bluuebunny/crossref_metadata_2025_split huggingface dataset:
Use of diffusion tensor imaging to evaluate weakness
Authors: Kim Chi Heon , Chung Chun-Kee , Kim June Sic , Jahng Tae Ahn , Lee June Ho , Song In Chan 
Published: January 2008

Object
Recently, diffusion tensor (DT) imaging was introduced to demonstrate white matter tracts. However, research interest has focused on the anatomical rather than the functional aspects of this imaging modality. The authors undertook a functional analysis of DT imaging to determine the relationship between weakness and changes on DT images.

Methods
Diffusion tensor images were obtained in 23 patients with lesions located adjacent to the pyramidal tract. Patients were classified according to their motor deficit. Axial magnetic resonance image sections through the maximum tumor diameters were selected and the mean apparent diffusion coefficients (ADCs) and mean fractional anisotropies (FAs) were measured. One ovoid region of interest (ovROI) was placed in the center of the pyramidal tract and another was designed to include the whole pyramidal tract at the same axial level (wROI). To determine intraobserver variability, a single neurosurgeon measured mean ADCs and FAs four times by using these two different ROI types without knowledge of any clinical information. To determine interobserver variability, a second neurosurgeon who was also unaware of any clinical information measured the mean ADCs and FAs by using the wROI method.
The five measurements produced the same results. The mean FA at the lesion side of the pyramidal tract was significantly lower in patients with weakness (p < 0.01). Little intraobserver measurement variability occurred using the ovROI method, and no interobserver variability occurred using the wROI method.

Conclusions
Motor weakness was significantly related to a low mean FA in the pyramidal tract on the lesion side. Designing an ROI that includes the whole pyramidal tract is an easier and more reproducible method than using an ovROI method.
Gamma Knife surgery for focal brainstem gliomas
Authors: Yen Chun Po , Sheehan Jason , Steiner Melita , Patterson Greg , Steiner Ladislau 
Published: January 2008

Object
Focal tumors, a distinct subgroup of which is composed of brainstem gliomas, may have an indolent clinical course. In the past, their management involved monitoring of open-ended imaging studies and shunt placement if cerebrospinal fluid diversion was required. Nonetheless, their treatment remains a significant challenge for neurosurgeons. Gamma Knife surgery (GKS) has recently been tried as an alternative to surgical extirpation. In the present study the authors assess clinical and imaging results in 20 patients who harbored focal brainstem gliomas treated with GKS between 1990 and 2001.

Methods
There were 10 male and 10 female patients with a mean age of 19.1 years. Sixteen tumors were located in the midbrain, three in the pons, and one in the medulla oblongata. The mean tumor volume at the time of GKS was 2.5 cm3. In 10 cases a tumor specimen was obtained either by open surgery or stereotactic biopsy, securing the diagnosis of pilocytic astrocytoma in five patients and nonpilocytic astrocytoma in five others. In the remaining 10 cases, the diagnosis was based on clinical and neuroimaging findings. The prescription Gamma Knife dose varied between 10 and 18 Gy, except in three patients who were receiving a boost to a site in which external-beam radiation was previously delivered. An average of four isocenters were utilized per GKS.
Patients were followed up for a mean of 78.0 months. The tumors disappeared in four patients and shrank in 12 patients. Of these patients, one experienced transitory extrapyramidal symptoms and fluctuating impairment of consciousness (from somnolence to coma) for 6 months. Another patient whose tumor disappeared 3 years following GKS died of stroke 8 years postoperatively. The rest of the patients either remained stable or improved clinically. Tumor progression occurred in four patients; of these four, one patient developed hydrocephalus requiring a ventriculoperitoneal shunt, two showed neurological deterioration, and one 4-year-old boy died of tumor progression.

Conclusions
Gamma Knife surgery may be an effective primary treatment or adjunct to open surgery for focal brainstem gliomas.
Fusion imaging of three-dimensional magnetic resonance cisternograms and angiograms for the assessment of microvascular decompression in patients with hemifacial spasms
Authors: Satoh Toru , Onoda Keisuke , Date Isao 
Published: January 2008

Object
The precise preoperative assessment of the complex nerve–vessel relationship at the root exit zone (RExZ) of the facial nerve is important when planning microvascular decompression (MVD) in patients with hemifacial spasms. The authors have developed an imaging technique—the fusion of 3D magnetic resonance (MR) cisternography and coregistered 3D MR angiography images—that allows clear visualization of the spatial relationship between the vessels and the rootlet of the facial nerve at the brainstem.

