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1.  Preoperative assessment of meningioma stiffness by magnetic resonance elastography 
Journal of neurosurgery  2012;118(3):643-648.
Object
To determine the potential of magnetic resonance elastography (MRE) to preoperatively assess the stiffness of meningiomas.
Methods
Thirteen subjects with meningiomas underwent a 3D brain MRE exam to measure stiffness in the tumor as well as the surrounding brain tissue. Blinded to the MRE results, the neurosurgeons made a qualitative assessment of tumor stiffness at the time of resection. The ability of MRE to predict the surgical assessment of stiffness was tested with a Spearman rank correlation.
Results
One case was excluded due to small tumor size. In the remaining 12 cases, both tumor stiffness alone (p=0.023) and the ratio of tumor stiffness to the stiffness in the surrounding brain tissue (p=0.0032) significantly correlated with the surgeons’ qualitative assessment of tumor stiffness. The results of the MRE exam provided a stronger correlation with the surgical assessment of stiffness compared to traditional T1 and T2 weighted imaging (p=0.089), particularly when considering meningiomas of intermediate stiffness.
Conclusions
In this cohort, MRE was able to predict the tumor consistency at the time of surgery. Tumor stiffness as measured by MRE outperformed conventional MRI since appearance on T1 and T2 images could only accurately predict the softest and hardest meningiomas.
doi:10.3171/2012.9.JNS12519
PMCID: PMC3920576  PMID: 23082888
meningioma; stiffness; consistency; MR elastography
2.  Meningeal Layers Around Anterior Clinoid Process as a Delicate Area in Extradural Anterior Clinoidectomy : Anatomical and Clinical Study 
Objective
Removal of the anterior clinoid process (ACP) is an essential process in the surgery of giant or complex aneurysms located near the proximal internal carotid artery or the distal basilar artery. An extradural clinoidectomy must be performed within the limits of the meningeal layers surrounding the ACP to prevent morbid complications. To identify the safest method of extradural exposure of the ACP, anatomical studies were done on cadaver heads.
Methods
Anatomical dissections for extradural exposure of the ACP were performed on both sides of seven cadavers. Before dividing the frontotemporal dural fold (FTDF), we measured its length from the superomedial apex attached to the periorbita to the posterolateral apex which connects to the anterosuperior end of the cavernous sinus.
Results
The average length of the FTDF on cadaver dissections was 7 mm on the right side and 7.14 mm on the left side. Cranial nerves were usually exposed when cutting FTDF more than 7 mm of the FTDF.
Conclusion
The most delicate area in an extradural anterior clinoidectomy is the junction of the FTDF and the anterior triangular apex of the cavernous sinus. The FTDF must be cut from the anterior side of the triangle at the periorbital side rather than from the dural side. The length of the FTDF incision must not exceed 7 mm to avoid cranial nerve injury.
doi:10.3340/jkns.2012.52.4.391
PMCID: PMC3488650  PMID: 23133730
Extradural clinoidectomy; Frontotemporal dural fold; Superior orbital fissure; Anatomical study
3.  Intracranial Dural Arteriovenous Fistulas: Clinical Characteristics and Management Based on Location and Hemodynamics 
Objective
A dural arteriovenous fistula (DAVF) generally refers to a vascular malformation of the wall of a major venous sinus. These lesions have diverse symptoms according to the location and venous drainage, and require multidisciplinary treatment. We report on our experience and analyze the treatment outcome of intracranial DAVFs for a nine-year period.
Methods
Between January 2000 and December 2008, 95 patients with intracranial DAVFs were enrolled in this study. A retrospective review of clinical records and imaging studies of all patients was conducted. Endovascular embolization, surgical interruption, gamma knife stereotactic radiosurgery (GKS), or combinations of these treatments were performed based on clinical symptoms, lesion location, and venous drainage pattern.
Results
Borden type I, II, and III were 34, 48, and 13 patients, respectively. Aggressive presentation was reported in 6% of Borden type I, 31% of Borden type II, and 77% of Borden type III DAVFs, respectively, and DAVFs involving transverse, sigmoid, and superior sagittal sinus. Overall, the rate of complete obliteration was 68%. The complete occlusion rates with a combination treatment of endovascular embolization and surgery, surgery alone, and endovascular embolization were 89%, 86%, and 80%, respectively. When GKS was used with embolization, the obliteration rate was 83%, although it was only 54% in GKS alone. Spontaneous obliteration of the DAVF occurred in three patients. There were a few complications, including hemiparesis (in microsurgery), intracranial hemorrhage (in endovascular embolization), and facial palsy (in GKS).
