bluuebunny/crossref_metadata_2025 huggingface dataset:
Low-dose radiosurgery for large vestibular schwannomas: long-term results of functional preservation
Authors: Inoue Hiroshi K.
Published: May 2009

Object.The author conducted a study to assess the long-term results obtained in patients who underwent GKS for large vestibular schwannomas (> cochlear nerve functions were evaluated.

Methods.Twenty consecutive large tumors in 18 patients (including two cases of neurofibromatosus Type 2 [NF2]) were followed for more than 6 years. There were eight tumors that were more than 4 cm in maximum diameter. Microsurgery had already been performed prior to GKS in 11 patients (nine recurrent and two residual tumors).

Four patients (including one with NF2) died during the follow-up period of other diseases or by accident. Fourteen of 15 tumors were stable or decreased in size. Microsurgery was performed in one patient 2 years after radiosurgery. Facial nerve function was preserved in all patients and hearing preserved in four of five patients with cochlear nerve function prior to radiosurgery. No adverse effects of radiosurgery have been observed to date.

Conclusions.Gamma knife surgery seems to have a place in the low-dose treatment of selected large vestibular schwannoma in patients with a reasonable chance of retaining facial function and pretreatment hearing level. Patients with severe brainstem compression should first be undergo microsurgery.
Gamma knife surgery for brain metastases in patients harboring four or more lesions: survival and prognostic factors
Authors: Nam Taek-Kyun , Lee Jung-Il , Jung Young-Jo , Im Yong-Seok , An Hee-Ye , Nam Do-Hyun , Park Kwan , Kim Jong-Hyun
Published: May 2009

Object.This study was performed to evaluate the role of gamma knife surgery (GKS) in patients with a large number (four or more) of metastatic brain lesions.

Methods.The authors retrospectively reviewed the outcome in 130 patients who underwent GKS for metastatic lesions. Eighty-four patients presented with one to three lesions (Group A) and 46 presented with four or more lesions (Group B). The overall median survival time after GKS was 35 weeks. The median survival time in Group A (48 weeks) was significantly longer (p = 0.005) than the survival time in Group B (26 weeks). The recursive partitioning analysis (RPA) class was the only significant prognostic factor identified in multivariate analysis. The median survival for patients in RPA Classes I, II, and III was 72, 48, and 19 weeks, respectively, in Group A and 36 and 13 weeks for Classes II and III in Group B. The number of lesions, tumor volume, whole brain radiotherapy, primary tumor site, age, and sex did not affect survival significantly.

Conclusions.It is suggested that GKS provides an increase in survival time even in patients with a large number (four or more) of metastatic lesions. Concerning the selection of patients for GKS, RPA class should be considered as the most important factor and multiplicity of the lesions alone should not be a reason for withholding GKS.
Pineal tumors: analysis of treatment results in 20 patients
Authors: Amendola Beatriz E. , Wolf Aizik , Coy Sammie R. , Amendola Marco A. , Eber Daryl
Published: May 2009

Object. The authors evaluate their results when using gamma knife surgery (GKS) in the management of patients with tumors in the pineal region.

Methods. This is a retrospective clinical evaluation of 20 patients with primary tumors of the pineal region treated with GKS from November 1994 through August 2003. There were 13 germ cell tumors, two pineoblastomas, two low-grade gliomas, one primitive neuroectodermal tumor, one teratoma, and one pineocytoma. There were 10 male and 10 female patients. Their median age was 15.5 years (range 5–71 years). The median margin dose was 11 Gy (range 8–20 Gy). The median target volume was 3.1 cm3 (range 0.1–49.9 cm3). Five patients received sequential systemic chemotherapy and four underwent adjuvant conventional radiation therapy. Seventeen (85%) of 20 patients are alive with a median survival of 30.4 months (range 0–-85.7 months). Two patients required retreatment. Three patients died: one of unrelated causes, one who presented with extensive local disease, and the other of meningeal carcinomatosis with local control of the primary tumor. No complications from GKS were noted.

Conclusions. This initial experience suggests that GKS is a valuable treatment modality for the management of pineal region tumors. This technique offers excellent local tumor control and minimal patient morbidity, allowing for immediate use of systemic chemotherapy and/or conventional radiation if indicated.
Gamma knife surgery for trigeminal neuralgia: improved initial response with two isocenters and increasing dose
Authors: Alpert Tracy E. , Chung Chung T. , Mitchell Lisa T. , Hodge Charles J. , Montgomery Craig T. , Bogart Jeffrey A. , Kim Daniel Y-J. , Bassano Danel A. , Hahn Seung S.
Published: May 2009

Object.The authors sought to evaluate the initial response of trigeminal neuralgia (TN) to gamma knife surgery (GKS) based on the number of shots delivered and radiation dose.

Methods.Between September 1998 and September 2003, some 63 patients with TN refractory to medical or surgical management underwent GKS at Upstate Medical University. Ten patients had multiple sclerosis and 25 patients had undergone prior invasive treatment. Gamma knife surgery was delivered to the trigeminal nerve root entry zone in one shot in 27 patients or two shots in 36 patients. The radiation dose was escalated to less than or equal to 80 Gy in 20 patients, 85 Gy in 21 patients, and greater than or equal to 90 Gy in 22 patients. Pain before and after GKS was assessed using the Barrow Neurological Institute Pain Scale and the improvement score was analyzed as a function of dose grouping and number of shots.

