Publications by authors named "Mustafa K Baskaya"

150 Publications

Brainatomy-Demystifying the Temporal Bone, Rule of 3-2-1.

Oper Neurosurg (Hagerstown) 2022 Feb;22(2):35-43

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

Background: The temporal bone is difficult to comprehend in three-dimensional (3D) space. We provide a novel 3D mental model of the temporal bone which helps clinicians and surgeons dealing with it in teaching, diagnosing, conservative managements, and preoperative and intraoperative orientation. This study is part of the scientific project Brainatomy.

Objective: To analyze and simplify the temporal bone anatomy to enhance its comprehension and long-term retention.

Methods: The study was conducted at the Neurosurgical Department of the University Hospital of Bochum, Germany. We retrospectively analyzed data sets of 221 adult patients who underwent computed tomography (CT) of the skull (n = 167) and magnetic resonance imaging (MRI) of the brain (n = 54). A total of 142 patients with their respective imaging scans remained in our pool of interest after excluding 79 scans. The raw digital imaging and communications in medicine scans were transformed into 3D objects. Spatial analyses were then conducted, and all collected data were used to create our own 3D model of the temporal bone.

Results: We define the temporal bone as a prism-shaped model and divide it into 6 compartments: apex, neurovascular, mastoid, blank, tympanic, and temporomandibular compartments. The division into compartments has been achieved with the "Rule of 3-2-1." Finally, the 3D model has been used to record a video (Video), using a novel and "easy-to-follow" didactic approach.

Conclusion: This simplified 3D model along with the corresponding video (Video) potentially enhances the efficiency of studying temporal none anatomy with a novel "easy-to-follow" approach.
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http://dx.doi.org/10.1227/ONS.0000000000000049DOI Listing
February 2022

Characterizing the relationship between lesion-activation distance using fMRI and verbal measures in brain tumor patients.

Interdiscip Neurosurg 2022 Mar 29;27. Epub 2021 Sep 29.

Department of Radiology, University of Wisconsin-Madison, Madison, WI, USA.

Functional resonance magnetic imaging (fMRI) allows for identification of eloquent cortex in pre-treatment planning. Previous studies have shown a correlation among lesion to activation distance (LAD) measures and morbidity and mortality. This study investigates the relationship between LAD, well-established language centers (Wernicke's and Broca's), and language performance measures. We included a sample population of brain tumor patients that received language fMRI (verbal fluency and sentence verification) for pre-treatment assessment (n = 51). LAD to the nearest language area was measured and divided into groups ≤ 10 mm and > 10 mm. Verbal fluency scores were compared between these groups. Additionally, patients were divided into similar groups based on LAD to either Broca's or Wernicke's areas, and the verbal fluency scores and sentence verification accuracy (n = 29) were subsequently compared between groups. Brain tumor patients with LAD ≤ 10 mm to either language area had significantly lower verbal fluency scores (p = 0.028). The difference in verbal fluency scores between groups with LAD ≤ 10 mm and > 10 mm to Wernicke's area trends toward significance (p = 0.067). The sentence verification accuracy was significantly lower in patients with LAD ≤ 10 mm to either language area (p = 0.039). These findings suggest that there exists a significant relationship between LAD to language centers and measures; greater language deficits are seen when LAD ≤ 10 mm.
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http://dx.doi.org/10.1016/j.inat.2021.101391DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8691738PMC
March 2022

The Suprasellar Meningioma Patient-Reported Outcome Survey: a disease-specific patient-reported outcome measure for resection of suprasellar meningioma.

J Neurosurg 2021 10 22(1). Epub 2021 Oct 22.

Department of Neurosurgery, Johns Hopkins University School of Medicine

Objective: Suprasellar meningioma resection via either the transcranial approach (TCA) or the endoscopic endonasal approach (EEA) is an area of controversy and active evaluation. Skull base surgeons increasingly consider patient-reported outcomes (PROs) when choosing an approach. No PRO measure currently exists to assess quality of life for suprasellar meningiomas.

Methods: Adult patients undergoing suprasellar meningioma resection between 2013 and 2019 via EEA (n = 14) or TCA (n = 14) underwent semistructured interviews. Transcripts were coded using a grounded theory approach to identify themes as the basis for a PRO measure that includes all uniquely reported symptoms. To assess content validity, 32 patients and 15 surgeons used a Likert scale to rate the relevance of items on the resulting questionnaire and the general Patient-Reported Outcomes Measurement Information System-29 (PROMIS29). The mean scores were calculated for all items and compared for TCA versus EEA patient cohorts by using unpaired t-tests. Items on either questionnaire with mean scores ≥ 2.0 from patients were considered meaningful and were aggregated to form the novel Suprasellar Meningioma Patient-Reported Outcome Survey (SMPRO) instrument.

Results: Qualitative analyses resulted in 55 candidate items. Relative to patients who underwent the EEA, those who underwent the TCA reported significantly worse future outlook before surgery (p = 0.01), tiredness from medications 2 weeks after surgery (p = 0.001), and word-finding and memory difficulties 3 months after surgery (p = 0.05 and < 0.001, respectively). The items that patients who received a TCA were most concerned about included medication-induced lethargy after surgery (2.9 ± 1.3), blurry vision before surgery (2.7 ± 1.5), and difficulty reading due to blurry vision before surgery (2.7 ± 2.7). Items that patients who received an EEA were most concerned about included blurry vision before surgery (3.5 ± 1.3), difficulty reading due to blurry vision before surgery (2.4 ± 1.3), and problems with smell postsurgery (2.9 ± 1.3). Although surgeons overall overestimated how concerned patients were about questionnaire items (p < 0.0005), the greatest discrepancies between patient and surgeon relevance scores were for blurry vision pre- and postoperatively (p < 0.001 and < 0.001, respectively) and problems with taste postoperatively (p < 0.001). Seventeen meningioma-specific items were considered meaningful, supplementing 8 significant PROMIS29 items to create the novel 25-item SMPRO.