Conclusion
The hemorrhagic risk of DAVFs is dependent on the location and hemodynamics of the lesions. Strategies for treatment of intracranial DAVFs should be decided according to the characteristic of the DAVFs, based on the location and drainage pattern. GKS can be used as an optional treatment for intracranial DAVFs.
doi:10.7461/jcen.2012.14.3.192
PMCID: PMC3491214  PMID: 23210047
Dural arteriovenous fistula; Signs and symptoms; Therapeutics
4.  Cost-effectiveness analysis of endovascular versus neurosurgical treatment for ruptured intracranial aneurysms in the United States 
Journal of neurosurgery  2009;110(5):880-886.
Object
The results of the International Subarachnoid Aneurysm Trial (ISAT) demonstrated lower rates of death and disability with endovascular treatment (coiling) than with open surgery (clipping) to secure the ruptured intracranial aneurysm. However, cost-effectiveness may not be favorable because of the greater need for follow-up cerebral angiograms and additional follow-up treatment with endovascular methods. In this study, the authors’ goal was to compare the cost-effectiveness of endovascular and neurosurgical treatments in patients with ruptured intracranial aneurysms who were eligible to undergo either type of treatment.
Methods
Clinical data (age, sex, frequency of retreatment, and rebleeding) and quality of life values were obtained from the ISAT. Total cost included those associated with disability, hospitalization, retreatment, and rebleeding. Cost estimates were derived from the Premier Perspective Comparative Database, data from long-term care in stroke patients, and relevant literature. Incremental cost-effectiveness ratios (ICERs) were estimated during a 1-year period. Parametric bootstrapping was used to determine the uncertainty of the estimates.
Results
The median estimated costs of endovascular and neurosurgical treatments (in US dollars) were $45,493 (95th percentile range $44,693–$46,365) and $41,769 (95th percentile range $41,094–$42,518), respectively. The overall quality-adjusted life years (QALY) in the endovascular group was 0.69, and for the neurosurgical group it was 0.64. The cost per QALY in the endovascular group was $65,424 (95th percentile range $64,178–$66,772), and in the neurosurgical group it was $64,824 (95th percentile range $63,679–$66,086). The median estimated ICER at 1 year for endovascular treatment versus neurosurgical treatment was $72,872 (95th percentile range $50,344–$98,335) per QALY gained. Given that most postprocedure angiograms and additional treatments occurred in the 1st year and the 1-year disability status is unlikely to change in the future, ICER for endovascular treatment will progressively decrease over time.
Conclusions
Using outcome and economic data obtained in the US at 1 year after the procedure, endovascular treatment is more costly but is associated with better outcomes than the neurosurgical alternative among patients with ruptured intracranial aneurysms who are eligible to undergo either procedure. With accrual of additional years with a better outcome status, the ICER for endovascular coiling would be expected to progressively decrease and eventually reverse.
doi:10.3171/2008.8.JNS0858
PMCID: PMC2752732  PMID: 19199452
cost-effective analysis; endovascular coil placement; intracranial aneurysm; neurosurgical treatment; subarachnoid hemorrhage
5.  Treatment of Carotid Artery Stenosis: Medical Therapy, Surgery, or Stenting? 
Mayo Clinic Proceedings  2009;84(4):362-368.
With the aging of the general population and the availability of noninvasive imaging studies, carotid artery stenosis is a disease commonly seen in general medical practice. Differentiation between symptomatic and asymptomatic disease is critical to the treatment course because the natural history differs markedly between them. Antiplatelet therapy and aggressive treatment of vascular risk factors are the mainstays of medical therapy. Class I evidence shows that carotid endarterectomy (CEA) is effective in preventing ipsilateral ischemic events in patients with symptomatic moderate- and high-grade stenosis. The procedure is also effective in selected patients with asymptomatic stenosis, but the benefit is marginal. In the past decade, carotid angioplasty and stenting has been proposed as a valid alternative to CEA. Currently, it is unclear whether carotid angioplasty and stenting is as safe as CEA in patients with carotid artery stenosis who need invasive treatment. Large clinical trials are under way to answer this question.