Sixty patients were available for evaluation, with an initial overall and complete response rate of 90% and 27%, respectively. There was a greater improvement score for patients who were treated with two shots compared with one shot, mean 2.83 compared with 1.72 (p < 0.001). There was an increased improvement in score at each dose escalation level: less than or equal to 80 Gy (p = 0.017), 85 Gy (p < 0.001), and greater than or equal to 90 Gy (p < 0.001). Linear regression analysis also indicated that there was a greater response with an increased dose (p = 0.021). Patients treated with two shots were more likely to receive a higher dose (p < 0.001). There were no severe complications. Five patients developed mild facial numbness.

Conclusions.Gamma knife surgery is an effective therapy for TN. Initial response rates appear to correlate with the number of shots and dose.
Volume reduction in meningiomas after gamma knife surgery
Authors: Feigl Guenther C. , Bundschuh Otto , Gharabaghi Alireza , Samii Madjid , Horstmann Gerhard A.
Published: May 2009

Object.The purpose of this study was to evaluate the volume-reducing effects of gamma knife surgery (GKS) of meningiomas with and without previous surgical treatment.

Methods.A group of 127 patients with a mean age of 57.1 years (range 9–81 years) with 142 meningiomas (128 World Health Organization Grade I and 14 Grade II) were included in this study. The management strategy reduces tumor volume with surgery when necessary (81 patients). Stereotactic GKS with a Gamma Knife model C was performed in all tumors of suitable size. Magnetic resonance imaging follow-up examinations with volumetric tumor analysis was performed 6 months after treatment and annually thereafter.

The mean tumor volume was 5.9 cm3(range < 5 to > 40 cm3). The mean follow-up time after GKS was 29.3 months (range 11–61 months). The mean prescription dose was 13.8 Gy (range 10–18 Gy). A reduction in volume occurred in 117 (82.4%) of all tumors, and in 20 tumors (14.1%) growth ceased. The overall tumor control rate of 96.4%. The mean volume reduction achieved with GKS was more than 46.1%. Only five tumors (3.5%) showed a volume increase.

Conclusions.Gamma knife surgery was effective in reducing meningioma volume at short-term follow up. Further studies are needed to examine the development of these findings over a longer period.
Gamma knife thalamotomy for movement disorders: evaluation of the thalamic lesion and clinical results
Authors: Ohye Chihiro , Shibazaki Tohru , Sato Sumito
Published: May 2009

Object.The authors studied the effects of gamma knife thalamotomy (GKT) on Parkinson disease-related tremor and essential tremor before and after reloading of radioactive cobalt.

Methods.Based on experience in stereotactic thalamotomy aided by depth microrecording, the target was located at the lateral border of the thalamic ventralis intermedius nucleus (VIM). For more precise targeting, the percentage representation of the thalamic VIM in relation to the entire thalamic length is useful. The location of the target was determined on magnetic resonance (MR) imaging and computerized tomography scanning. A maximum dose of 130 Gy was delivered to the target by using a single isocenter with the 4-mm collimator. In more recent cases, a systematic follow-up examination was performed at 3, 6, 12, 18, and 24 months after GKT.

Since 1993, the authors have treated 70 patients with PD. Throughout the series the same dosimetric technique has been used. The course after GKT was compared between the 25 cases with PD treated before reloading and the 35 cases treated after reloading. In the majority (80–85%) treated after reloading, tremor and rigidity were reduced around 6 months after GKT. In the cases treated before reloading this effect took approximately 1 year. The thalamic reaction on MR imaging showed the same two lesion types in both series: a restricted and a diffuse. After reloading the restricted lesion was more frequent and the lesion volume was smaller.

Conclusions.The shorter delay in clinical improvement and smaller lesion size may be related to an increased radiation dose.
Prolonged survival in a subgroup of patients with brain metastases treated by gamma knife surgery
Authors: Yu C. P. , Cheung Joel Y. C. , Chan Josie F. K. , Leung Samuel C. L. , Ho Robert T. K.
Published: May 2009

Object.The authors analyzed the factors involved in determining prolonged survival (≥ 24 months) in patients with brain metastases treated by gamma knife surgery (GKS).

Methods.Between 1995 and 2003, a total of 116 patients underwent 167 GKS procedures for brain metastases. There was no special case selection. Smaller and larger lesions were treated with different protocols. The mean patient age was 56.9 years, the mean number of initial lesions was 3.15, and the mean lesion volume was 10.45 cm.3The mean follow-up time was 9.2 months.

The median patient survival was 8.68 months. One-, 2-, 3-, 4-, and 5-year actuarial survival rates were 31.8%, 19.8%, 14.6%, 7.7%, and 6.9%, respectively. Patient age, number of lesions at presentation, and lesion volume had no influence on patient survival. Twenty-three (19.8%) patients survived for 24 months or more. Certain factors were associated with increased survival time. These were stable primary disease (21 of 23 patients), a long latency between diagnosis of the primary tumor and the occurrence of brain metastases (mean 28.4 months, median 16 months), absence of third-organ involvement, and repeated local procedures. Ten patients underwent repeated GKS (mean 3.4 per patient). Seven patients required open surgery for local treatment failures (recurrence or radiation necrosis). Two patients had both. Fifteen patients underwent repeated procedures.

