Publications by authors named "Ibrahim Erol Sandalcioglu"

20 Publications

  • Page 1 of 1

VICTORIA: VIrtual neck Curve and True Ostium Reconstruction of Intracranial Aneurysms.

Cardiovasc Eng Technol 2021 08 7;12(4):454-465. Epub 2021 Jun 7.

Department of Simulation and Graphics, University of Magdeburg, Magdeburg, Germany.

Purpose: For the status evaluation of intracranial aneurysms (IAs), morphological and hemodynamic parameters can provide valuable information. For their extraction, a separation of the aneurysm sac from its parent vessel is required that yields the neck curve and the ostium. However, manual and subjective neck curve and ostium definitions might lead to inaccurate IA assessments.

Methods: The research project VICTORIA was initiated, allowing users to interactively define the neck curve of five segmented IA models using a web application. The submitted results were qualitatively and quantitatively compared to identify the minimum, median and maximum aneurysm surface area. Finally, image-based blood flow simulations were carried out to assess the effect of variable neck curve definitions on relevant flow- and shear-related parameters.

Results: In total, 55 participants (20 physicians) from 18 countries participated in VICTORIA. For relatively simple aneurysms, a good agreement with respect to the neck curve definition was found. However, differences among the participants increased with increasing complexity of the aneurysm. Furthermore, it was observed that the majority of participants excluded any small arteries occurring in the vicinity of an aneurysm. This can lead to non-negligible deviations among the flow- and shear-related parameters, which need to be carefully evaluated, if quantitative analysis is desired. Finally, no differences between participants with medical and non-medical background could be observed.

Conclusions: VICTORIAs findings reveal the complexity of aneurysm neck curve definition, especially for bifurcation aneurysms. Standardization appears to be mandatory for future sac-vessel-separations. For hemodynamic simulations a careful neck curve definition is crucial to avoid inaccuracies during the quantitative flow analysis.
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http://dx.doi.org/10.1007/s13239-021-00535-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8354974PMC
August 2021

Dynein Light Chain Protein Tctex1: A Novel Prognostic Marker and Molecular Mediator in Glioblastoma.

Cancers (Basel) 2021 May 27;13(11). Epub 2021 May 27.

Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf (UKE), 20246 Hamburg, Germany.

The purpose of this study was to determine the role of Tctex1 (DYNLT1, dynein light chain-1) in the pathophysiology of glioblastoma (GBM). To this end, we performed immunohistochemical analyses on tissues from GBM patients ( = 202). Tctex1 was additionally overexpressed in two different GBM cell lines, which were then evaluated in regard to their proliferative and invasive properties. We found that Tctex1 levels were significantly higher in GBM compared to healthy adjacent brain tissues. Furthermore, high Tctex1 expression was significantly associated with the short overall- ( = 0.002, log-rank) and progression-free ( = 0.028, log-rank) survival of GBM patients and was an independent predictor of poor overall survival in multivariate Cox-regression models. In vitro, Tctex1 promoted the metabolic activity, anchorage-independent growth and proliferation of GBM cells. This phenomenon was previously shown to occur via the phosphorylation of retinoblastoma protein (phospho-RB). Here, we found a direct and significant correlation between the levels of Tctex1 and phospho-RB (Ser807/801) in tissues from GBM patients ( = 0.007, Rho = 0.284, Spearman's rank). Finally, Tctex1 enhanced the invasiveness of GBM cells and the release of pro-invasive matrix metalloprotease 2 (MMP2). These findings indicate that Tctex1 promotes GBM progression and therefore might be a useful therapeutic target in this type of cancer.
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http://dx.doi.org/10.3390/cancers13112624DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8199143PMC
May 2021

KLF4-mutated meningiomas show enhanced hypoxia signaling and respond to mTORC1 inhibitor treatment.

Acta Neuropathol Commun 2020 04 3;8(1):41. Epub 2020 Apr 3.

Department of Neuropathology, Otto-von-Guericke University, Magdeburg, Germany.

