Microvascular decompression for hemifacial spasm secondary to vertebrobasilar dolichoectasia: surgical strategies, technical nuances and clinical outcomes.

Hemifacial spasm (HFS) due to direct compression of the facial nerve by a dolichoectatic vertebrobasilar artery is rare. Vessels are often non-compliant and tethered by critical brainstem perforators. We set out to determine surgical strategies and outcomes for this challenging disease. All patients undergoing surgery for HFS secondary to vertebrobasilar dolichoectasia were reviewed. Hospital records, clinic notes and radiographic imaging were collected for outcome measures. Seventeen patients (eight males, nine females) were identified. Sixteen patients (94%) were treated with Teflon pledgets (DuPont, Wilmington, DE, USA) and one (6%) patient had a vascular sling placed around a severely diseased vertebral artery. All patients had significant reduction in symptoms and 82% of patients had complete resolution of symptoms (average follow-up: 41.4 months). One patient suffered persistent facial nerve paresis and swallowing difficulty. Two other patients suffered a 1 point decrease in the House-Brackmann facial nerve grading scale. Four patients (23%) required re-operation (infection, cerebrospinal fluid leak, and two patients with delayed recurrence of HFS). Of the latter, one patient required repositioning of a Teflon pledget and another patient underwent a sling decompression. There were no perioperative strokes or death. Excellent relief of symptoms with acceptable preoperative morbidity can be achieved using Teflon pledgets alone in most cases. In recalcitrant cases, sling transposition can be used to further augment the decompression. Careful attention must be paid to prevent vascular kinking and preserve brainstem perforators.

Left retrosigmoid craniotomy for cavernous malformation of the middle cerebellar peduncle.

We present a 25-year-old female with a history of multiple intracranial cavernous malformations complaining of vertigo. Imaging is significant for increasing size of a lesion in her left cerebellar peduncle. Given the proximity to the lateral border of the cerebellar peduncle, a retrosigmoid approach was chosen. After performing a craniotomy that exposed the transverse-sigmoid sinus junction, the dura was open and reflected. The arachnoid was sharply opened and cerebrospinal fluid was aspirated to allow the cerebellum to fall away from the petrous bone. The cerebellopontine fissure was then opened to visualize the lateral wall of the cerebellar peduncle. The cavernous malformation was entered and resected. The video can be found here: http://youtu.be/P7mpVbaCiJE .

Primary histiocytic sarcoma of the brain mimicking cerebral abscess.

Histiocytic sarcoma is a rare malignancy with only 10 reports confirmed primarily involving the CNS. The diagnosis is dependent on the finding of malignant cells with histiocytic morphology and immunophenotype. The authors report a case of pathologically proven HS of the CNS. A 16-year-old boy presented with headaches, emesis, and altered sensorium. Noncontrast head CT scanning demonstrated a left parietal mass consistent with a tumor. Surgery was undertaken. Intraoperative findings revealed green-yellow exudates consistent with an abscess. Cultures were obtained and broad-spectrum antibiotics were started. The patient subsequently underwent multiple surgical procedures, including drainage and debulking of abscesses and hemicraniectomy. Two months after initial presentation, the patient's diagnosis of histiocytic sarcoma was confirmed. Pathological examination demonstrated necrotizing inflammation with preponderant neutrophil infiltration, variably atypical mononuclear and multinucleate histiocytes, and numerous mitoses. Additional immunohistochemistry studies confirmed immunoreactivity for CD68, CD45, CD45RO, and CD15 and were negative for CD3, CD20, melanoma cocktail, CD30, CD1a, CD34, HMB-45, and melan-A. Once the diagnosis of histiocytic sarcoma was confirmed, antibiotics were stopped and radiation therapy was undertaken. Despite treatment, the patient's neurological status continued to decline and the patient died 126 days after initial presentation. This case represents a rare confirmed example of CNS histiocytic sarcoma. A profound inflammatory infiltrate seen on pathology and green exudates seen intraoperatively make the condition difficult to distinguish from an abscess. Immunohistochemistry showing a histiocytic origin and negative for myeloid, dendritic, or other lymphoid markers is essential for the diagnosis. Further research is needed to establish consensus on treatment.

Malignant transformation of a vestibular schwannoma after gamma knife radiosurgery.

