bluuebunny/crossref_metadata_2025_split huggingface dataset:
The neurovascular triad: mixed cavernous, capillary, and venous malformations of the brainstem
Authors: Pozzati Eugenio , Marliani Anna Federica , Zucchelli Mino , Foschini Maria Pia , Dall'Olio Massimo , Lanzino Giuseppe 
Published: December 2007

Object
The four types of cerebrovascular malformations may sometimes be combined and more often occur in pairs; triads are exceptional. The authors present six patients with the clinicoradiographic profile of mixed vascular malformations of the brainstem, including cavernous malformation (CM), capillary telangiectasia, and developmental venous anomaly (DVA).

Methods
Five patients (one of whom was a child) suffered from hemorrhage, suggesting that this complex association has a high bleeding potential. Progressive growth, rebleeding, and de novo occurrence of the associated CM were documented in three cases. Magnetic resonance imaging of the brain was obtained in all patients by using one or more of the following modalities: T1-weighted sequences before and after gadolinium administration; T2-weighted sequences; T2-weighted fluid attenuated inversion recovery; T1-weighted fast spin echo; and diffusion weighted, diffusion tensor, and perfusion imaging in three cases.

Results
Three patients were surgically treated with the intention of excising the hemorrhagic lesion, but only two patients had their malformations successfully removed. In the third case, diffuse pontine telangiectasia precluded the safe excision of the CM. Histological examination demonstrated a blended pathological milieu characterized by coalescent telangiectasia and venules associated with loculated endothelial chambers resembling an immature or de novo CM. Three patients were treated conservatively; recurrent minor hemorrhage occurred in one case. The authors found these malformations to be arranged in two basic relationships: CM inside the telangiectasia and CM in the radicles of the DVA. Stenosis of the main venous collector and dilation of the medullary veins were important findings.

Conclusions
The pathogenesis of this malformation may be referred to a developmental deviance of the brainstem capillary–venous network associated with transitional vessels and loculated endothelial vascular spaces related to genetic and acquired origins, probably in a restrictive venous outflow milieu.
Treatment of dural arteriovenous fistula using ethylene vinyl alcohol (Onyx) arterial embolization as the primary modality: short-term results
Authors: Carlson Andrew P. , Taylor Christopher L. , Yonas Howard 
Published: December 2007

Object
A dural arteriovenous fistula (DAVF) typically involves meningeal feeding arteries and can cause clinical symptoms ranging from tinnitus to rupture of draining cortical or parenchymal veins. Surgical treatment may be technically demanding. Ethylene vinyl alcohol (Onyx, ev3 Neurovascular) has several properties that make it potentially useful as a primary treatment agent for DAVF. Onyx is expected to be a permanent embolic agent. It should have a decreased risk of catheter retention when compared with other permanent embolic materials.

Methods
The authors report a series of six patients with symptomatic DAVF who were treated initially with transarterial Onyx embolization and other endovascular techniques.

Results
Five patients had complete occlusion of their DAVF noted on the follow-up angiogram obtained between 2 and 4 months. One patient had residual filling via a small arterial branch that was stable on follow-up angiography. None of the patients had worsening of neurological function. One case was complicated by a retained catheter fragment.

Conclusions
Transarterial Onyx embolization and other endovascular methods can angiographically obliterate DAVF. In some cases, embolization allowed occlusion of multiple arterial feeding arteries from a single arterial injection. Technically, the embolization was optimized when a microcatheter position immediately adjacent to the point(s) of fistulization was achieved.
Evaluation of olfactory nerve function after aneurysmal subarachnoid hemorrhage and clip occlusion
Authors: de Vries Joost , Menovsky Tomas , Ingels Koen 
Published: December 2007

Object
In this study, the olfactory nerve function (ONF) in patients with an aneurysmal subarachnoid hemorrhage (SAH) who underwent neurosurgical clip occlusion for intracranial aneurysm was assessed pre- and postoperatively.

Methods
In 13 patients with an aneurysmal SAH who underwent a frontobasal or frontotemporal neurosurgical procedure for clipping of a ruptured intracranial aneurysm, ONF was assessed pre- and postoperatively by using a standardized olfactory test battery (“Sniffin' Sticks”). Preoperative testing was performed within the first 72 hours after SAH. For their follow-up visit, patients were tested 3 months after surgery. Olfactory thresholds, odor discrimination, and odor identification were documented. Only cooperative patients were included, and as a result, all patients enrolled in the study were classified in Hunt and Hess Grade II.

