Publications by authors named "David B Niemann"

23 Publications

  • Page 1 of 1

Evaluation of previously embolized intracranial aneurysms: inter-and intra-rater reliability among neurosurgeons and interventional neuroradiologists.

J Neurointerv Surg 2018 May 16;10(5):462-466. Epub 2017 Sep 16.

Department of Neurosurgery, Icahn School of Medicine at Mount Sinai, New York, USA.

Background: The angiographic evaluation of previously coiled aneurysms can be difficult yet remains critical for determining re-treatment.

Objective: The main objective of this study was to determine the inter-rater reliability for both the Raymond Scale and per cent embolization among a group of neurointerventionalists evaluating previously embolized aneurysms.

Methods: A panel of 15 neurointerventionalists examined 92 distinct cases of immediate post-coil embolization and 1 year post-embolization angiographs. Each case was presented four times throughout the study, along with alterations in demographics in order to evaluate intra-rater reliability. All respondents were asked to provide the per cent embolization (0-100%) and Raymond Scale grade (1-3) for each aneurysm. Inter-rater reliability was evaluated by computing weighted kappa values (for the Raymond Scale) and intraclass correlation coefficients (ICC) for per cent embolization.

Results: 10 neurosurgeons and 5 interventional neuroradiologists evaluated 368 simulated cases. The agreement among all readers employing the Raymond Scale was fair (κ=0.35) while concordance in per cent embolization was good (ICC=0.64). Clinicians with fewer than 10 years of experience demonstrated a significantly greater level of agreement than the group with greater than 10 years (κ=0.39 and ICC=0.70 vs κ=0.28 and ICC=0.58). When the same aneurysm was presented multiple times, clinicians demonstrated excellent consistency when assessing per cent embolization (ICC=0.82), but moderate agreement when employing the Raymond classification (κ=0.58).

Conclusions: Identifying the per cent embolization in previously coiled aneurysms resulted in good inter- and intra-rater agreement, regardless of years of experience. The strong agreement among providers employing per cent embolization may make it a valuable tool for embolization assessment in this patient population.
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http://dx.doi.org/10.1136/neurintsurg-2017-013231DOI Listing
May 2018

Mask free Intravenous 3D Digital Subtraction Angiography (IV 3D-DSA) from a single C-arm acquisition.

Proc SPIE Int Soc Opt Eng 2016 22;9783. Epub 2016 Mar 22.

Department of Medical Physics, University of Wisconsin-Madison, WI 53705.

Currently, clinical acquisition of IV 3D-DSA requires two separate scans: one mask scan without contrast medium and a filled scan with contrast injection. Having two separate scans adds radiation dose to the patient and increases the likelihood of suffering inadvertent patient motion induced mis-registration and the associated mis-registraion artifacts in IV 3D-DSA images. In this paper, a new technique, SMART-RECON is introduced to generate IV 3D-DSA images from a single Cone Beam CT (CBCT) acquisition to eliminate the mask scan. Potential benefits of eliminating mask scan would be: (1) both radiation dose and scan time can be reduced by a factor of 2; (2) intra-sweep motion can be eliminated; (3) inter-sweep motion can be mitigated. Numerical simulations were used to validate the algorithm in terms of contrast recoverability and the ability to mitigate limited view artifacts.
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http://dx.doi.org/10.1117/12.2216869DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5710838PMC
March 2016

Familial perimesencephalic subarachnoid hemorrhage: two case reports.

J Med Case Rep 2014 Nov 22;8:380. Epub 2014 Nov 22.

Department of Neurological Surgery, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA.

Introduction: Non-aneurysmal spontaneous subarachnoid hemorrhage is characterized by an accumulation of a limited amount of subarachnoid hemorrhage, predominantly around the midbrain, and a lack of blood in the brain parenchyma or ventricular system. It represents 5% of all spontaneous subarachnoid hemorrhage cases. In spite of extensive investigation, understanding of the mechanisms leading to perimesencephalic non-aneurysmal subarachnoid hemorrhage remains incompletely defined. A growing body of evidence has supported a familial predisposition for non-aneurysmal spontaneous subarachnoid hemorrhage.

Case Presentation: A 39-year-old Caucasian man presented with sudden onset headache associated with diplopia. His computed tomography scan revealed perimesencephalic subarachnoid hemorrhage. A cerebral angiogram showed no apparent source of bleeding. He was treated conservatively and discharged after 1 week without any neurological deficits. The older brother of the first case, a 44-year-old Caucasian man, presented 1.5 years later with acute onset of headache and his computed tomography scan also showed perimesencephalic non-aneurysmal subarachnoid hemorrhage. He was discharged home with normal neurological examination 1 week later. Follow-up angiograms did not reveal any source of bleeding in either patient.