Methods
The authors reconstructed 3D MR cisternograms and 3D MR angiograms by using a perspective volume-rendering algorithm that they applied to the volumetric data sets of the following modalities: MR cisternography (a T2-weighted 3D fast spin echo sequence) and coregistered MR angiography (a 3D time-of-flight sequence). The complex anatomical relationship between the offending vessels and the facial nerve RExZ was inspected preoperatively by examining the fusion images from various perspectives within the cerebellopontine angle cistern, within the affected facial nerve, and through the simulated surgical route. The reconstructed 3D findings of the nerve–vessel relationship were compared with the intraoperative findings. Postoperatively, the fused 3D MR imaging technique was used to confirm that microsurgical dissection and the interposed prosthesis had succeeded in maintaining the causative vessels in a position away from the RExZ.

Conclusions
The fusion of 3D MR cisternograms and 3D MR angiograms may prove useful in the pre- and postoperative assessment of MVD in patients with hemifacial spasm.
Emergency embolectomy for treatment of acute middle cerebral artery occlusion
Authors: Horiuchi Tetsuyoshi , Nitta Junpei , Sakai Keiichi , Tanaka Yuichiro , Hongo Kazuhiro 
Published: January 2008

Object
The authors evaluated the efficacy of emergency embolectomy in patients with acute middle cerebral artery occlusion (MCAO).

Methods
A retrospective review of the charts for patients undergoing embolectomy at the authors’ institution was performed. Between October 1997 and May 2004, 12 patients (mean age 70 years) with acute MCAO were treated using embolectomy. Local intraarterial fibrinolysis with urokinase was initially undertaken in eight of 12 patients. Sufficient recanalization was not achieved with fibrinolysis in any patient, and thus embolectomy was performed immediately thereafter. Recanalization by embolectomy was achieved in all patients (mean occlusion time 6 hours, 11 minutes). Each patient’s condition was evaluated on discharge. Outcomes in the 12 patients according to the Glasgow Outcome Scale were good recovery in five, moderate disability in two, severe disability in three, vegetative state in one, and death due to a cardiac complication in one. None of the 12 patients had symptomatic hemorrhagic infarction.

Conclusions
Emergency embolectomy can be performed in patients with MCAO with minimal morbidity and death. The procedure can be used to achieve good recovery even in patients in whom fibrinolysis is insufficient after acute MCAO and should be a part of the algorithm for the treatment of MCAO.
Ischemic complications associated with resection of opercular glioma
Authors: Kumabe Toshihiro , Higano Shuichi , Takahashi Shoki , Tominaga Teiji 
Published: January 2008

Object
Opercular glioma inferolateral to the hand/digit sensorimotor area can be resected safely using a neuronavigation system and functional brain mapping techniques. However, the surgery can still sometimes cause postoperative ischemic complications, the character of which remains unclear. The authors of this study investigated the occurrence of infarction associated with resection of opercular glioma and the arterial supply to this region.

Methods
The study involved 11 consecutive patients with gliomas located in the opercular region around the orofacial primary motor and somatosensory cortices but not involving either the hand/digit area or the insula, who had been treated in their department after 1997. Both pre- and postoperative diffusion-weighted magnetic resonance (MR) imaging was performed in the nine consecutive patients after 1998 to detect ischemic complications. All patients underwent open surgery for maximum tumor resection. Postoperative MR imaging identified infarction beneath the resection cavity in all patients. Permanent motor deficits associated with infarction involving the descending motor pathway developed in two patients. Cadaveric angiography showed that the distributing arteries to the corona radiata were the long insular arteries and/or medullary arteries from the opercular and cortical segments of the middle cerebral artery.