Results
After SAH and before surgery, three patients were normosmic, seven were hyposmic, and three were anosmic according to the Sniffin' Sticks test. Thus, 10 of 13 patients with SAH already showed disturbance of ONF preoperatively. Of these 10, however, only two patients experienced reduced smell and taste sensation. At the 3-month follow-up review, 10 patients could be tested. Three normosmic patients remained normosmic. In one patient, ONF had improved from anosmic to hyposmic, whereas in another patient, ONF had worsened from hyposmic to anosmic. Thus, in eight patients, ONF remained unchanged after surgery. Three patients reported disturbed smell and/or taste sensation. One anosmic patient had experienced no smell sensation since surgery; however, he reported his taste to be normal. Another hyposmic patient experienced both reduced smell and taste sensation. One normosmic patient reported normal smelling ability but disturbed taste sensation.

Conclusions
This study provides evidence that aneurysmal SAH causes disturbance of ONF in a substantial number of cases. With the exception of one case, neurosurgical treatment did not alter a preexisting olfactory deficit. Improvement of SAH-induced olfactory dysfunction at follow-up, however, can also be documented. The subjective assessments of the patients do not correspond well with the test battery results.
Intracranial hemorrhage associated with cerebral hyperperfusion syndrome following carotid endarterectomy and carotid artery stenting: retrospective review of 4494 patients
Authors: Ogasawara Kuniaki , Sakai Nobuyuki , Kuroiwa Terumasa , Hosoda Kohkichi , Iihara Koji , Toyoda Kazunori , Sakai Chiaki , Nagata Izumi , Ogawa Akira , _ _ 
Published: December 2007

Object
Intracranial hemorrhage associated with cerebral hyperperfusion syndrome (CHS) following carotid endarterectomy (CEA) or carotid artery stenting (CAS) is a rare but potentially devastating complication. In the present study the authors evaluated 4494 patients with carotid artery stenosis who had undergone CEA or CAS to clarify the clinicopathological features and outcomes of those with CHS and associated intracranial hemorrhage.

Methods
Patients with postoperative CHS were retrospectively selected, and clinicopathological features and outcomes were studied.

Results
Sixty-one patients with CHS (1.4%) were identified, and intracranial hemorrhage developed in 27 of them (0.6%). The onset of CHS peaked on the 6th postoperative day in those who had undergone CEA and within 12 hours in those who had undergone CAS. Results of logistic regression analysis demonstrated that poor postoperative control of blood pressure was significantly associated with the development of intracranial hemorrhage in patients with CHS after CEA (p = 0.0164). Note, however, that none of the tested variables were significantly associated with the development of intracranial hemorrhage in patients with CHS after CAS. Mortality (p = 0.0010) and morbidity (p = 0.0172) rates were significantly higher in patients with intracranial hemorrhage than in those without.

Conclusions
Cerebral hyperperfusion syndrome after CEA and CAS occurs with delayed classic and acute presentations, respectively. Although strict control of postoperative blood pressure prevents intracranial hemorrhage in patients with CHS after CEA, there appears to be no relationship between blood pressure control and intracranial hemorrhage in those with CHS after CAS. Finally, the prognosis of CHS in patients with associated intracerebral hemorrhage is poor.
Intraoperative three-dimensional visualization in microvascular decompression
Authors: Tanrikulu Levent , Hastreiter Peter , Troescher-Weber Regina , Buchfelder Michael , Naraghi Ramin 
Published: December 2007

Object
The authors systematically analyzed 3D visualization of neurovascular compression (NVC) syndromes in the operating room (OR) during microvascular decompression (MVD).

