisfaction scores were further collected and statistically analyzed.

RESULTS

For all 3 groups, there were no statistical differences in clinical improvement from 3 months to 2 years postoperatively as measured using ODI and VAS scores between the subgroups (those who had prior surgery and those who did not).

CONCLUSIONS

Patients indicated for 1-level lumbar arthroplasty with previous lumbar decompressive surgery can be expected to have similar clinical outcomes to patients undergoing arthroplasty without prior lumbar decompressive surgery. Similarly, candidates for anterior lumbar fusion with prior decompressive surgery may experience similar benefits from the surgical procedure as those without.

Distribution of in vivo and in vitro range of motion following 1-level arthroplasty with the CHARITE artificial disc compared with fusion

OBJECT

One of the goals of lumbar arthroplasty is to restore and maintain range of motion (ROM) and to protect adjacent levels from abnormal motion, which may be a factor in transition syndrome following arthrodesis. In this study, in vitro ROM results were compared with in vivo, 2-year postoperative radiographic ROM evaluations.

METHODS

Radiographs of patients enrolled in the CHARITE investigational device exemption study were analyzed at baseline and at 2 years postoperatively. The ROM in flexion/extension at the implanted and adjacent levels was measured, normalized, and compared with ROM results obtained using cadaver (in vitro) evaluations.

RESULTS

Preoperative ROM distributions in patients enrolled for arthroplasty or fusion at the L4-5 level was as follows: 28% motion was observed at L3-4, 35% at L4-5 and 37% at L5-S1. Following a one-level arthroplasty at L4-5, the in vivo ROM distribution from L-3 to S-1 at the 2-year time point was 36% at L3-4, 30% at L4-5 and 35% at L5-S1. Following a one-level fusion with BAK and pedicle screws at L4-5, the in vivo ROM distribution from L-3 to S-1 at the 2-year time point was 45% at L3-4, 9% at L4-5 and 46% at L5-S1.

CONCLUSIONS

The baseline as well as the 2-year in vivo data confirmed previously published in vitro data. One-level arthroplasty was shown herein to replicate the normal distribution of motion of the intact spine.

Effect of age on clinical and radiographic outcomes and adverse events following 1-level lumbar arthroplasty after a minimum 2-year follow-up

Object

Lumbar arthroplasty is approved in the US for the treatment of degenerative disc disease at 1 level in skeletally mature patients. However, a bias toward older patients (> 45 years of age) who are otherwise indicated for the procedure may exist. In this study, the clinical outcomes of patients from the Charité Investigational Device Exemption (IDE) study were analyzed on the basis of patient age.

Methods

There were 276 patients enrolled in the IDE study of the Charité Artificial Disc who underwent 1-level arthroplasty at either L4–5 or L5–S1, including 71 nonrandomized and 205 randomized individuals. Patient data were analyzed based on age (18–45 years [217 patients, Group 1] compared with 46–60 years [59 patients, Group 2]). Statistical analyses were performed based on 2-year postoperative improvements in Oswestry Disability Index (ODI), 36-item Short Form Health Survey (SF-36), and visual analog scale (VAS) scores (clinical outcome), as well as range of motion (radiographic outcome), and adverse events.

Results

There was no significant difference between the groups with respect to level implanted, operative time, blood loss, changes in ODI and VAS scores or any of the 8 component scores of the SF-36, compared with baseline, at all time points throughout the 24-month follow-up period (p > 0.10). Patient satisfaction was equivalent at 24 months, with 87% satisfaction in Group 1 and 85% satisfaction in Group 2 (no statistical difference). In addition, no significant differences were identified with respect to adverse events including approach related, neurological, technique related, or reoperation.

Conclusions

Although patients > 45 years of age may have comorbidities or contraindications for arthroplasty for a number of reasons, particularly osteopenia, this analysis demonstrates that patients who are indicated for 1-level arthroplasty experience similar clinical outcome, satisfaction, or adverse events compared with their younger counterparts.