Conclusions: The authors developed a disease- and approach-specific measure for suprasellar meningiomas to compare quality of life by operative approach. If demonstrated to be reliable and valid in future studies, this instrument may assist patients and providers in choosing a personalized surgical approach.

Abbreviations: EEA = endoscopic endonasal approach; GTR = gross-total resection; PRO = patient-reported outcome; PROMIS29 = Patient-Reported Outcomes Measurement Information System-29; QOL = quality of life; SMPRO = Suprasellar Meningioma Patient-Reported Outcome Survey; TCA = transcranial approach.
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http://dx.doi.org/10.3171/2021.6.JNS21517DOI Listing
October 2021

Ovoid Foramen Magnum Shape is Associated with Increased Complications and Decreased Extent of Resection for Anterolateral Foramen Magnum Meningiomas.

J Neurol Surg B Skull Base 2021 Dec 5;82(6):682-688. Epub 2020 Oct 5.

Department of Neurological Surgery, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin, United States.

 Antero-laterally located meningiomas of the foramen magnum (FM) pose significant surgical resection challenges. The effect of FM shape on surgical resection of FM meningiomas has not been previously studied. The present study investigates how FM shape effects the extent of tumor resection and complication rates in antero-lateral FM meningiomas.  This retrospective study included 16 consecutive patients with antero-lateral FM meningiomas operated on by a single surgeon. FMs were classified as ovoid (  = 8) and nonovoid (  = 8) using radiographic evaluation.  Sixteen patients were examined: seven males and nine females (mean age of 58.5, and range of 29 to 81 years). Gross total resection was achieved in 81% of patients, with tumor encased vertebral arteries in 44%. Patient characteristics were similar including age, sex, preoperative tumor volume, relationship of vertebral artery with tumor, preoperative Karnofsky performance score (KPS), symptom duration, and presence of lower cranial nerve symptoms. The ovoid FM group had lower volumetric extents of resection without statistical significance (93 ± 10 vs. 100 ± 0%,  = 0.069), more intraoperative blood loss (319 ± 75 vs. 219 ± 75 mL,  = 0.019), more complications per patient (1.9 ± 1.8 vs. 0.3 ± 0.4,  = 0.039), and poorer postoperative KPS (80 ± 21 vs. 96 ± 5,  = 0.007). Hypoglossal nerve palsy was more frequent in the ovoid FM group (38 vs. 13%).  This is the first study demonstrating that ovoid FMs may pose surgical challenges, poorer operative outcomes, and lower rates of extent of resection. Preoperative radiological investigation including morphometric FM measurement to determine if FMs are ovoid or nonovoid can improve surgical planning and complication avoidance.
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http://dx.doi.org/10.1055/s-0040-1715559DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8563267PMC
December 2021

Navigating a Carotico-Clinoid Foramen and an Interclinoidal Bridge in the Endonasal Endoscopic Approach: An Anatomical and Technical Note.

J Neurol Surg B Skull Base 2021 Oct 6;82(5):534-539. Epub 2020 Sep 6.

Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, United States.

 The carotico-clinoid foramen and interclinoid bridge are two anatomical variants of the sellar region. If these anatomical variants go unrecognized and are not managed safely by the surgeon during expanded endoscopic endonasal surgery for a posterior clinoidectomy, a carotid artery injury may occur. We summarize a method to safely navigate in the presence of the carotico-clinoid foramen and interclinoid bridge in an endoscopic endonasal approach.  The study involves cadaveric dissection and management of the anatomical variants.  The study took place in a cadaveric dissection laboratory.  The object of study is one cadaveric head.  After discovering the two variants in both cavernous sinuses of a cadaveric head, we established a stepwise coping strategy to avoid carotid artery injury while performing an endoscopic endonasal bilateral interdural pituitary transposition, and we report the final view after endoscopic management.  Debulking of the middle clinoid process can decrease the obstacle effect, and the pituitary transposition can be performed medial to the ossified carotico-clinoid ligament. Disconnection of the interclinoid bridge is the prerequisite to an effective posterior clinoidectomy, and distinguishing the transition between the sellar diaphragm and the interclinoid bridge is essential.  In the presence of both the carotico-clinoid foramen and the interclinoid bridge, a bilateral interdural pituitary transposition can still be performed, although preoperative strategic preparation, full inspection, and stepwise disconnections are of paramount importance in such a scenario to avoid cavernous carotid artery injury.
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http://dx.doi.org/10.1055/s-0040-1715470DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8421120PMC
October 2021

Neurotoxic Effects of Ammonia in a Patient With Ornithine Transcarbamylase Deficiency and Bilateral Brain Abscesses: Case Report.

Neurohospitalist 2021 Jul 9;11(3):241-245. Epub 2020 Nov 9.

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

Brain abscesses are a rare complication of dental procedures. High concentrations of ammonia in brain abscesses may increase vasogenic edema and other brain abscess symptoms. Ornithine transcarbamylase deficiency (OTCD) is an x-linked genetic disorder of the urea cycle associated with an increased risk of brain damage due to hyperammonia. During acute metabolic decompensations, due to stresses such as infection in OTCD patients, blood ammonia levels become moderately high. This, in turn, causes cerebral glutamine levels to increase and exacerbate cerebral edema and neurological symptoms. In this report, we present a 25-year-old woman with known partial OTCD who presented with bilateral brain abscesses 2 weeks after a wisdom tooth extraction. Neurotoxic effects of ammonia, from local ammonia formation in brain abscesses positive for streptococcus intermedius, or due to her OTCD, may have exacerbated the cerebral edema, which resulted in irreversible encephalopathy that lead to her death.
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http://dx.doi.org/10.1177/1941874420971154DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8182390PMC
July 2021

Hydrocephalus Following Giant Transosseous Vertex Meningioma Resection.

J Neurol Surg B Skull Base 2021 Jun 14;82(3):370-377. Epub 2019 Nov 14.