Conclusions: We report the cases of two siblings with perimesencephalic non-aneurysmal subarachnoid hemorrhage, which may further suggest a familial predisposition of non-aneurysmal spontaneous subarachnoid hemorrhage and may also point out the possible higher risk of perimesencephalic non-aneurysmal subarachnoid hemorrhage in the first-degree relatives of patients with perimesencephalic non-aneurysmal subarachnoid hemorrhage.
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http://dx.doi.org/10.1186/1752-1947-8-380DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4275759PMC
November 2014

Neuroangiography simulation using a silicone model in the angiography suite improves trainee skills.

J Neurointerv Surg 2014 Sep 23;6(7):561-4. Epub 2013 Sep 23.

Department of Neurologic Surgery, University of Wisconsin, Madison, Wisconsin, USA.

Purpose: Simulation techniques in neurosurgical training are becoming more important. The purpose of this study was to determine whether silicone vascular models used in the angiography suite can render improvement in trainee performance and safety in neuroendovascular procedures.

Methods: 10 residents from neurosurgery and radiology training programs were asked to perform a diagnostic angiogram on a silicone based vascular model (United Biologics, Tustin, USA). This was done in the angiography suite with the full biplane fluoroscopy machine (Siemens, Munich, Germany). On their first attempt, they were coached by a faculty member trained in endovascular neurosurgery; on their second attempt, they received coaching only if the procedure had stalled. Technique was scored on multiple criteria by the faculty, and total time and fluoroscopy time were recorded on both attempts.

Results: In this group of 10 residents, overall procedure time significantly decreased from 51 to 42 min (p=0.01), and total fluoro time significantly decreased from 12 to 9 min (p=0.002) between the first attempt and the second attempt. Technical skill increased significantly in navigation, vessel selection, projection setup, and road map usage.

Conclusions: Silicone vascular models used in the angiography suite, with the clinical working tools and biplane fluoroscopy, provide a valuable experience for training residents in diagnostic angiography, and improved performance and safety.
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http://dx.doi.org/10.1136/neurintsurg-2013-010826DOI Listing
September 2014

Demographic, circadian, and climatic factors in non-aneurysmal versus aneursymal subarachnoid hemorrhage.

Clin Neurol Neurosurg 2013 Mar 6;115(3):298-303. Epub 2012 Jul 6.

Department of Neurological Surgery, School of Medicine and Public Health, University of Wisconsin, Madison, WI 53792, USA.

Background: Although, the relationship of spontaneous subarachnoid hemorrhage (SAH) to climatic or circadian factors has been widely studied, epidemiologic, circardian and climatic factors in non-aneurysmal SAH (naSAH), particularly perimesencephalic SAH (PMH), has not been reported before.

Objective: For the first time, demographic, climatic, and circadian variables are examined together as possible contributing factors comparing aSAH and naSAH.

Methods: We reviewed records for 384 patients admitted to University of Wisconsin Neurosurgery Service from January 2005 to December 2010 with spontaneous non-traumatic SAH. Patients were grouped as aSAH (n=338) or naSAH (n=46) on clinical and radiological criteria. PMH (n=32) was identified as a subgroup of naSAH based on radiological criteria. We logged demographic data, time of SAH, temperature at onset and atmospheric pressure at onset. The three subgroups were compared.

Results: Aneurysmal SAH occurred most often from 6am to 12pm (p<0.001); this correlation was not found in naSAH or PMH subgroups. Demographic analysis demonstrated predominance of female gender (p=0.008) and smoking (p=0.002) in aSAH, with predominance of hypercholesterolemia in naSAH (p=0.033). Atmospheric pressure, correlated with aSAH in the main county referral area, where we had detailed weather data (p<0.05); however, there was no weather correlation in the entire referral region taken together. Multivariate analysis supported a statistical difference only in smoking status between aSAH and naSAH groups (p=0.0159).

Conclusion: Statistical differences in gender, smoking status, and history of hypercholesterolemia support a clinical distinction between aSAH and naSAH. Furthermore, circadian patterning of aSAH is not reproduced in naSAH, supporting pathophysiologic differences. Only smoking status provides a robust difference in aSAH and naSAH groups. Our data prompt further investigation into the relationship between aSAH and atmospheric pressure.
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http://dx.doi.org/10.1016/j.clineuro.2012.05.039DOI Listing
March 2013

Bilateral A1 fenestrations: Report of two cases and literature review.

Surg Neurol Int 2012 16;3:43. Epub 2012 Apr 16.

Department of Neurological Surgery, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA.

Background: Bilateral fenestration of the A1 segment of anterior cerebral artery (ACA) is an uncommon anomaly. Our objective is to describe two cases with this anomaly and to review the literature.