Conclusions.Aggressive local therapy with GKS, repeated GKS, and GKS plus surgery can achieve increased survival in a subgroup of patients with stable primary disease, no third-organ involvement, and long primary-brain secondary intervals.
Initial experience with gamma knife surgery for endocrine ophthalmopathy
Authors: Antico Julio C. , Crovetto Luis , Tenca Eduardo , Artes Carlos
Published: May 2009

Object. The aim of this study was to evaluate both the effectiveness and safety of the treatment of endocrine ophthalmopathy with gamma knife surgery (GKS).

Methods. Five patients were included in a prospective study designed to assess the results of GKS of endocrine ophthalmopathy secondary to Graves disease. All the patients completed a 2-year follow-up period. During this period, the patients were evaluated both clinically and by means of additional methods, including computerized tomography and magnetic resonance imaging studies. The minimum dose delivered to the 50% isodose line was 6.5 Gy in all the patients.

In all cases, a clinical improvement was observed. The best effect was seen in symptom regression related to soft-tissue involvement. No treatment-related side effects were detected.

Conclusions. In light of the results obtained the authors consider that GKS may be a safe and effective way to treat endocrine ophthalmopathy.
Gamma knife surgery for refractory postherpetic trigeminal neuralgia: targeting in one session both the retrogasserian trigeminal nerve and the centromedian nucleus of the thalamus
Authors: Keep Marcus F. , DeMare Paul A. , Ashby Lynn S.
Published: May 2009

Object.The authors tested the hypothesis that two targets are needed to treat postherpetic trigeminal neuralgia (TN): one in the trigeminal nerve for the direct sharp pain and one in the thalamus for the diffuse burning pain.

Methods.Three patients with refractory postherpetic TN were treated with gamma knife surgery (GKS) through a novel two-target approach. In a single treatment session, both the trigeminal nerve and centromedian nucleus were targeted. First, the trigeminal nerve, ipsilateral to the facial pain, was treated with 60 to 80 Gy. Second, the centromedian nucleus was localized using standard coordinates and by comparing magnetic resonance images with a stereotactic atlas. A single dose of 120 to 140 Gy was delivered to the target point with a single 4-mm isocenter. Patients were followed clinically and with neuroimaging studies. Pain relief was scored as excellent (75–100%), good (50–75%), poor (25–50%), or none (0–25%). Follow up ranged from 6 to 53 months.

There were no GKS-related complications. Two patients died of unrelated medical illnesses but had good or excellent pain relief until death. One patient continues to survive with 44 months follow up and no decrease in pain intensity, but with a decreased area of pain.

Conclusions.Combined GKS of the centromedian nucleus and trigeminal nerve in a single treatment session is feasible and safe, and the effect was promising. A larger study is required to confirm and expand these results.
Gamma knife surgery for atypical meningiomas
Authors: Huffmann Beate C. , Reinacher Peter C. , Gilsbach Joachim M.
Published: May 2009

Object. Complete resection is the optimal treatment for atypical meningiomas (AMs) but its feasibility depends on the tumor site. The object of this study was to assess the effect of gamma knife surgery (GKS) on AM.

Methods. In 15 patients 21 AMs were treated by GKS. Four patients had residual lesions and 10 patients had recurrent tumors after one or more microsurgical interventions. Three patients were treated twice with GKS because of tumor tissue outside the treatment volume, either at the margin or at a distant location. The median clinical and neuroimaging follow-up period was 35 months (range 21–67 months).

Ten tumors shrank 6 to 12 months after GKS, 10 remained stable, and one grew. Between 18 and 36 months after GKS, four patients had a distant recurrence, and two had a margin recurrence. In one of these cases, an additional local recurrence was demonstrated 1 year later, and the patient underwent standard radiotherapy. No patient suffered persistent adverse effects after radiosurgery.

Conclusions. After early tumor shrinkage, high recurrence rates were demonstrated both at the treatment margin and at distant locations in cases treated for AM. There was only one recurrence within the GKS radiation field. For small- and medium-sized AMs GKS may be a safe adjunct to other treatment modalities.
Tumor recurrence and survival following gamma knife surgery for brain metastases
Authors: Mindermann Thomas
Published: May 2009

Object.The authors evaluated prognostic factors for tumor recurrence and patient survival following gamma knife surgery (GKS) for brain metastasis.

Methods.A retrospective review of 101 patient charts was undertaken for those patients treated with GKS for brain metastases from 1994 to 2001.

Recurrence rates of brain metastasis following GKS depended on the duration of patient survival. Long-term survival was associated with a higher risk of tumor recurrence and shorter-term survival was associated with a lower risk. The duration of survival following GKS for brain metastases seems to be characteristic of the primary disease rather than the cerebral disease.

Conclusions.Recurrence rates of brain metastasis following GKS are related to duration of survival, which is in turn mostly dependent on the nature and course of the primary tumor.
Hemodynamic changes due to stent placement in bifurcating intracranial aneurysms
Authors: Cantón Gádor , Levy David I. , Lasheras Juan C.
Published: May 2009

Object

The aim of this study was to measure changes in intraaneurysm flow dynamics and mechanical stresses resulting from the placement of Neuroform stents in bifurcating intracranial aneurysm models.