Meningioma represents the most common primary brain tumor in adults. Recently several non-NF2 mutations in meningioma have been identified and correlated with certain pathological subtypes, locations and clinical observations. Alterations of cellular pathways due to these mutations, however, have largely remained elusive. Here we report that the Krueppel like factor 4 (KLF4)-K409Q mutation in skull base meningiomas triggers a distinct tumor phenotype. Transcriptomic analysis of 17 meningioma samples revealed that KLF4 mutated tumors harbor an upregulation of hypoxia dependent pathways. Detailed in vitro investigation further showed that the KLF4 mutation induces HIF-1α through the reduction of prolyl hydroxylase activity and causes an upregulation of downstream HIF-1α targets. Finally, we demonstrate that KLF4 mutated tumors are susceptible to mTOR inhibition by Temsirolimus. Taken together, our data link the KLF4 mediated upregulation of HIF pathways to the clinical and biological characteristics of these skull base meningiomas possibly opening new therapeutic avenues for this distinct meningioma subtype.
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http://dx.doi.org/10.1186/s40478-020-00912-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7118946PMC
April 2020

First visualization of the human subarachnoid space and brain cortex optical coherence tomography.

Ther Adv Neurol Disord 2019 11;12:1756286419843040. Epub 2019 Apr 11.

Department of Neurosurgery, KRH Klinikum Nordstadt, Hanover, Germany.

The present work explores optical coherence tomography (OCT) as a suitable neuroimaging modality of the subarachnoid space (SAS). Patients ( = 26) with frontolateral craniotomy were recruited. The temporal and frontal arachnoid mater and adjacent anatomical structures were scanned using microscope-integrated three-dimensional OCT, (iOCT). Analysis revealed a detailed depiction of the SAS (76.9%) with delineation of the internal microanatomical structures such as the arachnoid barrier cell membrane (ABCM; 96.2%), trabecular system (50.2%), internal blood vessels (96.2%), pia mater (26.9%) and the brain cortex (96.2%). Orthogonal distance measuring was possible. The SAS showed a mean depth of 570 µm frontotemporal. The ABCM showed a mean depth of 74 µm frontotemporal. These results indicate that OCT provides a dynamic, non-invasive tool for real-time imaging of the SAS and adjacent anatomical structures at micrometer spatial resolution. Further studies are necessary to evaluate the value of OCT during microsurgical procedures.
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http://dx.doi.org/10.1177/1756286419843040DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6689907PMC
April 2019

Sex-specific clinicopathological significance of novel (Frizzled-7) and established (MGMT, IDH1) biomarkers in glioblastoma.

Oncotarget 2016 Aug;7(34):55169-55180

Department of Neurosurgery, Nordstadt Hospital Hannover, Hannover, Germany.

Background: The Wnt receptor Frizzled-7 (FZD7) promotes tumor progression and can be currently targeted by monoclonal antibody therapy. Here, we determined the prognostic value of FZD7 for the overall survival of glioblastoma (GBM) patients, both as individual marker and taken in combination with the previously-described markers MGMT and IDH1. Additionally, we tested whether these markers (alone or in combination) exhibited sex-specific differences.

Results: High levels of FZD7 (FZD7high) associated with shorter survival in GBM patients; however, FZD7high was a significant predictor of poor survival only in male patients. Mutation of IDH1 significantly associated with longer survival in male but not female patients. Methylated MGMT promoter significantly associated with longer survival only in female patients. Combination of FZD7 with MGMT enhanced the prognostic accuracy and abrogated the sex differences observed upon single marker analysis. Combination of FZD7 with IDH1 was a significant predictor of survival in male GBM patients only.

Materials And Methods: Three independent cohorts of patients with primary GBM (n=120, n=108 and n=105, respectively) were included in this study. FZD7 and IDH1 were assessed by immunohistochemistry in tissue microarrays. MGMT promoter methylation was determined by methylation-specific polymerase chain reaction. Survival analysis was performed by Kaplan-Meier estimate, log-rank test and Cox proportional hazard regression.

Conclusions: Our study identifies novel individual and combination markers with prognostic and, possibly, therapeutic relevance in GBM. Furthermore, our findings substantiate the importance of sexual dimorphism in this type of cancer.
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http://dx.doi.org/10.18632/oncotarget.10465DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5342409PMC
August 2016

Associated Aneurysms in Infratentorial Arteriovenous Malformations: Role of Aneurysm Size and Comparison with Supratentorial Lesions.

Cerebrovasc Dis 2016 22;41(5-6):219-25. Epub 2016 Jan 22.

Department of Neurosurgery, University Hospital Essen, University Duisburg-Essen, Essen, Germany.

Background: The natural history and treatment of brain arteriovenous malformations (AVMs) is the object of ongoing debates and discussions. To capture the entirety of these complex lesions, associated vascular pathologies, such as associated aneurysms (AAs), have to be implemented in future risk stratification models, as they are believed to represent additional risk factors for intracranial hemorrhage. The present study aims to determine AA characteristics in posterior fossa AVMs and to compare with AAs accompanying supratentorial AVMs, with special focus on aneurysm size.