Methods
A total of 50 patients (26 women and 24 men) with trigeminal neuralgia (TN), hemifacial spasm (HFS), and glossopharyngeal neuralgia (GN) were examined and underwent MVD. Preoperative imaging of the neurovascular structures was performed using constructive interference in the steady state magnetic resonance (CISS MR) imaging, which consisted of 2D image slices. The 3D visualization of the neurovascular anatomy is generated after segmentaion of the CISS MR imaging in combination with direct volume rendering (DVR). The 3D representations were stored on a personal computer (PC) that was mounted on a mobile unit and transferred to the OR. During surgery, 3D visualization was applied by the surgeon with remotely controlled plasma-sterilized devices such as a wireless mouse and keyboard. The position of the 3D visualized neurovascular structures at the PC monitor was determined according to the intraoperative findings observed through the operating microscope.

Results
The system was stable during all neurosurgical procedures, and there were no operative or technical complications. Interactive adjustment of the 3D visualization guided by the view through the microscope permitted observation of the neurovascular relationships at the brainstem. Vessels covered by the cranial nerves could be noninvasively viewed by intraoperative 3D visualization. Postoperatively, the patients with TN and GN experienced pain relief, and the patients with HFS attained resolution of their facial tics. Vascular compression of nerves was explored in all 50 patients during MVD. Intraoperative 3D visualization delineated the compressing vessels and respective cranial nerves in 49 (98%) of 50 patients.

Conclusions
Interactive 3D visualization by DVR of high-resolution MR imaging data offered the opportunity for noninvasive virtual exploration of the neurovascular structures during surgery. An extended global survey of the neurovascular relationships was provided during MVD in each case. The presented method proved to be extremely advantageous for optimizing microneurosurgical procedures, supporting superior safety and improving the operative results when compared with the conventional strategy. This modality proved to be a very valuable teaching instrument and ensured the improvement of neurosurgical quality.
Classification of neurovascular compression in typical hemifacial spasm: three-dimensional visualization of the facial and the vestibulocochlear nerves
Authors: Naraghi Ramin , Tanrikulu Levent , Troescher-Weber Regina , Bischoff Barbara , Hecht Martin , Buchfelder Michael , Hastreiter Peter 
Published: December 2007

Object
In this paper, the authors introduce a method of noninvasive anatomical analysis of the facial nerve–vestibulocochlear nerve complex and the depiction of the variable vascular relationships by using 3D volume visualization. With this technique, a detailed spatial representation of the facial and vestibulocochlear nerves was obtained. Patients with hemifacial spasm (HFS) resulting from neurovascular compression (NVC) were examined.

Methods
A total of 25 patients (13 males and 12 females) with HFS underwent 3D visualization using magnetic resonance (MR) imaging with 3D constructive interference in a steady state (CISS). Each data set was segmented and visualized with respect to the individual neurovascular relationships by direct volume rendering. Segmentation and visualization of the facial and vestibulocochlear nerves were performed with reference to their root exit zone (REZ), as well as proximal and distal segments including corresponding blood vessels. The 3D visualizations were interactively compared with the intraoperative situation during microvascular decompression (MVD) to verify the results with the observed microneurosurgical anatomy.

Results
Of the 25 patients, 20 underwent MVD (80%). Microvascular details were recorded on the affected and unaffected sides. On the affected sides, the anterior inferior cerebellar artery (AICA) was the most common causative vessel. The posterior inferior cerebellar artery, vertebral artery, internal auditory artery, and veins at the REZ of the facial nerve (the seventh cranial nerve) were also found to cause vascular contacts to the REZ of the facial nerve. In addition to this, the authors identified three distinct types of NVC within the REZ of the facial nerve at the affected sides. The authors analyzed the varying courses of the vessels on the unaffected sides. There were no bilateral clinical symptoms of HFS and no bilateral vascular compression of the REZ of the facial nerve. The authors discovered that the AICA is the most common vessel that interferes with the proximal and distal portions of the facial nerve without any contact between vessels and the REZ of the facial nerve on the unaffected sides.

Conclusions
Three-dimensional visualization by direct volume rendering of 3D CISS MR imaging data offers the opportunity of noninvasive exploration and anatomical categorization of the facial nerve–vestibulocochlear nerve complex. Furthermore, it proves to be advantageous in establishing the diagnosis and guiding neurosurgical procedures by representing original MR imaging patient data in a 3D fashion. This modality provides an excellent overview of the entire neurovascular relationship of the cerebellopontine angle in each case.
Prototypical metal/polymer hybrid cerebral aneurysm clip: in vitro testing for closing force, slippage, and computed tomography artifact
Authors: Mamourian Alexander C. , Mahadevan Namrata , Reddy Nischala , Marra Steven P. , Weaver John 
Published: December 2007

Object
The aim of this study was to explore the possibility that a hybrid aneurysm clip with polymeric jaws bonded to a metal spring could provide mechanical properties comparable to those of an all-metal clip as well as diminished artifacts on computed tomography (CT) scanning.