Methods

A digital particle image velocimetry (DPIV) system was used to measure the pulsatile velocity and shear stress fields within the aneurysm and at the aneurysm neck—parent artery interface. The DPIV system provides an instantaneous two-dimensional measurement of the temporal and spatial variations of the velocity vector field of the flow inside the aneurysm pouch and the parent vessel, providing information on both the temporal and spatial variations of the velocity field during the entire cardiac cycle. The corresponding shear stress field was then computed from the velocity field data. A flexible silicone model of bifurcating intracranial aneurysms was used. Two Neuroform stents with a 60- to 65-µm strut thickness and an 11% metal/artery ratio were placed in a Y-configuration, and measurements were obtained after placing the stents.

Conclusions

Two three-dimensional vortices of different strengths persisted within the aneurysm during the entire cardiac cycle. The peak velocity and strength of these vortices were reduced after placing the two bifurcating stents. The effect of placing the Neuroform stent across the neck of a bifurcating intracranial aneurysm was shown to reduce the magnitude of the velocity of the jet entering the sac by as much as 11%. Nevertheless, the effect of the stents was particularly noticeable at the end of the cardiac cycle, when the residual vorticity and shear stresses inside the sac were decreased by more than 40%.
Combined surgical and endovascular treatment of a spontaneous diploic arteriovenous fistula
Authors: Burger Ingrid M. , Tamargo Rafael J. , Broussard Jennifer , Gailloud Philippe
Published: May 2009

✓The authors report on the case of a 28-year-old woman presenting with an intraosseous arteriovenous fistula (AVF) located in the left parietal bone. The fistula was formed by direct arteriovenous shunts connecting branches of the left middle meningeal and superficial temporal arteries with a parietal diploic vein. Drainage occurred through both the external and internal jugular venous systems. Therapy consisted of combined surgical and endovascular approaches. The results of a pathological examination of the resected AVF showed mild enlargement of the diploic space. The angiographic appearance, pathological anatomy, and treatment of this rare lesion are discussed, as is a possible relationship between diploic AVFs and the development of aneurysm bone cysts.
Use of side branch in saphenous vein interposition graft for high-flow EC/IC bypass procedures
Authors: Rivet Dennis J. , Wanebo John E. , Roberts Gareth A. , Dacey Ralph G.
Published: May 2009

✓ Saphenous vein (SV) interposition grafts are often used for high-flow extracranial—intracranial bypass procedures. During these procedures, it is essential to remove air and debris from the graft and to evaluate blood flow through the graft after it has been anastomosed to other cortical vessels.

In this paper, the authors describe the preservation of a large side branch on the proximal end of the SV. This side branch can be used to flush out air and debris from the graft and to evaluate blood flow during revascularization.
Linear accelerator surgery for meningiomas
Authors: Friedman William A. , Murad Gregory J. , Bradshaw Patrick , Amdur Robert J. , Mendenhall William M. , Foote Kelly D. , Bova Frank J.
Published: May 2009

Object. In this paper the authors review the results of a single-center experience in the use of linear accelerator (LINAC) surgery for radiosurgical treatment of meningiomas.

Methods. A retrospective analysis of all patients treated with LINAC surgery for meningiomas between May 1989 and December 2001 was performed. All patients participated in follow-up review for a minimum of 2 years, and no patients were excluded. Two hundred ten patients were treated during the study interval.

The actuarial local control rate for benign tumors was 100% at both 1 and 2 years, and 96% at 5 years. The actuarial local control rate for atypical tumors was 100% at 1 year, 92% at 2 years, and 77% at 5 years; and that for malignant tumors was 100% at both 1 and 2 years, and only 19% at 5 years. Of the 210 patients 13 (6.2%) experienced temporary radiation-induced complications, and only five (2.3%) experienced permanent complications. In all patients with a permanent complication the histological characteristics of the meningioma were malignant.

Conclusions. Linear accelerator surgery produced high local control rates and very low rates of permanent morbidity in patients harboring benign meningiomas.
Case—control study of stereotactic radiosurgery for recurrent glioblastoma multiforme
Authors: Mahajan Anita , McCutcheon Ian E. , Suki Dima , Chang Eric L. , Hassenbusch Samuel J. , Weinberg Jeffrey S. , Shiu Almon , Maor Moshe H. , Woo Shiao Y.
Published: May 2009

Object. The role of stereotactic radiosurgery (SRS) for recurrent glioblastoma multiforme (GBM) was evaluated in a case—control study.

Methods. All patients who underwent SRS for recurrent GBM before March 2003 formed the case group. A control group of patients who did not undergo SRS was created from an institutional database, and each case was matched for known prognostic factors in GBM. The medical and neuroimaging records of all the patients were reviewed, and survival and treatment outcomes were recorded.

The case and control groups were well matched with regard to demographics and pre-SRS interventions. In the control group, the date on which magnetic resonance imaging identified a recurrent lesion that would have been eligible for SRS was deemed the “SRS” date. The number of surgeries performed in the control group was statistically higher than that in the case group. The median duration of overall survival from diagnosis was 26 months in the case group and 23 months in the control group. From the date of SRS or “SRS”, the median duration of survival was 11 months in the case group and 10 months in the control group, a difference that was not statistically significant.