Case Description: A 50-year-old woman presented with subarachnoid hemorrhage from a ruptured A1 aneurysm. Angiography revealed bilateral A1 segment fenestration as well as an aneurysm on the proximal end of fenestration on the right side. The second case is that of an 86-year-old woman who was found to have bilateral fenestration of A1 segment at autopsy.

Conclusion: Bilateral A1 fenestration is an uncommon anomaly that may be associated with an aneurysm. In surgical clipping of such cases, extreme caution should be exercised to inspect both arms of the fenestration since both may have multiple perforators as demonstrated in our autopsy specimen. This will be the first published pictorial demonstration of these perforators arising from the arms of fenestration.
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http://dx.doi.org/10.4103/2152-7806.94928DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3347490PMC
October 2012

Superselective Wada test for ruptured spontaneous fusiform middle cerebral artery aneurysm: a technical case report.

J Neurointerv Surg 2011 Sep 2;3(3):237-41. Epub 2011 Feb 2.

Department of Neurosurgery, University of Wisconsin Medical School, Madison, Wisconsin 53792, USA.

Background: Spontaneous fusiform aneurysms of the middle cerebral artery (sfaMCA) are quite uncommon and tend to occur in young adults. The use of superselective angiography for ruptured and unruptured aneurysms can help delineate vital angioarchitecture and assist with perioperative planning and treatment modality. The use of superselective Wada testing (SWT) for treatment of a ruptured sfaMCA involving the dominant hemisphere, however, has never been described in the English literature. We report a case of a ruptured sfaMCA involving the dominant hemisphere where superselective angiography and SWT were utilized to predict the ability to occlude a major vessel without adverse neurological sequelae.

Case Description: A healthy young patient presented with subarachnoid hemorrhage. Initial CT-angiogram of the head identified a left-sided fusiform MCA aneurysm measuring 1.3 cm by 0.5 cm in maximum dimensions. Diagnostic angiography evaluation demonstrated an irregular, fusiform aneurysm involving the central (Rolandic) trunk of the left MCA. An SWT was then performed through an SL 10 microcatheter with injection of sodium amytal. Verbal, motor and cognitive testing were performed twice and revealed no neurological defects. The patient underwent subsequent coil embolization of the aneurysm. Formal post-procedure evaluation revealed no speech, language or cognitive deficits. She was eventually discharged home and remained without neurological deficits at her follow-up appointment 12 months after her initial presentation.

Conclusion: Intraoperative SWT can be performed as part of the initial evaluation for patients with sfaMCA of the dominant cerebral hemisphere to help choose the appropriate treatment algorithm and predict post-treatment neurological deficits.
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http://dx.doi.org/10.1136/jnis.2010.002220DOI Listing
September 2011

U.S. Wingspan Registry: 12-month follow-up results.

Stroke 2011 Jul 2;42(7):1976-81. Epub 2011 Jun 2.

Stony Brook University Medical Center, Department of Neurological Surgery, Health Sciences Center T-12 080, Stony Brook, NY 11794, USA.

Background And Purpose: The purpose of this study is to present 12-month follow-up results for a series of patients undergoing percutaneous transluminal angioplasty and stenting with the Gateway-Wingspan stenting system (Boston Scientific) for the treatment of symptomatic intracranial atherostenosis.

Methods: Clinical and angiographic follow-up results were recorded for patients from 5 participating institutions. Primary end points were stroke or death within 30 days of the stenting procedure or ipsilateral stroke after 30 days.

Results: During a 21-month study period, 158 patients with 168 intracranial atherostenotic lesions (50% to 99%) were treated with the Gateway-Wingspan system. The average follow-up duration was 14.2 months with 143 patients having at least 3 months of clinical follow-up and 110 having at least 12 months. The cumulative rate of the primary end point was 15.7% for all patients and 13.9% for patients with high-grade (70% to 99%) stenosis. Of 13 ipsilateral strokes occurring after 30 days, 3 resulted in death. Of these strokes, 76.9% (10 of 13) occurred within the first 6 months of the stenting procedure and no events were recorded after 12 months. An additional 9 patients experienced ipsilateral transient ischemic attack after 30 days. Most postprocedural events (86%) could be attributed to interruption of antiplatelet medications (n=6), in-stent restenosis (n=12), or both (n=1). In 3 patients, the events were of uncertain etiology.

Conclusions: After successful Wingspan percutaneous transluminal angioplasty and stenting, some patients continued to experience ipsilateral ischemic events. Most of these ischemic events occurred within 6 months of the procedure and were associated with the interruption of antiplatelet therapy or in-stent restenosis.
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http://dx.doi.org/10.1161/STROKEAHA.111.613877DOI Listing
July 2011

Flexible thin film electrode arrays for minimally-invasive neurological monitoring.