OBJECTIVE: To report a single case of malignant transformation of a vestibular schwannoma after radiosurgery and review the growing body of literature describing patients with malignant transformation of primary benign tumors after radiosurgery, including vestibular schwannoma. METHODS: A 46-year-old woman presented with right facial paresthesias and imaging consistent with a right-sided vestibular schwannoma (volume approximately 18.5 cm(3)). RESULTS: The patient underwent subtotal resection followed by Gamma Knife radiosurgery (GKRS) 6 months after surgery. Initial histology showed a benign vestibular schwannoma with an MIB-1 labeling index of 5.7%. At 43 months after GKRS, the patient underwent repeat subtotal resection of a benign vestibular schwannoma (MIB-1 labeling index 7.4%). At 59 months after GKRS, she underwent a third resection, and histology showed frank malignant transformation (MIB-1 labeling index 33.8%). CONCLUSIONS: Malignant vestibular nerve tumors are extremely rare; only 18 cases have been reported in the literature. Our patient is the sixth pathologically confirmed case of malignant transformation after radiosurgery, supporting the contention that radiosurgery itself may play a causative role in transformation. In a histologically benign lesion, the presence of an elevated MIB-1 labeling index may predispose toward malignant transformation in the setting of adjuvant radiosurgery.

Endoscopic resection of colloid cysts: use of a dual-instrument technique and an anterolateral approach.

OBJECTIVE: Endoscopic approaches are increasingly utilized to treat third ventricular colloid cysts but have been associated with lower rates of complete cyst wall resection. Our objective was to assess the results of colloid cyst resection via an anterolateral endoscopic approach with a dual-instrument technique, with an emphasis on completeness of cyst wall resection. METHODS: A retrospective review of the senior author's experience with 22 colloid cysts treated with endoscopic resection since 2004 was performed. Initial cyst size, completeness of resection, postoperative radiographic residual, recurrence at follow-up, need for reoperation, and neurologic morbidity were assessed. All cysts were approached from an anterolateral trajectory with two instruments working in concert through a single endoscope. RESULTS: Of 22 patients, near-total resection was obtained in 95%. In 3 cases, a very small, radiographically occult residual was left. Complete cyst wall resection was therefore obtained in 18 (82%). There were no cases of recurrence at follow-up in any patient. No patients required craniotomy or underwent re-resection. Fifteen of 16 (94%) patients with long-term clinical follow-up remained stable or improved. CONCLUSION: High rates of complete colloid cyst resection, with low morbidity, are possible with an anterolateral endoscopic approach with dual-instrument technique. These results support the findings of other endoscopists that show how technical modifications to traditional endoscopic approaches can produce favorable results.

Long-term clinical and radiographic stability after clip reconstruction of a midbasilar dissecting mycotic aneurysm.

OBJECTIVE: Mycotic aneurysm rupture has been described as a rare, universally fatal complication of central nervous system Coccidioides immitis meningitis. Recently, however, we reported the successful surgical management of a midbasilar dissecting mycotic aneurysm related to C. immitis meningitis in a 24-year-old pregnant woman with acquired immune deficiency syndrome. METHODS: A 24-year-old pregnant woman with known acquired immune deficiency syndrome and a history of C. immitis meningitis presented to our institution with subarachnoid and intraventricular hemorrhage. Diagnostic cerebral angiography revealed a dissecting, midbasilar aneurysm involving the right anterior inferior cerebellar artery and causing stenosis of the proximal basilar artery. Through a retrosigmoid craniotomy, clip reconstruction of the basilar artery under hypothermic circulatory arrest was performed. The patient was neurologically intact at discharge (postoperative day 19) with the exception of mild disconjugate gaze and headache. RESULTS: At her 53-month follow-up, the patient was neurologically intact with only mild disconjugate gaze on upgaze. There was no evidence of local aneurysm recurrence or regional aneurysm formation, and the basilar artery was patent. Her C. immitis meningitis was well controlled. The patient is maintained on oral highly active antiretroviral therapy and an antifungal regimen. CONCLUSIONS: Our patient represents the only survivor of a C. immitis mycotic aneurysm rupture. In her case, long-term clinical and radiographic stability were achieved through a vigilant multidisciplinary approach.

Subaxial cervical juxtafacet cysts: single institution surgical experience and literature review.