Conclusions. It appears that a subgroup of patients with GBMs has a higher than expected median survival duration despite the initial prognostic factors. In patients with localized recurrences, survival may be prolonged by applying aggressive local disease management by using either SRS or resection to equal advantage.
Psychiatric symptoms in patients with Parkinson disease presenting for deep brain stimulation surgery
Authors: Voon Valerie , Saint-Cyr Jean , Lozano Andres M. , Moro Elena , Poon Yu Yan , Lang Anthony E.
Published: May 2009

Object. Postoperative psychiatric symptoms have been associated with subthalamic deep brain stimulation (DBS) for Parkinson disease (PD), and preoperative psychiatric vulnerability, the effects of surgery, stimulation, medication changes, and psychosocial adjustment have been proposed as causative factors. The variables involved in whether preoperative psychiatric symptoms improve or worsen following surgery are not yet known. In the present study, preoperative psychiatric symptoms were systematically assessed in patients with PD presenting for routine preoperative psychiatric assessment.

Methods. Forty consecutive patients with PD presenting for DBS were interviewed using the Mini International Neuropsychiatric Inventory. Current depressive symptoms were quantified using clinician- and patient-rated depression scales. Seventy-eight percent of patients had at least one lifetime or current Axis I psychiatric diagnosis. The prevalence of depression was 60% (95% confidence interval [CI] 45–85), psychosis 35% (95% CI 25–50), and anxiety 40% (95% CI 25–55). These prevalence rates were comparable to or greater than those in the general population of patients with PD. Twenty-three percent of patients required psychiatric treatment for current symptoms prior to being considered eligible for DBS.

Conclusions. As part of the selection process for surgery, members of the study population were chosen for their lack of overt dementia or other active disabling psychiatric symptomatology. The incidence rates of psychiatric disorders, including those diseases occurring in the general population affected with PD, were greater than expected. Data in the present study lead one to question the reliability of patient-rated depression scales as the sole instrument for assessing depression. The authors highlight the need for evidence-based guidelines in the management of these preoperative symptoms as well as the involvement of psychiatric personnel in the assessment and management of these symptoms.
Characterization and correction of distortions in stereotactic magnetic resonance imaging for bilateral subthalamic stimulation in Parkinson disease
Authors: Menuel Carole , Garnero Line , Bardinet Eric , Poupon Fabrice , Phalippou Daniel , Dormont Didier
Published: May 2009

Object. High-frequency stimulation of the subthalamic nucleus (STN) is effective for treating refractory idiopathic Parkinson disease (PD). In stereotactic conditions magnetic resonance (MR) imaging is used by many teams to perform preoperative targeting of the STN. The goal of this study was to analyze and correct the geometrically observed MR imaging acquisitions used for targeting of the STN.

Methods. A dedicated phantom of known geometry was used. The authors calculated existing shifts between measured points and theoretically defined points on the same T1- and T2-weighted sequences used to target the STN. A shifting volume was built to correct the phantom images and images acquired preoperatively in 13 patients with PD. A quantitative study of the correction was conducted using the phantom images and acquisitions acquired in these patients. To quantify the distortion corrections, the authors segmented the lateral ventricles and calculated the overlap of the corrected and uncorrected values between T1 and T2 segmentation.

The authors found that the distortions were greater in the direction of slice selection and frequency encoding and weaker on three-dimensional T1-weighted acquisitions. On T2-weighted acquisitions, the maximum shifts were 2.19 mm in the frequency-encoding direction and 3.81 mm in slice selection. The geometrical distortion was significantly reduced and smaller than pixel size after distortion correction. Assessment of the patients' scans showed that the mean ventricular overlap was 76% before and 94% after correction.

Conclusions. The authors found that significant distortions can be observed on T2-weighted images used to demonstrate the STN. These distortions can be corrected using appropriate software.
Intraoperative monitoring of blood flow insufficiency during surgery of middle cerebral artery aneurysms
Authors: Horiuchi Kazuomi , Suzuki Kyouichi , Sasaki Tatsuya , Matsumoto Masato , Sakuma Jun , Konno Yutaka , Oinuma Masahiro , Itakura Takeshi , Kodama Namio
Published: May 2009

Object. The usefulness of motor evoked potential (MEP) monitoring to detect blood flow insufficiency (BFI) in the cortical branches of the middle cerebral artery (MCA) and lenticulostriate arteries (LSAs) during MCA aneurysm surgery was investigated based on the correlation between MEP and somatosensory evoked potential (SEP) monitoring.

Methods. Fifty-three patients with MCA aneurysms underwent surgery accompanied by intraoperative MEP and SEP monitoring. There was no postoperative motor paresis in 43 patients in whom MEP and SEP results remained unchanged. In the other 10 patients, nine manifested transient MEP changes; in five of these, SEP changes did not occur. The transient MEP changes were thought to be attributable to BFI of the MCA cortical branches in two patients, the LSA in three, and either the MCA branches or the LSA in four patients. Of these nine patients, six did not present with postoperative motor paresis; transient motor paresis was recognized in the other three. In the 10th patient, MEP waves disappeared and did not recover. This patient's SEPs remained at 70% of the control level, and he developed severe hemiparesis. A postoperative computerized tomography scan revealed a new low-density area in the corona radiata and putamen.