Annu Int Conf IEEE Eng Med Biol Soc 2009 ;2009:5506-9

Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI 53706 USA.

We present approaches for using thin film polymeric electrode arrays for use in applications of minimally invasive neurological monitoring. The flexibility and unique surface properties of the thin-film polyimide substrate in combination with a compact device platform make them amenable to a variety of surgical implantation procedures. Using a rapid-prototyping and fabrication technique, arrays of various geometries can be fabricated within a week. In this paper we test two different approaches for deploying electrode arrays through small cranial openings.
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http://dx.doi.org/10.1109/IEMBS.2009.5333177DOI Listing
April 2010

Target lesion revascularization after wingspan: assessment of safety and durability.

Stroke 2009 Jan 16;40(1):106-10. Epub 2008 Oct 16.

Barrow Neurosurgical Associates, Ltd, Phoenix-Main Office, 2910 N. 3 Avenue, Phoenix, AZ 85013, USA.

Background And Purpose: In-stent restenosis (ISR) occurs in approximately one-third of patients after the percutaneous transluminal angioplasty and stenting of intracranial atherosclerotic lesions with the Wingspan system. We review our experience with target lesion revascularization (TLR) for ISR after Wingspan treatment.

Methods: Clinical and angiographic follow-up results were recorded for all patients from 5 participating institutions in our US Wingspan Registry. ISR was defined as >50% stenosis within or immediately adjacent (within 5 mm) to the implanted stent and >20% absolute luminal loss.

Results: To date, 36 patients in the registry have experienced ISR after percutaneous transluminal angioplasty and stenting with Wingspan. Of these patients, 29 (80.6%) have undergone TLR with either angioplasty alone (n=26) or angioplasty with restenting (n=3). Restenting was performed for in-stent dissections that occurred after the initial angioplasty. Of the 29 patients undergoing TLR, 9 required >/=1 interventions for recurrent ISR, for a total of 42 interventions. One major complication, a postprocedural reperfusion hemorrhage, was encountered in the periprocedural period (2.4% per procedure; 3.5% per patient). Angiographic follow-up is available for 22 of 29 patients after TLR. Eleven of 22 (50%) demonstrated recurrent ISR at follow-up angiography. Nine patients have undergone multiple retreatments (2 retreatments, n=6; 3 retreatments, n=2; 4 retreatments, n=1) for recurrent ISR. Nine of 11 recurrent ISR lesions were located within the anterior circulation. The mean age for patients with recurrent anterior circulation ISR was 57.9 years (vs 81 years for posterior circulation ISR).

Conclusions: TLR can be performed for the treatment of intracranial Wingspan ISR with a relatively high degree of safety. However, the TLR results are not durable in approximately 50% of patients, and multiple revascularization procedures may be required in this subgroup.
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http://dx.doi.org/10.1161/STROKEAHA.108.525774DOI Listing
January 2009

Angiographic patterns of Wingspan in-stent restenosis.

Neurosurgery 2008 Jul;63(1):23-7; discussion 27-8

Department of Neurosurgery, Barrow Neurological Institute, Phoenix, Arizona, USA.

Objective: A classification system developed to characterize in-stent restenosis (ISR) after coronary percutaneous transluminal angioplasty with stenting was modified and applied to describe the appearance and distribution of ISR occurring after Wingspan (Boston Scientific, Fremont, CA) intracranial percutaneous transluminal angioplasty with stenting.

Methods: A prospective, intention-to-treat, multicenter registry of Wingspan treatment for symptomatic intracranial atherosclerotic disease was maintained. Clinical and angiographic follow-up results were recorded. ISR was defined as greater than 50% stenosis within or immediately adjacent (within 5 mm) to the implanted stent(s) and greater than 20% absolute luminal loss. ISR lesions were classified by angiographic pattern, location, and severity in comparison with the original lesion treated.

Results: Imaging follow-up (3-15.5 months) was available for 127 intracranial stenotic lesions treated with Wingspan percutaneous transluminal angioplasty with stenting. Forty-one lesions (32.3%) developed either ISR (n = 36 [28.3%]) or complete stent occlusion (n = 5 [3.9%]) after treatment. When restenotic lesions were characterized using the modified classification system, 25 of 41 (61.0%) were focal lesions involving less than 50% of the length of the stented segment: three were Type IA (focal stenosis involving one end of the stent), 21 were Type IB (focal intrastent stenosis involving a segment completely contained within the stent), and one was Type IC (multiple noncontiguous focal stenoses). Eleven lesions (26.8%) demonstrated diffuse stenosis (>50% of the length of the stented segment): nine were Type II with diffuse intrastent stenosis (completely contained within the stent) and two were Type III with proliferative ISR (extending beyond the stented segment). Five stents were completely occluded at follow-up (Type IV). Of the 36 ISR lesions, 16 were less severe or no worse than the original lesion with respect to severity of stenosis or length of the segment involved; 20 lesions were more severe than the original lesion with respect to the segment length involved (n = 5), actual stenosis severity (n = 6), or both (n = 9). Nine of 10 supraclinoid internal carotid artery ISR lesions and nine of 13 middle cerebral artery ISR lesions were more severe than the original lesion.