Patient selection for lumbar arthroplasty and arthrodesis: the effect of revision surgery in a controlled, multicenter, randomized study

Object

Patient selection is perhaps the most important factor in successful lumbar surgery. In this study, the authors analyzed the clinical outcomes of patients enrolled in the CHARITÉ investigational device exemption (IDE) trial who underwent revision surgery after primary total disc replacement with CHARITÉ or an anterior lumbar interbody fusion (ALIF) with placement of a BAK cage and iliac crest autograft. This revision surgery was either a supplemental posterior lumbar fixation or a 360° fusion. Statistical analysis was conducted to compare clinical success in patients who underwent revision surgery with those who did not.

Methods

The patients enrolled in the CHARITÉ IDE study were divided into 6 groups according to treatment and repeated operation status, and their Oswestry Disability Index (ODI) and visual analog scale (VAS) scores at the 2-year follow-up and at baseline were compared. The patients had received the following treatments by group: A) ALIF without reoperation; B) ALIF with conversion to 360° fusion; C) arthroplasty (randomized) without repeated operation; D) arthroplasty with supplemental posterior lumbar fixation; E) arthroplasty (nonrandomized) without repeated operation; and F) arthroplasty (nonrandomized) with supplemental posterior lumbar fixation. Outcome scores in the groups of patients who required revision surgeries (Groups B, D, and F; 23 patients) were compared with the groups that did not require revision surgery (Groups A, C, and E; 299 patients).

Results

Patients who required revision surgery had a significantly lower level of clinical improvement than those who did not. The mean change in ODI score was −53.0% in Groups A, C, and E, but just −12.7% in Groups B, D, and F (p < 0.0001). The mean change in VAS score was −59.1% in Groups A, C, and E, compared to −23.4% in Groups B, D, and F (p < 0.0001). No significant differences were identified in analyzing absolute change in scores and the percentage change. A comparison of outcomes in patients who had undergone arthroplasty without reoperation (Groups C and E) with all patients who had undergone revision surgery (Groups B, D, and F) demonstrated similar results (p < 0.0001).

Conclusions

The 7.1% of patients who underwent a secondary stabilization procedure had poor clinical improvement. This finding may indicate that if the alternative treatment had been the initial treatment, these patients would not have benefited, and further implies a 7.1% rate of imprecision in preoperative evaluation.

Comparison of biomechanical function at ideal and varied surgical placement for two lumbar artificial disc implant designs: mobile-core versus fixed-core

STUDY DESIGN

Finite element model.

OBJECTIVES

To estimate the effect of lumbar mobile-core and fixed-core artificial disc design and placement on the loading of the facet joints, and stresses on the polyethylene core.

SUMMARY OF BACKGROUND DATA

Although both mobile-core and fixed-core lumbar artificial disc designs have been used clinically, the effect of their design and the effect of placement within the disc space on the structural element loading, and in particular the facets and the implant itself, have not been investigated.

METHODS

A 3D nonlinear finite element model of an intact ligamentous L4-L5 motion segment was developed and validated in all 6 df based on previous experiments conducted on human cadavers. Facet loading of a mobile-core TDR and a fixed-core TDR were estimated with 4 different prosthesis placements for 3 different ranges of motion.

RESULTS

Placing the mobile-core TDR anywhere within the disc space reduced facet loading by more than 50%, while the fixed-core TDR increased facet loading by more than 10% when compared with the intact disc in axial rotation. For central (ideal) placement, the mobile- and fixed-core implants were subjected to compressive stresses on the order of 3 MPa and 24 MPa, respectively. The mobile-core stresses were not affected by implant placement, while the fixed-core stresses increased by up to 40%.

CONCLUSION

A mobile-core artificial disc design is less sensitive to placement, and unloads the facet joints, compared with a fixed-core design. The decreased core stress may result in a reduced potential for wear in a mobile-core prosthesis compared with a fixed-core prosthesis, which may increase the functional longevity of the device.

Revision and explantation strategies involving the CHARITE lumbar artificial disc replacement

STUDY DESIGN

A large case series of anterior revision surgery in patients who had complications following lumbar total disc replacement with the CHARITE artificial disc.