Conclusions
Subcortical resection around the upper limiting sulcus of the posterior region of the insula and wide resection in the anteroposterior and cephalocaudal directions of the opercular region were considered to be risk factors of the critical infarction. Surgeons should be aware that resection of opercular glioma can disrupt the blood supply of the corona radiata, and carries the risk of permanent motor deficits.
Intradural cranial chordoma: a rare presentation of an uncommon tumor
Authors: Roberti Fabio , Sekhar Laligam N. , Jones Robert V. , Wright Donald C. 
Published: January 2008

Object
Intracranial intradural chordomas are extremely rare lesions, and only a few cases have been reported in the neurosurgical literature. The authors performed a retrospective analysis of cases treated at their institutions. They present an illustrative surgical scenario and discuss the published literature, pathogenesis, and histopathological features as well as available follow-up data on the clinical behavior of these intradural lesions.

Methods
The authors reviewed clinical, neuroimaging, operative and follow-up data from a series of 79 chordomas treated at their institutions over the last 17 years. They found that the tumors were confined exclusively to the intradural compartment in only three cases. Staining for MIB-1 was performed to support the differential diagnosis between ecchordosis physaliphora and intradural chordoma, and in all three patients the neoplastic nature of the lesions was confirmed. None of these three cases showed recurrence of the lesion at midterm follow up.

Conclusions
Complete resection, followed by close clinical and neuroradiological follow up, is warranted in cases of intradural cranial chordoma.
Detection of cerebral ischemia in neurovascular surgery using quantitative frequency-domain near-infrared spectroscopy
Authors: Calderon-Arnulphi Mateo , Alaraj Ali , Amin-Hanjani Sepideh , Mantulin William W. , Polzonetti Chiara M. , Gratton Enrico , Charbel Fady T. 
Published: January 2008

Object
There is great value in monitoring for signs of ischemia during neurovascular procedures. Current intraoperative monitoring techniques provide real-time feedback with limited accuracy. Quantitative frequency-domain near-infrared spectroscopy (Q-NIRS) allows measurement of tissue oxyhemoglobin (HbO2), deoxyhemoglobin (HHb), and total hemoglobin (tHb) concentrations and brain tissue oxygen saturation (SO2), which could be useful when monitoring for evidence of intraoperative ischemia.

Methods
Using Q-NIRS, the authors monitored 25 neurovascular procedures including aneurysm clip placement, arteriovenous malformation resection, carotid endarterectomy, superficial temporal artery–middle cerebral artery (MCA) bypass surgery, external carotid artery–MCA bypass surgery, encephaloduromyosynangiosis, and balloon occlusion testing. The Q-NIRS technology provides measurable cerebral oxygenation values independent from those of the scalp tissue. Thus, alterations in the variables measured with Q-NIRS quantitatively reflect cerebral tissue perfusion. Bilateral monitoring was performed in all cases.
Five of the patients exhibited evidence of clinical ischemic events during the procedures. One patient suffered blood loss with systemic hypotension and developed diffuse brain edema intraoperatively, one patient suffered an ischemic event intraoperatively and developed an occipital stroke postoperatively, and one patient showed slowing on electroencephalography intraoperatively during carotid clamping; in two patients balloon occlusion testing failed. In all cases of ischemic events occurring during the procedure, Q-NIRS monitoring showed a decrease in HbO2, tHb, and SO2, and an increase in HHb.

Conclusions
Quantitative frequency-domain near-infrared spectroscopy provides quantifiable and continuous real-time information about brain oxygenation and hemodynamics in a noninvasive manner. This continuous intraoperative oxygenation monitoring is a promising method for detecting ischemic events during neurovascular procedures.
Cerebral aneurysm progression suppressed by blockage of endothelin B receptor
Authors: Sadamasa Nobutake , Nozaki Kazuhiko , Takagi Yasushi , Moriwaki Takuya , Kawanabe Yoshifumi , Ishikawa Masatsune , Hashimoto Nobuo 
Published: January 2008

Object
Cerebral aneurysm is a major cause of subarachnoid hemorrhage, but the mechanisms of its development remain unclear. Mechanical stretch has been reported to induce vascular smooth-muscle cell apoptosis via endothelin B receptors (ETBRs). The objectives of this study were to clarify the expression and localization of ETBR in cerebral aneurysms and to examine the effect of ETBR blockage on the development of experimental cerebral aneurysms.