Methods: Patients with cerebral AVMs, treated in our department between 1990 and 2013, were analyzed retrospectively. Only patients with flow-related AAs of the feeding arteries were evaluated. Thus, patients harboring intranidal, venous or remote aneurysms were excluded.

Results: Of 485 patients with cerebral AVM, 76 patients harbored an AVM of the posterior fossa. Among those, 22 individuals exhibited a total of 35 AAs (n = 8 patients with multiple AAs). Most common location of AAs was the posterior inferior cerebellar artery (n = 20, 57%) and mean AA diameter was 7.9 mm (SD 5.5). In the subgroup of patients with a single AA, mean aneurysm size in posterior fossa AVMs was with 7.8 mm (SD 6.0; range 2-25 mm) significantly larger than the mean size of AAs with supratentorial AVMs (4.8 mm, SD 3.0; range 2-20 mm; p = 0.048). Intracranial hemorrhage was found in 18 of 22 patients (82%) with infratentorial AVMs, and of these, 11 patients suffered from aneurysm rupture. In 14 patients bearing a single AA, 8 (57%) had sustained hemorrhage from aneurysm rupture. The mean diameter of AAs was as supposed in the ruptured group with 9.8 mm (SD 6.9; range 4-25 mm) significantly larger than in the unruptured AA group exhibiting a mean of 5.0 mm (SD 3.3; range 2-10 mm; p = 0.038). Patients with posterior fossa AVMs and AAs were significantly older as compared to those patients with supratentorial lesions (57.1, SD 12.6 vs. 45.8 years, SD 15.9 years; p = 0.004), which was also evident in the subgroup of patients with single AAs (55.2, SD 11.7 vs. 45.8 years, SD 14.9 years; p = 0.038).

Conclusions: AAs of posterior fossa AVMs are larger in diameter than aneurysms accompanying supratentorial AVMs. AA size influences risk for hemorrhage, which, together with the high number of hemorrhagic events in posterior fossa AVMs, justifies treating these pathologies. The higher age of patients with AVMs of the posterior fossa might be one reason for larger AAs in this cohort, when compared to patients with supratentorial AVMs and AAs.
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http://dx.doi.org/10.1159/000443540DOI Listing
November 2017

A retrospective and consecutive analysis of the epidemiology and management of spinal cavernomas over the last 20 years in a single center.

Neurosurg Rev 2016 Apr 2;39(2):269-76; discussion 276. Epub 2015 Dec 2.

Department of Neurosurgery, University Hospital Essen, University Duisburg-Essen, Hufelandstrasse 55, 45122, Essen, Germany.

Spinal cavernous malformations (SCM) are rare lesions often presenting with acute onset of symptoms and progressive neurological deterioration due to hemorrhage into the spinal cord. With the aid of modern techniques, their surgical removal became much safer. The present study was undertaken to analyze the outcome of our series of surgically and conservatively treated patients with SCM. Over a period of 20 years, 20 surgically treated and 5 conservatively managed patients with spinal cavernous malformations were identified and enrolled into this analysis. Demographic data, clinical symptoms, localization and extension of the cavernoma, as well as pre- and postoperative neurological status were obtained. The clinical status was assessed using the Frankel score. Patients were followed up clinically and by MRI. Before surgery, 90% (18/20) of our surgical patients were classified as Frankel D (93.8%), whereas two patients (10%) were graded C. None of the patients had a worse Frankel score at the time of discharge. Eighty percent of them (16 cases) remained unchanged, and 20% (4 patients) improved during the first follow-up (mean 6.3 months, range 2-17 months). All improved patients had a superficially located SCM and were operated early (≤3 months). No worsening was observed during extended follow-up (range 9-134 months, mean 44.7 months). Five nonsurgically treated patients showed no significant clinical deterioration over a period of 6.7 years (mean, range 2.9-8 years). SCM localization and number of involved segments had no influence on outcome. Our data show that SCM can be resected with favorable neurological outcome by using intraoperative neuromonitoring. Within the follow-up period, patients treated conservatively remained in a stable neurological condition.
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http://dx.doi.org/10.1007/s10143-015-0674-7DOI Listing
April 2016

Single center experience with treatment of spinal dural arteriovenous fistulas.

Neurosurg Rev 2015 Oct 17;38(4):683-92. Epub 2015 Jul 17.