Conclusion: Wingspan ISR typically occurs as a focal lesion. In more than half of ISR cases, the ISR lesion was more extensive than the original lesion treated in terms of lesion length or stenosis severity. Supraclinoid internal carotid artery and middle cerebral artery lesions have a propensity to develop more severe posttreatment stenosis.
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http://dx.doi.org/10.1227/01.NEU.0000335067.53190.A2DOI Listing
July 2008

Frequency of thromboembolic events associated with endovascular aneurysm treatment: retrospective case series.

J Neurosurg 2008 Jun;108(6):1095-100

Department of Neurological Surgery, University of Wisconsin at Madison, WI, USA.

Object: There is little evidence addressing whether procedures requiring adjunctive devices lead to an increased frequency of thromboembolic complications. The authors report their experience with 155 aneurysms treated with and without adjunctive devices.

Methods: The authors retrospectively reviewed their last 155 aneurysm coil placement procedures. The patients' records were reviewed for the following phenomena: 1) evidence of procedure-related thrombus formation; 2) clinical evidence of stroke; and 3) the presence of acute ischemia in the treated vascular territory on diffusion-weighted (DW) imaging.

Results: Of the 155 aneurysms treated in 132 patients, 66 were treated with coils only, 45 had stent-assisted coil placement, 33 underwent balloon remodeling, and in 11 stents were placed after balloon remodeling. Small DW imaging abnormalities were present in the treated vascular territory in 24% of cases (37 lesions). Specifically, 21 (32%) of 66 lesions in the coil-treated group, 6 (13%) of 45 in the stent-assisted coil treatment group, 8 (24%) of 33 in the balloon remodeling group, and 2 (18%) of 11 in the balloon and stent group showed DW imaging positivity. Furthermore, 25 (68%) of the 37 cases that were positive on DW imaging occurred in patients presenting with subarachnoid hemorrhage (SAH). Clinically evident stroke or transient ischemic attack was present in 10 (27%) of 37 cases, with 70% occurring in patients presenting with SAH.

Conclusions: Use of adjunctive devices in treating aneurysms does not appear to increase the frequency of embolic or ischemic events. The presence of DW imaging abnormalities and clinically evident stroke was actually less frequent when adjunctive devices were used and in electively treated cases. This was probably related to perioperative antiplatelet medical management.
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http://dx.doi.org/10.3171/JNS/2008/108/6/1095DOI Listing
June 2008

Alternative vascular graft for extracranial-intracranial bypass surgery: descending branch of the lateral circumflex femoral artery.

Neurosurg Focus 2008 ;24(2):E8

Department of Neurological Surgery, University of Wisconsin, Madison, USA.

Object: Arterial bypass is an important method of treating intracranial disease requiring sacrifice of the parent vessel. The conduits for extracranial-intracranial (EC-IC) bypass surgery include the superficial temporal artery, occipital artery, superior thyroid artery, radial artery, and saphenous vein (long or short). In an aging population with an increased prevalence of vascular disease, conduits for EC-IC bypass may be in short supply in some patients. Herein, the authors describe a case in which the descending branch of the lateral circumflex femoral artery (DLCFA) was utilized as a high-flow conduit for an EC-IC bypass.

Methods: This 22-year-old woman presented with irregular menstrual periods, secondary amenorrhea, and hypothyroidism. A giant intrasellar and suprasellar mass was found. Angiography confirmed a 3.5 x 2.1-cm fusiform aneurysm involving the cavernous and supraclinoid segments of the right internal carotid artery. A suitable radial artery conduit was not available. The DLCFA was harvested and anastomosed between the M(2) segment of the middle cerebral artery and the external carotid artery.

Results: Durable clinical and angiographic results were apparent at the 2-month follow-up.

Conclusions: The DLCFA's diameter and length were used successfully in a high-flow EC-IC bypass surgery. The DLCFA may be a good alternative to radial artery and saphenous vein grafts for an EC-IC bypass requiring high flow.
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http://dx.doi.org/10.3171/FOC/2008/24/2/E8DOI Listing
April 2008

Wingspan in-stent restenosis and thrombosis: incidence, clinical presentation, and management.