Methods
Seventy-two rats underwent a cerebral aneurysm induction procedure and were divided into four groups according to the duration of postoperative study periods. Expression of ETBR was confirmed by reverse transcription–polymerase chain reaction and immunohistochemical analysis. The authors also studied the effect of K-8794, an oral selective antagonist of ETBR, to see whether it would influence the formation of cerebral aneurysms.
Two weeks after the aneurysm induction procedure, ETBR was rarely detected in anterior cerebral artery–olfactory artery bifurcations, but it was weakly expressed in experimental cerebral aneurysms at 1 month after the procedure, and markedly expressed at 3 months. The administration of K-8794 for 1 month after the procedure significantly reduced the number of advanced aneurysms and the number of apoptotic smooth-muscle cells.

Conclusions
These results suggest that ETBR might play a significant role in the progression of cerebral aneurysms and have the potential to improve prevention and treatment of cerebral aneurysms.
Neural injury and recovery near cortical contusions: a clinical magnetic resonance spectroscopy study
Authors: Nakabayashi Motoaki , Suzaki Shinichiro , Tomita Hiroki 
Published: January 2008

Object
Proton magnetic resonance (MR) spectroscopy can detect neural metabolic alterations noninvasively after traumatic brain injury (TBI) even in areas that appear normal. Unlike metabolic depression in diffuse TBI, focal metabolic alterations near cortical contusions in humans have not been previously investigated in a longitudinal study. The object of this study was to identify these alterations and examine their course.

Methods
At 1 week and 1 month after mild to moderate TBI involving cortical contusion, 30 patients underwent 1H MR spectroscopy examination that focused bilaterally on normal-appearing frontal and temporal white matter. Levels of N-acetylaspartate (NAA), choline (Cho) compounds, and creatine (Cr) were measured to obtain two metabolite ratios, NAA/Cr and Cho/Cr. The ratios were compared with those of 11 healthy individuals.
At 1 week after TBI, the NAA/Cr ratio was significantly lower near cortical contusions than it was in white matter remote from the injury or in controls, while the Cho/Cr ratios did not differ significantly. At 1 month, the decreased NAA/Cr ratios near contusions had increased significantly from 1 week, as had the Cho/Cr ratio.

Conclusions
Metabolic depression reflecting neural injury was apparent in subjacent normal-appearing white matter at 1 week after cortical contusion; this had normalized substantially at 1 month.
A retrospective analysis of reasons for reoperation following initially successful peripheral nerve stimulation
Authors: Ishizuka Kelly , Oaklander Anne Louise , Chiocca E. Antonio 
Published: January 2008

Object
The authors investigated the causes for surgical reexploration in patients with complex regional pain syndrome Type II who received initial relief of pain from implantation of a peripheral nerve stimulator (PNS).

Methods
The authors reviewed the charts of 11 consecutive patients who underwent a total of 27 PNS-related operations at one institution. Duration of follow up ranged from 5 days to more than 24 months. Of 11 patients who received PNS implants, seven (64%) required one or more additional surgeries to relocate the PNS because initial pain relief following stimulation was lost and not restored by changing pulse generator settings. Loss of analgesia was attributed to migration of the sutured electrode strip paddle (nine [33%] of 27 surgeries), infection (four [15%] of 27), and the need for placement in an alternative location (three [11%] of 27).

Conclusions
Although infection is attributable to surgical technique, most complications requiring repeated surgery (nine [33%] of 27) are caused by equipment design. Changes in PNS design or in implantation technique might substantially reduce the need for reoperation after PNS implantation.
Direct repair (nerve grafting), neurotization, and end-to-side neurorrhaphy in the treatment of brachial plexus injury
Authors: Haninec Pavel , Šámal Filip , Tomáš Robert , Houstava Ladislav , Dubový Petr 
Published: January 2008

Object
The authors present the long-term results of nerve grafting and neurotization procedures in their group of patients with brachial plexus injuries and compare the results of “classic” methods of nerve repair with those of end-to-side neurorrhaphy.

Methods
Between 1994 and 2006, direct repair (nerve grafting), neurotization, and end-to-side neurorrhaphy were performed in 168 patients, 95 of whom were followed up for at least 2 years after surgery. Successful results were achieved in 79% of cases after direct repair and in 56% of cases after end-to-end neurotization. The results of neurotization depended on the type of the donor nerve used. In patients who underwent neurotization of the axillary and the musculocutaneous nerves, the use of intraplexal nerves (motor branches of the brachial plexus) as donors of motor fibers was associated with a significantly higher success rate than the use of extraplexal nerves (81% compared with 49%, respectively, p = 0.003). Because of poor functional results of axillary nerve neurotization using extraplexal nerves (success rate 47.4%), the authors used end-to-side neurorrhaphy in 14 cases of incomplete avulsion. The success rate for end-to-side neurorrhaphy using the axillary nerve as a recipient was 64.3%, similar to that for neurotization using intraplexal nerves (68.4%) and better than that achieved using extraplexal nerves (47.4%, p = 0.19).