Department of Neurological Surgery, University of Wisconsin Hospitals and Clinics, Madison, Wisconsin, United States.

 Meningiomas are among the most common primary intracranial tumors. While well-described, there is limited information on the outcomes and consequences following treatment of giant-sized vertex-based meningiomas. These meningiomas have specific risks and potential complications due to their size, location, and involvement with extracalvarial soft tissue and dural sinuses. Herein, we present four giant-sized vertex transosseous meningioma cases with involvement and occlusion of the sagittal sinus, that postoperatively developed external hydrocephalus and ultimately required shunting.  A retrospective chart review identified patients with large vertex meningiomas that were: (1) large (>6 cm) with hemispheric (no skull base) location, (2) involvement of the superior sagittal sinus resulting in complete sinus occlusion, (3) involvement of dura resulting in a large duraplasty area, (4) transosseous involvement requiring a 5 cm or larger craniectomy for resection of invaded calvarial bone.  Tumors were resected in all four cases, with all patients subsequently developing external hydrocephalus which required shunting within 2 weeks to 6 months postsurgery.  We believe this may be the first report of the development of hydrocephalus following surgical resection of these large lesions. Based on our observations, we propose that a combination of superior sagittal sinus occlusion and changes in brain elasticity and compliance affect the brain's CSF absorptive capacity, which ultimately lead to hydrocephalus development. We suggest that neurosurgeons be aware that postoperative hydrocephalus can quickly develop following treatment of giant-sized vertex-based meningiomas, and that correction of hydrocephalus with shunting can readily be achieved.
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http://dx.doi.org/10.1055/s-0039-3400221DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8133808PMC
June 2021

Surgical approaches for resection of third ventricle colloid cysts: meta-analysis.

Neurosurg Rev 2021 Dec 15;44(6):3029-3038. Epub 2021 Feb 15.

Department of Neurological Surgery, University of Wisconsin-Madison, School of Medicine and Public Health, CSC K8/828, 600 Highland Avenue, Madison, WI, 53792, USA.

Although outcome studies and systematic reviews have been published on the surgical treatment of third ventricle colloid cysts (TVCC), there are no meta-analyses that compare the outcomes for various surgical approaches. This meta-analysis assesses the outcomes and complications for transcortical, transcallosal, and endoscopic surgical approaches used to excise TVCCs. A meta-analysis of surgically excised TVCCs was performed with an assessment of outcome for transcortical, transcallosal, and endoscopic approaches. A random-effects model analyzed the extent of surgical excision. The analysis included reports that compared at least two of these surgical approaches, for a total of 11 studies comprising a population of 301 patients. The transcortical approach was associated with a higher incidence of complete excision compared to the endoscopic approach (OR = 0.137, p = 0.041), with no significant differences observed between transcortical and transcallosal approaches, and between transcallosal and endoscopic approaches. Comparison between endoscopic and pooled microsurgical approaches was also insignificant (OR = 0.22, p = 1). The risk of motor weakness was increased with the transcortical approach compared to the endoscopic approach (OR = 6.10, p = 0.018). There were no significant differences between transcortical and transcallosal approaches regarding newly onset seizures, and no significant mortality differences between all three approaches. This study demonstrates that microsurgical approaches are associated with a greater extent of resection compared to endoscopic approaches; however, best results are likely achieved based on the surgeon's expertise, flexibility, and case review.
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http://dx.doi.org/10.1007/s10143-021-01486-5DOI Listing
December 2021

Demonstration of Microsurgical Technique and Nuances for the Resection of a Midbrain Tectal Glioma via the Transcollicular Approach: 3-Dimensional Operative Video.

Oper Neurosurg (Hagerstown) 2021 03;20(4):E304-E305

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

Tectal gliomas are a rare subset of intrinsic brainstem lesions. The microsurgical resection of these lesions remains a major challenge.1,2 Transcollicular approaches on one side, via the superior or inferior colliculi or both, are neurologically well tolerated without obvious or major auditory or oculomotor consequences. However, any postoperative acute visually triggered saccadic abnormalities caused by iatrogenic superior colliculus damage generally resolve during the postoperative period, as other oculomotor structures compensate for these functions in unilateral lesions.  In this surgical video, we present a 37-yr-old man with long-standing seizures, new onset headaches, progressive ataxic gait, and imbalance. Magnetic resonance imaging (MRI) showed a circumscribed nonenhancing dorsal midbrain cystic mass with compression on the aqueduct causing hydrocephalus. The lesion had a low signal intensity on T1-weighted images and a high signal intensity on T2-weighted images. The patient first underwent an endoscopic third ventriculostomy. Although his headaches greatly improved after the third ventriculostomy, he remained quite symptomatic in terms of gait imbalance and ataxia. The patient underwent a supracerebellar, infratentorial, transcollicular approach for resection of the tectal tumor. Simultaneously, motor and somatosensory evoked potentials were monitored.  Both the surgery and the postoperative course were uneventful, with postoperative MRI showing gross total resection of the mass, and histopathology indicating a WHO (World Health Organization) grade I pilocytic astrocytoma. The patient continued to do well without recurrence at 2-yr follow-up.  In this video, we demonstrate step-by-step microsurgical techniques for resecting these challenging tectal gliomas via the infratentorial-supracerebellar-transcollicular approach. The patient consented to the procedure and publication of his images.
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http://dx.doi.org/10.1093/ons/opaa411DOI Listing
March 2021

Demonstration of Microsurgical Technique and Nuances for the Obliteration of Complex Intracranial Dural Arteriovenous Fistulas in Three Consecutive Cases: Operative Video.

World Neurosurg 2021 01 14;145:434. Epub 2020 Oct 14.