Neurosurgery 2007 Sep;61(3):644-50; discussion 650-1

Department of Neurosurgery, School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Millard Fillmore Gates Hospital, Kaleida Health, Buffalo, New York, USA.

Objective: Wingspan (Boston Scientific, Fremont, CA) is a self-expanding stent designed specifically for the treatment of symptomatic intracranial atheromatous disease. The current series reports the observed incidence of in-stent restenosis (ISR) and thrombosis on angiographic follow-up.

Methods: A prospective, intent-to-treat registry of patients in whom the Wingspan stent system was used to treat symptomatic intracranial atheromatous disease was maintained at five participating institutions. Clinical and angiographic follow-up results were recorded. ISR was defined as stenosis greater than 50% within or immediately adjacent (within 5 mm) to the implanted stents and absolute luminal loss greater than 20%.

Results: To date, follow-up imaging (average duration, 5.9 mo; range, 1.5-15.5 mo) is available for 84 lesions treated with the Wingspan stent (78 patients). Follow-up examinations consisted of 65 conventional angiograms, 17 computed tomographic angiograms, and two magnetic resonance angiograms. Of these lesions with follow-up, ISR was documented in 25 and complete thrombosis in four. Two of the 4 patients with stent thrombosis had lengthy lesions requiring more than one stent to bridge the diseased segment. ISR was more frequent (odds ratio, 4.7; 95% confidence intervals, 1.4-15.5) within the anterior circulation (42%) than the posterior circulation (13%). Of the 29 patients with ISR or thrombosis, eight were symptomatic (four with stroke, four with transient ischemic attack) and 15 were retreated. Of the retreatments, four were complicated by clinically silent in-stent dissections, two of which required the placement of a second stent. One was complicated by a postprocedural reperfusion hemorrhage.

Conclusion: The ISR rate with the Wingspan stent is higher in our series than previously reported, occurring in 29.7% of patients. ISR was more frequent within the anterior circulation than the posterior circulation. Although typically asymptomatic (76% of patients in our series), ISR can cause neurological symptoms and may require target vessel revascularization.
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http://dx.doi.org/10.1227/01.NEU.0000290914.24976.83DOI Listing
September 2007

Utilization of self-expanding stents in the treatment of intracranial atherosclerotic disease in the distal small cerebral vessels.

Neuroradiology 2007 Aug 27;49(8):659-63. Epub 2007 Mar 27.

Department of Neurosurgery, University of Wisconsin Hospital and Clinics, 600 Highland Ave., Madison, WI, USA.

Introduction: Previously, endovascular treatment of stenosis related to intracranial atherosclerosis (ICAD) involving arteries measuring less than 2 mm in diameter was limited. To our knowledge, there are no reports in the literature addressing stent placement for treatment of stenosis in arteries of this size.

Methods: Four patients aged 33 to 80 years (mean 57.5 years) with medically refractory ICAD underwent angioplasty and stenting of small (<2 mm) distal intracerebral arteries. Vessel location and length of follow-up were anterior cerebral artery (ACA) A1 segment (5 months), ACA A2 segment (18 months), middle cerebral artery M1 segment (18 months), and posterior cerebral artery P1 segment (8 months) with vessel calibers ranging from 1.2 to 1.8 mm. Clinical and imaging follow-up ranged from 5 to 18 months.

Results: All procedures were successfully performed without complications. Follow-up out to 18 months demonstrated one vessel that went on to occlusion while the other stented vessel segments remained patent. One patient died 8 months after stenting, but the death was not related to neurological disease. The remaining patients experienced resolution of the presenting symptomatology and remained asymptomatic throughout follow-up.

Conclusion: In this small series, stenoses of distal (<2 mm) cerebral arteries were amenable to treatment using new self-expanding stents. We safely and successfully treated four arteries smaller than 2 mm in diameter with newer self-expanding stents. All patients remained clinically asymptomatic. One stent occluded at 5 months and the others remained patent during follow-up. Longer term clinical follow-up is required to determine the durability and viability of this therapy.
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http://dx.doi.org/10.1007/s00234-007-0229-xDOI Listing
August 2007

US multicenter experience with the wingspan stent system for the treatment of intracranial atheromatous disease: periprocedural results.

Stroke 2007 Mar 8;38(3):881-7. Epub 2007 Feb 8.

Department of Neurosurgery, Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA.

Background And Purpose: The current report details our initial periprocedural experience with Wingspan (Boston Scientific/Target), the first self-expanding stent system designed for the treatment of intracranial atheromatous disease.

Methods: All patients undergoing angioplasty and stenting with the Gateway balloon-Wingspan stent system were prospectively tracked.

