Andreas Simgen

The Barrel stent: new treatment option for stent-assisted coiling of wide-necked bifurcation aneurysms—results of a single-center study

Purpose The Barrel stent is a laser cut stent designed for stent-assisted coil embolization of wide-necked bifurcation or branch aneurysms with a single device, with the purpose of lowering the metal-to-artery ratio and its inherent risk of thromboembolic complications of multiple stents. We report our early experiences with this device in 17 patients in this retrospective single-center analysis. Materials and methods 17 consecutive patients who underwent stent-assisted coil embolization of wide-necked bifurcation aneurysms with the Barrel stent were retrospectively identified. We analyzed the feasibility of successful deployment and post-treatment angiographic results. Adverse events, clinical outcome, and angiographic follow-up results were also analyzed. Results Aneurysms were located in the internal carotid artery (n=3), the middle cerebral artery (n=9), the anterior communicating artery (n=3), and the basilar artery (n=2). In the immediate post-treatment angiography, adequate occlusion (neck remnant or total occlusion) was observed in 16/17 (94.1%) of aneurysms. One patient experienced a transient ischemic attack. No permanent neurologic deficits were observed. 13/17 (76.5%) patients underwent short-term follow-up angiography after 3 months, all of which showed adequate occlusion of the aneurysm. Conclusions In this small retrospective single-center analysis we show that stent-assisted coiling with the Barrel stent is a safe and effective option for the endovascular treatment of intracranial wide-necked bifurcation aneurysms.

The Derivo Embolization Device, a Second-Generation Flow Diverter for the Treatment of Intracranial Aneurysms, Evaluated in an Elastase-Induced Aneurysm Model.

PurposeIn recent years, flow diverters have provided a promising alternative to treat complex intracranial aneurysms. In this study, we compare a second-generation flow-diverting device (Derivo Embolization Device) with its prototype flow diverter, in the treatment of elastase-induced aneurysms in New Zealand white rabbits.MethodsThe Derivo Embolization Device is a self-expanding stent consisting of 48 nitinol wires. The device was implanted across the necks of 17 elastase-induced aneurysms in New Zealand white rabbits. One additional device was implanted in the abdominal aorta of each animal covering the origin of lumbar arteries. Follow-up was performed after 3 months (n = 8) and 6 months (n = 9) under continuous double antiplatelet therapy. Statuses of angiographic and histological aneurysm occlusion as well as patency of branch arteries and neointimal growth were evaluated and compared with its prototype flow diverter.ResultsThe Derivo Embolization Device provided advanced visibility and flexibility, which led to more accurate navigation and placement. Complete aneurysm occlusion rates were noted in 15 cases (88 %), respectively, compared with 5 cases (28 %) with the first-generation device (p = 0.001). Neointimal growth and diameter stenosis were significantly less with the Derivo Embolization Device and declining after 6 months follow-up in the abdominal aorta. Extreme device oversizing led to distal occlusion of the parent vessel in three cases. Covered branch arteries remained patent throughout the entire period of observation.ConclusionsThe Derivo Embolization Device provides excellent occlusion of elastase-induced aneurysms while preserving branch arteries.

Neurocognitive status in patients with newly-diagnosed brain tumors in good neurological condition: The impact of tumor type, volume, and location