PMCID: PMC2665982  PMID: 19339655
6.  The Middle Cranial Fossa: Morphometric Study and Surgical Considerations 
Skull Base  2007;17(6):395-403.
The anatomical features of the temporal bone can vary significantly among different individuals. These variations affect the operative view in middle cranial fossa surgery. We performed 18 middle fossa approaches in 9 cadaveric heads, with detailed morphological analysis, to identify unfavorable situations and reliable systems to avoid complications during surgery. We recorded linear, angular measurements and calculated areas. We performed a computed tomography (CT) scan with analysis of the amount of bone to remove in two temporal bones. We found that the location of the internal auditory canal (IAC) is the keystone of bone removal. We also found accuracy in the system suggested by E. and J. L. Garcia-Ibanez for its identification and that there is a smaller surgical window in female patients (statistically significant) that can be predicted on preoperative imaging studies. Our study also confirms significant individual variability in the mutual relationships of different surgical landmarks. We concluded that surgery of the middle fossa requires detailed understanding of the complex temporal bone anatomy. The surgeon has to be aware of extreme variability of the more commonly used anatomical landmarks. The method to identify the position of the IAC described by E. and J. L. Garcia-Ibanez seems to be the simplest and most reliable. When the surgical strategy includes an anterior petrosectomy, interindividual variability can critically affect the working area, particularly in females. The working area can be estimated on preoperative CT scans through the petrous bone.
doi:10.1055/s-2007-991117
PMCID: PMC2111136  PMID: 18449332
Middle fossa approach; temporal bone; landmarks; measurements; microsurgical anatomy; transpetrous approach
7.  A case of dural arteriovenous fistula with retrograde intracranial venous flow 
Presentation
Dural arteriovenous fistulae are relatively rare lesions which can present a variety of different symptoms ranging from tinnitus to devastating intracranial hemorrhage. For those fistulae that require treatment, therapy is available in a wide range of options. We describe the case of a 60-year old patient who presented with a right occipital lesion presumably secondary to a dural arteriovenous fistula of the right transverse-sigmoid junction. The patient underwent successful endovascular treatment of the fistula.
Discussion:
The participants in our discussion present their thoughts on how to evaluate and when and how to treat dural arteriovenous fistulae.
PMCID: PMC3317308  PMID: 22518208
Dural arteriovenous fistula; coil embolization; endovascular treatment; sinus thrombosis
8.  Paraseller Meningiomas 
Skull base surgery  1993;3(3):152-158.
Parasellar meningiomas frequently extend beyond the cavernous sinus into adjacent structures. In order to determine the incidence of involvement of adjacent sites, we retrospectively evaluated the computed tomography and nuclear magnetic resonance scans of 65 consecutive patients with meningiomas invading the cavernous sinus. Thirteen nearby anatomic sites were analyzed for tumor involvement. The sites most frequently involved were the lateral sphenoid sinus wall (93%), the ipsilateral petrous apex (70%), the ipsilateral posterior petrous bone surface (59%), the sella (59%), the intracranial clival surface (44%), and the suprasellar cistern (41%). The sella, clival bone marrow, orbital apex, pterygopalatine fossa, and prestyloid parapharyngeal space were more commonly involved in recurrent tumors. Lesions were also subdivided into five groups according to whether or not they involved only one part of the cavernous sinus (grade 1), two parts of the cavernous sinus (grade 2), surrounded the cavernous carotid artery (grade 3), surrounded and narrowed the cavernous carotid artery (grade 4), or involved both sides of the cavernous sinus (grade 5). Among the 63 cases that could be assigned to a category, seven were grade 1 lesions, 13 were grade 2, 13 were grade 3, 16 were grade 4, and 14 were grade 5. Tumor grade is helpful in predicting the difficulty of resection of the cavernous component of the tumor. The incidence of involvement of adjacent sites is also helpful in assessment of imaging studies and in planning the most appropriate surgical approach.
Images
PMCID: PMC1656439  PMID: 17170906

Results 1-8 (8)