Department of Neurosurgery, University Hospital of Essen, Hufelandstrasse 55, 45122, Essen, Germany,

Spinal dural arteriovenous fistulas (SDAVFs) are rare pathologies with a yearly incidence of 5-10 new cases/million, constituting 60-80 % of spinal arteriovenous malformations. Clinical symptoms include progressive paraparesis, paresthesias, bladder, and bowel disturbances. The pathophysiology of SDAVFs is not well elucidated. Microneurosurgery and endovascular techniques are established treatment modalities for permanent fistula occlusion, which are oftentimes accompanied by an amelioration of neurological deficits in the long run. Here, we report our interdisciplinary neurosurgical/neuroradiological management strategy of SDAVFs in 32 patients who were evaluated retrospectively. We focused on clinical presentation, microneurosurgical and interventional technique, early, and late neurological results. Quality of life (QoL) was additionally assessed in 12 patients at last follow-up. We discuss the results against the background of the current literature. Our series and the literature indicate that clinical outcome after treatment of SDAVF is favorable in general. Both neurosurgical and neurointerventional therapies appear to be safe and effective, but short-term neurological deterioration after the intervention constitutes an as-of-yet unsolved problem. Beyond age and preoperative neurological state, presence of comorbidities had a significant influence on neurological outcome in our study sample. Self-assessed physical and mental QoL at long-term follow-up was reduced in quite a number of patients and was associated with a poorer neurological result as well as presence of comorbidities. The patients' perspective in terms of QoL was first investigated in this study, but further research on QoL and psychosocial impairment of SDAVF patients is needed to enable individualized counseling and rehabilitation strategies.
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http://dx.doi.org/10.1007/s10143-015-0645-zDOI Listing
October 2015

Intramedullary spinal cord astrocytomas: the influence of localization and tumor extension on resectability and functional outcome.

Acta Neurochir (Wien) 2013 Jul 23;155(7):1203-7. Epub 2013 May 23.

Department of Neurosurgery, University Hospital Essen, University Duisburg-Essen, Essen, Germany.

Background: Intramedullary spinal cord tumors (IMSCT) are rare lesions, ependymomas and astrocytomas being the most common ones. Different studies have been published showing results of different treatment strategies as extensive/ limited surgery, biopsy and adjuvant radiation therapy with regard to functional outcome and survival. The present study was undertaken to analyse our series of surgically treated intramedullary astrocytomas in order to identify factors with impact on functional outcome and resectability.

Methods: Over a period of 20 years, among 215 patients with IMSCT 22 patients with astrocytomas were identified and enrolled into this analysis. Demographic data, clinical symptoms, localization and extension of the tumor, resection rate as well as pre- and postoperative neurological status were obtained. Patients were followed-up clinically and by MRI.

Results: Complete resection rate was higher in cervically located tumors (9 of 10) compared to non-cervical tumors (7 of 12). Tumor extension (1-3 segments vs. > 3 segments involved) did not influence on the resection rate. Cervical tumors showed a trend for better postoperative functional outcome than non-cervical lesions (3 of 10 cervical but 6 of 12 non-cervical tumors deteriorated postoperatively). In tumors extending more than 3 segments postoperative worsening was significantly increased.

Conclusions: The present study shows a better resectability and functional outcome for cervically located intramedullary astrocytomas. Tumors extending more than three segments deteriorated significantly. These findings may help for decision-making process and treatment of these tumors.
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http://dx.doi.org/10.1007/s00701-013-1762-5DOI Listing
July 2013

Intracerebral metastases of malignant melanoma and their recurrences--a clinical analysis.

Clin Neurol Neurosurg 2013 Sep 1;115(9):1721-8. Epub 2013 May 1.

Department of Neurosurgery, University Hospital Essen, Essen, Germany.

Introduction: Brain metastases (BM) commonly occur in patients with metastatic malignant melanoma (MM). Prognosis is poor even with maximal therapy. The aim of the current study was to retrospectively evaluate patients with BM of MM who were treated neurosurgically with respect to clinical presentation, recurrent disease, survival and factors affecting survival.

Patients And Methods: Thirty-four patients (19f/15m) with BM of MM were treated in our hospital between 2000 and 2010. Patient data were analysed, survival was examined using Kaplan-Meier-estimates and factors affecting prognosis were evaluated using uni- and multivariate analysis.