OBJECTIVE Neurocognitive function is of great importance in patients with brain tumors. Even patients in good neurological condition may suffer from neurocognitive dysfunction that affects their daily living. The purpose of the present study was to identify risk factors for neurocognitive dysfunction in patients suffering from common supratentorial brain tumors with minor neurological deficits. METHODS A prospective study evaluating neurocognitive dysfunction in patients with a newly-diagnosed brain tumor in good neurological condition was performed at a major German academic institution. Patients underwent extensive neurocognitive testing assessing perceptual speed, executive function, visual-spatial and verbal working memory, short- and long-term memory, verbal fluency, fluid intelligence, anxiety, and depression. For each patient, a healthy control was pair-matched based on age, sex, handedness, and profession. RESULTS A total of 46 patients and 46 healthy controls underwent neurocognitive testing. Patients suffered from glioblastoma multiforme (10), cerebral metastasis (10), pituitary adenoma (13), or meningioma (13). There was neither any difference in age, educational level, fluid intelligence, neurological deficits, and anxiety nor in any depression scores between tumor subgroups. Overall, neurocognitive performance was significantly worse in patients compared to healthy controls. Larger tumor volume, frontal location, and left/dominant hemisphere were associated with worse executive functioning and verbal fluency. Additionally, larger tumors and left/dominant location correlated with impairments on perceptual speed tasks. Frontal tumor location was related to worse performance in visual-spatial and short- and long-term memory. Tumor type, clinical presentation, and patient self-awareness were not associated with specific neurocognitive impairments. CONCLUSIONS Patients suffering from newly-diagnosed brain tumors presenting in good neurological condition display neurocognitive impairments in various domains. Larger tumor volumes, frontal location, and left/dominant hemisphere are important predictors for potential neurocognitive deficits. Tumor type, clinical presentation, or self-awareness are less significant at the time of diagnosis.

Preoperative navigated transcranial magnetic stimulation in patients with motor eloquent lesions with emphasis on metastasis

Navigated transcranial magnetic stimulation (nTMS) is a frequently used, non‐invasive method to map the motor cortex. It is of great value in the preoperative workup of patients that suffer from motor eloquent brain lesions. Here, we present a single‐center experience using preoperative nTMS in cortical motor eloquent lesions with emphasis on metastasis. All patients that underwent preoperative nTMS between June 2013 and January 2016 were evaluated. A total of 61 patients underwent nTMS before undergoing surgery for a motor eloquent brain lesion. Patients suffered from cerebral metastasis (23), glioblastoma (16), high grade glioma WHO III (4), low grade glioma WHO II (4), lymphoma (2), meningioma (8), cavernous hemangioma (3), or arteriovenous malformation (1). Thirty patients (49.2%) presented with a preoperative motor deficit. One week after surgery, paresis had resolved or improved in 56.7% of the patients. Out of the patients with postoperative paresis, 89.5% experienced an improvement of motor status at follow‐up. All metastatic lesions were completely resected compared to 78.9% of non‐metastatic lesions (P = 0.02). Only 4.3% of patients with a metastatic lesion, but 26.3% of patients with a non‐metastatic lesion experienced deterioration of motor function after surgery (P = 0.04). Preoperative nTMS is suitable for mapping of a variety of motor eloquent brain lesions resulting in favorable neurological outcome. Particularly in metastatic motor eloquent lesion, motor function appears to be preserved after surgery. Clin. Anat. 29:925–931, 2016.

Acute Occlusions of Dual-Layer Carotid Stents After Endovascular Emergency Treatment of Tandem Lesions

Background and Purpose— A new generation of carotid artery stents that uses a second micromesh layer to reduce embolic events during carotid artery stenting has recently been introduced. The purpose of this study was to compare acute occlusion rates of these new dual-layer stents with those of single-layer stents in the setting of emergency carotid artery stenting with intracranial mechanical thrombectomy in acute ischemic stroke. Methods— Consecutive patients with acute tandem (intra- and extracranial) lesions of the anterior circulation who were endovascularly treated at our institution were identified from our registry of neuroendovascular interventions. Clinical, angiographic, and neuroimaging data were analyzed. End points included acute occlusions of the carotid stents (within 72 hours after stenting) and symptomatic intracerebral hemorrhage. Results— Forty-seven patients were included. Dual-layer stents (n=20) had a significantly higher rate of acute occlusions than single-layer stents (n=27; 45% versus 3.7%; P=0.001; odds ratio, 21.3; 95% confidence interval, 2.4–188.4). There were no significant differences in the rates of patients who had any antiplatelet or dual antiplatelet medication before admission, in the rates of postinterventional symptomatic intracerebral hemorrhage, the mean National Institutes of Health Stroke Scale scores at admission, or the modified Rankin Scale scores at discharge. Conclusions— The recently introduced dual-layer stents have a higher risk of acute occlusion compared with single-layer stents in the treatment of acute stroke.