Conclusions. Blood flow insufficiency in both the LSA and MCA cortical branches that perfuse the corticospinal tract can be detected by intraoperative MEP monitoring. Somatosensory evoked potential monitoring is not reliable enough to detect BFI in the MCA branches and the LSAs.
Reduction in levels of matrix metalloproteinases and increased expression of tissue inhibitor of metalloproteinase—2 in response to mild hypothermia therapy in experimental stroke
Authors: Lee Jong Eun , Yoon Yone Jung , Moseley Michael E. , Yenari Midori A.
Published: May 2009

Object. Mild hypothermia is a robust neuroprotectant, and the results of prospective clinical trials have indicated that it may improve neurological outcome in certain instances. One aspect of this protection has been associated with the prevention of blood—brain barrier (BBB) disruption. Matrix metalloproteinases (MMPs) have been implicated in BBB disruption because they can degrade the extracellular matrix. In this study the authors explored the relationship between hypothermia and MMPs and whether BBB preservation resulting from mild hypothermia therapy is due to alterations in MMP expression.

Methods. Rats were subjected to middle cerebral artery occlusion for 2 hours; the animals were maintained in a state of normothermia or mild hypothermia (33°C) immediately after the onset of ischemia. The animals' brains were collected 2, 6, and 24 hours after ischemia began. Contrast-enhanced T1-weighted magnetic resonance imaging was performed at 24 hours to assess the extent of BBB disruption.

Consistent with prior reports, areas of BBB disruption detected on T1-weighted images were smaller in the brains of rats maintained in a state of hypothermia (normothermia group 8.6 ± 3% of the brain; hypothermia group 0.2 ± 0.1% of the brain; p < 0.01). Expression of both MMP-2 and MMP-9 at the transcriptional and translational levels was reduced in hypothermic brains at 6 hours and 24 hours after ischemic injury. Matrix metalloproteinase—9 was primarily localized to cells of monocytic origin but was also observed in neurons and astrocytes. Matrix metalloproteinase—2 was found in some neurons and astrocytes but not in inflammatory cells. In addition, hypothermia increased the levels of the endogenous MMP inhibitor, tissue inhibitor of metalloproteinases—2.

Conclusions. The authors conclude that mild hypothermia attenuates BBB disruption, decreases MMP expression, and suppresses MMP activity.
Diffuse axonal injury in mild traumatic brain injury: a diffusion tensor imaging study
Authors: Inglese Matilde , Makani Sachin , Johnson Glyn , Cohen Benjamin A. , Silver Jonathan A. , Gonen Oded , Grossman Robert I.
Published: May 2009

Object. Diffuse axonal injury (DAI) is a major complication of traumatic brain injury (TBI) that leads to functional and psychological deficits. Although DAI is frequently underdiagnosed by conventional imaging modalities, it can be demonstrated using diffusion tensor imaging. The aim of this study was to assess the presence and extent of DAI in patients with mild TBI.

Methods. Forty-six patients with mild TBI and 29 healthy volunteers underwent a magnetic resonance (MR) imaging protocol including: dual—spin echo, fluid-attenuated inversion recovery, T2-weighted gradient echo, and diffusion tensor imaging sequences. In 20 of the patients, MR imaging was performed at a mean of 4.05 days after injury. In the remaining 26, MR imaging was performed at a mean of 5.7 years after injury. In each case, mean diffusivity and fractional anisotropy were measured using both whole-brain histograms and regions of interest analysis. No differences in any of the histogram-derived measures were found between patients and control volunteers. Compared with controls, a significant reduction of fractional anisotropy was observed in patients' corpus callosum, internal capsule, and centrum semiovale, and there were significant increases of mean diffusivity in the corpus callosum and internal capsule. Neither histogram-derived nor regional diffusion tensor imaging metrics differed between the two groups.

Conclusions. Although mean diffusivity and fractional anisotropy abnormalities in these patients with TBI were too subtle to be detected with the whole-brain histogram analysis, they are present in brain areas that are frequent sites of DAI. Because diffusion tensor imaging changes are present at both early and late time points following injury, they may represent an early indicator and a prognostic measure of subsequent brain damage.
Long-term reendothelialization of excimer laser—assisted nonocclusive anastomoses compared with conventionally sutured anastomoses in pigs
Authors: Streefkerk Henk Johan N. , Kleinveld Sanne , Koedam Ester L. G. E. , Bulder Marcel M. M. , Meeldijk Hans D. , Verdaasdonk Ruud M. , Mansvelt Beck Rik J. , van der Zwan Bart , Tulleken Cornelis A. F.
Published: May 2009

Object. In contrast to conventional anastomosis methods, the excimer laser—assisted nonocclusive anastomosis (ELANA) technique involves a platinum ring and intima—adventitia apposition with a rim of medial and adventitial layers exposed to the bloodstream. The authors assessed the reendothelialization of porcine carotid arteries through ELANA compared with conventional anastomosis by using scanning electron microscopy.

Methods. In 28 pigs a bypass with one ELANA and one conventional anastomosis was made on the left common carotid artery. All patent anastomoses were evaluated intraoperatively with the aid of an ultrasonographic flowmeter and postoperatively by using scanning electron microscopy at 2 weeks, 2 months, 3 months, and 6 months thereafter. Twenty-four of 28 bypasses (48 of 56 end-to-side anastomoses) were fully patent at the time of evaluation. On scanning electron microscopic evaluation of the bypasses, all 48 patent anastomoses showed complete reendothelialization, including all 24 ELANAs in which the endothelium covered the rim and the laser-ablated edge completely. No endothelial difference was observed between conventional anastomoses and ELANAs, aside from the obvious anatomical differences like the platinum ring, which had been completely covered with endothelium. At 6 months postsurgery, remodeling of the ELANA was observed, leaving the ring covered with a layer of endothelium as the most narrow part of the anastomosis.