Results: Twenty-two patients (64.7%) had a single BM, whereas twelve patients (35.3%) revealed two or more lesions. Median survival for patients with a single BM was 13.0 months (95%-CI 9.3-16.7 months), this was significantly (p=0.014) better than for patients with two or more BM (median 5.0, 95%-CI 3.4-14.6 months). Nineteen patients (55.9%) developed an intracranial relapse after microsurgical resection of a first lesion. Patients with an isolated intracerebral relapse survived significantly (p=0.003) longer than those with systemic progression (median 6.0, 95%-CI 0.0-15.3 months vs median 3.0, 95%-CI 1.7-4.3 months). Similarly, patients with a high performance status showed significantly (p=0.001) prolonged survival (median 7.0, 95%-CI 0.0-19.9 months vs median 1.0, 95%-CI 0.0-2.2 months). Eleven out of nineteen patients (57.9%) underwent either another microsurgical resection (n=6) or stereotactic radiosurgery (n=5). These patients remained on a high performance status even after aggressive therapy.

Discussion: Even though the prognosis for patients with BM of MM is generally poor, patients with a single BM can benefit from microsurgical resection. However, there is a high risk of intracranial relapse. In selected patients with a good performance status and recurrent intracranial disease, recurrent local therapy can be justified and useful.
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http://dx.doi.org/10.1016/j.clineuro.2013.03.019DOI Listing
September 2013

Loss of CCM3 impairs DLL4-Notch signalling: implication in endothelial angiogenesis and in inherited cerebral cavernous malformations.

J Cell Mol Med 2013 Mar 7;17(3):407-18. Epub 2013 Feb 7.

Department of Neurosurgery, University of Duisburg-Essen, Essen, Germany.

CCM3, a product of the cerebral cavernous malformation 3 or programmed cell death 10 gene (CCM3/PDCD10), is broadly expressed throughout development in both vertebrates and invertebrates. Increasing evidence indicates a crucial role of CCM3 in vascular development and in regulation of angiogenesis and apoptosis. Furthermore, loss of CCM3 causes inherited (familial) cerebral cavernous malformation (CCM), a common brain vascular anomaly involving aberrant angiogenesis. This study focused on signalling pathways underlying the angiogenic functions of CCM3. Silencing CCM3 by siRNA stimulated endothelial proliferation, migration and sprouting accompanied by significant downregulation of the core components of Notch signalling including DLL4, Notch4, HEY2 and HES1 and by activation of VEGF and Erk pathways. Treatment with recombinant DLL4 (rhDLL4) restored DLL4 expression and reversed CCM3-silence-mediated impairment of Notch signalling and reduced the ratio of VEGF-R2 to VEGF-R1 expression. Importantly, restoration of DLL4-Notch signalling entirely rescued the hyper-angiogenic phenotype induced by CCM3 silence. A concomitant loss of CCM3 and the core components of DLL4-Notch signalling were also demonstrated in CCM3-deficient endothelial cells derived from human CCM lesions (CCMEC) and in a CCM3 germline mutation carrier. This study defined DLL4 as a key downstream target of CCM3 in endothelial cells. CCM3/DLL4-Notch pathway serves as an important signalling for endothelial angiogenesis and is potentially implicated in the pathomechanism of human CCMs.
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http://dx.doi.org/10.1111/jcmm.12022DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3823022PMC
March 2013

Minimally invasive transpedicular dorsal stabilization of the thoracolumbar and lumbar spine using the minimal access non-traumatic insertion system (MANTIS): preliminary clinical results in 52 patients.

J Neurol Surg A Cent Eur Neurosurg 2012 Nov 13;73(6):369-76. Epub 2012 Jun 13.

Department of Neurosurgery, University Hospital Essen, Essen, Germany.

Background: The aim of this study is to report about a preliminary experience with a new minimally invasive percutaneous transpedicular dorsal stabilization system (MANTIS, Stryker, Kalamazoo, MI, USA) for thoracolumbar and lumbar spinal diseases to demonstrate the benefits of the operative technique and drawbacks.

Material And Methods: The minimally invasive percutaneous transpedicular stabilization technique was performed in 52 patients with thoracolumbar and lumbar spinal diseases from February 2009 to August 2010. The average age of 25 male and 27 female patients was 60 years (range 15 to 81 years). Visual analog scale (VAS) was used for pre- and postoperative evaluation of pain. In all patients, preoperative magnetic resonance imaging and computed tomography (CT) scan were performed to evaluate the neuronal and bony structures. Screw position of all operated segments was controlled by postoperative CT scan.