OBJECTIVES

To analyze and discuss the etiology of implant-related complications and to present a strategy that can be applied to lumbar intervertebral disc prostheses in cases where anterior revision surgery is necessary.

SUMMARY OF BACKGROUND DATA

This report represents the largest single-site, consecutive case series reported in the literature of anterior revision surgery following lumbar disc arthroplasty.

METHODS

A total of 18 patients are included in this study. All patients required an anterior revision procedure for repositioning or removal of the prosthesis. The mean time to revision was 6 months (range, 9 days to 4 years).

RESULTS

In 17 of 20 cases, implant removal was required and the patient was converted to a fusion. In 3 cases, primary revision of the CHARITE artificial disc was performed. Six revision cases were performed within the early postoperative period, defined as 7 to 14 days. All early cases were approached via reexploration of the original anterior midline retroperitoneal incision. Late revision was required in 14 cases, ranging from 3 weeks to 4 years following initial arthroplasty. A variety of surgical approaches were used in late revisions, including the lateral transpsoas approach at L3-L4 or L4-L5 (n = 5), expanded ipsilateral left retroperitoneal approach at L4-L5 (n = 2), contralateral right retroperitoneal approach at L5-S1 (n = 6), and transperitoneal approach (n = 1). Following 20 consecutive, anterior revision procedures, implant revision was successfully achieved in all cases.

CONCLUSIONS

Total disc replacement implant revisions occur largely as a result of technical errors in positioning and sizing of the implant. In addition, adherence to strict patient selection criteria will eliminate many cases of implant failure. When necessary, anterior revision surgery can be performed safely when a strategic approach is used.

Long-term results of one-level lumbar arthroplasty: minimum 10-year follow-up of the CHARITE artificial disc in 106 patients

STUDY DESIGN

A retrospective chart and radiographic review.

OBJECTIVES

To determine the long-term clinical results, radiographic results, and incidence of complications in a large patient cohort with one-level lumbar total disc replacement (TDR).

SUMMARY OF BACKGROUND DATA

Prior authors have described short-term, mid-term, and long-term clinical and radiographic results in patients with lumbar TDR with highly variable results.

METHODS

From January 1989 to November 1995, 108 patients, with a mean age of 36.4 years, underwent lumbar TDR with the CHARITE Artificial Disc, with 106 available for follow-up. A modified Stauffer-Coventry scale was used to determine clinical outcome. Return to work, work level, and the incidence of complications were assessed. Dynamic lateral flexion-extension and lateral bending radiographs were performed and segmental range of motion (ROM) was measured using the Cobb method.

RESULTS

Mean follow-up time was 13.2 years (range, 10-16.8 years). Of the 106 patients, 87 (82.1%) had either an excellent or good clinical outcome. Of the 96 patients working before surgery, 86 returned to work (89.6%), including 77.8% of patients with hard labor level employment (28 of 36) returning to the same level of work. The mean ROM in flexion-extension was 10.1 degrees , in lateral bending it was 4.4 degrees , and 90.6% of implanted prostheses were still mobile. Eight patients (7.5%) required posterior instrumented fusion. There were 5 cases (4.6%) of postoperative facet arthrosis, 3 cases (2.8%) of subsidence, 3 cases (2.8%) of adjacent-level disease, and 2 cases (1.9%) of core subluxation.

CONCLUSIONS

This retrospective study demonstrates the safety and efficacy of the CHARITE Artificial Disc at one level, either L4-L5 or L5-S1, in the long-term. Clinical outcomes and the rate of return to work were excellent overall. The rate of adjacent-level disease requiring surgical intervention was considerably lower (2.8%) compared with reports in the literature for lumbar fusion. As with any surgical procedure, proper indications play a pivotal role in clinical success.