Conclusions. In long-term experiments, ELANA allows reendothelialization comparable to that achieved with conventional anastomosis. Considering its nonocclusive and high-flow characteristics, the ELANA technique is preferable in cerebral revascularization procedures.
Microsurgical anatomy of the interpeduncular cistern and related arachnoid membranes
Authors: Lü Jian , Zhu Xianli
Published: May 2009

Object. The goal of this study was to investigate the microsurgical anatomy of the interpeduncular cistern and related arachnoid membranes.

Methods. The interpeduncular cistern and related arachnoid membranes were studied in eight Han Chinese adult human cadaveric brains with the aid of an operating microscope.

The interpeduncular cistern is one area in the cranial cavity in which the arachnoid membranes and trabeculae are extremely luxuriant and complicated. The Liliequist membrane, the medial pontomesencephalic membrane, and the lateral pontomesencephalic membranes form the walls of the interpeduncular cisterns. The basilar artery (BA) bifurcation membrane, posterior perforated membrane, and arachnoid trabeculae fill the cistern. These arachnoid membranes and trabeculae adhere to the hypothalamus, brainstem, and oculomotor nerves, and bind the bifurcation of the BA, posterior cerebral arteries, superior cerebellar arteries, posterior communicating arteries, and their perforating branches.

Conclusions. Arachnoid membranes and trabeculae complicate the exposure and dissection of lesions within the interpeduncular cistern. All arachnoid membranes and trabeculae should be dissected and incised sharply during surgical procedures. The BA bifurcation membrane and the posterior perforated membrane must be incised after opening the Liliequist membrane for sufficient exposure of deep structures within the interpeduncular cistern.
Preoperative and postoperative mapping of cerebrovascular reactivity in moyamoya disease by using blood oxygen level—dependent magnetic resonance imaging
Authors: Mikulis David J. , Krolczyk Gregory , Desal Hubert , Logan William , deVeber Gabrielle , Dirks Peter , Tymianski Michael , Crawley Adrian , Vesely Alex , Kassner Andrea , Preiss David , Somogyi Ron , Fisher Joseph A.
Published: May 2009

Object. The ability to map cerebrovascular reactivity (CVR) at the tissue level in patients with moyamoya disease could have considerable impact on patient management, especially in guiding surgical intervention and assessing the effectiveness of surgical revascularization. This paper introduces a new noninvasive magnetic resonance (MR) imaging—based method to map CVR. Preoperative and postoperative results are reported in three cases to demonstrate the efficacy of this technique in assessing vascular reserve at the microvascular level.

Methods. Three patients with angiographically confirmed moyamoya disease were evaluated before and after surgical revascularization. Measurements of CVR were obtained by rapidly manipulating end-tidal PCO2 between hypercapnic and hypocapnic states during MR imaging. The CVR maps were then calculated by comparing the percentage of changes in MR signal with changes in end-tidal PCO2.

Presurgical CVR maps showed distinct regions of positive and negative reactivity that correlated precisely with the vascular territories supplied by severely narrowed vessels. Postsurgical reactivity maps demonstrated improvement in the two patients with positive clinical outcome and no change in the patient in whom a failed superficial temporal artery—middle cerebral artery bypass was performed.

Conclusions. Magnetic imaging—based CVR mapping during rapid manipulation of end-tidal PCO2 is an exciting new method for determining the location and extent of abnormal vascular reactivity secondary to proximal large-vessel stenoses in moyamoya disease. Although the study group is small, there seems to be considerable potential for guiding preoperative decisions and monitoring efficacy of surgical revascularization.
Subarachnoid hemorrhage caused by posterior inferior cerebellar artery aneurysm with an anomalous course of the atlantoaxial segment of the vertebral artery
Authors: Ashley William W. , Chicoine Michael R.
Published: May 2009

✓ Various anatomical courses of the vertebral artery (VA) and posterior inferior cerebellar artery (PICA) have been described. The authors present a unique case of a subarachnoid hemorrhage resulting from an aneurysm in a patient with an anatomical variation of the extracranial portion of the VA and cervical origin of the PICA. The surgical implications of this variant are discussed, and the pertinent literature reviewed. Subarachnoid hemorrhage caused by rupture of a PICA aneurysm is reported for the first time in association with a rare variation of the course of the VA.
Noninvasive assessment of intracranial pressure waveforms by using pulsed phase lock loop technology
Authors: Ueno Toshiaki , Macias Brandon R. , Yost William T. , Hargens Alan R.
Published: May 2009

✓ Elevated intracranial pressure (ICP) is a major factor associated with incidences of morbidity and mortality in patients with neurological disorders. The use of conventional methods for ICP monitoring is currently limited to patients with severe neurological conditions because of the methods' invasive nature. The authors have developed an ultrasonic device capable of monitoring ICP waveforms noninvasively by using a pulsed phase lock loop (PPLL) technique. The PPLL device records skull movement (several meters) associated with ICP pulsations. The purpose of this study was to correlate PPLL waveforms with invasively measured ICP waveforms in patients at the University of California San Diego Medical Center (13 patients).