Department of Neurological Surgery, University of Wisconsin Medical School and Public Health, Madison, Wisconsin, USA. Electronic address:

An intracranial dural arteriovenous fistula (DAVF) is an uncommon acquired dural shunt between an artery and a vein without a parenchymal nidus. DAVF occlusion may be achieved using either endovascular or open surgical means. Combining both techniques is also frequently used in clinical practice. In this video, we present 3 patients with Borden type III, complex intracranial DAVFs. The first patient presented with intracranial hemorrhage and underwent a successful microsurgical obliteration of the fistula in the tentorium. Two other patients had DAVFs that were incidentally found. Both underwent embolization procedures, which did not result in complete DAVF obliteration. Both patients then subsequently underwent microsurgical obliteration of these DAVFs. All 3 patients had very good outcomes. In 2 of these cases, we performed indocyanine green video angiography to identify fistulous connections. As demonstrated in this Video 1, microsurgical obliteration of DAVFs is relatively straightforward. This provides a valuable treatment option of some selected DAVFs and should be considered as a primary initial treatment option of complex DAVFs in certain locations. Open surgical obliteration is the best possible, most durable, and most effective therapeutic option when there are failures or shortcomings with endovascular management.
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http://dx.doi.org/10.1016/j.wneu.2020.10.038DOI Listing
January 2021

Trigeminal Neuralgia Caused by Vascular Compression from the Petrous Carotid Artery with Bony Erosion and Meckel Cave Encephalocele: Clinical Imaging with Surgical Video.

World Neurosurg 2021 01 9;145:360-362. Epub 2020 Oct 9.

Department of Neurological Surgery, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin, USA. Electronic address:

Trigeminal neuralgia (TN) is most commonly caused by neurovascular compression of the superior cerebellar artery. We present the first reported TN case where nerve compression was caused by the petrous internal carotid artery in the vicinity of a Meckel cave (MC) encephalocele. The patient underwent a pterional craniotomy for decompression of the gasserian ganglion and trigeminal nerve branches. All symptoms were resolved post surgery. We surmise that the principal cause of the TN was vascular compression from an exposed petrous internal carotid artery in the presence of an encephalocele. Causation was irrespective of whether the dehiscence in the petrous apex was a congenital defect or associated with destruction from the encephalocele. Based on this observation, we recommend that surgeons carefully consider all possible causes of patient symptoms as they prepare a meticulous dissection plan to avoid damage to surrounding neurovascular structures.
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http://dx.doi.org/10.1016/j.wneu.2020.09.165DOI Listing
January 2021

Intravenous Immunoglobulin (IVIG) in Severe Heparin-Induced Thrombocytopenia (HIT) in a Traumatic Brain Injury (TBI) Patient with Cerebral Venous Sinus Thrombosis (CVST).

Neurocrit Care 2021 06 30;34(3):1103-1107. Epub 2020 Sep 30.

Department of Neurological Surgery, University of Wisconsin Hospitals and Clinics, 600 Highland Avenue, Madison, WI, 53792, USA.

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http://dx.doi.org/10.1007/s12028-020-01101-3DOI Listing
June 2021

Extracranial-Intracranial Bypass as Primary Treatment for Internal Carotid Artery Blood Blister-Like Aneurysms, Not Just a Last Resort.

World Neurosurg 2021 01 28;145:320-322. Epub 2020 Sep 28.

Department of Neurological Surgery, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin, USA. Electronic address:

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http://dx.doi.org/10.1016/j.wneu.2020.09.130DOI Listing
January 2021

In Reply: Identification of the Distal Dural Ring and Definition of Paraclinoid Aneurysms According to Bony Landmarks on 3-Dimensional Computed Tomography Angiography: A Cadaveric and Radiological Study.

Oper Neurosurg (Hagerstown) 2020 10;19(5):E548-E549

Department of Neurological Surgery University of Wisconsin School of Medicine and Public Health Clinical Sciences Center K8/828 Madison, Wisconsin.

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http://dx.doi.org/10.1093/ons/opaa247DOI Listing
October 2020

Surgical Strategies for Cerebral Revascularization in Patients with Limited Bypass Conduit Options and Unexpected Intraoperative Difficulties.

World Neurosurg 2020 09 22;141:e959-e970. Epub 2020 Jun 22.

Department of Neurological Surgery, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin, USA. Electronic address:

Background: Cerebral bypass procedures are complex and require substantial experience and skills and thorough preoperative planning. Cerebrovascular surgeons face increasingly complex bypass cases because most routine cases are managed by endovascular means, and because increasing numbers of patients have complex medical problems that affect available and suitable bypass conduit options. We report the cases of several patients undergoing cerebral bypass with limited bypass conduit alternatives, in whom there were unexpected intraoperative difficulties requiring complex solutions.

Methods: The neurological surgery department database was reviewed to identify patients who had undergone cerebral bypass procedures during a 13-year period in whom there were limited available bypass conduits, and in whom unexpected intraoperative difficulties were encountered during cerebral bypass.

Results: Patient outcomes and graft patency were evaluated for 13 patients including 6 with ischemia, 3 with giant aneurysms, 2 with mycotic aneurysms, 1 with dissecting aneurysm, and 1 with gunshot-induced pseudoaneurysm. Median duration of follow-up was 43 months. In 12 of 13 patients, bypass graft/grafts were patent on the last computed tomography angiogram. In 1 patient, a prophylactic bypass procedure, the graft was not filling, probably because of lack of demand. Two patients died during follow-up of unrelated causes.

Conclusions: Cerebrovascular surgeons should be versatile in dealing with patients with complex bypass. When there are limited available conduit options, we find that collaboration with other surgical specialties (e.g., plastics and vascular) is helpful. In patients in whom extreme intraoperative difficulties are expected, thorough preoperative planning with multiple backup plans should be exercised, as described in this report.
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http://dx.doi.org/10.1016/j.wneu.2020.06.095DOI Listing
September 2020

Intraoperative Shortening of Aneurysm Clips: Revisiting an Old Technique in a New Era.

World Neurosurg 2020 07 24;139:361-369. Epub 2020 Apr 24.