Cognitive function surrounding resection of nonfunctioning pituitary adenomas with suprasellar extension: A prospective matched-control study

OBJECTIVE Patients suffering from pituitary adenomas may experience cognitive dysfunctions due to hormonal imbalance or suprasellar tumor extension displacing neural structures. Progressively enlarging or symptomatic nonfunctioning pituitary adenomas with suprasellar extension are frequently resected. The literature on neurocognitive performance surrounding resection of these lesions is sparse. METHODS A prospective matched-control study was conducted to investigate the impact of nonfunctioning pituitary adenomas with suprasellar extension on preoperative and postoperative cognitive performance. Controls were matched for age, sex, handedness, education, and profession. The neurocognitive test battery included perceptual speed, executive function, visual-spatial and verbal working memory, short- and long-term memory, verbal fluency, fluid intelligence, anxiety, and depression. RESULTS Ten patients and 10 healthy controls were matched. Median suprasellar tumor extension scored 8mm, compression of frontal lobe parenchyma was present in all cases. Median sagittal tumor diameter was 21mm. Preoperatively, patients scored worse in perceptual speed and short-term memory tasks. All patients underwent surgical resection either through a transnasal, transsphenoidal approach or a supraorbital frontolateral keyhole approach. The short-term memory deficit disappeared one week after surgery. Perceptual speed recovered within two months after surgical therapy. None of the patients experienced worsening of cognitive function. Routine postoperative imaging at six months did not reveal displacement of neural structures or surgery-related complications in any of the patients. CONCLUSION Patients suffering from nonfunctioning pituitary adenomas with suprasellar extension may experience preoperative impairments in some neurocognitive domains that resolve within two months after surgery. The risk for cognitive deterioration with surgery appears to be low.

Preoperative navigated transcranial magnetic stimulation and tractography in transparietal approach to the trigone of the lateral ventricle

OBJECTIVE Eloquent neural structures including white matter tracts surround the trigone of the lateral ventricle. Surgical resection of trigonal tumors via the transparietal approach may cause neurological deterioration depending on the trajectory. METHODS The authors retrospectively reviewed patients with trigonal tumors that underwent combined preoperative navigated transcranial magnetic stimulation (nTMS) and optic radiation tractography to guide a transparietal approach towards the trigone. RESULTS Five patients underwent preoperative nTMS motor mapping, rTMS language mapping, nTMS-derived corticospinal tract tractography, and optic radiation tractography. The information was used to select the optimal trajectory for a transparietal approach and for intraoperative neuronavigation. Four patients underwent surgical resection. None of them experienced a new permanent deficit. CONCLUSION Combination of preoperative nTMS and optic radiation tractography facilitates the identification of the optimal parietal trajectory towards the trigone. It allows for sparing of visual and motor pathways as well as cortical language areas.

Preoperative Navigated Transcranial Magnetic Stimulation and Tractography to Guide Endoscopic Cystoventriculostomy: A Technical Note and Case Report

OBJECTIVE To report a technique for endoscopic cystoventriculostomy guided by preoperative navigated transcranial magnetic stimulation (nTMS) and tractography in a patient with a large speech eloquent arachnoid cyst. METHODS A 74-year old woman presented with a seizure and subsequent persistent anomic aphasia from a progressive left-sided parietal arachnoid cyst. An endoscopic cystoventriculostomy and endoscope-assisted ventricle catheter placement were performed. Surgery was guided by preoperative nTMS and tractography to avoid eloquent language, motor, and visual pathways. RESULTS Preoperative nTMS motor and language mapping were used to guide tractography of motor and language white matter tracts. The ideal locations of entry point and cystoventriculostomy as well as trajectory for stent-placement were determined preoperatively with a pseudo-3-dimensional model visualizing eloquent language, motor, and visual cortical and subcortical information. The early postoperative course was uneventful. At her 3-month follow-up visit, her language impairments had completely recovered. Additionally, magnetic resonance imaging demonstrated complete collapse of the arachnoid cyst. CONCLUSION The combination of nTMS and tractography supports the identification of a safe trajectory for cystoventriculostomy in eloquent arachnoid cysts.

