Philipp Taussky

Validation of frontal near-infrared spectroscopy as noninvasive bedside monitoring for regional cerebral blood flow in brain-injured patients

OBJECT Near-infrared spectroscopy (NIRS) offers noninvasive bedside measurement of direct regional cerebral arteriovenous (mixed) brain oxygenation. To validate the accuracy of this monitoring technique, the authors analyzed the statistical correlation of NIRS and CT perfusion with respect to regional cerebral blood flow (CBF) measurements. METHODS The authors retrospectively reviewed all cases in which NIRS measurements were obtained at a single, academic neurointensive care unit from February 2008 to June 2011 in which CT perfusion was performed at the same time as NIRS data was collected. Regions of interest were obtained 2.5 cm below the NIRS bifrontal scalp probe on CT perfusion with an average volume between 2 and 4 ml, with mean CBF values used for purposes of analysis. Linear regression analysis was performed for NIRS and CBF values. RESULTS The study included 8 patients (2 men, 6 women), 6 of whom suffered subarachnoid hemorrhage, 1 ischemic stroke, and 1 intracerebral hemorrhage and brain edema. Mean CBF measured by CT perfusion was 61 ml/100 g/min for the left side and 60 ml/100 g/min for the right side, while mean NIRS values were 75 on the right and 74 on the left. Linear regression analysis demonstrated a statistically significant probability value (p<0.0001) comparing NIRS frontal oximetry and CT perfusion-obtained CBF values. CONCLUSIONS The authors demonstrated a linear correlation for frontal NIRS cerebral oxygenation measurements compared with regional CBF on CT perfusion imaging. Thus, frontal NIRS cerebral oxygenation measurement may serve as a useful, noninvasive, bedside intensive care unit monitoring tool to assess brain oxygenation in a direct manner.

Number of burr holes as independent predictor of postoperative recurrence in chronic subdural haematoma.

Chronic subdural haematoma (cSDH) is one of the most frequent neurosurgical entities. Current treatment options include burr hole craniostomy, twist drill craniostomy or craniotomy. While burr hole craniostomy is the most often used technique, there are no studies analysing the use of one vs. two burr holes in respect to recurrence rates and complications. This retrospective study included 76 (age: 60 ± 12 years) patients presenting with cSDH admitted in our institution from January 2004 to December 2005. A total of 21 (27%) patients underwent bilateral craniostomy. The patients were assessed using the Markwalder Scale (2 ± 0.71), Glasgow Coma Scale (14 ± 1) and measuring the haematoma thickness (1.8 ± 0.7 cm). The decision to perform one or two burr hole was made according to the personal preference of the treating neurosurgeon. All patients underwent irrigation and placement of closed-system drainage. Out of the 97 haematoma, 63 (65%) haematomas were treated with two burr holes, whereas 34 (35%) were treated with one burr hole. Patients with one burr hole had a statistically significant (p < 0.05) higher recurrence rate (29 vs. 5%), longer average hospitalization length (11 vs. 9 days) and higher wound infection rate (9% vs. 0%). A multivariate regression analysis identified the number of holes as single predictor for postoperative recurrence rate (r2 = 0.12; p < 0.001). In this study, the treatment of cSDH with one burr hole only is associated with a significantly higher postoperative recurrence rate, longer hospitalization length and higher wound infection rate.

Age and salvageability: Analysis of outcome of patients older than 65 years undergoing craniotomy for acute traumatic subdural hematoma

BACKGROUND We are in an aging population and many elderly people are prone to falling and suffering an acute traumatic subdural hematoma (aSDH). Yet, the operative treatment of patients older than 65 years of age for aSDH remains controversial, and very limited data exists with regard to expected outcome in this elderly patient group. METHODS We retrospectively analyzed 37 consecutive patients (all >65 years) who underwent craniotomy for aSDH in our department between January 1, 2002 and December 31, 2007. RESULTS Thirty-seven consecutive patients (54% women, 46% men) were treated for aSDH by means of craniotomy and duraplasty. Median age was 73 years (interquartile range, 10 years). Thirty patients (81%) had significant comorbidities and 43% of patients were treated by anticoagulation or thrombocyte aggregation inhibitors. Median initial Glasgow coma scale score was 8 (interquartile range, 7), and 51% had pupillary abnormalities. Perioperative morbidity occurred in 12 of 37 patients (32%), and 13 patients died in the postoperative period (35%). Overall outcome according to Glasgow outcome scale (GOS) was favorable (GOS, 4 and 5) in 15 of 37 patients (41%); severely disabled (GOS, 3) in 8 of 37 (22%), and unfavorable (GOS, 1 and 2) in 14 of 37 (38%). CONCLUSIONS Craniotomy for patients older than 65 years of age remains controversial, and our case series seems to support the notion that surgical treatment is associated with significant postoperative morbidity, mortality, and adverse outcome. However, selected patients benefit from an intervention, with a good outcome in 41% of patients.