Treatment of lumbar spinal stenosis with a total posterior arthroplasty prosthesis: implant description, surgical technique, and a prospective report on 29 patients

Object

Total disc replacement is an alternative to lumbar fusion, but patients with spinal stenosis, spondylolisthesis, and facet arthropathy are often excluded from this procedure because increased adjacent-segment motion can exacerbate dorsal spondylotic changes. In such cases of degenerative spondylolisthesis with stenosis, decompression and fusion remain the gold standard of treatment. To avoid attendant loss of motion at the treated segment, the TOPS system is a novel total posterior arthroplasty prosthesis that allows for an alternative dynamic, multiaxial, three-column stabilization and motion preservation. The purpose of this study is to report preliminary surgical data and clinical outcomes in patients treated with the TOPS lumbar total posterior arthroplasty system.

Methods

Twenty-nine patients were enrolled in a nonrandomized, multicenter, prospective pilot study outside the US. All patients had spinal stenosis and/or spondylolisthesis at L4–5 due to facet arthropathy. Radiographs and scores on outcome measures including the visual analog scale (VAS) for pain, Oswestry Disability Index (ODI), Short Form-36, and Zurich Claudication Questionnaire were prospectively recorded before surgery and at 6-week, 3-month, 6-month, and 1-year intervals after surgery. Prior to instrumentation, a bilateral total facetectomy and laminectomy at L4–5 or L3–4 was performed via a standard midline posterior approach. After decompression, the TOPS screws were inserted into four pedicles to achieve maximal purchase with triangulating bicortical trajectories. An appropriately sized TOPS arthroplasty implant was then applied.

The mean surgical time was 3.1 hours, and patients' clinical status improved significantly following treatment with the TOPS device. The mean ODI score decreased compared with baseline by 41% at 1 year, and the 100-mm VAS score declined by 76 mm over the same time period. Radiographic analysis showed that lumbar motion was maintained, disc height was preserved, and no evidence of screw loosening was found. No device malfunctions or migrations and no device-related adverse events were reported during the study.

Conclusions

The TOPS total posterior arthroplasty system represents a novel, dynamic, posterior arthroplasty device that provides multiaxial stability in flexion, extension, rotation, and lateral bending after total facetectomy and neural decompression. The surgical data indicate that it can be safely applied via a traditional approach with low surgical morbidity and excellent 1-year functional and radiographic outcomes in patients with degenerative spondylolisthesis accompanied by stenosis and back pain.

Therapy for early reperfusion after stroke

Ischemic stroke is a leading cause of death and disability in the Western world. At present, intravenous administration of tissue plasminogen activator within 3 h of symptom onset is the only proven effective treatment to re-establish cerebral blood flow in the case of acute vessel occlusion. Unfortunately, few patients presenting with acute ischemic stroke qualify for intravenous tissue plasminogen activator therapy. The focus of current research is, therefore, to find new treatment options by which to obtain early reperfusion, and to extend the therapeutic window for intervention beyond 3 h. The purpose of this Review is to provide an integrated view of the current state of reperfusion therapy in patients with acute stroke, including pharmacologic agents and the methods of delivery. The focus will be on intravenous and intra-arterial use of plasminogen activators in acute supratentorial infarction. Other therapies, such as antiplatelet agents (i.e. glycoprotein IIb/IIIa inhibitors), and anticoagulant drugs will be discussed briefly.

Evaluation of surgical volume and the early experience with lumbar total disc replacement as part of the investigational device exemption study of the Charité Artificial Disc

STUDY DESIGN

A prospective, randomized, multicenter, Food and Drug Administration regulated Investigational Device Exemption (IDE) clinical trial.

OBJECTIVES

To discern whether there is a correlation between surgical volume and clinical outcomes, as well as the complication rate and perioperative data points, for lumbar total disc replacement. To examine the early experience for lumbar total disc replacement as part of an IDE study.

SUMMARY OF BACKGROUND DATA

To our knowledge, an analysis of the effect of surgical volume has not been performed for any spine surgical procedure. Prior reports of the early experience with lumbar total disc replacement consist of retrospective reviews with nonspecific indications.