OBJECTIVES: Juxtafacet cysts (JFCs) of the subaxial cervical spine are rare causes of neurological deficits. Their imaging characteristics, relationship to segmental instability, and potential for inducing acute symptomatic deterioration have only been described in a few case reports and small case series. The objective of the current study was to review the surgical experience at our center and across the literature to better define these variables. METHODS: A single-institution, multisurgeon series of 12 consecutive patients (mean age 63.4 years, range 52-83 years) harboring 14 JFCs treated across 9 years was retrospectively reviewed. Clinical history, neurological status, preoperative imaging, operative findings, pathology, and postoperative outcomes were obtained from medical records. The mean follow up was 9.2 ± 7.8 months. A literature review identified 35 studies with 89 previously reported cases of surgically treated subaxial cervical JFCs. RESULTS: Consistent with previously reported cases, most JFCs in our series involved the C7/T1 level. Nine patients reported axial neck pain, 12 patients had radicular symptoms, four patients had myelopathy, and one patient experienced rapid neurological decline attributable to cystic hemorrhage. Cyst expansion without hemorrhage caused subacute deterioration in one patient. All patients experienced sensory and/or motor improvement following surgical decompression. Preoperative axial neck pain improved in eight of nine patients (89 %). Seven out of 12 patients (58 %) underwent fusion either at the time of decompression (six patients) or at a delayed timepoint within the follow-up period (one patient). Prior history of cervical instrumentation, hypermobility on dynamic imaging, and other risk factors for segmental instability were more common in our series than in previous reports. CONCLUSIONS: Our findings lead us to advocate for early decompression rather than prolonged conservative treatment, for pre- and postoperative dynamic imaging, and for fusion in selected cases as an initial surgical consideration.

A simple and quantitative method to predict symptomatic vasospasm after subarachnoid hemorrhage based on computed tomography: beyond the Fisher scale.

BACKGROUND: Although the Fisher scale is commonly used to grade vasospasm risk in aneurysmal subarachnoid hemorrhage (aSAH) patients, it fails to account for increasing subarachnoid hemorrhage (SAH) thickness. OBJECTIVE: We developed a simple quantitative scale based on maximal SAH thickness and compared its reproducibility and ability to predict symptomatic vasospasm against the Fisher scale. METHODS: The incidence of radiographic and symptomatic vasospasm among 250 aSAH patients treated at our institution was investigated. Admission head computed tomography scans were graded according to the Fisher scale and the proposed scale, which assigns a score from 1 to 5 based on a single measurement of maximum SAH thickness. We calculated vasospasm risk per grade for the Fisher scale and the proposed scale, and compared inter- and intraobserver variability for both scales. RESULTS: Forty-five patients (20.6%) developed symptomatic vasospasm. On the proposed scale, grade 5 patients were at highest risk, with an odds ratio for symptomatic vasospasm of 11 (95% confidence interval [CI] 2.27-53.37). Odds ratios for proposed grades 4 and 3 were 4.63 (95% CI 1.10-19.59) and 3.04 (95% CI 0.85-10.90), respectively. The odds ratio for Fisher grade 3 was 3.3 (0.96-11.30). Mean inter- and intraobserver agreement was greater for the proposed scale in comparison with the Fisher scale (κ0.65 and κ0.81 vs κ0.51 and κ0.35, respectively). CONCLUSION: The new scale accounted for increasing SAH thickness and was superior to the Fisher scale in inter- and intraobserver agreement and in predicting symptomatic vasospasm, particularly among the highest-risk patients.

Eagle's syndrome: embryology, anatomy, and clinical management.

BACKGROUND: Eagle's syndrome refers to a rare constellation of neuropathic and vascular occlusive symptoms caused by pathologic elongation or angulation of the styloid process and styloid chain. First described in 1652 by Italian surgeon Piertro Marchetti, the clinical syndrome was definitively outlined by Watt Eagle in the late 1940s and early 1950s. METHODS: This article reviews how underlying embryologic and anatomic pathology predicts clinical symptomatology, diagnosis, and ultimately treatment of the syndrome. RESULTS: The length and direction of the styloid process and styloid chain are highly variable. This variability leads to a wide range of relationships between the chain and the neurovascular elements of the neck, including cranial nerves 5, 7, 9, and 10 and the internal carotid artery. In the classic type of Eagle's syndrome, compressive cranial neuropathy most commonly leads to the sensation of a foreign body in the throat, odynophagia, and dysphagia. In the carotid type, compression over the internal carotid artery can cause pain in the parietal region of the skull or in the superior periorbital region, among other symptoms. CONCLUSIONS: Careful recording of the history of the present illness and review of systems is crucial to the diagnosis of Eagle's syndrome. After the clinical examination, the optimal imaging modality for styloid process pathology is spiral CT of the neck and skull base. Surgical interventions are considered only after noninvasive therapies have failed, the two most common being intraoral and external resection of the styloid process.