Department of Neurological Surgery University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA. Electronic address:

Background: It can sometimes be challenging to find a suitable clip to treat an unusual aneurysm, or when the surrounding anatomy is unusual, especially in resource-limited environments. We describe a method to modify aneurysm clips based on the method originated by Sugita et al in 1985. Herein clip modification (Clip-Mod) is used to treat anatomically difficult anterior communicating artery aneurysms.

Methods: The Department of Neurological Surgery database was reviewed to find aneurysm patients treated using modified aneurysm clips. Clip-Mod was performed during surgery by shortening the tines of titanium aneurysm clips by abrasion applied from the side of a standard 3-mm surgical diamond drill bit under constant irrigation. Note that the thickness of the tines and the clip spring were not modified or contacted by the drill.

Results: Four cases used modified aneurysm clips, from 648 total clip-treated aneurysms (0.6%) by 2 surgeons over a 14-year period. Three patients presented with subarachnoid hemorrhages that were determined to be due to anterior communicating artery aneurysms. One patient presented with an incidental unruptured anterior communicating artery aneurysm. All 4 patients were treated with 3-mm titanium clips shortened intraoperatively to 1- to 2-mm lengths, to achieve aneurysm obliteration without stenosing parent or perforating vessels.

Conclusions: All 4 patients have done well clinically with no reoccurrences after 2-6 years' follow-up, which included angiographic evaluation. The use of this "Clip-Mod" technique thus appears useful for anterior communicating artery aneurysms. Clip-Mod could also be considered for treating other aneurysms when the "perfect" length clip is not available.
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http://dx.doi.org/10.1016/j.wneu.2020.04.099DOI Listing
July 2020

Surgical management of craniopharyngiomas in adult patients: a systematic review and consensus statement on behalf of the EANS skull base section.

Acta Neurochir (Wien) 2020 05 28;162(5):1159-1177. Epub 2020 Feb 28.

Department of Neurosurgery, University Hospital of Lausanne, Lausanne, Switzerland.

Background And Objective: Craniopharyngiomas are locally aggressive neuroepithelial tumors infiltrating nearby critical neurovascular structures. The majority of published surgical series deal with childhood-onset craniopharyngiomas, while the optimal surgical management for adult-onset tumors remains unclear. The aim of this paper is to summarize the main principles defining the surgical strategy for the management of craniopharyngiomas in adult patients through an extensive systematic literature review in order to formulate a series of recommendations.

Material And Methods: The MEDLINE database was systematically reviewed (January 1970-February 2019) to identify pertinent articles dealing with the surgical management of adult-onset craniopharyngiomas. A summary of literature evidence was proposed after discussion within the EANS skull base section.

Results: The EANS task force formulated 13 recommendations and 4 suggestions. Treatment of these patients should be performed in tertiary referral centers. The endonasal approach is presently recommended for midline craniopharyngiomas because of the improved GTR and superior endocrinological and visual outcomes. The rate of CSF leak has strongly diminished with the use of the multilayer reconstruction technique. Transcranial approaches are recommended for tumors presenting lateral extensions or purely intraventricular. Independent of the technique, a maximal but hypothalamic-sparing resection should be performed to limit the occurrence of postoperative hypothalamic syndromes and metabolic complications. Similar principles should also be applied for tumor recurrences. Radiotherapy or intracystic agents are alternative treatments when no further surgery is possible. A multidisciplinary long-term follow-up is necessary.
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http://dx.doi.org/10.1007/s00701-020-04265-1DOI Listing
May 2020

Grapefruit Training Model for Distal Anterior Cerebral Artery Side-to-Side Bypass.

World Neurosurg 2020 06 25;138:39-51. Epub 2020 Feb 25.

Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.

Objective: Simulation models enable trainees to master microsurgical skills before performing surgeries. Vascular bypass is a critical component of cerebrovascular and many nonneurologic procedures. However, most available bypass training models lack important spatial, tactile, and physiologic aspects of real surgery. Animal and placental models provide true physiology but are expensive. While some models adequately simulate superficial temporal artery-middle cerebral artery bypass, there is no model for side-to-side distal anterior cerebral artery bypass. The objective is to create a realistic and inexpensive training model for this important procedure.

Methods: The depth of interhemispheric fissures in cadaver brains was compared with the grapefruit radii. Grapefruits were dissected to simulate the operative field within the deep and narrow interhemispheric fissure. Pericallosal arteries were mimicked with chicken wing vessels or synthetic tubing, with an aquarium pump providing closed circulation. Twelve board-certified neurosurgeons who were given bypass training using the grapefruit model were blindly surveyed on model realism and training suitability.

Results: Grapefruit depths from pith to central column were comparable with interhemispheric cadaveric fissure depths. Approximate preparation time of grapefruit training models was 5-10 minutes. Surveyed neurosurgeons rated the model a better replicate for cerebral artery bypass (P < 0.02) and more challenging than common training models (P < 0.01). They also rated the grapefruit model as likely to be superior for improving surgical skills before surgery (P < 0.05).

Conclusions: This grapefruit model provides a realistic simulation of side-to-side distal anterior cerebral artery bypass procedure that can be inexpensively and easily implemented in nearly any resource environment.
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http://dx.doi.org/10.1016/j.wneu.2020.02.107DOI Listing
June 2020

Identification of the Distal Dural Ring and Definition of Paraclinoid Aneurysms According to Bony Landmarks on 3-Dimensional Computed Tomography Angiography: A Cadaveric and Radiological Study.

Oper Neurosurg (Hagerstown) 2020 09;19(3):319-329

University of Wisconsin Hospital, Madison, Wisconsin.

Background: Determining if paraclinoid aneurysms are intradural or extradural is critical for surgical planning.

Objective: To create an easily reproducible diagnostic method based on bony anatomy that precisely locates the distal dural ring (DDR) to determine the position of paraclinoid aneurysms as intradural, transitional, or extradural.