A linear regression analysis revealed a high correlation between PPLL waveforms and invasively measured ICP waveforms during the same time domain (r2 = 0.88). A coherence function analysis, which provides the fractional portion of the mean square value at the output that is contributed by the input at a certain frequency, showed medium to high correlations (r2 = 0.50–0.90) between PPLL waveforms and invasively measured ICP waveforms at each harmonic wave components. Furthermore, there was a significant correlation (r2 = 0.680, p < 0.01) in the harmonic distortion ratio (an index representing how much a given waveform is distorted from a pure sine wave) between PPLL waveforms and invasively measured ICP waveforms. In conclusion, PPLL technology enables the noninvasive evaluation of ICP dynamics in clinical settings.
George W. Crile, Ohio's first neurosurgeon, and his relationship with Harvey Cushing
Authors: Nathoo Narendra , Lautzenheiser Frederick K. , Barnett Gene H.
Published: May 2009

✓ Much has been written about Harvey Cushing, his contributions to neurosurgery, and his relationship with many of his contemporaries. Nevertheless, there is no independent report documenting his relationship with Ohio's first neurosurgeon, George W. Crile. Crile's role as a neurosurgeon is limited to the late nineteenth and early twentieth centuries, and he is best remembered for other accomplishments. Father of physiological surgery, pioneering surgeon, innovator, inventor, soldier, and the principal founder of the Cleveland Clinic Foundation, Crile lived during the golden era of surgery, when the discipline was evolving from a crude and chancy art to an applied science. Crile achieved distinction by performing and describing the first successful radical neck dissection for head and neck cancers and the first successful direct human-to-human blood transfusion. He helped introduce the measurement of blood pressure during surgery, first used cocaine for regional anesthesia in the US, proposed “anoci-anesthesia” to prevent shock during surgery, helped establish one of the first nurse anesthetist schools, and invented the Crile forceps and the pneumatic suit, which was the forerunner to the aviator's antigravity suit. He was a founding member of the American College of Surgeons, its second president (1916–1917), and chairman of the Board of Regents (1913–1939). Crile was a teacher, lecturer, and author who published more than 400 papers and 24 books.

In this report the authors trace the relationship between Crile and Cushing from their initial competition for a staff surgeon's position to their common interest in blood pressure, and their roles in the American Ambulance in France and later in World War I.
Fast forwarding: the evolution of neurosurgery
Authors: Ratcheson Robert A.
Published: May 2009

✓ Despite the major social and economic reorganization of medical practice that has taken place during the past 40 years, neurosurgery—the most fascinating specialty in all of clinical medicine—has grown and prospered. Today, this specialty is poised for an era of spectacular advancement and improvement in care; however, significant problems with the potential to retard this growth face neurosurgery. Among these problems is the medical liability situation, which has the potential to destabilize neurosurgical practices and the current health care delivery system. Other issues facing neurosurgery include the potential for loss of the unique nature of the specialty through a conversion to shift-worker surgeons and increasing reliance on profit-seeking institutions for financial stability and liability protection. Lifestyle choices are of growing importance and currently discourage women from entering the field. With a growing knowledge base, there is the recognition that it may not be possible for most individuals to master all aspects of the specialty. There is continued confusion about manpower needs. In addition, some neurosurgeons are choosing to practice in ways that fail to meet the neurosurgeon's obligations to society. There is a growing number of neurosurgeons who dislike providing trauma coverage and there is the potential for some neurosurgeons to give up intracranial neurosurgery. The author believes that it is not competition that will improve the delivery of neurosurgical care and allow for continued growth, but cooperation, and that it will be possible to alleviate many of our problems through increased regionalization of neurosurgical care delivery. This proposal has the potential to promote the formation of neurosurgical teams, ameliorate the problem of physician fatigue, allow greater development of subspecialty skills, and ease the burden of trauma call. It should allow satisfactory solutions to lifestyle considerations and encourage more women to enter the field of neurosurgery. Such a transformation would encourage advances in care to be brought rapidly into the clinical setting and allow neurosurgery to be practiced at the very highest level.
Prediction of coronary artery disease in patients undergoing carotid endarterectomy
Authors: Shimada Toshifumi , Toyoda Kazunori , Inoue Tooru , Kamouchi Masahiro , Matsumoto Takahiro , Hiyamuta Koji , Imaizumi Tsutomu , Okada Yasushi
Published: May 2009

Object. The authors determined the factors that predict the coexistence of coronary artery disease (CAD) in patients who undergo carotid endarterectomy (CEA).

Methods. Data from 200 consecutive Japanese patients who underwent CEA for extracranial carotid artery stenosis were studied. Among 73 patients with CAD, 35 (48%) had three-vessel or left main CAD (that is, severe CAD). Peripheral artery disease was an independent predictor of CAD (odds ratio [OR] 2.61, 95% confidence interval [CI] 1.08–6.3). In addition, diabetes mellitus ([DM]; OR 2.8, 95% CI 1.24–6.32) and peripheral artery disease (PAD) (OR 2.83, 95% CI 1.05–7.57) were independent predictors of severe CAD in the 200 patients. The percentage of patients with CAD as well as those with the severe form of the disease increased stepwise as the number of major coronary risk factors in patients increased. Asymptomatic CAD was newly detected during the pre-CEA assessment in 18 (25%) of the 73 patients in whom CAD was eventually diagnosed. Diabetes mellitus was an independent predictor of occult CAD among the 200 patients (OR 4.83, 95% CI 1.53–15.2).

Conclusions. In patients with DM, PAD, or multiple major coronary risk factors who have been scheduled for CEA, one should carefully search for concomitant CAD, especially severe CAD, even when the patient has had no previous episode of angina.