Survival and functional outcome after surgical resection of intramedullary spinal cord metastases.

OBJECTIVE: Intramedullary spinal cord metastasis (ISCM) is a rare manifestation of systemic cancer and data about the optimal management of these lesions are lacking. To clarify the role of surgery, we investigated survival and neurological outcomes after surgical resection of ISCMs. METHODS: Between 2003 and 2010, we surgically treated 10 ISCMs in 9 patients. For each patient, we retrospectively collected the following data: demographic variables, history of prior cancer, site of primary cancer, extent of cancer on presentation, degree of resection, preoperative and postoperative spinal cord impairment (American Spinal Injury Association [ASIA] grade), and postoperative survival. We investigated the relationship between these variables, overall survival, and preservation of function. RESULTS: Eight ISCMs were treated with gross total resection and two were treated with subtotal resection. Overall postoperative survival was 6.4 ± 9.4 months (mean ± standard deviation), with one patient still alive at last follow-up. Patients with a diagnosis of melanoma had higher mean survival than those with nonmelanoma histology (20.5 ± 13.4 vs. 2.4 ± 1.7 months, P < 0.01). Degree of resection, number of organ systems affected, ambulatory status, and ASIA grade pre operatively or postoperatively, were not significantly associated with survival. Of the nine patients, seven (78%) demonstrated no change in ASIA grade postoperatively, one (11%) improved, and one patient (11%) deteriorated. All patients who were ambulatory preoperatively remained ambulatory postoperatively and at last follow-up. CONCLUSIONS: Although ISCM is associated with poor prognosis, survival appears to be greater in patients with melanoma. Surgical resection does not appear to significantly lengthen survival but may be indicated to preserve ambulatory status in symptomatic patients.

Supracerebellar infratentorial endoscopically controlled resection of pineal lesions: case series and operative technique.

OBJECT: The heterogeneous clinical manifestations and operative characteristics of pathological entities in the pineal region represent a significant challenge in terms of patient selection and surgical approach. Traditional surgical options have included endoscopic transventricular resection; open supratentorial microsurgical approaches through the midline, choroidal fissure, lateral ventricle, and tentorium; and supracerebellar infratentorial (SCIT) approaches through the posterior fossa. The object of the current study was to review the preoperative characteristics and outcomes for a cohort of patients treated purely via the novel endoscopically controlled SCIT approach. METHODS: A single-institution series of 9 consecutive patients (4 male and 5 female patients [10 total cases]; mean age 21 years, range 6-37 years) treated via the endoscopically controlled SCIT approach for a pathological entity in the pineal region was retrospectively reviewed. The mean follow-up time was 13.2 months. RESULTS: The endoscopically controlled SCIT approach was successfully used to approach a variety of pineal lesions, including pineal cysts (6 patients), epidermoid tumor, WHO Grade II astrocytoma (initial biopsy and recurrence), and malignant mixed germ cell tumor (1 patient each). Gross-total resection and/or adequate cyst fenestration was achieved in 8 cases. Biopsy with conservative debulking was performed for the single case of low-grade astrocytoma and again at the time of recurrence. The mean preoperative tumor and cyst volumes were 9.9 ± 4.4 and 3.7 ± 3.2 cm(3), respectively. The mean operating times were 212 ± 71 minutes for tumor cases and 177 ± 72 minutes for cysts. Estimated blood loss was less than 150 ml for all cases. A single case (pineal cyst) was converted to an open microsurgical approach to enhance visualization. There were no operative complications, as well as no documented CSF leaks, additional CSF diversion procedures, or air emboli. Seven patients underwent concomitant third ventriculostomy into the quadrigeminal cistern. At the time of the last follow-up evaluation, all patients had a stable or improved modified Rankin Scale score. CONCLUSIONS: The endoscopically controlled SCIT approach may be used for the biopsy and resection of appropriately selected solid tumors of the pineal region, in addition to the fenestration and/or resection of pineal cysts. Preoperative considerations include patient presentation, anticipated disease and vascularity, degree of local venous anatomical distortion, and selection of optimal paramedian trajectory.

Terminal ventriculostomy as an adjuvant treatment of complex syringomyelia: a case report and review of the literature.