Endocrinological outcome after pituitary transposition (hypophysopexy) and adjuvant radiotherapy for tumors involving the cavernous sinus: Clinical article

OBJECT Stereotactic radiosurgery and fractionated stereotactic radiotherapy are commonly used in the treatment of residual or recurrent benign tumors of the skull base and cavernous sinus. A major risk associated with radiosurgical or radiotherapy treatment of residual or recurrent tumors adjacent to normal functional pituitary gland is radiation of the pituitary, which frequently leads to the development of hypopituitarism. The authors have used a technique of pituitary transposition to reduce the radiation dose to the normal pituitary gland in cases of planned radiosurgical treatment of residual tumor within the cavernous sinus. Here, the authors analyze the long-term endocrinological outcomes in patients with residual and recurrent tumors who undergo hypophysopexy and adjuvant radiosurgical or conformal fractionated radiotherapy treatment. METHODS Pituitary transposition involves placement of a fat graft between the normal pituitary gland and residual tumor in the cavernous sinus. A sellar exploration for tumor resection is performed, the pituitary gland is transposed from the region of the cavernous sinus, and the graft is interposed between the pituitary gland and the residual tumor. The residual tumor may then be treated with stereotactic radiosurgery or conformal fractionated radiation therapy. The authors evaluated endocrinological outcome, safety of the procedure, and postoperative complications in patients who underwent this procedure during a 7-year period. RESULTS Hypophysopexy has been used in 34 patients with nonfunctioning pituitary adenomas (19), functional pituitary adenomas (8), chordomas (2), meningiomas (2), chondrosarcoma (1), hemangiopericytoma (1), or hemangioma (1) involving the sella and cavernous sinus. Follow-up (radiographic and endocrinological) has been performed yearly in all patients. Two patients experienced postoperative endocrine deficits before radiosurgery (1 transient), but none of the patients developed new hypopituitarism during the median 4-year follow-up (range 1-8 years) after radiosurgery or fractionated stereotactic radiotherapy. CONCLUSIONS The increased distance between the normal pituitary gland and the residual tumor facilitates treatment of the tumor with radiosurgery or radiotherapy and effectively reduces the incidence of radiation injury to the normal pituitary gland when compared with historical controls.

Pipeline embolization device for the treatment of vertebral artery aneurysms: the fate of covered branch vessels

Introduction Preliminary studies suggest that flow-diverting stents may be suitable for the treatment of aneurysms of the posterior circulation. The safety and efficacy of using flow-diverting stents for vertebral artery (VA) aneurysms is not well defined. Objective To examine the fate of covering the posterior inferior cerebellar artery (PICA) in patients undergoing placement of a flow-diverting stent for VA aneurysm. Methods Consecutive patients who underwent placement of a Pipeline Embolization Device (PED) for treatment of an aneurysm of the V4 segment of the VA between April 2012 and June 2015 at our institution were retrospectively evaluated. Angiograms were reviewed to determine the patency of the PICA when the vessel origin was covered by the PED. Results 11 patients with VA aneurysms who underwent treatment with the PED were identified. In each case the device covered the origin of the PICA. Follow-up angiography in eight patients demonstrated thrombosis of the aneurysm with patency of the PICA. Conclusions Flow-diverting stents can be used for the treatment of VA aneurysms. When appropriately sized to the vessel wall and positioned in the VA, the device may cover the origin of the PICA without impairing flow through the branching artery.

Safety and efficacy of ticagrelor for neuroendovascular procedures. A single center initial experience

Introduction Although platelet response testing is controversial, up to one-third of neuroendovascular patients are ‘resistant’ to clopidogrel and are at risk for in stent thrombotic complications and may require alternative antiplatelet therapy. Ticagrelor is a new reversible ADP P2Y12 platelet receptor inhibitor with no known resistance. We describe the clinical experience with ticagrelor for neuroendovascular procedures as an alternative in clopidogrel P2Y12 platelet resistant patients. Methods We reviewed our cerebrovascular database for all patients who were non-responders to clopidogrel, defined as P2Y12% inhibition <30%, despite repeat clopidogrel loading dose of at least 600 mg, and who were then administered ticagrelor. Results 18 patients were non-responders to clopidogrel; 10 (56%) were men, eight (44%) were women, with a median age of 61 years (range 38–84). All patients received loading doses of at least 600 mg of clopidogrel and showed P2Y12 levels below 20% prior to ticagrelor administration. Patients were loaded with 180 mg of ticagrelor, and all but one patient showed an initial P2Y12 response above 60%. 11 patients underwent stenting, two underwent coiling, and five underwent treatment by pipeline embolization device. No patient experienced any adverse effects in the postoperative period related to the use of ticagrelor. Conclusions Ticagrelor offers an effective alternative to clopidogrel non-responders. All of our patients showed immediate platelet inhibition after a loading dose of 180 mg of ticagrelor, with no adverse effects. The cost of medication, patient compliance (twice a day doses), and reversible inhibition should be taken into consideration when using ticagrelor.