Conclusions
End-to-side neurorrhaphy offers an advantage over classic neurotization in not requiring sacrifice of any of the surrounding nerves or the fascicles of the ulnar nerve. Typical synkinesis of muscle contraction innervated by the recipient nerve with contraction of muscles innervated by the donor was observed in patients after end-to-side neurorrhaphy.
The suprapetrosal craniotomy
Authors: Ribas Guilherme Carvalhal , Rodrigues Aldo Junqueira 
Published: January 2008

Object
The primary aim of this study was to establish standard sites for bur holes that maintain constant anatomical relationships with the skull base and neural structures and can serve as the basal aspect of supratentorial temporooccipital craniotomies.

Methods
To determine cranial–cerebral relationships, the authors created bur holes in 16 adult cadaveric skulls. Three bur holes were made on each side of the skulls (32 cerebral hemispheres). The authors then introduced plastic catheters through the bur holes to evaluate pertinent cranial and neural landmarks.
The first bur hole, located anterior to the auricle of the ear, appeared to have a particular anatomical relationship with the anterior aspect of the petrous portion of the temporal bone and the most anterior aspect of the midbrain. The second bur hole, whose base was located 1 cm above the interface of the parietomastoid and squamous sutures, had a particular relationship with the posterior border of the petrous portion of the temporal bone and with the posterior aspect of the midbrain. The third bur hole, whose base was located 1 cm above the asterion, was mostly supratentorial and particularly related to the preoccipital notch.

Conclusions
The preauricular bur hole and the bur hole whose base was located 1 cm above the interface of the parietomastoid and squamous sutures delimit anteriorly and posteriorly the external projection of the petrous bone and the midbrain. The middle fossa floor is located anterior to the site of the preauricular bur hole, and the superior surface of the tentorium is posterior to the bur hole located above the parietomastoid–squamous suture interface. Together with the bur hole whose base is located above the asterion, these bur holes can be considered standards for temporooccipital craniotomies.
Lack of utility of arteriojugular venous differences of lactate as a reliable indicator of increased brain anaerobic metabolism in traumatic brain injury
Authors: Poca Maria A. , Sahuquillo Juan , Vilalta Anna , Garnacho Angel 
Published: January 2008

Object
Ischemic lesions are highly prevalent in patients with traumatic brain injuries (TBIs) and are the single most important cause of secondary brain damage. The prevention and early treatment of these lesions is the primary aim in the modern treatment of these patients. One of the most widely used monitoring techniques at the bedside is quantification of brain extracellular level of lactate by using arteriojugular venous differences of lactate (AVDL). The purpose of this study was to determine the sensitivity, specificity, and predictive value of AVDL as an indicator of increases in brain lactate production in patients with TBIs.

Methods
Arteriojugular venous differences of lactate were calculated every 6 hours using samples obtained though a catheter placed in the jugular bulb in 45 patients with diffuse head injuries (57.8%) or evacuated brain lesions (42.2%). Cerebral lactate concentration obtained with a 20-kD microdialysis catheter implanted in undamaged tissue was used as the de facto gold standard.
Six hundred seventy-three AVDL determinations and cerebral microdialysis samples were obtained simultaneously; 543 microdialysis samples (81%) showed lactate values greater than 2 mmol/L, but only 21 AVDL determinations (3.1%) showed an increase in brain lactate. No correlation was found between AVDL and cerebral lactate concentration (ρ = 0.014, p = 0.719). Arteriojugular venous differences of lactate had a sensitivity and specificity of 3.3 and 97.7%, respectively, with a false-negative rate of 96.7% and a false-positive rate of 2.3%.

Conclusions
Arteriojugular venous differences of lactate do not reliably reflect increased cerebral lactate production and consequently are not reliable in ruling out brain ischemia in patients with TBIs. The clinical use of this monitoring method in neurocritical care should be reconsidered.