Is there an impact of cervical plating on the development of adjacent segment degeneration following Smith-Robinson procedure? A magnetic resonance imaging study of 84 patients with a 24-year follow-up

BACKGROUND CONTEXT Anterior cervical discectomy and fusion (ACDF) without and with cervical plating (ACDF+CP) are accepted surgical techniques for the treatment of degenerative cervical disc disorders. The effect of CP on the development of adjacent segment degeneration (ASD) remains unclear. PURPOSE To assess whether CP accelerates the degeneration of the adjacent and adjoining segments. STUDY DESIGN/SETTING This is an imaging cohort study. PATIENT SAMPLE Retrospectively, a total of 84 patients who underwent ACDF or ACDF+CP were identified. At final follow-up, an MRI was performed and evaluated in this study. MATERIALS AND METHODS An MRI of 84 patients who underwent ACDF (46 patients) and ACDF+PS (38 patients) was performed. The mean follow-up was 24 years (17-45 years). None of the patients had a repeat procedure in the cervical spine. The grade of degeneration of the segments adjacent and adjoining to the fusion was assessed via a five-step grading system (segmental degeneration index, or SDI) that includes disc signal intensity, anterior and posterior disc protrusion, narrowing of the disc space, and foraminal stenosis. Furthermore, the disc height (DH) and sagittal segmental angle (SSA) of fused segments were measured. RESULTS A significantly (p<.001) greater SDI was identified at the caudal adjacent segment following ACDF compared to ACDF+CP. No other significant differences were identified in patients following ACDF and ACDF+CP. Between 50% and 96% of all segments showed severe degenerative changes according to SDI. There was no significant difference in DH between the patients following ACDF and ACDF+CP. The SSA in patients who underwent ACDF+CP was significantly greater than in the ACDF patients (p=.002). CONCLUSIONS In this cohort of patients, cervical plating had no significant impact on segmental degeneration and decrease of DH in the adjacent and adjoining segments. ACDF+CP seem to preserve the lordotic alignment more with respect to the SSA than ACDF.

Adjacent Segment Degeneration After Anterior Cervical Discectomy and Fusion With an Autologous Iliac Crest Graft: A Magnetic Resonance Imaging Study of 59 Patients With a Mean Follow-up of 27 Years

BACKGROUND Anterior cervical decompression and fusion (ACDF) is a widely accepted surgical technique for the treatment of degenerative disc disease. ACDF is associated with adjacent segment degeneration (ASD). OBJECTIVE To assess whether physiological aging of the spine would overcome ASD by comparing adjacent to adjoining segments more than 18 yr after ACDF. METHODS Magnetic resonance imaging of 59 (36 male, 23 female) patients who underwent ACDF was performed to assess degeneration. The mean follow‐up was 27 yr (18‐45 yr). Besides measuring the disc height, a 5‐step grading system (segmental degeneration index [SDI]) including disc signal intensity, anterior and posterior disc protrusion, narrowing of the disc space, and foraminal stenosis was used to assess the grade of adjacent and adjoining segments. RESULTS The SDI of cranial and caudal adjacent segments was significantly higher compared to adjoining segments (P < .001). The disc height of cranial and caudal adjacent segments was significantly lower compared to adjoining segments (P < .001, P < .01). The SDI of adjacent segments in patients with repeat cervical procedure was significantly higher than in patients without repeat procedure (P = .02, P = .01). The disc height of the cranial adjacent segments in patients with repeat procedure was significantly lower than in patients without repeat procedure (P = .01). CONCLUSION The physiological aging of the cervical spine does not overcome ASD. The disc height and the SDI in adjacent segment are significantly worse compared to adjoining segments. Patients who underwent repeat procedure had even worse findings of disc height and SDI.