Pipeline Embolization Device with or without Adjunctive Coil Embolization: Analysis of Complications from the IntrePED Registry

SUMMARY: Flow diversion to treat cerebral aneurysms has revolutionized neurointerventional surgery. Because the addition of coils potentially increases the time and complexity of endovascular procedures, we sought to determine whether adjunctive coil use is associated with an increase in complications. Patients in the International Retrospective Study of Pipeline Embolization Device registry were divided into those treated with the Pipeline Embolization Device alone (n = 689 patients; n = 797 aneurysms; mean aneurysm size, 10.3 ± 7.6 mm) versus those treated with the Pipeline Embolization Device and concurrent coil embolization (n = 104 patients; n = 109 aneurysms; mean aneurysm size, 13.6 ± 7.8 mm). Patient demographics and aneurysm characteristics were examined. Rates of neurologic morbidity and mortality were compared between groups. The Pipeline Embolization Device with versus without coiling required a significantly longer procedure time (135.8 ± 63.9 versus 96.7 ± 46.2 min; P < .0001) and resulted in higher neurological morbidity (12.5% versus 7.8%; P = .13). These data suggest that either strategy represents an acceptable risk profile in the treatment of complex cerebral aneurysms and warrants further investigation.

Surgical Outcomes and Predictors of Stroke in a North American White and African American Moyamoya Population

BACKGROUND The majority of moyamoya surgical series have been confined to Asian and pediatric populations. Few have studied demographics, risk factors, and outcomes in adult North American populations. OBJECTIVE To examine outcomes after revascularization for moyamoya in white and African American adults and to assess for predictors of recurrent stroke. METHODS A retrospective review of 75 non-Asian patients undergoing 110 procedures at the Mayo Clinic was performed. Demographics, known moyamoya associations, cerebrovascular risk factors, and autoimmune diseases were recorded. Primary outcomes for vascular events were assessed with Kaplan-Meier analysis. Fisher exact methods were used to evaluate for associations with recurrent events. RESULTS Mean age was 42 years, and mean follow-up was 47 months. Seventy-one of the 75 patients were white. The majority had bilateral disease (n = 49). Perioperative ischemic events occurred in 5 patients (4.5%). The 5- and 10-year event rates were 5.8% and 9.9%. Significant associations were found with a history of thyroid disease (P = .05) and recurrent stroke. A trend was also found between hypertension and autoimmune disease with recurrent stroke. CONCLUSION Outcomes were favorable with revascularization in this subset with moyamoya. A significant association between a history of thyroid disease and recurrent stroke was found. Additionally, high prevalences of autoimmune disease, hypertension, and thyroid disease were found in our cohort, suggesting that they may play a role in the pathophysiology and progression of moyamoya disease in this population. A new classification for moyamoya is proposed based on these data.

Medical Therapy for Ischemic Stroke: Review of Intravenous and Intra-Arterial Treatment Options

BACKGROUND Thrombolytic therapy is of proven and substantial benefit for select patients with acute cerebral ischemia. Diagnostic options and medical treatment options for acute stroke ischemia have undergone enormous changes in the past decades. Whereas initially stroke treatment was reduced to prevention, management of symptoms, and rehabilitation, nowadays a multitude of different fibrinolytic drugs are available. The wide availability of computed tomography in the late 1980s made thrombolysis a real therapeutic option because it allowed a fast and accurate differentiation between ischemic and hemorrhagic stroke. METHODS This study reviews these developments and how they have shaped our current use and understanding of thrombolytics in the treatment of acute ischemic stroke. RESULTS Patient selection remains a central aspect of thrombolytic treatment, and to date, the use of different fibrinolytics has been studied in over 20 large randomized trials for different clinical settings, time windows, and routes of administration. These studies included over 7000 patients, and led to our current understanding of the use of thrombolysis in acute stroke. CONCLUSIONS Intravenous fibrinolytic therapy within the first 3 hours of ischemic stroke onset offers substantial benefits for virtually all patients with potentially disabling deficits. In the 3- to 4.5-hour treatment window, intravenous fibrinolytic therapy has been shown to offer moderate net benefits when applied to all patients with potentially disabling deficits. Intra-arterial fibrinolytic therapy in the 3- to 6-hour window offers moderate net benefits when applied to all patients with potentially disabling deficits and large-artery cerebral thrombotic occlusions.

Advanced imaging in acute ischemic stroke

The evaluation and management of acute ischemic stroke has primarily relied on the use of conventional CT and MRI techniques as well as lumen imaging sequences such as CT angiography (CTA) and MR angiography (MRA). Several newer or less-established imaging modalities, including vessel wall MRI, transcranial Doppler ultrasonography, and 4D CTA and MRA, are being developed to complement conventional CT and MRI techniques. Vessel wall MRI provides high-resolution analysis of both extracranial and intracranial vasculature to help identify previously occult lesions or characteristics of lesions that may portend a worse natural history. Transcranial Doppler ultrasonography can be used in the acute setting as a minimally invasive way of identifying large vessel occlusions or monitoring the response to stroke treatment. It can also be used to assist in the workup for cryptogenic stroke or to diagnose a patent foramen ovale. Four-dimensional CTA and MRA provide a less invasive alternative to digital subtraction angiography to determine the extent of the clot burden and the degree of collateral blood flow in large vessel occlusions. Along with technological advances, these new imaging modalities are improving the diagnosis, workup, and management of acute ischemic stroke- roles that will continue to expand in the future.