Methods: Bilateral anatomic dissections of 10 cadaveric heads (20 sides) were performed to evaluate DDR anatomy. We observed a plane that reflects the position of the DDR passes through 4 bony landmarks: 1) The anterior clinoid-internal carotid artery intersection, 2) the optic strut, 3) the optico-carotid elevation, and 4) the base of the posterior clinoid process. This landmark-based plane can thus define the location of the DDR using 3-dimensional computed tomography angiography (CTA). This was confirmed in 27 surgical patients with intradural/transitional aneurysms and 7 patients with extradural aneurysms confirmed with magnetic resonance imaging (MRI). The DDR plane method easily classified aneurysm locations as intradural (above the DDR plane), extradural (below the DDR plane), or transitional (the DDR plane crosses the aneurysm). The aneurysm's location was subsequently confirmed intraoperatively or with MRI.

Results: The DDR plane method determined if paraclinoid aneurysms were intradural, transitional, or extradural in all 34 cases examined. The visibility of the anatomic features that define the DDR plane was also verified in 82% to 89% of CTA images from 100 patients.

Conclusion: The DDR plane method provides a useful diagnostic tool to evaluate the position of the DDR and determine the anatomic location of paraclinoid aneurysms.
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http://dx.doi.org/10.1093/ons/opz417DOI Listing
September 2020

From Ibni Sina (Avicenna) to Present, History of International Fellowship and Observership: University of Wisconsin-Madison Experience.

Turk Neurosurg 2020 ;30(2):159-162

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

Since the inception of the International Fellowship (IF) Program in the Department of Neurological Surgery at the University of Wisconsin-Madison in 2006, training has been provided to 219 residents, neurosurgeons, and medical students from 18 countries and five continents. These IFs took a long academic and geographic journey to improve their skills in patient care. The advanced training, they received lead to 14 of these IF neurosurgeons to return to their hometowns with higher academic appointments, including two chairmen, seven professors, two associate professors, two assistant professors, and one consultant neurosurgeon. An additional measure of success for the IF Program is that fellows continue to communicate with their mentors and with their prior fellow international colleagues long after their fellowship ends.
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http://dx.doi.org/10.5137/1019-5149.JTN.28738-19.0DOI Listing
August 2020

Spontaneous Subarachnoid Hemorrhage From a Pure Pial Arterial Malformation in the Lateral Cerebellomedullary Junction: Clinical Images with a Surgical Video.

World Neurosurg 2020 Mar 24;135:214-216. Epub 2019 Dec 24.

Department of Neurological Surgery, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin, USA. Electronic address:

Pure pial arterial malformations (PAMs) are poorly understood owing to the limited number of reported cases. Because PAMs have been thought to have a benign natural history, they have generally been managed conservatively, unlike arteriovenous malformations or arteriovenous fistulas. In the present report, we have described a spontaneous subarachnoid hemorrhage from the rupture of a PAM at the cerebellomedullary junction. This hemorrhage was surgically treated using clip trapping.
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http://dx.doi.org/10.1016/j.wneu.2019.12.093DOI Listing
March 2020

A Plea to Reconsider the Diagnosis.

J Hosp Med 2020 02 23;15(2):111-115. Epub 2019 Dec 23.

Department of Pediatrics, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin.

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http://dx.doi.org/10.12788/jhm.3348DOI Listing
February 2020

Aggressive, Multidisciplinary Staged Microsurgical Resection of a Giant Cervicomedullary Junction Chordoma.

J Neurol Surg B Skull Base 2019 Dec 4;80(Suppl 4):S378-S379. Epub 2019 Oct 4.

Department of Neurological Surgery, University of Wisconsin Medical School, Madison, Wisconsin, United States.

Chordomas of the cranial base are locally destructive tumors since they are surrounded by significant complex neurovascular structures. Thus, their surgical removal is challenging, recurrence rates are high, and their therapeutic strategies remain controversial. In this video, we present a 47-year-old man with a recent onset of swallowing difficulties, hoarseness, and weight loss for several weeks. In the neurological examination, he had complete paralysis of the 9th, 10th, 11th, and 12th cranial nerves. Magnetic resonance imaging (MRI) showed a heterogeneously enhancing expansile invasive mass lesion centered within the clivus and involving the C1, the occipitocervical junction, the retropharynx, and the hypoglossal canal. The decision was made to proceed with multiple staged surgeries. In the first surgical stage, we performed a mastoidectomy with the infralabyrinthine approach to perform a test clip ligation of the sigmoid sinus and to resect the tumor component that extended into the infralabyrinthine space. In the second stage, we performed a far-lateral transcondylar approach for tumor resection and occipitocervical fusion. In the third stage, we used a transoral approach with endoscopic assistance to complete the excision of the remaining tumor in the retropharyngeal space and anterior aspect of C1 and C2 bodies that were not accessible in the first two stages. The surgeries and postoperative course were uneventful. Postoperative MRI showed a gross total resection of the tumor. Histopathology indicated a chordoma. The patient subsequently received proton radiotherapy and has continued to do well without recurrence at 14 months' follow-up. The link to the video can be found at: https://youtu.be/uP9OSlKg_rE .
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http://dx.doi.org/10.1055/s-0039-1695062DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6900546PMC
December 2019

Microsurgical Gross Total Resection of Foramen Magnum Meningioma via Far Lateral Approach.

J Neurol Surg B Skull Base 2019 Dec 15;80(Suppl 4):S360-S362. Epub 2019 Oct 15.

Department of Neurological Surgery, University of Wisconsin Medical School, Madison, Wisconsin, United States.