Results: Indication for surgery was spondylolisthesis in 28 cases (53.8%), vertebral fracture in 15 cases (28.8%), vertebral metastasis in 8 patients (15.4%), and spondylodiscitis in 1 patient (1.9%). Decompressive laminectomy was performed in 37 cases (71.2%). An additional interbody fusion was necessary in 26 patients (50%) due to degenerative motion spondylolisthesis. All patients showed pain improvement after surgery. The average preoperative VAS score was 7.98 (minimum 5 and maximum 10) and improved after surgery to 2.15 (minimum 0 and maximum 8). The rate of screw misplacement was 4.62% (10 of 216 screws). We revised three screws (1.38%) in three different patients (5.6%) due to suboptimal screw position although these patients had no neurological deterioration. Postoperative complications include cerebrospinal fluid leakage in four cases (7.7%), which occurred during the decompressive procedure. One patient showed a postoperative hematoma located in the paravertebral muscle.

Conclusion: Minimally invasive transpedicular screw stabilization systems such as the MANTIS lead to safe and effective procedures. They can be used for different spinal disorders and can be combined with additional surgical procedures such as intervertebral fusion or decompression, if necessary.
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http://dx.doi.org/10.1055/s-0032-1304816DOI Listing
November 2012

AVM resection after radiation therapy--clinico-morphological features and microsurgical results.

Neurosurg Rev 2010 Jan;33(1):53-61

Department of Neurosurgery, University Hospital Essen, Hufelandstr. 55, 45147 Essen, Germany.

A subgroup of patients initially treated by radiosurgery underwent surgical resection because of recurrent hemorrhage or neurological deterioration. In a retrospective study, we want to analyze the clinical features of these patients and evaluate the effect of microneurosurgery in such rare constellations. Moreover, we hope to find answers about failure of radiation therapy in these cases by correlation of radiobiological and histopathological data. Over a 16-year-period, eight patients with cerebral arteriovenous malformation (AVM) underwent surgical resection, who previously were treated by radiosurgery. The mean duration between radiation therapy and final resection was 7 years. Preoperative evaluation revealed Spetzler-Martin grade III (n=5) and IV (n=3) AVMs. Histological examination was achieved in all resected lesions. Mean neurological follow-up was 14 months. Indications for surgical resection were intracerebral hematoma, progressive neurological deficit, and epilepsy. In comparison to the initial angiographic study before radiation therapy, preoperative angiography revealed newly developed "en passant" feeding vessels and stenosis of the main venous drainage in some patients. The mean Rankin score for all patients was 2.75 before and 3.25 after surgical resection. Postoperatively, three patients (38%) developed neurological deterioration. Histological examination of the resected tissue revealed significant radiation-induced pathology in six patients. We did not see correlation between radiation doses and severity of histolopathological radiation-induced changes. Postoperative angiography confirmed total AVM resection in all patients. AVMs insufficiently treated by radiation bear an increased surgical risk. Often, angiographic studies revealed a more complicated morphology. Microsurgical resection was extremely challenging and led to unfavorable outcomes in many of the patients.
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http://dx.doi.org/10.1007/s10143-009-0216-2DOI Listing
January 2010

Fusion of the cerebellar hemispheres ventral to the brainstem: a rare hindbrain-related malformation.

Childs Nerv Syst 2006 Jan 23;22(1):73-7. Epub 2004 Dec 23.

Department of Neurosurgery, University of Essen, Hufelandstrasse 55, 45122 Essen, Germany.

Introduction: New variations of cerebellar malformations are being increasingly recognized using modern neuroimaging techniques. Until now only dorsal cerebellar fusion syndromes, such as the rhombencephalosynapsis and its variations have been recognized.

Case Report: We report on a 17-month-old male infant presenting with an exceptional hindbrain related malformation characterized by midline fusion of the cerebellar hemispheres ventral to the brainstem and causing symptoms due to brainstem compression.

Discussion And Conclusion: A more detailed understanding of the cerebellar embryogenesis is required to unravel the underlying mechanisms leading to this type of cerebellar malformation, which cannot easily be integrated into the common classification systems. Both the morphological features and the clinical presentation are different from those of other cerebellar structural abnormalities. If this type of congenital malformation is detected more frequently in the future, it seems reasonable that it should be added to the list of cerebellar malformations as a distinct type.
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http://dx.doi.org/10.1007/s00381-004-1065-5DOI Listing
January 2006

Reconstruction of the laminar roof with miniplates for a posterior approach in intraspinal surgery: technical considerations and critical evaluation of follow-up results.

Spine (Phila Pa 1976) 2004 Aug;29(16):E333-42

Neurochirurgische Klinik und Poliklinik, Universitätsklinikum Essen (UKE), and the Department of Neurosurgery, University of Essen, Essen, Germany.

Study Design: A retrospective clinical follow-up study of patients who underwent intraspinal surgery with reconstruction of the laminar roof using titanium miniplates.