Complex syringomyelia is multifactorial, and treatment strategies are highly individualized. In refractory cases, sectioning of the filum terminale, also known as terminal ventriculostomy, has been described as a potential adjuvant treatment to alleviate syrinx progression. A 10-year-old boy with a history of arachnoiditis presented with complex syringomyelia, progressive lower extremity motor weakness, and spasticity. Previously, he had failed spinal cord detethering and direct syrinx shunting. Imaging studies demonstrated a holocord syrinx extending to the level of his conus medullaris and into the filum terminale. The patient underwent an uncomplicated lumbar laminectomy and transection of the filum terminale. Operative pathologic specimens demonstrated a dilated central canal within the filum. Postoperative imaging demonstrated significant reduction in the diameter of the syrinx. At follow-up, the patient's motor symptoms had improved. Terminal ventriculostomy may be a useful adjuvant in treating caudally placed syringes refractory to other treatments. This procedure carries low neurological risk and involves no hardware implantation. In select cases, terminal ventriculostomy may help preserve neurological function in the face of otherwise progressive syringomyelia.

Delayed subarachnoid hemorrhage following failed odontoid screw fixation.

Iatrogenic vascular injury is a rare but potentially devastating complication of cervical spine instrumentation. The authors report on a patient who developed an anterior spinal artery pseudoaneurysm associated with delayed subarachnoid hemorrhage after undergoing odontoid screw placement 14 months earlier. This 86-year-old man presented with spontaneous subarachnoid hemorrhage (Fisher Grade 4) and full motor strength on neurological examination. Imaging demonstrated pseudarthrosis of the odontoid process, extension of the odontoid screw beyond the posterior cortex of the dens, and a pseudoaneurysm arising from an adjacent branch of the anterior spinal artery. Due to the aneurysm's location and lack of active extravasation, endovascular treatment was not attempted. Posterior C1-2 fusion was performed to treat radiographic and clinical instability of the C1-2 joint. Postoperatively, the patient's motor function remained intact. Almost all cases of vascular injury related to cervical spine instrumentation are recognized at surgery. To the authors' knowledge, this is the first report of delayed vascular injury following an uncomplicated cervical fixation. This case further suggests that the risk of this phenomenon may be elevated in cases of failed fusion.

Comparison of two antibiotic-impregnated ventricular catheters: a prospective sequential series trial.

BACKGROUND: External ventricular drains (EVDs) are valuable adjuncts in the management of neurosurgical patients but are associated with a significant risk of cerebrospinal fluid (CSF) infection (range, 0% to 27%); a review of 23 studies reported a mean of 8.8%. OBJECTIVE: To compare the efficacy of 2 different antibiotic-impregnated EVD catheters in preventing CSF infections. METHODS: Patients were prospectively enrolled in an Institutional Review Board-approved study. During alternating 3-month periods, all patients received either a minocycline/rifampin-impregnated (M/R) ventricular catheter or a clindamycin/rifampin-impregnated (C/R) EVD catheter. CSF cultures were collected at the time of insertion and twice weekly. Positive cultures were defined a priori as growth of the same bacteria on 2 media (eg, blood agar and broth) or 2 cultures of the same bacteria on 1 medium (eg, broth). RESULTS: Altogether, 129 patients (mean age, 58.4 years; 55 male) received 65 C/R catheters and 64 M/R catheters. The most common indications for EVD placement were aneurysmal subarachnoid hemorrhage (48.1%), spontaneous intraparenchymal hemorrhage (13.2%), and tumor (11.6%). The mean duration of ventriculostomy drainage was 11.8 and 12.7 days in the C/R and M/R groups, respectively. No positive CSF cultures were identified in either cohort. CONCLUSIONS: The use of antibiotic-impregnated catheters was associated with an extremely low risk of CSF infection compared with the reported mean of nearly 9% for standard EVD catheters. Infection rates for both C/R and M/R EVD catheters were zero. These results support the use of antibiotic-impregnated EVD catheters in routine clinical practice.

Comparison of dural grafts in Chiari decompression surgery: Review of the literature.