Foramen magnum meningiomas are one of the most challenging tumors for skull base neurosurgeons due to their proximity to critical neurovascular structures. The far-lateral approach demonstrated here facilitates access to lesions involving the anterior portion of the foramen magnum. In this video, we present a 62-year-old woman with hand numbness and weakness. The patient had significant difficulty in fine motor movements of both hands. In the neurological examination, she had a significant right-hand intrinsic muscle weakness and mild quadriparesis. Magnetic resonance imaging (MRI) showed a dural-based homogeneously enhancing extra-axial mass in the anterior foramen magnum with a significant mass effect on the brain stem and the upper cervical cord. The decision was made to proceed with a far lateral transcondylar skull base approach including partial C1 laminectomy. The surgery and postoperative course were uneventful. The postoperative MRI showed gross total resection of the mass. The histopathology indicated a WHO (World health Organization) grade-I meningioma. The patient's postoperative course was uneventful. She improved to normal neurological function within several weeks and continues to do well without recurrence at 20 months' follow-up. In this video, we demonstrated important steps for the microsurgical resection of these challenging lesions. The link to the video can be found at: https://youtu.be/_nuX2Y7YU9w .
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http://dx.doi.org/10.1055/s-0039-1695063DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6864356PMC
December 2019

Delayed Onset Abducens Nerve Palsy following Uncomplicated Large Cystic Vestibular Schwannoma Resection: Case Report.

J Neurol Surg Rep 2019 Oct 30;80(4):e37-e40. Epub 2019 Oct 30.

Department of Neurological Surgery, University of Wisconsin Medical School, Madison, Wisconsin, United States.

Although delayed facial palsy after vestibular schwannoma (VS) surgery is a poorly understood but a well-known phenomenon, other delayed cranial nerve palsies in the cerebellopontine angle have not been reported after VS surgery. In this report, we describe a 54-year-old woman with a large cystic VS who experienced double vision and a new delayed onset right abducens nerve (AbN) palsy, 3 weeks after gross total resection of VS via a translabyrinthine approach. To the best of our knowledge, this is the first report describing delayed isolated AbN palsy after uncomplicated VS surgery. Magnetic resonance imaging findings and the management of this complication following VS surgery are discussed in this case report.
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http://dx.doi.org/10.1055/s-0039-1694737DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6821525PMC
October 2019

Gross Total Resection of a Grade IV Astrocytoma Adjacent to the Precentral Gyrus With Nonawake Motor Mapping and Motor-Evoked Potential Monitoring: 3-Dimensional Operative Video.

Oper Neurosurg (Hagerstown) 2020 Apr;18(4):E127-E128

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

Surgical treatment of the gliomas located in or adjacent to the eloquent areas poses significant challenge to neurosurgeons. The main goal of the surgery is to achieve maximal safe resection while preserving the neurological function. This might be possible with utilizing pre- and intraoperative adjuncts such as functional magnetic resonance imaging (MRI), image guidance, mapping of the function of interest, intraoperative MRI, and neurophysiological monitoring. In this video, we demonstrate the utilization of nonawake mapping and motor-evoked potential (MEP) monitoring for the resection of a right-sided posterior superior frontal gyrus grade IV astrocytoma adjacent to the primary motor cortex. The patient is a 69-yr-old woman presented with multiple episodes of simple partial seizures involving her left leg and spreading to the left arm. MRI and functional MRI examinations showed a heterogeneously enhancing mass with peritumoral edema adjacent to the primary motor cortex. Because the patient did not want to undergo an awake craniotomy, a decision was made to perform the resection of the tumor with nonawake motor mapping and continuous MEP monitoring. Nonawake motor mapping and MEP monitoring enabled us to perform gross total resection. Because it has been shown that supratotal resection may provide improved survival outcome,1,2 we extended the white matter resection beyond the contrast enhancing area in noneloquent parts of the tumor. Surgical steps in dealing with vascular anatomy as well as utilizing intraoperative adjuncts such as motor mapping and MEP monitoring to enhance the extent of resection while preserving the function are demonstrated in this 3-dimensional surgical video.  The patient consented to publication of her operative video.
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http://dx.doi.org/10.1093/ons/opz185DOI Listing
April 2020

Effect of perioperative aspirin use on hemorrhagic complications in elective craniotomy for brain tumors: results of a single-center, retrospective cohort study.

J Neurosurg 2019 Apr 5;132(5):1529-1538. Epub 2019 Apr 5.

Objective: In daily practice, neurosurgeons face increasing numbers of patients using aspirin (acetylsalicylic acid, ASA). While many of these patients discontinue ASA 7-10 days prior to elective intracranial surgery, there are limited data to support whether or not perioperative ASA use heightens the risk of hemorrhagic complications. In this study the authors retrospectively evaluated the safety of perioperative ASA use in patients undergoing craniotomy for brain tumors in the largest elective cranial surgery cohort reported to date.

Methods: The authors retrospectively analyzed the medical records of 1291 patients who underwent elective intracranial tumor surgery by a single surgeon from 2007 to 2017. The patients were divided into three groups based on their perioperative ASA status: 1) group 1, no ASA; 2) group 2, stopped ASA (low cardiovascular risk); and 3) group 3, continued ASA (high cardiovascular risk). Data collected included demographic information, perioperative ASA status, tumor characteristics, extent of resection (EOR), operative blood loss, any hemorrhagic and thromboembolic complications, and any other complications.

Results: A total of 1291 patients underwent 1346 operations. The no-ASA group included 1068 patients (1112 operations), the stopped-ASA group had 104 patients (108 operations), and the continued-ASA group had 119 patients (126 operations). The no-ASA patients were significantly younger (mean age 53.3 years) than those in the stopped- and continued-ASA groups (mean 64.8 and 64.0 years, respectively; p < 0.001). Sex distribution was similar across all groups (p = 0.272). Tumor locations and pathologies were also similar across the groups, except for deep tumors and schwannomas that were relatively less frequent in the continued-ASA group. There were no differences in the EOR between groups. Operative blood loss was not significantly different between the stopped- (186 ml) and continued- (220 ml) ASA groups (p = 0.183). Most importantly, neither hemorrhagic (0.6%, 0.9%, and 0.8%, respectively; p = 0.921) nor thromboembolic (1.3%, 1.9%, and 0.8%; p = 0.779) complication rates were significantly different between the groups, respectively. In addition, the multivariate model revealed no statistically significant predictor of hemorrhagic complications, whereas male sex (odds ratio [OR] 5.9, 95% confidence interval [CI] 1.7-20.5, p = 0.005) and deep-extraaxial-benign ("skull base") tumors (OR 3.6, 95% CI 1.3-9.7, p = 0.011) were found to be independent predictors of thromboembolic complications.