METHODS

An analysis was performed of the Food and Drug Administration IDE Study of the Charité Artificial Disc (DePuy Spine, Inc., Raynham, MA). Patients enrolled in the control group were omitted from the analysis. Up to 5 nonrandomized cases (representing the early experience) were performed at each site before beginning the randomized arm of the study. There were 3 comparisons performed: nonrandomized cases (71) versus randomized cases (205); randomized cases performed by high-enrolling surgeons versus low-enrolling surgeons; and randomized cases at high-volume institutions versus low-volume institutions.

RESULTS

The high-enrolling groups had a significantly lower mean hospital stay and operating time compared to the low-enrolling groups (P < 0.05). High-enrolling surgeons and institutions showed significantly shorter operating times, length of hospital stay, and complication rates. High-enrolling surgeons had significantly fewer device failures and cases of neurologic deterioration. Mean operating time and hospital stay were significantly lower in the randomized group (P < 0.05) compared to the nonrandomized group. Blood loss and approach-related complications were similar between the 2 groups. Device failure requiring removal was 4.2% in the nonrandomized group and 1.5% in the randomized group.

CONCLUSIONS

Surgeons and institutions with a high volume of lumbar total disc replacement cases have a reduction in key perioperative and postoperative parameters that provide a clinical and/or economic benefit. Surgeons may expect longer hospital stays, higher blood loss, and a higher rate of certain complications in their early experience with total disc replacement procedures, but there was no effect on clinical outcomes.

Immediate catheter-directed reperfusion for acute stroke occurring during diagnostic cardiac catheterization

Acute stroke is a rare but the most dreaded complication of cardiac catheterization. We report a case about the management of an acute stroke that occurred during a diagnostic cardiac catheterization procedure. Immediate catheter-based intraarterial thrombolysis with adjunctive balloon angioplasty of the left middle cerebral artery was carried out. The patient recovered markedly within the first 2 hr and was discharged without neurological sequelae after 3 days. A clinical pathway for acute stroke management in the catheterization laboratory is discussed.

Advances in treatment of acute ischemic stroke

Stroke carries a severe toll in terms of loss of life and disability for patients and their families. Until 10 years ago, physicians, and in particular neurologists, had a conservative, nonaggresive approach to this devastating disease. The advent of thrombolytic therapy not only proved that acute ischemic stroke is treatable, but also that early reperfusion can dramatically change the outcome of acute stroke patients. As a result of these trials, intravenous (IV) tissue plasminogen activator (t-PA) has been approved for treatment of acute ischemic stroke within 3 hours after symptom onset in the United States, Canada, Australia, and the European Union. The near future is extremely promising. Imaging modalities, such as diffusion- and perfusion-weighted images, as well as CT perfusion and CT angiography, to better select patients for treatment are now routinely performed in most academic medical centers. Novel IV and intra-arterial (IA) agents have been developed and tested. Emerging therapies will soon be available to increase the therapeutic windows for thrombolysis both by better screening patients using MRI or CT and by new IV and IA treatments. Several multicenter controlled trials in both imaging-guided decisions and therapeutic agents are either completed or being performed. We review data on advancement in imaging and treatment of acute ischemic stroke, in particular focusing on pharmacologic and mechanical IA thrombolysis.

Advances in treatment of acute ischemic stroke

Stroke carries a severe toll in terms of loss of life and disability for patients and their families. Until 10 years ago, physicians, and in particular neurologists, had a conservative, non-aggressive approach to this devastating disease. The advent of thrombolytic therapy not only proved that acute ischemic stroke is treatable, but also that early reperfusion can dramatically change the outcome of acute stroke patients. As a result of these trials, intravenous (IV) tissue plasminogen activator (t-PA) has been approved for treatment of acute ischemic stroke within 3 hours after symptom onset in the United States, Canada, Australia, and the European Union. The near future is extremely promising. Imaging modalities, such as diffusion- and perfusion-weighted images, as well as CT perfusion and CT angiography, to better select patients for treatment are now routinely performed in most academic medical centers. Novel IV and intra-arterial (IA) agents have been developed and tested. Emerging therapies will soon be available to increase the therapeutic windows for thrombolysis both by better screening patients using MRI or CT and by new IV and IA treatments. Several multicenter controlled trials in both imaging-guided decisions and therapeutic agents are either completed or being performed. We review data on advancement in imaging and treatment of acute ischemic stroke, in particular focusing on pharmacologic and mechanical IA thrombolysis.