Methods
Three clips were created, and Clips 1 and 2 were tested for mechanical properties. Clip 1 consisted of an Elgiloy spring (a cobalt-chromium-nickel alloy) bonded to carbon fiber limbs; Clip 2 consisted of an Elgiloy spring with polymethylmethacrylate (PMMA) jaws; and Clip 3 consisted of PMMA limbs identical to those in Clip 2 but bonded to a titanium spring. Custom testing equipment was set up to measure the aneurysm clip clamping forces and slippage. Clips 2 and 3 were visualized in vivo using a 64-slice CT unit, and the slices were reformatted into 3D images.

Results
According to the testing apparatus, Clip 2 had a similar closing force but less slippage than three similar commercial aneurysm clips. The artifact from the cobalt alloy spring on CT scanning largely offset the advantage of the nonmetal PMMA limbs, which created no artifact. The hybrid titanium/PMMA clip (Clip 3) created very little artifact on CT and allowed visualization of the phantom through the limbs.

Conclusions
It is feasible to build a potentially biocompatible hybrid cerebral aneurysm clip with mechanical properties that closely resemble those of conventional metallic clips. Further testing should be directed toward establishing the reliability and biocompatibility of such a clip and optimizing the contour and surface treatments of the polymer limbs.
A hypothesis of cerebral venous system regulation based on a study of the junction between the cortical bridging veins and the superior sagittal sinus
Authors: Vignes Jean-Rodolphe , Dagain Arnaud , Guérin Jean , Liguoro Dominique 
Published: December 2007

Object
The cerebral venous regulation involved in various physiological and pathological processes has received little attention. Here the authors describe the anatomy of the junction between the cortical vein and the superior sagittal sinus (SSS) and propose a new theory of cerebral venous regulation.

Methods
Ten adult human cadaveric heads (20 sides), including five specimens into which stained latex had been injected, were used for anatomical study. Formalin-fixed cadaver heads were dissected to demonstrate the cortical veins along the SSS. The characteristics of the cortical bridging veins and their openings into the SSS were established by anatomical, histological, immunohistochemical, and ultrastructural study of the junction.

Results
After their subarachnoid course, the cortical bridging veins penetrated the SSS at different points in the dura mater depending on their rostrocaudal position. The venous endothelium stretched beyond the sinus endothelium. The orientation of the collagen fibers changed at the level of the venous openings, with the luminal diameter becoming narrow and oval-shaped. The major finding was the organization of the smooth-muscle cells at the end of each cortical vein. At this site and particularly in the frontoparietal region, the vessel resembled a myoendothelial “sphincter.” The authors hypothesize that this organization is involved in cerebral venous system regulation.

Conclusions
The point of convergence between the cortical veins and the SSS is a key area. The authors also hypothesize that the myoendothelial junction acts as a smooth sphincter and that it plays a role in cerebral venous hemodynamics and pathological conditions.
Changes in sagittal alignment after restoration of lower lumbar lordosis in patients with degenerative flat back syndrome
Authors: Jang Jee-Soo , Lee Sang-Ho , Min Jun-Hong , Maeng Dae Hyeon 
Published: December 2007

Object
The authors investigate the correlation between thoracic and lumbar curves in patients with degenerative flat back syndrome, and demonstrate the predictability of spontaneous correction of the thoracic curve and sacral angle after surgical restoration of lower lumbar lordosis.

Methods
The cases of 28 patients treated with combined anterior and posterior spinal arthrodesis were retrospectively reviewed. Inclusion criteria included loss of lower lumbar lordosis resulting in sagittal imbalance. Total lumbar lordosis, thoracic kyphosis, sacral slope, and C-7 plumb line length were measured on pre- and postoperative lateral views of the whole spine. Postoperative changes in thoracic kyphosis, sacral slope, and length of the C-7 plumb line were measured and evaluated according to extent of lumbar lordosis restoration.