BACKGROUND: Decompression of Chiari malformation is a common procedure in both pediatric and adult neurosurgery. Although the necessity for some bony removal is universally accepted, other aspects of Chiari surgery are the subject of debate. The most controversial points include the optimal amount of bony removal, the use of duraplasty (and the type of material), the need for subarachnoid dissection, and the need for tonsillar shrinkage. MATERIAL AND METHODS: We critically reviewed the literature to elucidate the risks and benefits of different graft types and to clarify optimal treatment options therein. Based on our search results, 108 relevant articles were identified. With specific inclusion and exclusion criteria, we noted three studies that directly compared two tlpes of dural substitutes in Chiari malformation surgery. RESULTS: Our review did not support the superiority of either autologous or nonautologous grafts when duraplasty is employed. Our institutional experience, however, dictates that when the pericranium is available and of good quality, it should be utilized for duraplasty. It is non-immunogenic, inexpensive, and capable of creating a watertight closure with the dura. CONCLUSIONS: Discrepancies between the three comparative studies analyzed are likely attributable to increases in pericranial quality and thickness with maturity. Future randomized studies with large numbers and the power to resolve differences in the relatively low rates of complications in Chiari surgery are warranted.

A history of the Barrow Neurological Institute.

The Barrow Neurological Institute (BNI), founded in 1961, is in partnership with St. Joseph's Hospital and Medical Center and part of the Catholic Healthcare West system. The BNI is a relative newcomer to academic neuroscience. However, since its inception it has grown to become an international destination for neurologic disease. This article describes the history of the institute as it has grown over the years in its commitment to excellence in patient care, education, and research.

Identification of A2B5+CD133- tumor-initiating cells in adult human gliomas.

OBJECTIVE: Several studies have shown that human gliomas contain a small population of cells with stem cell-like features. It has been proposed that these "cancer stem cells" may be uniquely responsible for glioma formation and recurrence. However, human gliomas also contain an abundance of cells that closely resemble more differentiated glial progenitors. Animal model studies have shown that these cells also possess the capacity to form malignant gliomas. METHODS: To investigate the contributions of stem-like and progenitor-like cells in human gliomas, we used flow cytometry to characterize the expression of a cancer stem cell marker (CD133) and a glial progenitor marker (A2B5) in 25 tumors. We found that human gliomas consistently express A2B5 in a large percentage of cells (61.7 +/- 3.8%, standard error of the mean). In contrast, CD133 expression was less abundant and less consistent (14.8 +/- 3.6%, standard error of the mean), with several glioblastomas containing very few or no detectable CD133+ cells. When present, the CD133+ population was almost entirely contained within the A2B5+ population. Thus, most gliomas could be divided into three distinct populations on the basis of these markers (A2B5+CD133+, A2B5+CD133-, and A2B5-CD133-). To test the tumorigenic potential of these populations, we separated cells from six tumors by fluorescence-activated cell sorting and reinjected them into nude rats. RESULTS: We found that the capacity for these different populations to form tumors varied depending on the human tumor specimen from which they were isolated. Of the six human gliomas tested, four contained A2B5+/CD133- cells that formed tumors when transplanted into nude rats, three contained A2B5+/CD133+ cells that formed tumors, and only one glioma contained A2B5-/CD133- cells with the capacity to form tumors. CONCLUSION: Together, these results demonstrate that human gliomas contain multiple populations of cells with the capacity to form tumors and specifically identify a population of tumorigenic A2B5+ cells that are phenotypically distinct from CD133+ cells.

C3a receptor modulation of granulocyte infiltration after murine focal cerebral ischemia is reperfusion dependent.

The complement anaphylatoxin C3a contributes to injury after cerebral ischemia in mice. This study assesses the effect of C3a receptor antagonist (C3aRA) on leukocyte infiltration into the ischemic zone. Transient or permanent middle cerebral artery occlusion (MCAO) was induced in wild-type C57Bl/6 mice. Intraperitoneal C3aRA or vehicle was administered 45 mins before or 1 h after occlusion. Twenty-four hours after occlusion, we harvested brain tissue and purified inflammatory cells using flow cytometry. Soluble intercellular adhesion molecule (ICAM)-1 protein levels were assessed using enzyme-linked immunosorbent assays, and ICAM-1 and C3a receptor (C3aR) expression was confirmed via immunohistochemistry. In the transient MCAO model, animals receiving C3aRA showed smaller strokes, less upregulation of C3aR-positive granulocytes, and less ICAM-1 protein on endothelial cells than vehicle-treated animals; no significant differences in other inflammatory cell populations were observed. C3a receptor antagonist-treated and vehicle-treated animals showed no differences in stroke volume or inflammatory cell populations after permanent MCAO. These data suggest that blocking the binding of C3a to C3aR modulates tissue injury in reperfused stroke by inhibiting the recruitment of neutrophils to the ischemic zone. It further establishes antagonism of the C3a anaphylatoxin as a promising strategy for ameliorating injury after ischemia/reperfusion.