Results: During a 9-month period, treatment with the stent system was attempted in 78 patients (average age, 63.6 years; 33 women) with 82 intracranial atheromatous lesions, of which 54 were > or =70% stenotic. Eighty-one of 82 lesions were successfully stented (98.8%) during the first treatment session. In 1 case, the stent could not be delivered across the lesion; the patient was treated solely with angioplasty and stented at a later date. Lesions treated involved the internal carotid (n=32; 8 petrous, 10 cavernous, 11 supraclinoid segment, 3 terminus), vertebral (n=14; V4 segment), basilar (n=14), and middle cerebral (n=22) arteries. Mean+/-SD pretreatment stenosis was 74.6+/-13.9%, improving to 43.5+/-18.1% after balloon angioplasty and to 27.2+/-16.7% after stent placement. Of the 82 lesions treated, there were 5 (6.1%) major periprocedural neurological complications, 4 of which ultimately led to patient death within 30 days of the procedure.

Conclusions: Angioplasty and stenting for symptomatic intracranial atheromatous disease can be performed with the Gateway balloon-Wingspan stent system with a high rate of technical success and acceptable periprocedural morbidity. Our initial experience indicates that this procedure represents a viable treatment option for this patient population.
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http://dx.doi.org/10.1161/01.STR.0000257963.65728.e8DOI Listing
March 2007

Utility of computed tomography perfusion in detection of cerebral vasospasm in patients with subarachnoid hemorrhage.

Neurosurg Focus 2006 Sep 15;21(3):E6. Epub 2006 Sep 15.

Department of Neurosurgery, University of Wisconsin Hospital and Clinics, Madison, Wisconsin, USA.

Object: Digital subtraction (DS) angiography is the gold standard for detecting cerebral vasospasm after subarachnoid hemorrhage (SAH). Computed tomography (CT) perfusion is a recently developed modality for the evaluation of cerebral hemodynamics. This study was conducted to evaluate the potential of using CT perfusion to detect vasospasm in patients with SAH.

Methods: Fourteen patients between the ages of 41 and 66 years with aneurysmal SAH underwent 23 CT perfusion scans for suspected vasospasm. All patients underwent DS angiography within 12 hours of the CT perfusion scans. The presence of vasospasm on CT perfusion images was determined based on qualitative reading using color maps of mean transit time, cerebral blood flow, and cerebral blood volume as criteria. The presence or absence of vasospasm as retrospectively determined using CT perfusion was compared with DS angiography findings. Of the 23 CT perfusion scans performed, 21 (91%) were concordant with angiography findings in predicting the presence or absence of vasospasm. In 15 of 23 scans, the presence of vasospasm was detected on CT perfusion scans and confirmed on DS angiography studies. In two cases, vasospasm was revealed on DS angiography but was not confirmed on CT perfusion. The degree of agreement between CT perfusion and DS angiography for detection of vasospasm was high (K = 0.8, p , 0.0001).

Conclusions: Computed tomography perfusion is an accurate, reliable, and noninvasive method to detect the presence or absence of vasospasm. It can be used as a tool to help guide the decision to pursue DS angiography with the intent to treat vasospasm.
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http://dx.doi.org/10.3171/foc.2006.21.3.6DOI Listing
September 2006

Evaluation of cerebral hemodynamics with computed tomography perfusion using gadolinium as an alternative to iodinated contrast: a case report.

J Comput Assist Tomogr 2006 Mar-Apr;30(2):307-9

Department of Neurosurgery, University of Wisconsin Hospital and Clinics, Madison, WI 53792, USA.

Computed tomography (CT) perfusion is traditionally performed using iodinated contrast, but this can be problematic in patients with impaired renal function or contrast allergy. We report a case of a 63-year-old man whose medical history was complicated by chronic renal failure, which was exacerbated after placement of a left cervical internal carotid artery stent by 70% stenosis and left hemisphere perfusion deficit. On a follow-up clinic visit, because of the patient s chronic renal failure, CT perfusion was performed successfully using gadolinium without further renal complications.
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http://dx.doi.org/10.1097/00004728-200603000-00027DOI Listing
June 2006

Effects of carotid or vertebrobasilar stent placement on cerebral perfusion and cognition.

AJNR Am J Neuroradiol 2005 Aug;26(7):1772-80

Department of Neurosurgery, University of Wisconsin Hospital and Clinics, Madison, WI, USA.

Introduction: There are no well-established physiologic or neuropsychological criteria for identifying which patients with stenosis of the cervicocerebral vessels are at high risk of stroke or cognitive impairment. Our purpose was to evaluate changes in cognitive performance and cerebral perfusion associated with endovascular stent placement of the cervicocerebral vessels.