[Diagnosis and therapy of basilar artery occlusion]

In view of the poor prognosis for untreated patients with basilar artery occlusion, rapid delivery of effective treatment has the highest priority. Early recanalization by intra-arterial thrombolysis can improve the outcome in some patients. Apart from this method, specialized centers are increasingly using mechanical devices and glycoprotein IIb/IIIa inhibitors to achieve recanalization. This review focuses on current developments in the diagnosis and treatment of acute basilar artery occlusion.

Mechanical Embolectomy

Mechanical embolectomy in acute ischemic stroke employs the use of novel endovascular devices to revascularize occluded intracerebral arteries. Devices like the Merci Retiever and other endovascular snares, laser thrombectomy and rheolytic/obliterative microcatheters, intracranial balloon angioplasty and stenting, and intra-arterial and transcranial ultrasound-enhanced chemical thrombolysis are intended to improve tissue rescue and diminish reperfusion hemorrhage while broadening the population eligible for therapy. Patient selection with MRI- and CT-based stroke protocols can detect tissue at risk and may obviate the classic limitations of the stroke therapeutic time window. These devices are being developed and modified at a rapid pace, requiring mounting endovascular expertise, and are being used successfully alone or in conjunction with chemical thrombolysis with relative safety.

Antiplatelet Therapy in Neuroendovascular Therapeutics

Our understanding of the pharmacology of antiplatelet therapy continues to evolve rapidly. Although the existing data are primarily generated in the setting of interventional and preventative cardiology studies, these data may be extrapolated to guide the rational application of these agents in neuroendovascular procedures. Platelet function testing represents an increasingly available and practical method by which to verify the adequacy of therapy and guide clinical decision making. The optimal application of these agents will undoubtedly improve the risk profile of neuroendovascular procedures, increase the success rate of acute stroke intervention, and facilitate more effective secondary stroke prevention.

Recombinant tissue plasminogen activator (rtPA) for stroke. The perspective at 8 years

OBJECTIVE

To review the 8-year experience with recombinant tissue plasminogen activator (rtPA) for stroke, with commentary on ramifications for the approach to stroke treatment, directions in stroke research, and sociological aspects of stroke as a disease of concern in our society.

BACKGROUND

Approved in 1996, rtPA remains the only drug indicated for the treatment of ischemic stroke. Stroke treatment and research have evolved rapidly in response to opportunities and discoveries related to the advent of rtPA. The presence of rtPA has engendered an increased level of awareness about all aspects of stroke.

METHODOLOGY

Literature review was performed, focusing on topics that in the author's view are of greatest relevance to the use of rtPA in clinical practice and to the directions in which the presence of rtPA is moving the field of stroke treatment, research, and politics.

RESULTS

Challenges have been raised, and met, regarding the validity of the data upon which the approval for rtPA was based. Limitations in the use of rtPA include the brief time available for treatment, the need for rapid imaging and blood-pressure control, and the fact that large-artery occlusions respond poorly. The major risk of treatment is brain hemorrhage, and although predictors of hemorrhage are known, their presence does not constitute an absolute contraindication to treatment. A virtual subindustry has evolved to enhance the benefit and applicability of rtPA through refined imaging technology and the use of rtPA intra-aterially, as well as in combination with other agents and devices. Sociopolitically, rtPA has elevated the level of awareness of stroke and provided impetus for the stroke center movement and federal legislation to stop stroke.

CONCLUSION

The development of rtPA has been the most effective advance in the field of stroke. It has generated healthy debate regarding the design, performance, and interpretation of stroke trials, including cost-benefit considerations. rtPA has stimulated research in a multitude of areas, enhanced our understanding of stroke pathophysiology, and defined important limits and risks for urgent intervention. rtPA is the cornerstone of the stroke center movement, as well as legislation in behalf of stroke at the congressional level.