Results
The mean (± standard deviation) preoperative sagittal imbalance was 64.6 ± 63.2 mm, which improved to 15.8 ± 20.7 mm after surgery (p < 0.0001). The preoperative mean lumbar lordosis was 15.6 ± 14.1°, which increased to 40.3 ± 14.5° at follow-up (p < 0.0001). The preoperative mean thoracic kyphosis was 1.6 ± 10.5° and increased to 17.2 ± 12.5° at follow-up (p < 0.0001). Significant preoperative correlations existed between kyphosis and lordosis (r = 0.628, p = 0.0003), and between lordosis and sacral slope (r = 0.647, p = 0.0002). Postoperative correlations also existed between kyphosis and lordosis (r = 0.718, p < 0.0001 and r = 0.690, p < 0.0001, respectively).

Conclusions
Lower lumbar lordosis plays an important role in sagittal alignment and balance. Surgical restoration of lumbar lordosis results in predictable spontaneous correction of the thoracic curve and sacral slope in patients with degenerative flat back syndrome.
A comparison of two techniques in image-guided thoracic pedicle screw placement: a retrospective study of 37 patients and 277 pedicle screws
Authors: Lekovic Gregory P. , Potts Eric A. , Karahalios Dean G. , Hall Graham 
Published: December 2007

Object
The goal of this study was to compare the accuracy of thoracic pedicle screw placement aided by two different image-guidance modalities.

Methods
The charts of 40 consecutive patients who had undergone stabilization of the thoracic spine between January 2003 and January 2005 were retrospectively reviewed. Three patients were excluded from the study because, on the basis of preoperative findings, small pedicle diameter precluded the use of pedicle screws. Thus, a total of 37 patients had 277 screws placed with the aid of either virtual fluoroscopy or isocentric C-arm 3D navigation. The indications for surgery included trauma, degenerative disease, and tumor, and were similar in both groups. All 37 patients underwent postoperative computed tomography scanning, and an independent reviewer graded all screws based on axial, sagittal, and coronal projections for a full determination of the placement of the screw in the pedicle.

Results
The rate of unintended perforations was found to depend on pedicle diameter (p < 0.0001). There were no statistical differences between groups with regard to rate or grade of cortical perforations. Overall, the rate and grade of perforations was low, and there were no neurological or vascular complications.

Conclusions
The authors have shown that either image-guidance system may be used with a high degree of accuracy and safety. Because both systems were found to be comparably safe and accurate, the choice of image-guidance modality may be determined by the level of surgeon comfort and/or availability of the system.
The frequency and clinical significance of congenital defects of the posterior and anterior arch of the atlas
Authors: Senoglu Mehmet , Safavi-Abbasi Sam , Theodore Nicholas , Bambakidis Nicholas C. , Crawford Neil R. , Sonntag Volker K. H. 
Published: December 2007

Object
In this study the authors investigated the anatomical, clinical, and imaging features as well as incidence of congenital defects of the C-1 arch.

Methods
The records of 1104 patients who presented with various medical problems during the time between January 2006 and December 2006 were reviewed retrospectively. The craniocervical computed tomography (CT) scans obtained in these patients were evaluated to define the incidence of congenital defects of the posterior arch of C-1. In addition, 166 dried C-1 specimens and 84 fresh human cadaveric cervical spine segments were evaluated for anomalies of the C-1 arch.

Results
Altogether, 40 anomalies (2.95%) were found in 1354 evaluated cases. Of the 1104 patients in whom CT scans were acquired, 37 (3.35%) had congenital defects of the posterior arch of the atlas. The incidence of each anomaly was as follows: Type A, 29 (2.6%); Type B, six (0.54%); and Type E, two (0.18%). There were no Type C or D defects. One patient (0.09%) had an anterior arch cleft. None of the reviewed patients had neurological deficits or required surgical intervention for their anomalies. Three cases of Type A posterior arch anomalies were present in the cadaveric specimens.

Conclusions
Most congenital anomalies of the atlantal arch are found incidentally in asymptomatic patients. Congenital defects of the posterior arch are more common than defects of the anterior arch.