Methods: A consecutive series of 20 patients, 31-88 years of age, who underwent 21 stent procedures for arterial stenosis (10 extracranial carotid stents [ECS], four intracranial carotid stents [ICS], and seven extra- or intracranial vertebrobasilar stents [VBS]) was investigated retrospectively. All patients were evaluated with CT or MR perfusion studies both before and after stent placement. Cognitive response after stent placement was evaluated by using an informant questionnaire.

Results: In patients with anterior circulation stenoses (ECS and ICS group), 11 of 14 (79%) had a baseline perfusion abnormality and all 11 patients showed improved perfusion after stent placement. Four of seven (57%) patients with posterior circulation stenoses (VBS group) had a baseline perfusion abnormality and two of the four patients showed improved perfusion after stent placement. Degree of stenosis was the strongest predictor of the presence of a baseline perfusion abnormality (P = .03). Fifteen of 19 (79%) of the patients showed improved cognitive scores after stent placement. Among patients with improvement in perfusion after stent placement, 11 of 13 (85%) had improved cognitive scores. Improved perfusion after stent placement was a significant predictor of cognitive improvement (P = .04). Patients who were stented on an elective basis demonstrated greater improvement in cognition as compared with patients stented urgently (P = .01).

Conclusion: Endovascular stent placement of the cervicocerebral vessels can safely and effectively resolve cerebral perfusion abnormalities. Improvement in perfusion parameters is associated with cognitive improvement. Larger, blinded, prospective studies are needed to confirm these preliminary observations.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7975161PMC
August 2005

Intracranial endovascular stent placement for symptomatic metastatic non-hodgkin lymphoma. Case report.

J Neurosurg 2005 May;102(5):922-6

Department of Neurosurgery, University of Wisconsin Medical School, Madison, Wisconsin 53792, USA.

A case of cranial-based metastatic non-Hodgkin lymphoma with cerebral vascular compromise is presented. The patient underwent intracranial endovascular stent placement resulting in an improvement in his symptoms. This is the first reported case of endovascular stent placement for an intracranial neoplasm in the literature to date.
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http://dx.doi.org/10.3171/jns.2005.102.5.0922DOI Listing
May 2005

Intraoperative perfusion computerized tomography scanning for management of intracranial stent placement in a patient with tandem intracranial stenoses. Case report.

J Neurosurg 2005 May;102(5):918-21

Department of Radiology, University of Wisconsin Hospital and Clinics, Madison, Wisconsin 53792, USA.

The authors describe the novel use of cerebral perfusion computerized tomography studies to evaluate the effectiveness of internal carotid artery stent placement in a man with symptomatic transient ischemic attacks caused by tandem stenoses of the internal carotid and middle cerebral arteries.
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http://dx.doi.org/10.3171/jns.2005.102.5.0918DOI Listing
May 2005

Transverse venous sinus stent placement as treatment for benign intracranial hypertension in a young male: case report and review of the literature.

J Neurosurg 2005 Apr;102(3 Suppl):342-6

Departments of Neurosurgery and Radiology, University of Wisconsin Medical School, Madison, Wisconsin 53792, USA.

Venous outlet obstruction has recently been reported to be a potentially treatable cause of benign intracranial hypertension (BIH). In the English-language literature only 18 cases, all from the UK and Australia, involving the use of transverse sinus stenosis stent treatment for BIH have been reported; the youngest patient to receive treatment was a 17-year-old girl. The authors report the case of a 15-year-old boy who presented with headache, papilledema, decreased visual acuity, and diploplia who underwent successful unilateral transverse sinus stenosis stenting and experienced complete resolution of symptoms.
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http://dx.doi.org/10.3171/ped.2005.102.3.0342DOI Listing
April 2005

Treatment of intracerebral hematomas caused by aneurysm rupture: coil placement followed by clot evacuation.

J Neurosurg 2003 Nov;99(5):843-7

Department of Neurosurgery, Radcliffe Infirmary, Oxford, United Kingdom.

Object: The aim of this study was to evaluate the efficacy of a treatment combination of coil embolization and clot evacuation in patients presenting with an intracerebral hematoma (ICH) caused by the rupture of an aneurysm.

Methods: Twenty-seven patients were prospectively recruited in this study between 1996 and 2000. Endovascular treatment of the putative ruptured aneurysm was performed as soon as practical after diagnosis and before surgical evacuation of the ICH. The Glasgow Outcome Scale (GOS) was used during follow up. Despite admission World Federation of Neurosurgical Societies grades of IV or V in 25 patients (92%), 13 (48%) recovered well with GOS scores of 1 or 2, whereas six patients (21%) died.

Conclusions: The combined result of a favorable outcome in 48% of the patients and a mortality rate of 21% indicates that this treatment may be a valuable alternative for this patient group and warrants further study.
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http://dx.doi.org/10.3171/jns.2003.99.5.0843DOI Listing
November 2003
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