Conclusions: In this cohort, perioperative ASA use was not associated with the increased rate of hemorrhagic complications following intracranial tumor surgery. In patients at high cardiovascular risk, ASA can safely be continued during elective brain tumor surgery to prevent potential life-threatening thromboembolic complications. Randomized clinical trials with larger sample sizes are warranted to achieve a greater statistical power.
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http://dx.doi.org/10.3171/2018.12.JNS182483DOI Listing
April 2019

Low-Cost Stereoscopic Recordings of Neurologic Surgery Operative Microscopy for Anatomic Laboratory Training.

World Neurosurg 2019 05 15;125:240-244. Epub 2019 Feb 15.

Department of Neurological Surgery, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin, USA. Electronic address:

Objective: Stereoscopic video recordings of operative microscopy during neuroanatomic dissections are an important component of surgical training and research in well-financed medical schools and teaching hospitals. However, the high cost of the latest operative microscopes with integrated video recording equipment can be a limiting factor in their worldwide use. The aim of the present work is to provide a simple low-cost 3-dimensional (3D) stereoscopic operative microscope recording system that can be used even in economically and resource-limited locations. This is achieved by using readily available smartphones, smartphone accessories, and computer software.

Methods: Stereoscopic recording is accomplished by attaching and aligning matched or similar smartphones to the eyepieces of an operative microscope using readily available smartphone mounting connectors. Video recordings from the smartphones are then transferred to a personal computer and processed with a video-editing software to generate stereoscopic movies that are viewed on a smartphone using virtual-reality glasses.

Results: The setup time to mount and align the smartphone cameras typically requires 15-30 minutes. Video image quality and 3D depth presentation is more than sufficient for surgical training and research purposes. The implementation cost ranges from $1,315-$7,066, or much less if smartphones and a computer are already available.

Conclusions: The 3D video system demonstrated herein can be implemented on any type of operative microscope, including older units for which commercial stereo recording systems are not available. The system and method presented herein can be readily and affordably implemented in low-budget environments for clinical training and research.
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http://dx.doi.org/10.1016/j.wneu.2019.01.237DOI Listing
May 2019

Revascularization for Cerebral Ischemia, Step-by-Step Demonstration of Bonnet Bypass: 3-Dimensional Operative Video.

Oper Neurosurg (Hagerstown) 2019 Sep;17(3):E113

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

The superficial temporal artery (STA) to the middle cerebral artery (MCA) bypass is the most common bypass type for revascularization to treat cerebral ischemia. If the ipsilateral STA is not available for anastomosis, various options for bypass conduits can be exercised. When the entire ipsilateral external carotid and its branches are not available, the contralateral STA may be used as a donor artery through an interposition graft. This technique is known as a "bonnet bypass." In this video, we demonstrate the utilization of a bonnet bypass in a 48-yr-old man with protein S deficiency, and right carotid artery occlusion with recurrent strokes and transient ischemic attacks (TIA). After exhausting nonsurgical options by treating with 2 antiplatelet drugs and supportive lifestyle changes, the patient continued to experience TIAs and watershed strokes in the right hemisphere. Angiography showed that the right anterior artery and the MCA were filled through the Circle of Willis, but the ipsilateral STA and entire external and common carotid arteries were not patent for potential use as a bypass donor. Since the ipsilateral bypass options were not available, we elected to perform a bypass from the contralateral STA trunk to the ipsilateral M2 with a saphenous vein interposition graft, for a so-called bonnet bypass. The patient did well after surgery and has remained symptom-free for 19 mo post bypass. The surgical technique and each step in performing this bonnet bypass are demonstrated in this 3-dimensional video. The patient consented to the publication of his operative video.
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http://dx.doi.org/10.1093/ons/opy400DOI Listing
September 2019

Microsurgical Gross Total Resection of a WHO Grade II Cerebellopontine Angle Ependymoma in an Adult.

J Neurol Surg B Skull Base 2018 Dec 25;79(Suppl 5):S426-S427. Epub 2018 Sep 25.

Department of Neurological Surgery, University of Wisconsin Medical School, Madison, Wisconsin, United States.

Infratentorial ependymomas that arise in the fourth ventricle and extend into the cerebellopontine angle (CPA) through the foramina of Luschka are well described. However, a primary CPA location of an ependymoma is distinctly uncommon. In this video, we present a 46-year-old man with episodes of dizziness, left-sided tinnitus, imbalance, double vision, and nausea. An magnetic resonance imaging (MRI) scan of the head showed a large mass lesion centered in the CPA with heterogenous enhancement. Differential diagnosis included ependymoma, meningioma, schwannoma of the vestibular nerve, or lower cranial nerves, and choroid plexus papilloma. He underwent microsurgical gross total resection of the tumor via a retrosigmoid approach. Direct stimulation of the cranial nerves was performed throughout the case and there was no attachment of the tumor to any cranial nerve to suggest that this might be a schwannoma. The tumor encased important vasculature, including the posterior-inferior cerebellar artery. The histopathology was a grade II ependymoma. The patient tolerated the surgery well and his postoperative course was uneventful. He remained neurologically intact. He received radiation therapy and there was no recurrent or residual disease on follow-up studies. This video demonstrates important steps of the surgical approach and microsurgical resection techniques for this type of challenging tumor. The link to the video can be found at: https://youtu.be/KK-y6EYh888 .
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http://dx.doi.org/10.1055/s-0038-1669969DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6243230PMC
December 2018
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