Objective: To evaluate the surgical technique of laminar roof reconstruction and to analyze follow-up results with regard to bony healing of the laminae and the development of spinal deformities.

Summary And Background Data: The reconstruction of the laminar roof was initially proposed to overcome adverse effects associated with extensive cervical laminectomy in children. Because technical evolutions such as the use of an air drill and miniplates have facilitated the procedure, it has gained more widespread use as a posterior approach for intraspinal surgery. Thus, with a sufficient number of patients treated and a longer period of follow up, it seems reasonable to critically evaluate the technique and its suitability as a standard approach for intraspinal surgery.

Methods: The surgical procedures of 79 patient who underwent intraspinal surgery with osteotomy and reconstruction of a total of 323 spinal laminae using an air drill and miniplates were analyzed. In 59 patients, data of a complete clinical and radiologic follow-up examination were evaluated. Plain radiographs and computed tomography scans were analyzed for bony healing of the laminae and spinal alignment.

Results: Minor complications such as cerebrospinal fluid collections and disturbed wound healing occurred within normal ranges. The was no case of dural, nerve root, or spinal cord injury attributable to laminotomy or laminar reconstruction. Eight (14.3%) patients complained of moderate to severe local pain at the time of follow-up examination and 8 patients stated impaired mobility of their spine at the surgical site. Bony healing was confirmed radiologically in 86.1% of the laminae. In 12 patients, a preexisting spinal deformity worsened after surgery and five patients demonstrated a new spinal malalignment. No patient required additional surgery because of progressive spinal deformity. Intramedullary location of the lesion and cervical location of surgery were significantly associated with the development of spinal malalignment, whereas incomplete bony healing of the laminae was not.

Conclusions: The reconstruction of the laminar roof using the technique described is safe, well suitable to serve as a standard posterior approach to intraspinal pathologies, and offers distinct advantages over laminectomy. However, some patients, particularly those with intramedullary cervical lesions, could develop spinal malalignment after surgery despite reconstruction of the laminar roof and sufficient bony healing of the laminae.
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http://dx.doi.org/10.1097/01.brs.0000134592.07941.5eDOI Listing
August 2004

Enhanced stability of somatosensory evoked potentials attained in the median nerve by using temporal electrodes for intraoperative recording in patients in the semisitting position.

J Neurosurg 2003 Dec;99(6):986-90

Neurochirurgische Klinik, Universitätsklinikum Essen, Germany.

Object: Findings published in case reports indicate that monitoring of median nerve somatosensory evoked potentials (MN-SSEPs) is unreliable in patients who undergo surgery while in the semisitting position due to the occurrence of changes in the potentials that are unrelated to neurological damage. The present study was designed to test the hypothesis that in these patients MN-SSEPs are more stable when recording electrodes are placed over the temporal region.

Methods: In 30 patients who underwent surgery in the semisitting position, MN-SSEPs were recorded intraoperatively by using electrodes placed over the temporal region as well as those placed at conventional recording sites. The authors analyzed MN-SSEP amplitudes and latencies at different recording sites and at distinct steps of the monitoring procedure. In 10 of the 30 patients a clinically significant attenuation (> 50%) of MN-SSEP amplitude was observed at conventional recording sites and this was obviously not related to neurological damage. In contrast, no significant changes were observed in MN-SSEPs recorded from electrodes located over the temporal region.

Conclusions: In patients who undergo surgery in the semisitting position, the use of additional recording electrodes placed over the temporal region makes intraoperative MN-SSEP monitoring less prone to false-positive alarms and thus enhances the reliability of intraoperative MN-SSEP monitoring.
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http://dx.doi.org/10.3171/jns.2003.99.6.0986DOI Listing
December 2003

Transcortical or transcallosal approach to ventricle-associated lesions: a clinical study on the prognostic role of surgical approach.

Neurosurg Rev 2003 Jul 22;26(3):192-7. Epub 2002 Aug 22.

Department of Neurosurgery, University Hospital of Essen, Hufelandstrasse 55, 45147 Essen, Germany.

Most entities in and around the anterior two-thirds of the supratentorial ventricles can be reached via transcortical or transcallosal approach. This study examined the effect of surgical approach on the postoperative neurological outcome. Thirty-eight patients with intra- and periventricular supratentorial lesions were operated on by either frontal transcortical or anterior transcallosal approach. Postoperative diencephalic damage occurred in 22% of patients in the transcortical group and in 36% in the transcallosal group; transient mutism was virtually equivalent in the two groups. Postoperative epilepsy (26%) and subdural fluid collections (30%) occurred only in the transcortical group. The incidence of postoperative hemiparesis was higher in the transcallosal group. There was a high correlation between postoperative Glasgow Outcome Score of 5 and preoperative severity of neurological disease but no correlation between postoperative Glasgow Outcome Score of 5 and location of the lesion or between postoperative clinical course and surgical approach. Surgical outcome of ventricle-associated lesions depends mainly on the severity of preoperative symptoms and not on surgical approach. Additionally, the incidence of postoperative seizures and subdural fluid collections after transcortical surgery is high.
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http://dx.doi.org/10.1007/s10143-002-0239-4DOI Listing
July 2003

Intramedullary spinal cord cavernous malformations: clinical features and risk of hemorrhage.

Neurosurg Rev 2003 Oct 1;26(4):253-6. Epub 2003 Apr 1.

Department of Neurosurgery, University of Essen, Hufelandstrasse 55, 45122 Essen, Germany.

The aim of this study was to review the natural history of symptomatic intramedullary spinal cord (IMSC) cavernous malformations in order to analyze the underlying mechanisms leading to symptoms and determine the potential risk of lesional hemorrhage. Between January 1990 and June 2001, ten consecutive patients with IMSC cavernous malformations were treated surgically in our institution. Age ranged from 17 to 73 years (mean 34.5). All patients became symptomatic due to one or more hemorrhages leading to neurological deficits of different severity, with a more aggressive course for upper cervical lesions. Pre- and postoperative patient condition was classified according to the Frankel scale. Four patients experienced one hemorrhage, four patients two, one patient three, and another one five repeated hemorrhages. The annual retrospective hemorrhage rate for symptomatic IMSC cavernous malformations was 4.5% per patient/year, with a prospective rehemorrhage risk of 66% per patient/year. The postoperative condition was improved in four patients and unchanged in six, and none grew worse. Detailed analysis of history and clinical course in all patients revealed an acute onset of symptoms with subsequent neurological deterioration after each bleeding episode. Based on the significant risk of rehemorrhage and the gratifying functional results, surgery is indicated for symptomatic IMSC cavernous malformations.
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http://dx.doi.org/10.1007/s10143-003-0260-2DOI Listing
October 2003

Favourable outcome after biopsy and decompression of a holocord intramedullary spinal cord astrocytoma in a newborn.

Eur J Paediatr Neurol 2002 ;6(3):179-82

Department of Neurosurgery, University of Essen, Germany.

A 4-month-old male infant presented with hydrocephalus as the initial clinical symptom due to a holocord intramedullary low-grade astrocytoma. This case illustrates a possible alternative treatment to radical surgery with a benign long-term course over a 4.5 year follow-up period.
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http://dx.doi.org/10.1053/ejpn.2002.0587DOI Listing
February 2003

The impact of neurophysiological intraoperative monitoring on surgical decisions: a critical analysis of 423 cases.

J Neurosurg 2002 Feb;96(2):255-62

Department of Neurosurgery, University of Essen Medical School, Germany.

Object: The aim of this observational clinical study was to analyze the impact of neurophysiological intraoperative monitoring (IOM) on the surgical procedure and to assess the benefits of such monitoring.

Methods: Data for 423 patients who underwent neurophysiological IOM with somatosensory evoked potentials and brainstem auditory evoked potentials during neurosurgical procedures were collected prospectively. The patients were classified into one of five groups according to the findings of IOM, the intervention following a monitoring alarm, and the patient's postoperative neurological condition. These groups were as follows: patients with true-positive findings with intervention (42 cases, 9.9%), those with true-positive findings without intervention (42 cases, 9.9%), those with false-positive findings (nine cases, 2.1%), those with false-negative findings (16 cases, 3.8%), and those with true-negative findings (314 cases, 74.2%). Different interventions followed an event identified with monitoring. These interventions were related to dissection in 17 cases, to perfusion pressure in 11, to a limitation of the surgical procedure in five, to vessel clipping in four, to vasospasm in three, and to retraction in one case. In one case the surgical procedure was abandoned. A critical analysis and cautious estimation of the interventions revealed that IOM was helpful in preventing a postoperative deficit in 5.2% of the monitored cases. CONCLUSIONS; For critical analysis of the benefits of IOM one must evaluate not only the findings of IOM and the patient's postoperative neurological condition but also the intraoperative findings and surgical interventions following a monitoring alarm. Evidence is presented that IOM is helpful in preventing a postoperative deficit.
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http://dx.doi.org/10.3171/jns.2002.96.2.0255DOI Listing
February 2002
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